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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/platform_device.h>
28#include <linux/pm_runtime.h>
29#include <linux/pm_wakeirq.h>
30#include <linux/serial_core.h>
31#include <linux/serial.h>
32#include <linux/spinlock.h>
33#include <linux/sysrq.h>
34#include <linux/tty_flip.h>
35#include <linux/tty.h>
36
37#include "stm32-usart.h"
38
39static void stm32_stop_tx(struct uart_port *port);
40static void stm32_transmit_chars(struct uart_port *port);
41
42static inline struct stm32_port *to_stm32_port(struct uart_port *port)
43{
44 return container_of(port, struct stm32_port, port);
45}
46
47static void stm32_set_bits(struct uart_port *port, u32 reg, u32 bits)
48{
49 u32 val;
50
51 val = readl_relaxed(port->membase + reg);
52 val |= bits;
53 writel_relaxed(val, port->membase + reg);
54}
55
56static void stm32_clr_bits(struct uart_port *port, u32 reg, u32 bits)
57{
58 u32 val;
59
60 val = readl_relaxed(port->membase + reg);
61 val &= ~bits;
62 writel_relaxed(val, port->membase + reg);
63}
64
65static void stm32_config_reg_rs485(u32 *cr1, u32 *cr3, u32 delay_ADE,
66 u32 delay_DDE, u32 baud)
67{
68 u32 rs485_deat_dedt;
69 u32 rs485_deat_dedt_max = (USART_CR1_DEAT_MASK >> USART_CR1_DEAT_SHIFT);
70 bool over8;
71
72 *cr3 |= USART_CR3_DEM;
73 over8 = *cr1 & USART_CR1_OVER8;
74
75 if (over8)
76 rs485_deat_dedt = delay_ADE * baud * 8;
77 else
78 rs485_deat_dedt = delay_ADE * baud * 16;
79
80 rs485_deat_dedt = DIV_ROUND_CLOSEST(rs485_deat_dedt, 1000);
81 rs485_deat_dedt = rs485_deat_dedt > rs485_deat_dedt_max ?
82 rs485_deat_dedt_max : rs485_deat_dedt;
83 rs485_deat_dedt = (rs485_deat_dedt << USART_CR1_DEAT_SHIFT) &
84 USART_CR1_DEAT_MASK;
85 *cr1 |= rs485_deat_dedt;
86
87 if (over8)
88 rs485_deat_dedt = delay_DDE * baud * 8;
89 else
90 rs485_deat_dedt = delay_DDE * baud * 16;
91
92 rs485_deat_dedt = DIV_ROUND_CLOSEST(rs485_deat_dedt, 1000);
93 rs485_deat_dedt = rs485_deat_dedt > rs485_deat_dedt_max ?
94 rs485_deat_dedt_max : rs485_deat_dedt;
95 rs485_deat_dedt = (rs485_deat_dedt << USART_CR1_DEDT_SHIFT) &
96 USART_CR1_DEDT_MASK;
97 *cr1 |= rs485_deat_dedt;
98}
99
100static int stm32_config_rs485(struct uart_port *port,
101 struct serial_rs485 *rs485conf)
102{
103 struct stm32_port *stm32_port = to_stm32_port(port);
104 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
105 struct stm32_usart_config *cfg = &stm32_port->info->cfg;
106 u32 usartdiv, baud, cr1, cr3;
107 bool over8;
108 unsigned long flags;
109
110 spin_lock_irqsave(&port->lock, flags);
111 stm32_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
112
113 port->rs485 = *rs485conf;
114
115 rs485conf->flags |= SER_RS485_RX_DURING_TX;
116
117 if (rs485conf->flags & SER_RS485_ENABLED) {
118 cr1 = readl_relaxed(port->membase + ofs->cr1);
119 cr3 = readl_relaxed(port->membase + ofs->cr3);
120 usartdiv = readl_relaxed(port->membase + ofs->brr);
121 usartdiv = usartdiv & GENMASK(15, 0);
122 over8 = cr1 & USART_CR1_OVER8;
123
124 if (over8)
125 usartdiv = usartdiv | (usartdiv & GENMASK(4, 0))
126 << USART_BRR_04_R_SHIFT;
127
128 baud = DIV_ROUND_CLOSEST(port->uartclk, usartdiv);
129 stm32_config_reg_rs485(&cr1, &cr3,
130 rs485conf->delay_rts_before_send,
131 rs485conf->delay_rts_after_send, baud);
132
133 if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
134 cr3 &= ~USART_CR3_DEP;
135 rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
136 } else {
137 cr3 |= USART_CR3_DEP;
138 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
139 }
140
141 writel_relaxed(cr3, port->membase + ofs->cr3);
142 writel_relaxed(cr1, port->membase + ofs->cr1);
143 } else {
144 stm32_clr_bits(port, ofs->cr3, USART_CR3_DEM | USART_CR3_DEP);
145 stm32_clr_bits(port, ofs->cr1,
146 USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
147 }
148
149 stm32_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
150 spin_unlock_irqrestore(&port->lock, flags);
151
152 return 0;
153}
154
155static int stm32_init_rs485(struct uart_port *port,
156 struct platform_device *pdev)
157{
158 struct serial_rs485 *rs485conf = &port->rs485;
159
160 rs485conf->flags = 0;
161 rs485conf->delay_rts_before_send = 0;
162 rs485conf->delay_rts_after_send = 0;
163
164 if (!pdev->dev.of_node)
165 return -ENODEV;
166
167 uart_get_rs485_mode(&pdev->dev, rs485conf);
168
169 return 0;
170}
171
172static int stm32_pending_rx(struct uart_port *port, u32 *sr, int *last_res,
173 bool threaded)
174{
175 struct stm32_port *stm32_port = to_stm32_port(port);
176 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
177 enum dma_status status;
178 struct dma_tx_state state;
179
180 *sr = readl_relaxed(port->membase + ofs->isr);
181
182 if (threaded && stm32_port->rx_ch) {
183 status = dmaengine_tx_status(stm32_port->rx_ch,
184 stm32_port->rx_ch->cookie,
185 &state);
186 if ((status == DMA_IN_PROGRESS) &&
187 (*last_res != state.residue))
188 return 1;
189 else
190 return 0;
191 } else if (*sr & USART_SR_RXNE) {
192 return 1;
193 }
194 return 0;
195}
196
197static unsigned long
198stm32_get_char(struct uart_port *port, u32 *sr, int *last_res)
199{
200 struct stm32_port *stm32_port = to_stm32_port(port);
201 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
202 unsigned long c;
203
204 if (stm32_port->rx_ch) {
205 c = stm32_port->rx_buf[RX_BUF_L - (*last_res)--];
206 if ((*last_res) == 0)
207 *last_res = RX_BUF_L;
208 return c;
209 } else {
210 return readl_relaxed(port->membase + ofs->rdr);
211 }
212}
213
214static void stm32_receive_chars(struct uart_port *port, bool threaded)
215{
216 struct tty_port *tport = &port->state->port;
217 struct stm32_port *stm32_port = to_stm32_port(port);
218 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
219 unsigned long c;
220 u32 sr;
221 char flag;
222
223 if (irqd_is_wakeup_set(irq_get_irq_data(port->irq)))
224 pm_wakeup_event(tport->tty->dev, 0);
225
226 while (stm32_pending_rx(port, &sr, &stm32_port->last_res, threaded)) {
227 sr |= USART_SR_DUMMY_RX;
228 c = stm32_get_char(port, &sr, &stm32_port->last_res);
229 flag = TTY_NORMAL;
230 port->icount.rx++;
231
232 if (sr & USART_SR_ERR_MASK) {
233 if (sr & USART_SR_LBD) {
234 port->icount.brk++;
235 if (uart_handle_break(port))
236 continue;
237 } else if (sr & USART_SR_ORE) {
238 if (ofs->icr != UNDEF_REG)
239 writel_relaxed(USART_ICR_ORECF,
240 port->membase +
241 ofs->icr);
242 port->icount.overrun++;
243 } else if (sr & USART_SR_PE) {
244 port->icount.parity++;
245 } else if (sr & USART_SR_FE) {
246 port->icount.frame++;
247 }
248
249 sr &= port->read_status_mask;
250
251 if (sr & USART_SR_LBD)
252 flag = TTY_BREAK;
253 else if (sr & USART_SR_PE)
254 flag = TTY_PARITY;
255 else if (sr & USART_SR_FE)
256 flag = TTY_FRAME;
257 }
258
259 if (uart_handle_sysrq_char(port, c))
260 continue;
261 uart_insert_char(port, sr, USART_SR_ORE, c, flag);
262 }
263
264 spin_unlock(&port->lock);
265 tty_flip_buffer_push(tport);
266 spin_lock(&port->lock);
267}
268
269static void stm32_tx_dma_complete(void *arg)
270{
271 struct uart_port *port = arg;
272 struct stm32_port *stm32port = to_stm32_port(port);
273 struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
274 unsigned int isr;
275 int ret;
276
277 ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr,
278 isr,
279 (isr & USART_SR_TC),
280 10, 100000);
281
282 if (ret)
283 dev_err(port->dev, "terminal count not set\n");
284
285 if (ofs->icr == UNDEF_REG)
286 stm32_clr_bits(port, ofs->isr, USART_SR_TC);
287 else
288 stm32_set_bits(port, ofs->icr, USART_CR_TC);
289
290 stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
291 stm32port->tx_dma_busy = false;
292
293 /* Let's see if we have pending data to send */
294 stm32_transmit_chars(port);
295}
296
297static void stm32_transmit_chars_pio(struct uart_port *port)
298{
299 struct stm32_port *stm32_port = to_stm32_port(port);
300 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
301 struct circ_buf *xmit = &port->state->xmit;
302 unsigned int isr;
303 int ret;
304
305 if (stm32_port->tx_dma_busy) {
306 stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
307 stm32_port->tx_dma_busy = false;
308 }
309
310 ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr,
311 isr,
312 (isr & USART_SR_TXE),
313 10, 100000);
314
315 if (ret)
316 dev_err(port->dev, "tx empty not set\n");
317
318 stm32_set_bits(port, ofs->cr1, USART_CR1_TXEIE);
319
320 writel_relaxed(xmit->buf[xmit->tail], port->membase + ofs->tdr);
321 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
322 port->icount.tx++;
323}
324
325static void stm32_transmit_chars_dma(struct uart_port *port)
326{
327 struct stm32_port *stm32port = to_stm32_port(port);
328 struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
329 struct circ_buf *xmit = &port->state->xmit;
330 struct dma_async_tx_descriptor *desc = NULL;
331 dma_cookie_t cookie;
332 unsigned int count, i;
333
334 if (stm32port->tx_dma_busy)
335 return;
336
337 stm32port->tx_dma_busy = true;
338
339 count = uart_circ_chars_pending(xmit);
340
341 if (count > TX_BUF_L)
342 count = TX_BUF_L;
343
344 if (xmit->tail < xmit->head) {
345 memcpy(&stm32port->tx_buf[0], &xmit->buf[xmit->tail], count);
346 } else {
347 size_t one = UART_XMIT_SIZE - xmit->tail;
348 size_t two;
349
350 if (one > count)
351 one = count;
352 two = count - one;
353
354 memcpy(&stm32port->tx_buf[0], &xmit->buf[xmit->tail], one);
355 if (two)
356 memcpy(&stm32port->tx_buf[one], &xmit->buf[0], two);
357 }
358
359 desc = dmaengine_prep_slave_single(stm32port->tx_ch,
360 stm32port->tx_dma_buf,
361 count,
362 DMA_MEM_TO_DEV,
363 DMA_PREP_INTERRUPT);
364
365 if (!desc) {
366 for (i = count; i > 0; i--)
367 stm32_transmit_chars_pio(port);
368 return;
369 }
370
371 desc->callback = stm32_tx_dma_complete;
372 desc->callback_param = port;
373
374 /* Push current DMA TX transaction in the pending queue */
375 cookie = dmaengine_submit(desc);
376
377 /* Issue pending DMA TX requests */
378 dma_async_issue_pending(stm32port->tx_ch);
379
380 stm32_clr_bits(port, ofs->isr, USART_SR_TC);
381 stm32_set_bits(port, ofs->cr3, USART_CR3_DMAT);
382
383 xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
384 port->icount.tx += count;
385}
386
387static void stm32_transmit_chars(struct uart_port *port)
388{
389 struct stm32_port *stm32_port = to_stm32_port(port);
390 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
391 struct circ_buf *xmit = &port->state->xmit;
392
393 if (port->x_char) {
394 if (stm32_port->tx_dma_busy)
395 stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
396 writel_relaxed(port->x_char, port->membase + ofs->tdr);
397 port->x_char = 0;
398 port->icount.tx++;
399 if (stm32_port->tx_dma_busy)
400 stm32_set_bits(port, ofs->cr3, USART_CR3_DMAT);
401 return;
402 }
403
404 if (uart_tx_stopped(port)) {
405 stm32_stop_tx(port);
406 return;
407 }
408
409 if (uart_circ_empty(xmit)) {
410 stm32_stop_tx(port);
411 return;
412 }
413
414 if (stm32_port->tx_ch)
415 stm32_transmit_chars_dma(port);
416 else
417 stm32_transmit_chars_pio(port);
418
419 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
420 uart_write_wakeup(port);
421
422 if (uart_circ_empty(xmit))
423 stm32_stop_tx(port);
424}
425
426static irqreturn_t stm32_interrupt(int irq, void *ptr)
427{
428 struct uart_port *port = ptr;
429 struct stm32_port *stm32_port = to_stm32_port(port);
430 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
431 u32 sr;
432
433 spin_lock(&port->lock);
434
435 sr = readl_relaxed(port->membase + ofs->isr);
436
437 if ((sr & USART_SR_WUF) && (ofs->icr != UNDEF_REG))
438 writel_relaxed(USART_ICR_WUCF,
439 port->membase + ofs->icr);
440
441 if ((sr & USART_SR_RXNE) && !(stm32_port->rx_ch))
442 stm32_receive_chars(port, false);
443
444 if ((sr & USART_SR_TXE) && !(stm32_port->tx_ch))
445 stm32_transmit_chars(port);
446
447 spin_unlock(&port->lock);
448
449 if (stm32_port->rx_ch)
450 return IRQ_WAKE_THREAD;
451 else
452 return IRQ_HANDLED;
453}
454
455static irqreturn_t stm32_threaded_interrupt(int irq, void *ptr)
456{
457 struct uart_port *port = ptr;
458 struct stm32_port *stm32_port = to_stm32_port(port);
459
460 spin_lock(&port->lock);
461
462 if (stm32_port->rx_ch)
463 stm32_receive_chars(port, true);
464
465 spin_unlock(&port->lock);
466
467 return IRQ_HANDLED;
468}
469
470static unsigned int stm32_tx_empty(struct uart_port *port)
471{
472 struct stm32_port *stm32_port = to_stm32_port(port);
473 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
474
475 return readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE;
476}
477
478static void stm32_set_mctrl(struct uart_port *port, unsigned int mctrl)
479{
480 struct stm32_port *stm32_port = to_stm32_port(port);
481 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
482
483 if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS))
484 stm32_set_bits(port, ofs->cr3, USART_CR3_RTSE);
485 else
486 stm32_clr_bits(port, ofs->cr3, USART_CR3_RTSE);
487}
488
489static unsigned int stm32_get_mctrl(struct uart_port *port)
490{
491 /* This routine is used to get signals of: DCD, DSR, RI, and CTS */
492 return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
493}
494
495/* Transmit stop */
496static void stm32_stop_tx(struct uart_port *port)
497{
498 struct stm32_port *stm32_port = to_stm32_port(port);
499 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
500
501 stm32_clr_bits(port, ofs->cr1, USART_CR1_TXEIE);
502}
503
504/* There are probably characters waiting to be transmitted. */
505static void stm32_start_tx(struct uart_port *port)
506{
507 struct circ_buf *xmit = &port->state->xmit;
508
509 if (uart_circ_empty(xmit))
510 return;
511
512 stm32_transmit_chars(port);
513}
514
515/* Throttle the remote when input buffer is about to overflow. */
516static void stm32_throttle(struct uart_port *port)
517{
518 struct stm32_port *stm32_port = to_stm32_port(port);
519 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
520 unsigned long flags;
521
522 spin_lock_irqsave(&port->lock, flags);
523 stm32_clr_bits(port, ofs->cr1, USART_CR1_RXNEIE);
524 spin_unlock_irqrestore(&port->lock, flags);
525}
526
527/* Unthrottle the remote, the input buffer can now accept data. */
528static void stm32_unthrottle(struct uart_port *port)
529{
530 struct stm32_port *stm32_port = to_stm32_port(port);
531 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
532 unsigned long flags;
533
534 spin_lock_irqsave(&port->lock, flags);
535 stm32_set_bits(port, ofs->cr1, USART_CR1_RXNEIE);
536 spin_unlock_irqrestore(&port->lock, flags);
537}
538
539/* Receive stop */
540static void stm32_stop_rx(struct uart_port *port)
541{
542 struct stm32_port *stm32_port = to_stm32_port(port);
543 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
544
545 stm32_clr_bits(port, ofs->cr1, USART_CR1_RXNEIE);
546}
547
548/* Handle breaks - ignored by us */
549static void stm32_break_ctl(struct uart_port *port, int break_state)
550{
551}
552
553static int stm32_startup(struct uart_port *port)
554{
555 struct stm32_port *stm32_port = to_stm32_port(port);
556 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
557 struct stm32_usart_config *cfg = &stm32_port->info->cfg;
558 const char *name = to_platform_device(port->dev)->name;
559 u32 val;
560 int ret;
561
562 ret = request_threaded_irq(port->irq, stm32_interrupt,
563 stm32_threaded_interrupt,
564 IRQF_NO_SUSPEND, name, port);
565 if (ret)
566 return ret;
567
568 if (cfg->has_wakeup && stm32_port->wakeirq >= 0) {
569 ret = dev_pm_set_dedicated_wake_irq(port->dev,
570 stm32_port->wakeirq);
571 if (ret) {
572 free_irq(port->irq, port);
573 return ret;
574 }
575 }
576
577 val = USART_CR1_RXNEIE | USART_CR1_TE | USART_CR1_RE;
578 if (stm32_port->fifoen)
579 val |= USART_CR1_FIFOEN;
580 stm32_set_bits(port, ofs->cr1, val);
581
582 return 0;
583}
584
585static void stm32_shutdown(struct uart_port *port)
586{
587 struct stm32_port *stm32_port = to_stm32_port(port);
588 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
589 struct stm32_usart_config *cfg = &stm32_port->info->cfg;
590 u32 val;
591
592 val = USART_CR1_TXEIE | USART_CR1_RXNEIE | USART_CR1_TE | USART_CR1_RE;
593 val |= BIT(cfg->uart_enable_bit);
594 if (stm32_port->fifoen)
595 val |= USART_CR1_FIFOEN;
596 stm32_clr_bits(port, ofs->cr1, val);
597
598 dev_pm_clear_wake_irq(port->dev);
599 free_irq(port->irq, port);
600}
601
602static void stm32_set_termios(struct uart_port *port, struct ktermios *termios,
603 struct ktermios *old)
604{
605 struct stm32_port *stm32_port = to_stm32_port(port);
606 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
607 struct stm32_usart_config *cfg = &stm32_port->info->cfg;
608 struct serial_rs485 *rs485conf = &port->rs485;
609 unsigned int baud;
610 u32 usartdiv, mantissa, fraction, oversampling;
611 tcflag_t cflag = termios->c_cflag;
612 u32 cr1, cr2, cr3;
613 unsigned long flags;
614
615 if (!stm32_port->hw_flow_control)
616 cflag &= ~CRTSCTS;
617
618 baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 8);
619
620 spin_lock_irqsave(&port->lock, flags);
621
622 /* Stop serial port and reset value */
623 writel_relaxed(0, port->membase + ofs->cr1);
624
625 cr1 = USART_CR1_TE | USART_CR1_RE | USART_CR1_RXNEIE;
626
627 if (stm32_port->fifoen)
628 cr1 |= USART_CR1_FIFOEN;
629 cr2 = 0;
630 cr3 = 0;
631
632 if (cflag & CSTOPB)
633 cr2 |= USART_CR2_STOP_2B;
634
635 if (cflag & PARENB) {
636 cr1 |= USART_CR1_PCE;
637 if ((cflag & CSIZE) == CS8) {
638 if (cfg->has_7bits_data)
639 cr1 |= USART_CR1_M0;
640 else
641 cr1 |= USART_CR1_M;
642 }
643 }
644
645 if (cflag & PARODD)
646 cr1 |= USART_CR1_PS;
647
648 port->status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS);
649 if (cflag & CRTSCTS) {
650 port->status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
651 cr3 |= USART_CR3_CTSE | USART_CR3_RTSE;
652 }
653
654 usartdiv = DIV_ROUND_CLOSEST(port->uartclk, baud);
655
656 /*
657 * The USART supports 16 or 8 times oversampling.
658 * By default we prefer 16 times oversampling, so that the receiver
659 * has a better tolerance to clock deviations.
660 * 8 times oversampling is only used to achieve higher speeds.
661 */
662 if (usartdiv < 16) {
663 oversampling = 8;
664 cr1 |= USART_CR1_OVER8;
665 stm32_set_bits(port, ofs->cr1, USART_CR1_OVER8);
666 } else {
667 oversampling = 16;
668 cr1 &= ~USART_CR1_OVER8;
669 stm32_clr_bits(port, ofs->cr1, USART_CR1_OVER8);
670 }
671
672 mantissa = (usartdiv / oversampling) << USART_BRR_DIV_M_SHIFT;
673 fraction = usartdiv % oversampling;
674 writel_relaxed(mantissa | fraction, port->membase + ofs->brr);
675
676 uart_update_timeout(port, cflag, baud);
677
678 port->read_status_mask = USART_SR_ORE;
679 if (termios->c_iflag & INPCK)
680 port->read_status_mask |= USART_SR_PE | USART_SR_FE;
681 if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
682 port->read_status_mask |= USART_SR_LBD;
683
684 /* Characters to ignore */
685 port->ignore_status_mask = 0;
686 if (termios->c_iflag & IGNPAR)
687 port->ignore_status_mask = USART_SR_PE | USART_SR_FE;
688 if (termios->c_iflag & IGNBRK) {
689 port->ignore_status_mask |= USART_SR_LBD;
690 /*
691 * If we're ignoring parity and break indicators,
692 * ignore overruns too (for real raw support).
693 */
694 if (termios->c_iflag & IGNPAR)
695 port->ignore_status_mask |= USART_SR_ORE;
696 }
697
698 /* Ignore all characters if CREAD is not set */
699 if ((termios->c_cflag & CREAD) == 0)
700 port->ignore_status_mask |= USART_SR_DUMMY_RX;
701
702 if (stm32_port->rx_ch)
703 cr3 |= USART_CR3_DMAR;
704
705 if (rs485conf->flags & SER_RS485_ENABLED) {
706 stm32_config_reg_rs485(&cr1, &cr3,
707 rs485conf->delay_rts_before_send,
708 rs485conf->delay_rts_after_send, baud);
709 if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
710 cr3 &= ~USART_CR3_DEP;
711 rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
712 } else {
713 cr3 |= USART_CR3_DEP;
714 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
715 }
716
717 } else {
718 cr3 &= ~(USART_CR3_DEM | USART_CR3_DEP);
719 cr1 &= ~(USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
720 }
721
722 writel_relaxed(cr3, port->membase + ofs->cr3);
723 writel_relaxed(cr2, port->membase + ofs->cr2);
724 writel_relaxed(cr1, port->membase + ofs->cr1);
725
726 stm32_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
727 spin_unlock_irqrestore(&port->lock, flags);
728}
729
730static const char *stm32_type(struct uart_port *port)
731{
732 return (port->type == PORT_STM32) ? DRIVER_NAME : NULL;
733}
734
735static void stm32_release_port(struct uart_port *port)
736{
737}
738
739static int stm32_request_port(struct uart_port *port)
740{
741 return 0;
742}
743
744static void stm32_config_port(struct uart_port *port, int flags)
745{
746 if (flags & UART_CONFIG_TYPE)
747 port->type = PORT_STM32;
748}
749
750static int
751stm32_verify_port(struct uart_port *port, struct serial_struct *ser)
752{
753 /* No user changeable parameters */
754 return -EINVAL;
755}
756
757static void stm32_pm(struct uart_port *port, unsigned int state,
758 unsigned int oldstate)
759{
760 struct stm32_port *stm32port = container_of(port,
761 struct stm32_port, port);
762 struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
763 struct stm32_usart_config *cfg = &stm32port->info->cfg;
764 unsigned long flags = 0;
765
766 switch (state) {
767 case UART_PM_STATE_ON:
768 clk_prepare_enable(stm32port->clk);
769 break;
770 case UART_PM_STATE_OFF:
771 spin_lock_irqsave(&port->lock, flags);
772 stm32_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
773 spin_unlock_irqrestore(&port->lock, flags);
774 clk_disable_unprepare(stm32port->clk);
775 break;
776 }
777}
778
779static const struct uart_ops stm32_uart_ops = {
780 .tx_empty = stm32_tx_empty,
781 .set_mctrl = stm32_set_mctrl,
782 .get_mctrl = stm32_get_mctrl,
783 .stop_tx = stm32_stop_tx,
784 .start_tx = stm32_start_tx,
785 .throttle = stm32_throttle,
786 .unthrottle = stm32_unthrottle,
787 .stop_rx = stm32_stop_rx,
788 .break_ctl = stm32_break_ctl,
789 .startup = stm32_startup,
790 .shutdown = stm32_shutdown,
791 .set_termios = stm32_set_termios,
792 .pm = stm32_pm,
793 .type = stm32_type,
794 .release_port = stm32_release_port,
795 .request_port = stm32_request_port,
796 .config_port = stm32_config_port,
797 .verify_port = stm32_verify_port,
798};
799
800static int stm32_init_port(struct stm32_port *stm32port,
801 struct platform_device *pdev)
802{
803 struct uart_port *port = &stm32port->port;
804 struct resource *res;
805 int ret;
806
807 port->iotype = UPIO_MEM;
808 port->flags = UPF_BOOT_AUTOCONF;
809 port->ops = &stm32_uart_ops;
810 port->dev = &pdev->dev;
811 port->irq = platform_get_irq(pdev, 0);
812 port->rs485_config = stm32_config_rs485;
813
814 stm32_init_rs485(port, pdev);
815
816 stm32port->wakeirq = platform_get_irq(pdev, 1);
817 stm32port->fifoen = stm32port->info->cfg.has_fifo;
818
819 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
820 port->membase = devm_ioremap_resource(&pdev->dev, res);
821 if (IS_ERR(port->membase))
822 return PTR_ERR(port->membase);
823 port->mapbase = res->start;
824
825 spin_lock_init(&port->lock);
826
827 stm32port->clk = devm_clk_get(&pdev->dev, NULL);
828 if (IS_ERR(stm32port->clk))
829 return PTR_ERR(stm32port->clk);
830
831 /* Ensure that clk rate is correct by enabling the clk */
832 ret = clk_prepare_enable(stm32port->clk);
833 if (ret)
834 return ret;
835
836 stm32port->port.uartclk = clk_get_rate(stm32port->clk);
837 if (!stm32port->port.uartclk) {
838 clk_disable_unprepare(stm32port->clk);
839 ret = -EINVAL;
840 }
841
842 return ret;
843}
844
845static struct stm32_port *stm32_of_get_stm32_port(struct platform_device *pdev)
846{
847 struct device_node *np = pdev->dev.of_node;
848 int id;
849
850 if (!np)
851 return NULL;
852
853 id = of_alias_get_id(np, "serial");
854 if (id < 0) {
855 dev_err(&pdev->dev, "failed to get alias id, errno %d\n", id);
856 return NULL;
857 }
858
859 if (WARN_ON(id >= STM32_MAX_PORTS))
860 return NULL;
861
862 stm32_ports[id].hw_flow_control = of_property_read_bool(np,
863 "st,hw-flow-ctrl");
864 stm32_ports[id].port.line = id;
865 stm32_ports[id].last_res = RX_BUF_L;
866 return &stm32_ports[id];
867}
868
869#ifdef CONFIG_OF
870static const struct of_device_id stm32_match[] = {
871 { .compatible = "st,stm32-uart", .data = &stm32f4_info},
872 { .compatible = "st,stm32f7-uart", .data = &stm32f7_info},
873 { .compatible = "st,stm32h7-uart", .data = &stm32h7_info},
874 {},
875};
876
877MODULE_DEVICE_TABLE(of, stm32_match);
878#endif
879
880static int stm32_of_dma_rx_probe(struct stm32_port *stm32port,
881 struct platform_device *pdev)
882{
883 struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
884 struct uart_port *port = &stm32port->port;
885 struct device *dev = &pdev->dev;
886 struct dma_slave_config config;
887 struct dma_async_tx_descriptor *desc = NULL;
888 dma_cookie_t cookie;
889 int ret;
890
891 /* Request DMA RX channel */
892 stm32port->rx_ch = dma_request_slave_channel(dev, "rx");
893 if (!stm32port->rx_ch) {
894 dev_info(dev, "rx dma alloc failed\n");
895 return -ENODEV;
896 }
897 stm32port->rx_buf = dma_alloc_coherent(&pdev->dev, RX_BUF_L,
898 &stm32port->rx_dma_buf,
899 GFP_KERNEL);
900 if (!stm32port->rx_buf) {
901 ret = -ENOMEM;
902 goto alloc_err;
903 }
904
905 /* Configure DMA channel */
906 memset(&config, 0, sizeof(config));
907 config.src_addr = port->mapbase + ofs->rdr;
908 config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
909
910 ret = dmaengine_slave_config(stm32port->rx_ch, &config);
911 if (ret < 0) {
912 dev_err(dev, "rx dma channel config failed\n");
913 ret = -ENODEV;
914 goto config_err;
915 }
916
917 /* Prepare a DMA cyclic transaction */
918 desc = dmaengine_prep_dma_cyclic(stm32port->rx_ch,
919 stm32port->rx_dma_buf,
920 RX_BUF_L, RX_BUF_P, DMA_DEV_TO_MEM,
921 DMA_PREP_INTERRUPT);
922 if (!desc) {
923 dev_err(dev, "rx dma prep cyclic failed\n");
924 ret = -ENODEV;
925 goto config_err;
926 }
927
928 /* No callback as dma buffer is drained on usart interrupt */
929 desc->callback = NULL;
930 desc->callback_param = NULL;
931
932 /* Push current DMA transaction in the pending queue */
933 cookie = dmaengine_submit(desc);
934
935 /* Issue pending DMA requests */
936 dma_async_issue_pending(stm32port->rx_ch);
937
938 return 0;
939
940config_err:
941 dma_free_coherent(&pdev->dev,
942 RX_BUF_L, stm32port->rx_buf,
943 stm32port->rx_dma_buf);
944
945alloc_err:
946 dma_release_channel(stm32port->rx_ch);
947 stm32port->rx_ch = NULL;
948
949 return ret;
950}
951
952static int stm32_of_dma_tx_probe(struct stm32_port *stm32port,
953 struct platform_device *pdev)
954{
955 struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
956 struct uart_port *port = &stm32port->port;
957 struct device *dev = &pdev->dev;
958 struct dma_slave_config config;
959 int ret;
960
961 stm32port->tx_dma_busy = false;
962
963 /* Request DMA TX channel */
964 stm32port->tx_ch = dma_request_slave_channel(dev, "tx");
965 if (!stm32port->tx_ch) {
966 dev_info(dev, "tx dma alloc failed\n");
967 return -ENODEV;
968 }
969 stm32port->tx_buf = dma_alloc_coherent(&pdev->dev, TX_BUF_L,
970 &stm32port->tx_dma_buf,
971 GFP_KERNEL);
972 if (!stm32port->tx_buf) {
973 ret = -ENOMEM;
974 goto alloc_err;
975 }
976
977 /* Configure DMA channel */
978 memset(&config, 0, sizeof(config));
979 config.dst_addr = port->mapbase + ofs->tdr;
980 config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
981
982 ret = dmaengine_slave_config(stm32port->tx_ch, &config);
983 if (ret < 0) {
984 dev_err(dev, "tx dma channel config failed\n");
985 ret = -ENODEV;
986 goto config_err;
987 }
988
989 return 0;
990
991config_err:
992 dma_free_coherent(&pdev->dev,
993 TX_BUF_L, stm32port->tx_buf,
994 stm32port->tx_dma_buf);
995
996alloc_err:
997 dma_release_channel(stm32port->tx_ch);
998 stm32port->tx_ch = NULL;
999
1000 return ret;
1001}
1002
1003static int stm32_serial_probe(struct platform_device *pdev)
1004{
1005 const struct of_device_id *match;
1006 struct stm32_port *stm32port;
1007 int ret;
1008
1009 stm32port = stm32_of_get_stm32_port(pdev);
1010 if (!stm32port)
1011 return -ENODEV;
1012
1013 match = of_match_device(stm32_match, &pdev->dev);
1014 if (match && match->data)
1015 stm32port->info = (struct stm32_usart_info *)match->data;
1016 else
1017 return -EINVAL;
1018
1019 ret = stm32_init_port(stm32port, pdev);
1020 if (ret)
1021 return ret;
1022
1023 if (stm32port->info->cfg.has_wakeup && stm32port->wakeirq >= 0) {
1024 ret = device_init_wakeup(&pdev->dev, true);
1025 if (ret)
1026 goto err_uninit;
1027 }
1028
1029 ret = uart_add_one_port(&stm32_usart_driver, &stm32port->port);
1030 if (ret)
1031 goto err_nowup;
1032
1033 ret = stm32_of_dma_rx_probe(stm32port, pdev);
1034 if (ret)
1035 dev_info(&pdev->dev, "interrupt mode used for rx (no dma)\n");
1036
1037 ret = stm32_of_dma_tx_probe(stm32port, pdev);
1038 if (ret)
1039 dev_info(&pdev->dev, "interrupt mode used for tx (no dma)\n");
1040
1041 platform_set_drvdata(pdev, &stm32port->port);
1042
1043 return 0;
1044
1045err_nowup:
1046 if (stm32port->info->cfg.has_wakeup && stm32port->wakeirq >= 0)
1047 device_init_wakeup(&pdev->dev, false);
1048
1049err_uninit:
1050 clk_disable_unprepare(stm32port->clk);
1051
1052 return ret;
1053}
1054
1055static int stm32_serial_remove(struct platform_device *pdev)
1056{
1057 struct uart_port *port = platform_get_drvdata(pdev);
1058 struct stm32_port *stm32_port = to_stm32_port(port);
1059 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1060 struct stm32_usart_config *cfg = &stm32_port->info->cfg;
1061
1062 stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAR);
1063
1064 if (stm32_port->rx_ch)
1065 dma_release_channel(stm32_port->rx_ch);
1066
1067 if (stm32_port->rx_dma_buf)
1068 dma_free_coherent(&pdev->dev,
1069 RX_BUF_L, stm32_port->rx_buf,
1070 stm32_port->rx_dma_buf);
1071
1072 stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
1073
1074 if (stm32_port->tx_ch)
1075 dma_release_channel(stm32_port->tx_ch);
1076
1077 if (stm32_port->tx_dma_buf)
1078 dma_free_coherent(&pdev->dev,
1079 TX_BUF_L, stm32_port->tx_buf,
1080 stm32_port->tx_dma_buf);
1081
1082 if (cfg->has_wakeup && stm32_port->wakeirq >= 0)
1083 device_init_wakeup(&pdev->dev, false);
1084
1085 clk_disable_unprepare(stm32_port->clk);
1086
1087 return uart_remove_one_port(&stm32_usart_driver, port);
1088}
1089
1090
1091#ifdef CONFIG_SERIAL_STM32_CONSOLE
1092static void stm32_console_putchar(struct uart_port *port, int ch)
1093{
1094 struct stm32_port *stm32_port = to_stm32_port(port);
1095 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1096
1097 while (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE))
1098 cpu_relax();
1099
1100 writel_relaxed(ch, port->membase + ofs->tdr);
1101}
1102
1103static void stm32_console_write(struct console *co, const char *s, unsigned cnt)
1104{
1105 struct uart_port *port = &stm32_ports[co->index].port;
1106 struct stm32_port *stm32_port = to_stm32_port(port);
1107 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1108 struct stm32_usart_config *cfg = &stm32_port->info->cfg;
1109 unsigned long flags;
1110 u32 old_cr1, new_cr1;
1111 int locked = 1;
1112
1113 local_irq_save(flags);
1114 if (port->sysrq)
1115 locked = 0;
1116 else if (oops_in_progress)
1117 locked = spin_trylock(&port->lock);
1118 else
1119 spin_lock(&port->lock);
1120
1121 /* Save and disable interrupts, enable the transmitter */
1122 old_cr1 = readl_relaxed(port->membase + ofs->cr1);
1123 new_cr1 = old_cr1 & ~USART_CR1_IE_MASK;
1124 new_cr1 |= USART_CR1_TE | BIT(cfg->uart_enable_bit);
1125 writel_relaxed(new_cr1, port->membase + ofs->cr1);
1126
1127 uart_console_write(port, s, cnt, stm32_console_putchar);
1128
1129 /* Restore interrupt state */
1130 writel_relaxed(old_cr1, port->membase + ofs->cr1);
1131
1132 if (locked)
1133 spin_unlock(&port->lock);
1134 local_irq_restore(flags);
1135}
1136
1137static int stm32_console_setup(struct console *co, char *options)
1138{
1139 struct stm32_port *stm32port;
1140 int baud = 9600;
1141 int bits = 8;
1142 int parity = 'n';
1143 int flow = 'n';
1144
1145 if (co->index >= STM32_MAX_PORTS)
1146 return -ENODEV;
1147
1148 stm32port = &stm32_ports[co->index];
1149
1150 /*
1151 * This driver does not support early console initialization
1152 * (use ARM early printk support instead), so we only expect
1153 * this to be called during the uart port registration when the
1154 * driver gets probed and the port should be mapped at that point.
1155 */
1156 if (stm32port->port.mapbase == 0 || stm32port->port.membase == NULL)
1157 return -ENXIO;
1158
1159 if (options)
1160 uart_parse_options(options, &baud, &parity, &bits, &flow);
1161
1162 return uart_set_options(&stm32port->port, co, baud, parity, bits, flow);
1163}
1164
1165static struct console stm32_console = {
1166 .name = STM32_SERIAL_NAME,
1167 .device = uart_console_device,
1168 .write = stm32_console_write,
1169 .setup = stm32_console_setup,
1170 .flags = CON_PRINTBUFFER,
1171 .index = -1,
1172 .data = &stm32_usart_driver,
1173};
1174
1175#define STM32_SERIAL_CONSOLE (&stm32_console)
1176
1177#else
1178#define STM32_SERIAL_CONSOLE NULL
1179#endif /* CONFIG_SERIAL_STM32_CONSOLE */
1180
1181static struct uart_driver stm32_usart_driver = {
1182 .driver_name = DRIVER_NAME,
1183 .dev_name = STM32_SERIAL_NAME,
1184 .major = 0,
1185 .minor = 0,
1186 .nr = STM32_MAX_PORTS,
1187 .cons = STM32_SERIAL_CONSOLE,
1188};
1189
1190#ifdef CONFIG_PM_SLEEP
1191static void stm32_serial_enable_wakeup(struct uart_port *port, bool enable)
1192{
1193 struct stm32_port *stm32_port = to_stm32_port(port);
1194 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1195 struct stm32_usart_config *cfg = &stm32_port->info->cfg;
1196 u32 val;
1197
1198 if (!cfg->has_wakeup || stm32_port->wakeirq < 0)
1199 return;
1200
1201 if (enable) {
1202 stm32_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
1203 stm32_set_bits(port, ofs->cr1, USART_CR1_UESM);
1204 val = readl_relaxed(port->membase + ofs->cr3);
1205 val &= ~USART_CR3_WUS_MASK;
1206 /* Enable Wake up interrupt from low power on start bit */
1207 val |= USART_CR3_WUS_START_BIT | USART_CR3_WUFIE;
1208 writel_relaxed(val, port->membase + ofs->cr3);
1209 stm32_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
1210 } else {
1211 stm32_clr_bits(port, ofs->cr1, USART_CR1_UESM);
1212 }
1213}
1214
1215static int stm32_serial_suspend(struct device *dev)
1216{
1217 struct uart_port *port = dev_get_drvdata(dev);
1218
1219 uart_suspend_port(&stm32_usart_driver, port);
1220
1221 if (device_may_wakeup(dev))
1222 stm32_serial_enable_wakeup(port, true);
1223 else
1224 stm32_serial_enable_wakeup(port, false);
1225
1226 return 0;
1227}
1228
1229static int stm32_serial_resume(struct device *dev)
1230{
1231 struct uart_port *port = dev_get_drvdata(dev);
1232
1233 if (device_may_wakeup(dev))
1234 stm32_serial_enable_wakeup(port, false);
1235
1236 return uart_resume_port(&stm32_usart_driver, port);
1237}
1238#endif /* CONFIG_PM_SLEEP */
1239
1240static const struct dev_pm_ops stm32_serial_pm_ops = {
1241 SET_SYSTEM_SLEEP_PM_OPS(stm32_serial_suspend, stm32_serial_resume)
1242};
1243
1244static struct platform_driver stm32_serial_driver = {
1245 .probe = stm32_serial_probe,
1246 .remove = stm32_serial_remove,
1247 .driver = {
1248 .name = DRIVER_NAME,
1249 .pm = &stm32_serial_pm_ops,
1250 .of_match_table = of_match_ptr(stm32_match),
1251 },
1252};
1253
1254static int __init usart_init(void)
1255{
1256 static char banner[] __initdata = "STM32 USART driver initialized";
1257 int ret;
1258
1259 pr_info("%s\n", banner);
1260
1261 ret = uart_register_driver(&stm32_usart_driver);
1262 if (ret)
1263 return ret;
1264
1265 ret = platform_driver_register(&stm32_serial_driver);
1266 if (ret)
1267 uart_unregister_driver(&stm32_usart_driver);
1268
1269 return ret;
1270}
1271
1272static void __exit usart_exit(void)
1273{
1274 platform_driver_unregister(&stm32_serial_driver);
1275 uart_unregister_driver(&stm32_usart_driver);
1276}
1277
1278module_init(usart_init);
1279module_exit(usart_exit);
1280
1281MODULE_ALIAS("platform:" DRIVER_NAME);
1282MODULE_DESCRIPTION("STMicroelectronics STM32 serial port driver");
1283MODULE_LICENSE("GPL v2");