Loading...
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) Maxime Coquelin 2015
4 * Copyright (C) STMicroelectronics SA 2017
5 * Authors: Maxime Coquelin <mcoquelin.stm32@gmail.com>
6 * Gerald Baeza <gerald.baeza@st.com>
7 *
8 * Inspired by st-asc.c from STMicroelectronics (c)
9 */
10
11#if defined(CONFIG_SERIAL_STM32_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
12#define SUPPORT_SYSRQ
13#endif
14
15#include <linux/clk.h>
16#include <linux/console.h>
17#include <linux/delay.h>
18#include <linux/dma-direction.h>
19#include <linux/dmaengine.h>
20#include <linux/dma-mapping.h>
21#include <linux/io.h>
22#include <linux/iopoll.h>
23#include <linux/irq.h>
24#include <linux/module.h>
25#include <linux/of.h>
26#include <linux/of_platform.h>
27#include <linux/pinctrl/consumer.h>
28#include <linux/platform_device.h>
29#include <linux/pm_runtime.h>
30#include <linux/pm_wakeirq.h>
31#include <linux/serial_core.h>
32#include <linux/serial.h>
33#include <linux/spinlock.h>
34#include <linux/sysrq.h>
35#include <linux/tty_flip.h>
36#include <linux/tty.h>
37
38#include "stm32-usart.h"
39
40static void stm32_stop_tx(struct uart_port *port);
41static void stm32_transmit_chars(struct uart_port *port);
42
43static inline struct stm32_port *to_stm32_port(struct uart_port *port)
44{
45 return container_of(port, struct stm32_port, port);
46}
47
48static void stm32_set_bits(struct uart_port *port, u32 reg, u32 bits)
49{
50 u32 val;
51
52 val = readl_relaxed(port->membase + reg);
53 val |= bits;
54 writel_relaxed(val, port->membase + reg);
55}
56
57static void stm32_clr_bits(struct uart_port *port, u32 reg, u32 bits)
58{
59 u32 val;
60
61 val = readl_relaxed(port->membase + reg);
62 val &= ~bits;
63 writel_relaxed(val, port->membase + reg);
64}
65
66static void stm32_config_reg_rs485(u32 *cr1, u32 *cr3, u32 delay_ADE,
67 u32 delay_DDE, u32 baud)
68{
69 u32 rs485_deat_dedt;
70 u32 rs485_deat_dedt_max = (USART_CR1_DEAT_MASK >> USART_CR1_DEAT_SHIFT);
71 bool over8;
72
73 *cr3 |= USART_CR3_DEM;
74 over8 = *cr1 & USART_CR1_OVER8;
75
76 if (over8)
77 rs485_deat_dedt = delay_ADE * baud * 8;
78 else
79 rs485_deat_dedt = delay_ADE * baud * 16;
80
81 rs485_deat_dedt = DIV_ROUND_CLOSEST(rs485_deat_dedt, 1000);
82 rs485_deat_dedt = rs485_deat_dedt > rs485_deat_dedt_max ?
83 rs485_deat_dedt_max : rs485_deat_dedt;
84 rs485_deat_dedt = (rs485_deat_dedt << USART_CR1_DEAT_SHIFT) &
85 USART_CR1_DEAT_MASK;
86 *cr1 |= rs485_deat_dedt;
87
88 if (over8)
89 rs485_deat_dedt = delay_DDE * baud * 8;
90 else
91 rs485_deat_dedt = delay_DDE * baud * 16;
92
93 rs485_deat_dedt = DIV_ROUND_CLOSEST(rs485_deat_dedt, 1000);
94 rs485_deat_dedt = rs485_deat_dedt > rs485_deat_dedt_max ?
95 rs485_deat_dedt_max : rs485_deat_dedt;
96 rs485_deat_dedt = (rs485_deat_dedt << USART_CR1_DEDT_SHIFT) &
97 USART_CR1_DEDT_MASK;
98 *cr1 |= rs485_deat_dedt;
99}
100
101static int stm32_config_rs485(struct uart_port *port,
102 struct serial_rs485 *rs485conf)
103{
104 struct stm32_port *stm32_port = to_stm32_port(port);
105 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
106 struct stm32_usart_config *cfg = &stm32_port->info->cfg;
107 u32 usartdiv, baud, cr1, cr3;
108 bool over8;
109
110 stm32_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
111
112 port->rs485 = *rs485conf;
113
114 rs485conf->flags |= SER_RS485_RX_DURING_TX;
115
116 if (rs485conf->flags & SER_RS485_ENABLED) {
117 cr1 = readl_relaxed(port->membase + ofs->cr1);
118 cr3 = readl_relaxed(port->membase + ofs->cr3);
119 usartdiv = readl_relaxed(port->membase + ofs->brr);
120 usartdiv = usartdiv & GENMASK(15, 0);
121 over8 = cr1 & USART_CR1_OVER8;
122
123 if (over8)
124 usartdiv = usartdiv | (usartdiv & GENMASK(4, 0))
125 << USART_BRR_04_R_SHIFT;
126
127 baud = DIV_ROUND_CLOSEST(port->uartclk, usartdiv);
128 stm32_config_reg_rs485(&cr1, &cr3,
129 rs485conf->delay_rts_before_send,
130 rs485conf->delay_rts_after_send, baud);
131
132 if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
133 cr3 &= ~USART_CR3_DEP;
134 rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
135 } else {
136 cr3 |= USART_CR3_DEP;
137 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
138 }
139
140 writel_relaxed(cr3, port->membase + ofs->cr3);
141 writel_relaxed(cr1, port->membase + ofs->cr1);
142 } else {
143 stm32_clr_bits(port, ofs->cr3, USART_CR3_DEM | USART_CR3_DEP);
144 stm32_clr_bits(port, ofs->cr1,
145 USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
146 }
147
148 stm32_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
149
150 return 0;
151}
152
153static int stm32_init_rs485(struct uart_port *port,
154 struct platform_device *pdev)
155{
156 struct serial_rs485 *rs485conf = &port->rs485;
157
158 rs485conf->flags = 0;
159 rs485conf->delay_rts_before_send = 0;
160 rs485conf->delay_rts_after_send = 0;
161
162 if (!pdev->dev.of_node)
163 return -ENODEV;
164
165 uart_get_rs485_mode(&pdev->dev, rs485conf);
166
167 return 0;
168}
169
170static int stm32_pending_rx(struct uart_port *port, u32 *sr, int *last_res,
171 bool threaded)
172{
173 struct stm32_port *stm32_port = to_stm32_port(port);
174 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
175 enum dma_status status;
176 struct dma_tx_state state;
177
178 *sr = readl_relaxed(port->membase + ofs->isr);
179
180 if (threaded && stm32_port->rx_ch) {
181 status = dmaengine_tx_status(stm32_port->rx_ch,
182 stm32_port->rx_ch->cookie,
183 &state);
184 if ((status == DMA_IN_PROGRESS) &&
185 (*last_res != state.residue))
186 return 1;
187 else
188 return 0;
189 } else if (*sr & USART_SR_RXNE) {
190 return 1;
191 }
192 return 0;
193}
194
195static unsigned long stm32_get_char(struct uart_port *port, u32 *sr,
196 int *last_res)
197{
198 struct stm32_port *stm32_port = to_stm32_port(port);
199 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
200 unsigned long c;
201
202 if (stm32_port->rx_ch) {
203 c = stm32_port->rx_buf[RX_BUF_L - (*last_res)--];
204 if ((*last_res) == 0)
205 *last_res = RX_BUF_L;
206 } else {
207 c = readl_relaxed(port->membase + ofs->rdr);
208 /* apply RDR data mask */
209 c &= stm32_port->rdr_mask;
210 }
211
212 return c;
213}
214
215static void stm32_receive_chars(struct uart_port *port, bool threaded)
216{
217 struct tty_port *tport = &port->state->port;
218 struct stm32_port *stm32_port = to_stm32_port(port);
219 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
220 unsigned long c;
221 u32 sr;
222 char flag;
223
224 if (irqd_is_wakeup_set(irq_get_irq_data(port->irq)))
225 pm_wakeup_event(tport->tty->dev, 0);
226
227 while (stm32_pending_rx(port, &sr, &stm32_port->last_res, threaded)) {
228 sr |= USART_SR_DUMMY_RX;
229 flag = TTY_NORMAL;
230
231 /*
232 * Status bits has to be cleared before reading the RDR:
233 * In FIFO mode, reading the RDR will pop the next data
234 * (if any) along with its status bits into the SR.
235 * Not doing so leads to misalignement between RDR and SR,
236 * and clear status bits of the next rx data.
237 *
238 * Clear errors flags for stm32f7 and stm32h7 compatible
239 * devices. On stm32f4 compatible devices, the error bit is
240 * cleared by the sequence [read SR - read DR].
241 */
242 if ((sr & USART_SR_ERR_MASK) && ofs->icr != UNDEF_REG)
243 stm32_clr_bits(port, ofs->icr, USART_ICR_ORECF |
244 USART_ICR_PECF | USART_ICR_FECF);
245
246 c = stm32_get_char(port, &sr, &stm32_port->last_res);
247 port->icount.rx++;
248 if (sr & USART_SR_ERR_MASK) {
249 if (sr & USART_SR_ORE) {
250 port->icount.overrun++;
251 } else if (sr & USART_SR_PE) {
252 port->icount.parity++;
253 } else if (sr & USART_SR_FE) {
254 /* Break detection if character is null */
255 if (!c) {
256 port->icount.brk++;
257 if (uart_handle_break(port))
258 continue;
259 } else {
260 port->icount.frame++;
261 }
262 }
263
264 sr &= port->read_status_mask;
265
266 if (sr & USART_SR_PE) {
267 flag = TTY_PARITY;
268 } else if (sr & USART_SR_FE) {
269 if (!c)
270 flag = TTY_BREAK;
271 else
272 flag = TTY_FRAME;
273 }
274 }
275
276 if (uart_handle_sysrq_char(port, c))
277 continue;
278 uart_insert_char(port, sr, USART_SR_ORE, c, flag);
279 }
280
281 spin_unlock(&port->lock);
282 tty_flip_buffer_push(tport);
283 spin_lock(&port->lock);
284}
285
286static void stm32_tx_dma_complete(void *arg)
287{
288 struct uart_port *port = arg;
289 struct stm32_port *stm32port = to_stm32_port(port);
290 struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
291
292 stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
293 stm32port->tx_dma_busy = false;
294
295 /* Let's see if we have pending data to send */
296 stm32_transmit_chars(port);
297}
298
299static void stm32_tx_interrupt_enable(struct uart_port *port)
300{
301 struct stm32_port *stm32_port = to_stm32_port(port);
302 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
303
304 /*
305 * Enables TX FIFO threashold irq when FIFO is enabled,
306 * or TX empty irq when FIFO is disabled
307 */
308 if (stm32_port->fifoen)
309 stm32_set_bits(port, ofs->cr3, USART_CR3_TXFTIE);
310 else
311 stm32_set_bits(port, ofs->cr1, USART_CR1_TXEIE);
312}
313
314static void stm32_tx_interrupt_disable(struct uart_port *port)
315{
316 struct stm32_port *stm32_port = to_stm32_port(port);
317 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
318
319 if (stm32_port->fifoen)
320 stm32_clr_bits(port, ofs->cr3, USART_CR3_TXFTIE);
321 else
322 stm32_clr_bits(port, ofs->cr1, USART_CR1_TXEIE);
323}
324
325static void stm32_transmit_chars_pio(struct uart_port *port)
326{
327 struct stm32_port *stm32_port = to_stm32_port(port);
328 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
329 struct circ_buf *xmit = &port->state->xmit;
330
331 if (stm32_port->tx_dma_busy) {
332 stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
333 stm32_port->tx_dma_busy = false;
334 }
335
336 while (!uart_circ_empty(xmit)) {
337 /* Check that TDR is empty before filling FIFO */
338 if (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE))
339 break;
340 writel_relaxed(xmit->buf[xmit->tail], port->membase + ofs->tdr);
341 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
342 port->icount.tx++;
343 }
344
345 /* rely on TXE irq (mask or unmask) for sending remaining data */
346 if (uart_circ_empty(xmit))
347 stm32_tx_interrupt_disable(port);
348 else
349 stm32_tx_interrupt_enable(port);
350}
351
352static void stm32_transmit_chars_dma(struct uart_port *port)
353{
354 struct stm32_port *stm32port = to_stm32_port(port);
355 struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
356 struct circ_buf *xmit = &port->state->xmit;
357 struct dma_async_tx_descriptor *desc = NULL;
358 dma_cookie_t cookie;
359 unsigned int count, i;
360
361 if (stm32port->tx_dma_busy)
362 return;
363
364 stm32port->tx_dma_busy = true;
365
366 count = uart_circ_chars_pending(xmit);
367
368 if (count > TX_BUF_L)
369 count = TX_BUF_L;
370
371 if (xmit->tail < xmit->head) {
372 memcpy(&stm32port->tx_buf[0], &xmit->buf[xmit->tail], count);
373 } else {
374 size_t one = UART_XMIT_SIZE - xmit->tail;
375 size_t two;
376
377 if (one > count)
378 one = count;
379 two = count - one;
380
381 memcpy(&stm32port->tx_buf[0], &xmit->buf[xmit->tail], one);
382 if (two)
383 memcpy(&stm32port->tx_buf[one], &xmit->buf[0], two);
384 }
385
386 desc = dmaengine_prep_slave_single(stm32port->tx_ch,
387 stm32port->tx_dma_buf,
388 count,
389 DMA_MEM_TO_DEV,
390 DMA_PREP_INTERRUPT);
391
392 if (!desc) {
393 for (i = count; i > 0; i--)
394 stm32_transmit_chars_pio(port);
395 return;
396 }
397
398 desc->callback = stm32_tx_dma_complete;
399 desc->callback_param = port;
400
401 /* Push current DMA TX transaction in the pending queue */
402 cookie = dmaengine_submit(desc);
403
404 /* Issue pending DMA TX requests */
405 dma_async_issue_pending(stm32port->tx_ch);
406
407 stm32_set_bits(port, ofs->cr3, USART_CR3_DMAT);
408
409 xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
410 port->icount.tx += count;
411}
412
413static void stm32_transmit_chars(struct uart_port *port)
414{
415 struct stm32_port *stm32_port = to_stm32_port(port);
416 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
417 struct circ_buf *xmit = &port->state->xmit;
418
419 if (port->x_char) {
420 if (stm32_port->tx_dma_busy)
421 stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
422 writel_relaxed(port->x_char, port->membase + ofs->tdr);
423 port->x_char = 0;
424 port->icount.tx++;
425 if (stm32_port->tx_dma_busy)
426 stm32_set_bits(port, ofs->cr3, USART_CR3_DMAT);
427 return;
428 }
429
430 if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
431 stm32_tx_interrupt_disable(port);
432 return;
433 }
434
435 if (ofs->icr == UNDEF_REG)
436 stm32_clr_bits(port, ofs->isr, USART_SR_TC);
437 else
438 stm32_set_bits(port, ofs->icr, USART_ICR_TCCF);
439
440 if (stm32_port->tx_ch)
441 stm32_transmit_chars_dma(port);
442 else
443 stm32_transmit_chars_pio(port);
444
445 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
446 uart_write_wakeup(port);
447
448 if (uart_circ_empty(xmit))
449 stm32_tx_interrupt_disable(port);
450}
451
452static irqreturn_t stm32_interrupt(int irq, void *ptr)
453{
454 struct uart_port *port = ptr;
455 struct stm32_port *stm32_port = to_stm32_port(port);
456 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
457 u32 sr;
458
459 spin_lock(&port->lock);
460
461 sr = readl_relaxed(port->membase + ofs->isr);
462
463 if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG)
464 writel_relaxed(USART_ICR_RTOCF,
465 port->membase + ofs->icr);
466
467 if ((sr & USART_SR_WUF) && (ofs->icr != UNDEF_REG))
468 writel_relaxed(USART_ICR_WUCF,
469 port->membase + ofs->icr);
470
471 if ((sr & USART_SR_RXNE) && !(stm32_port->rx_ch))
472 stm32_receive_chars(port, false);
473
474 if ((sr & USART_SR_TXE) && !(stm32_port->tx_ch))
475 stm32_transmit_chars(port);
476
477 spin_unlock(&port->lock);
478
479 if (stm32_port->rx_ch)
480 return IRQ_WAKE_THREAD;
481 else
482 return IRQ_HANDLED;
483}
484
485static irqreturn_t stm32_threaded_interrupt(int irq, void *ptr)
486{
487 struct uart_port *port = ptr;
488 struct stm32_port *stm32_port = to_stm32_port(port);
489
490 spin_lock(&port->lock);
491
492 if (stm32_port->rx_ch)
493 stm32_receive_chars(port, true);
494
495 spin_unlock(&port->lock);
496
497 return IRQ_HANDLED;
498}
499
500static unsigned int stm32_tx_empty(struct uart_port *port)
501{
502 struct stm32_port *stm32_port = to_stm32_port(port);
503 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
504
505 return readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE;
506}
507
508static void stm32_set_mctrl(struct uart_port *port, unsigned int mctrl)
509{
510 struct stm32_port *stm32_port = to_stm32_port(port);
511 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
512
513 if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS))
514 stm32_set_bits(port, ofs->cr3, USART_CR3_RTSE);
515 else
516 stm32_clr_bits(port, ofs->cr3, USART_CR3_RTSE);
517}
518
519static unsigned int stm32_get_mctrl(struct uart_port *port)
520{
521 /* This routine is used to get signals of: DCD, DSR, RI, and CTS */
522 return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
523}
524
525/* Transmit stop */
526static void stm32_stop_tx(struct uart_port *port)
527{
528 stm32_tx_interrupt_disable(port);
529}
530
531/* There are probably characters waiting to be transmitted. */
532static void stm32_start_tx(struct uart_port *port)
533{
534 struct circ_buf *xmit = &port->state->xmit;
535
536 if (uart_circ_empty(xmit))
537 return;
538
539 stm32_transmit_chars(port);
540}
541
542/* Throttle the remote when input buffer is about to overflow. */
543static void stm32_throttle(struct uart_port *port)
544{
545 struct stm32_port *stm32_port = to_stm32_port(port);
546 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
547 unsigned long flags;
548
549 spin_lock_irqsave(&port->lock, flags);
550 stm32_clr_bits(port, ofs->cr1, stm32_port->cr1_irq);
551 if (stm32_port->cr3_irq)
552 stm32_clr_bits(port, ofs->cr3, stm32_port->cr3_irq);
553
554 spin_unlock_irqrestore(&port->lock, flags);
555}
556
557/* Unthrottle the remote, the input buffer can now accept data. */
558static void stm32_unthrottle(struct uart_port *port)
559{
560 struct stm32_port *stm32_port = to_stm32_port(port);
561 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
562 unsigned long flags;
563
564 spin_lock_irqsave(&port->lock, flags);
565 stm32_set_bits(port, ofs->cr1, stm32_port->cr1_irq);
566 if (stm32_port->cr3_irq)
567 stm32_set_bits(port, ofs->cr3, stm32_port->cr3_irq);
568
569 spin_unlock_irqrestore(&port->lock, flags);
570}
571
572/* Receive stop */
573static void stm32_stop_rx(struct uart_port *port)
574{
575 struct stm32_port *stm32_port = to_stm32_port(port);
576 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
577
578 stm32_clr_bits(port, ofs->cr1, stm32_port->cr1_irq);
579 if (stm32_port->cr3_irq)
580 stm32_clr_bits(port, ofs->cr3, stm32_port->cr3_irq);
581
582}
583
584/* Handle breaks - ignored by us */
585static void stm32_break_ctl(struct uart_port *port, int break_state)
586{
587}
588
589static int stm32_startup(struct uart_port *port)
590{
591 struct stm32_port *stm32_port = to_stm32_port(port);
592 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
593 const char *name = to_platform_device(port->dev)->name;
594 u32 val;
595 int ret;
596
597 ret = request_threaded_irq(port->irq, stm32_interrupt,
598 stm32_threaded_interrupt,
599 IRQF_NO_SUSPEND, name, port);
600 if (ret)
601 return ret;
602
603 /* RX FIFO Flush */
604 if (ofs->rqr != UNDEF_REG)
605 stm32_set_bits(port, ofs->rqr, USART_RQR_RXFRQ);
606
607 /* Tx and RX FIFO configuration */
608 if (stm32_port->fifoen) {
609 val = readl_relaxed(port->membase + ofs->cr3);
610 val &= ~(USART_CR3_TXFTCFG_MASK | USART_CR3_RXFTCFG_MASK);
611 val |= USART_CR3_TXFTCFG_HALF << USART_CR3_TXFTCFG_SHIFT;
612 val |= USART_CR3_RXFTCFG_HALF << USART_CR3_RXFTCFG_SHIFT;
613 writel_relaxed(val, port->membase + ofs->cr3);
614 }
615
616 /* RX FIFO enabling */
617 val = stm32_port->cr1_irq | USART_CR1_RE;
618 if (stm32_port->fifoen)
619 val |= USART_CR1_FIFOEN;
620 stm32_set_bits(port, ofs->cr1, val);
621
622 return 0;
623}
624
625static void stm32_shutdown(struct uart_port *port)
626{
627 struct stm32_port *stm32_port = to_stm32_port(port);
628 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
629 struct stm32_usart_config *cfg = &stm32_port->info->cfg;
630 u32 val, isr;
631 int ret;
632
633 val = USART_CR1_TXEIE | USART_CR1_TE;
634 val |= stm32_port->cr1_irq | USART_CR1_RE;
635 val |= BIT(cfg->uart_enable_bit);
636 if (stm32_port->fifoen)
637 val |= USART_CR1_FIFOEN;
638
639 ret = readl_relaxed_poll_timeout(port->membase + ofs->isr,
640 isr, (isr & USART_SR_TC),
641 10, 100000);
642
643 if (ret)
644 dev_err(port->dev, "transmission complete not set\n");
645
646 stm32_clr_bits(port, ofs->cr1, val);
647
648 free_irq(port->irq, port);
649}
650
651static unsigned int stm32_get_databits(struct ktermios *termios)
652{
653 unsigned int bits;
654
655 tcflag_t cflag = termios->c_cflag;
656
657 switch (cflag & CSIZE) {
658 /*
659 * CSIZE settings are not necessarily supported in hardware.
660 * CSIZE unsupported configurations are handled here to set word length
661 * to 8 bits word as default configuration and to print debug message.
662 */
663 case CS5:
664 bits = 5;
665 break;
666 case CS6:
667 bits = 6;
668 break;
669 case CS7:
670 bits = 7;
671 break;
672 /* default including CS8 */
673 default:
674 bits = 8;
675 break;
676 }
677
678 return bits;
679}
680
681static void stm32_set_termios(struct uart_port *port, struct ktermios *termios,
682 struct ktermios *old)
683{
684 struct stm32_port *stm32_port = to_stm32_port(port);
685 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
686 struct stm32_usart_config *cfg = &stm32_port->info->cfg;
687 struct serial_rs485 *rs485conf = &port->rs485;
688 unsigned int baud, bits;
689 u32 usartdiv, mantissa, fraction, oversampling;
690 tcflag_t cflag = termios->c_cflag;
691 u32 cr1, cr2, cr3;
692 unsigned long flags;
693
694 if (!stm32_port->hw_flow_control)
695 cflag &= ~CRTSCTS;
696
697 baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 8);
698
699 spin_lock_irqsave(&port->lock, flags);
700
701 /* Stop serial port and reset value */
702 writel_relaxed(0, port->membase + ofs->cr1);
703
704 /* flush RX & TX FIFO */
705 if (ofs->rqr != UNDEF_REG)
706 stm32_set_bits(port, ofs->rqr,
707 USART_RQR_TXFRQ | USART_RQR_RXFRQ);
708
709 cr1 = USART_CR1_TE | USART_CR1_RE;
710 if (stm32_port->fifoen)
711 cr1 |= USART_CR1_FIFOEN;
712 cr2 = 0;
713 cr3 = readl_relaxed(port->membase + ofs->cr3);
714 cr3 &= USART_CR3_TXFTIE | USART_CR3_RXFTCFG_MASK | USART_CR3_RXFTIE
715 | USART_CR3_TXFTCFG_MASK;
716
717 if (cflag & CSTOPB)
718 cr2 |= USART_CR2_STOP_2B;
719
720 bits = stm32_get_databits(termios);
721 stm32_port->rdr_mask = (BIT(bits) - 1);
722
723 if (cflag & PARENB) {
724 bits++;
725 cr1 |= USART_CR1_PCE;
726 }
727
728 /*
729 * Word length configuration:
730 * CS8 + parity, 9 bits word aka [M1:M0] = 0b01
731 * CS7 or (CS6 + parity), 7 bits word aka [M1:M0] = 0b10
732 * CS8 or (CS7 + parity), 8 bits word aka [M1:M0] = 0b00
733 * M0 and M1 already cleared by cr1 initialization.
734 */
735 if (bits == 9)
736 cr1 |= USART_CR1_M0;
737 else if ((bits == 7) && cfg->has_7bits_data)
738 cr1 |= USART_CR1_M1;
739 else if (bits != 8)
740 dev_dbg(port->dev, "Unsupported data bits config: %u bits\n"
741 , bits);
742
743 if (ofs->rtor != UNDEF_REG && (stm32_port->rx_ch ||
744 stm32_port->fifoen)) {
745 if (cflag & CSTOPB)
746 bits = bits + 3; /* 1 start bit + 2 stop bits */
747 else
748 bits = bits + 2; /* 1 start bit + 1 stop bit */
749
750 /* RX timeout irq to occur after last stop bit + bits */
751 stm32_port->cr1_irq = USART_CR1_RTOIE;
752 writel_relaxed(bits, port->membase + ofs->rtor);
753 cr2 |= USART_CR2_RTOEN;
754 /* Not using dma, enable fifo threshold irq */
755 if (!stm32_port->rx_ch)
756 stm32_port->cr3_irq = USART_CR3_RXFTIE;
757 }
758
759 cr1 |= stm32_port->cr1_irq;
760 cr3 |= stm32_port->cr3_irq;
761
762 if (cflag & PARODD)
763 cr1 |= USART_CR1_PS;
764
765 port->status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS);
766 if (cflag & CRTSCTS) {
767 port->status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
768 cr3 |= USART_CR3_CTSE | USART_CR3_RTSE;
769 }
770
771 usartdiv = DIV_ROUND_CLOSEST(port->uartclk, baud);
772
773 /*
774 * The USART supports 16 or 8 times oversampling.
775 * By default we prefer 16 times oversampling, so that the receiver
776 * has a better tolerance to clock deviations.
777 * 8 times oversampling is only used to achieve higher speeds.
778 */
779 if (usartdiv < 16) {
780 oversampling = 8;
781 cr1 |= USART_CR1_OVER8;
782 stm32_set_bits(port, ofs->cr1, USART_CR1_OVER8);
783 } else {
784 oversampling = 16;
785 cr1 &= ~USART_CR1_OVER8;
786 stm32_clr_bits(port, ofs->cr1, USART_CR1_OVER8);
787 }
788
789 mantissa = (usartdiv / oversampling) << USART_BRR_DIV_M_SHIFT;
790 fraction = usartdiv % oversampling;
791 writel_relaxed(mantissa | fraction, port->membase + ofs->brr);
792
793 uart_update_timeout(port, cflag, baud);
794
795 port->read_status_mask = USART_SR_ORE;
796 if (termios->c_iflag & INPCK)
797 port->read_status_mask |= USART_SR_PE | USART_SR_FE;
798 if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
799 port->read_status_mask |= USART_SR_FE;
800
801 /* Characters to ignore */
802 port->ignore_status_mask = 0;
803 if (termios->c_iflag & IGNPAR)
804 port->ignore_status_mask = USART_SR_PE | USART_SR_FE;
805 if (termios->c_iflag & IGNBRK) {
806 port->ignore_status_mask |= USART_SR_FE;
807 /*
808 * If we're ignoring parity and break indicators,
809 * ignore overruns too (for real raw support).
810 */
811 if (termios->c_iflag & IGNPAR)
812 port->ignore_status_mask |= USART_SR_ORE;
813 }
814
815 /* Ignore all characters if CREAD is not set */
816 if ((termios->c_cflag & CREAD) == 0)
817 port->ignore_status_mask |= USART_SR_DUMMY_RX;
818
819 if (stm32_port->rx_ch)
820 cr3 |= USART_CR3_DMAR;
821
822 if (rs485conf->flags & SER_RS485_ENABLED) {
823 stm32_config_reg_rs485(&cr1, &cr3,
824 rs485conf->delay_rts_before_send,
825 rs485conf->delay_rts_after_send, baud);
826 if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
827 cr3 &= ~USART_CR3_DEP;
828 rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
829 } else {
830 cr3 |= USART_CR3_DEP;
831 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
832 }
833
834 } else {
835 cr3 &= ~(USART_CR3_DEM | USART_CR3_DEP);
836 cr1 &= ~(USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
837 }
838
839 writel_relaxed(cr3, port->membase + ofs->cr3);
840 writel_relaxed(cr2, port->membase + ofs->cr2);
841 writel_relaxed(cr1, port->membase + ofs->cr1);
842
843 stm32_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
844 spin_unlock_irqrestore(&port->lock, flags);
845}
846
847static const char *stm32_type(struct uart_port *port)
848{
849 return (port->type == PORT_STM32) ? DRIVER_NAME : NULL;
850}
851
852static void stm32_release_port(struct uart_port *port)
853{
854}
855
856static int stm32_request_port(struct uart_port *port)
857{
858 return 0;
859}
860
861static void stm32_config_port(struct uart_port *port, int flags)
862{
863 if (flags & UART_CONFIG_TYPE)
864 port->type = PORT_STM32;
865}
866
867static int
868stm32_verify_port(struct uart_port *port, struct serial_struct *ser)
869{
870 /* No user changeable parameters */
871 return -EINVAL;
872}
873
874static void stm32_pm(struct uart_port *port, unsigned int state,
875 unsigned int oldstate)
876{
877 struct stm32_port *stm32port = container_of(port,
878 struct stm32_port, port);
879 struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
880 struct stm32_usart_config *cfg = &stm32port->info->cfg;
881 unsigned long flags = 0;
882
883 switch (state) {
884 case UART_PM_STATE_ON:
885 pm_runtime_get_sync(port->dev);
886 break;
887 case UART_PM_STATE_OFF:
888 spin_lock_irqsave(&port->lock, flags);
889 stm32_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
890 spin_unlock_irqrestore(&port->lock, flags);
891 pm_runtime_put_sync(port->dev);
892 break;
893 }
894}
895
896static const struct uart_ops stm32_uart_ops = {
897 .tx_empty = stm32_tx_empty,
898 .set_mctrl = stm32_set_mctrl,
899 .get_mctrl = stm32_get_mctrl,
900 .stop_tx = stm32_stop_tx,
901 .start_tx = stm32_start_tx,
902 .throttle = stm32_throttle,
903 .unthrottle = stm32_unthrottle,
904 .stop_rx = stm32_stop_rx,
905 .break_ctl = stm32_break_ctl,
906 .startup = stm32_startup,
907 .shutdown = stm32_shutdown,
908 .set_termios = stm32_set_termios,
909 .pm = stm32_pm,
910 .type = stm32_type,
911 .release_port = stm32_release_port,
912 .request_port = stm32_request_port,
913 .config_port = stm32_config_port,
914 .verify_port = stm32_verify_port,
915};
916
917static int stm32_init_port(struct stm32_port *stm32port,
918 struct platform_device *pdev)
919{
920 struct uart_port *port = &stm32port->port;
921 struct resource *res;
922 int ret;
923
924 port->iotype = UPIO_MEM;
925 port->flags = UPF_BOOT_AUTOCONF;
926 port->ops = &stm32_uart_ops;
927 port->dev = &pdev->dev;
928 port->fifosize = stm32port->info->cfg.fifosize;
929
930 ret = platform_get_irq(pdev, 0);
931 if (ret <= 0)
932 return ret ? : -ENODEV;
933 port->irq = ret;
934
935 port->rs485_config = stm32_config_rs485;
936
937 stm32_init_rs485(port, pdev);
938
939 if (stm32port->info->cfg.has_wakeup) {
940 stm32port->wakeirq = platform_get_irq(pdev, 1);
941 if (stm32port->wakeirq <= 0 && stm32port->wakeirq != -ENXIO)
942 return stm32port->wakeirq ? : -ENODEV;
943 }
944
945 stm32port->fifoen = stm32port->info->cfg.has_fifo;
946
947 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
948 port->membase = devm_ioremap_resource(&pdev->dev, res);
949 if (IS_ERR(port->membase))
950 return PTR_ERR(port->membase);
951 port->mapbase = res->start;
952
953 spin_lock_init(&port->lock);
954
955 stm32port->clk = devm_clk_get(&pdev->dev, NULL);
956 if (IS_ERR(stm32port->clk))
957 return PTR_ERR(stm32port->clk);
958
959 /* Ensure that clk rate is correct by enabling the clk */
960 ret = clk_prepare_enable(stm32port->clk);
961 if (ret)
962 return ret;
963
964 stm32port->port.uartclk = clk_get_rate(stm32port->clk);
965 if (!stm32port->port.uartclk) {
966 clk_disable_unprepare(stm32port->clk);
967 ret = -EINVAL;
968 }
969
970 return ret;
971}
972
973static struct stm32_port *stm32_of_get_stm32_port(struct platform_device *pdev)
974{
975 struct device_node *np = pdev->dev.of_node;
976 int id;
977
978 if (!np)
979 return NULL;
980
981 id = of_alias_get_id(np, "serial");
982 if (id < 0) {
983 dev_err(&pdev->dev, "failed to get alias id, errno %d\n", id);
984 return NULL;
985 }
986
987 if (WARN_ON(id >= STM32_MAX_PORTS))
988 return NULL;
989
990 stm32_ports[id].hw_flow_control = of_property_read_bool(np,
991 "st,hw-flow-ctrl");
992 stm32_ports[id].port.line = id;
993 stm32_ports[id].cr1_irq = USART_CR1_RXNEIE;
994 stm32_ports[id].cr3_irq = 0;
995 stm32_ports[id].last_res = RX_BUF_L;
996 return &stm32_ports[id];
997}
998
999#ifdef CONFIG_OF
1000static const struct of_device_id stm32_match[] = {
1001 { .compatible = "st,stm32-uart", .data = &stm32f4_info},
1002 { .compatible = "st,stm32f7-uart", .data = &stm32f7_info},
1003 { .compatible = "st,stm32h7-uart", .data = &stm32h7_info},
1004 {},
1005};
1006
1007MODULE_DEVICE_TABLE(of, stm32_match);
1008#endif
1009
1010static int stm32_of_dma_rx_probe(struct stm32_port *stm32port,
1011 struct platform_device *pdev)
1012{
1013 struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
1014 struct uart_port *port = &stm32port->port;
1015 struct device *dev = &pdev->dev;
1016 struct dma_slave_config config;
1017 struct dma_async_tx_descriptor *desc = NULL;
1018 dma_cookie_t cookie;
1019 int ret;
1020
1021 /* Request DMA RX channel */
1022 stm32port->rx_ch = dma_request_slave_channel(dev, "rx");
1023 if (!stm32port->rx_ch) {
1024 dev_info(dev, "rx dma alloc failed\n");
1025 return -ENODEV;
1026 }
1027 stm32port->rx_buf = dma_alloc_coherent(&pdev->dev, RX_BUF_L,
1028 &stm32port->rx_dma_buf,
1029 GFP_KERNEL);
1030 if (!stm32port->rx_buf) {
1031 ret = -ENOMEM;
1032 goto alloc_err;
1033 }
1034
1035 /* Configure DMA channel */
1036 memset(&config, 0, sizeof(config));
1037 config.src_addr = port->mapbase + ofs->rdr;
1038 config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1039
1040 ret = dmaengine_slave_config(stm32port->rx_ch, &config);
1041 if (ret < 0) {
1042 dev_err(dev, "rx dma channel config failed\n");
1043 ret = -ENODEV;
1044 goto config_err;
1045 }
1046
1047 /* Prepare a DMA cyclic transaction */
1048 desc = dmaengine_prep_dma_cyclic(stm32port->rx_ch,
1049 stm32port->rx_dma_buf,
1050 RX_BUF_L, RX_BUF_P, DMA_DEV_TO_MEM,
1051 DMA_PREP_INTERRUPT);
1052 if (!desc) {
1053 dev_err(dev, "rx dma prep cyclic failed\n");
1054 ret = -ENODEV;
1055 goto config_err;
1056 }
1057
1058 /* No callback as dma buffer is drained on usart interrupt */
1059 desc->callback = NULL;
1060 desc->callback_param = NULL;
1061
1062 /* Push current DMA transaction in the pending queue */
1063 cookie = dmaengine_submit(desc);
1064
1065 /* Issue pending DMA requests */
1066 dma_async_issue_pending(stm32port->rx_ch);
1067
1068 return 0;
1069
1070config_err:
1071 dma_free_coherent(&pdev->dev,
1072 RX_BUF_L, stm32port->rx_buf,
1073 stm32port->rx_dma_buf);
1074
1075alloc_err:
1076 dma_release_channel(stm32port->rx_ch);
1077 stm32port->rx_ch = NULL;
1078
1079 return ret;
1080}
1081
1082static int stm32_of_dma_tx_probe(struct stm32_port *stm32port,
1083 struct platform_device *pdev)
1084{
1085 struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
1086 struct uart_port *port = &stm32port->port;
1087 struct device *dev = &pdev->dev;
1088 struct dma_slave_config config;
1089 int ret;
1090
1091 stm32port->tx_dma_busy = false;
1092
1093 /* Request DMA TX channel */
1094 stm32port->tx_ch = dma_request_slave_channel(dev, "tx");
1095 if (!stm32port->tx_ch) {
1096 dev_info(dev, "tx dma alloc failed\n");
1097 return -ENODEV;
1098 }
1099 stm32port->tx_buf = dma_alloc_coherent(&pdev->dev, TX_BUF_L,
1100 &stm32port->tx_dma_buf,
1101 GFP_KERNEL);
1102 if (!stm32port->tx_buf) {
1103 ret = -ENOMEM;
1104 goto alloc_err;
1105 }
1106
1107 /* Configure DMA channel */
1108 memset(&config, 0, sizeof(config));
1109 config.dst_addr = port->mapbase + ofs->tdr;
1110 config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1111
1112 ret = dmaengine_slave_config(stm32port->tx_ch, &config);
1113 if (ret < 0) {
1114 dev_err(dev, "tx dma channel config failed\n");
1115 ret = -ENODEV;
1116 goto config_err;
1117 }
1118
1119 return 0;
1120
1121config_err:
1122 dma_free_coherent(&pdev->dev,
1123 TX_BUF_L, stm32port->tx_buf,
1124 stm32port->tx_dma_buf);
1125
1126alloc_err:
1127 dma_release_channel(stm32port->tx_ch);
1128 stm32port->tx_ch = NULL;
1129
1130 return ret;
1131}
1132
1133static int stm32_serial_probe(struct platform_device *pdev)
1134{
1135 const struct of_device_id *match;
1136 struct stm32_port *stm32port;
1137 int ret;
1138
1139 stm32port = stm32_of_get_stm32_port(pdev);
1140 if (!stm32port)
1141 return -ENODEV;
1142
1143 match = of_match_device(stm32_match, &pdev->dev);
1144 if (match && match->data)
1145 stm32port->info = (struct stm32_usart_info *)match->data;
1146 else
1147 return -EINVAL;
1148
1149 ret = stm32_init_port(stm32port, pdev);
1150 if (ret)
1151 return ret;
1152
1153 if (stm32port->wakeirq > 0) {
1154 ret = device_init_wakeup(&pdev->dev, true);
1155 if (ret)
1156 goto err_uninit;
1157
1158 ret = dev_pm_set_dedicated_wake_irq(&pdev->dev,
1159 stm32port->wakeirq);
1160 if (ret)
1161 goto err_nowup;
1162
1163 device_set_wakeup_enable(&pdev->dev, false);
1164 }
1165
1166 ret = uart_add_one_port(&stm32_usart_driver, &stm32port->port);
1167 if (ret)
1168 goto err_wirq;
1169
1170 ret = stm32_of_dma_rx_probe(stm32port, pdev);
1171 if (ret)
1172 dev_info(&pdev->dev, "interrupt mode used for rx (no dma)\n");
1173
1174 ret = stm32_of_dma_tx_probe(stm32port, pdev);
1175 if (ret)
1176 dev_info(&pdev->dev, "interrupt mode used for tx (no dma)\n");
1177
1178 platform_set_drvdata(pdev, &stm32port->port);
1179
1180 pm_runtime_get_noresume(&pdev->dev);
1181 pm_runtime_set_active(&pdev->dev);
1182 pm_runtime_enable(&pdev->dev);
1183 pm_runtime_put_sync(&pdev->dev);
1184
1185 return 0;
1186
1187err_wirq:
1188 if (stm32port->wakeirq > 0)
1189 dev_pm_clear_wake_irq(&pdev->dev);
1190
1191err_nowup:
1192 if (stm32port->wakeirq > 0)
1193 device_init_wakeup(&pdev->dev, false);
1194
1195err_uninit:
1196 clk_disable_unprepare(stm32port->clk);
1197
1198 return ret;
1199}
1200
1201static int stm32_serial_remove(struct platform_device *pdev)
1202{
1203 struct uart_port *port = platform_get_drvdata(pdev);
1204 struct stm32_port *stm32_port = to_stm32_port(port);
1205 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1206 int err;
1207
1208 pm_runtime_get_sync(&pdev->dev);
1209
1210 stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAR);
1211
1212 if (stm32_port->rx_ch)
1213 dma_release_channel(stm32_port->rx_ch);
1214
1215 if (stm32_port->rx_dma_buf)
1216 dma_free_coherent(&pdev->dev,
1217 RX_BUF_L, stm32_port->rx_buf,
1218 stm32_port->rx_dma_buf);
1219
1220 stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
1221
1222 if (stm32_port->tx_ch)
1223 dma_release_channel(stm32_port->tx_ch);
1224
1225 if (stm32_port->tx_dma_buf)
1226 dma_free_coherent(&pdev->dev,
1227 TX_BUF_L, stm32_port->tx_buf,
1228 stm32_port->tx_dma_buf);
1229
1230 if (stm32_port->wakeirq > 0) {
1231 dev_pm_clear_wake_irq(&pdev->dev);
1232 device_init_wakeup(&pdev->dev, false);
1233 }
1234
1235 clk_disable_unprepare(stm32_port->clk);
1236
1237 err = uart_remove_one_port(&stm32_usart_driver, port);
1238
1239 pm_runtime_disable(&pdev->dev);
1240 pm_runtime_put_noidle(&pdev->dev);
1241
1242 return err;
1243}
1244
1245
1246#ifdef CONFIG_SERIAL_STM32_CONSOLE
1247static void stm32_console_putchar(struct uart_port *port, int ch)
1248{
1249 struct stm32_port *stm32_port = to_stm32_port(port);
1250 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1251
1252 while (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE))
1253 cpu_relax();
1254
1255 writel_relaxed(ch, port->membase + ofs->tdr);
1256}
1257
1258static void stm32_console_write(struct console *co, const char *s, unsigned cnt)
1259{
1260 struct uart_port *port = &stm32_ports[co->index].port;
1261 struct stm32_port *stm32_port = to_stm32_port(port);
1262 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1263 struct stm32_usart_config *cfg = &stm32_port->info->cfg;
1264 unsigned long flags;
1265 u32 old_cr1, new_cr1;
1266 int locked = 1;
1267
1268 local_irq_save(flags);
1269 if (port->sysrq)
1270 locked = 0;
1271 else if (oops_in_progress)
1272 locked = spin_trylock(&port->lock);
1273 else
1274 spin_lock(&port->lock);
1275
1276 /* Save and disable interrupts, enable the transmitter */
1277 old_cr1 = readl_relaxed(port->membase + ofs->cr1);
1278 new_cr1 = old_cr1 & ~USART_CR1_IE_MASK;
1279 new_cr1 |= USART_CR1_TE | BIT(cfg->uart_enable_bit);
1280 writel_relaxed(new_cr1, port->membase + ofs->cr1);
1281
1282 uart_console_write(port, s, cnt, stm32_console_putchar);
1283
1284 /* Restore interrupt state */
1285 writel_relaxed(old_cr1, port->membase + ofs->cr1);
1286
1287 if (locked)
1288 spin_unlock(&port->lock);
1289 local_irq_restore(flags);
1290}
1291
1292static int stm32_console_setup(struct console *co, char *options)
1293{
1294 struct stm32_port *stm32port;
1295 int baud = 9600;
1296 int bits = 8;
1297 int parity = 'n';
1298 int flow = 'n';
1299
1300 if (co->index >= STM32_MAX_PORTS)
1301 return -ENODEV;
1302
1303 stm32port = &stm32_ports[co->index];
1304
1305 /*
1306 * This driver does not support early console initialization
1307 * (use ARM early printk support instead), so we only expect
1308 * this to be called during the uart port registration when the
1309 * driver gets probed and the port should be mapped at that point.
1310 */
1311 if (stm32port->port.mapbase == 0 || stm32port->port.membase == NULL)
1312 return -ENXIO;
1313
1314 if (options)
1315 uart_parse_options(options, &baud, &parity, &bits, &flow);
1316
1317 return uart_set_options(&stm32port->port, co, baud, parity, bits, flow);
1318}
1319
1320static struct console stm32_console = {
1321 .name = STM32_SERIAL_NAME,
1322 .device = uart_console_device,
1323 .write = stm32_console_write,
1324 .setup = stm32_console_setup,
1325 .flags = CON_PRINTBUFFER,
1326 .index = -1,
1327 .data = &stm32_usart_driver,
1328};
1329
1330#define STM32_SERIAL_CONSOLE (&stm32_console)
1331
1332#else
1333#define STM32_SERIAL_CONSOLE NULL
1334#endif /* CONFIG_SERIAL_STM32_CONSOLE */
1335
1336static struct uart_driver stm32_usart_driver = {
1337 .driver_name = DRIVER_NAME,
1338 .dev_name = STM32_SERIAL_NAME,
1339 .major = 0,
1340 .minor = 0,
1341 .nr = STM32_MAX_PORTS,
1342 .cons = STM32_SERIAL_CONSOLE,
1343};
1344
1345static void __maybe_unused stm32_serial_enable_wakeup(struct uart_port *port,
1346 bool enable)
1347{
1348 struct stm32_port *stm32_port = to_stm32_port(port);
1349 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1350 struct stm32_usart_config *cfg = &stm32_port->info->cfg;
1351 u32 val;
1352
1353 if (stm32_port->wakeirq <= 0)
1354 return;
1355
1356 if (enable) {
1357 stm32_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
1358 stm32_set_bits(port, ofs->cr1, USART_CR1_UESM);
1359 val = readl_relaxed(port->membase + ofs->cr3);
1360 val &= ~USART_CR3_WUS_MASK;
1361 /* Enable Wake up interrupt from low power on start bit */
1362 val |= USART_CR3_WUS_START_BIT | USART_CR3_WUFIE;
1363 writel_relaxed(val, port->membase + ofs->cr3);
1364 stm32_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
1365 } else {
1366 stm32_clr_bits(port, ofs->cr1, USART_CR1_UESM);
1367 }
1368}
1369
1370static int __maybe_unused stm32_serial_suspend(struct device *dev)
1371{
1372 struct uart_port *port = dev_get_drvdata(dev);
1373
1374 uart_suspend_port(&stm32_usart_driver, port);
1375
1376 if (device_may_wakeup(dev))
1377 stm32_serial_enable_wakeup(port, true);
1378 else
1379 stm32_serial_enable_wakeup(port, false);
1380
1381 pinctrl_pm_select_sleep_state(dev);
1382
1383 return 0;
1384}
1385
1386static int __maybe_unused stm32_serial_resume(struct device *dev)
1387{
1388 struct uart_port *port = dev_get_drvdata(dev);
1389
1390 pinctrl_pm_select_default_state(dev);
1391
1392 if (device_may_wakeup(dev))
1393 stm32_serial_enable_wakeup(port, false);
1394
1395 return uart_resume_port(&stm32_usart_driver, port);
1396}
1397
1398static int __maybe_unused stm32_serial_runtime_suspend(struct device *dev)
1399{
1400 struct uart_port *port = dev_get_drvdata(dev);
1401 struct stm32_port *stm32port = container_of(port,
1402 struct stm32_port, port);
1403
1404 clk_disable_unprepare(stm32port->clk);
1405
1406 return 0;
1407}
1408
1409static int __maybe_unused stm32_serial_runtime_resume(struct device *dev)
1410{
1411 struct uart_port *port = dev_get_drvdata(dev);
1412 struct stm32_port *stm32port = container_of(port,
1413 struct stm32_port, port);
1414
1415 return clk_prepare_enable(stm32port->clk);
1416}
1417
1418static const struct dev_pm_ops stm32_serial_pm_ops = {
1419 SET_RUNTIME_PM_OPS(stm32_serial_runtime_suspend,
1420 stm32_serial_runtime_resume, NULL)
1421 SET_SYSTEM_SLEEP_PM_OPS(stm32_serial_suspend, stm32_serial_resume)
1422};
1423
1424static struct platform_driver stm32_serial_driver = {
1425 .probe = stm32_serial_probe,
1426 .remove = stm32_serial_remove,
1427 .driver = {
1428 .name = DRIVER_NAME,
1429 .pm = &stm32_serial_pm_ops,
1430 .of_match_table = of_match_ptr(stm32_match),
1431 },
1432};
1433
1434static int __init usart_init(void)
1435{
1436 static char banner[] __initdata = "STM32 USART driver initialized";
1437 int ret;
1438
1439 pr_info("%s\n", banner);
1440
1441 ret = uart_register_driver(&stm32_usart_driver);
1442 if (ret)
1443 return ret;
1444
1445 ret = platform_driver_register(&stm32_serial_driver);
1446 if (ret)
1447 uart_unregister_driver(&stm32_usart_driver);
1448
1449 return ret;
1450}
1451
1452static void __exit usart_exit(void)
1453{
1454 platform_driver_unregister(&stm32_serial_driver);
1455 uart_unregister_driver(&stm32_usart_driver);
1456}
1457
1458module_init(usart_init);
1459module_exit(usart_exit);
1460
1461MODULE_ALIAS("platform:" DRIVER_NAME);
1462MODULE_DESCRIPTION("STMicroelectronics STM32 serial port driver");
1463MODULE_LICENSE("GPL v2");
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) Maxime Coquelin 2015
4 * Copyright (C) STMicroelectronics SA 2017
5 * Authors: Maxime Coquelin <mcoquelin.stm32@gmail.com>
6 * Gerald Baeza <gerald.baeza@foss.st.com>
7 * Erwan Le Ray <erwan.leray@foss.st.com>
8 *
9 * Inspired by st-asc.c from STMicroelectronics (c)
10 */
11
12#include <linux/bitfield.h>
13#include <linux/clk.h>
14#include <linux/console.h>
15#include <linux/delay.h>
16#include <linux/dma-direction.h>
17#include <linux/dmaengine.h>
18#include <linux/dma-mapping.h>
19#include <linux/io.h>
20#include <linux/iopoll.h>
21#include <linux/irq.h>
22#include <linux/module.h>
23#include <linux/of.h>
24#include <linux/of_platform.h>
25#include <linux/pinctrl/consumer.h>
26#include <linux/platform_device.h>
27#include <linux/pm_runtime.h>
28#include <linux/pm_wakeirq.h>
29#include <linux/serial_core.h>
30#include <linux/serial.h>
31#include <linux/spinlock.h>
32#include <linux/sysrq.h>
33#include <linux/tty_flip.h>
34#include <linux/tty.h>
35
36#include "serial_mctrl_gpio.h"
37#include "stm32-usart.h"
38
39
40/* Register offsets */
41static struct stm32_usart_info __maybe_unused stm32f4_info = {
42 .ofs = {
43 .isr = 0x00,
44 .rdr = 0x04,
45 .tdr = 0x04,
46 .brr = 0x08,
47 .cr1 = 0x0c,
48 .cr2 = 0x10,
49 .cr3 = 0x14,
50 .gtpr = 0x18,
51 .rtor = UNDEF_REG,
52 .rqr = UNDEF_REG,
53 .icr = UNDEF_REG,
54 .presc = UNDEF_REG,
55 .hwcfgr1 = UNDEF_REG,
56 },
57 .cfg = {
58 .uart_enable_bit = 13,
59 .has_7bits_data = false,
60 }
61};
62
63static struct stm32_usart_info __maybe_unused stm32f7_info = {
64 .ofs = {
65 .cr1 = 0x00,
66 .cr2 = 0x04,
67 .cr3 = 0x08,
68 .brr = 0x0c,
69 .gtpr = 0x10,
70 .rtor = 0x14,
71 .rqr = 0x18,
72 .isr = 0x1c,
73 .icr = 0x20,
74 .rdr = 0x24,
75 .tdr = 0x28,
76 .presc = UNDEF_REG,
77 .hwcfgr1 = UNDEF_REG,
78 },
79 .cfg = {
80 .uart_enable_bit = 0,
81 .has_7bits_data = true,
82 .has_swap = true,
83 }
84};
85
86static struct stm32_usart_info __maybe_unused stm32h7_info = {
87 .ofs = {
88 .cr1 = 0x00,
89 .cr2 = 0x04,
90 .cr3 = 0x08,
91 .brr = 0x0c,
92 .gtpr = 0x10,
93 .rtor = 0x14,
94 .rqr = 0x18,
95 .isr = 0x1c,
96 .icr = 0x20,
97 .rdr = 0x24,
98 .tdr = 0x28,
99 .presc = 0x2c,
100 .hwcfgr1 = 0x3f0,
101 },
102 .cfg = {
103 .uart_enable_bit = 0,
104 .has_7bits_data = true,
105 .has_swap = true,
106 .has_wakeup = true,
107 .has_fifo = true,
108 }
109};
110
111static void stm32_usart_stop_tx(struct uart_port *port);
112static void stm32_usart_transmit_chars(struct uart_port *port);
113static void __maybe_unused stm32_usart_console_putchar(struct uart_port *port, unsigned char ch);
114
115static inline struct stm32_port *to_stm32_port(struct uart_port *port)
116{
117 return container_of(port, struct stm32_port, port);
118}
119
120static void stm32_usart_set_bits(struct uart_port *port, u32 reg, u32 bits)
121{
122 u32 val;
123
124 val = readl_relaxed(port->membase + reg);
125 val |= bits;
126 writel_relaxed(val, port->membase + reg);
127}
128
129static void stm32_usart_clr_bits(struct uart_port *port, u32 reg, u32 bits)
130{
131 u32 val;
132
133 val = readl_relaxed(port->membase + reg);
134 val &= ~bits;
135 writel_relaxed(val, port->membase + reg);
136}
137
138static unsigned int stm32_usart_tx_empty(struct uart_port *port)
139{
140 struct stm32_port *stm32_port = to_stm32_port(port);
141 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
142
143 if (readl_relaxed(port->membase + ofs->isr) & USART_SR_TC)
144 return TIOCSER_TEMT;
145
146 return 0;
147}
148
149static void stm32_usart_rs485_rts_enable(struct uart_port *port)
150{
151 struct stm32_port *stm32_port = to_stm32_port(port);
152 struct serial_rs485 *rs485conf = &port->rs485;
153
154 if (stm32_port->hw_flow_control ||
155 !(rs485conf->flags & SER_RS485_ENABLED))
156 return;
157
158 if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
159 mctrl_gpio_set(stm32_port->gpios,
160 stm32_port->port.mctrl | TIOCM_RTS);
161 } else {
162 mctrl_gpio_set(stm32_port->gpios,
163 stm32_port->port.mctrl & ~TIOCM_RTS);
164 }
165}
166
167static void stm32_usart_rs485_rts_disable(struct uart_port *port)
168{
169 struct stm32_port *stm32_port = to_stm32_port(port);
170 struct serial_rs485 *rs485conf = &port->rs485;
171
172 if (stm32_port->hw_flow_control ||
173 !(rs485conf->flags & SER_RS485_ENABLED))
174 return;
175
176 if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
177 mctrl_gpio_set(stm32_port->gpios,
178 stm32_port->port.mctrl & ~TIOCM_RTS);
179 } else {
180 mctrl_gpio_set(stm32_port->gpios,
181 stm32_port->port.mctrl | TIOCM_RTS);
182 }
183}
184
185static void stm32_usart_config_reg_rs485(u32 *cr1, u32 *cr3, u32 delay_ADE,
186 u32 delay_DDE, u32 baud)
187{
188 u32 rs485_deat_dedt;
189 u32 rs485_deat_dedt_max = (USART_CR1_DEAT_MASK >> USART_CR1_DEAT_SHIFT);
190 bool over8;
191
192 *cr3 |= USART_CR3_DEM;
193 over8 = *cr1 & USART_CR1_OVER8;
194
195 *cr1 &= ~(USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
196
197 if (over8)
198 rs485_deat_dedt = delay_ADE * baud * 8;
199 else
200 rs485_deat_dedt = delay_ADE * baud * 16;
201
202 rs485_deat_dedt = DIV_ROUND_CLOSEST(rs485_deat_dedt, 1000);
203 rs485_deat_dedt = rs485_deat_dedt > rs485_deat_dedt_max ?
204 rs485_deat_dedt_max : rs485_deat_dedt;
205 rs485_deat_dedt = (rs485_deat_dedt << USART_CR1_DEAT_SHIFT) &
206 USART_CR1_DEAT_MASK;
207 *cr1 |= rs485_deat_dedt;
208
209 if (over8)
210 rs485_deat_dedt = delay_DDE * baud * 8;
211 else
212 rs485_deat_dedt = delay_DDE * baud * 16;
213
214 rs485_deat_dedt = DIV_ROUND_CLOSEST(rs485_deat_dedt, 1000);
215 rs485_deat_dedt = rs485_deat_dedt > rs485_deat_dedt_max ?
216 rs485_deat_dedt_max : rs485_deat_dedt;
217 rs485_deat_dedt = (rs485_deat_dedt << USART_CR1_DEDT_SHIFT) &
218 USART_CR1_DEDT_MASK;
219 *cr1 |= rs485_deat_dedt;
220}
221
222static int stm32_usart_config_rs485(struct uart_port *port, struct ktermios *termios,
223 struct serial_rs485 *rs485conf)
224{
225 struct stm32_port *stm32_port = to_stm32_port(port);
226 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
227 const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
228 u32 usartdiv, baud, cr1, cr3;
229 bool over8;
230
231 stm32_usart_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
232
233 if (rs485conf->flags & SER_RS485_ENABLED) {
234 cr1 = readl_relaxed(port->membase + ofs->cr1);
235 cr3 = readl_relaxed(port->membase + ofs->cr3);
236 usartdiv = readl_relaxed(port->membase + ofs->brr);
237 usartdiv = usartdiv & GENMASK(15, 0);
238 over8 = cr1 & USART_CR1_OVER8;
239
240 if (over8)
241 usartdiv = usartdiv | (usartdiv & GENMASK(4, 0))
242 << USART_BRR_04_R_SHIFT;
243
244 baud = DIV_ROUND_CLOSEST(port->uartclk, usartdiv);
245 stm32_usart_config_reg_rs485(&cr1, &cr3,
246 rs485conf->delay_rts_before_send,
247 rs485conf->delay_rts_after_send,
248 baud);
249
250 if (rs485conf->flags & SER_RS485_RTS_ON_SEND)
251 cr3 &= ~USART_CR3_DEP;
252 else
253 cr3 |= USART_CR3_DEP;
254
255 writel_relaxed(cr3, port->membase + ofs->cr3);
256 writel_relaxed(cr1, port->membase + ofs->cr1);
257
258 if (!port->rs485_rx_during_tx_gpio)
259 rs485conf->flags |= SER_RS485_RX_DURING_TX;
260
261 } else {
262 stm32_usart_clr_bits(port, ofs->cr3,
263 USART_CR3_DEM | USART_CR3_DEP);
264 stm32_usart_clr_bits(port, ofs->cr1,
265 USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
266 }
267
268 stm32_usart_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
269
270 /* Adjust RTS polarity in case it's driven in software */
271 if (stm32_usart_tx_empty(port))
272 stm32_usart_rs485_rts_disable(port);
273 else
274 stm32_usart_rs485_rts_enable(port);
275
276 return 0;
277}
278
279static int stm32_usart_init_rs485(struct uart_port *port,
280 struct platform_device *pdev)
281{
282 struct serial_rs485 *rs485conf = &port->rs485;
283
284 rs485conf->flags = 0;
285 rs485conf->delay_rts_before_send = 0;
286 rs485conf->delay_rts_after_send = 0;
287
288 if (!pdev->dev.of_node)
289 return -ENODEV;
290
291 return uart_get_rs485_mode(port);
292}
293
294static bool stm32_usart_rx_dma_started(struct stm32_port *stm32_port)
295{
296 return stm32_port->rx_ch ? stm32_port->rx_dma_busy : false;
297}
298
299static void stm32_usart_rx_dma_terminate(struct stm32_port *stm32_port)
300{
301 dmaengine_terminate_async(stm32_port->rx_ch);
302 stm32_port->rx_dma_busy = false;
303}
304
305static int stm32_usart_dma_pause_resume(struct stm32_port *stm32_port,
306 struct dma_chan *chan,
307 enum dma_status expected_status,
308 int dmaengine_pause_or_resume(struct dma_chan *),
309 bool stm32_usart_xx_dma_started(struct stm32_port *),
310 void stm32_usart_xx_dma_terminate(struct stm32_port *))
311{
312 struct uart_port *port = &stm32_port->port;
313 enum dma_status dma_status;
314 int ret;
315
316 if (!stm32_usart_xx_dma_started(stm32_port))
317 return -EPERM;
318
319 dma_status = dmaengine_tx_status(chan, chan->cookie, NULL);
320 if (dma_status != expected_status)
321 return -EAGAIN;
322
323 ret = dmaengine_pause_or_resume(chan);
324 if (ret) {
325 dev_err(port->dev, "DMA failed with error code: %d\n", ret);
326 stm32_usart_xx_dma_terminate(stm32_port);
327 }
328 return ret;
329}
330
331static int stm32_usart_rx_dma_pause(struct stm32_port *stm32_port)
332{
333 return stm32_usart_dma_pause_resume(stm32_port, stm32_port->rx_ch,
334 DMA_IN_PROGRESS, dmaengine_pause,
335 stm32_usart_rx_dma_started,
336 stm32_usart_rx_dma_terminate);
337}
338
339static int stm32_usart_rx_dma_resume(struct stm32_port *stm32_port)
340{
341 return stm32_usart_dma_pause_resume(stm32_port, stm32_port->rx_ch,
342 DMA_PAUSED, dmaengine_resume,
343 stm32_usart_rx_dma_started,
344 stm32_usart_rx_dma_terminate);
345}
346
347/* Return true when data is pending (in pio mode), and false when no data is pending. */
348static bool stm32_usart_pending_rx_pio(struct uart_port *port, u32 *sr)
349{
350 struct stm32_port *stm32_port = to_stm32_port(port);
351 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
352
353 *sr = readl_relaxed(port->membase + ofs->isr);
354 /* Get pending characters in RDR or FIFO */
355 if (*sr & USART_SR_RXNE) {
356 /* Get all pending characters from the RDR or the FIFO when using interrupts */
357 if (!stm32_usart_rx_dma_started(stm32_port))
358 return true;
359
360 /* Handle only RX data errors when using DMA */
361 if (*sr & USART_SR_ERR_MASK)
362 return true;
363 }
364
365 return false;
366}
367
368static u8 stm32_usart_get_char_pio(struct uart_port *port)
369{
370 struct stm32_port *stm32_port = to_stm32_port(port);
371 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
372 unsigned long c;
373
374 c = readl_relaxed(port->membase + ofs->rdr);
375 /* Apply RDR data mask */
376 c &= stm32_port->rdr_mask;
377
378 return c;
379}
380
381static unsigned int stm32_usart_receive_chars_pio(struct uart_port *port)
382{
383 struct stm32_port *stm32_port = to_stm32_port(port);
384 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
385 unsigned int size = 0;
386 u32 sr;
387 u8 c, flag;
388
389 while (stm32_usart_pending_rx_pio(port, &sr)) {
390 sr |= USART_SR_DUMMY_RX;
391 flag = TTY_NORMAL;
392
393 /*
394 * Status bits has to be cleared before reading the RDR:
395 * In FIFO mode, reading the RDR will pop the next data
396 * (if any) along with its status bits into the SR.
397 * Not doing so leads to misalignement between RDR and SR,
398 * and clear status bits of the next rx data.
399 *
400 * Clear errors flags for stm32f7 and stm32h7 compatible
401 * devices. On stm32f4 compatible devices, the error bit is
402 * cleared by the sequence [read SR - read DR].
403 */
404 if ((sr & USART_SR_ERR_MASK) && ofs->icr != UNDEF_REG)
405 writel_relaxed(sr & USART_SR_ERR_MASK,
406 port->membase + ofs->icr);
407
408 c = stm32_usart_get_char_pio(port);
409 port->icount.rx++;
410 size++;
411 if (sr & USART_SR_ERR_MASK) {
412 if (sr & USART_SR_ORE) {
413 port->icount.overrun++;
414 } else if (sr & USART_SR_PE) {
415 port->icount.parity++;
416 } else if (sr & USART_SR_FE) {
417 /* Break detection if character is null */
418 if (!c) {
419 port->icount.brk++;
420 if (uart_handle_break(port))
421 continue;
422 } else {
423 port->icount.frame++;
424 }
425 }
426
427 sr &= port->read_status_mask;
428
429 if (sr & USART_SR_PE) {
430 flag = TTY_PARITY;
431 } else if (sr & USART_SR_FE) {
432 if (!c)
433 flag = TTY_BREAK;
434 else
435 flag = TTY_FRAME;
436 }
437 }
438
439 if (uart_prepare_sysrq_char(port, c))
440 continue;
441 uart_insert_char(port, sr, USART_SR_ORE, c, flag);
442 }
443
444 return size;
445}
446
447static void stm32_usart_push_buffer_dma(struct uart_port *port, unsigned int dma_size)
448{
449 struct stm32_port *stm32_port = to_stm32_port(port);
450 struct tty_port *ttyport = &stm32_port->port.state->port;
451 unsigned char *dma_start;
452 int dma_count, i;
453
454 dma_start = stm32_port->rx_buf + (RX_BUF_L - stm32_port->last_res);
455
456 /*
457 * Apply rdr_mask on buffer in order to mask parity bit.
458 * This loop is useless in cs8 mode because DMA copies only
459 * 8 bits and already ignores parity bit.
460 */
461 if (!(stm32_port->rdr_mask == (BIT(8) - 1)))
462 for (i = 0; i < dma_size; i++)
463 *(dma_start + i) &= stm32_port->rdr_mask;
464
465 dma_count = tty_insert_flip_string(ttyport, dma_start, dma_size);
466 port->icount.rx += dma_count;
467 if (dma_count != dma_size)
468 port->icount.buf_overrun++;
469 stm32_port->last_res -= dma_count;
470 if (stm32_port->last_res == 0)
471 stm32_port->last_res = RX_BUF_L;
472}
473
474static unsigned int stm32_usart_receive_chars_dma(struct uart_port *port)
475{
476 struct stm32_port *stm32_port = to_stm32_port(port);
477 unsigned int dma_size, size = 0;
478
479 /* DMA buffer is configured in cyclic mode and handles the rollback of the buffer. */
480 if (stm32_port->rx_dma_state.residue > stm32_port->last_res) {
481 /* Conditional first part: from last_res to end of DMA buffer */
482 dma_size = stm32_port->last_res;
483 stm32_usart_push_buffer_dma(port, dma_size);
484 size = dma_size;
485 }
486
487 dma_size = stm32_port->last_res - stm32_port->rx_dma_state.residue;
488 stm32_usart_push_buffer_dma(port, dma_size);
489 size += dma_size;
490
491 return size;
492}
493
494static unsigned int stm32_usart_receive_chars(struct uart_port *port, bool force_dma_flush)
495{
496 struct stm32_port *stm32_port = to_stm32_port(port);
497 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
498 enum dma_status rx_dma_status;
499 u32 sr;
500 unsigned int size = 0;
501
502 if (stm32_usart_rx_dma_started(stm32_port) || force_dma_flush) {
503 rx_dma_status = dmaengine_tx_status(stm32_port->rx_ch,
504 stm32_port->rx_ch->cookie,
505 &stm32_port->rx_dma_state);
506 if (rx_dma_status == DMA_IN_PROGRESS ||
507 rx_dma_status == DMA_PAUSED) {
508 /* Empty DMA buffer */
509 size = stm32_usart_receive_chars_dma(port);
510 sr = readl_relaxed(port->membase + ofs->isr);
511 if (sr & USART_SR_ERR_MASK) {
512 /* Disable DMA request line */
513 stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAR);
514
515 /* Switch to PIO mode to handle the errors */
516 size += stm32_usart_receive_chars_pio(port);
517
518 /* Switch back to DMA mode */
519 stm32_usart_set_bits(port, ofs->cr3, USART_CR3_DMAR);
520 }
521 } else {
522 /* Disable RX DMA */
523 stm32_usart_rx_dma_terminate(stm32_port);
524 /* Fall back to interrupt mode */
525 dev_dbg(port->dev, "DMA error, fallback to irq mode\n");
526 size = stm32_usart_receive_chars_pio(port);
527 }
528 } else {
529 size = stm32_usart_receive_chars_pio(port);
530 }
531
532 return size;
533}
534
535static void stm32_usart_rx_dma_complete(void *arg)
536{
537 struct uart_port *port = arg;
538 struct tty_port *tport = &port->state->port;
539 unsigned int size;
540 unsigned long flags;
541
542 uart_port_lock_irqsave(port, &flags);
543 size = stm32_usart_receive_chars(port, false);
544 uart_unlock_and_check_sysrq_irqrestore(port, flags);
545 if (size)
546 tty_flip_buffer_push(tport);
547}
548
549static int stm32_usart_rx_dma_start_or_resume(struct uart_port *port)
550{
551 struct stm32_port *stm32_port = to_stm32_port(port);
552 struct dma_async_tx_descriptor *desc;
553 enum dma_status rx_dma_status;
554 int ret;
555
556 if (stm32_port->throttled)
557 return 0;
558
559 if (stm32_port->rx_dma_busy) {
560 rx_dma_status = dmaengine_tx_status(stm32_port->rx_ch,
561 stm32_port->rx_ch->cookie,
562 NULL);
563 if (rx_dma_status == DMA_IN_PROGRESS)
564 return 0;
565
566 if (rx_dma_status == DMA_PAUSED && !stm32_usart_rx_dma_resume(stm32_port))
567 return 0;
568
569 dev_err(port->dev, "DMA failed : status error.\n");
570 stm32_usart_rx_dma_terminate(stm32_port);
571 }
572
573 stm32_port->rx_dma_busy = true;
574
575 stm32_port->last_res = RX_BUF_L;
576 /* Prepare a DMA cyclic transaction */
577 desc = dmaengine_prep_dma_cyclic(stm32_port->rx_ch,
578 stm32_port->rx_dma_buf,
579 RX_BUF_L, RX_BUF_P,
580 DMA_DEV_TO_MEM,
581 DMA_PREP_INTERRUPT);
582 if (!desc) {
583 dev_err(port->dev, "rx dma prep cyclic failed\n");
584 stm32_port->rx_dma_busy = false;
585 return -ENODEV;
586 }
587
588 desc->callback = stm32_usart_rx_dma_complete;
589 desc->callback_param = port;
590
591 /* Push current DMA transaction in the pending queue */
592 ret = dma_submit_error(dmaengine_submit(desc));
593 if (ret) {
594 dmaengine_terminate_sync(stm32_port->rx_ch);
595 stm32_port->rx_dma_busy = false;
596 return ret;
597 }
598
599 /* Issue pending DMA requests */
600 dma_async_issue_pending(stm32_port->rx_ch);
601
602 return 0;
603}
604
605static void stm32_usart_tx_dma_terminate(struct stm32_port *stm32_port)
606{
607 dmaengine_terminate_async(stm32_port->tx_ch);
608 stm32_port->tx_dma_busy = false;
609}
610
611static bool stm32_usart_tx_dma_started(struct stm32_port *stm32_port)
612{
613 /*
614 * We cannot use the function "dmaengine_tx_status" to know the
615 * status of DMA. This function does not show if the "dma complete"
616 * callback of the DMA transaction has been called. So we prefer
617 * to use "tx_dma_busy" flag to prevent dual DMA transaction at the
618 * same time.
619 */
620 return stm32_port->tx_dma_busy;
621}
622
623static int stm32_usart_tx_dma_pause(struct stm32_port *stm32_port)
624{
625 return stm32_usart_dma_pause_resume(stm32_port, stm32_port->tx_ch,
626 DMA_IN_PROGRESS, dmaengine_pause,
627 stm32_usart_tx_dma_started,
628 stm32_usart_tx_dma_terminate);
629}
630
631static int stm32_usart_tx_dma_resume(struct stm32_port *stm32_port)
632{
633 return stm32_usart_dma_pause_resume(stm32_port, stm32_port->tx_ch,
634 DMA_PAUSED, dmaengine_resume,
635 stm32_usart_tx_dma_started,
636 stm32_usart_tx_dma_terminate);
637}
638
639static void stm32_usart_tx_dma_complete(void *arg)
640{
641 struct uart_port *port = arg;
642 struct stm32_port *stm32port = to_stm32_port(port);
643 unsigned long flags;
644
645 stm32_usart_tx_dma_terminate(stm32port);
646
647 /* Let's see if we have pending data to send */
648 uart_port_lock_irqsave(port, &flags);
649 stm32_usart_transmit_chars(port);
650 uart_port_unlock_irqrestore(port, flags);
651}
652
653static void stm32_usart_tx_interrupt_enable(struct uart_port *port)
654{
655 struct stm32_port *stm32_port = to_stm32_port(port);
656 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
657
658 /*
659 * Enables TX FIFO threashold irq when FIFO is enabled,
660 * or TX empty irq when FIFO is disabled
661 */
662 if (stm32_port->fifoen && stm32_port->txftcfg >= 0)
663 stm32_usart_set_bits(port, ofs->cr3, USART_CR3_TXFTIE);
664 else
665 stm32_usart_set_bits(port, ofs->cr1, USART_CR1_TXEIE);
666}
667
668static void stm32_usart_tc_interrupt_enable(struct uart_port *port)
669{
670 struct stm32_port *stm32_port = to_stm32_port(port);
671 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
672
673 stm32_usart_set_bits(port, ofs->cr1, USART_CR1_TCIE);
674}
675
676static void stm32_usart_tx_interrupt_disable(struct uart_port *port)
677{
678 struct stm32_port *stm32_port = to_stm32_port(port);
679 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
680
681 if (stm32_port->fifoen && stm32_port->txftcfg >= 0)
682 stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_TXFTIE);
683 else
684 stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_TXEIE);
685}
686
687static void stm32_usart_tc_interrupt_disable(struct uart_port *port)
688{
689 struct stm32_port *stm32_port = to_stm32_port(port);
690 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
691
692 stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_TCIE);
693}
694
695static void stm32_usart_transmit_chars_pio(struct uart_port *port)
696{
697 struct stm32_port *stm32_port = to_stm32_port(port);
698 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
699 struct circ_buf *xmit = &port->state->xmit;
700
701 while (!uart_circ_empty(xmit)) {
702 /* Check that TDR is empty before filling FIFO */
703 if (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE))
704 break;
705 writel_relaxed(xmit->buf[xmit->tail], port->membase + ofs->tdr);
706 uart_xmit_advance(port, 1);
707 }
708
709 /* rely on TXE irq (mask or unmask) for sending remaining data */
710 if (uart_circ_empty(xmit))
711 stm32_usart_tx_interrupt_disable(port);
712 else
713 stm32_usart_tx_interrupt_enable(port);
714}
715
716static void stm32_usart_transmit_chars_dma(struct uart_port *port)
717{
718 struct stm32_port *stm32port = to_stm32_port(port);
719 struct circ_buf *xmit = &port->state->xmit;
720 struct dma_async_tx_descriptor *desc = NULL;
721 unsigned int count;
722 int ret;
723
724 if (stm32_usart_tx_dma_started(stm32port)) {
725 ret = stm32_usart_tx_dma_resume(stm32port);
726 if (ret < 0 && ret != -EAGAIN)
727 goto fallback_err;
728 return;
729 }
730
731 count = uart_circ_chars_pending(xmit);
732
733 if (count > TX_BUF_L)
734 count = TX_BUF_L;
735
736 if (xmit->tail < xmit->head) {
737 memcpy(&stm32port->tx_buf[0], &xmit->buf[xmit->tail], count);
738 } else {
739 size_t one = UART_XMIT_SIZE - xmit->tail;
740 size_t two;
741
742 if (one > count)
743 one = count;
744 two = count - one;
745
746 memcpy(&stm32port->tx_buf[0], &xmit->buf[xmit->tail], one);
747 if (two)
748 memcpy(&stm32port->tx_buf[one], &xmit->buf[0], two);
749 }
750
751 desc = dmaengine_prep_slave_single(stm32port->tx_ch,
752 stm32port->tx_dma_buf,
753 count,
754 DMA_MEM_TO_DEV,
755 DMA_PREP_INTERRUPT);
756
757 if (!desc)
758 goto fallback_err;
759
760 /*
761 * Set "tx_dma_busy" flag. This flag will be released when
762 * dmaengine_terminate_async will be called. This flag helps
763 * transmit_chars_dma not to start another DMA transaction
764 * if the callback of the previous is not yet called.
765 */
766 stm32port->tx_dma_busy = true;
767
768 desc->callback = stm32_usart_tx_dma_complete;
769 desc->callback_param = port;
770
771 /* Push current DMA TX transaction in the pending queue */
772 /* DMA no yet started, safe to free resources */
773 ret = dma_submit_error(dmaengine_submit(desc));
774 if (ret) {
775 dev_err(port->dev, "DMA failed with error code: %d\n", ret);
776 stm32_usart_tx_dma_terminate(stm32port);
777 goto fallback_err;
778 }
779
780 /* Issue pending DMA TX requests */
781 dma_async_issue_pending(stm32port->tx_ch);
782
783 uart_xmit_advance(port, count);
784
785 return;
786
787fallback_err:
788 stm32_usart_transmit_chars_pio(port);
789}
790
791static void stm32_usart_transmit_chars(struct uart_port *port)
792{
793 struct stm32_port *stm32_port = to_stm32_port(port);
794 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
795 struct circ_buf *xmit = &port->state->xmit;
796 u32 isr;
797 int ret;
798
799 if (!stm32_port->hw_flow_control &&
800 port->rs485.flags & SER_RS485_ENABLED &&
801 (port->x_char ||
802 !(uart_circ_empty(xmit) || uart_tx_stopped(port)))) {
803 stm32_usart_tc_interrupt_disable(port);
804 stm32_usart_rs485_rts_enable(port);
805 }
806
807 if (port->x_char) {
808 /* dma terminate may have been called in case of dma pause failure */
809 stm32_usart_tx_dma_pause(stm32_port);
810
811 /* Check that TDR is empty before filling FIFO */
812 ret =
813 readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr,
814 isr,
815 (isr & USART_SR_TXE),
816 10, 1000);
817 if (ret)
818 dev_warn(port->dev, "1 character may be erased\n");
819
820 writel_relaxed(port->x_char, port->membase + ofs->tdr);
821 port->x_char = 0;
822 port->icount.tx++;
823
824 /* dma terminate may have been called in case of dma resume failure */
825 stm32_usart_tx_dma_resume(stm32_port);
826 return;
827 }
828
829 if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
830 stm32_usart_tx_interrupt_disable(port);
831 return;
832 }
833
834 if (ofs->icr == UNDEF_REG)
835 stm32_usart_clr_bits(port, ofs->isr, USART_SR_TC);
836 else
837 writel_relaxed(USART_ICR_TCCF, port->membase + ofs->icr);
838
839 if (stm32_port->tx_ch)
840 stm32_usart_transmit_chars_dma(port);
841 else
842 stm32_usart_transmit_chars_pio(port);
843
844 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
845 uart_write_wakeup(port);
846
847 if (uart_circ_empty(xmit)) {
848 stm32_usart_tx_interrupt_disable(port);
849 if (!stm32_port->hw_flow_control &&
850 port->rs485.flags & SER_RS485_ENABLED) {
851 stm32_usart_tc_interrupt_enable(port);
852 }
853 }
854}
855
856static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
857{
858 struct uart_port *port = ptr;
859 struct tty_port *tport = &port->state->port;
860 struct stm32_port *stm32_port = to_stm32_port(port);
861 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
862 u32 sr;
863 unsigned int size;
864 irqreturn_t ret = IRQ_NONE;
865
866 sr = readl_relaxed(port->membase + ofs->isr);
867
868 if (!stm32_port->hw_flow_control &&
869 port->rs485.flags & SER_RS485_ENABLED &&
870 (sr & USART_SR_TC)) {
871 stm32_usart_tc_interrupt_disable(port);
872 stm32_usart_rs485_rts_disable(port);
873 ret = IRQ_HANDLED;
874 }
875
876 if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG) {
877 writel_relaxed(USART_ICR_RTOCF,
878 port->membase + ofs->icr);
879 ret = IRQ_HANDLED;
880 }
881
882 if ((sr & USART_SR_WUF) && ofs->icr != UNDEF_REG) {
883 /* Clear wake up flag and disable wake up interrupt */
884 writel_relaxed(USART_ICR_WUCF,
885 port->membase + ofs->icr);
886 stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE);
887 if (irqd_is_wakeup_set(irq_get_irq_data(port->irq)))
888 pm_wakeup_event(tport->tty->dev, 0);
889 ret = IRQ_HANDLED;
890 }
891
892 /*
893 * rx errors in dma mode has to be handled ASAP to avoid overrun as the DMA request
894 * line has been masked by HW and rx data are stacking in FIFO.
895 */
896 if (!stm32_port->throttled) {
897 if (((sr & USART_SR_RXNE) && !stm32_usart_rx_dma_started(stm32_port)) ||
898 ((sr & USART_SR_ERR_MASK) && stm32_usart_rx_dma_started(stm32_port))) {
899 uart_port_lock(port);
900 size = stm32_usart_receive_chars(port, false);
901 uart_unlock_and_check_sysrq(port);
902 if (size)
903 tty_flip_buffer_push(tport);
904 ret = IRQ_HANDLED;
905 }
906 }
907
908 if ((sr & USART_SR_TXE) && !(stm32_port->tx_ch)) {
909 uart_port_lock(port);
910 stm32_usart_transmit_chars(port);
911 uart_port_unlock(port);
912 ret = IRQ_HANDLED;
913 }
914
915 /* Receiver timeout irq for DMA RX */
916 if (stm32_usart_rx_dma_started(stm32_port) && !stm32_port->throttled) {
917 uart_port_lock(port);
918 size = stm32_usart_receive_chars(port, false);
919 uart_unlock_and_check_sysrq(port);
920 if (size)
921 tty_flip_buffer_push(tport);
922 ret = IRQ_HANDLED;
923 }
924
925 return ret;
926}
927
928static void stm32_usart_set_mctrl(struct uart_port *port, unsigned int mctrl)
929{
930 struct stm32_port *stm32_port = to_stm32_port(port);
931 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
932
933 if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS))
934 stm32_usart_set_bits(port, ofs->cr3, USART_CR3_RTSE);
935 else
936 stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_RTSE);
937
938 mctrl_gpio_set(stm32_port->gpios, mctrl);
939}
940
941static unsigned int stm32_usart_get_mctrl(struct uart_port *port)
942{
943 struct stm32_port *stm32_port = to_stm32_port(port);
944 unsigned int ret;
945
946 /* This routine is used to get signals of: DCD, DSR, RI, and CTS */
947 ret = TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
948
949 return mctrl_gpio_get(stm32_port->gpios, &ret);
950}
951
952static void stm32_usart_enable_ms(struct uart_port *port)
953{
954 mctrl_gpio_enable_ms(to_stm32_port(port)->gpios);
955}
956
957static void stm32_usart_disable_ms(struct uart_port *port)
958{
959 mctrl_gpio_disable_ms(to_stm32_port(port)->gpios);
960}
961
962/* Transmit stop */
963static void stm32_usart_stop_tx(struct uart_port *port)
964{
965 struct stm32_port *stm32_port = to_stm32_port(port);
966
967 stm32_usart_tx_interrupt_disable(port);
968
969 /* dma terminate may have been called in case of dma pause failure */
970 stm32_usart_tx_dma_pause(stm32_port);
971
972 stm32_usart_rs485_rts_disable(port);
973}
974
975/* There are probably characters waiting to be transmitted. */
976static void stm32_usart_start_tx(struct uart_port *port)
977{
978 struct circ_buf *xmit = &port->state->xmit;
979
980 if (uart_circ_empty(xmit) && !port->x_char) {
981 stm32_usart_rs485_rts_disable(port);
982 return;
983 }
984
985 stm32_usart_rs485_rts_enable(port);
986
987 stm32_usart_transmit_chars(port);
988}
989
990/* Flush the transmit buffer. */
991static void stm32_usart_flush_buffer(struct uart_port *port)
992{
993 struct stm32_port *stm32_port = to_stm32_port(port);
994
995 if (stm32_port->tx_ch)
996 stm32_usart_tx_dma_terminate(stm32_port);
997}
998
999/* Throttle the remote when input buffer is about to overflow. */
1000static void stm32_usart_throttle(struct uart_port *port)
1001{
1002 struct stm32_port *stm32_port = to_stm32_port(port);
1003 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1004 unsigned long flags;
1005
1006 uart_port_lock_irqsave(port, &flags);
1007
1008 /*
1009 * Pause DMA transfer, so the RX data gets queued into the FIFO.
1010 * Hardware flow control is triggered when RX FIFO is full.
1011 */
1012 stm32_usart_rx_dma_pause(stm32_port);
1013
1014 stm32_usart_clr_bits(port, ofs->cr1, stm32_port->cr1_irq);
1015 if (stm32_port->cr3_irq)
1016 stm32_usart_clr_bits(port, ofs->cr3, stm32_port->cr3_irq);
1017
1018 stm32_port->throttled = true;
1019 uart_port_unlock_irqrestore(port, flags);
1020}
1021
1022/* Unthrottle the remote, the input buffer can now accept data. */
1023static void stm32_usart_unthrottle(struct uart_port *port)
1024{
1025 struct stm32_port *stm32_port = to_stm32_port(port);
1026 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1027 unsigned long flags;
1028
1029 uart_port_lock_irqsave(port, &flags);
1030 stm32_usart_set_bits(port, ofs->cr1, stm32_port->cr1_irq);
1031 if (stm32_port->cr3_irq)
1032 stm32_usart_set_bits(port, ofs->cr3, stm32_port->cr3_irq);
1033
1034 stm32_port->throttled = false;
1035
1036 /*
1037 * Switch back to DMA mode (resume DMA).
1038 * Hardware flow control is stopped when FIFO is not full any more.
1039 */
1040 if (stm32_port->rx_ch)
1041 stm32_usart_rx_dma_start_or_resume(port);
1042
1043 uart_port_unlock_irqrestore(port, flags);
1044}
1045
1046/* Receive stop */
1047static void stm32_usart_stop_rx(struct uart_port *port)
1048{
1049 struct stm32_port *stm32_port = to_stm32_port(port);
1050 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1051
1052 /* Disable DMA request line. */
1053 stm32_usart_rx_dma_pause(stm32_port);
1054
1055 stm32_usart_clr_bits(port, ofs->cr1, stm32_port->cr1_irq);
1056 if (stm32_port->cr3_irq)
1057 stm32_usart_clr_bits(port, ofs->cr3, stm32_port->cr3_irq);
1058}
1059
1060static void stm32_usart_break_ctl(struct uart_port *port, int break_state)
1061{
1062 struct stm32_port *stm32_port = to_stm32_port(port);
1063 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1064 unsigned long flags;
1065
1066 spin_lock_irqsave(&port->lock, flags);
1067
1068 if (break_state)
1069 stm32_usart_set_bits(port, ofs->rqr, USART_RQR_SBKRQ);
1070 else
1071 stm32_usart_clr_bits(port, ofs->rqr, USART_RQR_SBKRQ);
1072
1073 spin_unlock_irqrestore(&port->lock, flags);
1074}
1075
1076static int stm32_usart_startup(struct uart_port *port)
1077{
1078 struct stm32_port *stm32_port = to_stm32_port(port);
1079 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1080 const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
1081 const char *name = to_platform_device(port->dev)->name;
1082 u32 val;
1083 int ret;
1084
1085 ret = request_irq(port->irq, stm32_usart_interrupt,
1086 IRQF_NO_SUSPEND, name, port);
1087 if (ret)
1088 return ret;
1089
1090 if (stm32_port->swap) {
1091 val = readl_relaxed(port->membase + ofs->cr2);
1092 val |= USART_CR2_SWAP;
1093 writel_relaxed(val, port->membase + ofs->cr2);
1094 }
1095 stm32_port->throttled = false;
1096
1097 /* RX FIFO Flush */
1098 if (ofs->rqr != UNDEF_REG)
1099 writel_relaxed(USART_RQR_RXFRQ, port->membase + ofs->rqr);
1100
1101 if (stm32_port->rx_ch) {
1102 ret = stm32_usart_rx_dma_start_or_resume(port);
1103 if (ret) {
1104 free_irq(port->irq, port);
1105 return ret;
1106 }
1107 }
1108
1109 /* RX enabling */
1110 val = stm32_port->cr1_irq | USART_CR1_RE | BIT(cfg->uart_enable_bit);
1111 stm32_usart_set_bits(port, ofs->cr1, val);
1112
1113 return 0;
1114}
1115
1116static void stm32_usart_shutdown(struct uart_port *port)
1117{
1118 struct stm32_port *stm32_port = to_stm32_port(port);
1119 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1120 const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
1121 u32 val, isr;
1122 int ret;
1123
1124 if (stm32_usart_tx_dma_started(stm32_port))
1125 stm32_usart_tx_dma_terminate(stm32_port);
1126
1127 if (stm32_port->tx_ch)
1128 stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
1129
1130 /* Disable modem control interrupts */
1131 stm32_usart_disable_ms(port);
1132
1133 val = USART_CR1_TXEIE | USART_CR1_TE;
1134 val |= stm32_port->cr1_irq | USART_CR1_RE;
1135 val |= BIT(cfg->uart_enable_bit);
1136 if (stm32_port->fifoen)
1137 val |= USART_CR1_FIFOEN;
1138
1139 ret = readl_relaxed_poll_timeout(port->membase + ofs->isr,
1140 isr, (isr & USART_SR_TC),
1141 10, 100000);
1142
1143 /* Send the TC error message only when ISR_TC is not set */
1144 if (ret)
1145 dev_err(port->dev, "Transmission is not complete\n");
1146
1147 /* Disable RX DMA. */
1148 if (stm32_port->rx_ch) {
1149 stm32_usart_rx_dma_terminate(stm32_port);
1150 dmaengine_synchronize(stm32_port->rx_ch);
1151 }
1152
1153 /* flush RX & TX FIFO */
1154 if (ofs->rqr != UNDEF_REG)
1155 writel_relaxed(USART_RQR_TXFRQ | USART_RQR_RXFRQ,
1156 port->membase + ofs->rqr);
1157
1158 stm32_usart_clr_bits(port, ofs->cr1, val);
1159
1160 free_irq(port->irq, port);
1161}
1162
1163static const unsigned int stm32_usart_presc_val[] = {1, 2, 4, 6, 8, 10, 12, 16, 32, 64, 128, 256};
1164
1165static void stm32_usart_set_termios(struct uart_port *port,
1166 struct ktermios *termios,
1167 const struct ktermios *old)
1168{
1169 struct stm32_port *stm32_port = to_stm32_port(port);
1170 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1171 const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
1172 struct serial_rs485 *rs485conf = &port->rs485;
1173 unsigned int baud, bits, uart_clk, uart_clk_pres;
1174 u32 usartdiv, mantissa, fraction, oversampling;
1175 tcflag_t cflag = termios->c_cflag;
1176 u32 cr1, cr2, cr3, isr, brr, presc;
1177 unsigned long flags;
1178 int ret;
1179
1180 if (!stm32_port->hw_flow_control)
1181 cflag &= ~CRTSCTS;
1182
1183 uart_clk = clk_get_rate(stm32_port->clk);
1184
1185 baud = uart_get_baud_rate(port, termios, old, 0, uart_clk / 8);
1186
1187 uart_port_lock_irqsave(port, &flags);
1188
1189 ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr,
1190 isr,
1191 (isr & USART_SR_TC),
1192 10, 100000);
1193
1194 /* Send the TC error message only when ISR_TC is not set. */
1195 if (ret)
1196 dev_err(port->dev, "Transmission is not complete\n");
1197
1198 /* Stop serial port and reset value */
1199 writel_relaxed(0, port->membase + ofs->cr1);
1200
1201 /* flush RX & TX FIFO */
1202 if (ofs->rqr != UNDEF_REG)
1203 writel_relaxed(USART_RQR_TXFRQ | USART_RQR_RXFRQ,
1204 port->membase + ofs->rqr);
1205
1206 cr1 = USART_CR1_TE | USART_CR1_RE;
1207 if (stm32_port->fifoen)
1208 cr1 |= USART_CR1_FIFOEN;
1209 cr2 = stm32_port->swap ? USART_CR2_SWAP : 0;
1210
1211 /* Tx and RX FIFO configuration */
1212 cr3 = readl_relaxed(port->membase + ofs->cr3);
1213 cr3 &= USART_CR3_TXFTIE | USART_CR3_RXFTIE;
1214 if (stm32_port->fifoen) {
1215 if (stm32_port->txftcfg >= 0)
1216 cr3 |= stm32_port->txftcfg << USART_CR3_TXFTCFG_SHIFT;
1217 if (stm32_port->rxftcfg >= 0)
1218 cr3 |= stm32_port->rxftcfg << USART_CR3_RXFTCFG_SHIFT;
1219 }
1220
1221 if (cflag & CSTOPB)
1222 cr2 |= USART_CR2_STOP_2B;
1223
1224 bits = tty_get_char_size(cflag);
1225 stm32_port->rdr_mask = (BIT(bits) - 1);
1226
1227 if (cflag & PARENB) {
1228 bits++;
1229 cr1 |= USART_CR1_PCE;
1230 }
1231
1232 /*
1233 * Word length configuration:
1234 * CS8 + parity, 9 bits word aka [M1:M0] = 0b01
1235 * CS7 or (CS6 + parity), 7 bits word aka [M1:M0] = 0b10
1236 * CS8 or (CS7 + parity), 8 bits word aka [M1:M0] = 0b00
1237 * M0 and M1 already cleared by cr1 initialization.
1238 */
1239 if (bits == 9) {
1240 cr1 |= USART_CR1_M0;
1241 } else if ((bits == 7) && cfg->has_7bits_data) {
1242 cr1 |= USART_CR1_M1;
1243 } else if (bits != 8) {
1244 dev_dbg(port->dev, "Unsupported data bits config: %u bits\n"
1245 , bits);
1246 cflag &= ~CSIZE;
1247 cflag |= CS8;
1248 termios->c_cflag = cflag;
1249 bits = 8;
1250 if (cflag & PARENB) {
1251 bits++;
1252 cr1 |= USART_CR1_M0;
1253 }
1254 }
1255
1256 if (ofs->rtor != UNDEF_REG && (stm32_port->rx_ch ||
1257 (stm32_port->fifoen &&
1258 stm32_port->rxftcfg >= 0))) {
1259 if (cflag & CSTOPB)
1260 bits = bits + 3; /* 1 start bit + 2 stop bits */
1261 else
1262 bits = bits + 2; /* 1 start bit + 1 stop bit */
1263
1264 /* RX timeout irq to occur after last stop bit + bits */
1265 stm32_port->cr1_irq = USART_CR1_RTOIE;
1266 writel_relaxed(bits, port->membase + ofs->rtor);
1267 cr2 |= USART_CR2_RTOEN;
1268 /*
1269 * Enable fifo threshold irq in two cases, either when there is no DMA, or when
1270 * wake up over usart, from low power until the DMA gets re-enabled by resume.
1271 */
1272 stm32_port->cr3_irq = USART_CR3_RXFTIE;
1273 }
1274
1275 cr1 |= stm32_port->cr1_irq;
1276 cr3 |= stm32_port->cr3_irq;
1277
1278 if (cflag & PARODD)
1279 cr1 |= USART_CR1_PS;
1280
1281 port->status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS);
1282 if (cflag & CRTSCTS) {
1283 port->status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
1284 cr3 |= USART_CR3_CTSE | USART_CR3_RTSE;
1285 }
1286
1287 for (presc = 0; presc <= USART_PRESC_MAX; presc++) {
1288 uart_clk_pres = DIV_ROUND_CLOSEST(uart_clk, stm32_usart_presc_val[presc]);
1289 usartdiv = DIV_ROUND_CLOSEST(uart_clk_pres, baud);
1290
1291 /*
1292 * The USART supports 16 or 8 times oversampling.
1293 * By default we prefer 16 times oversampling, so that the receiver
1294 * has a better tolerance to clock deviations.
1295 * 8 times oversampling is only used to achieve higher speeds.
1296 */
1297 if (usartdiv < 16) {
1298 oversampling = 8;
1299 cr1 |= USART_CR1_OVER8;
1300 stm32_usart_set_bits(port, ofs->cr1, USART_CR1_OVER8);
1301 } else {
1302 oversampling = 16;
1303 cr1 &= ~USART_CR1_OVER8;
1304 stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_OVER8);
1305 }
1306
1307 mantissa = (usartdiv / oversampling) << USART_BRR_DIV_M_SHIFT;
1308 fraction = usartdiv % oversampling;
1309 brr = mantissa | fraction;
1310
1311 if (FIELD_FIT(USART_BRR_MASK, brr)) {
1312 if (ofs->presc != UNDEF_REG) {
1313 port->uartclk = uart_clk_pres;
1314 writel_relaxed(presc, port->membase + ofs->presc);
1315 } else if (presc) {
1316 /* We need a prescaler but we don't have it (STM32F4, STM32F7) */
1317 dev_err(port->dev,
1318 "unable to set baudrate, input clock is too high");
1319 }
1320 break;
1321 } else if (presc == USART_PRESC_MAX) {
1322 /* Even with prescaler and brr at max value we can't set baudrate */
1323 dev_err(port->dev, "unable to set baudrate, input clock is too high");
1324 break;
1325 }
1326 }
1327
1328 writel_relaxed(brr, port->membase + ofs->brr);
1329
1330 uart_update_timeout(port, cflag, baud);
1331
1332 port->read_status_mask = USART_SR_ORE;
1333 if (termios->c_iflag & INPCK)
1334 port->read_status_mask |= USART_SR_PE | USART_SR_FE;
1335 if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
1336 port->read_status_mask |= USART_SR_FE;
1337
1338 /* Characters to ignore */
1339 port->ignore_status_mask = 0;
1340 if (termios->c_iflag & IGNPAR)
1341 port->ignore_status_mask = USART_SR_PE | USART_SR_FE;
1342 if (termios->c_iflag & IGNBRK) {
1343 port->ignore_status_mask |= USART_SR_FE;
1344 /*
1345 * If we're ignoring parity and break indicators,
1346 * ignore overruns too (for real raw support).
1347 */
1348 if (termios->c_iflag & IGNPAR)
1349 port->ignore_status_mask |= USART_SR_ORE;
1350 }
1351
1352 /* Ignore all characters if CREAD is not set */
1353 if ((termios->c_cflag & CREAD) == 0)
1354 port->ignore_status_mask |= USART_SR_DUMMY_RX;
1355
1356 if (stm32_port->rx_ch) {
1357 /*
1358 * Setup DMA to collect only valid data and enable error irqs.
1359 * This also enables break reception when using DMA.
1360 */
1361 cr1 |= USART_CR1_PEIE;
1362 cr3 |= USART_CR3_EIE;
1363 cr3 |= USART_CR3_DMAR;
1364 cr3 |= USART_CR3_DDRE;
1365 }
1366
1367 if (stm32_port->tx_ch)
1368 cr3 |= USART_CR3_DMAT;
1369
1370 if (rs485conf->flags & SER_RS485_ENABLED) {
1371 stm32_usart_config_reg_rs485(&cr1, &cr3,
1372 rs485conf->delay_rts_before_send,
1373 rs485conf->delay_rts_after_send,
1374 baud);
1375 if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
1376 cr3 &= ~USART_CR3_DEP;
1377 rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
1378 } else {
1379 cr3 |= USART_CR3_DEP;
1380 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
1381 }
1382
1383 } else {
1384 cr3 &= ~(USART_CR3_DEM | USART_CR3_DEP);
1385 cr1 &= ~(USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
1386 }
1387
1388 /* Configure wake up from low power on start bit detection */
1389 if (stm32_port->wakeup_src) {
1390 cr3 &= ~USART_CR3_WUS_MASK;
1391 cr3 |= USART_CR3_WUS_START_BIT;
1392 }
1393
1394 writel_relaxed(cr3, port->membase + ofs->cr3);
1395 writel_relaxed(cr2, port->membase + ofs->cr2);
1396 writel_relaxed(cr1, port->membase + ofs->cr1);
1397
1398 stm32_usart_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
1399 uart_port_unlock_irqrestore(port, flags);
1400
1401 /* Handle modem control interrupts */
1402 if (UART_ENABLE_MS(port, termios->c_cflag))
1403 stm32_usart_enable_ms(port);
1404 else
1405 stm32_usart_disable_ms(port);
1406}
1407
1408static const char *stm32_usart_type(struct uart_port *port)
1409{
1410 return (port->type == PORT_STM32) ? DRIVER_NAME : NULL;
1411}
1412
1413static void stm32_usart_release_port(struct uart_port *port)
1414{
1415}
1416
1417static int stm32_usart_request_port(struct uart_port *port)
1418{
1419 return 0;
1420}
1421
1422static void stm32_usart_config_port(struct uart_port *port, int flags)
1423{
1424 if (flags & UART_CONFIG_TYPE)
1425 port->type = PORT_STM32;
1426}
1427
1428static int
1429stm32_usart_verify_port(struct uart_port *port, struct serial_struct *ser)
1430{
1431 /* No user changeable parameters */
1432 return -EINVAL;
1433}
1434
1435static void stm32_usart_pm(struct uart_port *port, unsigned int state,
1436 unsigned int oldstate)
1437{
1438 struct stm32_port *stm32port = container_of(port,
1439 struct stm32_port, port);
1440 const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
1441 const struct stm32_usart_config *cfg = &stm32port->info->cfg;
1442 unsigned long flags;
1443
1444 switch (state) {
1445 case UART_PM_STATE_ON:
1446 pm_runtime_get_sync(port->dev);
1447 break;
1448 case UART_PM_STATE_OFF:
1449 uart_port_lock_irqsave(port, &flags);
1450 stm32_usart_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
1451 uart_port_unlock_irqrestore(port, flags);
1452 pm_runtime_put_sync(port->dev);
1453 break;
1454 }
1455}
1456
1457#if defined(CONFIG_CONSOLE_POLL)
1458
1459 /* Callbacks for characters polling in debug context (i.e. KGDB). */
1460static int stm32_usart_poll_init(struct uart_port *port)
1461{
1462 struct stm32_port *stm32_port = to_stm32_port(port);
1463
1464 return clk_prepare_enable(stm32_port->clk);
1465}
1466
1467static int stm32_usart_poll_get_char(struct uart_port *port)
1468{
1469 struct stm32_port *stm32_port = to_stm32_port(port);
1470 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1471
1472 if (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_RXNE))
1473 return NO_POLL_CHAR;
1474
1475 return readl_relaxed(port->membase + ofs->rdr) & stm32_port->rdr_mask;
1476}
1477
1478static void stm32_usart_poll_put_char(struct uart_port *port, unsigned char ch)
1479{
1480 stm32_usart_console_putchar(port, ch);
1481}
1482#endif /* CONFIG_CONSOLE_POLL */
1483
1484static const struct uart_ops stm32_uart_ops = {
1485 .tx_empty = stm32_usart_tx_empty,
1486 .set_mctrl = stm32_usart_set_mctrl,
1487 .get_mctrl = stm32_usart_get_mctrl,
1488 .stop_tx = stm32_usart_stop_tx,
1489 .start_tx = stm32_usart_start_tx,
1490 .throttle = stm32_usart_throttle,
1491 .unthrottle = stm32_usart_unthrottle,
1492 .stop_rx = stm32_usart_stop_rx,
1493 .enable_ms = stm32_usart_enable_ms,
1494 .break_ctl = stm32_usart_break_ctl,
1495 .startup = stm32_usart_startup,
1496 .shutdown = stm32_usart_shutdown,
1497 .flush_buffer = stm32_usart_flush_buffer,
1498 .set_termios = stm32_usart_set_termios,
1499 .pm = stm32_usart_pm,
1500 .type = stm32_usart_type,
1501 .release_port = stm32_usart_release_port,
1502 .request_port = stm32_usart_request_port,
1503 .config_port = stm32_usart_config_port,
1504 .verify_port = stm32_usart_verify_port,
1505#if defined(CONFIG_CONSOLE_POLL)
1506 .poll_init = stm32_usart_poll_init,
1507 .poll_get_char = stm32_usart_poll_get_char,
1508 .poll_put_char = stm32_usart_poll_put_char,
1509#endif /* CONFIG_CONSOLE_POLL */
1510};
1511
1512struct stm32_usart_thresh_ratio {
1513 int mul;
1514 int div;
1515};
1516
1517static const struct stm32_usart_thresh_ratio stm32h7_usart_fifo_thresh_cfg[] = {
1518 {1, 8}, {1, 4}, {1, 2}, {3, 4}, {7, 8}, {1, 1} };
1519
1520static int stm32_usart_get_thresh_value(u32 fifo_size, int index)
1521{
1522 return fifo_size * stm32h7_usart_fifo_thresh_cfg[index].mul /
1523 stm32h7_usart_fifo_thresh_cfg[index].div;
1524}
1525
1526static int stm32_usart_get_ftcfg(struct platform_device *pdev, struct stm32_port *stm32port,
1527 const char *p, int *ftcfg)
1528{
1529 const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
1530 u32 bytes, i, cfg8;
1531 int fifo_size;
1532
1533 if (WARN_ON(ofs->hwcfgr1 == UNDEF_REG))
1534 return 1;
1535
1536 cfg8 = FIELD_GET(USART_HWCFGR1_CFG8,
1537 readl_relaxed(stm32port->port.membase + ofs->hwcfgr1));
1538
1539 /* On STM32H7, hwcfgr is not present, so returned value will be 0 */
1540 fifo_size = cfg8 ? 1 << cfg8 : STM32H7_USART_FIFO_SIZE;
1541
1542 /* DT option to get RX & TX FIFO threshold (default to half fifo size) */
1543 if (of_property_read_u32(pdev->dev.of_node, p, &bytes))
1544 bytes = fifo_size / 2;
1545
1546 if (bytes < stm32_usart_get_thresh_value(fifo_size, 0)) {
1547 *ftcfg = -EINVAL;
1548 return fifo_size;
1549 }
1550
1551 for (i = 0; i < ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg); i++) {
1552 if (stm32_usart_get_thresh_value(fifo_size, i) >= bytes)
1553 break;
1554 }
1555 if (i >= ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg))
1556 i = ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg) - 1;
1557
1558 dev_dbg(&pdev->dev, "%s set to %d/%d bytes\n", p,
1559 stm32_usart_get_thresh_value(fifo_size, i), fifo_size);
1560
1561 *ftcfg = i;
1562 return fifo_size;
1563}
1564
1565static void stm32_usart_deinit_port(struct stm32_port *stm32port)
1566{
1567 clk_disable_unprepare(stm32port->clk);
1568}
1569
1570static const struct serial_rs485 stm32_rs485_supported = {
1571 .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND |
1572 SER_RS485_RX_DURING_TX,
1573 .delay_rts_before_send = 1,
1574 .delay_rts_after_send = 1,
1575};
1576
1577static int stm32_usart_init_port(struct stm32_port *stm32port,
1578 struct platform_device *pdev)
1579{
1580 struct uart_port *port = &stm32port->port;
1581 struct resource *res;
1582 int ret, irq;
1583
1584 irq = platform_get_irq(pdev, 0);
1585 if (irq < 0)
1586 return irq;
1587
1588 port->iotype = UPIO_MEM;
1589 port->flags = UPF_BOOT_AUTOCONF;
1590 port->ops = &stm32_uart_ops;
1591 port->dev = &pdev->dev;
1592 port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_STM32_CONSOLE);
1593 port->irq = irq;
1594 port->rs485_config = stm32_usart_config_rs485;
1595 port->rs485_supported = stm32_rs485_supported;
1596
1597 ret = stm32_usart_init_rs485(port, pdev);
1598 if (ret)
1599 return ret;
1600
1601 stm32port->wakeup_src = stm32port->info->cfg.has_wakeup &&
1602 of_property_read_bool(pdev->dev.of_node, "wakeup-source");
1603
1604 stm32port->swap = stm32port->info->cfg.has_swap &&
1605 of_property_read_bool(pdev->dev.of_node, "rx-tx-swap");
1606
1607 port->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
1608 if (IS_ERR(port->membase))
1609 return PTR_ERR(port->membase);
1610 port->mapbase = res->start;
1611
1612 spin_lock_init(&port->lock);
1613
1614 stm32port->clk = devm_clk_get(&pdev->dev, NULL);
1615 if (IS_ERR(stm32port->clk))
1616 return PTR_ERR(stm32port->clk);
1617
1618 /* Ensure that clk rate is correct by enabling the clk */
1619 ret = clk_prepare_enable(stm32port->clk);
1620 if (ret)
1621 return ret;
1622
1623 stm32port->port.uartclk = clk_get_rate(stm32port->clk);
1624 if (!stm32port->port.uartclk) {
1625 ret = -EINVAL;
1626 goto err_clk;
1627 }
1628
1629 stm32port->fifoen = stm32port->info->cfg.has_fifo;
1630 if (stm32port->fifoen) {
1631 stm32_usart_get_ftcfg(pdev, stm32port, "rx-threshold", &stm32port->rxftcfg);
1632 port->fifosize = stm32_usart_get_ftcfg(pdev, stm32port, "tx-threshold",
1633 &stm32port->txftcfg);
1634 } else {
1635 port->fifosize = 1;
1636 }
1637
1638 stm32port->gpios = mctrl_gpio_init(&stm32port->port, 0);
1639 if (IS_ERR(stm32port->gpios)) {
1640 ret = PTR_ERR(stm32port->gpios);
1641 goto err_clk;
1642 }
1643
1644 /*
1645 * Both CTS/RTS gpios and "st,hw-flow-ctrl" (deprecated) or "uart-has-rtscts"
1646 * properties should not be specified.
1647 */
1648 if (stm32port->hw_flow_control) {
1649 if (mctrl_gpio_to_gpiod(stm32port->gpios, UART_GPIO_CTS) ||
1650 mctrl_gpio_to_gpiod(stm32port->gpios, UART_GPIO_RTS)) {
1651 dev_err(&pdev->dev, "Conflicting RTS/CTS config\n");
1652 ret = -EINVAL;
1653 goto err_clk;
1654 }
1655 }
1656
1657 return ret;
1658
1659err_clk:
1660 clk_disable_unprepare(stm32port->clk);
1661
1662 return ret;
1663}
1664
1665static struct stm32_port *stm32_usart_of_get_port(struct platform_device *pdev)
1666{
1667 struct device_node *np = pdev->dev.of_node;
1668 int id;
1669
1670 if (!np)
1671 return NULL;
1672
1673 id = of_alias_get_id(np, "serial");
1674 if (id < 0) {
1675 dev_err(&pdev->dev, "failed to get alias id, errno %d\n", id);
1676 return NULL;
1677 }
1678
1679 if (WARN_ON(id >= STM32_MAX_PORTS))
1680 return NULL;
1681
1682 stm32_ports[id].hw_flow_control =
1683 of_property_read_bool (np, "st,hw-flow-ctrl") /*deprecated*/ ||
1684 of_property_read_bool (np, "uart-has-rtscts");
1685 stm32_ports[id].port.line = id;
1686 stm32_ports[id].cr1_irq = USART_CR1_RXNEIE;
1687 stm32_ports[id].cr3_irq = 0;
1688 stm32_ports[id].last_res = RX_BUF_L;
1689 return &stm32_ports[id];
1690}
1691
1692#ifdef CONFIG_OF
1693static const struct of_device_id stm32_match[] = {
1694 { .compatible = "st,stm32-uart", .data = &stm32f4_info},
1695 { .compatible = "st,stm32f7-uart", .data = &stm32f7_info},
1696 { .compatible = "st,stm32h7-uart", .data = &stm32h7_info},
1697 {},
1698};
1699
1700MODULE_DEVICE_TABLE(of, stm32_match);
1701#endif
1702
1703static void stm32_usart_of_dma_rx_remove(struct stm32_port *stm32port,
1704 struct platform_device *pdev)
1705{
1706 if (stm32port->rx_buf)
1707 dma_free_coherent(&pdev->dev, RX_BUF_L, stm32port->rx_buf,
1708 stm32port->rx_dma_buf);
1709}
1710
1711static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port,
1712 struct platform_device *pdev)
1713{
1714 const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
1715 struct uart_port *port = &stm32port->port;
1716 struct device *dev = &pdev->dev;
1717 struct dma_slave_config config;
1718 int ret;
1719
1720 stm32port->rx_buf = dma_alloc_coherent(dev, RX_BUF_L,
1721 &stm32port->rx_dma_buf,
1722 GFP_KERNEL);
1723 if (!stm32port->rx_buf)
1724 return -ENOMEM;
1725
1726 /* Configure DMA channel */
1727 memset(&config, 0, sizeof(config));
1728 config.src_addr = port->mapbase + ofs->rdr;
1729 config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1730
1731 ret = dmaengine_slave_config(stm32port->rx_ch, &config);
1732 if (ret < 0) {
1733 dev_err(dev, "rx dma channel config failed\n");
1734 stm32_usart_of_dma_rx_remove(stm32port, pdev);
1735 return ret;
1736 }
1737
1738 return 0;
1739}
1740
1741static void stm32_usart_of_dma_tx_remove(struct stm32_port *stm32port,
1742 struct platform_device *pdev)
1743{
1744 if (stm32port->tx_buf)
1745 dma_free_coherent(&pdev->dev, TX_BUF_L, stm32port->tx_buf,
1746 stm32port->tx_dma_buf);
1747}
1748
1749static int stm32_usart_of_dma_tx_probe(struct stm32_port *stm32port,
1750 struct platform_device *pdev)
1751{
1752 const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
1753 struct uart_port *port = &stm32port->port;
1754 struct device *dev = &pdev->dev;
1755 struct dma_slave_config config;
1756 int ret;
1757
1758 stm32port->tx_buf = dma_alloc_coherent(dev, TX_BUF_L,
1759 &stm32port->tx_dma_buf,
1760 GFP_KERNEL);
1761 if (!stm32port->tx_buf)
1762 return -ENOMEM;
1763
1764 /* Configure DMA channel */
1765 memset(&config, 0, sizeof(config));
1766 config.dst_addr = port->mapbase + ofs->tdr;
1767 config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1768
1769 ret = dmaengine_slave_config(stm32port->tx_ch, &config);
1770 if (ret < 0) {
1771 dev_err(dev, "tx dma channel config failed\n");
1772 stm32_usart_of_dma_tx_remove(stm32port, pdev);
1773 return ret;
1774 }
1775
1776 return 0;
1777}
1778
1779static int stm32_usart_serial_probe(struct platform_device *pdev)
1780{
1781 struct stm32_port *stm32port;
1782 int ret;
1783
1784 stm32port = stm32_usart_of_get_port(pdev);
1785 if (!stm32port)
1786 return -ENODEV;
1787
1788 stm32port->info = of_device_get_match_data(&pdev->dev);
1789 if (!stm32port->info)
1790 return -EINVAL;
1791
1792 stm32port->rx_ch = dma_request_chan(&pdev->dev, "rx");
1793 if (PTR_ERR(stm32port->rx_ch) == -EPROBE_DEFER)
1794 return -EPROBE_DEFER;
1795
1796 /* Fall back in interrupt mode for any non-deferral error */
1797 if (IS_ERR(stm32port->rx_ch))
1798 stm32port->rx_ch = NULL;
1799
1800 stm32port->tx_ch = dma_request_chan(&pdev->dev, "tx");
1801 if (PTR_ERR(stm32port->tx_ch) == -EPROBE_DEFER) {
1802 ret = -EPROBE_DEFER;
1803 goto err_dma_rx;
1804 }
1805 /* Fall back in interrupt mode for any non-deferral error */
1806 if (IS_ERR(stm32port->tx_ch))
1807 stm32port->tx_ch = NULL;
1808
1809 ret = stm32_usart_init_port(stm32port, pdev);
1810 if (ret)
1811 goto err_dma_tx;
1812
1813 if (stm32port->wakeup_src) {
1814 device_set_wakeup_capable(&pdev->dev, true);
1815 ret = dev_pm_set_wake_irq(&pdev->dev, stm32port->port.irq);
1816 if (ret)
1817 goto err_deinit_port;
1818 }
1819
1820 if (stm32port->rx_ch && stm32_usart_of_dma_rx_probe(stm32port, pdev)) {
1821 /* Fall back in interrupt mode */
1822 dma_release_channel(stm32port->rx_ch);
1823 stm32port->rx_ch = NULL;
1824 }
1825
1826 if (stm32port->tx_ch && stm32_usart_of_dma_tx_probe(stm32port, pdev)) {
1827 /* Fall back in interrupt mode */
1828 dma_release_channel(stm32port->tx_ch);
1829 stm32port->tx_ch = NULL;
1830 }
1831
1832 if (!stm32port->rx_ch)
1833 dev_info(&pdev->dev, "interrupt mode for rx (no dma)\n");
1834 if (!stm32port->tx_ch)
1835 dev_info(&pdev->dev, "interrupt mode for tx (no dma)\n");
1836
1837 platform_set_drvdata(pdev, &stm32port->port);
1838
1839 pm_runtime_get_noresume(&pdev->dev);
1840 pm_runtime_set_active(&pdev->dev);
1841 pm_runtime_enable(&pdev->dev);
1842
1843 ret = uart_add_one_port(&stm32_usart_driver, &stm32port->port);
1844 if (ret)
1845 goto err_port;
1846
1847 pm_runtime_put_sync(&pdev->dev);
1848
1849 return 0;
1850
1851err_port:
1852 pm_runtime_disable(&pdev->dev);
1853 pm_runtime_set_suspended(&pdev->dev);
1854 pm_runtime_put_noidle(&pdev->dev);
1855
1856 if (stm32port->tx_ch)
1857 stm32_usart_of_dma_tx_remove(stm32port, pdev);
1858 if (stm32port->rx_ch)
1859 stm32_usart_of_dma_rx_remove(stm32port, pdev);
1860
1861 if (stm32port->wakeup_src)
1862 dev_pm_clear_wake_irq(&pdev->dev);
1863
1864err_deinit_port:
1865 if (stm32port->wakeup_src)
1866 device_set_wakeup_capable(&pdev->dev, false);
1867
1868 stm32_usart_deinit_port(stm32port);
1869
1870err_dma_tx:
1871 if (stm32port->tx_ch)
1872 dma_release_channel(stm32port->tx_ch);
1873
1874err_dma_rx:
1875 if (stm32port->rx_ch)
1876 dma_release_channel(stm32port->rx_ch);
1877
1878 return ret;
1879}
1880
1881static void stm32_usart_serial_remove(struct platform_device *pdev)
1882{
1883 struct uart_port *port = platform_get_drvdata(pdev);
1884 struct stm32_port *stm32_port = to_stm32_port(port);
1885 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1886 u32 cr3;
1887
1888 pm_runtime_get_sync(&pdev->dev);
1889 uart_remove_one_port(&stm32_usart_driver, port);
1890
1891 pm_runtime_disable(&pdev->dev);
1892 pm_runtime_set_suspended(&pdev->dev);
1893 pm_runtime_put_noidle(&pdev->dev);
1894
1895 stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_PEIE);
1896
1897 if (stm32_port->tx_ch) {
1898 stm32_usart_of_dma_tx_remove(stm32_port, pdev);
1899 dma_release_channel(stm32_port->tx_ch);
1900 }
1901
1902 if (stm32_port->rx_ch) {
1903 stm32_usart_of_dma_rx_remove(stm32_port, pdev);
1904 dma_release_channel(stm32_port->rx_ch);
1905 }
1906
1907 cr3 = readl_relaxed(port->membase + ofs->cr3);
1908 cr3 &= ~USART_CR3_EIE;
1909 cr3 &= ~USART_CR3_DMAR;
1910 cr3 &= ~USART_CR3_DMAT;
1911 cr3 &= ~USART_CR3_DDRE;
1912 writel_relaxed(cr3, port->membase + ofs->cr3);
1913
1914 if (stm32_port->wakeup_src) {
1915 dev_pm_clear_wake_irq(&pdev->dev);
1916 device_init_wakeup(&pdev->dev, false);
1917 }
1918
1919 stm32_usart_deinit_port(stm32_port);
1920}
1921
1922static void __maybe_unused stm32_usart_console_putchar(struct uart_port *port, unsigned char ch)
1923{
1924 struct stm32_port *stm32_port = to_stm32_port(port);
1925 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1926 u32 isr;
1927 int ret;
1928
1929 ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr, isr,
1930 (isr & USART_SR_TXE), 100,
1931 STM32_USART_TIMEOUT_USEC);
1932 if (ret != 0) {
1933 dev_err(port->dev, "Error while sending data in UART TX : %d\n", ret);
1934 return;
1935 }
1936 writel_relaxed(ch, port->membase + ofs->tdr);
1937}
1938
1939#ifdef CONFIG_SERIAL_STM32_CONSOLE
1940static void stm32_usart_console_write(struct console *co, const char *s,
1941 unsigned int cnt)
1942{
1943 struct uart_port *port = &stm32_ports[co->index].port;
1944 struct stm32_port *stm32_port = to_stm32_port(port);
1945 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1946 const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
1947 unsigned long flags;
1948 u32 old_cr1, new_cr1;
1949 int locked = 1;
1950
1951 if (oops_in_progress)
1952 locked = uart_port_trylock_irqsave(port, &flags);
1953 else
1954 uart_port_lock_irqsave(port, &flags);
1955
1956 /* Save and disable interrupts, enable the transmitter */
1957 old_cr1 = readl_relaxed(port->membase + ofs->cr1);
1958 new_cr1 = old_cr1 & ~USART_CR1_IE_MASK;
1959 new_cr1 |= USART_CR1_TE | BIT(cfg->uart_enable_bit);
1960 writel_relaxed(new_cr1, port->membase + ofs->cr1);
1961
1962 uart_console_write(port, s, cnt, stm32_usart_console_putchar);
1963
1964 /* Restore interrupt state */
1965 writel_relaxed(old_cr1, port->membase + ofs->cr1);
1966
1967 if (locked)
1968 uart_port_unlock_irqrestore(port, flags);
1969}
1970
1971static int stm32_usart_console_setup(struct console *co, char *options)
1972{
1973 struct stm32_port *stm32port;
1974 int baud = 9600;
1975 int bits = 8;
1976 int parity = 'n';
1977 int flow = 'n';
1978
1979 if (co->index >= STM32_MAX_PORTS)
1980 return -ENODEV;
1981
1982 stm32port = &stm32_ports[co->index];
1983
1984 /*
1985 * This driver does not support early console initialization
1986 * (use ARM early printk support instead), so we only expect
1987 * this to be called during the uart port registration when the
1988 * driver gets probed and the port should be mapped at that point.
1989 */
1990 if (stm32port->port.mapbase == 0 || !stm32port->port.membase)
1991 return -ENXIO;
1992
1993 if (options)
1994 uart_parse_options(options, &baud, &parity, &bits, &flow);
1995
1996 return uart_set_options(&stm32port->port, co, baud, parity, bits, flow);
1997}
1998
1999static struct console stm32_console = {
2000 .name = STM32_SERIAL_NAME,
2001 .device = uart_console_device,
2002 .write = stm32_usart_console_write,
2003 .setup = stm32_usart_console_setup,
2004 .flags = CON_PRINTBUFFER,
2005 .index = -1,
2006 .data = &stm32_usart_driver,
2007};
2008
2009#define STM32_SERIAL_CONSOLE (&stm32_console)
2010
2011#else
2012#define STM32_SERIAL_CONSOLE NULL
2013#endif /* CONFIG_SERIAL_STM32_CONSOLE */
2014
2015#ifdef CONFIG_SERIAL_EARLYCON
2016static void early_stm32_usart_console_putchar(struct uart_port *port, unsigned char ch)
2017{
2018 struct stm32_usart_info *info = port->private_data;
2019
2020 while (!(readl_relaxed(port->membase + info->ofs.isr) & USART_SR_TXE))
2021 cpu_relax();
2022
2023 writel_relaxed(ch, port->membase + info->ofs.tdr);
2024}
2025
2026static void early_stm32_serial_write(struct console *console, const char *s, unsigned int count)
2027{
2028 struct earlycon_device *device = console->data;
2029 struct uart_port *port = &device->port;
2030
2031 uart_console_write(port, s, count, early_stm32_usart_console_putchar);
2032}
2033
2034static int __init early_stm32_h7_serial_setup(struct earlycon_device *device, const char *options)
2035{
2036 if (!(device->port.membase || device->port.iobase))
2037 return -ENODEV;
2038 device->port.private_data = &stm32h7_info;
2039 device->con->write = early_stm32_serial_write;
2040 return 0;
2041}
2042
2043static int __init early_stm32_f7_serial_setup(struct earlycon_device *device, const char *options)
2044{
2045 if (!(device->port.membase || device->port.iobase))
2046 return -ENODEV;
2047 device->port.private_data = &stm32f7_info;
2048 device->con->write = early_stm32_serial_write;
2049 return 0;
2050}
2051
2052static int __init early_stm32_f4_serial_setup(struct earlycon_device *device, const char *options)
2053{
2054 if (!(device->port.membase || device->port.iobase))
2055 return -ENODEV;
2056 device->port.private_data = &stm32f4_info;
2057 device->con->write = early_stm32_serial_write;
2058 return 0;
2059}
2060
2061OF_EARLYCON_DECLARE(stm32, "st,stm32h7-uart", early_stm32_h7_serial_setup);
2062OF_EARLYCON_DECLARE(stm32, "st,stm32f7-uart", early_stm32_f7_serial_setup);
2063OF_EARLYCON_DECLARE(stm32, "st,stm32-uart", early_stm32_f4_serial_setup);
2064#endif /* CONFIG_SERIAL_EARLYCON */
2065
2066static struct uart_driver stm32_usart_driver = {
2067 .driver_name = DRIVER_NAME,
2068 .dev_name = STM32_SERIAL_NAME,
2069 .major = 0,
2070 .minor = 0,
2071 .nr = STM32_MAX_PORTS,
2072 .cons = STM32_SERIAL_CONSOLE,
2073};
2074
2075static int __maybe_unused stm32_usart_serial_en_wakeup(struct uart_port *port,
2076 bool enable)
2077{
2078 struct stm32_port *stm32_port = to_stm32_port(port);
2079 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
2080 struct tty_port *tport = &port->state->port;
2081 int ret;
2082 unsigned int size = 0;
2083 unsigned long flags;
2084
2085 if (!stm32_port->wakeup_src || !tty_port_initialized(tport))
2086 return 0;
2087
2088 /*
2089 * Enable low-power wake-up and wake-up irq if argument is set to
2090 * "enable", disable low-power wake-up and wake-up irq otherwise
2091 */
2092 if (enable) {
2093 stm32_usart_set_bits(port, ofs->cr1, USART_CR1_UESM);
2094 stm32_usart_set_bits(port, ofs->cr3, USART_CR3_WUFIE);
2095 mctrl_gpio_enable_irq_wake(stm32_port->gpios);
2096
2097 /*
2098 * When DMA is used for reception, it must be disabled before
2099 * entering low-power mode and re-enabled when exiting from
2100 * low-power mode.
2101 */
2102 if (stm32_port->rx_ch) {
2103 uart_port_lock_irqsave(port, &flags);
2104 /* Poll data from DMA RX buffer if any */
2105 if (!stm32_usart_rx_dma_pause(stm32_port))
2106 size += stm32_usart_receive_chars(port, true);
2107 stm32_usart_rx_dma_terminate(stm32_port);
2108 uart_unlock_and_check_sysrq_irqrestore(port, flags);
2109 if (size)
2110 tty_flip_buffer_push(tport);
2111 }
2112
2113 /* Poll data from RX FIFO if any */
2114 stm32_usart_receive_chars(port, false);
2115 } else {
2116 if (stm32_port->rx_ch) {
2117 ret = stm32_usart_rx_dma_start_or_resume(port);
2118 if (ret)
2119 return ret;
2120 }
2121 mctrl_gpio_disable_irq_wake(stm32_port->gpios);
2122 stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_UESM);
2123 stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE);
2124 }
2125
2126 return 0;
2127}
2128
2129static int __maybe_unused stm32_usart_serial_suspend(struct device *dev)
2130{
2131 struct uart_port *port = dev_get_drvdata(dev);
2132 int ret;
2133
2134 uart_suspend_port(&stm32_usart_driver, port);
2135
2136 if (device_may_wakeup(dev) || device_wakeup_path(dev)) {
2137 ret = stm32_usart_serial_en_wakeup(port, true);
2138 if (ret)
2139 return ret;
2140 }
2141
2142 /*
2143 * When "no_console_suspend" is enabled, keep the pinctrl default state
2144 * and rely on bootloader stage to restore this state upon resume.
2145 * Otherwise, apply the idle or sleep states depending on wakeup
2146 * capabilities.
2147 */
2148 if (console_suspend_enabled || !uart_console(port)) {
2149 if (device_may_wakeup(dev) || device_wakeup_path(dev))
2150 pinctrl_pm_select_idle_state(dev);
2151 else
2152 pinctrl_pm_select_sleep_state(dev);
2153 }
2154
2155 return 0;
2156}
2157
2158static int __maybe_unused stm32_usart_serial_resume(struct device *dev)
2159{
2160 struct uart_port *port = dev_get_drvdata(dev);
2161 int ret;
2162
2163 pinctrl_pm_select_default_state(dev);
2164
2165 if (device_may_wakeup(dev) || device_wakeup_path(dev)) {
2166 ret = stm32_usart_serial_en_wakeup(port, false);
2167 if (ret)
2168 return ret;
2169 }
2170
2171 return uart_resume_port(&stm32_usart_driver, port);
2172}
2173
2174static int __maybe_unused stm32_usart_runtime_suspend(struct device *dev)
2175{
2176 struct uart_port *port = dev_get_drvdata(dev);
2177 struct stm32_port *stm32port = container_of(port,
2178 struct stm32_port, port);
2179
2180 clk_disable_unprepare(stm32port->clk);
2181
2182 return 0;
2183}
2184
2185static int __maybe_unused stm32_usart_runtime_resume(struct device *dev)
2186{
2187 struct uart_port *port = dev_get_drvdata(dev);
2188 struct stm32_port *stm32port = container_of(port,
2189 struct stm32_port, port);
2190
2191 return clk_prepare_enable(stm32port->clk);
2192}
2193
2194static const struct dev_pm_ops stm32_serial_pm_ops = {
2195 SET_RUNTIME_PM_OPS(stm32_usart_runtime_suspend,
2196 stm32_usart_runtime_resume, NULL)
2197 SET_SYSTEM_SLEEP_PM_OPS(stm32_usart_serial_suspend,
2198 stm32_usart_serial_resume)
2199};
2200
2201static struct platform_driver stm32_serial_driver = {
2202 .probe = stm32_usart_serial_probe,
2203 .remove_new = stm32_usart_serial_remove,
2204 .driver = {
2205 .name = DRIVER_NAME,
2206 .pm = &stm32_serial_pm_ops,
2207 .of_match_table = of_match_ptr(stm32_match),
2208 },
2209};
2210
2211static int __init stm32_usart_init(void)
2212{
2213 static char banner[] __initdata = "STM32 USART driver initialized";
2214 int ret;
2215
2216 pr_info("%s\n", banner);
2217
2218 ret = uart_register_driver(&stm32_usart_driver);
2219 if (ret)
2220 return ret;
2221
2222 ret = platform_driver_register(&stm32_serial_driver);
2223 if (ret)
2224 uart_unregister_driver(&stm32_usart_driver);
2225
2226 return ret;
2227}
2228
2229static void __exit stm32_usart_exit(void)
2230{
2231 platform_driver_unregister(&stm32_serial_driver);
2232 uart_unregister_driver(&stm32_usart_driver);
2233}
2234
2235module_init(stm32_usart_init);
2236module_exit(stm32_usart_exit);
2237
2238MODULE_ALIAS("platform:" DRIVER_NAME);
2239MODULE_DESCRIPTION("STMicroelectronics STM32 serial port driver");
2240MODULE_LICENSE("GPL v2");