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WIP FPC-III support
[linux/fpc-iii.git] / drivers / tty / serial / stm32-usart.c
blobf4de32d3f2afe4955749d0b4feff38f7e15efd58
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) Maxime Coquelin 2015
4 * Copyright (C) STMicroelectronics SA 2017
5 * Authors: Maxime Coquelin <mcoquelin.stm32@gmail.com>
6 * Gerald Baeza <gerald.baeza@st.com>
7 *
8 * Inspired by st-asc.c from STMicroelectronics (c)
9 */
10
11 #include <linux/clk.h>
12 #include <linux/console.h>
13 #include <linux/delay.h>
14 #include <linux/dma-direction.h>
15 #include <linux/dmaengine.h>
16 #include <linux/dma-mapping.h>
17 #include <linux/io.h>
18 #include <linux/iopoll.h>
19 #include <linux/irq.h>
20 #include <linux/module.h>
21 #include <linux/of.h>
22 #include <linux/of_platform.h>
23 #include <linux/pinctrl/consumer.h>
24 #include <linux/platform_device.h>
25 #include <linux/pm_runtime.h>
26 #include <linux/pm_wakeirq.h>
27 #include <linux/serial_core.h>
28 #include <linux/serial.h>
29 #include <linux/spinlock.h>
30 #include <linux/sysrq.h>
31 #include <linux/tty_flip.h>
32 #include <linux/tty.h>
33
34 #include "serial_mctrl_gpio.h"
35 #include "stm32-usart.h"
36
37 static void stm32_stop_tx(struct uart_port *port);
38 static void stm32_transmit_chars(struct uart_port *port);
39
40 static inline struct stm32_port *to_stm32_port(struct uart_port *port)
41 {
42 return container_of(port, struct stm32_port, port);
43 }
44
45 static void stm32_set_bits(struct uart_port *port, u32 reg, u32 bits)
46 {
47 u32 val;
48
49 val = readl_relaxed(port->membase + reg);
50 val |= bits;
51 writel_relaxed(val, port->membase + reg);
52 }
53
54 static void stm32_clr_bits(struct uart_port *port, u32 reg, u32 bits)
55 {
56 u32 val;
57
58 val = readl_relaxed(port->membase + reg);
59 val &= ~bits;
60 writel_relaxed(val, port->membase + reg);
61 }
62
63 static void stm32_config_reg_rs485(u32 *cr1, u32 *cr3, u32 delay_ADE,
64 u32 delay_DDE, u32 baud)
65 {
66 u32 rs485_deat_dedt;
67 u32 rs485_deat_dedt_max = (USART_CR1_DEAT_MASK >> USART_CR1_DEAT_SHIFT);
68 bool over8;
69
70 *cr3 |= USART_CR3_DEM;
71 over8 = *cr1 & USART_CR1_OVER8;
72
73 if (over8)
74 rs485_deat_dedt = delay_ADE * baud * 8;
75 else
76 rs485_deat_dedt = delay_ADE * baud * 16;
77
78 rs485_deat_dedt = DIV_ROUND_CLOSEST(rs485_deat_dedt, 1000);
79 rs485_deat_dedt = rs485_deat_dedt > rs485_deat_dedt_max ?
80 rs485_deat_dedt_max : rs485_deat_dedt;
81 rs485_deat_dedt = (rs485_deat_dedt << USART_CR1_DEAT_SHIFT) &
82 USART_CR1_DEAT_MASK;
83 *cr1 |= rs485_deat_dedt;
84
85 if (over8)
86 rs485_deat_dedt = delay_DDE * baud * 8;
87 else
88 rs485_deat_dedt = delay_DDE * baud * 16;
89
90 rs485_deat_dedt = DIV_ROUND_CLOSEST(rs485_deat_dedt, 1000);
91 rs485_deat_dedt = rs485_deat_dedt > rs485_deat_dedt_max ?
92 rs485_deat_dedt_max : rs485_deat_dedt;
93 rs485_deat_dedt = (rs485_deat_dedt << USART_CR1_DEDT_SHIFT) &
94 USART_CR1_DEDT_MASK;
95 *cr1 |= rs485_deat_dedt;
96 }
97
98 static int stm32_config_rs485(struct uart_port *port,
99 struct serial_rs485 *rs485conf)
100 {
101 struct stm32_port *stm32_port = to_stm32_port(port);
102 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
103 struct stm32_usart_config *cfg = &stm32_port->info->cfg;
104 u32 usartdiv, baud, cr1, cr3;
105 bool over8;
106
107 stm32_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
108
109 port->rs485 = *rs485conf;
110
111 rs485conf->flags |= SER_RS485_RX_DURING_TX;
112
113 if (rs485conf->flags & SER_RS485_ENABLED) {
114 cr1 = readl_relaxed(port->membase + ofs->cr1);
115 cr3 = readl_relaxed(port->membase + ofs->cr3);
116 usartdiv = readl_relaxed(port->membase + ofs->brr);
117 usartdiv = usartdiv & GENMASK(15, 0);
118 over8 = cr1 & USART_CR1_OVER8;
119
120 if (over8)
121 usartdiv = usartdiv | (usartdiv & GENMASK(4, 0))
122 << USART_BRR_04_R_SHIFT;
123
124 baud = DIV_ROUND_CLOSEST(port->uartclk, usartdiv);
125 stm32_config_reg_rs485(&cr1, &cr3,
126 rs485conf->delay_rts_before_send,
127 rs485conf->delay_rts_after_send, baud);
128
129 if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
130 cr3 &= ~USART_CR3_DEP;
131 rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
132 } else {
133 cr3 |= USART_CR3_DEP;
134 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
135 }
136
137 writel_relaxed(cr3, port->membase + ofs->cr3);
138 writel_relaxed(cr1, port->membase + ofs->cr1);
139 } else {
140 stm32_clr_bits(port, ofs->cr3, USART_CR3_DEM | USART_CR3_DEP);
141 stm32_clr_bits(port, ofs->cr1,
142 USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
143 }
144
145 stm32_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
146
147 return 0;
148 }
149
150 static int stm32_init_rs485(struct uart_port *port,
151 struct platform_device *pdev)
152 {
153 struct serial_rs485 *rs485conf = &port->rs485;
154
155 rs485conf->flags = 0;
156 rs485conf->delay_rts_before_send = 0;
157 rs485conf->delay_rts_after_send = 0;
158
159 if (!pdev->dev.of_node)
160 return -ENODEV;
161
162 return uart_get_rs485_mode(port);
163 }
164
165 static int stm32_pending_rx(struct uart_port *port, u32 *sr, int *last_res,
166 bool threaded)
167 {
168 struct stm32_port *stm32_port = to_stm32_port(port);
169 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
170 enum dma_status status;
171 struct dma_tx_state state;
172
173 *sr = readl_relaxed(port->membase + ofs->isr);
174
175 if (threaded && stm32_port->rx_ch) {
176 status = dmaengine_tx_status(stm32_port->rx_ch,
177 stm32_port->rx_ch->cookie,
178 &state);
179 if ((status == DMA_IN_PROGRESS) &&
180 (*last_res != state.residue))
181 return 1;
182 else
183 return 0;
184 } else if (*sr & USART_SR_RXNE) {
185 return 1;
186 }
187 return 0;
188 }
189
190 static unsigned long stm32_get_char(struct uart_port *port, u32 *sr,
191 int *last_res)
192 {
193 struct stm32_port *stm32_port = to_stm32_port(port);
194 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
195 unsigned long c;
196
197 if (stm32_port->rx_ch) {
198 c = stm32_port->rx_buf[RX_BUF_L - (*last_res)--];
199 if ((*last_res) == 0)
200 *last_res = RX_BUF_L;
201 } else {
202 c = readl_relaxed(port->membase + ofs->rdr);
203 /* apply RDR data mask */
204 c &= stm32_port->rdr_mask;
205 }
206
207 return c;
208 }
209
210 static void stm32_receive_chars(struct uart_port *port, bool threaded)
211 {
212 struct tty_port *tport = &port->state->port;
213 struct stm32_port *stm32_port = to_stm32_port(port);
214 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
215 unsigned long c;
216 u32 sr;
217 char flag;
218
219 if (irqd_is_wakeup_set(irq_get_irq_data(port->irq)))
220 pm_wakeup_event(tport->tty->dev, 0);
221
222 while (stm32_pending_rx(port, &sr, &stm32_port->last_res, threaded)) {
223 sr |= USART_SR_DUMMY_RX;
224 flag = TTY_NORMAL;
225
226 /*
227 * Status bits has to be cleared before reading the RDR:
228 * In FIFO mode, reading the RDR will pop the next data
229 * (if any) along with its status bits into the SR.
230 * Not doing so leads to misalignement between RDR and SR,
231 * and clear status bits of the next rx data.
232 *
233 * Clear errors flags for stm32f7 and stm32h7 compatible
234 * devices. On stm32f4 compatible devices, the error bit is
235 * cleared by the sequence [read SR - read DR].
236 */
237 if ((sr & USART_SR_ERR_MASK) && ofs->icr != UNDEF_REG)
238 writel_relaxed(sr & USART_SR_ERR_MASK,
239 port->membase + ofs->icr);
240
241 c = stm32_get_char(port, &sr, &stm32_port->last_res);
242 port->icount.rx++;
243 if (sr & USART_SR_ERR_MASK) {
244 if (sr & USART_SR_ORE) {
245 port->icount.overrun++;
246 } else if (sr & USART_SR_PE) {
247 port->icount.parity++;
248 } else if (sr & USART_SR_FE) {
249 /* Break detection if character is null */
250 if (!c) {
251 port->icount.brk++;
252 if (uart_handle_break(port))
253 continue;
254 } else {
255 port->icount.frame++;
256 }
257 }
258
259 sr &= port->read_status_mask;
260
261 if (sr & USART_SR_PE) {
262 flag = TTY_PARITY;
263 } else if (sr & USART_SR_FE) {
264 if (!c)
265 flag = TTY_BREAK;
266 else
267 flag = TTY_FRAME;
268 }
269 }
270
271 if (uart_handle_sysrq_char(port, c))
272 continue;
273 uart_insert_char(port, sr, USART_SR_ORE, c, flag);
274 }
275
276 spin_unlock(&port->lock);
277 tty_flip_buffer_push(tport);
278 spin_lock(&port->lock);
279 }
280
281 static void stm32_tx_dma_complete(void *arg)
282 {
283 struct uart_port *port = arg;
284 struct stm32_port *stm32port = to_stm32_port(port);
285 struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
286
287 stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
288 stm32port->tx_dma_busy = false;
289
290 /* Let's see if we have pending data to send */
291 stm32_transmit_chars(port);
292 }
293
294 static void stm32_tx_interrupt_enable(struct uart_port *port)
295 {
296 struct stm32_port *stm32_port = to_stm32_port(port);
297 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
298
299 /*
300 * Enables TX FIFO threashold irq when FIFO is enabled,
301 * or TX empty irq when FIFO is disabled
302 */
303 if (stm32_port->fifoen)
304 stm32_set_bits(port, ofs->cr3, USART_CR3_TXFTIE);
305 else
306 stm32_set_bits(port, ofs->cr1, USART_CR1_TXEIE);
307 }
308
309 static void stm32_tx_interrupt_disable(struct uart_port *port)
310 {
311 struct stm32_port *stm32_port = to_stm32_port(port);
312 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
313
314 if (stm32_port->fifoen)
315 stm32_clr_bits(port, ofs->cr3, USART_CR3_TXFTIE);
316 else
317 stm32_clr_bits(port, ofs->cr1, USART_CR1_TXEIE);
318 }
319
320 static void stm32_transmit_chars_pio(struct uart_port *port)
321 {
322 struct stm32_port *stm32_port = to_stm32_port(port);
323 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
324 struct circ_buf *xmit = &port->state->xmit;
325
326 if (stm32_port->tx_dma_busy) {
327 stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
328 stm32_port->tx_dma_busy = false;
329 }
330
331 while (!uart_circ_empty(xmit)) {
332 /* Check that TDR is empty before filling FIFO */
333 if (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE))
334 break;
335 writel_relaxed(xmit->buf[xmit->tail], port->membase + ofs->tdr);
336 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
337 port->icount.tx++;
338 }
339
340 /* rely on TXE irq (mask or unmask) for sending remaining data */
341 if (uart_circ_empty(xmit))
342 stm32_tx_interrupt_disable(port);
343 else
344 stm32_tx_interrupt_enable(port);
345 }
346
347 static void stm32_transmit_chars_dma(struct uart_port *port)
348 {
349 struct stm32_port *stm32port = to_stm32_port(port);
350 struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
351 struct circ_buf *xmit = &port->state->xmit;
352 struct dma_async_tx_descriptor *desc = NULL;
353 unsigned int count, i;
354
355 if (stm32port->tx_dma_busy)
356 return;
357
358 stm32port->tx_dma_busy = true;
359
360 count = uart_circ_chars_pending(xmit);
361
362 if (count > TX_BUF_L)
363 count = TX_BUF_L;
364
365 if (xmit->tail < xmit->head) {
366 memcpy(&stm32port->tx_buf[0], &xmit->buf[xmit->tail], count);
367 } else {
368 size_t one = UART_XMIT_SIZE - xmit->tail;
369 size_t two;
370
371 if (one > count)
372 one = count;
373 two = count - one;
374
375 memcpy(&stm32port->tx_buf[0], &xmit->buf[xmit->tail], one);
376 if (two)
377 memcpy(&stm32port->tx_buf[one], &xmit->buf[0], two);
378 }
379
380 desc = dmaengine_prep_slave_single(stm32port->tx_ch,
381 stm32port->tx_dma_buf,
382 count,
383 DMA_MEM_TO_DEV,
384 DMA_PREP_INTERRUPT);
385
386 if (!desc) {
387 for (i = count; i > 0; i--)
388 stm32_transmit_chars_pio(port);
389 return;
390 }
391
392 desc->callback = stm32_tx_dma_complete;
393 desc->callback_param = port;
394
395 /* Push current DMA TX transaction in the pending queue */
396 dmaengine_submit(desc);
397
398 /* Issue pending DMA TX requests */
399 dma_async_issue_pending(stm32port->tx_ch);
400
401 stm32_set_bits(port, ofs->cr3, USART_CR3_DMAT);
402
403 xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
404 port->icount.tx += count;
405 }
406
407 static void stm32_transmit_chars(struct uart_port *port)
408 {
409 struct stm32_port *stm32_port = to_stm32_port(port);
410 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
411 struct circ_buf *xmit = &port->state->xmit;
412
413 if (port->x_char) {
414 if (stm32_port->tx_dma_busy)
415 stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
416 writel_relaxed(port->x_char, port->membase + ofs->tdr);
417 port->x_char = 0;
418 port->icount.tx++;
419 if (stm32_port->tx_dma_busy)
420 stm32_set_bits(port, ofs->cr3, USART_CR3_DMAT);
421 return;
422 }
423
424 if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
425 stm32_tx_interrupt_disable(port);
426 return;
427 }
428
429 if (ofs->icr == UNDEF_REG)
430 stm32_clr_bits(port, ofs->isr, USART_SR_TC);
431 else
432 writel_relaxed(USART_ICR_TCCF, port->membase + ofs->icr);
433
434 if (stm32_port->tx_ch)
435 stm32_transmit_chars_dma(port);
436 else
437 stm32_transmit_chars_pio(port);
438
439 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
440 uart_write_wakeup(port);
441
442 if (uart_circ_empty(xmit))
443 stm32_tx_interrupt_disable(port);
444 }
445
446 static irqreturn_t stm32_interrupt(int irq, void *ptr)
447 {
448 struct uart_port *port = ptr;
449 struct stm32_port *stm32_port = to_stm32_port(port);
450 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
451 u32 sr;
452
453 spin_lock(&port->lock);
454
455 sr = readl_relaxed(port->membase + ofs->isr);
456
457 if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG)
458 writel_relaxed(USART_ICR_RTOCF,
459 port->membase + ofs->icr);
460
461 if ((sr & USART_SR_WUF) && (ofs->icr != UNDEF_REG))
462 writel_relaxed(USART_ICR_WUCF,
463 port->membase + ofs->icr);
464
465 if ((sr & USART_SR_RXNE) && !(stm32_port->rx_ch))
466 stm32_receive_chars(port, false);
467
468 if ((sr & USART_SR_TXE) && !(stm32_port->tx_ch))
469 stm32_transmit_chars(port);
470
471 spin_unlock(&port->lock);
472
473 if (stm32_port->rx_ch)
474 return IRQ_WAKE_THREAD;
475 else
476 return IRQ_HANDLED;
477 }
478
479 static irqreturn_t stm32_threaded_interrupt(int irq, void *ptr)
480 {
481 struct uart_port *port = ptr;
482 struct stm32_port *stm32_port = to_stm32_port(port);
483
484 spin_lock(&port->lock);
485
486 if (stm32_port->rx_ch)
487 stm32_receive_chars(port, true);
488
489 spin_unlock(&port->lock);
490
491 return IRQ_HANDLED;
492 }
493
494 static unsigned int stm32_tx_empty(struct uart_port *port)
495 {
496 struct stm32_port *stm32_port = to_stm32_port(port);
497 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
498
499 return readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE;
500 }
501
502 static void stm32_set_mctrl(struct uart_port *port, unsigned int mctrl)
503 {
504 struct stm32_port *stm32_port = to_stm32_port(port);
505 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
506
507 if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS))
508 stm32_set_bits(port, ofs->cr3, USART_CR3_RTSE);
509 else
510 stm32_clr_bits(port, ofs->cr3, USART_CR3_RTSE);
511
512 mctrl_gpio_set(stm32_port->gpios, mctrl);
513 }
514
515 static unsigned int stm32_get_mctrl(struct uart_port *port)
516 {
517 struct stm32_port *stm32_port = to_stm32_port(port);
518 unsigned int ret;
519
520 /* This routine is used to get signals of: DCD, DSR, RI, and CTS */
521 ret = TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
522
523 return mctrl_gpio_get(stm32_port->gpios, &ret);
524 }
525
526 static void stm32_enable_ms(struct uart_port *port)
527 {
528 mctrl_gpio_enable_ms(to_stm32_port(port)->gpios);
529 }
530
531 static void stm32_disable_ms(struct uart_port *port)
532 {
533 mctrl_gpio_disable_ms(to_stm32_port(port)->gpios);
534 }
535
536 /* Transmit stop */
537 static void stm32_stop_tx(struct uart_port *port)
538 {
539 struct stm32_port *stm32_port = to_stm32_port(port);
540 struct serial_rs485 *rs485conf = &port->rs485;
541
542 stm32_tx_interrupt_disable(port);
543
544 if (rs485conf->flags & SER_RS485_ENABLED) {
545 if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
546 mctrl_gpio_set(stm32_port->gpios,
547 stm32_port->port.mctrl & ~TIOCM_RTS);
548 } else {
549 mctrl_gpio_set(stm32_port->gpios,
550 stm32_port->port.mctrl | TIOCM_RTS);
551 }
552 }
553 }
554
555 /* There are probably characters waiting to be transmitted. */
556 static void stm32_start_tx(struct uart_port *port)
557 {
558 struct stm32_port *stm32_port = to_stm32_port(port);
559 struct serial_rs485 *rs485conf = &port->rs485;
560 struct circ_buf *xmit = &port->state->xmit;
561
562 if (uart_circ_empty(xmit))
563 return;
564
565 if (rs485conf->flags & SER_RS485_ENABLED) {
566 if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
567 mctrl_gpio_set(stm32_port->gpios,
568 stm32_port->port.mctrl | TIOCM_RTS);
569 } else {
570 mctrl_gpio_set(stm32_port->gpios,
571 stm32_port->port.mctrl & ~TIOCM_RTS);
572 }
573 }
574
575 stm32_transmit_chars(port);
576 }
577
578 /* Throttle the remote when input buffer is about to overflow. */
579 static void stm32_throttle(struct uart_port *port)
580 {
581 struct stm32_port *stm32_port = to_stm32_port(port);
582 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
583 unsigned long flags;
584
585 spin_lock_irqsave(&port->lock, flags);
586 stm32_clr_bits(port, ofs->cr1, stm32_port->cr1_irq);
587 if (stm32_port->cr3_irq)
588 stm32_clr_bits(port, ofs->cr3, stm32_port->cr3_irq);
589
590 spin_unlock_irqrestore(&port->lock, flags);
591 }
592
593 /* Unthrottle the remote, the input buffer can now accept data. */
594 static void stm32_unthrottle(struct uart_port *port)
595 {
596 struct stm32_port *stm32_port = to_stm32_port(port);
597 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
598 unsigned long flags;
599
600 spin_lock_irqsave(&port->lock, flags);
601 stm32_set_bits(port, ofs->cr1, stm32_port->cr1_irq);
602 if (stm32_port->cr3_irq)
603 stm32_set_bits(port, ofs->cr3, stm32_port->cr3_irq);
604
605 spin_unlock_irqrestore(&port->lock, flags);
606 }
607
608 /* Receive stop */
609 static void stm32_stop_rx(struct uart_port *port)
610 {
611 struct stm32_port *stm32_port = to_stm32_port(port);
612 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
613
614 stm32_clr_bits(port, ofs->cr1, stm32_port->cr1_irq);
615 if (stm32_port->cr3_irq)
616 stm32_clr_bits(port, ofs->cr3, stm32_port->cr3_irq);
617
618 }
619
620 /* Handle breaks - ignored by us */
621 static void stm32_break_ctl(struct uart_port *port, int break_state)
622 {
623 }
624
625 static int stm32_startup(struct uart_port *port)
626 {
627 struct stm32_port *stm32_port = to_stm32_port(port);
628 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
629 const char *name = to_platform_device(port->dev)->name;
630 u32 val;
631 int ret;
632
633 ret = request_threaded_irq(port->irq, stm32_interrupt,
634 stm32_threaded_interrupt,
635 IRQF_NO_SUSPEND, name, port);
636 if (ret)
637 return ret;
638
639 /* RX FIFO Flush */
640 if (ofs->rqr != UNDEF_REG)
641 stm32_set_bits(port, ofs->rqr, USART_RQR_RXFRQ);
642
643 /* Tx and RX FIFO configuration */
644 if (stm32_port->fifoen) {
645 val = readl_relaxed(port->membase + ofs->cr3);
646 val &= ~(USART_CR3_TXFTCFG_MASK | USART_CR3_RXFTCFG_MASK);
647 val |= USART_CR3_TXFTCFG_HALF << USART_CR3_TXFTCFG_SHIFT;
648 val |= USART_CR3_RXFTCFG_HALF << USART_CR3_RXFTCFG_SHIFT;
649 writel_relaxed(val, port->membase + ofs->cr3);
650 }
651
652 /* RX FIFO enabling */
653 val = stm32_port->cr1_irq | USART_CR1_RE;
654 if (stm32_port->fifoen)
655 val |= USART_CR1_FIFOEN;
656 stm32_set_bits(port, ofs->cr1, val);
657
658 return 0;
659 }
660
661 static void stm32_shutdown(struct uart_port *port)
662 {
663 struct stm32_port *stm32_port = to_stm32_port(port);
664 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
665 struct stm32_usart_config *cfg = &stm32_port->info->cfg;
666 u32 val, isr;
667 int ret;
668
669 /* Disable modem control interrupts */
670 stm32_disable_ms(port);
671
672 val = USART_CR1_TXEIE | USART_CR1_TE;
673 val |= stm32_port->cr1_irq | USART_CR1_RE;
674 val |= BIT(cfg->uart_enable_bit);
675 if (stm32_port->fifoen)
676 val |= USART_CR1_FIFOEN;
677
678 ret = readl_relaxed_poll_timeout(port->membase + ofs->isr,
679 isr, (isr & USART_SR_TC),
680 10, 100000);
681
682 if (ret)
683 dev_err(port->dev, "transmission complete not set\n");
684
685 stm32_clr_bits(port, ofs->cr1, val);
686
687 free_irq(port->irq, port);
688 }
689
690 static unsigned int stm32_get_databits(struct ktermios *termios)
691 {
692 unsigned int bits;
693
694 tcflag_t cflag = termios->c_cflag;
695
696 switch (cflag & CSIZE) {
697 /*
698 * CSIZE settings are not necessarily supported in hardware.
699 * CSIZE unsupported configurations are handled here to set word length
700 * to 8 bits word as default configuration and to print debug message.
701 */
702 case CS5:
703 bits = 5;
704 break;
705 case CS6:
706 bits = 6;
707 break;
708 case CS7:
709 bits = 7;
710 break;
711 /* default including CS8 */
712 default:
713 bits = 8;
714 break;
715 }
716
717 return bits;
718 }
719
720 static void stm32_set_termios(struct uart_port *port, struct ktermios *termios,
721 struct ktermios *old)
722 {
723 struct stm32_port *stm32_port = to_stm32_port(port);
724 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
725 struct stm32_usart_config *cfg = &stm32_port->info->cfg;
726 struct serial_rs485 *rs485conf = &port->rs485;
727 unsigned int baud, bits;
728 u32 usartdiv, mantissa, fraction, oversampling;
729 tcflag_t cflag = termios->c_cflag;
730 u32 cr1, cr2, cr3;
731 unsigned long flags;
732
733 if (!stm32_port->hw_flow_control)
734 cflag &= ~CRTSCTS;
735
736 baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 8);
737
738 spin_lock_irqsave(&port->lock, flags);
739
740 /* Stop serial port and reset value */
741 writel_relaxed(0, port->membase + ofs->cr1);
742
743 /* flush RX & TX FIFO */
744 if (ofs->rqr != UNDEF_REG)
745 stm32_set_bits(port, ofs->rqr,
746 USART_RQR_TXFRQ | USART_RQR_RXFRQ);
747
748 cr1 = USART_CR1_TE | USART_CR1_RE;
749 if (stm32_port->fifoen)
750 cr1 |= USART_CR1_FIFOEN;
751 cr2 = 0;
752 cr3 = readl_relaxed(port->membase + ofs->cr3);
753 cr3 &= USART_CR3_TXFTIE | USART_CR3_RXFTCFG_MASK | USART_CR3_RXFTIE
754 | USART_CR3_TXFTCFG_MASK;
755
756 if (cflag & CSTOPB)
757 cr2 |= USART_CR2_STOP_2B;
758
759 bits = stm32_get_databits(termios);
760 stm32_port->rdr_mask = (BIT(bits) - 1);
761
762 if (cflag & PARENB) {
763 bits++;
764 cr1 |= USART_CR1_PCE;
765 }
766
767 /*
768 * Word length configuration:
769 * CS8 + parity, 9 bits word aka [M1:M0] = 0b01
770 * CS7 or (CS6 + parity), 7 bits word aka [M1:M0] = 0b10
771 * CS8 or (CS7 + parity), 8 bits word aka [M1:M0] = 0b00
772 * M0 and M1 already cleared by cr1 initialization.
773 */
774 if (bits == 9)
775 cr1 |= USART_CR1_M0;
776 else if ((bits == 7) && cfg->has_7bits_data)
777 cr1 |= USART_CR1_M1;
778 else if (bits != 8)
779 dev_dbg(port->dev, "Unsupported data bits config: %u bits\n"
780 , bits);
781
782 if (ofs->rtor != UNDEF_REG && (stm32_port->rx_ch ||
783 stm32_port->fifoen)) {
784 if (cflag & CSTOPB)
785 bits = bits + 3; /* 1 start bit + 2 stop bits */
786 else
787 bits = bits + 2; /* 1 start bit + 1 stop bit */
788
789 /* RX timeout irq to occur after last stop bit + bits */
790 stm32_port->cr1_irq = USART_CR1_RTOIE;
791 writel_relaxed(bits, port->membase + ofs->rtor);
792 cr2 |= USART_CR2_RTOEN;
793 /* Not using dma, enable fifo threshold irq */
794 if (!stm32_port->rx_ch)
795 stm32_port->cr3_irq = USART_CR3_RXFTIE;
796 }
797
798 cr1 |= stm32_port->cr1_irq;
799 cr3 |= stm32_port->cr3_irq;
800
801 if (cflag & PARODD)
802 cr1 |= USART_CR1_PS;
803
804 port->status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS);
805 if (cflag & CRTSCTS) {
806 port->status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
807 cr3 |= USART_CR3_CTSE | USART_CR3_RTSE;
808 }
809
810 /* Handle modem control interrupts */
811 if (UART_ENABLE_MS(port, termios->c_cflag))
812 stm32_enable_ms(port);
813 else
814 stm32_disable_ms(port);
815
816 usartdiv = DIV_ROUND_CLOSEST(port->uartclk, baud);
817
818 /*
819 * The USART supports 16 or 8 times oversampling.
820 * By default we prefer 16 times oversampling, so that the receiver
821 * has a better tolerance to clock deviations.
822 * 8 times oversampling is only used to achieve higher speeds.
823 */
824 if (usartdiv < 16) {
825 oversampling = 8;
826 cr1 |= USART_CR1_OVER8;
827 stm32_set_bits(port, ofs->cr1, USART_CR1_OVER8);
828 } else {
829 oversampling = 16;
830 cr1 &= ~USART_CR1_OVER8;
831 stm32_clr_bits(port, ofs->cr1, USART_CR1_OVER8);
832 }
833
834 mantissa = (usartdiv / oversampling) << USART_BRR_DIV_M_SHIFT;
835 fraction = usartdiv % oversampling;
836 writel_relaxed(mantissa | fraction, port->membase + ofs->brr);
837
838 uart_update_timeout(port, cflag, baud);
839
840 port->read_status_mask = USART_SR_ORE;
841 if (termios->c_iflag & INPCK)
842 port->read_status_mask |= USART_SR_PE | USART_SR_FE;
843 if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
844 port->read_status_mask |= USART_SR_FE;
845
846 /* Characters to ignore */
847 port->ignore_status_mask = 0;
848 if (termios->c_iflag & IGNPAR)
849 port->ignore_status_mask = USART_SR_PE | USART_SR_FE;
850 if (termios->c_iflag & IGNBRK) {
851 port->ignore_status_mask |= USART_SR_FE;
852 /*
853 * If we're ignoring parity and break indicators,
854 * ignore overruns too (for real raw support).
855 */
856 if (termios->c_iflag & IGNPAR)
857 port->ignore_status_mask |= USART_SR_ORE;
858 }
859
860 /* Ignore all characters if CREAD is not set */
861 if ((termios->c_cflag & CREAD) == 0)
862 port->ignore_status_mask |= USART_SR_DUMMY_RX;
863
864 if (stm32_port->rx_ch)
865 cr3 |= USART_CR3_DMAR;
866
867 if (rs485conf->flags & SER_RS485_ENABLED) {
868 stm32_config_reg_rs485(&cr1, &cr3,
869 rs485conf->delay_rts_before_send,
870 rs485conf->delay_rts_after_send, baud);
871 if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
872 cr3 &= ~USART_CR3_DEP;
873 rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
874 } else {
875 cr3 |= USART_CR3_DEP;
876 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
877 }
878
879 } else {
880 cr3 &= ~(USART_CR3_DEM | USART_CR3_DEP);
881 cr1 &= ~(USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
882 }
883
884 writel_relaxed(cr3, port->membase + ofs->cr3);
885 writel_relaxed(cr2, port->membase + ofs->cr2);
886 writel_relaxed(cr1, port->membase + ofs->cr1);
887
888 stm32_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
889 spin_unlock_irqrestore(&port->lock, flags);
890 }
891
892 static const char *stm32_type(struct uart_port *port)
893 {
894 return (port->type == PORT_STM32) ? DRIVER_NAME : NULL;
895 }
896
897 static void stm32_release_port(struct uart_port *port)
898 {
899 }
900
901 static int stm32_request_port(struct uart_port *port)
902 {
903 return 0;
904 }
905
906 static void stm32_config_port(struct uart_port *port, int flags)
907 {
908 if (flags & UART_CONFIG_TYPE)
909 port->type = PORT_STM32;
910 }
911
912 static int
913 stm32_verify_port(struct uart_port *port, struct serial_struct *ser)
914 {
915 /* No user changeable parameters */
916 return -EINVAL;
917 }
918
919 static void stm32_pm(struct uart_port *port, unsigned int state,
920 unsigned int oldstate)
921 {
922 struct stm32_port *stm32port = container_of(port,
923 struct stm32_port, port);
924 struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
925 struct stm32_usart_config *cfg = &stm32port->info->cfg;
926 unsigned long flags = 0;
927
928 switch (state) {
929 case UART_PM_STATE_ON:
930 pm_runtime_get_sync(port->dev);
931 break;
932 case UART_PM_STATE_OFF:
933 spin_lock_irqsave(&port->lock, flags);
934 stm32_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
935 spin_unlock_irqrestore(&port->lock, flags);
936 pm_runtime_put_sync(port->dev);
937 break;
938 }
939 }
940
941 static const struct uart_ops stm32_uart_ops = {
942 .tx_empty = stm32_tx_empty,
943 .set_mctrl = stm32_set_mctrl,
944 .get_mctrl = stm32_get_mctrl,
945 .stop_tx = stm32_stop_tx,
946 .start_tx = stm32_start_tx,
947 .throttle = stm32_throttle,
948 .unthrottle = stm32_unthrottle,
949 .stop_rx = stm32_stop_rx,
950 .enable_ms = stm32_enable_ms,
951 .break_ctl = stm32_break_ctl,
952 .startup = stm32_startup,
953 .shutdown = stm32_shutdown,
954 .set_termios = stm32_set_termios,
955 .pm = stm32_pm,
956 .type = stm32_type,
957 .release_port = stm32_release_port,
958 .request_port = stm32_request_port,
959 .config_port = stm32_config_port,
960 .verify_port = stm32_verify_port,
961 };
962
963 static int stm32_init_port(struct stm32_port *stm32port,
964 struct platform_device *pdev)
965 {
966 struct uart_port *port = &stm32port->port;
967 struct resource *res;
968 int ret;
969
970 port->iotype = UPIO_MEM;
971 port->flags = UPF_BOOT_AUTOCONF;
972 port->ops = &stm32_uart_ops;
973 port->dev = &pdev->dev;
974 port->fifosize = stm32port->info->cfg.fifosize;
975 port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_STM32_CONSOLE);
976
977 ret = platform_get_irq(pdev, 0);
978 if (ret <= 0)
979 return ret ? : -ENODEV;
980 port->irq = ret;
981
982 port->rs485_config = stm32_config_rs485;
983
984 ret = stm32_init_rs485(port, pdev);
985 if (ret)
986 return ret;
987
988 if (stm32port->info->cfg.has_wakeup) {
989 stm32port->wakeirq = platform_get_irq_optional(pdev, 1);
990 if (stm32port->wakeirq <= 0 && stm32port->wakeirq != -ENXIO)
991 return stm32port->wakeirq ? : -ENODEV;
992 }
993
994 stm32port->fifoen = stm32port->info->cfg.has_fifo;
995
996 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
997 port->membase = devm_ioremap_resource(&pdev->dev, res);
998 if (IS_ERR(port->membase))
999 return PTR_ERR(port->membase);
1000 port->mapbase = res->start;
1001
1002 spin_lock_init(&port->lock);
1003
1004 stm32port->clk = devm_clk_get(&pdev->dev, NULL);
1005 if (IS_ERR(stm32port->clk))
1006 return PTR_ERR(stm32port->clk);
1007
1008 /* Ensure that clk rate is correct by enabling the clk */
1009 ret = clk_prepare_enable(stm32port->clk);
1010 if (ret)
1011 return ret;
1012
1013 stm32port->port.uartclk = clk_get_rate(stm32port->clk);
1014 if (!stm32port->port.uartclk) {
1015 ret = -EINVAL;
1016 goto err_clk;
1017 }
1018
1019 stm32port->gpios = mctrl_gpio_init(&stm32port->port, 0);
1020 if (IS_ERR(stm32port->gpios)) {
1021 ret = PTR_ERR(stm32port->gpios);
1022 goto err_clk;
1023 }
1024
1025 /* Both CTS/RTS gpios and "st,hw-flow-ctrl" should not be specified */
1026 if (stm32port->hw_flow_control) {
1027 if (mctrl_gpio_to_gpiod(stm32port->gpios, UART_GPIO_CTS) ||
1028 mctrl_gpio_to_gpiod(stm32port->gpios, UART_GPIO_RTS)) {
1029 dev_err(&pdev->dev, "Conflicting RTS/CTS config\n");
1030 ret = -EINVAL;
1031 goto err_clk;
1032 }
1033 }
1034
1035 return ret;
1036
1037 err_clk:
1038 clk_disable_unprepare(stm32port->clk);
1039
1040 return ret;
1041 }
1042
1043 static struct stm32_port *stm32_of_get_stm32_port(struct platform_device *pdev)
1044 {
1045 struct device_node *np = pdev->dev.of_node;
1046 int id;
1047
1048 if (!np)
1049 return NULL;
1050
1051 id = of_alias_get_id(np, "serial");
1052 if (id < 0) {
1053 dev_err(&pdev->dev, "failed to get alias id, errno %d\n", id);
1054 return NULL;
1055 }
1056
1057 if (WARN_ON(id >= STM32_MAX_PORTS))
1058 return NULL;
1059
1060 stm32_ports[id].hw_flow_control =
1061 of_property_read_bool (np, "st,hw-flow-ctrl") /*deprecated*/ ||
1062 of_property_read_bool (np, "uart-has-rtscts");
1063 stm32_ports[id].port.line = id;
1064 stm32_ports[id].cr1_irq = USART_CR1_RXNEIE;
1065 stm32_ports[id].cr3_irq = 0;
1066 stm32_ports[id].last_res = RX_BUF_L;
1067 return &stm32_ports[id];
1068 }
1069
1070 #ifdef CONFIG_OF
1071 static const struct of_device_id stm32_match[] = {
1072 { .compatible = "st,stm32-uart", .data = &stm32f4_info},
1073 { .compatible = "st,stm32f7-uart", .data = &stm32f7_info},
1074 { .compatible = "st,stm32h7-uart", .data = &stm32h7_info},
1075 {},
1076 };
1077
1078 MODULE_DEVICE_TABLE(of, stm32_match);
1079 #endif
1080
1081 static int stm32_of_dma_rx_probe(struct stm32_port *stm32port,
1082 struct platform_device *pdev)
1083 {
1084 struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
1085 struct uart_port *port = &stm32port->port;
1086 struct device *dev = &pdev->dev;
1087 struct dma_slave_config config;
1088 struct dma_async_tx_descriptor *desc = NULL;
1089 int ret;
1090
1091 /* Request DMA RX channel */
1092 stm32port->rx_ch = dma_request_slave_channel(dev, "rx");
1093 if (!stm32port->rx_ch) {
1094 dev_info(dev, "rx dma alloc failed\n");
1095 return -ENODEV;
1096 }
1097 stm32port->rx_buf = dma_alloc_coherent(&pdev->dev, RX_BUF_L,
1098 &stm32port->rx_dma_buf,
1099 GFP_KERNEL);
1100 if (!stm32port->rx_buf) {
1101 ret = -ENOMEM;
1102 goto alloc_err;
1103 }
1104
1105 /* Configure DMA channel */
1106 memset(&config, 0, sizeof(config));
1107 config.src_addr = port->mapbase + ofs->rdr;
1108 config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1109
1110 ret = dmaengine_slave_config(stm32port->rx_ch, &config);
1111 if (ret < 0) {
1112 dev_err(dev, "rx dma channel config failed\n");
1113 ret = -ENODEV;
1114 goto config_err;
1115 }
1116
1117 /* Prepare a DMA cyclic transaction */
1118 desc = dmaengine_prep_dma_cyclic(stm32port->rx_ch,
1119 stm32port->rx_dma_buf,
1120 RX_BUF_L, RX_BUF_P, DMA_DEV_TO_MEM,
1121 DMA_PREP_INTERRUPT);
1122 if (!desc) {
1123 dev_err(dev, "rx dma prep cyclic failed\n");
1124 ret = -ENODEV;
1125 goto config_err;
1126 }
1127
1128 /* No callback as dma buffer is drained on usart interrupt */
1129 desc->callback = NULL;
1130 desc->callback_param = NULL;
1131
1132 /* Push current DMA transaction in the pending queue */
1133 dmaengine_submit(desc);
1134
1135 /* Issue pending DMA requests */
1136 dma_async_issue_pending(stm32port->rx_ch);
1137
1138 return 0;
1139
1140 config_err:
1141 dma_free_coherent(&pdev->dev,
1142 RX_BUF_L, stm32port->rx_buf,
1143 stm32port->rx_dma_buf);
1144
1145 alloc_err:
1146 dma_release_channel(stm32port->rx_ch);
1147 stm32port->rx_ch = NULL;
1148
1149 return ret;
1150 }
1151
1152 static int stm32_of_dma_tx_probe(struct stm32_port *stm32port,
1153 struct platform_device *pdev)
1154 {
1155 struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
1156 struct uart_port *port = &stm32port->port;
1157 struct device *dev = &pdev->dev;
1158 struct dma_slave_config config;
1159 int ret;
1160
1161 stm32port->tx_dma_busy = false;
1162
1163 /* Request DMA TX channel */
1164 stm32port->tx_ch = dma_request_slave_channel(dev, "tx");
1165 if (!stm32port->tx_ch) {
1166 dev_info(dev, "tx dma alloc failed\n");
1167 return -ENODEV;
1168 }
1169 stm32port->tx_buf = dma_alloc_coherent(&pdev->dev, TX_BUF_L,
1170 &stm32port->tx_dma_buf,
1171 GFP_KERNEL);
1172 if (!stm32port->tx_buf) {
1173 ret = -ENOMEM;
1174 goto alloc_err;
1175 }
1176
1177 /* Configure DMA channel */
1178 memset(&config, 0, sizeof(config));
1179 config.dst_addr = port->mapbase + ofs->tdr;
1180 config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1181
1182 ret = dmaengine_slave_config(stm32port->tx_ch, &config);
1183 if (ret < 0) {
1184 dev_err(dev, "tx dma channel config failed\n");
1185 ret = -ENODEV;
1186 goto config_err;
1187 }
1188
1189 return 0;
1190
1191 config_err:
1192 dma_free_coherent(&pdev->dev,
1193 TX_BUF_L, stm32port->tx_buf,
1194 stm32port->tx_dma_buf);
1195
1196 alloc_err:
1197 dma_release_channel(stm32port->tx_ch);
1198 stm32port->tx_ch = NULL;
1199
1200 return ret;
1201 }
1202
1203 static int stm32_serial_probe(struct platform_device *pdev)
1204 {
1205 const struct of_device_id *match;
1206 struct stm32_port *stm32port;
1207 int ret;
1208
1209 stm32port = stm32_of_get_stm32_port(pdev);
1210 if (!stm32port)
1211 return -ENODEV;
1212
1213 match = of_match_device(stm32_match, &pdev->dev);
1214 if (match && match->data)
1215 stm32port->info = (struct stm32_usart_info *)match->data;
1216 else
1217 return -EINVAL;
1218
1219 ret = stm32_init_port(stm32port, pdev);
1220 if (ret)
1221 return ret;
1222
1223 if (stm32port->wakeirq > 0) {
1224 ret = device_init_wakeup(&pdev->dev, true);
1225 if (ret)
1226 goto err_uninit;
1227
1228 ret = dev_pm_set_dedicated_wake_irq(&pdev->dev,
1229 stm32port->wakeirq);
1230 if (ret)
1231 goto err_nowup;
1232
1233 device_set_wakeup_enable(&pdev->dev, false);
1234 }
1235
1236 ret = uart_add_one_port(&stm32_usart_driver, &stm32port->port);
1237 if (ret)
1238 goto err_wirq;
1239
1240 ret = stm32_of_dma_rx_probe(stm32port, pdev);
1241 if (ret)
1242 dev_info(&pdev->dev, "interrupt mode used for rx (no dma)\n");
1243
1244 ret = stm32_of_dma_tx_probe(stm32port, pdev);
1245 if (ret)
1246 dev_info(&pdev->dev, "interrupt mode used for tx (no dma)\n");
1247
1248 platform_set_drvdata(pdev, &stm32port->port);
1249
1250 pm_runtime_get_noresume(&pdev->dev);
1251 pm_runtime_set_active(&pdev->dev);
1252 pm_runtime_enable(&pdev->dev);
1253 pm_runtime_put_sync(&pdev->dev);
1254
1255 return 0;
1256
1257 err_wirq:
1258 if (stm32port->wakeirq > 0)
1259 dev_pm_clear_wake_irq(&pdev->dev);
1260
1261 err_nowup:
1262 if (stm32port->wakeirq > 0)
1263 device_init_wakeup(&pdev->dev, false);
1264
1265 err_uninit:
1266 clk_disable_unprepare(stm32port->clk);
1267
1268 return ret;
1269 }
1270
1271 static int stm32_serial_remove(struct platform_device *pdev)
1272 {
1273 struct uart_port *port = platform_get_drvdata(pdev);
1274 struct stm32_port *stm32_port = to_stm32_port(port);
1275 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1276 int err;
1277
1278 pm_runtime_get_sync(&pdev->dev);
1279
1280 stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAR);
1281
1282 if (stm32_port->rx_ch)
1283 dma_release_channel(stm32_port->rx_ch);
1284
1285 if (stm32_port->rx_dma_buf)
1286 dma_free_coherent(&pdev->dev,
1287 RX_BUF_L, stm32_port->rx_buf,
1288 stm32_port->rx_dma_buf);
1289
1290 stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
1291
1292 if (stm32_port->tx_ch)
1293 dma_release_channel(stm32_port->tx_ch);
1294
1295 if (stm32_port->tx_dma_buf)
1296 dma_free_coherent(&pdev->dev,
1297 TX_BUF_L, stm32_port->tx_buf,
1298 stm32_port->tx_dma_buf);
1299
1300 if (stm32_port->wakeirq > 0) {
1301 dev_pm_clear_wake_irq(&pdev->dev);
1302 device_init_wakeup(&pdev->dev, false);
1303 }
1304
1305 clk_disable_unprepare(stm32_port->clk);
1306
1307 err = uart_remove_one_port(&stm32_usart_driver, port);
1308
1309 pm_runtime_disable(&pdev->dev);
1310 pm_runtime_put_noidle(&pdev->dev);
1311
1312 return err;
1313 }
1314
1315
1316 #ifdef CONFIG_SERIAL_STM32_CONSOLE
1317 static void stm32_console_putchar(struct uart_port *port, int ch)
1318 {
1319 struct stm32_port *stm32_port = to_stm32_port(port);
1320 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1321
1322 while (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE))
1323 cpu_relax();
1324
1325 writel_relaxed(ch, port->membase + ofs->tdr);
1326 }
1327
1328 static void stm32_console_write(struct console *co, const char *s, unsigned cnt)
1329 {
1330 struct uart_port *port = &stm32_ports[co->index].port;
1331 struct stm32_port *stm32_port = to_stm32_port(port);
1332 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1333 struct stm32_usart_config *cfg = &stm32_port->info->cfg;
1334 unsigned long flags;
1335 u32 old_cr1, new_cr1;
1336 int locked = 1;
1337
1338 local_irq_save(flags);
1339 if (port->sysrq)
1340 locked = 0;
1341 else if (oops_in_progress)
1342 locked = spin_trylock(&port->lock);
1343 else
1344 spin_lock(&port->lock);
1345
1346 /* Save and disable interrupts, enable the transmitter */
1347 old_cr1 = readl_relaxed(port->membase + ofs->cr1);
1348 new_cr1 = old_cr1 & ~USART_CR1_IE_MASK;
1349 new_cr1 |= USART_CR1_TE | BIT(cfg->uart_enable_bit);
1350 writel_relaxed(new_cr1, port->membase + ofs->cr1);
1351
1352 uart_console_write(port, s, cnt, stm32_console_putchar);
1353
1354 /* Restore interrupt state */
1355 writel_relaxed(old_cr1, port->membase + ofs->cr1);
1356
1357 if (locked)
1358 spin_unlock(&port->lock);
1359 local_irq_restore(flags);
1360 }
1361
1362 static int stm32_console_setup(struct console *co, char *options)
1363 {
1364 struct stm32_port *stm32port;
1365 int baud = 9600;
1366 int bits = 8;
1367 int parity = 'n';
1368 int flow = 'n';
1369
1370 if (co->index >= STM32_MAX_PORTS)
1371 return -ENODEV;
1372
1373 stm32port = &stm32_ports[co->index];
1374
1375 /*
1376 * This driver does not support early console initialization
1377 * (use ARM early printk support instead), so we only expect
1378 * this to be called during the uart port registration when the
1379 * driver gets probed and the port should be mapped at that point.
1380 */
1381 if (stm32port->port.mapbase == 0 || stm32port->port.membase == NULL)
1382 return -ENXIO;
1383
1384 if (options)
1385 uart_parse_options(options, &baud, &parity, &bits, &flow);
1386
1387 return uart_set_options(&stm32port->port, co, baud, parity, bits, flow);
1388 }
1389
1390 static struct console stm32_console = {
1391 .name = STM32_SERIAL_NAME,
1392 .device = uart_console_device,
1393 .write = stm32_console_write,
1394 .setup = stm32_console_setup,
1395 .flags = CON_PRINTBUFFER,
1396 .index = -1,
1397 .data = &stm32_usart_driver,
1398 };
1399
1400 #define STM32_SERIAL_CONSOLE (&stm32_console)
1401
1402 #else
1403 #define STM32_SERIAL_CONSOLE NULL
1404 #endif /* CONFIG_SERIAL_STM32_CONSOLE */
1405
1406 static struct uart_driver stm32_usart_driver = {
1407 .driver_name = DRIVER_NAME,
1408 .dev_name = STM32_SERIAL_NAME,
1409 .major = 0,
1410 .minor = 0,
1411 .nr = STM32_MAX_PORTS,
1412 .cons = STM32_SERIAL_CONSOLE,
1413 };
1414
1415 static void __maybe_unused stm32_serial_enable_wakeup(struct uart_port *port,
1416 bool enable)
1417 {
1418 struct stm32_port *stm32_port = to_stm32_port(port);
1419 struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1420 struct stm32_usart_config *cfg = &stm32_port->info->cfg;
1421 u32 val;
1422
1423 if (stm32_port->wakeirq <= 0)
1424 return;
1425
1426 if (enable) {
1427 stm32_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
1428 stm32_set_bits(port, ofs->cr1, USART_CR1_UESM);
1429 val = readl_relaxed(port->membase + ofs->cr3);
1430 val &= ~USART_CR3_WUS_MASK;
1431 /* Enable Wake up interrupt from low power on start bit */
1432 val |= USART_CR3_WUS_START_BIT | USART_CR3_WUFIE;
1433 writel_relaxed(val, port->membase + ofs->cr3);
1434 stm32_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
1435 } else {
1436 stm32_clr_bits(port, ofs->cr1, USART_CR1_UESM);
1437 }
1438 }
1439
1440 static int __maybe_unused stm32_serial_suspend(struct device *dev)
1441 {
1442 struct uart_port *port = dev_get_drvdata(dev);
1443
1444 uart_suspend_port(&stm32_usart_driver, port);
1445
1446 if (device_may_wakeup(dev))
1447 stm32_serial_enable_wakeup(port, true);
1448 else
1449 stm32_serial_enable_wakeup(port, false);
1450
1451 /*
1452 * When "no_console_suspend" is enabled, keep the pinctrl default state
1453 * and rely on bootloader stage to restore this state upon resume.
1454 * Otherwise, apply the idle or sleep states depending on wakeup
1455 * capabilities.
1456 */
1457 if (console_suspend_enabled || !uart_console(port)) {
1458 if (device_may_wakeup(dev))
1459 pinctrl_pm_select_idle_state(dev);
1460 else
1461 pinctrl_pm_select_sleep_state(dev);
1462 }
1463
1464 return 0;
1465 }
1466
1467 static int __maybe_unused stm32_serial_resume(struct device *dev)
1468 {
1469 struct uart_port *port = dev_get_drvdata(dev);
1470
1471 pinctrl_pm_select_default_state(dev);
1472
1473 if (device_may_wakeup(dev))
1474 stm32_serial_enable_wakeup(port, false);
1475
1476 return uart_resume_port(&stm32_usart_driver, port);
1477 }
1478
1479 static int __maybe_unused stm32_serial_runtime_suspend(struct device *dev)
1480 {
1481 struct uart_port *port = dev_get_drvdata(dev);
1482 struct stm32_port *stm32port = container_of(port,
1483 struct stm32_port, port);
1484
1485 clk_disable_unprepare(stm32port->clk);
1486
1487 return 0;
1488 }
1489
1490 static int __maybe_unused stm32_serial_runtime_resume(struct device *dev)
1491 {
1492 struct uart_port *port = dev_get_drvdata(dev);
1493 struct stm32_port *stm32port = container_of(port,
1494 struct stm32_port, port);
1495
1496 return clk_prepare_enable(stm32port->clk);
1497 }
1498
1499 static const struct dev_pm_ops stm32_serial_pm_ops = {
1500 SET_RUNTIME_PM_OPS(stm32_serial_runtime_suspend,
1501 stm32_serial_runtime_resume, NULL)
1502 SET_SYSTEM_SLEEP_PM_OPS(stm32_serial_suspend, stm32_serial_resume)
1503 };
1504
1505 static struct platform_driver stm32_serial_driver = {
1506 .probe = stm32_serial_probe,
1507 .remove = stm32_serial_remove,
1508 .driver = {
1509 .name = DRIVER_NAME,
1510 .pm = &stm32_serial_pm_ops,
1511 .of_match_table = of_match_ptr(stm32_match),
1512 },
1513 };
1514
1515 static int __init usart_init(void)
1516 {
1517 static char banner[] __initdata = "STM32 USART driver initialized";
1518 int ret;
1519
1520 pr_info("%s\n", banner);
1521
1522 ret = uart_register_driver(&stm32_usart_driver);
1523 if (ret)
1524 return ret;
1525
1526 ret = platform_driver_register(&stm32_serial_driver);
1527 if (ret)
1528 uart_unregister_driver(&stm32_usart_driver);
1529
1530 return ret;
1531 }
1532
1533 static void __exit usart_exit(void)
1534 {
1535 platform_driver_unregister(&stm32_serial_driver);
1536 uart_unregister_driver(&stm32_usart_driver);
1537 }
1538
1539 module_init(usart_init);
1540 module_exit(usart_exit);
1541
1542 MODULE_ALIAS("platform:" DRIVER_NAME);
1543 MODULE_DESCRIPTION("STMicroelectronics STM32 serial port driver");
1544 MODULE_LICENSE("GPL v2");
Linux with added FPC-III support