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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * serial_tegra.c
4 *
5 * High-speed serial driver for NVIDIA Tegra SoCs
6 *
7 * Copyright (c) 2012-2019, NVIDIA CORPORATION. All rights reserved.
8 *
9 * Author: Laxman Dewangan <ldewangan@nvidia.com>
10 */
11
12#include <linux/clk.h>
13#include <linux/debugfs.h>
14#include <linux/delay.h>
15#include <linux/dmaengine.h>
16#include <linux/dma-mapping.h>
17#include <linux/dmapool.h>
18#include <linux/err.h>
19#include <linux/io.h>
20#include <linux/irq.h>
21#include <linux/module.h>
22#include <linux/of.h>
23#include <linux/of_device.h>
24#include <linux/pagemap.h>
25#include <linux/platform_device.h>
26#include <linux/reset.h>
27#include <linux/serial.h>
28#include <linux/serial_8250.h>
29#include <linux/serial_core.h>
30#include <linux/serial_reg.h>
31#include <linux/slab.h>
32#include <linux/string.h>
33#include <linux/termios.h>
34#include <linux/tty.h>
35#include <linux/tty_flip.h>
36
37#define TEGRA_UART_TYPE "TEGRA_UART"
38#define TX_EMPTY_STATUS (UART_LSR_TEMT | UART_LSR_THRE)
39#define BYTES_TO_ALIGN(x) ((unsigned long)(x) & 0x3)
40
41#define TEGRA_UART_RX_DMA_BUFFER_SIZE 4096
42#define TEGRA_UART_LSR_TXFIFO_FULL 0x100
43#define TEGRA_UART_IER_EORD 0x20
44#define TEGRA_UART_MCR_RTS_EN 0x40
45#define TEGRA_UART_MCR_CTS_EN 0x20
46#define TEGRA_UART_LSR_ANY (UART_LSR_OE | UART_LSR_BI | \
47 UART_LSR_PE | UART_LSR_FE)
48#define TEGRA_UART_IRDA_CSR 0x08
49#define TEGRA_UART_SIR_ENABLED 0x80
50
51#define TEGRA_UART_TX_PIO 1
52#define TEGRA_UART_TX_DMA 2
53#define TEGRA_UART_MIN_DMA 16
54#define TEGRA_UART_FIFO_SIZE 32
55
56/*
57 * Tx fifo trigger level setting in tegra uart is in
58 * reverse way then conventional uart.
59 */
60#define TEGRA_UART_TX_TRIG_16B 0x00
61#define TEGRA_UART_TX_TRIG_8B 0x10
62#define TEGRA_UART_TX_TRIG_4B 0x20
63#define TEGRA_UART_TX_TRIG_1B 0x30
64
65#define TEGRA_UART_MAXIMUM 8
66
67/* Default UART setting when started: 115200 no parity, stop, 8 data bits */
68#define TEGRA_UART_DEFAULT_BAUD 115200
69#define TEGRA_UART_DEFAULT_LSR UART_LCR_WLEN8
70
71/* Tx transfer mode */
72#define TEGRA_TX_PIO 1
73#define TEGRA_TX_DMA 2
74
75#define TEGRA_UART_FCR_IIR_FIFO_EN 0x40
76
77/**
78 * tegra_uart_chip_data: SOC specific data.
79 *
80 * @tx_fifo_full_status: Status flag available for checking tx fifo full.
81 * @allow_txfifo_reset_fifo_mode: allow_tx fifo reset with fifo mode or not.
82 * Tegra30 does not allow this.
83 * @support_clk_src_div: Clock source support the clock divider.
84 */
85struct tegra_uart_chip_data {
86 bool tx_fifo_full_status;
87 bool allow_txfifo_reset_fifo_mode;
88 bool support_clk_src_div;
89 bool fifo_mode_enable_status;
90 int uart_max_port;
91 int max_dma_burst_bytes;
92 int error_tolerance_low_range;
93 int error_tolerance_high_range;
94};
95
96struct tegra_baud_tolerance {
97 u32 lower_range_baud;
98 u32 upper_range_baud;
99 s32 tolerance;
100};
101
102struct tegra_uart_port {
103 struct uart_port uport;
104 const struct tegra_uart_chip_data *cdata;
105
106 struct clk *uart_clk;
107 struct reset_control *rst;
108 unsigned int current_baud;
109
110 /* Register shadow */
111 unsigned long fcr_shadow;
112 unsigned long mcr_shadow;
113 unsigned long lcr_shadow;
114 unsigned long ier_shadow;
115 bool rts_active;
116
117 int tx_in_progress;
118 unsigned int tx_bytes;
119
120 bool enable_modem_interrupt;
121
122 bool rx_timeout;
123 int rx_in_progress;
124 int symb_bit;
125
126 struct dma_chan *rx_dma_chan;
127 struct dma_chan *tx_dma_chan;
128 dma_addr_t rx_dma_buf_phys;
129 dma_addr_t tx_dma_buf_phys;
130 unsigned char *rx_dma_buf_virt;
131 unsigned char *tx_dma_buf_virt;
132 struct dma_async_tx_descriptor *tx_dma_desc;
133 struct dma_async_tx_descriptor *rx_dma_desc;
134 dma_cookie_t tx_cookie;
135 dma_cookie_t rx_cookie;
136 unsigned int tx_bytes_requested;
137 unsigned int rx_bytes_requested;
138 struct tegra_baud_tolerance *baud_tolerance;
139 int n_adjustable_baud_rates;
140 int required_rate;
141 int configured_rate;
142 bool use_rx_pio;
143 bool use_tx_pio;
144 bool rx_dma_active;
145};
146
147static void tegra_uart_start_next_tx(struct tegra_uart_port *tup);
148static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup);
149static void tegra_uart_dma_channel_free(struct tegra_uart_port *tup,
150 bool dma_to_memory);
151
152static inline unsigned long tegra_uart_read(struct tegra_uart_port *tup,
153 unsigned long reg)
154{
155 return readl(tup->uport.membase + (reg << tup->uport.regshift));
156}
157
158static inline void tegra_uart_write(struct tegra_uart_port *tup, unsigned val,
159 unsigned long reg)
160{
161 writel(val, tup->uport.membase + (reg << tup->uport.regshift));
162}
163
164static inline struct tegra_uart_port *to_tegra_uport(struct uart_port *u)
165{
166 return container_of(u, struct tegra_uart_port, uport);
167}
168
169static unsigned int tegra_uart_get_mctrl(struct uart_port *u)
170{
171 struct tegra_uart_port *tup = to_tegra_uport(u);
172
173 /*
174 * RI - Ring detector is active
175 * CD/DCD/CAR - Carrier detect is always active. For some reason
176 * linux has different names for carrier detect.
177 * DSR - Data Set ready is active as the hardware doesn't support it.
178 * Don't know if the linux support this yet?
179 * CTS - Clear to send. Always set to active, as the hardware handles
180 * CTS automatically.
181 */
182 if (tup->enable_modem_interrupt)
183 return TIOCM_RI | TIOCM_CD | TIOCM_DSR | TIOCM_CTS;
184 return TIOCM_CTS;
185}
186
187static void set_rts(struct tegra_uart_port *tup, bool active)
188{
189 unsigned long mcr;
190
191 mcr = tup->mcr_shadow;
192 if (active)
193 mcr |= TEGRA_UART_MCR_RTS_EN;
194 else
195 mcr &= ~TEGRA_UART_MCR_RTS_EN;
196 if (mcr != tup->mcr_shadow) {
197 tegra_uart_write(tup, mcr, UART_MCR);
198 tup->mcr_shadow = mcr;
199 }
200}
201
202static void set_dtr(struct tegra_uart_port *tup, bool active)
203{
204 unsigned long mcr;
205
206 mcr = tup->mcr_shadow;
207 if (active)
208 mcr |= UART_MCR_DTR;
209 else
210 mcr &= ~UART_MCR_DTR;
211 if (mcr != tup->mcr_shadow) {
212 tegra_uart_write(tup, mcr, UART_MCR);
213 tup->mcr_shadow = mcr;
214 }
215}
216
217static void set_loopbk(struct tegra_uart_port *tup, bool active)
218{
219 unsigned long mcr = tup->mcr_shadow;
220
221 if (active)
222 mcr |= UART_MCR_LOOP;
223 else
224 mcr &= ~UART_MCR_LOOP;
225
226 if (mcr != tup->mcr_shadow) {
227 tegra_uart_write(tup, mcr, UART_MCR);
228 tup->mcr_shadow = mcr;
229 }
230}
231
232static void tegra_uart_set_mctrl(struct uart_port *u, unsigned int mctrl)
233{
234 struct tegra_uart_port *tup = to_tegra_uport(u);
235 int enable;
236
237 tup->rts_active = !!(mctrl & TIOCM_RTS);
238 set_rts(tup, tup->rts_active);
239
240 enable = !!(mctrl & TIOCM_DTR);
241 set_dtr(tup, enable);
242
243 enable = !!(mctrl & TIOCM_LOOP);
244 set_loopbk(tup, enable);
245}
246
247static void tegra_uart_break_ctl(struct uart_port *u, int break_ctl)
248{
249 struct tegra_uart_port *tup = to_tegra_uport(u);
250 unsigned long lcr;
251
252 lcr = tup->lcr_shadow;
253 if (break_ctl)
254 lcr |= UART_LCR_SBC;
255 else
256 lcr &= ~UART_LCR_SBC;
257 tegra_uart_write(tup, lcr, UART_LCR);
258 tup->lcr_shadow = lcr;
259}
260
261/**
262 * tegra_uart_wait_cycle_time: Wait for N UART clock periods
263 *
264 * @tup: Tegra serial port data structure.
265 * @cycles: Number of clock periods to wait.
266 *
267 * Tegra UARTs are clocked at 16X the baud/bit rate and hence the UART
268 * clock speed is 16X the current baud rate.
269 */
270static void tegra_uart_wait_cycle_time(struct tegra_uart_port *tup,
271 unsigned int cycles)
272{
273 if (tup->current_baud)
274 udelay(DIV_ROUND_UP(cycles * 1000000, tup->current_baud * 16));
275}
276
277/* Wait for a symbol-time. */
278static void tegra_uart_wait_sym_time(struct tegra_uart_port *tup,
279 unsigned int syms)
280{
281 if (tup->current_baud)
282 udelay(DIV_ROUND_UP(syms * tup->symb_bit * 1000000,
283 tup->current_baud));
284}
285
286static int tegra_uart_wait_fifo_mode_enabled(struct tegra_uart_port *tup)
287{
288 unsigned long iir;
289 unsigned int tmout = 100;
290
291 do {
292 iir = tegra_uart_read(tup, UART_IIR);
293 if (iir & TEGRA_UART_FCR_IIR_FIFO_EN)
294 return 0;
295 udelay(1);
296 } while (--tmout);
297
298 return -ETIMEDOUT;
299}
300
301static void tegra_uart_fifo_reset(struct tegra_uart_port *tup, u8 fcr_bits)
302{
303 unsigned long fcr = tup->fcr_shadow;
304 unsigned int lsr, tmout = 10000;
305
306 if (tup->rts_active)
307 set_rts(tup, false);
308
309 if (tup->cdata->allow_txfifo_reset_fifo_mode) {
310 fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
311 tegra_uart_write(tup, fcr, UART_FCR);
312 } else {
313 fcr &= ~UART_FCR_ENABLE_FIFO;
314 tegra_uart_write(tup, fcr, UART_FCR);
315 udelay(60);
316 fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
317 tegra_uart_write(tup, fcr, UART_FCR);
318 fcr |= UART_FCR_ENABLE_FIFO;
319 tegra_uart_write(tup, fcr, UART_FCR);
320 if (tup->cdata->fifo_mode_enable_status)
321 tegra_uart_wait_fifo_mode_enabled(tup);
322 }
323
324 /* Dummy read to ensure the write is posted */
325 tegra_uart_read(tup, UART_SCR);
326
327 /*
328 * For all tegra devices (up to t210), there is a hardware issue that
329 * requires software to wait for 32 UART clock periods for the flush
330 * to propagate, otherwise data could be lost.
331 */
332 tegra_uart_wait_cycle_time(tup, 32);
333
334 do {
335 lsr = tegra_uart_read(tup, UART_LSR);
336 if ((lsr | UART_LSR_TEMT) && !(lsr & UART_LSR_DR))
337 break;
338 udelay(1);
339 } while (--tmout);
340
341 if (tup->rts_active)
342 set_rts(tup, true);
343}
344
345static long tegra_get_tolerance_rate(struct tegra_uart_port *tup,
346 unsigned int baud, long rate)
347{
348 int i;
349
350 for (i = 0; i < tup->n_adjustable_baud_rates; ++i) {
351 if (baud >= tup->baud_tolerance[i].lower_range_baud &&
352 baud <= tup->baud_tolerance[i].upper_range_baud)
353 return (rate + (rate *
354 tup->baud_tolerance[i].tolerance) / 10000);
355 }
356
357 return rate;
358}
359
360static int tegra_check_rate_in_range(struct tegra_uart_port *tup)
361{
362 long diff;
363
364 diff = ((long)(tup->configured_rate - tup->required_rate) * 10000)
365 / tup->required_rate;
366 if (diff < (tup->cdata->error_tolerance_low_range * 100) ||
367 diff > (tup->cdata->error_tolerance_high_range * 100)) {
368 dev_err(tup->uport.dev,
369 "configured baud rate is out of range by %ld", diff);
370 return -EIO;
371 }
372
373 return 0;
374}
375
376static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud)
377{
378 unsigned long rate;
379 unsigned int divisor;
380 unsigned long lcr;
381 unsigned long flags;
382 int ret;
383
384 if (tup->current_baud == baud)
385 return 0;
386
387 if (tup->cdata->support_clk_src_div) {
388 rate = baud * 16;
389 tup->required_rate = rate;
390
391 if (tup->n_adjustable_baud_rates)
392 rate = tegra_get_tolerance_rate(tup, baud, rate);
393
394 ret = clk_set_rate(tup->uart_clk, rate);
395 if (ret < 0) {
396 dev_err(tup->uport.dev,
397 "clk_set_rate() failed for rate %lu\n", rate);
398 return ret;
399 }
400 tup->configured_rate = clk_get_rate(tup->uart_clk);
401 divisor = 1;
402 ret = tegra_check_rate_in_range(tup);
403 if (ret < 0)
404 return ret;
405 } else {
406 rate = clk_get_rate(tup->uart_clk);
407 divisor = DIV_ROUND_CLOSEST(rate, baud * 16);
408 }
409
410 spin_lock_irqsave(&tup->uport.lock, flags);
411 lcr = tup->lcr_shadow;
412 lcr |= UART_LCR_DLAB;
413 tegra_uart_write(tup, lcr, UART_LCR);
414
415 tegra_uart_write(tup, divisor & 0xFF, UART_TX);
416 tegra_uart_write(tup, ((divisor >> 8) & 0xFF), UART_IER);
417
418 lcr &= ~UART_LCR_DLAB;
419 tegra_uart_write(tup, lcr, UART_LCR);
420
421 /* Dummy read to ensure the write is posted */
422 tegra_uart_read(tup, UART_SCR);
423 spin_unlock_irqrestore(&tup->uport.lock, flags);
424
425 tup->current_baud = baud;
426
427 /* wait two character intervals at new rate */
428 tegra_uart_wait_sym_time(tup, 2);
429 return 0;
430}
431
432static char tegra_uart_decode_rx_error(struct tegra_uart_port *tup,
433 unsigned long lsr)
434{
435 char flag = TTY_NORMAL;
436
437 if (unlikely(lsr & TEGRA_UART_LSR_ANY)) {
438 if (lsr & UART_LSR_OE) {
439 /* Overrrun error */
440 flag = TTY_OVERRUN;
441 tup->uport.icount.overrun++;
442 dev_dbg(tup->uport.dev, "Got overrun errors\n");
443 } else if (lsr & UART_LSR_PE) {
444 /* Parity error */
445 flag = TTY_PARITY;
446 tup->uport.icount.parity++;
447 dev_dbg(tup->uport.dev, "Got Parity errors\n");
448 } else if (lsr & UART_LSR_FE) {
449 flag = TTY_FRAME;
450 tup->uport.icount.frame++;
451 dev_dbg(tup->uport.dev, "Got frame errors\n");
452 } else if (lsr & UART_LSR_BI) {
453 /*
454 * Break error
455 * If FIFO read error without any data, reset Rx FIFO
456 */
457 if (!(lsr & UART_LSR_DR) && (lsr & UART_LSR_FIFOE))
458 tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_RCVR);
459 if (tup->uport.ignore_status_mask & UART_LSR_BI)
460 return TTY_BREAK;
461 flag = TTY_BREAK;
462 tup->uport.icount.brk++;
463 dev_dbg(tup->uport.dev, "Got Break\n");
464 }
465 uart_insert_char(&tup->uport, lsr, UART_LSR_OE, 0, flag);
466 }
467
468 return flag;
469}
470
471static int tegra_uart_request_port(struct uart_port *u)
472{
473 return 0;
474}
475
476static void tegra_uart_release_port(struct uart_port *u)
477{
478 /* Nothing to do here */
479}
480
481static void tegra_uart_fill_tx_fifo(struct tegra_uart_port *tup, int max_bytes)
482{
483 struct circ_buf *xmit = &tup->uport.state->xmit;
484 int i;
485
486 for (i = 0; i < max_bytes; i++) {
487 BUG_ON(uart_circ_empty(xmit));
488 if (tup->cdata->tx_fifo_full_status) {
489 unsigned long lsr = tegra_uart_read(tup, UART_LSR);
490 if ((lsr & TEGRA_UART_LSR_TXFIFO_FULL))
491 break;
492 }
493 tegra_uart_write(tup, xmit->buf[xmit->tail], UART_TX);
494 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
495 tup->uport.icount.tx++;
496 }
497}
498
499static void tegra_uart_start_pio_tx(struct tegra_uart_port *tup,
500 unsigned int bytes)
501{
502 if (bytes > TEGRA_UART_MIN_DMA)
503 bytes = TEGRA_UART_MIN_DMA;
504
505 tup->tx_in_progress = TEGRA_UART_TX_PIO;
506 tup->tx_bytes = bytes;
507 tup->ier_shadow |= UART_IER_THRI;
508 tegra_uart_write(tup, tup->ier_shadow, UART_IER);
509}
510
511static void tegra_uart_tx_dma_complete(void *args)
512{
513 struct tegra_uart_port *tup = args;
514 struct circ_buf *xmit = &tup->uport.state->xmit;
515 struct dma_tx_state state;
516 unsigned long flags;
517 unsigned int count;
518
519 dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state);
520 count = tup->tx_bytes_requested - state.residue;
521 async_tx_ack(tup->tx_dma_desc);
522 spin_lock_irqsave(&tup->uport.lock, flags);
523 xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
524 tup->tx_in_progress = 0;
525 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
526 uart_write_wakeup(&tup->uport);
527 tegra_uart_start_next_tx(tup);
528 spin_unlock_irqrestore(&tup->uport.lock, flags);
529}
530
531static int tegra_uart_start_tx_dma(struct tegra_uart_port *tup,
532 unsigned long count)
533{
534 struct circ_buf *xmit = &tup->uport.state->xmit;
535 dma_addr_t tx_phys_addr;
536
537 tup->tx_bytes = count & ~(0xF);
538 tx_phys_addr = tup->tx_dma_buf_phys + xmit->tail;
539
540 dma_sync_single_for_device(tup->uport.dev, tx_phys_addr,
541 tup->tx_bytes, DMA_TO_DEVICE);
542
543 tup->tx_dma_desc = dmaengine_prep_slave_single(tup->tx_dma_chan,
544 tx_phys_addr, tup->tx_bytes, DMA_MEM_TO_DEV,
545 DMA_PREP_INTERRUPT);
546 if (!tup->tx_dma_desc) {
547 dev_err(tup->uport.dev, "Not able to get desc for Tx\n");
548 return -EIO;
549 }
550
551 tup->tx_dma_desc->callback = tegra_uart_tx_dma_complete;
552 tup->tx_dma_desc->callback_param = tup;
553 tup->tx_in_progress = TEGRA_UART_TX_DMA;
554 tup->tx_bytes_requested = tup->tx_bytes;
555 tup->tx_cookie = dmaengine_submit(tup->tx_dma_desc);
556 dma_async_issue_pending(tup->tx_dma_chan);
557 return 0;
558}
559
560static void tegra_uart_start_next_tx(struct tegra_uart_port *tup)
561{
562 unsigned long tail;
563 unsigned long count;
564 struct circ_buf *xmit = &tup->uport.state->xmit;
565
566 if (!tup->current_baud)
567 return;
568
569 tail = (unsigned long)&xmit->buf[xmit->tail];
570 count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
571 if (!count)
572 return;
573
574 if (tup->use_tx_pio || count < TEGRA_UART_MIN_DMA)
575 tegra_uart_start_pio_tx(tup, count);
576 else if (BYTES_TO_ALIGN(tail) > 0)
577 tegra_uart_start_pio_tx(tup, BYTES_TO_ALIGN(tail));
578 else
579 tegra_uart_start_tx_dma(tup, count);
580}
581
582/* Called by serial core driver with u->lock taken. */
583static void tegra_uart_start_tx(struct uart_port *u)
584{
585 struct tegra_uart_port *tup = to_tegra_uport(u);
586 struct circ_buf *xmit = &u->state->xmit;
587
588 if (!uart_circ_empty(xmit) && !tup->tx_in_progress)
589 tegra_uart_start_next_tx(tup);
590}
591
592static unsigned int tegra_uart_tx_empty(struct uart_port *u)
593{
594 struct tegra_uart_port *tup = to_tegra_uport(u);
595 unsigned int ret = 0;
596 unsigned long flags;
597
598 spin_lock_irqsave(&u->lock, flags);
599 if (!tup->tx_in_progress) {
600 unsigned long lsr = tegra_uart_read(tup, UART_LSR);
601 if ((lsr & TX_EMPTY_STATUS) == TX_EMPTY_STATUS)
602 ret = TIOCSER_TEMT;
603 }
604 spin_unlock_irqrestore(&u->lock, flags);
605 return ret;
606}
607
608static void tegra_uart_stop_tx(struct uart_port *u)
609{
610 struct tegra_uart_port *tup = to_tegra_uport(u);
611 struct circ_buf *xmit = &tup->uport.state->xmit;
612 struct dma_tx_state state;
613 unsigned int count;
614
615 if (tup->tx_in_progress != TEGRA_UART_TX_DMA)
616 return;
617
618 dmaengine_terminate_all(tup->tx_dma_chan);
619 dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state);
620 count = tup->tx_bytes_requested - state.residue;
621 async_tx_ack(tup->tx_dma_desc);
622 xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
623 tup->tx_in_progress = 0;
624}
625
626static void tegra_uart_handle_tx_pio(struct tegra_uart_port *tup)
627{
628 struct circ_buf *xmit = &tup->uport.state->xmit;
629
630 tegra_uart_fill_tx_fifo(tup, tup->tx_bytes);
631 tup->tx_in_progress = 0;
632 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
633 uart_write_wakeup(&tup->uport);
634 tegra_uart_start_next_tx(tup);
635}
636
637static void tegra_uart_handle_rx_pio(struct tegra_uart_port *tup,
638 struct tty_port *port)
639{
640 do {
641 char flag = TTY_NORMAL;
642 unsigned long lsr = 0;
643 unsigned char ch;
644
645 lsr = tegra_uart_read(tup, UART_LSR);
646 if (!(lsr & UART_LSR_DR))
647 break;
648
649 flag = tegra_uart_decode_rx_error(tup, lsr);
650 if (flag != TTY_NORMAL)
651 continue;
652
653 ch = (unsigned char) tegra_uart_read(tup, UART_RX);
654 tup->uport.icount.rx++;
655
656 if (uart_handle_sysrq_char(&tup->uport, ch))
657 continue;
658
659 if (tup->uport.ignore_status_mask & UART_LSR_DR)
660 continue;
661
662 tty_insert_flip_char(port, ch, flag);
663 } while (1);
664}
665
666static void tegra_uart_copy_rx_to_tty(struct tegra_uart_port *tup,
667 struct tty_port *port,
668 unsigned int count)
669{
670 int copied;
671
672 /* If count is zero, then there is no data to be copied */
673 if (!count)
674 return;
675
676 tup->uport.icount.rx += count;
677
678 if (tup->uport.ignore_status_mask & UART_LSR_DR)
679 return;
680
681 dma_sync_single_for_cpu(tup->uport.dev, tup->rx_dma_buf_phys,
682 count, DMA_FROM_DEVICE);
683 copied = tty_insert_flip_string(port,
684 ((unsigned char *)(tup->rx_dma_buf_virt)), count);
685 if (copied != count) {
686 WARN_ON(1);
687 dev_err(tup->uport.dev, "RxData copy to tty layer failed\n");
688 }
689 dma_sync_single_for_device(tup->uport.dev, tup->rx_dma_buf_phys,
690 count, DMA_TO_DEVICE);
691}
692
693static void do_handle_rx_pio(struct tegra_uart_port *tup)
694{
695 struct tty_struct *tty = tty_port_tty_get(&tup->uport.state->port);
696 struct tty_port *port = &tup->uport.state->port;
697
698 tegra_uart_handle_rx_pio(tup, port);
699 if (tty) {
700 tty_flip_buffer_push(port);
701 tty_kref_put(tty);
702 }
703}
704
705static void tegra_uart_rx_buffer_push(struct tegra_uart_port *tup,
706 unsigned int residue)
707{
708 struct tty_port *port = &tup->uport.state->port;
709 unsigned int count;
710
711 async_tx_ack(tup->rx_dma_desc);
712 count = tup->rx_bytes_requested - residue;
713
714 /* If we are here, DMA is stopped */
715 tegra_uart_copy_rx_to_tty(tup, port, count);
716
717 do_handle_rx_pio(tup);
718}
719
720static void tegra_uart_rx_dma_complete(void *args)
721{
722 struct tegra_uart_port *tup = args;
723 struct uart_port *u = &tup->uport;
724 unsigned long flags;
725 struct dma_tx_state state;
726 enum dma_status status;
727
728 spin_lock_irqsave(&u->lock, flags);
729
730 status = dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
731
732 if (status == DMA_IN_PROGRESS) {
733 dev_dbg(tup->uport.dev, "RX DMA is in progress\n");
734 goto done;
735 }
736
737 /* Deactivate flow control to stop sender */
738 if (tup->rts_active)
739 set_rts(tup, false);
740
741 tup->rx_dma_active = false;
742 tegra_uart_rx_buffer_push(tup, 0);
743 tegra_uart_start_rx_dma(tup);
744
745 /* Activate flow control to start transfer */
746 if (tup->rts_active)
747 set_rts(tup, true);
748
749done:
750 spin_unlock_irqrestore(&u->lock, flags);
751}
752
753static void tegra_uart_terminate_rx_dma(struct tegra_uart_port *tup)
754{
755 struct dma_tx_state state;
756
757 if (!tup->rx_dma_active) {
758 do_handle_rx_pio(tup);
759 return;
760 }
761
762 dmaengine_terminate_all(tup->rx_dma_chan);
763 dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
764
765 tegra_uart_rx_buffer_push(tup, state.residue);
766 tup->rx_dma_active = false;
767}
768
769static void tegra_uart_handle_rx_dma(struct tegra_uart_port *tup)
770{
771 /* Deactivate flow control to stop sender */
772 if (tup->rts_active)
773 set_rts(tup, false);
774
775 tegra_uart_terminate_rx_dma(tup);
776
777 if (tup->rts_active)
778 set_rts(tup, true);
779}
780
781static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup)
782{
783 unsigned int count = TEGRA_UART_RX_DMA_BUFFER_SIZE;
784
785 if (tup->rx_dma_active)
786 return 0;
787
788 tup->rx_dma_desc = dmaengine_prep_slave_single(tup->rx_dma_chan,
789 tup->rx_dma_buf_phys, count, DMA_DEV_TO_MEM,
790 DMA_PREP_INTERRUPT);
791 if (!tup->rx_dma_desc) {
792 dev_err(tup->uport.dev, "Not able to get desc for Rx\n");
793 return -EIO;
794 }
795
796 tup->rx_dma_active = true;
797 tup->rx_dma_desc->callback = tegra_uart_rx_dma_complete;
798 tup->rx_dma_desc->callback_param = tup;
799 tup->rx_bytes_requested = count;
800 tup->rx_cookie = dmaengine_submit(tup->rx_dma_desc);
801 dma_async_issue_pending(tup->rx_dma_chan);
802 return 0;
803}
804
805static void tegra_uart_handle_modem_signal_change(struct uart_port *u)
806{
807 struct tegra_uart_port *tup = to_tegra_uport(u);
808 unsigned long msr;
809
810 msr = tegra_uart_read(tup, UART_MSR);
811 if (!(msr & UART_MSR_ANY_DELTA))
812 return;
813
814 if (msr & UART_MSR_TERI)
815 tup->uport.icount.rng++;
816 if (msr & UART_MSR_DDSR)
817 tup->uport.icount.dsr++;
818 /* We may only get DDCD when HW init and reset */
819 if (msr & UART_MSR_DDCD)
820 uart_handle_dcd_change(&tup->uport, msr & UART_MSR_DCD);
821 /* Will start/stop_tx accordingly */
822 if (msr & UART_MSR_DCTS)
823 uart_handle_cts_change(&tup->uport, msr & UART_MSR_CTS);
824}
825
826static irqreturn_t tegra_uart_isr(int irq, void *data)
827{
828 struct tegra_uart_port *tup = data;
829 struct uart_port *u = &tup->uport;
830 unsigned long iir;
831 unsigned long ier;
832 bool is_rx_start = false;
833 bool is_rx_int = false;
834 unsigned long flags;
835
836 spin_lock_irqsave(&u->lock, flags);
837 while (1) {
838 iir = tegra_uart_read(tup, UART_IIR);
839 if (iir & UART_IIR_NO_INT) {
840 if (!tup->use_rx_pio && is_rx_int) {
841 tegra_uart_handle_rx_dma(tup);
842 if (tup->rx_in_progress) {
843 ier = tup->ier_shadow;
844 ier |= (UART_IER_RLSI | UART_IER_RTOIE |
845 TEGRA_UART_IER_EORD | UART_IER_RDI);
846 tup->ier_shadow = ier;
847 tegra_uart_write(tup, ier, UART_IER);
848 }
849 } else if (is_rx_start) {
850 tegra_uart_start_rx_dma(tup);
851 }
852 spin_unlock_irqrestore(&u->lock, flags);
853 return IRQ_HANDLED;
854 }
855
856 switch ((iir >> 1) & 0x7) {
857 case 0: /* Modem signal change interrupt */
858 tegra_uart_handle_modem_signal_change(u);
859 break;
860
861 case 1: /* Transmit interrupt only triggered when using PIO */
862 tup->ier_shadow &= ~UART_IER_THRI;
863 tegra_uart_write(tup, tup->ier_shadow, UART_IER);
864 tegra_uart_handle_tx_pio(tup);
865 break;
866
867 case 4: /* End of data */
868 case 6: /* Rx timeout */
869 if (!tup->use_rx_pio) {
870 is_rx_int = tup->rx_in_progress;
871 /* Disable Rx interrupts */
872 ier = tup->ier_shadow;
873 ier &= ~(UART_IER_RDI | UART_IER_RLSI |
874 UART_IER_RTOIE | TEGRA_UART_IER_EORD);
875 tup->ier_shadow = ier;
876 tegra_uart_write(tup, ier, UART_IER);
877 break;
878 }
879 fallthrough;
880 case 2: /* Receive */
881 if (!tup->use_rx_pio) {
882 is_rx_start = tup->rx_in_progress;
883 tup->ier_shadow &= ~UART_IER_RDI;
884 tegra_uart_write(tup, tup->ier_shadow,
885 UART_IER);
886 } else {
887 do_handle_rx_pio(tup);
888 }
889 break;
890
891 case 3: /* Receive error */
892 tegra_uart_decode_rx_error(tup,
893 tegra_uart_read(tup, UART_LSR));
894 break;
895
896 case 5: /* break nothing to handle */
897 case 7: /* break nothing to handle */
898 break;
899 }
900 }
901}
902
903static void tegra_uart_stop_rx(struct uart_port *u)
904{
905 struct tegra_uart_port *tup = to_tegra_uport(u);
906 struct tty_port *port = &tup->uport.state->port;
907 unsigned long ier;
908
909 if (tup->rts_active)
910 set_rts(tup, false);
911
912 if (!tup->rx_in_progress)
913 return;
914
915 tegra_uart_wait_sym_time(tup, 1); /* wait one character interval */
916
917 ier = tup->ier_shadow;
918 ier &= ~(UART_IER_RDI | UART_IER_RLSI | UART_IER_RTOIE |
919 TEGRA_UART_IER_EORD);
920 tup->ier_shadow = ier;
921 tegra_uart_write(tup, ier, UART_IER);
922 tup->rx_in_progress = 0;
923
924 if (!tup->use_rx_pio)
925 tegra_uart_terminate_rx_dma(tup);
926 else
927 tegra_uart_handle_rx_pio(tup, port);
928}
929
930static void tegra_uart_hw_deinit(struct tegra_uart_port *tup)
931{
932 unsigned long flags;
933 unsigned long char_time = DIV_ROUND_UP(10000000, tup->current_baud);
934 unsigned long fifo_empty_time = tup->uport.fifosize * char_time;
935 unsigned long wait_time;
936 unsigned long lsr;
937 unsigned long msr;
938 unsigned long mcr;
939
940 /* Disable interrupts */
941 tegra_uart_write(tup, 0, UART_IER);
942
943 lsr = tegra_uart_read(tup, UART_LSR);
944 if ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) {
945 msr = tegra_uart_read(tup, UART_MSR);
946 mcr = tegra_uart_read(tup, UART_MCR);
947 if ((mcr & TEGRA_UART_MCR_CTS_EN) && (msr & UART_MSR_CTS))
948 dev_err(tup->uport.dev,
949 "Tx Fifo not empty, CTS disabled, waiting\n");
950
951 /* Wait for Tx fifo to be empty */
952 while ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) {
953 wait_time = min(fifo_empty_time, 100lu);
954 udelay(wait_time);
955 fifo_empty_time -= wait_time;
956 if (!fifo_empty_time) {
957 msr = tegra_uart_read(tup, UART_MSR);
958 mcr = tegra_uart_read(tup, UART_MCR);
959 if ((mcr & TEGRA_UART_MCR_CTS_EN) &&
960 (msr & UART_MSR_CTS))
961 dev_err(tup->uport.dev,
962 "Slave not ready\n");
963 break;
964 }
965 lsr = tegra_uart_read(tup, UART_LSR);
966 }
967 }
968
969 spin_lock_irqsave(&tup->uport.lock, flags);
970 /* Reset the Rx and Tx FIFOs */
971 tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_XMIT | UART_FCR_CLEAR_RCVR);
972 tup->current_baud = 0;
973 spin_unlock_irqrestore(&tup->uport.lock, flags);
974
975 tup->rx_in_progress = 0;
976 tup->tx_in_progress = 0;
977
978 if (!tup->use_rx_pio)
979 tegra_uart_dma_channel_free(tup, true);
980 if (!tup->use_tx_pio)
981 tegra_uart_dma_channel_free(tup, false);
982
983 clk_disable_unprepare(tup->uart_clk);
984}
985
986static int tegra_uart_hw_init(struct tegra_uart_port *tup)
987{
988 int ret;
989
990 tup->fcr_shadow = 0;
991 tup->mcr_shadow = 0;
992 tup->lcr_shadow = 0;
993 tup->ier_shadow = 0;
994 tup->current_baud = 0;
995
996 clk_prepare_enable(tup->uart_clk);
997
998 /* Reset the UART controller to clear all previous status.*/
999 reset_control_assert(tup->rst);
1000 udelay(10);
1001 reset_control_deassert(tup->rst);
1002
1003 tup->rx_in_progress = 0;
1004 tup->tx_in_progress = 0;
1005
1006 /*
1007 * Set the trigger level
1008 *
1009 * For PIO mode:
1010 *
1011 * For receive, this will interrupt the CPU after that many number of
1012 * bytes are received, for the remaining bytes the receive timeout
1013 * interrupt is received. Rx high watermark is set to 4.
1014 *
1015 * For transmit, if the trasnmit interrupt is enabled, this will
1016 * interrupt the CPU when the number of entries in the FIFO reaches the
1017 * low watermark. Tx low watermark is set to 16 bytes.
1018 *
1019 * For DMA mode:
1020 *
1021 * Set the Tx trigger to 16. This should match the DMA burst size that
1022 * programmed in the DMA registers.
1023 */
1024 tup->fcr_shadow = UART_FCR_ENABLE_FIFO;
1025
1026 if (tup->use_rx_pio) {
1027 tup->fcr_shadow |= UART_FCR_R_TRIG_11;
1028 } else {
1029 if (tup->cdata->max_dma_burst_bytes == 8)
1030 tup->fcr_shadow |= UART_FCR_R_TRIG_10;
1031 else
1032 tup->fcr_shadow |= UART_FCR_R_TRIG_01;
1033 }
1034
1035 tup->fcr_shadow |= TEGRA_UART_TX_TRIG_16B;
1036 tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
1037
1038 /* Dummy read to ensure the write is posted */
1039 tegra_uart_read(tup, UART_SCR);
1040
1041 if (tup->cdata->fifo_mode_enable_status) {
1042 ret = tegra_uart_wait_fifo_mode_enabled(tup);
1043 dev_err(tup->uport.dev, "FIFO mode not enabled\n");
1044 if (ret < 0)
1045 return ret;
1046 } else {
1047 /*
1048 * For all tegra devices (up to t210), there is a hardware
1049 * issue that requires software to wait for 3 UART clock
1050 * periods after enabling the TX fifo, otherwise data could
1051 * be lost.
1052 */
1053 tegra_uart_wait_cycle_time(tup, 3);
1054 }
1055
1056 /*
1057 * Initialize the UART with default configuration
1058 * (115200, N, 8, 1) so that the receive DMA buffer may be
1059 * enqueued
1060 */
1061 ret = tegra_set_baudrate(tup, TEGRA_UART_DEFAULT_BAUD);
1062 if (ret < 0) {
1063 dev_err(tup->uport.dev, "Failed to set baud rate\n");
1064 return ret;
1065 }
1066 if (!tup->use_rx_pio) {
1067 tup->lcr_shadow = TEGRA_UART_DEFAULT_LSR;
1068 tup->fcr_shadow |= UART_FCR_DMA_SELECT;
1069 tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
1070 } else {
1071 tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
1072 }
1073 tup->rx_in_progress = 1;
1074
1075 /*
1076 * Enable IE_RXS for the receive status interrupts like line errros.
1077 * Enable IE_RX_TIMEOUT to get the bytes which cannot be DMA'd.
1078 *
1079 * EORD is different interrupt than RX_TIMEOUT - RX_TIMEOUT occurs when
1080 * the DATA is sitting in the FIFO and couldn't be transferred to the
1081 * DMA as the DMA size alignment (4 bytes) is not met. EORD will be
1082 * triggered when there is a pause of the incomming data stream for 4
1083 * characters long.
1084 *
1085 * For pauses in the data which is not aligned to 4 bytes, we get
1086 * both the EORD as well as RX_TIMEOUT - SW sees RX_TIMEOUT first
1087 * then the EORD.
1088 */
1089 tup->ier_shadow = UART_IER_RLSI | UART_IER_RTOIE | UART_IER_RDI;
1090
1091 /*
1092 * If using DMA mode, enable EORD interrupt to notify about RX
1093 * completion.
1094 */
1095 if (!tup->use_rx_pio)
1096 tup->ier_shadow |= TEGRA_UART_IER_EORD;
1097
1098 tegra_uart_write(tup, tup->ier_shadow, UART_IER);
1099 return 0;
1100}
1101
1102static void tegra_uart_dma_channel_free(struct tegra_uart_port *tup,
1103 bool dma_to_memory)
1104{
1105 if (dma_to_memory) {
1106 dmaengine_terminate_all(tup->rx_dma_chan);
1107 dma_release_channel(tup->rx_dma_chan);
1108 dma_free_coherent(tup->uport.dev, TEGRA_UART_RX_DMA_BUFFER_SIZE,
1109 tup->rx_dma_buf_virt, tup->rx_dma_buf_phys);
1110 tup->rx_dma_chan = NULL;
1111 tup->rx_dma_buf_phys = 0;
1112 tup->rx_dma_buf_virt = NULL;
1113 } else {
1114 dmaengine_terminate_all(tup->tx_dma_chan);
1115 dma_release_channel(tup->tx_dma_chan);
1116 dma_unmap_single(tup->uport.dev, tup->tx_dma_buf_phys,
1117 UART_XMIT_SIZE, DMA_TO_DEVICE);
1118 tup->tx_dma_chan = NULL;
1119 tup->tx_dma_buf_phys = 0;
1120 tup->tx_dma_buf_virt = NULL;
1121 }
1122}
1123
1124static int tegra_uart_dma_channel_allocate(struct tegra_uart_port *tup,
1125 bool dma_to_memory)
1126{
1127 struct dma_chan *dma_chan;
1128 unsigned char *dma_buf;
1129 dma_addr_t dma_phys;
1130 int ret;
1131 struct dma_slave_config dma_sconfig;
1132
1133 dma_chan = dma_request_chan(tup->uport.dev, dma_to_memory ? "rx" : "tx");
1134 if (IS_ERR(dma_chan)) {
1135 ret = PTR_ERR(dma_chan);
1136 dev_err(tup->uport.dev,
1137 "DMA channel alloc failed: %d\n", ret);
1138 return ret;
1139 }
1140
1141 if (dma_to_memory) {
1142 dma_buf = dma_alloc_coherent(tup->uport.dev,
1143 TEGRA_UART_RX_DMA_BUFFER_SIZE,
1144 &dma_phys, GFP_KERNEL);
1145 if (!dma_buf) {
1146 dev_err(tup->uport.dev,
1147 "Not able to allocate the dma buffer\n");
1148 dma_release_channel(dma_chan);
1149 return -ENOMEM;
1150 }
1151 dma_sync_single_for_device(tup->uport.dev, dma_phys,
1152 TEGRA_UART_RX_DMA_BUFFER_SIZE,
1153 DMA_TO_DEVICE);
1154 dma_sconfig.src_addr = tup->uport.mapbase;
1155 dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1156 dma_sconfig.src_maxburst = tup->cdata->max_dma_burst_bytes;
1157 tup->rx_dma_chan = dma_chan;
1158 tup->rx_dma_buf_virt = dma_buf;
1159 tup->rx_dma_buf_phys = dma_phys;
1160 } else {
1161 dma_phys = dma_map_single(tup->uport.dev,
1162 tup->uport.state->xmit.buf, UART_XMIT_SIZE,
1163 DMA_TO_DEVICE);
1164 if (dma_mapping_error(tup->uport.dev, dma_phys)) {
1165 dev_err(tup->uport.dev, "dma_map_single tx failed\n");
1166 dma_release_channel(dma_chan);
1167 return -ENOMEM;
1168 }
1169 dma_buf = tup->uport.state->xmit.buf;
1170 dma_sconfig.dst_addr = tup->uport.mapbase;
1171 dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1172 dma_sconfig.dst_maxburst = 16;
1173 tup->tx_dma_chan = dma_chan;
1174 tup->tx_dma_buf_virt = dma_buf;
1175 tup->tx_dma_buf_phys = dma_phys;
1176 }
1177
1178 ret = dmaengine_slave_config(dma_chan, &dma_sconfig);
1179 if (ret < 0) {
1180 dev_err(tup->uport.dev,
1181 "Dma slave config failed, err = %d\n", ret);
1182 tegra_uart_dma_channel_free(tup, dma_to_memory);
1183 return ret;
1184 }
1185
1186 return 0;
1187}
1188
1189static int tegra_uart_startup(struct uart_port *u)
1190{
1191 struct tegra_uart_port *tup = to_tegra_uport(u);
1192 int ret;
1193
1194 if (!tup->use_tx_pio) {
1195 ret = tegra_uart_dma_channel_allocate(tup, false);
1196 if (ret < 0) {
1197 dev_err(u->dev, "Tx Dma allocation failed, err = %d\n",
1198 ret);
1199 return ret;
1200 }
1201 }
1202
1203 if (!tup->use_rx_pio) {
1204 ret = tegra_uart_dma_channel_allocate(tup, true);
1205 if (ret < 0) {
1206 dev_err(u->dev, "Rx Dma allocation failed, err = %d\n",
1207 ret);
1208 goto fail_rx_dma;
1209 }
1210 }
1211
1212 ret = tegra_uart_hw_init(tup);
1213 if (ret < 0) {
1214 dev_err(u->dev, "Uart HW init failed, err = %d\n", ret);
1215 goto fail_hw_init;
1216 }
1217
1218 ret = request_irq(u->irq, tegra_uart_isr, 0,
1219 dev_name(u->dev), tup);
1220 if (ret < 0) {
1221 dev_err(u->dev, "Failed to register ISR for IRQ %d\n", u->irq);
1222 goto fail_hw_init;
1223 }
1224 return 0;
1225
1226fail_hw_init:
1227 if (!tup->use_rx_pio)
1228 tegra_uart_dma_channel_free(tup, true);
1229fail_rx_dma:
1230 if (!tup->use_tx_pio)
1231 tegra_uart_dma_channel_free(tup, false);
1232 return ret;
1233}
1234
1235/*
1236 * Flush any TX data submitted for DMA and PIO. Called when the
1237 * TX circular buffer is reset.
1238 */
1239static void tegra_uart_flush_buffer(struct uart_port *u)
1240{
1241 struct tegra_uart_port *tup = to_tegra_uport(u);
1242
1243 tup->tx_bytes = 0;
1244 if (tup->tx_dma_chan)
1245 dmaengine_terminate_all(tup->tx_dma_chan);
1246}
1247
1248static void tegra_uart_shutdown(struct uart_port *u)
1249{
1250 struct tegra_uart_port *tup = to_tegra_uport(u);
1251
1252 tegra_uart_hw_deinit(tup);
1253 free_irq(u->irq, tup);
1254}
1255
1256static void tegra_uart_enable_ms(struct uart_port *u)
1257{
1258 struct tegra_uart_port *tup = to_tegra_uport(u);
1259
1260 if (tup->enable_modem_interrupt) {
1261 tup->ier_shadow |= UART_IER_MSI;
1262 tegra_uart_write(tup, tup->ier_shadow, UART_IER);
1263 }
1264}
1265
1266static void tegra_uart_set_termios(struct uart_port *u,
1267 struct ktermios *termios, struct ktermios *oldtermios)
1268{
1269 struct tegra_uart_port *tup = to_tegra_uport(u);
1270 unsigned int baud;
1271 unsigned long flags;
1272 unsigned int lcr;
1273 int symb_bit = 1;
1274 struct clk *parent_clk = clk_get_parent(tup->uart_clk);
1275 unsigned long parent_clk_rate = clk_get_rate(parent_clk);
1276 int max_divider = (tup->cdata->support_clk_src_div) ? 0x7FFF : 0xFFFF;
1277 int ret;
1278
1279 max_divider *= 16;
1280 spin_lock_irqsave(&u->lock, flags);
1281
1282 /* Changing configuration, it is safe to stop any rx now */
1283 if (tup->rts_active)
1284 set_rts(tup, false);
1285
1286 /* Clear all interrupts as configuration is going to be changed */
1287 tegra_uart_write(tup, tup->ier_shadow | UART_IER_RDI, UART_IER);
1288 tegra_uart_read(tup, UART_IER);
1289 tegra_uart_write(tup, 0, UART_IER);
1290 tegra_uart_read(tup, UART_IER);
1291
1292 /* Parity */
1293 lcr = tup->lcr_shadow;
1294 lcr &= ~UART_LCR_PARITY;
1295
1296 /* CMSPAR isn't supported by this driver */
1297 termios->c_cflag &= ~CMSPAR;
1298
1299 if ((termios->c_cflag & PARENB) == PARENB) {
1300 symb_bit++;
1301 if (termios->c_cflag & PARODD) {
1302 lcr |= UART_LCR_PARITY;
1303 lcr &= ~UART_LCR_EPAR;
1304 lcr &= ~UART_LCR_SPAR;
1305 } else {
1306 lcr |= UART_LCR_PARITY;
1307 lcr |= UART_LCR_EPAR;
1308 lcr &= ~UART_LCR_SPAR;
1309 }
1310 }
1311
1312 lcr &= ~UART_LCR_WLEN8;
1313 switch (termios->c_cflag & CSIZE) {
1314 case CS5:
1315 lcr |= UART_LCR_WLEN5;
1316 symb_bit += 5;
1317 break;
1318 case CS6:
1319 lcr |= UART_LCR_WLEN6;
1320 symb_bit += 6;
1321 break;
1322 case CS7:
1323 lcr |= UART_LCR_WLEN7;
1324 symb_bit += 7;
1325 break;
1326 default:
1327 lcr |= UART_LCR_WLEN8;
1328 symb_bit += 8;
1329 break;
1330 }
1331
1332 /* Stop bits */
1333 if (termios->c_cflag & CSTOPB) {
1334 lcr |= UART_LCR_STOP;
1335 symb_bit += 2;
1336 } else {
1337 lcr &= ~UART_LCR_STOP;
1338 symb_bit++;
1339 }
1340
1341 tegra_uart_write(tup, lcr, UART_LCR);
1342 tup->lcr_shadow = lcr;
1343 tup->symb_bit = symb_bit;
1344
1345 /* Baud rate. */
1346 baud = uart_get_baud_rate(u, termios, oldtermios,
1347 parent_clk_rate/max_divider,
1348 parent_clk_rate/16);
1349 spin_unlock_irqrestore(&u->lock, flags);
1350 ret = tegra_set_baudrate(tup, baud);
1351 if (ret < 0) {
1352 dev_err(tup->uport.dev, "Failed to set baud rate\n");
1353 return;
1354 }
1355 if (tty_termios_baud_rate(termios))
1356 tty_termios_encode_baud_rate(termios, baud, baud);
1357 spin_lock_irqsave(&u->lock, flags);
1358
1359 /* Flow control */
1360 if (termios->c_cflag & CRTSCTS) {
1361 tup->mcr_shadow |= TEGRA_UART_MCR_CTS_EN;
1362 tup->mcr_shadow &= ~TEGRA_UART_MCR_RTS_EN;
1363 tegra_uart_write(tup, tup->mcr_shadow, UART_MCR);
1364 /* if top layer has asked to set rts active then do so here */
1365 if (tup->rts_active)
1366 set_rts(tup, true);
1367 } else {
1368 tup->mcr_shadow &= ~TEGRA_UART_MCR_CTS_EN;
1369 tup->mcr_shadow &= ~TEGRA_UART_MCR_RTS_EN;
1370 tegra_uart_write(tup, tup->mcr_shadow, UART_MCR);
1371 }
1372
1373 /* update the port timeout based on new settings */
1374 uart_update_timeout(u, termios->c_cflag, baud);
1375
1376 /* Make sure all writes have completed */
1377 tegra_uart_read(tup, UART_IER);
1378
1379 /* Re-enable interrupt */
1380 tegra_uart_write(tup, tup->ier_shadow, UART_IER);
1381 tegra_uart_read(tup, UART_IER);
1382
1383 tup->uport.ignore_status_mask = 0;
1384 /* Ignore all characters if CREAD is not set */
1385 if ((termios->c_cflag & CREAD) == 0)
1386 tup->uport.ignore_status_mask |= UART_LSR_DR;
1387 if (termios->c_iflag & IGNBRK)
1388 tup->uport.ignore_status_mask |= UART_LSR_BI;
1389
1390 spin_unlock_irqrestore(&u->lock, flags);
1391}
1392
1393static const char *tegra_uart_type(struct uart_port *u)
1394{
1395 return TEGRA_UART_TYPE;
1396}
1397
1398static const struct uart_ops tegra_uart_ops = {
1399 .tx_empty = tegra_uart_tx_empty,
1400 .set_mctrl = tegra_uart_set_mctrl,
1401 .get_mctrl = tegra_uart_get_mctrl,
1402 .stop_tx = tegra_uart_stop_tx,
1403 .start_tx = tegra_uart_start_tx,
1404 .stop_rx = tegra_uart_stop_rx,
1405 .flush_buffer = tegra_uart_flush_buffer,
1406 .enable_ms = tegra_uart_enable_ms,
1407 .break_ctl = tegra_uart_break_ctl,
1408 .startup = tegra_uart_startup,
1409 .shutdown = tegra_uart_shutdown,
1410 .set_termios = tegra_uart_set_termios,
1411 .type = tegra_uart_type,
1412 .request_port = tegra_uart_request_port,
1413 .release_port = tegra_uart_release_port,
1414};
1415
1416static struct uart_driver tegra_uart_driver = {
1417 .owner = THIS_MODULE,
1418 .driver_name = "tegra_hsuart",
1419 .dev_name = "ttyTHS",
1420 .cons = NULL,
1421 .nr = TEGRA_UART_MAXIMUM,
1422};
1423
1424static int tegra_uart_parse_dt(struct platform_device *pdev,
1425 struct tegra_uart_port *tup)
1426{
1427 struct device_node *np = pdev->dev.of_node;
1428 int port;
1429 int ret;
1430 int index;
1431 u32 pval;
1432 int count;
1433 int n_entries;
1434
1435 port = of_alias_get_id(np, "serial");
1436 if (port < 0) {
1437 dev_err(&pdev->dev, "failed to get alias id, errno %d\n", port);
1438 return port;
1439 }
1440 tup->uport.line = port;
1441
1442 tup->enable_modem_interrupt = of_property_read_bool(np,
1443 "nvidia,enable-modem-interrupt");
1444
1445 index = of_property_match_string(np, "dma-names", "rx");
1446 if (index < 0) {
1447 tup->use_rx_pio = true;
1448 dev_info(&pdev->dev, "RX in PIO mode\n");
1449 }
1450 index = of_property_match_string(np, "dma-names", "tx");
1451 if (index < 0) {
1452 tup->use_tx_pio = true;
1453 dev_info(&pdev->dev, "TX in PIO mode\n");
1454 }
1455
1456 n_entries = of_property_count_u32_elems(np, "nvidia,adjust-baud-rates");
1457 if (n_entries > 0) {
1458 tup->n_adjustable_baud_rates = n_entries / 3;
1459 tup->baud_tolerance =
1460 devm_kzalloc(&pdev->dev, (tup->n_adjustable_baud_rates) *
1461 sizeof(*tup->baud_tolerance), GFP_KERNEL);
1462 if (!tup->baud_tolerance)
1463 return -ENOMEM;
1464 for (count = 0, index = 0; count < n_entries; count += 3,
1465 index++) {
1466 ret =
1467 of_property_read_u32_index(np,
1468 "nvidia,adjust-baud-rates",
1469 count, &pval);
1470 if (!ret)
1471 tup->baud_tolerance[index].lower_range_baud =
1472 pval;
1473 ret =
1474 of_property_read_u32_index(np,
1475 "nvidia,adjust-baud-rates",
1476 count + 1, &pval);
1477 if (!ret)
1478 tup->baud_tolerance[index].upper_range_baud =
1479 pval;
1480 ret =
1481 of_property_read_u32_index(np,
1482 "nvidia,adjust-baud-rates",
1483 count + 2, &pval);
1484 if (!ret)
1485 tup->baud_tolerance[index].tolerance =
1486 (s32)pval;
1487 }
1488 } else {
1489 tup->n_adjustable_baud_rates = 0;
1490 }
1491
1492 return 0;
1493}
1494
1495static struct tegra_uart_chip_data tegra20_uart_chip_data = {
1496 .tx_fifo_full_status = false,
1497 .allow_txfifo_reset_fifo_mode = true,
1498 .support_clk_src_div = false,
1499 .fifo_mode_enable_status = false,
1500 .uart_max_port = 5,
1501 .max_dma_burst_bytes = 4,
1502 .error_tolerance_low_range = 0,
1503 .error_tolerance_high_range = 4,
1504};
1505
1506static struct tegra_uart_chip_data tegra30_uart_chip_data = {
1507 .tx_fifo_full_status = true,
1508 .allow_txfifo_reset_fifo_mode = false,
1509 .support_clk_src_div = true,
1510 .fifo_mode_enable_status = false,
1511 .uart_max_port = 5,
1512 .max_dma_burst_bytes = 4,
1513 .error_tolerance_low_range = 0,
1514 .error_tolerance_high_range = 4,
1515};
1516
1517static struct tegra_uart_chip_data tegra186_uart_chip_data = {
1518 .tx_fifo_full_status = true,
1519 .allow_txfifo_reset_fifo_mode = false,
1520 .support_clk_src_div = true,
1521 .fifo_mode_enable_status = true,
1522 .uart_max_port = 8,
1523 .max_dma_burst_bytes = 8,
1524 .error_tolerance_low_range = 0,
1525 .error_tolerance_high_range = 4,
1526};
1527
1528static struct tegra_uart_chip_data tegra194_uart_chip_data = {
1529 .tx_fifo_full_status = true,
1530 .allow_txfifo_reset_fifo_mode = false,
1531 .support_clk_src_div = true,
1532 .fifo_mode_enable_status = true,
1533 .uart_max_port = 8,
1534 .max_dma_burst_bytes = 8,
1535 .error_tolerance_low_range = -2,
1536 .error_tolerance_high_range = 2,
1537};
1538
1539static const struct of_device_id tegra_uart_of_match[] = {
1540 {
1541 .compatible = "nvidia,tegra30-hsuart",
1542 .data = &tegra30_uart_chip_data,
1543 }, {
1544 .compatible = "nvidia,tegra20-hsuart",
1545 .data = &tegra20_uart_chip_data,
1546 }, {
1547 .compatible = "nvidia,tegra186-hsuart",
1548 .data = &tegra186_uart_chip_data,
1549 }, {
1550 .compatible = "nvidia,tegra194-hsuart",
1551 .data = &tegra194_uart_chip_data,
1552 }, {
1553 },
1554};
1555MODULE_DEVICE_TABLE(of, tegra_uart_of_match);
1556
1557static int tegra_uart_probe(struct platform_device *pdev)
1558{
1559 struct tegra_uart_port *tup;
1560 struct uart_port *u;
1561 struct resource *resource;
1562 int ret;
1563 const struct tegra_uart_chip_data *cdata;
1564 const struct of_device_id *match;
1565
1566 match = of_match_device(tegra_uart_of_match, &pdev->dev);
1567 if (!match) {
1568 dev_err(&pdev->dev, "Error: No device match found\n");
1569 return -ENODEV;
1570 }
1571 cdata = match->data;
1572
1573 tup = devm_kzalloc(&pdev->dev, sizeof(*tup), GFP_KERNEL);
1574 if (!tup) {
1575 dev_err(&pdev->dev, "Failed to allocate memory for tup\n");
1576 return -ENOMEM;
1577 }
1578
1579 ret = tegra_uart_parse_dt(pdev, tup);
1580 if (ret < 0)
1581 return ret;
1582
1583 u = &tup->uport;
1584 u->dev = &pdev->dev;
1585 u->ops = &tegra_uart_ops;
1586 u->type = PORT_TEGRA;
1587 u->fifosize = 32;
1588 tup->cdata = cdata;
1589
1590 platform_set_drvdata(pdev, tup);
1591 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1592 if (!resource) {
1593 dev_err(&pdev->dev, "No IO memory resource\n");
1594 return -ENODEV;
1595 }
1596
1597 u->mapbase = resource->start;
1598 u->membase = devm_ioremap_resource(&pdev->dev, resource);
1599 if (IS_ERR(u->membase))
1600 return PTR_ERR(u->membase);
1601
1602 tup->uart_clk = devm_clk_get(&pdev->dev, NULL);
1603 if (IS_ERR(tup->uart_clk)) {
1604 dev_err(&pdev->dev, "Couldn't get the clock\n");
1605 return PTR_ERR(tup->uart_clk);
1606 }
1607
1608 tup->rst = devm_reset_control_get_exclusive(&pdev->dev, "serial");
1609 if (IS_ERR(tup->rst)) {
1610 dev_err(&pdev->dev, "Couldn't get the reset\n");
1611 return PTR_ERR(tup->rst);
1612 }
1613
1614 u->iotype = UPIO_MEM32;
1615 ret = platform_get_irq(pdev, 0);
1616 if (ret < 0)
1617 return ret;
1618 u->irq = ret;
1619 u->regshift = 2;
1620 ret = uart_add_one_port(&tegra_uart_driver, u);
1621 if (ret < 0) {
1622 dev_err(&pdev->dev, "Failed to add uart port, err %d\n", ret);
1623 return ret;
1624 }
1625 return ret;
1626}
1627
1628static int tegra_uart_remove(struct platform_device *pdev)
1629{
1630 struct tegra_uart_port *tup = platform_get_drvdata(pdev);
1631 struct uart_port *u = &tup->uport;
1632
1633 uart_remove_one_port(&tegra_uart_driver, u);
1634 return 0;
1635}
1636
1637#ifdef CONFIG_PM_SLEEP
1638static int tegra_uart_suspend(struct device *dev)
1639{
1640 struct tegra_uart_port *tup = dev_get_drvdata(dev);
1641 struct uart_port *u = &tup->uport;
1642
1643 return uart_suspend_port(&tegra_uart_driver, u);
1644}
1645
1646static int tegra_uart_resume(struct device *dev)
1647{
1648 struct tegra_uart_port *tup = dev_get_drvdata(dev);
1649 struct uart_port *u = &tup->uport;
1650
1651 return uart_resume_port(&tegra_uart_driver, u);
1652}
1653#endif
1654
1655static const struct dev_pm_ops tegra_uart_pm_ops = {
1656 SET_SYSTEM_SLEEP_PM_OPS(tegra_uart_suspend, tegra_uart_resume)
1657};
1658
1659static struct platform_driver tegra_uart_platform_driver = {
1660 .probe = tegra_uart_probe,
1661 .remove = tegra_uart_remove,
1662 .driver = {
1663 .name = "serial-tegra",
1664 .of_match_table = tegra_uart_of_match,
1665 .pm = &tegra_uart_pm_ops,
1666 },
1667};
1668
1669static int __init tegra_uart_init(void)
1670{
1671 int ret;
1672 struct device_node *node;
1673 const struct of_device_id *match = NULL;
1674 const struct tegra_uart_chip_data *cdata = NULL;
1675
1676 node = of_find_matching_node(NULL, tegra_uart_of_match);
1677 if (node)
1678 match = of_match_node(tegra_uart_of_match, node);
1679 if (match)
1680 cdata = match->data;
1681 if (cdata)
1682 tegra_uart_driver.nr = cdata->uart_max_port;
1683
1684 ret = uart_register_driver(&tegra_uart_driver);
1685 if (ret < 0) {
1686 pr_err("Could not register %s driver\n",
1687 tegra_uart_driver.driver_name);
1688 return ret;
1689 }
1690
1691 ret = platform_driver_register(&tegra_uart_platform_driver);
1692 if (ret < 0) {
1693 pr_err("Uart platform driver register failed, e = %d\n", ret);
1694 uart_unregister_driver(&tegra_uart_driver);
1695 return ret;
1696 }
1697 return 0;
1698}
1699
1700static void __exit tegra_uart_exit(void)
1701{
1702 pr_info("Unloading tegra uart driver\n");
1703 platform_driver_unregister(&tegra_uart_platform_driver);
1704 uart_unregister_driver(&tegra_uart_driver);
1705}
1706
1707module_init(tegra_uart_init);
1708module_exit(tegra_uart_exit);
1709
1710MODULE_ALIAS("platform:serial-tegra");
1711MODULE_DESCRIPTION("High speed UART driver for tegra chipset");
1712MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
1713MODULE_LICENSE("GPL v2");
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * serial_tegra.c
4 *
5 * High-speed serial driver for NVIDIA Tegra SoCs
6 *
7 * Copyright (c) 2012-2013, NVIDIA CORPORATION. All rights reserved.
8 *
9 * Author: Laxman Dewangan <ldewangan@nvidia.com>
10 */
11
12#include <linux/clk.h>
13#include <linux/debugfs.h>
14#include <linux/delay.h>
15#include <linux/dmaengine.h>
16#include <linux/dma-mapping.h>
17#include <linux/dmapool.h>
18#include <linux/err.h>
19#include <linux/io.h>
20#include <linux/irq.h>
21#include <linux/module.h>
22#include <linux/of.h>
23#include <linux/of_device.h>
24#include <linux/pagemap.h>
25#include <linux/platform_device.h>
26#include <linux/reset.h>
27#include <linux/serial.h>
28#include <linux/serial_8250.h>
29#include <linux/serial_core.h>
30#include <linux/serial_reg.h>
31#include <linux/slab.h>
32#include <linux/string.h>
33#include <linux/termios.h>
34#include <linux/tty.h>
35#include <linux/tty_flip.h>
36
37#define TEGRA_UART_TYPE "TEGRA_UART"
38#define TX_EMPTY_STATUS (UART_LSR_TEMT | UART_LSR_THRE)
39#define BYTES_TO_ALIGN(x) ((unsigned long)(x) & 0x3)
40
41#define TEGRA_UART_RX_DMA_BUFFER_SIZE 4096
42#define TEGRA_UART_LSR_TXFIFO_FULL 0x100
43#define TEGRA_UART_IER_EORD 0x20
44#define TEGRA_UART_MCR_RTS_EN 0x40
45#define TEGRA_UART_MCR_CTS_EN 0x20
46#define TEGRA_UART_LSR_ANY (UART_LSR_OE | UART_LSR_BI | \
47 UART_LSR_PE | UART_LSR_FE)
48#define TEGRA_UART_IRDA_CSR 0x08
49#define TEGRA_UART_SIR_ENABLED 0x80
50
51#define TEGRA_UART_TX_PIO 1
52#define TEGRA_UART_TX_DMA 2
53#define TEGRA_UART_MIN_DMA 16
54#define TEGRA_UART_FIFO_SIZE 32
55
56/*
57 * Tx fifo trigger level setting in tegra uart is in
58 * reverse way then conventional uart.
59 */
60#define TEGRA_UART_TX_TRIG_16B 0x00
61#define TEGRA_UART_TX_TRIG_8B 0x10
62#define TEGRA_UART_TX_TRIG_4B 0x20
63#define TEGRA_UART_TX_TRIG_1B 0x30
64
65#define TEGRA_UART_MAXIMUM 5
66
67/* Default UART setting when started: 115200 no parity, stop, 8 data bits */
68#define TEGRA_UART_DEFAULT_BAUD 115200
69#define TEGRA_UART_DEFAULT_LSR UART_LCR_WLEN8
70
71/* Tx transfer mode */
72#define TEGRA_TX_PIO 1
73#define TEGRA_TX_DMA 2
74
75/**
76 * tegra_uart_chip_data: SOC specific data.
77 *
78 * @tx_fifo_full_status: Status flag available for checking tx fifo full.
79 * @allow_txfifo_reset_fifo_mode: allow_tx fifo reset with fifo mode or not.
80 * Tegra30 does not allow this.
81 * @support_clk_src_div: Clock source support the clock divider.
82 */
83struct tegra_uart_chip_data {
84 bool tx_fifo_full_status;
85 bool allow_txfifo_reset_fifo_mode;
86 bool support_clk_src_div;
87};
88
89struct tegra_uart_port {
90 struct uart_port uport;
91 const struct tegra_uart_chip_data *cdata;
92
93 struct clk *uart_clk;
94 struct reset_control *rst;
95 unsigned int current_baud;
96
97 /* Register shadow */
98 unsigned long fcr_shadow;
99 unsigned long mcr_shadow;
100 unsigned long lcr_shadow;
101 unsigned long ier_shadow;
102 bool rts_active;
103
104 int tx_in_progress;
105 unsigned int tx_bytes;
106
107 bool enable_modem_interrupt;
108
109 bool rx_timeout;
110 int rx_in_progress;
111 int symb_bit;
112
113 struct dma_chan *rx_dma_chan;
114 struct dma_chan *tx_dma_chan;
115 dma_addr_t rx_dma_buf_phys;
116 dma_addr_t tx_dma_buf_phys;
117 unsigned char *rx_dma_buf_virt;
118 unsigned char *tx_dma_buf_virt;
119 struct dma_async_tx_descriptor *tx_dma_desc;
120 struct dma_async_tx_descriptor *rx_dma_desc;
121 dma_cookie_t tx_cookie;
122 dma_cookie_t rx_cookie;
123 unsigned int tx_bytes_requested;
124 unsigned int rx_bytes_requested;
125};
126
127static void tegra_uart_start_next_tx(struct tegra_uart_port *tup);
128static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup);
129
130static inline unsigned long tegra_uart_read(struct tegra_uart_port *tup,
131 unsigned long reg)
132{
133 return readl(tup->uport.membase + (reg << tup->uport.regshift));
134}
135
136static inline void tegra_uart_write(struct tegra_uart_port *tup, unsigned val,
137 unsigned long reg)
138{
139 writel(val, tup->uport.membase + (reg << tup->uport.regshift));
140}
141
142static inline struct tegra_uart_port *to_tegra_uport(struct uart_port *u)
143{
144 return container_of(u, struct tegra_uart_port, uport);
145}
146
147static unsigned int tegra_uart_get_mctrl(struct uart_port *u)
148{
149 struct tegra_uart_port *tup = to_tegra_uport(u);
150
151 /*
152 * RI - Ring detector is active
153 * CD/DCD/CAR - Carrier detect is always active. For some reason
154 * linux has different names for carrier detect.
155 * DSR - Data Set ready is active as the hardware doesn't support it.
156 * Don't know if the linux support this yet?
157 * CTS - Clear to send. Always set to active, as the hardware handles
158 * CTS automatically.
159 */
160 if (tup->enable_modem_interrupt)
161 return TIOCM_RI | TIOCM_CD | TIOCM_DSR | TIOCM_CTS;
162 return TIOCM_CTS;
163}
164
165static void set_rts(struct tegra_uart_port *tup, bool active)
166{
167 unsigned long mcr;
168
169 mcr = tup->mcr_shadow;
170 if (active)
171 mcr |= TEGRA_UART_MCR_RTS_EN;
172 else
173 mcr &= ~TEGRA_UART_MCR_RTS_EN;
174 if (mcr != tup->mcr_shadow) {
175 tegra_uart_write(tup, mcr, UART_MCR);
176 tup->mcr_shadow = mcr;
177 }
178}
179
180static void set_dtr(struct tegra_uart_port *tup, bool active)
181{
182 unsigned long mcr;
183
184 mcr = tup->mcr_shadow;
185 if (active)
186 mcr |= UART_MCR_DTR;
187 else
188 mcr &= ~UART_MCR_DTR;
189 if (mcr != tup->mcr_shadow) {
190 tegra_uart_write(tup, mcr, UART_MCR);
191 tup->mcr_shadow = mcr;
192 }
193}
194
195static void tegra_uart_set_mctrl(struct uart_port *u, unsigned int mctrl)
196{
197 struct tegra_uart_port *tup = to_tegra_uport(u);
198 int dtr_enable;
199
200 tup->rts_active = !!(mctrl & TIOCM_RTS);
201 set_rts(tup, tup->rts_active);
202
203 dtr_enable = !!(mctrl & TIOCM_DTR);
204 set_dtr(tup, dtr_enable);
205}
206
207static void tegra_uart_break_ctl(struct uart_port *u, int break_ctl)
208{
209 struct tegra_uart_port *tup = to_tegra_uport(u);
210 unsigned long lcr;
211
212 lcr = tup->lcr_shadow;
213 if (break_ctl)
214 lcr |= UART_LCR_SBC;
215 else
216 lcr &= ~UART_LCR_SBC;
217 tegra_uart_write(tup, lcr, UART_LCR);
218 tup->lcr_shadow = lcr;
219}
220
221/**
222 * tegra_uart_wait_cycle_time: Wait for N UART clock periods
223 *
224 * @tup: Tegra serial port data structure.
225 * @cycles: Number of clock periods to wait.
226 *
227 * Tegra UARTs are clocked at 16X the baud/bit rate and hence the UART
228 * clock speed is 16X the current baud rate.
229 */
230static void tegra_uart_wait_cycle_time(struct tegra_uart_port *tup,
231 unsigned int cycles)
232{
233 if (tup->current_baud)
234 udelay(DIV_ROUND_UP(cycles * 1000000, tup->current_baud * 16));
235}
236
237/* Wait for a symbol-time. */
238static void tegra_uart_wait_sym_time(struct tegra_uart_port *tup,
239 unsigned int syms)
240{
241 if (tup->current_baud)
242 udelay(DIV_ROUND_UP(syms * tup->symb_bit * 1000000,
243 tup->current_baud));
244}
245
246static void tegra_uart_fifo_reset(struct tegra_uart_port *tup, u8 fcr_bits)
247{
248 unsigned long fcr = tup->fcr_shadow;
249
250 if (tup->cdata->allow_txfifo_reset_fifo_mode) {
251 fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
252 tegra_uart_write(tup, fcr, UART_FCR);
253 } else {
254 fcr &= ~UART_FCR_ENABLE_FIFO;
255 tegra_uart_write(tup, fcr, UART_FCR);
256 udelay(60);
257 fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
258 tegra_uart_write(tup, fcr, UART_FCR);
259 fcr |= UART_FCR_ENABLE_FIFO;
260 tegra_uart_write(tup, fcr, UART_FCR);
261 }
262
263 /* Dummy read to ensure the write is posted */
264 tegra_uart_read(tup, UART_SCR);
265
266 /*
267 * For all tegra devices (up to t210), there is a hardware issue that
268 * requires software to wait for 32 UART clock periods for the flush
269 * to propagate, otherwise data could be lost.
270 */
271 tegra_uart_wait_cycle_time(tup, 32);
272}
273
274static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud)
275{
276 unsigned long rate;
277 unsigned int divisor;
278 unsigned long lcr;
279 int ret;
280
281 if (tup->current_baud == baud)
282 return 0;
283
284 if (tup->cdata->support_clk_src_div) {
285 rate = baud * 16;
286 ret = clk_set_rate(tup->uart_clk, rate);
287 if (ret < 0) {
288 dev_err(tup->uport.dev,
289 "clk_set_rate() failed for rate %lu\n", rate);
290 return ret;
291 }
292 divisor = 1;
293 } else {
294 rate = clk_get_rate(tup->uart_clk);
295 divisor = DIV_ROUND_CLOSEST(rate, baud * 16);
296 }
297
298 lcr = tup->lcr_shadow;
299 lcr |= UART_LCR_DLAB;
300 tegra_uart_write(tup, lcr, UART_LCR);
301
302 tegra_uart_write(tup, divisor & 0xFF, UART_TX);
303 tegra_uart_write(tup, ((divisor >> 8) & 0xFF), UART_IER);
304
305 lcr &= ~UART_LCR_DLAB;
306 tegra_uart_write(tup, lcr, UART_LCR);
307
308 /* Dummy read to ensure the write is posted */
309 tegra_uart_read(tup, UART_SCR);
310
311 tup->current_baud = baud;
312
313 /* wait two character intervals at new rate */
314 tegra_uart_wait_sym_time(tup, 2);
315 return 0;
316}
317
318static char tegra_uart_decode_rx_error(struct tegra_uart_port *tup,
319 unsigned long lsr)
320{
321 char flag = TTY_NORMAL;
322
323 if (unlikely(lsr & TEGRA_UART_LSR_ANY)) {
324 if (lsr & UART_LSR_OE) {
325 /* Overrrun error */
326 flag = TTY_OVERRUN;
327 tup->uport.icount.overrun++;
328 dev_err(tup->uport.dev, "Got overrun errors\n");
329 } else if (lsr & UART_LSR_PE) {
330 /* Parity error */
331 flag = TTY_PARITY;
332 tup->uport.icount.parity++;
333 dev_err(tup->uport.dev, "Got Parity errors\n");
334 } else if (lsr & UART_LSR_FE) {
335 flag = TTY_FRAME;
336 tup->uport.icount.frame++;
337 dev_err(tup->uport.dev, "Got frame errors\n");
338 } else if (lsr & UART_LSR_BI) {
339 dev_err(tup->uport.dev, "Got Break\n");
340 tup->uport.icount.brk++;
341 /* If FIFO read error without any data, reset Rx FIFO */
342 if (!(lsr & UART_LSR_DR) && (lsr & UART_LSR_FIFOE))
343 tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_RCVR);
344 }
345 }
346 return flag;
347}
348
349static int tegra_uart_request_port(struct uart_port *u)
350{
351 return 0;
352}
353
354static void tegra_uart_release_port(struct uart_port *u)
355{
356 /* Nothing to do here */
357}
358
359static void tegra_uart_fill_tx_fifo(struct tegra_uart_port *tup, int max_bytes)
360{
361 struct circ_buf *xmit = &tup->uport.state->xmit;
362 int i;
363
364 for (i = 0; i < max_bytes; i++) {
365 BUG_ON(uart_circ_empty(xmit));
366 if (tup->cdata->tx_fifo_full_status) {
367 unsigned long lsr = tegra_uart_read(tup, UART_LSR);
368 if ((lsr & TEGRA_UART_LSR_TXFIFO_FULL))
369 break;
370 }
371 tegra_uart_write(tup, xmit->buf[xmit->tail], UART_TX);
372 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
373 tup->uport.icount.tx++;
374 }
375}
376
377static void tegra_uart_start_pio_tx(struct tegra_uart_port *tup,
378 unsigned int bytes)
379{
380 if (bytes > TEGRA_UART_MIN_DMA)
381 bytes = TEGRA_UART_MIN_DMA;
382
383 tup->tx_in_progress = TEGRA_UART_TX_PIO;
384 tup->tx_bytes = bytes;
385 tup->ier_shadow |= UART_IER_THRI;
386 tegra_uart_write(tup, tup->ier_shadow, UART_IER);
387}
388
389static void tegra_uart_tx_dma_complete(void *args)
390{
391 struct tegra_uart_port *tup = args;
392 struct circ_buf *xmit = &tup->uport.state->xmit;
393 struct dma_tx_state state;
394 unsigned long flags;
395 unsigned int count;
396
397 dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state);
398 count = tup->tx_bytes_requested - state.residue;
399 async_tx_ack(tup->tx_dma_desc);
400 spin_lock_irqsave(&tup->uport.lock, flags);
401 xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
402 tup->tx_in_progress = 0;
403 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
404 uart_write_wakeup(&tup->uport);
405 tegra_uart_start_next_tx(tup);
406 spin_unlock_irqrestore(&tup->uport.lock, flags);
407}
408
409static int tegra_uart_start_tx_dma(struct tegra_uart_port *tup,
410 unsigned long count)
411{
412 struct circ_buf *xmit = &tup->uport.state->xmit;
413 dma_addr_t tx_phys_addr;
414
415 dma_sync_single_for_device(tup->uport.dev, tup->tx_dma_buf_phys,
416 UART_XMIT_SIZE, DMA_TO_DEVICE);
417
418 tup->tx_bytes = count & ~(0xF);
419 tx_phys_addr = tup->tx_dma_buf_phys + xmit->tail;
420 tup->tx_dma_desc = dmaengine_prep_slave_single(tup->tx_dma_chan,
421 tx_phys_addr, tup->tx_bytes, DMA_MEM_TO_DEV,
422 DMA_PREP_INTERRUPT);
423 if (!tup->tx_dma_desc) {
424 dev_err(tup->uport.dev, "Not able to get desc for Tx\n");
425 return -EIO;
426 }
427
428 tup->tx_dma_desc->callback = tegra_uart_tx_dma_complete;
429 tup->tx_dma_desc->callback_param = tup;
430 tup->tx_in_progress = TEGRA_UART_TX_DMA;
431 tup->tx_bytes_requested = tup->tx_bytes;
432 tup->tx_cookie = dmaengine_submit(tup->tx_dma_desc);
433 dma_async_issue_pending(tup->tx_dma_chan);
434 return 0;
435}
436
437static void tegra_uart_start_next_tx(struct tegra_uart_port *tup)
438{
439 unsigned long tail;
440 unsigned long count;
441 struct circ_buf *xmit = &tup->uport.state->xmit;
442
443 tail = (unsigned long)&xmit->buf[xmit->tail];
444 count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
445 if (!count)
446 return;
447
448 if (count < TEGRA_UART_MIN_DMA)
449 tegra_uart_start_pio_tx(tup, count);
450 else if (BYTES_TO_ALIGN(tail) > 0)
451 tegra_uart_start_pio_tx(tup, BYTES_TO_ALIGN(tail));
452 else
453 tegra_uart_start_tx_dma(tup, count);
454}
455
456/* Called by serial core driver with u->lock taken. */
457static void tegra_uart_start_tx(struct uart_port *u)
458{
459 struct tegra_uart_port *tup = to_tegra_uport(u);
460 struct circ_buf *xmit = &u->state->xmit;
461
462 if (!uart_circ_empty(xmit) && !tup->tx_in_progress)
463 tegra_uart_start_next_tx(tup);
464}
465
466static unsigned int tegra_uart_tx_empty(struct uart_port *u)
467{
468 struct tegra_uart_port *tup = to_tegra_uport(u);
469 unsigned int ret = 0;
470 unsigned long flags;
471
472 spin_lock_irqsave(&u->lock, flags);
473 if (!tup->tx_in_progress) {
474 unsigned long lsr = tegra_uart_read(tup, UART_LSR);
475 if ((lsr & TX_EMPTY_STATUS) == TX_EMPTY_STATUS)
476 ret = TIOCSER_TEMT;
477 }
478 spin_unlock_irqrestore(&u->lock, flags);
479 return ret;
480}
481
482static void tegra_uart_stop_tx(struct uart_port *u)
483{
484 struct tegra_uart_port *tup = to_tegra_uport(u);
485 struct circ_buf *xmit = &tup->uport.state->xmit;
486 struct dma_tx_state state;
487 unsigned int count;
488
489 if (tup->tx_in_progress != TEGRA_UART_TX_DMA)
490 return;
491
492 dmaengine_terminate_all(tup->tx_dma_chan);
493 dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state);
494 count = tup->tx_bytes_requested - state.residue;
495 async_tx_ack(tup->tx_dma_desc);
496 xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
497 tup->tx_in_progress = 0;
498}
499
500static void tegra_uart_handle_tx_pio(struct tegra_uart_port *tup)
501{
502 struct circ_buf *xmit = &tup->uport.state->xmit;
503
504 tegra_uart_fill_tx_fifo(tup, tup->tx_bytes);
505 tup->tx_in_progress = 0;
506 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
507 uart_write_wakeup(&tup->uport);
508 tegra_uart_start_next_tx(tup);
509}
510
511static void tegra_uart_handle_rx_pio(struct tegra_uart_port *tup,
512 struct tty_port *tty)
513{
514 do {
515 char flag = TTY_NORMAL;
516 unsigned long lsr = 0;
517 unsigned char ch;
518
519 lsr = tegra_uart_read(tup, UART_LSR);
520 if (!(lsr & UART_LSR_DR))
521 break;
522
523 flag = tegra_uart_decode_rx_error(tup, lsr);
524 ch = (unsigned char) tegra_uart_read(tup, UART_RX);
525 tup->uport.icount.rx++;
526
527 if (!uart_handle_sysrq_char(&tup->uport, ch) && tty)
528 tty_insert_flip_char(tty, ch, flag);
529 } while (1);
530}
531
532static void tegra_uart_copy_rx_to_tty(struct tegra_uart_port *tup,
533 struct tty_port *tty,
534 unsigned int count)
535{
536 int copied;
537
538 /* If count is zero, then there is no data to be copied */
539 if (!count)
540 return;
541
542 tup->uport.icount.rx += count;
543 if (!tty) {
544 dev_err(tup->uport.dev, "No tty port\n");
545 return;
546 }
547 dma_sync_single_for_cpu(tup->uport.dev, tup->rx_dma_buf_phys,
548 TEGRA_UART_RX_DMA_BUFFER_SIZE, DMA_FROM_DEVICE);
549 copied = tty_insert_flip_string(tty,
550 ((unsigned char *)(tup->rx_dma_buf_virt)), count);
551 if (copied != count) {
552 WARN_ON(1);
553 dev_err(tup->uport.dev, "RxData copy to tty layer failed\n");
554 }
555 dma_sync_single_for_device(tup->uport.dev, tup->rx_dma_buf_phys,
556 TEGRA_UART_RX_DMA_BUFFER_SIZE, DMA_TO_DEVICE);
557}
558
559static void tegra_uart_rx_buffer_push(struct tegra_uart_port *tup,
560 unsigned int residue)
561{
562 struct tty_port *port = &tup->uport.state->port;
563 struct tty_struct *tty = tty_port_tty_get(port);
564 unsigned int count;
565
566 async_tx_ack(tup->rx_dma_desc);
567 count = tup->rx_bytes_requested - residue;
568
569 /* If we are here, DMA is stopped */
570 tegra_uart_copy_rx_to_tty(tup, port, count);
571
572 tegra_uart_handle_rx_pio(tup, port);
573 if (tty) {
574 tty_flip_buffer_push(port);
575 tty_kref_put(tty);
576 }
577}
578
579static void tegra_uart_rx_dma_complete(void *args)
580{
581 struct tegra_uart_port *tup = args;
582 struct uart_port *u = &tup->uport;
583 unsigned long flags;
584 struct dma_tx_state state;
585 enum dma_status status;
586
587 spin_lock_irqsave(&u->lock, flags);
588
589 status = dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
590
591 if (status == DMA_IN_PROGRESS) {
592 dev_dbg(tup->uport.dev, "RX DMA is in progress\n");
593 goto done;
594 }
595
596 /* Deactivate flow control to stop sender */
597 if (tup->rts_active)
598 set_rts(tup, false);
599
600 tegra_uart_rx_buffer_push(tup, 0);
601 tegra_uart_start_rx_dma(tup);
602
603 /* Activate flow control to start transfer */
604 if (tup->rts_active)
605 set_rts(tup, true);
606
607done:
608 spin_unlock_irqrestore(&u->lock, flags);
609}
610
611static void tegra_uart_handle_rx_dma(struct tegra_uart_port *tup)
612{
613 struct dma_tx_state state;
614
615 /* Deactivate flow control to stop sender */
616 if (tup->rts_active)
617 set_rts(tup, false);
618
619 dmaengine_terminate_all(tup->rx_dma_chan);
620 dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
621 tegra_uart_rx_buffer_push(tup, state.residue);
622 tegra_uart_start_rx_dma(tup);
623
624 if (tup->rts_active)
625 set_rts(tup, true);
626}
627
628static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup)
629{
630 unsigned int count = TEGRA_UART_RX_DMA_BUFFER_SIZE;
631
632 tup->rx_dma_desc = dmaengine_prep_slave_single(tup->rx_dma_chan,
633 tup->rx_dma_buf_phys, count, DMA_DEV_TO_MEM,
634 DMA_PREP_INTERRUPT);
635 if (!tup->rx_dma_desc) {
636 dev_err(tup->uport.dev, "Not able to get desc for Rx\n");
637 return -EIO;
638 }
639
640 tup->rx_dma_desc->callback = tegra_uart_rx_dma_complete;
641 tup->rx_dma_desc->callback_param = tup;
642 dma_sync_single_for_device(tup->uport.dev, tup->rx_dma_buf_phys,
643 count, DMA_TO_DEVICE);
644 tup->rx_bytes_requested = count;
645 tup->rx_cookie = dmaengine_submit(tup->rx_dma_desc);
646 dma_async_issue_pending(tup->rx_dma_chan);
647 return 0;
648}
649
650static void tegra_uart_handle_modem_signal_change(struct uart_port *u)
651{
652 struct tegra_uart_port *tup = to_tegra_uport(u);
653 unsigned long msr;
654
655 msr = tegra_uart_read(tup, UART_MSR);
656 if (!(msr & UART_MSR_ANY_DELTA))
657 return;
658
659 if (msr & UART_MSR_TERI)
660 tup->uport.icount.rng++;
661 if (msr & UART_MSR_DDSR)
662 tup->uport.icount.dsr++;
663 /* We may only get DDCD when HW init and reset */
664 if (msr & UART_MSR_DDCD)
665 uart_handle_dcd_change(&tup->uport, msr & UART_MSR_DCD);
666 /* Will start/stop_tx accordingly */
667 if (msr & UART_MSR_DCTS)
668 uart_handle_cts_change(&tup->uport, msr & UART_MSR_CTS);
669}
670
671static irqreturn_t tegra_uart_isr(int irq, void *data)
672{
673 struct tegra_uart_port *tup = data;
674 struct uart_port *u = &tup->uport;
675 unsigned long iir;
676 unsigned long ier;
677 bool is_rx_int = false;
678 unsigned long flags;
679
680 spin_lock_irqsave(&u->lock, flags);
681 while (1) {
682 iir = tegra_uart_read(tup, UART_IIR);
683 if (iir & UART_IIR_NO_INT) {
684 if (is_rx_int) {
685 tegra_uart_handle_rx_dma(tup);
686 if (tup->rx_in_progress) {
687 ier = tup->ier_shadow;
688 ier |= (UART_IER_RLSI | UART_IER_RTOIE |
689 TEGRA_UART_IER_EORD);
690 tup->ier_shadow = ier;
691 tegra_uart_write(tup, ier, UART_IER);
692 }
693 }
694 spin_unlock_irqrestore(&u->lock, flags);
695 return IRQ_HANDLED;
696 }
697
698 switch ((iir >> 1) & 0x7) {
699 case 0: /* Modem signal change interrupt */
700 tegra_uart_handle_modem_signal_change(u);
701 break;
702
703 case 1: /* Transmit interrupt only triggered when using PIO */
704 tup->ier_shadow &= ~UART_IER_THRI;
705 tegra_uart_write(tup, tup->ier_shadow, UART_IER);
706 tegra_uart_handle_tx_pio(tup);
707 break;
708
709 case 4: /* End of data */
710 case 6: /* Rx timeout */
711 case 2: /* Receive */
712 if (!is_rx_int) {
713 is_rx_int = true;
714 /* Disable Rx interrupts */
715 ier = tup->ier_shadow;
716 ier |= UART_IER_RDI;
717 tegra_uart_write(tup, ier, UART_IER);
718 ier &= ~(UART_IER_RDI | UART_IER_RLSI |
719 UART_IER_RTOIE | TEGRA_UART_IER_EORD);
720 tup->ier_shadow = ier;
721 tegra_uart_write(tup, ier, UART_IER);
722 }
723 break;
724
725 case 3: /* Receive error */
726 tegra_uart_decode_rx_error(tup,
727 tegra_uart_read(tup, UART_LSR));
728 break;
729
730 case 5: /* break nothing to handle */
731 case 7: /* break nothing to handle */
732 break;
733 }
734 }
735}
736
737static void tegra_uart_stop_rx(struct uart_port *u)
738{
739 struct tegra_uart_port *tup = to_tegra_uport(u);
740 struct dma_tx_state state;
741 unsigned long ier;
742
743 if (tup->rts_active)
744 set_rts(tup, false);
745
746 if (!tup->rx_in_progress)
747 return;
748
749 tegra_uart_wait_sym_time(tup, 1); /* wait a character interval */
750
751 ier = tup->ier_shadow;
752 ier &= ~(UART_IER_RDI | UART_IER_RLSI | UART_IER_RTOIE |
753 TEGRA_UART_IER_EORD);
754 tup->ier_shadow = ier;
755 tegra_uart_write(tup, ier, UART_IER);
756 tup->rx_in_progress = 0;
757 dmaengine_terminate_all(tup->rx_dma_chan);
758 dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
759 tegra_uart_rx_buffer_push(tup, state.residue);
760}
761
762static void tegra_uart_hw_deinit(struct tegra_uart_port *tup)
763{
764 unsigned long flags;
765 unsigned long char_time = DIV_ROUND_UP(10000000, tup->current_baud);
766 unsigned long fifo_empty_time = tup->uport.fifosize * char_time;
767 unsigned long wait_time;
768 unsigned long lsr;
769 unsigned long msr;
770 unsigned long mcr;
771
772 /* Disable interrupts */
773 tegra_uart_write(tup, 0, UART_IER);
774
775 lsr = tegra_uart_read(tup, UART_LSR);
776 if ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) {
777 msr = tegra_uart_read(tup, UART_MSR);
778 mcr = tegra_uart_read(tup, UART_MCR);
779 if ((mcr & TEGRA_UART_MCR_CTS_EN) && (msr & UART_MSR_CTS))
780 dev_err(tup->uport.dev,
781 "Tx Fifo not empty, CTS disabled, waiting\n");
782
783 /* Wait for Tx fifo to be empty */
784 while ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) {
785 wait_time = min(fifo_empty_time, 100lu);
786 udelay(wait_time);
787 fifo_empty_time -= wait_time;
788 if (!fifo_empty_time) {
789 msr = tegra_uart_read(tup, UART_MSR);
790 mcr = tegra_uart_read(tup, UART_MCR);
791 if ((mcr & TEGRA_UART_MCR_CTS_EN) &&
792 (msr & UART_MSR_CTS))
793 dev_err(tup->uport.dev,
794 "Slave not ready\n");
795 break;
796 }
797 lsr = tegra_uart_read(tup, UART_LSR);
798 }
799 }
800
801 spin_lock_irqsave(&tup->uport.lock, flags);
802 /* Reset the Rx and Tx FIFOs */
803 tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_XMIT | UART_FCR_CLEAR_RCVR);
804 tup->current_baud = 0;
805 spin_unlock_irqrestore(&tup->uport.lock, flags);
806
807 clk_disable_unprepare(tup->uart_clk);
808}
809
810static int tegra_uart_hw_init(struct tegra_uart_port *tup)
811{
812 int ret;
813
814 tup->fcr_shadow = 0;
815 tup->mcr_shadow = 0;
816 tup->lcr_shadow = 0;
817 tup->ier_shadow = 0;
818 tup->current_baud = 0;
819
820 clk_prepare_enable(tup->uart_clk);
821
822 /* Reset the UART controller to clear all previous status.*/
823 reset_control_assert(tup->rst);
824 udelay(10);
825 reset_control_deassert(tup->rst);
826
827 tup->rx_in_progress = 0;
828 tup->tx_in_progress = 0;
829
830 /*
831 * Set the trigger level
832 *
833 * For PIO mode:
834 *
835 * For receive, this will interrupt the CPU after that many number of
836 * bytes are received, for the remaining bytes the receive timeout
837 * interrupt is received. Rx high watermark is set to 4.
838 *
839 * For transmit, if the trasnmit interrupt is enabled, this will
840 * interrupt the CPU when the number of entries in the FIFO reaches the
841 * low watermark. Tx low watermark is set to 16 bytes.
842 *
843 * For DMA mode:
844 *
845 * Set the Tx trigger to 16. This should match the DMA burst size that
846 * programmed in the DMA registers.
847 */
848 tup->fcr_shadow = UART_FCR_ENABLE_FIFO;
849 tup->fcr_shadow |= UART_FCR_R_TRIG_01;
850 tup->fcr_shadow |= TEGRA_UART_TX_TRIG_16B;
851 tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
852
853 /* Dummy read to ensure the write is posted */
854 tegra_uart_read(tup, UART_SCR);
855
856 /*
857 * For all tegra devices (up to t210), there is a hardware issue that
858 * requires software to wait for 3 UART clock periods after enabling
859 * the TX fifo, otherwise data could be lost.
860 */
861 tegra_uart_wait_cycle_time(tup, 3);
862
863 /*
864 * Initialize the UART with default configuration
865 * (115200, N, 8, 1) so that the receive DMA buffer may be
866 * enqueued
867 */
868 tup->lcr_shadow = TEGRA_UART_DEFAULT_LSR;
869 tegra_set_baudrate(tup, TEGRA_UART_DEFAULT_BAUD);
870 tup->fcr_shadow |= UART_FCR_DMA_SELECT;
871 tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
872
873 ret = tegra_uart_start_rx_dma(tup);
874 if (ret < 0) {
875 dev_err(tup->uport.dev, "Not able to start Rx DMA\n");
876 return ret;
877 }
878 tup->rx_in_progress = 1;
879
880 /*
881 * Enable IE_RXS for the receive status interrupts like line errros.
882 * Enable IE_RX_TIMEOUT to get the bytes which cannot be DMA'd.
883 *
884 * If using DMA mode, enable EORD instead of receive interrupt which
885 * will interrupt after the UART is done with the receive instead of
886 * the interrupt when the FIFO "threshold" is reached.
887 *
888 * EORD is different interrupt than RX_TIMEOUT - RX_TIMEOUT occurs when
889 * the DATA is sitting in the FIFO and couldn't be transferred to the
890 * DMA as the DMA size alignment(4 bytes) is not met. EORD will be
891 * triggered when there is a pause of the incomming data stream for 4
892 * characters long.
893 *
894 * For pauses in the data which is not aligned to 4 bytes, we get
895 * both the EORD as well as RX_TIMEOUT - SW sees RX_TIMEOUT first
896 * then the EORD.
897 */
898 tup->ier_shadow = UART_IER_RLSI | UART_IER_RTOIE | TEGRA_UART_IER_EORD;
899 tegra_uart_write(tup, tup->ier_shadow, UART_IER);
900 return 0;
901}
902
903static void tegra_uart_dma_channel_free(struct tegra_uart_port *tup,
904 bool dma_to_memory)
905{
906 if (dma_to_memory) {
907 dmaengine_terminate_all(tup->rx_dma_chan);
908 dma_release_channel(tup->rx_dma_chan);
909 dma_free_coherent(tup->uport.dev, TEGRA_UART_RX_DMA_BUFFER_SIZE,
910 tup->rx_dma_buf_virt, tup->rx_dma_buf_phys);
911 tup->rx_dma_chan = NULL;
912 tup->rx_dma_buf_phys = 0;
913 tup->rx_dma_buf_virt = NULL;
914 } else {
915 dmaengine_terminate_all(tup->tx_dma_chan);
916 dma_release_channel(tup->tx_dma_chan);
917 dma_unmap_single(tup->uport.dev, tup->tx_dma_buf_phys,
918 UART_XMIT_SIZE, DMA_TO_DEVICE);
919 tup->tx_dma_chan = NULL;
920 tup->tx_dma_buf_phys = 0;
921 tup->tx_dma_buf_virt = NULL;
922 }
923}
924
925static int tegra_uart_dma_channel_allocate(struct tegra_uart_port *tup,
926 bool dma_to_memory)
927{
928 struct dma_chan *dma_chan;
929 unsigned char *dma_buf;
930 dma_addr_t dma_phys;
931 int ret;
932 struct dma_slave_config dma_sconfig;
933
934 dma_chan = dma_request_slave_channel_reason(tup->uport.dev,
935 dma_to_memory ? "rx" : "tx");
936 if (IS_ERR(dma_chan)) {
937 ret = PTR_ERR(dma_chan);
938 dev_err(tup->uport.dev,
939 "DMA channel alloc failed: %d\n", ret);
940 return ret;
941 }
942
943 if (dma_to_memory) {
944 dma_buf = dma_alloc_coherent(tup->uport.dev,
945 TEGRA_UART_RX_DMA_BUFFER_SIZE,
946 &dma_phys, GFP_KERNEL);
947 if (!dma_buf) {
948 dev_err(tup->uport.dev,
949 "Not able to allocate the dma buffer\n");
950 dma_release_channel(dma_chan);
951 return -ENOMEM;
952 }
953 dma_sconfig.src_addr = tup->uport.mapbase;
954 dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
955 dma_sconfig.src_maxburst = 4;
956 tup->rx_dma_chan = dma_chan;
957 tup->rx_dma_buf_virt = dma_buf;
958 tup->rx_dma_buf_phys = dma_phys;
959 } else {
960 dma_phys = dma_map_single(tup->uport.dev,
961 tup->uport.state->xmit.buf, UART_XMIT_SIZE,
962 DMA_TO_DEVICE);
963 if (dma_mapping_error(tup->uport.dev, dma_phys)) {
964 dev_err(tup->uport.dev, "dma_map_single tx failed\n");
965 dma_release_channel(dma_chan);
966 return -ENOMEM;
967 }
968 dma_buf = tup->uport.state->xmit.buf;
969 dma_sconfig.dst_addr = tup->uport.mapbase;
970 dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
971 dma_sconfig.dst_maxburst = 16;
972 tup->tx_dma_chan = dma_chan;
973 tup->tx_dma_buf_virt = dma_buf;
974 tup->tx_dma_buf_phys = dma_phys;
975 }
976
977 ret = dmaengine_slave_config(dma_chan, &dma_sconfig);
978 if (ret < 0) {
979 dev_err(tup->uport.dev,
980 "Dma slave config failed, err = %d\n", ret);
981 tegra_uart_dma_channel_free(tup, dma_to_memory);
982 return ret;
983 }
984
985 return 0;
986}
987
988static int tegra_uart_startup(struct uart_port *u)
989{
990 struct tegra_uart_port *tup = to_tegra_uport(u);
991 int ret;
992
993 ret = tegra_uart_dma_channel_allocate(tup, false);
994 if (ret < 0) {
995 dev_err(u->dev, "Tx Dma allocation failed, err = %d\n", ret);
996 return ret;
997 }
998
999 ret = tegra_uart_dma_channel_allocate(tup, true);
1000 if (ret < 0) {
1001 dev_err(u->dev, "Rx Dma allocation failed, err = %d\n", ret);
1002 goto fail_rx_dma;
1003 }
1004
1005 ret = tegra_uart_hw_init(tup);
1006 if (ret < 0) {
1007 dev_err(u->dev, "Uart HW init failed, err = %d\n", ret);
1008 goto fail_hw_init;
1009 }
1010
1011 ret = request_irq(u->irq, tegra_uart_isr, 0,
1012 dev_name(u->dev), tup);
1013 if (ret < 0) {
1014 dev_err(u->dev, "Failed to register ISR for IRQ %d\n", u->irq);
1015 goto fail_hw_init;
1016 }
1017 return 0;
1018
1019fail_hw_init:
1020 tegra_uart_dma_channel_free(tup, true);
1021fail_rx_dma:
1022 tegra_uart_dma_channel_free(tup, false);
1023 return ret;
1024}
1025
1026/*
1027 * Flush any TX data submitted for DMA and PIO. Called when the
1028 * TX circular buffer is reset.
1029 */
1030static void tegra_uart_flush_buffer(struct uart_port *u)
1031{
1032 struct tegra_uart_port *tup = to_tegra_uport(u);
1033
1034 tup->tx_bytes = 0;
1035 if (tup->tx_dma_chan)
1036 dmaengine_terminate_all(tup->tx_dma_chan);
1037}
1038
1039static void tegra_uart_shutdown(struct uart_port *u)
1040{
1041 struct tegra_uart_port *tup = to_tegra_uport(u);
1042
1043 tegra_uart_hw_deinit(tup);
1044
1045 tup->rx_in_progress = 0;
1046 tup->tx_in_progress = 0;
1047
1048 tegra_uart_dma_channel_free(tup, true);
1049 tegra_uart_dma_channel_free(tup, false);
1050 free_irq(u->irq, tup);
1051}
1052
1053static void tegra_uart_enable_ms(struct uart_port *u)
1054{
1055 struct tegra_uart_port *tup = to_tegra_uport(u);
1056
1057 if (tup->enable_modem_interrupt) {
1058 tup->ier_shadow |= UART_IER_MSI;
1059 tegra_uart_write(tup, tup->ier_shadow, UART_IER);
1060 }
1061}
1062
1063static void tegra_uart_set_termios(struct uart_port *u,
1064 struct ktermios *termios, struct ktermios *oldtermios)
1065{
1066 struct tegra_uart_port *tup = to_tegra_uport(u);
1067 unsigned int baud;
1068 unsigned long flags;
1069 unsigned int lcr;
1070 int symb_bit = 1;
1071 struct clk *parent_clk = clk_get_parent(tup->uart_clk);
1072 unsigned long parent_clk_rate = clk_get_rate(parent_clk);
1073 int max_divider = (tup->cdata->support_clk_src_div) ? 0x7FFF : 0xFFFF;
1074
1075 max_divider *= 16;
1076 spin_lock_irqsave(&u->lock, flags);
1077
1078 /* Changing configuration, it is safe to stop any rx now */
1079 if (tup->rts_active)
1080 set_rts(tup, false);
1081
1082 /* Clear all interrupts as configuration is going to be change */
1083 tegra_uart_write(tup, tup->ier_shadow | UART_IER_RDI, UART_IER);
1084 tegra_uart_read(tup, UART_IER);
1085 tegra_uart_write(tup, 0, UART_IER);
1086 tegra_uart_read(tup, UART_IER);
1087
1088 /* Parity */
1089 lcr = tup->lcr_shadow;
1090 lcr &= ~UART_LCR_PARITY;
1091
1092 /* CMSPAR isn't supported by this driver */
1093 termios->c_cflag &= ~CMSPAR;
1094
1095 if ((termios->c_cflag & PARENB) == PARENB) {
1096 symb_bit++;
1097 if (termios->c_cflag & PARODD) {
1098 lcr |= UART_LCR_PARITY;
1099 lcr &= ~UART_LCR_EPAR;
1100 lcr &= ~UART_LCR_SPAR;
1101 } else {
1102 lcr |= UART_LCR_PARITY;
1103 lcr |= UART_LCR_EPAR;
1104 lcr &= ~UART_LCR_SPAR;
1105 }
1106 }
1107
1108 lcr &= ~UART_LCR_WLEN8;
1109 switch (termios->c_cflag & CSIZE) {
1110 case CS5:
1111 lcr |= UART_LCR_WLEN5;
1112 symb_bit += 5;
1113 break;
1114 case CS6:
1115 lcr |= UART_LCR_WLEN6;
1116 symb_bit += 6;
1117 break;
1118 case CS7:
1119 lcr |= UART_LCR_WLEN7;
1120 symb_bit += 7;
1121 break;
1122 default:
1123 lcr |= UART_LCR_WLEN8;
1124 symb_bit += 8;
1125 break;
1126 }
1127
1128 /* Stop bits */
1129 if (termios->c_cflag & CSTOPB) {
1130 lcr |= UART_LCR_STOP;
1131 symb_bit += 2;
1132 } else {
1133 lcr &= ~UART_LCR_STOP;
1134 symb_bit++;
1135 }
1136
1137 tegra_uart_write(tup, lcr, UART_LCR);
1138 tup->lcr_shadow = lcr;
1139 tup->symb_bit = symb_bit;
1140
1141 /* Baud rate. */
1142 baud = uart_get_baud_rate(u, termios, oldtermios,
1143 parent_clk_rate/max_divider,
1144 parent_clk_rate/16);
1145 spin_unlock_irqrestore(&u->lock, flags);
1146 tegra_set_baudrate(tup, baud);
1147 if (tty_termios_baud_rate(termios))
1148 tty_termios_encode_baud_rate(termios, baud, baud);
1149 spin_lock_irqsave(&u->lock, flags);
1150
1151 /* Flow control */
1152 if (termios->c_cflag & CRTSCTS) {
1153 tup->mcr_shadow |= TEGRA_UART_MCR_CTS_EN;
1154 tup->mcr_shadow &= ~TEGRA_UART_MCR_RTS_EN;
1155 tegra_uart_write(tup, tup->mcr_shadow, UART_MCR);
1156 /* if top layer has asked to set rts active then do so here */
1157 if (tup->rts_active)
1158 set_rts(tup, true);
1159 } else {
1160 tup->mcr_shadow &= ~TEGRA_UART_MCR_CTS_EN;
1161 tup->mcr_shadow &= ~TEGRA_UART_MCR_RTS_EN;
1162 tegra_uart_write(tup, tup->mcr_shadow, UART_MCR);
1163 }
1164
1165 /* update the port timeout based on new settings */
1166 uart_update_timeout(u, termios->c_cflag, baud);
1167
1168 /* Make sure all write has completed */
1169 tegra_uart_read(tup, UART_IER);
1170
1171 /* Reenable interrupt */
1172 tegra_uart_write(tup, tup->ier_shadow, UART_IER);
1173 tegra_uart_read(tup, UART_IER);
1174
1175 spin_unlock_irqrestore(&u->lock, flags);
1176}
1177
1178static const char *tegra_uart_type(struct uart_port *u)
1179{
1180 return TEGRA_UART_TYPE;
1181}
1182
1183static const struct uart_ops tegra_uart_ops = {
1184 .tx_empty = tegra_uart_tx_empty,
1185 .set_mctrl = tegra_uart_set_mctrl,
1186 .get_mctrl = tegra_uart_get_mctrl,
1187 .stop_tx = tegra_uart_stop_tx,
1188 .start_tx = tegra_uart_start_tx,
1189 .stop_rx = tegra_uart_stop_rx,
1190 .flush_buffer = tegra_uart_flush_buffer,
1191 .enable_ms = tegra_uart_enable_ms,
1192 .break_ctl = tegra_uart_break_ctl,
1193 .startup = tegra_uart_startup,
1194 .shutdown = tegra_uart_shutdown,
1195 .set_termios = tegra_uart_set_termios,
1196 .type = tegra_uart_type,
1197 .request_port = tegra_uart_request_port,
1198 .release_port = tegra_uart_release_port,
1199};
1200
1201static struct uart_driver tegra_uart_driver = {
1202 .owner = THIS_MODULE,
1203 .driver_name = "tegra_hsuart",
1204 .dev_name = "ttyTHS",
1205 .cons = NULL,
1206 .nr = TEGRA_UART_MAXIMUM,
1207};
1208
1209static int tegra_uart_parse_dt(struct platform_device *pdev,
1210 struct tegra_uart_port *tup)
1211{
1212 struct device_node *np = pdev->dev.of_node;
1213 int port;
1214
1215 port = of_alias_get_id(np, "serial");
1216 if (port < 0) {
1217 dev_err(&pdev->dev, "failed to get alias id, errno %d\n", port);
1218 return port;
1219 }
1220 tup->uport.line = port;
1221
1222 tup->enable_modem_interrupt = of_property_read_bool(np,
1223 "nvidia,enable-modem-interrupt");
1224 return 0;
1225}
1226
1227static struct tegra_uart_chip_data tegra20_uart_chip_data = {
1228 .tx_fifo_full_status = false,
1229 .allow_txfifo_reset_fifo_mode = true,
1230 .support_clk_src_div = false,
1231};
1232
1233static struct tegra_uart_chip_data tegra30_uart_chip_data = {
1234 .tx_fifo_full_status = true,
1235 .allow_txfifo_reset_fifo_mode = false,
1236 .support_clk_src_div = true,
1237};
1238
1239static const struct of_device_id tegra_uart_of_match[] = {
1240 {
1241 .compatible = "nvidia,tegra30-hsuart",
1242 .data = &tegra30_uart_chip_data,
1243 }, {
1244 .compatible = "nvidia,tegra20-hsuart",
1245 .data = &tegra20_uart_chip_data,
1246 }, {
1247 },
1248};
1249MODULE_DEVICE_TABLE(of, tegra_uart_of_match);
1250
1251static int tegra_uart_probe(struct platform_device *pdev)
1252{
1253 struct tegra_uart_port *tup;
1254 struct uart_port *u;
1255 struct resource *resource;
1256 int ret;
1257 const struct tegra_uart_chip_data *cdata;
1258 const struct of_device_id *match;
1259
1260 match = of_match_device(tegra_uart_of_match, &pdev->dev);
1261 if (!match) {
1262 dev_err(&pdev->dev, "Error: No device match found\n");
1263 return -ENODEV;
1264 }
1265 cdata = match->data;
1266
1267 tup = devm_kzalloc(&pdev->dev, sizeof(*tup), GFP_KERNEL);
1268 if (!tup) {
1269 dev_err(&pdev->dev, "Failed to allocate memory for tup\n");
1270 return -ENOMEM;
1271 }
1272
1273 ret = tegra_uart_parse_dt(pdev, tup);
1274 if (ret < 0)
1275 return ret;
1276
1277 u = &tup->uport;
1278 u->dev = &pdev->dev;
1279 u->ops = &tegra_uart_ops;
1280 u->type = PORT_TEGRA;
1281 u->fifosize = 32;
1282 tup->cdata = cdata;
1283
1284 platform_set_drvdata(pdev, tup);
1285 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1286 if (!resource) {
1287 dev_err(&pdev->dev, "No IO memory resource\n");
1288 return -ENODEV;
1289 }
1290
1291 u->mapbase = resource->start;
1292 u->membase = devm_ioremap_resource(&pdev->dev, resource);
1293 if (IS_ERR(u->membase))
1294 return PTR_ERR(u->membase);
1295
1296 tup->uart_clk = devm_clk_get(&pdev->dev, NULL);
1297 if (IS_ERR(tup->uart_clk)) {
1298 dev_err(&pdev->dev, "Couldn't get the clock\n");
1299 return PTR_ERR(tup->uart_clk);
1300 }
1301
1302 tup->rst = devm_reset_control_get_exclusive(&pdev->dev, "serial");
1303 if (IS_ERR(tup->rst)) {
1304 dev_err(&pdev->dev, "Couldn't get the reset\n");
1305 return PTR_ERR(tup->rst);
1306 }
1307
1308 u->iotype = UPIO_MEM32;
1309 ret = platform_get_irq(pdev, 0);
1310 if (ret < 0) {
1311 dev_err(&pdev->dev, "Couldn't get IRQ\n");
1312 return ret;
1313 }
1314 u->irq = ret;
1315 u->regshift = 2;
1316 ret = uart_add_one_port(&tegra_uart_driver, u);
1317 if (ret < 0) {
1318 dev_err(&pdev->dev, "Failed to add uart port, err %d\n", ret);
1319 return ret;
1320 }
1321 return ret;
1322}
1323
1324static int tegra_uart_remove(struct platform_device *pdev)
1325{
1326 struct tegra_uart_port *tup = platform_get_drvdata(pdev);
1327 struct uart_port *u = &tup->uport;
1328
1329 uart_remove_one_port(&tegra_uart_driver, u);
1330 return 0;
1331}
1332
1333#ifdef CONFIG_PM_SLEEP
1334static int tegra_uart_suspend(struct device *dev)
1335{
1336 struct tegra_uart_port *tup = dev_get_drvdata(dev);
1337 struct uart_port *u = &tup->uport;
1338
1339 return uart_suspend_port(&tegra_uart_driver, u);
1340}
1341
1342static int tegra_uart_resume(struct device *dev)
1343{
1344 struct tegra_uart_port *tup = dev_get_drvdata(dev);
1345 struct uart_port *u = &tup->uport;
1346
1347 return uart_resume_port(&tegra_uart_driver, u);
1348}
1349#endif
1350
1351static const struct dev_pm_ops tegra_uart_pm_ops = {
1352 SET_SYSTEM_SLEEP_PM_OPS(tegra_uart_suspend, tegra_uart_resume)
1353};
1354
1355static struct platform_driver tegra_uart_platform_driver = {
1356 .probe = tegra_uart_probe,
1357 .remove = tegra_uart_remove,
1358 .driver = {
1359 .name = "serial-tegra",
1360 .of_match_table = tegra_uart_of_match,
1361 .pm = &tegra_uart_pm_ops,
1362 },
1363};
1364
1365static int __init tegra_uart_init(void)
1366{
1367 int ret;
1368
1369 ret = uart_register_driver(&tegra_uart_driver);
1370 if (ret < 0) {
1371 pr_err("Could not register %s driver\n",
1372 tegra_uart_driver.driver_name);
1373 return ret;
1374 }
1375
1376 ret = platform_driver_register(&tegra_uart_platform_driver);
1377 if (ret < 0) {
1378 pr_err("Uart platform driver register failed, e = %d\n", ret);
1379 uart_unregister_driver(&tegra_uart_driver);
1380 return ret;
1381 }
1382 return 0;
1383}
1384
1385static void __exit tegra_uart_exit(void)
1386{
1387 pr_info("Unloading tegra uart driver\n");
1388 platform_driver_unregister(&tegra_uart_platform_driver);
1389 uart_unregister_driver(&tegra_uart_driver);
1390}
1391
1392module_init(tegra_uart_init);
1393module_exit(tegra_uart_exit);
1394
1395MODULE_ALIAS("platform:serial-tegra");
1396MODULE_DESCRIPTION("High speed UART driver for tegra chipset");
1397MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
1398MODULE_LICENSE("GPL v2");