]> git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blame - drivers/tty/serial/st-asc.c
projects / mirror_ubuntu-artful-kernel.git / blame
? search:
summary | shortlog | log | commit | commitdiff | tree
blob | blame (incremental) | history | HEAD
Merge tag 'linux-kselftest-4.13-rc6-fixes' of git://git.kernel.org/pub/scm/linux...
[mirror_ubuntu-artful-kernel.git] / drivers / tty / serial / st-asc.c
CommitLineData
c4b05856
SK		 1/*
2 * st-asc.c: ST Asynchronous serial controller (ASC) driver
3 *
4 * Copyright (C) 2003-2013 STMicroelectronics (R&D) Limited
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 */
12
13#if defined(CONFIG_SERIAL_ST_ASC_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
14#define SUPPORT_SYSRQ
15#endif
16
17#include <linux/module.h>
18#include <linux/serial.h>
19#include <linux/console.h>
20#include <linux/sysrq.h>
6929cb00 21#include <linux/pinctrl/consumer.h>
c4b05856
SK		 22#include <linux/platform_device.h>
23#include <linux/io.h>
24#include <linux/irq.h>
25#include <linux/tty.h>
26#include <linux/tty_flip.h>
27#include <linux/delay.h>
28#include <linux/spinlock.h>
29#include <linux/pm_runtime.h>
30#include <linux/of.h>
31#include <linux/of_platform.h>
32#include <linux/serial_core.h>
33#include <linux/clk.h>
a4f6072f 34#include <linux/gpio/consumer.h>
c4b05856
SK		 35
36#define DRIVER_NAME "st-asc"
37#define ASC_SERIAL_NAME "ttyAS"
38#define ASC_FIFO_SIZE 16
39#define ASC_MAX_PORTS 8
40
6929cb00
LJ		 41/* Pinctrl states */
42#define DEFAULT 0
43#define NO_HW_FLOWCTRL 1
44
c4b05856
SK		 45struct asc_port {
46 struct uart_port port;
a4f6072f 47 struct gpio_desc *rts;
c4b05856 48 struct clk *clk;
6929cb00
LJ		 49 struct pinctrl *pinctrl;
50 struct pinctrl_state *states[2];
c4b05856
SK		 51 unsigned int hw_flow_control:1;
52 unsigned int force_m1:1;
53};
54
55static struct asc_port asc_ports[ASC_MAX_PORTS];
56static struct uart_driver asc_uart_driver;
57
58/*---- UART Register definitions ------------------------------*/
59
60/* Register offsets */
61
62#define ASC_BAUDRATE 0x00
63#define ASC_TXBUF 0x04
64#define ASC_RXBUF 0x08
65#define ASC_CTL 0x0C
66#define ASC_INTEN 0x10
67#define ASC_STA 0x14
68#define ASC_GUARDTIME 0x18
69#define ASC_TIMEOUT 0x1C
70#define ASC_TXRESET 0x20
71#define ASC_RXRESET 0x24
72#define ASC_RETRIES 0x28
73
74/* ASC_RXBUF */
75#define ASC_RXBUF_PE 0x100
76#define ASC_RXBUF_FE 0x200
77/**
78 * Some of status comes from higher bits of the character and some come from
79 * the status register. Combining both of them in to single status using dummy
80 * bits.
81 */
82#define ASC_RXBUF_DUMMY_RX 0x10000
83#define ASC_RXBUF_DUMMY_BE 0x20000
84#define ASC_RXBUF_DUMMY_OE 0x40000
85
86/* ASC_CTL */
87
88#define ASC_CTL_MODE_MSK 0x0007
89#define ASC_CTL_MODE_8BIT 0x0001
90#define ASC_CTL_MODE_7BIT_PAR 0x0003
91#define ASC_CTL_MODE_9BIT 0x0004
92#define ASC_CTL_MODE_8BIT_WKUP 0x0005
93#define ASC_CTL_MODE_8BIT_PAR 0x0007
94#define ASC_CTL_STOP_MSK 0x0018
95#define ASC_CTL_STOP_HALFBIT 0x0000
96#define ASC_CTL_STOP_1BIT 0x0008
97#define ASC_CTL_STOP_1_HALFBIT 0x0010
98#define ASC_CTL_STOP_2BIT 0x0018
99#define ASC_CTL_PARITYODD 0x0020
100#define ASC_CTL_LOOPBACK 0x0040
101#define ASC_CTL_RUN 0x0080
102#define ASC_CTL_RXENABLE 0x0100
103#define ASC_CTL_SCENABLE 0x0200
104#define ASC_CTL_FIFOENABLE 0x0400
105#define ASC_CTL_CTSENABLE 0x0800
106#define ASC_CTL_BAUDMODE 0x1000
107
108/* ASC_GUARDTIME */
109
110#define ASC_GUARDTIME_MSK 0x00FF
111
112/* ASC_INTEN */
113
114#define ASC_INTEN_RBE 0x0001
115#define ASC_INTEN_TE 0x0002
116#define ASC_INTEN_THE 0x0004
117#define ASC_INTEN_PE 0x0008
118#define ASC_INTEN_FE 0x0010
119#define ASC_INTEN_OE 0x0020
120#define ASC_INTEN_TNE 0x0040
121#define ASC_INTEN_TOI 0x0080
122#define ASC_INTEN_RHF 0x0100
123
124/* ASC_RETRIES */
125
126#define ASC_RETRIES_MSK 0x00FF
127
128/* ASC_RXBUF */
129
130#define ASC_RXBUF_MSK 0x03FF
131
132/* ASC_STA */
133
134#define ASC_STA_RBF 0x0001
135#define ASC_STA_TE 0x0002
136#define ASC_STA_THE 0x0004
137#define ASC_STA_PE 0x0008
138#define ASC_STA_FE 0x0010
139#define ASC_STA_OE 0x0020
140#define ASC_STA_TNE 0x0040
141#define ASC_STA_TOI 0x0080
142#define ASC_STA_RHF 0x0100
143#define ASC_STA_TF 0x0200
144#define ASC_STA_NKD 0x0400
145
146/* ASC_TIMEOUT */
147
148#define ASC_TIMEOUT_MSK 0x00FF
149
150/* ASC_TXBUF */
151
152#define ASC_TXBUF_MSK 0x01FF
153
154/*---- Inline function definitions ---------------------------*/
155
156static inline struct asc_port *to_asc_port(struct uart_port *port)
157{
158 return container_of(port, struct asc_port, port);
159}
160
161static inline u32 asc_in(struct uart_port *port, u32 offset)
162{
daea65a7 163#ifdef readl_relaxed
08177ece 164 return readl_relaxed(port->membase + offset);
daea65a7
DT		 165#else
166 return readl(port->membase + offset);
167#endif
c4b05856
SK		 168}
169
170static inline void asc_out(struct uart_port *port, u32 offset, u32 value)
171{
08177ece
DT		 172#ifdef writel_relaxed
173 writel_relaxed(value, port->membase + offset);
174#else
c4b05856 175 writel(value, port->membase + offset);
08177ece 176#endif
c4b05856
SK		 177}
178
179/*
180 * Some simple utility functions to enable and disable interrupts.
181 * Note that these need to be called with interrupts disabled.
182 */
183static inline void asc_disable_tx_interrupts(struct uart_port *port)
184{
185 u32 intenable = asc_in(port, ASC_INTEN) & ~ASC_INTEN_THE;
186 asc_out(port, ASC_INTEN, intenable);
187 (void)asc_in(port, ASC_INTEN); /* Defeat bus write posting */
188}
189
190static inline void asc_enable_tx_interrupts(struct uart_port *port)
191{
192 u32 intenable = asc_in(port, ASC_INTEN) | ASC_INTEN_THE;
193 asc_out(port, ASC_INTEN, intenable);
194}
195
196static inline void asc_disable_rx_interrupts(struct uart_port *port)
197{
198 u32 intenable = asc_in(port, ASC_INTEN) & ~ASC_INTEN_RBE;
199 asc_out(port, ASC_INTEN, intenable);
200 (void)asc_in(port, ASC_INTEN); /* Defeat bus write posting */
201}
202
203static inline void asc_enable_rx_interrupts(struct uart_port *port)
204{
205 u32 intenable = asc_in(port, ASC_INTEN) | ASC_INTEN_RBE;
206 asc_out(port, ASC_INTEN, intenable);
207}
208
209static inline u32 asc_txfifo_is_empty(struct uart_port *port)
210{
211 return asc_in(port, ASC_STA) & ASC_STA_TE;
212}
213
1ffcd67d 214static inline u32 asc_txfifo_is_half_empty(struct uart_port *port)
c4b05856 215{
1ffcd67d 216 return asc_in(port, ASC_STA) & ASC_STA_THE;
c4b05856
SK		 217}
218
219static inline const char *asc_port_name(struct uart_port *port)
220{
221 return to_platform_device(port->dev)->name;
222}
223
224/*----------------------------------------------------------------------*/
225
226/*
227 * This section contains code to support the use of the ASC as a
228 * generic serial port.
229 */
230
231static inline unsigned asc_hw_txroom(struct uart_port *port)
232{
233 u32 status = asc_in(port, ASC_STA);
234
235 if (status & ASC_STA_THE)
236 return port->fifosize / 2;
237 else if (!(status & ASC_STA_TF))
238 return 1;
239
240 return 0;
241}
242
243/*
244 * Start transmitting chars.
245 * This is called from both interrupt and task level.
246 * Either way interrupts are disabled.
247 */
248static void asc_transmit_chars(struct uart_port *port)
249{
250 struct circ_buf *xmit = &port->state->xmit;
251 int txroom;
252 unsigned char c;
253
254 txroom = asc_hw_txroom(port);
255
256 if ((txroom != 0) && port->x_char) {
257 c = port->x_char;
258 port->x_char = 0;
259 asc_out(port, ASC_TXBUF, c);
260 port->icount.tx++;
261 txroom = asc_hw_txroom(port);
262 }
263
264 if (uart_tx_stopped(port)) {
265 /*
266 * We should try and stop the hardware here, but I
267 * don't think the ASC has any way to do that.
268 */
269 asc_disable_tx_interrupts(port);
270 return;
271 }
272
273 if (uart_circ_empty(xmit)) {
274 asc_disable_tx_interrupts(port);
275 return;
276 }
277
278 if (txroom == 0)
279 return;
280
281 do {
282 c = xmit->buf[xmit->tail];
283 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
284 asc_out(port, ASC_TXBUF, c);
285 port->icount.tx++;
286 txroom--;
287 } while ((txroom > 0) && (!uart_circ_empty(xmit)));
288
289 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
290 uart_write_wakeup(port);
291
292 if (uart_circ_empty(xmit))
293 asc_disable_tx_interrupts(port);
294}
295
296static void asc_receive_chars(struct uart_port *port)
297{
298 struct tty_port *tport = &port->state->port;
5ab066e5 299 unsigned long status, mode;
c4b05856
SK		 300 unsigned long c = 0;
301 char flag;
5ab066e5
LJ		 302 bool ignore_pe = false;
303
304 /*
305 * Datasheet states: If the MODE field selects an 8-bit frame then
306 * this [parity error] bit is undefined. Software should ignore this
307 * bit when reading 8-bit frames.
308 */
309 mode = asc_in(port, ASC_CTL) & ASC_CTL_MODE_MSK;
310 if (mode == ASC_CTL_MODE_8BIT || mode == ASC_CTL_MODE_8BIT_PAR)
311 ignore_pe = true;
c4b05856
SK		 312
313 if (port->irq_wake)
314 pm_wakeup_event(tport->tty->dev, 0);
315
316 while ((status = asc_in(port, ASC_STA)) & ASC_STA_RBF) {
317 c = asc_in(port, ASC_RXBUF) | ASC_RXBUF_DUMMY_RX;
318 flag = TTY_NORMAL;
319 port->icount.rx++;
320
5ab066e5
LJ		 321 if (status & ASC_STA_OE || c & ASC_RXBUF_FE ||
322 (c & ASC_RXBUF_PE && !ignore_pe)) {
c4b05856
SK		 323
324 if (c & ASC_RXBUF_FE) {
c3c00b6f 325 if (c == (ASC_RXBUF_FE | ASC_RXBUF_DUMMY_RX)) {
c4b05856
SK		 326 port->icount.brk++;
327 if (uart_handle_break(port))
328 continue;
329 c |= ASC_RXBUF_DUMMY_BE;
330 } else {
331 port->icount.frame++;
332 }
333 } else if (c & ASC_RXBUF_PE) {
334 port->icount.parity++;
335 }
336 /*
337 * Reading any data from the RX FIFO clears the
338 * overflow error condition.
339 */
340 if (status & ASC_STA_OE) {
341 port->icount.overrun++;
342 c |= ASC_RXBUF_DUMMY_OE;
343 }
344
345 c &= port->read_status_mask;
346
347 if (c & ASC_RXBUF_DUMMY_BE)
348 flag = TTY_BREAK;
349 else if (c & ASC_RXBUF_PE)
350 flag = TTY_PARITY;
351 else if (c & ASC_RXBUF_FE)
352 flag = TTY_FRAME;
353 }
354
c3c00b6f 355 if (uart_handle_sysrq_char(port, c & 0xff))
c4b05856
SK		 356 continue;
357
358 uart_insert_char(port, c, ASC_RXBUF_DUMMY_OE, c & 0xff, flag);
359 }
360
361 /* Tell the rest of the system the news. New characters! */
362 tty_flip_buffer_push(tport);
363}
364
365static irqreturn_t asc_interrupt(int irq, void *ptr)
366{
367 struct uart_port *port = ptr;
368 u32 status;
369
370 spin_lock(&port->lock);
371
372 status = asc_in(port, ASC_STA);
373
374 if (status & ASC_STA_RBF) {
375 /* Receive FIFO not empty */
376 asc_receive_chars(port);
377 }
378
379 if ((status & ASC_STA_THE) &&
380 (asc_in(port, ASC_INTEN) & ASC_INTEN_THE)) {
381 /* Transmitter FIFO at least half empty */
382 asc_transmit_chars(port);
383 }
384
385 spin_unlock(&port->lock);
386
387 return IRQ_HANDLED;
388}
389
390/*----------------------------------------------------------------------*/
391
392/*
393 * UART Functions
394 */
395
396static unsigned int asc_tx_empty(struct uart_port *port)
397{
398 return asc_txfifo_is_empty(port) ? TIOCSER_TEMT : 0;
399}
400
401static void asc_set_mctrl(struct uart_port *port, unsigned int mctrl)
402{
a4f6072f
LJ		 403 struct asc_port *ascport = to_asc_port(port);
404
c4b05856 405 /*
a4f6072f
LJ		 406 * This routine is used for seting signals of: DTR, DCD, CTS and RTS.
407 * We use ASC's hardware for CTS/RTS when hardware flow-control is
408 * enabled, however if the RTS line is required for another purpose,
409 * commonly controlled using HUP from userspace, then we need to toggle
410 * it manually, using GPIO.
411 *
412 * Some boards also have DTR and DCD implemented using PIO pins, code to
413 * do this should be hooked in here.
c4b05856 414 */
a4f6072f
LJ		 415
416 if (!ascport->rts)
417 return;
418
419 /* If HW flow-control is enabled, we can't fiddle with the RTS line */
420 if (asc_in(port, ASC_CTL) & ASC_CTL_CTSENABLE)
421 return;
422
423 gpiod_set_value(ascport->rts, mctrl & TIOCM_RTS);
c4b05856
SK		 424}
425
426static unsigned int asc_get_mctrl(struct uart_port *port)
427{
428 /*
429 * This routine is used for geting signals of: DTR, DCD, DSR, RI,
430 * and CTS/RTS
431 */
432 return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
433}
434
435/* There are probably characters waiting to be transmitted. */
436static void asc_start_tx(struct uart_port *port)
437{
438 struct circ_buf *xmit = &port->state->xmit;
439
440 if (!uart_circ_empty(xmit))
441 asc_enable_tx_interrupts(port);
442}
443
444/* Transmit stop */
445static void asc_stop_tx(struct uart_port *port)
446{
447 asc_disable_tx_interrupts(port);
448}
449
450/* Receive stop */
451static void asc_stop_rx(struct uart_port *port)
452{
453 asc_disable_rx_interrupts(port);
454}
455
c4b05856
SK		 456/* Handle breaks - ignored by us */
457static void asc_break_ctl(struct uart_port *port, int break_state)
458{
459 /* Nothing here yet .. */
460}
461
462/*
463 * Enable port for reception.
464 */
465static int asc_startup(struct uart_port *port)
466{
616ea8d2 467 if (request_irq(port->irq, asc_interrupt, 0,
c4b05856
SK		 468 asc_port_name(port), port)) {
469 dev_err(port->dev, "cannot allocate irq.\n");
470 return -ENODEV;
471 }
472
473 asc_transmit_chars(port);
474 asc_enable_rx_interrupts(port);
475
476 return 0;
477}
478
479static void asc_shutdown(struct uart_port *port)
480{
481 asc_disable_tx_interrupts(port);
482 asc_disable_rx_interrupts(port);
483 free_irq(port->irq, port);
484}
485
486static void asc_pm(struct uart_port *port, unsigned int state,
487 unsigned int oldstate)
488{
489 struct asc_port *ascport = to_asc_port(port);
490 unsigned long flags = 0;
491 u32 ctl;
492
493 switch (state) {
494 case UART_PM_STATE_ON:
495 clk_prepare_enable(ascport->clk);
496 break;
497 case UART_PM_STATE_OFF:
498 /*
499 * Disable the ASC baud rate generator, which is as close as
500 * we can come to turning it off. Note this is not called with
501 * the port spinlock held.
502 */
503 spin_lock_irqsave(&port->lock, flags);
504 ctl = asc_in(port, ASC_CTL) & ~ASC_CTL_RUN;
505 asc_out(port, ASC_CTL, ctl);
506 spin_unlock_irqrestore(&port->lock, flags);
507 clk_disable_unprepare(ascport->clk);
508 break;
509 }
510}
511
512static void asc_set_termios(struct uart_port *port, struct ktermios *termios,
513 struct ktermios *old)
514{
515 struct asc_port *ascport = to_asc_port(port);
d7356256
LJ		 516 struct device_node *np = port->dev->of_node;
517 struct gpio_desc *gpiod;
c4b05856
SK		 518 unsigned int baud;
519 u32 ctrl_val;
520 tcflag_t cflag;
521 unsigned long flags;
522
523 /* Update termios to reflect hardware capabilities */
524 termios->c_cflag &= ~(CMSPAR |
525 (ascport->hw_flow_control ? 0 : CRTSCTS));
526
527 port->uartclk = clk_get_rate(ascport->clk);
528
529 baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
530 cflag = termios->c_cflag;
531
532 spin_lock_irqsave(&port->lock, flags);
533
534 /* read control register */
535 ctrl_val = asc_in(port, ASC_CTL);
536
537 /* stop serial port and reset value */
538 asc_out(port, ASC_CTL, (ctrl_val & ~ASC_CTL_RUN));
539 ctrl_val = ASC_CTL_RXENABLE | ASC_CTL_FIFOENABLE;
540
541 /* reset fifo rx & tx */
542 asc_out(port, ASC_TXRESET, 1);
543 asc_out(port, ASC_RXRESET, 1);
544
545 /* set character length */
546 if ((cflag & CSIZE) == CS7) {
547 ctrl_val |= ASC_CTL_MODE_7BIT_PAR;
548 } else {
549 ctrl_val |= (cflag & PARENB) ? ASC_CTL_MODE_8BIT_PAR :
550 ASC_CTL_MODE_8BIT;
551 }
552
553 /* set stop bit */
554 ctrl_val |= (cflag & CSTOPB) ? ASC_CTL_STOP_2BIT : ASC_CTL_STOP_1BIT;
555
556 /* odd parity */
557 if (cflag & PARODD)
558 ctrl_val |= ASC_CTL_PARITYODD;
559
560 /* hardware flow control */
d7356256 561 if ((cflag & CRTSCTS)) {
c4b05856
SK		 562 ctrl_val |= ASC_CTL_CTSENABLE;
563
d7356256
LJ		 564 /* If flow-control selected, stop handling RTS manually */
565 if (ascport->rts) {
566 devm_gpiod_put(port->dev, ascport->rts);
567 ascport->rts = NULL;
568
569 pinctrl_select_state(ascport->pinctrl,
570 ascport->states[DEFAULT]);
571 }
572 } else {
573 /* If flow-control disabled, it's safe to handle RTS manually */
574 if (!ascport->rts && ascport->states[NO_HW_FLOWCTRL]) {
575 pinctrl_select_state(ascport->pinctrl,
576 ascport->states[NO_HW_FLOWCTRL]);
577
0043c1df
LJ		 578 gpiod = devm_fwnode_get_gpiod_from_child(port->dev,
579 "rts",
580 &np->fwnode,
581 GPIOD_OUT_LOW,
582 np->name);
583 if (!IS_ERR(gpiod))
d7356256 584 ascport->rts = gpiod;
d7356256
LJ		 585 }
586 }
587
c4b05856
SK		 588 if ((baud < 19200) && !ascport->force_m1) {
589 asc_out(port, ASC_BAUDRATE, (port->uartclk / (16 * baud)));
590 } else {
591 /*
592 * MODE 1: recommended for high bit rates (above 19.2K)
593 *
594 * baudrate * 16 * 2^16
595 * ASCBaudRate = ------------------------
596 * inputclock
597 *
1d6ba284 598 * To keep maths inside 64bits, we divide inputclock by 16.
c4b05856 599 */
1d6ba284
MC		 600 u64 dividend = (u64)baud * (1 << 16);
601
602 do_div(dividend, port->uartclk / 16);
603 asc_out(port, ASC_BAUDRATE, dividend);
c4b05856
SK		 604 ctrl_val |= ASC_CTL_BAUDMODE;
605 }
606
607 uart_update_timeout(port, cflag, baud);
608
609 ascport->port.read_status_mask = ASC_RXBUF_DUMMY_OE;
610 if (termios->c_iflag & INPCK)
611 ascport->port.read_status_mask |= ASC_RXBUF_FE | ASC_RXBUF_PE;
ef8b9ddc 612 if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
c4b05856
SK		 613 ascport->port.read_status_mask |= ASC_RXBUF_DUMMY_BE;
614
615 /*
616 * Characters to ignore
617 */
618 ascport->port.ignore_status_mask = 0;
619 if (termios->c_iflag & IGNPAR)
620 ascport->port.ignore_status_mask |= ASC_RXBUF_FE | ASC_RXBUF_PE;
621 if (termios->c_iflag & IGNBRK) {
622 ascport->port.ignore_status_mask |= ASC_RXBUF_DUMMY_BE;
623 /*
624 * If we're ignoring parity and break indicators,
625 * ignore overruns too (for real raw support).
626 */
627 if (termios->c_iflag & IGNPAR)
628 ascport->port.ignore_status_mask |= ASC_RXBUF_DUMMY_OE;
629 }
630
631 /*
632 * Ignore all characters if CREAD is not set.
633 */
634 if (!(termios->c_cflag & CREAD))
635 ascport->port.ignore_status_mask |= ASC_RXBUF_DUMMY_RX;
636
637 /* Set the timeout */
638 asc_out(port, ASC_TIMEOUT, 20);
639
640 /* write final value and enable port */
641 asc_out(port, ASC_CTL, (ctrl_val | ASC_CTL_RUN));
642
643 spin_unlock_irqrestore(&port->lock, flags);
644}
645
646static const char *asc_type(struct uart_port *port)
647{
648 return (port->type == PORT_ASC) ? DRIVER_NAME : NULL;
649}
650
651static void asc_release_port(struct uart_port *port)
652{
653}
654
655static int asc_request_port(struct uart_port *port)
656{
657 return 0;
658}
659
660/*
661 * Called when the port is opened, and UPF_BOOT_AUTOCONF flag is set
662 * Set type field if successful
663 */
664static void asc_config_port(struct uart_port *port, int flags)
665{
666 if ((flags & UART_CONFIG_TYPE))
667 port->type = PORT_ASC;
668}
669
670static int
671asc_verify_port(struct uart_port *port, struct serial_struct *ser)
672{
673 /* No user changeable parameters */
674 return -EINVAL;
675}
676
677#ifdef CONFIG_CONSOLE_POLL
678/*
679 * Console polling routines for writing and reading from the uart while
680 * in an interrupt or debug context (i.e. kgdb).
681 */
682
683static int asc_get_poll_char(struct uart_port *port)
684{
685 if (!(asc_in(port, ASC_STA) & ASC_STA_RBF))
686 return NO_POLL_CHAR;
687
688 return asc_in(port, ASC_RXBUF);
689}
690
691static void asc_put_poll_char(struct uart_port *port, unsigned char c)
692{
1ffcd67d 693 while (!asc_txfifo_is_half_empty(port))
c4b05856
SK		 694 cpu_relax();
695 asc_out(port, ASC_TXBUF, c);
696}
697
698#endif /* CONFIG_CONSOLE_POLL */
699
700/*---------------------------------------------------------------------*/
701
eeb8bc1a 702static const struct uart_ops asc_uart_ops = {
c4b05856
SK		 703 .tx_empty = asc_tx_empty,
704 .set_mctrl = asc_set_mctrl,
705 .get_mctrl = asc_get_mctrl,
706 .start_tx = asc_start_tx,
707 .stop_tx = asc_stop_tx,
708 .stop_rx = asc_stop_rx,
c4b05856
SK		 709 .break_ctl = asc_break_ctl,
710 .startup = asc_startup,
711 .shutdown = asc_shutdown,
712 .set_termios = asc_set_termios,
713 .type = asc_type,
714 .release_port = asc_release_port,
715 .request_port = asc_request_port,
716 .config_port = asc_config_port,
717 .verify_port = asc_verify_port,
718 .pm = asc_pm,
719#ifdef CONFIG_CONSOLE_POLL
720 .poll_get_char = asc_get_poll_char,
721 .poll_put_char = asc_put_poll_char,
722#endif /* CONFIG_CONSOLE_POLL */
723};
724
725static int asc_init_port(struct asc_port *ascport,
726 struct platform_device *pdev)
727{
728 struct uart_port *port = &ascport->port;
3abeff77 729 struct resource *res;
6929cb00 730 int ret;
c4b05856
SK		 731
732 port->iotype = UPIO_MEM;
733 port->flags = UPF_BOOT_AUTOCONF;
734 port->ops = &asc_uart_ops;
735 port->fifosize = ASC_FIFO_SIZE;
736 port->dev = &pdev->dev;
c4b05856
SK		 737 port->irq = platform_get_irq(pdev, 0);
738
3abeff77
JL		 739 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
740 port->membase = devm_ioremap_resource(&pdev->dev, res);
741 if (IS_ERR(port->membase))
742 return PTR_ERR(port->membase);
743 port->mapbase = res->start;
c4b05856
SK		 744
745 spin_lock_init(&port->lock);
746
747 ascport->clk = devm_clk_get(&pdev->dev, NULL);
748
749 if (WARN_ON(IS_ERR(ascport->clk)))
750 return -EINVAL;
751 /* ensure that clk rate is correct by enabling the clk */
752 clk_prepare_enable(ascport->clk);
753 ascport->port.uartclk = clk_get_rate(ascport->clk);
754 WARN_ON(ascport->port.uartclk == 0);
755 clk_disable_unprepare(ascport->clk);
756
6929cb00
LJ		 757 ascport->pinctrl = devm_pinctrl_get(&pdev->dev);
758 if (IS_ERR(ascport->pinctrl)) {
759 ret = PTR_ERR(ascport->pinctrl);
760 dev_err(&pdev->dev, "Failed to get Pinctrl: %d\n", ret);
2b01bfae 761 return ret;
6929cb00
LJ		 762 }
763
764 ascport->states[DEFAULT] =
765 pinctrl_lookup_state(ascport->pinctrl, "default");
766 if (IS_ERR(ascport->states[DEFAULT])) {
767 ret = PTR_ERR(ascport->states[DEFAULT]);
768 dev_err(&pdev->dev,
769 "Failed to look up Pinctrl state 'default': %d\n", ret);
770 return ret;
771 }
772
773 /* "no-hw-flowctrl" state is optional */
774 ascport->states[NO_HW_FLOWCTRL] =
775 pinctrl_lookup_state(ascport->pinctrl, "no-hw-flowctrl");
776 if (IS_ERR(ascport->states[NO_HW_FLOWCTRL]))
777 ascport->states[NO_HW_FLOWCTRL] = NULL;
778
c4b05856
SK		 779 return 0;
780}
781
782static struct asc_port *asc_of_get_asc_port(struct platform_device *pdev)
783{
784 struct device_node *np = pdev->dev.of_node;
785 int id;
786
787 if (!np)
788 return NULL;
789
790 id = of_alias_get_id(np, ASC_SERIAL_NAME);
791
792 if (id < 0)
793 id = 0;
794
795 if (WARN_ON(id >= ASC_MAX_PORTS))
796 return NULL;
797
798 asc_ports[id].hw_flow_control = of_property_read_bool(np,
233680a2 799 "uart-has-rtscts");
c4b05856
SK		 800 asc_ports[id].force_m1 = of_property_read_bool(np, "st,force_m1");
801 asc_ports[id].port.line = id;
a4f6072f
LJ		 802 asc_ports[id].rts = NULL;
803
c4b05856
SK		 804 return &asc_ports[id];
805}
806
a4f2dc9e 807#ifdef CONFIG_OF
ed0bb232 808static const struct of_device_id asc_match[] = {
c4b05856
SK		 809 { .compatible = "st,asc", },
810 {},
811};
812
813MODULE_DEVICE_TABLE(of, asc_match);
a4f2dc9e 814#endif
c4b05856
SK		 815
816static int asc_serial_probe(struct platform_device *pdev)
817{
818 int ret;
819 struct asc_port *ascport;
820
821 ascport = asc_of_get_asc_port(pdev);
822 if (!ascport)
823 return -ENODEV;
824
825 ret = asc_init_port(ascport, pdev);
826 if (ret)
827 return ret;
828
829 ret = uart_add_one_port(&asc_uart_driver, &ascport->port);
830 if (ret)
831 return ret;
832
833 platform_set_drvdata(pdev, &ascport->port);
834
835 return 0;
836}
837
838static int asc_serial_remove(struct platform_device *pdev)
839{
840 struct uart_port *port = platform_get_drvdata(pdev);
841
c4b05856
SK		 842 return uart_remove_one_port(&asc_uart_driver, port);
843}
844
845#ifdef CONFIG_PM_SLEEP
846static int asc_serial_suspend(struct device *dev)
847{
848 struct platform_device *pdev = to_platform_device(dev);
849 struct uart_port *port = platform_get_drvdata(pdev);
850
851 return uart_suspend_port(&asc_uart_driver, port);
852}
853
854static int asc_serial_resume(struct device *dev)
855{
856 struct platform_device *pdev = to_platform_device(dev);
857 struct uart_port *port = platform_get_drvdata(pdev);
858
859 return uart_resume_port(&asc_uart_driver, port);
860}
861
862#endif /* CONFIG_PM_SLEEP */
863
864/*----------------------------------------------------------------------*/
865
866#ifdef CONFIG_SERIAL_ST_ASC_CONSOLE
867static void asc_console_putchar(struct uart_port *port, int ch)
868{
869 unsigned int timeout = 1000000;
870
871 /* Wait for upto 1 second in case flow control is stopping us. */
1ffcd67d 872 while (--timeout && !asc_txfifo_is_half_empty(port))
c4b05856
SK		 873 udelay(1);
874
875 asc_out(port, ASC_TXBUF, ch);
876}
877
878/*
879 * Print a string to the serial port trying not to disturb
880 * any possible real use of the port...
881 */
882
883static void asc_console_write(struct console *co, const char *s, unsigned count)
884{
885 struct uart_port *port = &asc_ports[co->index].port;
886 unsigned long flags;
887 unsigned long timeout = 1000000;
888 int locked = 1;
889 u32 intenable;
890
c4b05856
SK		 891 if (port->sysrq)
892 locked = 0; /* asc_interrupt has already claimed the lock */
893 else if (oops_in_progress)
ef49ffd8 894 locked = spin_trylock_irqsave(&port->lock, flags);
c4b05856 895 else
ef49ffd8 896 spin_lock_irqsave(&port->lock, flags);
c4b05856
SK		 897
898 /*
899 * Disable interrupts so we don't get the IRQ line bouncing
900 * up and down while interrupts are disabled.
901 */
902 intenable = asc_in(port, ASC_INTEN);
903 asc_out(port, ASC_INTEN, 0);
904 (void)asc_in(port, ASC_INTEN); /* Defeat bus write posting */
905
906 uart_console_write(port, s, count, asc_console_putchar);
907
908 while (--timeout && !asc_txfifo_is_empty(port))
909 udelay(1);
910
911 asc_out(port, ASC_INTEN, intenable);
912
913 if (locked)
ef49ffd8 914 spin_unlock_irqrestore(&port->lock, flags);
c4b05856
SK		 915}
916
917static int asc_console_setup(struct console *co, char *options)
918{
919 struct asc_port *ascport;
b5090cb4 920 int baud = 115200;
c4b05856
SK		 921 int bits = 8;
922 int parity = 'n';
923 int flow = 'n';
924
925 if (co->index >= ASC_MAX_PORTS)
926 return -ENODEV;
927
928 ascport = &asc_ports[co->index];
929
930 /*
931 * This driver does not support early console initialization
932 * (use ARM early printk support instead), so we only expect
933 * this to be called during the uart port registration when the
934 * driver gets probed and the port should be mapped at that point.
935 */
5b4e79ae
MC		 936 if (ascport->port.mapbase == 0 || ascport->port.membase == NULL)
937 return -ENXIO;
c4b05856
SK		 938
939 if (options)
940 uart_parse_options(options, &baud, &parity, &bits, &flow);
941
942 return uart_set_options(&ascport->port, co, baud, parity, bits, flow);
943}
944
945static struct console asc_console = {
946 .name = ASC_SERIAL_NAME,
947 .device = uart_console_device,
948 .write = asc_console_write,
949 .setup = asc_console_setup,
950 .flags = CON_PRINTBUFFER,
951 .index = -1,
952 .data = &asc_uart_driver,
953};
954
955#define ASC_SERIAL_CONSOLE (&asc_console)
956
957#else
958#define ASC_SERIAL_CONSOLE NULL
959#endif /* CONFIG_SERIAL_ST_ASC_CONSOLE */
960
961static struct uart_driver asc_uart_driver = {
962 .owner = THIS_MODULE,
963 .driver_name = DRIVER_NAME,
964 .dev_name = ASC_SERIAL_NAME,
965 .major = 0,
966 .minor = 0,
967 .nr = ASC_MAX_PORTS,
968 .cons = ASC_SERIAL_CONSOLE,
969};
970
971static const struct dev_pm_ops asc_serial_pm_ops = {
972 SET_SYSTEM_SLEEP_PM_OPS(asc_serial_suspend, asc_serial_resume)
973};
974
975static struct platform_driver asc_serial_driver = {
976 .probe = asc_serial_probe,
977 .remove = asc_serial_remove,
978 .driver = {
979 .name = DRIVER_NAME,
980 .pm = &asc_serial_pm_ops,
c4b05856
SK		 981 .of_match_table = of_match_ptr(asc_match),
982 },
983};
984
985static int __init asc_init(void)
986{
987 int ret;
06324664 988 static const char banner[] __initconst =
c4b05856
SK		 989 KERN_INFO "STMicroelectronics ASC driver initialized\n";
990
991 printk(banner);
992
993 ret = uart_register_driver(&asc_uart_driver);
994 if (ret)
995 return ret;
996
997 ret = platform_driver_register(&asc_serial_driver);
998 if (ret)
999 uart_unregister_driver(&asc_uart_driver);
1000
1001 return ret;
1002}
1003
1004static void __exit asc_exit(void)
1005{
1006 platform_driver_unregister(&asc_serial_driver);
1007 uart_unregister_driver(&asc_uart_driver);
1008}
1009
1010module_init(asc_init);
1011module_exit(asc_exit);
1012
1013MODULE_ALIAS("platform:" DRIVER_NAME);
1014MODULE_AUTHOR("STMicroelectronics (R&D) Limited");
1015MODULE_DESCRIPTION("STMicroelectronics ASC serial port driver");
1016MODULE_LICENSE("GPL");
Ubuntu Artful kernel mirror