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

source code of linux/drivers/tty/serial/serial-tegra.c