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git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
1/*
2 * 8250-core based driver for the OMAP internal UART
3 *
4 * based on omap-serial.c, Copyright (C) 2010 Texas Instruments.
5 *
6 * Copyright (C) 2014 Sebastian Andrzej Siewior
7 *
8 */
9
10#include <linux/device.h>
11#include <linux/io.h>
12#include <linux/module.h>
13#include <linux/serial_8250.h>
14#include <linux/serial_reg.h>
15#include <linux/tty_flip.h>
16#include <linux/platform_device.h>
17#include <linux/slab.h>
18#include <linux/of.h>
19#include <linux/of_device.h>
20#include <linux/of_gpio.h>
21#include <linux/of_irq.h>
22#include <linux/delay.h>
23#include <linux/pm_runtime.h>
24#include <linux/console.h>
25#include <linux/pm_qos.h>
26#include <linux/pm_wakeirq.h>
27#include <linux/dma-mapping.h>
28
29#include "8250.h"
30
31#define DEFAULT_CLK_SPEED 48000000
32
33#define UART_ERRATA_i202_MDR1_ACCESS (1 << 0)
34#define OMAP_UART_WER_HAS_TX_WAKEUP (1 << 1)
35#define OMAP_DMA_TX_KICK (1 << 2)
36/*
37 * See Advisory 21 in AM437x errata SPRZ408B, updated April 2015.
38 * The same errata is applicable to AM335x and DRA7x processors too.
39 */
40#define UART_ERRATA_CLOCK_DISABLE (1 << 3)
41
42#define OMAP_UART_FCR_RX_TRIG 6
43#define OMAP_UART_FCR_TX_TRIG 4
44
45/* SCR register bitmasks */
46#define OMAP_UART_SCR_RX_TRIG_GRANU1_MASK (1 << 7)
47#define OMAP_UART_SCR_TX_TRIG_GRANU1_MASK (1 << 6)
48#define OMAP_UART_SCR_TX_EMPTY (1 << 3)
49#define OMAP_UART_SCR_DMAMODE_MASK (3 << 1)
50#define OMAP_UART_SCR_DMAMODE_1 (1 << 1)
51#define OMAP_UART_SCR_DMAMODE_CTL (1 << 0)
52
53/* MVR register bitmasks */
54#define OMAP_UART_MVR_SCHEME_SHIFT 30
55#define OMAP_UART_LEGACY_MVR_MAJ_MASK 0xf0
56#define OMAP_UART_LEGACY_MVR_MAJ_SHIFT 4
57#define OMAP_UART_LEGACY_MVR_MIN_MASK 0x0f
58#define OMAP_UART_MVR_MAJ_MASK 0x700
59#define OMAP_UART_MVR_MAJ_SHIFT 8
60#define OMAP_UART_MVR_MIN_MASK 0x3f
61
62/* SYSC register bitmasks */
63#define OMAP_UART_SYSC_SOFTRESET (1 << 1)
64
65/* SYSS register bitmasks */
66#define OMAP_UART_SYSS_RESETDONE (1 << 0)
67
68#define UART_TI752_TLR_TX 0
69#define UART_TI752_TLR_RX 4
70
71#define TRIGGER_TLR_MASK(x) ((x & 0x3c) >> 2)
72#define TRIGGER_FCR_MASK(x) (x & 3)
73
74/* Enable XON/XOFF flow control on output */
75#define OMAP_UART_SW_TX 0x08
76/* Enable XON/XOFF flow control on input */
77#define OMAP_UART_SW_RX 0x02
78
79#define OMAP_UART_WER_MOD_WKUP 0x7f
80#define OMAP_UART_TX_WAKEUP_EN (1 << 7)
81
82#define TX_TRIGGER 1
83#define RX_TRIGGER 48
84
85#define OMAP_UART_TCR_RESTORE(x) ((x / 4) << 4)
86#define OMAP_UART_TCR_HALT(x) ((x / 4) << 0)
87
88#define UART_BUILD_REVISION(x, y) (((x) << 8) | (y))
89
90#define OMAP_UART_REV_46 0x0406
91#define OMAP_UART_REV_52 0x0502
92#define OMAP_UART_REV_63 0x0603
93
94struct omap8250_priv {
95 int line;
96 u8 habit;
97 u8 mdr1;
98 u8 efr;
99 u8 scr;
100 u8 wer;
101 u8 xon;
102 u8 xoff;
103 u8 delayed_restore;
104 u16 quot;
105
106 bool is_suspending;
107 int wakeirq;
108 int wakeups_enabled;
109 u32 latency;
110 u32 calc_latency;
111 struct pm_qos_request pm_qos_request;
112 struct work_struct qos_work;
113 struct uart_8250_dma omap8250_dma;
114 spinlock_t rx_dma_lock;
115 bool rx_dma_broken;
116};
117
118static u32 uart_read(struct uart_8250_port *up, u32 reg)
119{
120 return readl(up->port.membase + (reg << up->port.regshift));
121}
122
123static void omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl)
124{
125 struct uart_8250_port *up = up_to_u8250p(port);
126 struct omap8250_priv *priv = up->port.private_data;
127 u8 lcr;
128
129 serial8250_do_set_mctrl(port, mctrl);
130
131 /*
132 * Turn off autoRTS if RTS is lowered and restore autoRTS setting
133 * if RTS is raised
134 */
135 lcr = serial_in(up, UART_LCR);
136 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
137 if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS))
138 priv->efr |= UART_EFR_RTS;
139 else
140 priv->efr &= ~UART_EFR_RTS;
141 serial_out(up, UART_EFR, priv->efr);
142 serial_out(up, UART_LCR, lcr);
143}
144
145/*
146 * Work Around for Errata i202 (2430, 3430, 3630, 4430 and 4460)
147 * The access to uart register after MDR1 Access
148 * causes UART to corrupt data.
149 *
150 * Need a delay =
151 * 5 L4 clock cycles + 5 UART functional clock cycle (@48MHz = ~0.2uS)
152 * give 10 times as much
153 */
154static void omap_8250_mdr1_errataset(struct uart_8250_port *up,
155 struct omap8250_priv *priv)
156{
157 u8 timeout = 255;
158 u8 old_mdr1;
159
160 old_mdr1 = serial_in(up, UART_OMAP_MDR1);
161 if (old_mdr1 == priv->mdr1)
162 return;
163
164 serial_out(up, UART_OMAP_MDR1, priv->mdr1);
165 udelay(2);
166 serial_out(up, UART_FCR, up->fcr | UART_FCR_CLEAR_XMIT |
167 UART_FCR_CLEAR_RCVR);
168 /*
169 * Wait for FIFO to empty: when empty, RX_FIFO_E bit is 0 and
170 * TX_FIFO_E bit is 1.
171 */
172 while (UART_LSR_THRE != (serial_in(up, UART_LSR) &
173 (UART_LSR_THRE | UART_LSR_DR))) {
174 timeout--;
175 if (!timeout) {
176 /* Should *never* happen. we warn and carry on */
177 dev_crit(up->port.dev, "Errata i202: timedout %x\n",
178 serial_in(up, UART_LSR));
179 break;
180 }
181 udelay(1);
182 }
183}
184
185static void omap_8250_get_divisor(struct uart_port *port, unsigned int baud,
186 struct omap8250_priv *priv)
187{
188 unsigned int uartclk = port->uartclk;
189 unsigned int div_13, div_16;
190 unsigned int abs_d13, abs_d16;
191
192 /*
193 * Old custom speed handling.
194 */
195 if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST) {
196 priv->quot = port->custom_divisor & 0xffff;
197 /*
198 * I assume that nobody is using this. But hey, if somebody
199 * would like to specify the divisor _and_ the mode then the
200 * driver is ready and waiting for it.
201 */
202 if (port->custom_divisor & (1 << 16))
203 priv->mdr1 = UART_OMAP_MDR1_13X_MODE;
204 else
205 priv->mdr1 = UART_OMAP_MDR1_16X_MODE;
206 return;
207 }
208 div_13 = DIV_ROUND_CLOSEST(uartclk, 13 * baud);
209 div_16 = DIV_ROUND_CLOSEST(uartclk, 16 * baud);
210
211 if (!div_13)
212 div_13 = 1;
213 if (!div_16)
214 div_16 = 1;
215
216 abs_d13 = abs(baud - uartclk / 13 / div_13);
217 abs_d16 = abs(baud - uartclk / 16 / div_16);
218
219 if (abs_d13 >= abs_d16) {
220 priv->mdr1 = UART_OMAP_MDR1_16X_MODE;
221 priv->quot = div_16;
222 } else {
223 priv->mdr1 = UART_OMAP_MDR1_13X_MODE;
224 priv->quot = div_13;
225 }
226}
227
228static void omap8250_update_scr(struct uart_8250_port *up,
229 struct omap8250_priv *priv)
230{
231 u8 old_scr;
232
233 old_scr = serial_in(up, UART_OMAP_SCR);
234 if (old_scr == priv->scr)
235 return;
236
237 /*
238 * The manual recommends not to enable the DMA mode selector in the SCR
239 * (instead of the FCR) register _and_ selecting the DMA mode as one
240 * register write because this may lead to malfunction.
241 */
242 if (priv->scr & OMAP_UART_SCR_DMAMODE_MASK)
243 serial_out(up, UART_OMAP_SCR,
244 priv->scr & ~OMAP_UART_SCR_DMAMODE_MASK);
245 serial_out(up, UART_OMAP_SCR, priv->scr);
246}
247
248static void omap8250_update_mdr1(struct uart_8250_port *up,
249 struct omap8250_priv *priv)
250{
251 if (priv->habit & UART_ERRATA_i202_MDR1_ACCESS)
252 omap_8250_mdr1_errataset(up, priv);
253 else
254 serial_out(up, UART_OMAP_MDR1, priv->mdr1);
255}
256
257static void omap8250_restore_regs(struct uart_8250_port *up)
258{
259 struct omap8250_priv *priv = up->port.private_data;
260 struct uart_8250_dma *dma = up->dma;
261
262 if (dma && dma->tx_running) {
263 /*
264 * TCSANOW requests the change to occur immediately however if
265 * we have a TX-DMA operation in progress then it has been
266 * observed that it might stall and never complete. Therefore we
267 * delay DMA completes to prevent this hang from happen.
268 */
269 priv->delayed_restore = 1;
270 return;
271 }
272
273 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
274 serial_out(up, UART_EFR, UART_EFR_ECB);
275
276 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
277 serial_out(up, UART_MCR, UART_MCR_TCRTLR);
278 serial_out(up, UART_FCR, up->fcr);
279
280 omap8250_update_scr(up, priv);
281
282 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
283
284 serial_out(up, UART_TI752_TCR, OMAP_UART_TCR_RESTORE(16) |
285 OMAP_UART_TCR_HALT(52));
286 serial_out(up, UART_TI752_TLR,
287 TRIGGER_TLR_MASK(TX_TRIGGER) << UART_TI752_TLR_TX |
288 TRIGGER_TLR_MASK(RX_TRIGGER) << UART_TI752_TLR_RX);
289
290 serial_out(up, UART_LCR, 0);
291
292 /* drop TCR + TLR access, we setup XON/XOFF later */
293 serial_out(up, UART_MCR, up->mcr);
294 serial_out(up, UART_IER, up->ier);
295
296 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
297 serial_dl_write(up, priv->quot);
298
299 serial_out(up, UART_EFR, priv->efr);
300
301 /* Configure flow control */
302 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
303 serial_out(up, UART_XON1, priv->xon);
304 serial_out(up, UART_XOFF1, priv->xoff);
305
306 serial_out(up, UART_LCR, up->lcr);
307
308 omap8250_update_mdr1(up, priv);
309
310 up->port.ops->set_mctrl(&up->port, up->port.mctrl);
311}
312
313/*
314 * OMAP can use "CLK / (16 or 13) / div" for baud rate. And then we have have
315 * some differences in how we want to handle flow control.
316 */
317static void omap_8250_set_termios(struct uart_port *port,
318 struct ktermios *termios,
319 struct ktermios *old)
320{
321 struct uart_8250_port *up =
322 container_of(port, struct uart_8250_port, port);
323 struct omap8250_priv *priv = up->port.private_data;
324 unsigned char cval = 0;
325 unsigned int baud;
326
327 switch (termios->c_cflag & CSIZE) {
328 case CS5:
329 cval = UART_LCR_WLEN5;
330 break;
331 case CS6:
332 cval = UART_LCR_WLEN6;
333 break;
334 case CS7:
335 cval = UART_LCR_WLEN7;
336 break;
337 default:
338 case CS8:
339 cval = UART_LCR_WLEN8;
340 break;
341 }
342
343 if (termios->c_cflag & CSTOPB)
344 cval |= UART_LCR_STOP;
345 if (termios->c_cflag & PARENB)
346 cval |= UART_LCR_PARITY;
347 if (!(termios->c_cflag & PARODD))
348 cval |= UART_LCR_EPAR;
349 if (termios->c_cflag & CMSPAR)
350 cval |= UART_LCR_SPAR;
351
352 /*
353 * Ask the core to calculate the divisor for us.
354 */
355 baud = uart_get_baud_rate(port, termios, old,
356 port->uartclk / 16 / 0xffff,
357 port->uartclk / 13);
358 omap_8250_get_divisor(port, baud, priv);
359
360 /*
361 * Ok, we're now changing the port state. Do it with
362 * interrupts disabled.
363 */
364 pm_runtime_get_sync(port->dev);
365 spin_lock_irq(&port->lock);
366
367 /*
368 * Update the per-port timeout.
369 */
370 uart_update_timeout(port, termios->c_cflag, baud);
371
372 up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
373 if (termios->c_iflag & INPCK)
374 up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE;
375 if (termios->c_iflag & (IGNBRK | PARMRK))
376 up->port.read_status_mask |= UART_LSR_BI;
377
378 /*
379 * Characters to ignore
380 */
381 up->port.ignore_status_mask = 0;
382 if (termios->c_iflag & IGNPAR)
383 up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
384 if (termios->c_iflag & IGNBRK) {
385 up->port.ignore_status_mask |= UART_LSR_BI;
386 /*
387 * If we're ignoring parity and break indicators,
388 * ignore overruns too (for real raw support).
389 */
390 if (termios->c_iflag & IGNPAR)
391 up->port.ignore_status_mask |= UART_LSR_OE;
392 }
393
394 /*
395 * ignore all characters if CREAD is not set
396 */
397 if ((termios->c_cflag & CREAD) == 0)
398 up->port.ignore_status_mask |= UART_LSR_DR;
399
400 /*
401 * Modem status interrupts
402 */
403 up->ier &= ~UART_IER_MSI;
404 if (UART_ENABLE_MS(&up->port, termios->c_cflag))
405 up->ier |= UART_IER_MSI;
406
407 up->lcr = cval;
408 /* Up to here it was mostly serial8250_do_set_termios() */
409
410 /*
411 * We enable TRIG_GRANU for RX and TX and additionaly we set
412 * SCR_TX_EMPTY bit. The result is the following:
413 * - RX_TRIGGER amount of bytes in the FIFO will cause an interrupt.
414 * - less than RX_TRIGGER number of bytes will also cause an interrupt
415 * once the UART decides that there no new bytes arriving.
416 * - Once THRE is enabled, the interrupt will be fired once the FIFO is
417 * empty - the trigger level is ignored here.
418 *
419 * Once DMA is enabled:
420 * - UART will assert the TX DMA line once there is room for TX_TRIGGER
421 * bytes in the TX FIFO. On each assert the DMA engine will move
422 * TX_TRIGGER bytes into the FIFO.
423 * - UART will assert the RX DMA line once there are RX_TRIGGER bytes in
424 * the FIFO and move RX_TRIGGER bytes.
425 * This is because threshold and trigger values are the same.
426 */
427 up->fcr = UART_FCR_ENABLE_FIFO;
428 up->fcr |= TRIGGER_FCR_MASK(TX_TRIGGER) << OMAP_UART_FCR_TX_TRIG;
429 up->fcr |= TRIGGER_FCR_MASK(RX_TRIGGER) << OMAP_UART_FCR_RX_TRIG;
430
431 priv->scr = OMAP_UART_SCR_RX_TRIG_GRANU1_MASK | OMAP_UART_SCR_TX_EMPTY |
432 OMAP_UART_SCR_TX_TRIG_GRANU1_MASK;
433
434 if (up->dma)
435 priv->scr |= OMAP_UART_SCR_DMAMODE_1 |
436 OMAP_UART_SCR_DMAMODE_CTL;
437
438 priv->xon = termios->c_cc[VSTART];
439 priv->xoff = termios->c_cc[VSTOP];
440
441 priv->efr = 0;
442 up->mcr &= ~(UART_MCR_RTS | UART_MCR_XONANY);
443 up->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS | UPSTAT_AUTOXOFF);
444
445 if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW) {
446 /* Enable AUTOCTS (autoRTS is enabled when RTS is raised) */
447 up->port.status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
448 priv->efr |= UART_EFR_CTS;
449 } else if (up->port.flags & UPF_SOFT_FLOW) {
450 /*
451 * OMAP rx s/w flow control is borked; the transmitter remains
452 * stuck off even if rx flow control is subsequently disabled
453 */
454
455 /*
456 * IXOFF Flag:
457 * Enable XON/XOFF flow control on output.
458 * Transmit XON1, XOFF1
459 */
460 if (termios->c_iflag & IXOFF) {
461 up->port.status |= UPSTAT_AUTOXOFF;
462 priv->efr |= OMAP_UART_SW_TX;
463 }
464 }
465 omap8250_restore_regs(up);
466
467 spin_unlock_irq(&up->port.lock);
468 pm_runtime_mark_last_busy(port->dev);
469 pm_runtime_put_autosuspend(port->dev);
470
471 /* calculate wakeup latency constraint */
472 priv->calc_latency = USEC_PER_SEC * 64 * 8 / baud;
473 priv->latency = priv->calc_latency;
474
475 schedule_work(&priv->qos_work);
476
477 /* Don't rewrite B0 */
478 if (tty_termios_baud_rate(termios))
479 tty_termios_encode_baud_rate(termios, baud, baud);
480}
481
482/* same as 8250 except that we may have extra flow bits set in EFR */
483static void omap_8250_pm(struct uart_port *port, unsigned int state,
484 unsigned int oldstate)
485{
486 struct uart_8250_port *up = up_to_u8250p(port);
487 u8 efr;
488
489 pm_runtime_get_sync(port->dev);
490 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
491 efr = serial_in(up, UART_EFR);
492 serial_out(up, UART_EFR, efr | UART_EFR_ECB);
493 serial_out(up, UART_LCR, 0);
494
495 serial_out(up, UART_IER, (state != 0) ? UART_IERX_SLEEP : 0);
496 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
497 serial_out(up, UART_EFR, efr);
498 serial_out(up, UART_LCR, 0);
499
500 pm_runtime_mark_last_busy(port->dev);
501 pm_runtime_put_autosuspend(port->dev);
502}
503
504static void omap_serial_fill_features_erratas(struct uart_8250_port *up,
505 struct omap8250_priv *priv)
506{
507 u32 mvr, scheme;
508 u16 revision, major, minor;
509
510 mvr = uart_read(up, UART_OMAP_MVER);
511
512 /* Check revision register scheme */
513 scheme = mvr >> OMAP_UART_MVR_SCHEME_SHIFT;
514
515 switch (scheme) {
516 case 0: /* Legacy Scheme: OMAP2/3 */
517 /* MINOR_REV[0:4], MAJOR_REV[4:7] */
518 major = (mvr & OMAP_UART_LEGACY_MVR_MAJ_MASK) >>
519 OMAP_UART_LEGACY_MVR_MAJ_SHIFT;
520 minor = (mvr & OMAP_UART_LEGACY_MVR_MIN_MASK);
521 break;
522 case 1:
523 /* New Scheme: OMAP4+ */
524 /* MINOR_REV[0:5], MAJOR_REV[8:10] */
525 major = (mvr & OMAP_UART_MVR_MAJ_MASK) >>
526 OMAP_UART_MVR_MAJ_SHIFT;
527 minor = (mvr & OMAP_UART_MVR_MIN_MASK);
528 break;
529 default:
530 dev_warn(up->port.dev,
531 "Unknown revision, defaulting to highest\n");
532 /* highest possible revision */
533 major = 0xff;
534 minor = 0xff;
535 }
536 /* normalize revision for the driver */
537 revision = UART_BUILD_REVISION(major, minor);
538
539 switch (revision) {
540 case OMAP_UART_REV_46:
541 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS;
542 break;
543 case OMAP_UART_REV_52:
544 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS |
545 OMAP_UART_WER_HAS_TX_WAKEUP;
546 break;
547 case OMAP_UART_REV_63:
548 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS |
549 OMAP_UART_WER_HAS_TX_WAKEUP;
550 break;
551 default:
552 break;
553 }
554}
555
556static void omap8250_uart_qos_work(struct work_struct *work)
557{
558 struct omap8250_priv *priv;
559
560 priv = container_of(work, struct omap8250_priv, qos_work);
561 pm_qos_update_request(&priv->pm_qos_request, priv->latency);
562}
563
564#ifdef CONFIG_SERIAL_8250_DMA
565static int omap_8250_dma_handle_irq(struct uart_port *port);
566#endif
567
568static irqreturn_t omap8250_irq(int irq, void *dev_id)
569{
570 struct uart_port *port = dev_id;
571 struct uart_8250_port *up = up_to_u8250p(port);
572 unsigned int iir;
573 int ret;
574
575#ifdef CONFIG_SERIAL_8250_DMA
576 if (up->dma) {
577 ret = omap_8250_dma_handle_irq(port);
578 return IRQ_RETVAL(ret);
579 }
580#endif
581
582 serial8250_rpm_get(up);
583 iir = serial_port_in(port, UART_IIR);
584 ret = serial8250_handle_irq(port, iir);
585 serial8250_rpm_put(up);
586
587 return IRQ_RETVAL(ret);
588}
589
590static int omap_8250_startup(struct uart_port *port)
591{
592 struct uart_8250_port *up = up_to_u8250p(port);
593 struct omap8250_priv *priv = port->private_data;
594 int ret;
595
596 if (priv->wakeirq) {
597 ret = dev_pm_set_dedicated_wake_irq(port->dev, priv->wakeirq);
598 if (ret)
599 return ret;
600 }
601
602 pm_runtime_get_sync(port->dev);
603
604 up->mcr = 0;
605 serial_out(up, UART_FCR, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
606
607 serial_out(up, UART_LCR, UART_LCR_WLEN8);
608
609 up->lsr_saved_flags = 0;
610 up->msr_saved_flags = 0;
611
612 if (up->dma) {
613 ret = serial8250_request_dma(up);
614 if (ret) {
615 dev_warn_ratelimited(port->dev,
616 "failed to request DMA\n");
617 up->dma = NULL;
618 }
619 }
620
621 ret = request_irq(port->irq, omap8250_irq, IRQF_SHARED,
622 dev_name(port->dev), port);
623 if (ret < 0)
624 goto err;
625
626 up->ier = UART_IER_RLSI | UART_IER_RDI;
627 serial_out(up, UART_IER, up->ier);
628
629#ifdef CONFIG_PM
630 up->capabilities |= UART_CAP_RPM;
631#endif
632
633 /* Enable module level wake up */
634 priv->wer = OMAP_UART_WER_MOD_WKUP;
635 if (priv->habit & OMAP_UART_WER_HAS_TX_WAKEUP)
636 priv->wer |= OMAP_UART_TX_WAKEUP_EN;
637 serial_out(up, UART_OMAP_WER, priv->wer);
638
639 if (up->dma)
640 up->dma->rx_dma(up, 0);
641
642 pm_runtime_mark_last_busy(port->dev);
643 pm_runtime_put_autosuspend(port->dev);
644 return 0;
645err:
646 pm_runtime_mark_last_busy(port->dev);
647 pm_runtime_put_autosuspend(port->dev);
648 dev_pm_clear_wake_irq(port->dev);
649 return ret;
650}
651
652static void omap_8250_shutdown(struct uart_port *port)
653{
654 struct uart_8250_port *up = up_to_u8250p(port);
655 struct omap8250_priv *priv = port->private_data;
656
657 flush_work(&priv->qos_work);
658 if (up->dma)
659 up->dma->rx_dma(up, UART_IIR_RX_TIMEOUT);
660
661 pm_runtime_get_sync(port->dev);
662
663 serial_out(up, UART_OMAP_WER, 0);
664
665 up->ier = 0;
666 serial_out(up, UART_IER, 0);
667
668 if (up->dma)
669 serial8250_release_dma(up);
670
671 /*
672 * Disable break condition and FIFOs
673 */
674 if (up->lcr & UART_LCR_SBC)
675 serial_out(up, UART_LCR, up->lcr & ~UART_LCR_SBC);
676 serial_out(up, UART_FCR, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
677
678 pm_runtime_mark_last_busy(port->dev);
679 pm_runtime_put_autosuspend(port->dev);
680 free_irq(port->irq, port);
681 dev_pm_clear_wake_irq(port->dev);
682}
683
684static void omap_8250_throttle(struct uart_port *port)
685{
686 unsigned long flags;
687 struct uart_8250_port *up =
688 container_of(port, struct uart_8250_port, port);
689
690 pm_runtime_get_sync(port->dev);
691
692 spin_lock_irqsave(&port->lock, flags);
693 up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
694 serial_out(up, UART_IER, up->ier);
695 spin_unlock_irqrestore(&port->lock, flags);
696
697 pm_runtime_mark_last_busy(port->dev);
698 pm_runtime_put_autosuspend(port->dev);
699}
700
701static void omap_8250_unthrottle(struct uart_port *port)
702{
703 unsigned long flags;
704 struct uart_8250_port *up =
705 container_of(port, struct uart_8250_port, port);
706
707 pm_runtime_get_sync(port->dev);
708
709 spin_lock_irqsave(&port->lock, flags);
710 up->ier |= UART_IER_RLSI | UART_IER_RDI;
711 serial_out(up, UART_IER, up->ier);
712 spin_unlock_irqrestore(&port->lock, flags);
713
714 pm_runtime_mark_last_busy(port->dev);
715 pm_runtime_put_autosuspend(port->dev);
716}
717
718#ifdef CONFIG_SERIAL_8250_DMA
719static int omap_8250_rx_dma(struct uart_8250_port *p, unsigned int iir);
720
721static void __dma_rx_do_complete(struct uart_8250_port *p, bool error)
722{
723 struct omap8250_priv *priv = p->port.private_data;
724 struct uart_8250_dma *dma = p->dma;
725 struct tty_port *tty_port = &p->port.state->port;
726 struct dma_tx_state state;
727 int count;
728 unsigned long flags;
729
730 dma_sync_single_for_cpu(dma->rxchan->device->dev, dma->rx_addr,
731 dma->rx_size, DMA_FROM_DEVICE);
732
733 spin_lock_irqsave(&priv->rx_dma_lock, flags);
734
735 if (!dma->rx_running)
736 goto unlock;
737
738 dma->rx_running = 0;
739 dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state);
740 dmaengine_terminate_all(dma->rxchan);
741
742 count = dma->rx_size - state.residue;
743
744 tty_insert_flip_string(tty_port, dma->rx_buf, count);
745 p->port.icount.rx += count;
746unlock:
747 spin_unlock_irqrestore(&priv->rx_dma_lock, flags);
748
749 if (!error)
750 omap_8250_rx_dma(p, 0);
751
752 tty_flip_buffer_push(tty_port);
753}
754
755static void __dma_rx_complete(void *param)
756{
757 __dma_rx_do_complete(param, false);
758}
759
760static void omap_8250_rx_dma_flush(struct uart_8250_port *p)
761{
762 struct omap8250_priv *priv = p->port.private_data;
763 struct uart_8250_dma *dma = p->dma;
764 unsigned long flags;
765 int ret;
766
767 spin_lock_irqsave(&priv->rx_dma_lock, flags);
768
769 if (!dma->rx_running) {
770 spin_unlock_irqrestore(&priv->rx_dma_lock, flags);
771 return;
772 }
773
774 ret = dmaengine_pause(dma->rxchan);
775 if (WARN_ON_ONCE(ret))
776 priv->rx_dma_broken = true;
777
778 spin_unlock_irqrestore(&priv->rx_dma_lock, flags);
779
780 __dma_rx_do_complete(p, true);
781}
782
783static int omap_8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
784{
785 struct omap8250_priv *priv = p->port.private_data;
786 struct uart_8250_dma *dma = p->dma;
787 int err = 0;
788 struct dma_async_tx_descriptor *desc;
789 unsigned long flags;
790
791 switch (iir & 0x3f) {
792 case UART_IIR_RLSI:
793 /* 8250_core handles errors and break interrupts */
794 omap_8250_rx_dma_flush(p);
795 return -EIO;
796 case UART_IIR_RX_TIMEOUT:
797 /*
798 * If RCVR FIFO trigger level was not reached, complete the
799 * transfer and let 8250_core copy the remaining data.
800 */
801 omap_8250_rx_dma_flush(p);
802 return -ETIMEDOUT;
803 case UART_IIR_RDI:
804 /*
805 * The OMAP UART is a special BEAST. If we receive RDI we _have_
806 * a DMA transfer programmed but it didn't work. One reason is
807 * that we were too slow and there were too many bytes in the
808 * FIFO, the UART counted wrong and never kicked the DMA engine
809 * to do anything. That means once we receive RDI on OMAP then
810 * the DMA won't do anything soon so we have to cancel the DMA
811 * transfer and purge the FIFO manually.
812 */
813 omap_8250_rx_dma_flush(p);
814 return -ETIMEDOUT;
815
816 default:
817 break;
818 }
819
820 if (priv->rx_dma_broken)
821 return -EINVAL;
822
823 spin_lock_irqsave(&priv->rx_dma_lock, flags);
824
825 if (dma->rx_running)
826 goto out;
827
828 desc = dmaengine_prep_slave_single(dma->rxchan, dma->rx_addr,
829 dma->rx_size, DMA_DEV_TO_MEM,
830 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
831 if (!desc) {
832 err = -EBUSY;
833 goto out;
834 }
835
836 dma->rx_running = 1;
837 desc->callback = __dma_rx_complete;
838 desc->callback_param = p;
839
840 dma->rx_cookie = dmaengine_submit(desc);
841
842 dma_sync_single_for_device(dma->rxchan->device->dev, dma->rx_addr,
843 dma->rx_size, DMA_FROM_DEVICE);
844
845 dma_async_issue_pending(dma->rxchan);
846out:
847 spin_unlock_irqrestore(&priv->rx_dma_lock, flags);
848 return err;
849}
850
851static int omap_8250_tx_dma(struct uart_8250_port *p);
852
853static void omap_8250_dma_tx_complete(void *param)
854{
855 struct uart_8250_port *p = param;
856 struct uart_8250_dma *dma = p->dma;
857 struct circ_buf *xmit = &p->port.state->xmit;
858 unsigned long flags;
859 bool en_thri = false;
860 struct omap8250_priv *priv = p->port.private_data;
861
862 dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr,
863 UART_XMIT_SIZE, DMA_TO_DEVICE);
864
865 spin_lock_irqsave(&p->port.lock, flags);
866
867 dma->tx_running = 0;
868
869 xmit->tail += dma->tx_size;
870 xmit->tail &= UART_XMIT_SIZE - 1;
871 p->port.icount.tx += dma->tx_size;
872
873 if (priv->delayed_restore) {
874 priv->delayed_restore = 0;
875 omap8250_restore_regs(p);
876 }
877
878 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
879 uart_write_wakeup(&p->port);
880
881 if (!uart_circ_empty(xmit) && !uart_tx_stopped(&p->port)) {
882 int ret;
883
884 ret = omap_8250_tx_dma(p);
885 if (ret)
886 en_thri = true;
887
888 } else if (p->capabilities & UART_CAP_RPM) {
889 en_thri = true;
890 }
891
892 if (en_thri) {
893 dma->tx_err = 1;
894 p->ier |= UART_IER_THRI;
895 serial_port_out(&p->port, UART_IER, p->ier);
896 }
897
898 spin_unlock_irqrestore(&p->port.lock, flags);
899}
900
901static int omap_8250_tx_dma(struct uart_8250_port *p)
902{
903 struct uart_8250_dma *dma = p->dma;
904 struct omap8250_priv *priv = p->port.private_data;
905 struct circ_buf *xmit = &p->port.state->xmit;
906 struct dma_async_tx_descriptor *desc;
907 unsigned int skip_byte = 0;
908 int ret;
909
910 if (dma->tx_running)
911 return 0;
912 if (uart_tx_stopped(&p->port) || uart_circ_empty(xmit)) {
913
914 /*
915 * Even if no data, we need to return an error for the two cases
916 * below so serial8250_tx_chars() is invoked and properly clears
917 * THRI and/or runtime suspend.
918 */
919 if (dma->tx_err || p->capabilities & UART_CAP_RPM) {
920 ret = -EBUSY;
921 goto err;
922 }
923 if (p->ier & UART_IER_THRI) {
924 p->ier &= ~UART_IER_THRI;
925 serial_out(p, UART_IER, p->ier);
926 }
927 return 0;
928 }
929
930 dma->tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
931 if (priv->habit & OMAP_DMA_TX_KICK) {
932 u8 tx_lvl;
933
934 /*
935 * We need to put the first byte into the FIFO in order to start
936 * the DMA transfer. For transfers smaller than four bytes we
937 * don't bother doing DMA at all. It seem not matter if there
938 * are still bytes in the FIFO from the last transfer (in case
939 * we got here directly from omap_8250_dma_tx_complete()). Bytes
940 * leaving the FIFO seem not to trigger the DMA transfer. It is
941 * really the byte that we put into the FIFO.
942 * If the FIFO is already full then we most likely got here from
943 * omap_8250_dma_tx_complete(). And this means the DMA engine
944 * just completed its work. We don't have to wait the complete
945 * 86us at 115200,8n1 but around 60us (not to mention lower
946 * baudrates). So in that case we take the interrupt and try
947 * again with an empty FIFO.
948 */
949 tx_lvl = serial_in(p, UART_OMAP_TX_LVL);
950 if (tx_lvl == p->tx_loadsz) {
951 ret = -EBUSY;
952 goto err;
953 }
954 if (dma->tx_size < 4) {
955 ret = -EINVAL;
956 goto err;
957 }
958 skip_byte = 1;
959 }
960
961 desc = dmaengine_prep_slave_single(dma->txchan,
962 dma->tx_addr + xmit->tail + skip_byte,
963 dma->tx_size - skip_byte, DMA_MEM_TO_DEV,
964 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
965 if (!desc) {
966 ret = -EBUSY;
967 goto err;
968 }
969
970 dma->tx_running = 1;
971
972 desc->callback = omap_8250_dma_tx_complete;
973 desc->callback_param = p;
974
975 dma->tx_cookie = dmaengine_submit(desc);
976
977 dma_sync_single_for_device(dma->txchan->device->dev, dma->tx_addr,
978 UART_XMIT_SIZE, DMA_TO_DEVICE);
979
980 dma_async_issue_pending(dma->txchan);
981 if (dma->tx_err)
982 dma->tx_err = 0;
983
984 if (p->ier & UART_IER_THRI) {
985 p->ier &= ~UART_IER_THRI;
986 serial_out(p, UART_IER, p->ier);
987 }
988 if (skip_byte)
989 serial_out(p, UART_TX, xmit->buf[xmit->tail]);
990 return 0;
991err:
992 dma->tx_err = 1;
993 return ret;
994}
995
996/*
997 * This is mostly serial8250_handle_irq(). We have a slightly different DMA
998 * hoook for RX/TX and need different logic for them in the ISR. Therefore we
999 * use the default routine in the non-DMA case and this one for with DMA.
1000 */
1001static int omap_8250_dma_handle_irq(struct uart_port *port)
1002{
1003 struct uart_8250_port *up = up_to_u8250p(port);
1004 unsigned char status;
1005 unsigned long flags;
1006 u8 iir;
1007 int dma_err = 0;
1008
1009 serial8250_rpm_get(up);
1010
1011 iir = serial_port_in(port, UART_IIR);
1012 if (iir & UART_IIR_NO_INT) {
1013 serial8250_rpm_put(up);
1014 return 0;
1015 }
1016
1017 spin_lock_irqsave(&port->lock, flags);
1018
1019 status = serial_port_in(port, UART_LSR);
1020
1021 if (status & (UART_LSR_DR | UART_LSR_BI)) {
1022
1023 dma_err = omap_8250_rx_dma(up, iir);
1024 if (dma_err) {
1025 status = serial8250_rx_chars(up, status);
1026 omap_8250_rx_dma(up, 0);
1027 }
1028 }
1029 serial8250_modem_status(up);
1030 if (status & UART_LSR_THRE && up->dma->tx_err) {
1031 if (uart_tx_stopped(&up->port) ||
1032 uart_circ_empty(&up->port.state->xmit)) {
1033 up->dma->tx_err = 0;
1034 serial8250_tx_chars(up);
1035 } else {
1036 /*
1037 * try again due to an earlier failer which
1038 * might have been resolved by now.
1039 */
1040 dma_err = omap_8250_tx_dma(up);
1041 if (dma_err)
1042 serial8250_tx_chars(up);
1043 }
1044 }
1045
1046 spin_unlock_irqrestore(&port->lock, flags);
1047 serial8250_rpm_put(up);
1048 return 1;
1049}
1050
1051static bool the_no_dma_filter_fn(struct dma_chan *chan, void *param)
1052{
1053 return false;
1054}
1055
1056#else
1057
1058static inline int omap_8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
1059{
1060 return -EINVAL;
1061}
1062#endif
1063
1064static int omap8250_no_handle_irq(struct uart_port *port)
1065{
1066 /* IRQ has not been requested but handling irq? */
1067 WARN_ONCE(1, "Unexpected irq handling before port startup\n");
1068 return 0;
1069}
1070
1071static const u8 am3352_habit = OMAP_DMA_TX_KICK | UART_ERRATA_CLOCK_DISABLE;
1072static const u8 am4372_habit = UART_ERRATA_CLOCK_DISABLE;
1073
1074static const struct of_device_id omap8250_dt_ids[] = {
1075 { .compatible = "ti,omap2-uart" },
1076 { .compatible = "ti,omap3-uart" },
1077 { .compatible = "ti,omap4-uart" },
1078 { .compatible = "ti,am3352-uart", .data = &am3352_habit, },
1079 { .compatible = "ti,am4372-uart", .data = &am4372_habit, },
1080 { .compatible = "ti,dra742-uart", .data = &am4372_habit, },
1081 {},
1082};
1083MODULE_DEVICE_TABLE(of, omap8250_dt_ids);
1084
1085static int omap8250_probe(struct platform_device *pdev)
1086{
1087 struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1088 struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
1089 struct omap8250_priv *priv;
1090 struct uart_8250_port up;
1091 int ret;
1092 void __iomem *membase;
1093
1094 if (!regs || !irq) {
1095 dev_err(&pdev->dev, "missing registers or irq\n");
1096 return -EINVAL;
1097 }
1098
1099 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
1100 if (!priv)
1101 return -ENOMEM;
1102
1103 membase = devm_ioremap_nocache(&pdev->dev, regs->start,
1104 resource_size(regs));
1105 if (!membase)
1106 return -ENODEV;
1107
1108 memset(&up, 0, sizeof(up));
1109 up.port.dev = &pdev->dev;
1110 up.port.mapbase = regs->start;
1111 up.port.membase = membase;
1112 up.port.irq = irq->start;
1113 /*
1114 * It claims to be 16C750 compatible however it is a little different.
1115 * It has EFR and has no FCR7_64byte bit. The AFE (which it claims to
1116 * have) is enabled via EFR instead of MCR. The type is set here 8250
1117 * just to get things going. UNKNOWN does not work for a few reasons and
1118 * we don't need our own type since we don't use 8250's set_termios()
1119 * or pm callback.
1120 */
1121 up.port.type = PORT_8250;
1122 up.port.iotype = UPIO_MEM;
1123 up.port.flags = UPF_FIXED_PORT | UPF_FIXED_TYPE | UPF_SOFT_FLOW |
1124 UPF_HARD_FLOW;
1125 up.port.private_data = priv;
1126
1127 up.port.regshift = 2;
1128 up.port.fifosize = 64;
1129 up.tx_loadsz = 64;
1130 up.capabilities = UART_CAP_FIFO;
1131#ifdef CONFIG_PM
1132 /*
1133 * Runtime PM is mostly transparent. However to do it right we need to a
1134 * TX empty interrupt before we can put the device to auto idle. So if
1135 * PM is not enabled we don't add that flag and can spare that one extra
1136 * interrupt in the TX path.
1137 */
1138 up.capabilities |= UART_CAP_RPM;
1139#endif
1140 up.port.set_termios = omap_8250_set_termios;
1141 up.port.set_mctrl = omap8250_set_mctrl;
1142 up.port.pm = omap_8250_pm;
1143 up.port.startup = omap_8250_startup;
1144 up.port.shutdown = omap_8250_shutdown;
1145 up.port.throttle = omap_8250_throttle;
1146 up.port.unthrottle = omap_8250_unthrottle;
1147
1148 if (pdev->dev.of_node) {
1149 const struct of_device_id *id;
1150
1151 ret = of_alias_get_id(pdev->dev.of_node, "serial");
1152
1153 of_property_read_u32(pdev->dev.of_node, "clock-frequency",
1154 &up.port.uartclk);
1155 priv->wakeirq = irq_of_parse_and_map(pdev->dev.of_node, 1);
1156
1157 id = of_match_device(of_match_ptr(omap8250_dt_ids), &pdev->dev);
1158 if (id && id->data)
1159 priv->habit |= *(u8 *)id->data;
1160 } else {
1161 ret = pdev->id;
1162 }
1163 if (ret < 0) {
1164 dev_err(&pdev->dev, "failed to get alias/pdev id\n");
1165 return ret;
1166 }
1167 up.port.line = ret;
1168
1169 if (!up.port.uartclk) {
1170 up.port.uartclk = DEFAULT_CLK_SPEED;
1171 dev_warn(&pdev->dev,
1172 "No clock speed specified: using default: %d\n",
1173 DEFAULT_CLK_SPEED);
1174 }
1175
1176 priv->latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;
1177 priv->calc_latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;
1178 pm_qos_add_request(&priv->pm_qos_request, PM_QOS_CPU_DMA_LATENCY,
1179 priv->latency);
1180 INIT_WORK(&priv->qos_work, omap8250_uart_qos_work);
1181
1182 spin_lock_init(&priv->rx_dma_lock);
1183
1184 device_init_wakeup(&pdev->dev, true);
1185 pm_runtime_use_autosuspend(&pdev->dev);
1186 pm_runtime_set_autosuspend_delay(&pdev->dev, -1);
1187
1188 pm_runtime_irq_safe(&pdev->dev);
1189 pm_runtime_enable(&pdev->dev);
1190
1191 pm_runtime_get_sync(&pdev->dev);
1192
1193 omap_serial_fill_features_erratas(&up, priv);
1194 up.port.handle_irq = omap8250_no_handle_irq;
1195#ifdef CONFIG_SERIAL_8250_DMA
1196 if (pdev->dev.of_node) {
1197 /*
1198 * Oh DMA support. If there are no DMA properties in the DT then
1199 * we will fall back to a generic DMA channel which does not
1200 * really work here. To ensure that we do not get a generic DMA
1201 * channel assigned, we have the the_no_dma_filter_fn() here.
1202 * To avoid "failed to request DMA" messages we check for DMA
1203 * properties in DT.
1204 */
1205 ret = of_property_count_strings(pdev->dev.of_node, "dma-names");
1206 if (ret == 2) {
1207 up.dma = &priv->omap8250_dma;
1208 priv->omap8250_dma.fn = the_no_dma_filter_fn;
1209 priv->omap8250_dma.tx_dma = omap_8250_tx_dma;
1210 priv->omap8250_dma.rx_dma = omap_8250_rx_dma;
1211 priv->omap8250_dma.rx_size = RX_TRIGGER;
1212 priv->omap8250_dma.rxconf.src_maxburst = RX_TRIGGER;
1213 priv->omap8250_dma.txconf.dst_maxburst = TX_TRIGGER;
1214
1215 if (of_machine_is_compatible("ti,am33xx"))
1216 priv->habit |= OMAP_DMA_TX_KICK;
1217 /*
1218 * pause is currently not supported atleast on omap-sdma
1219 * and edma on most earlier kernels.
1220 */
1221 priv->rx_dma_broken = true;
1222 }
1223 }
1224#endif
1225 ret = serial8250_register_8250_port(&up);
1226 if (ret < 0) {
1227 dev_err(&pdev->dev, "unable to register 8250 port\n");
1228 goto err;
1229 }
1230 priv->line = ret;
1231 platform_set_drvdata(pdev, priv);
1232 pm_runtime_mark_last_busy(&pdev->dev);
1233 pm_runtime_put_autosuspend(&pdev->dev);
1234 return 0;
1235err:
1236 pm_runtime_put(&pdev->dev);
1237 pm_runtime_disable(&pdev->dev);
1238 return ret;
1239}
1240
1241static int omap8250_remove(struct platform_device *pdev)
1242{
1243 struct omap8250_priv *priv = platform_get_drvdata(pdev);
1244
1245 pm_runtime_put_sync(&pdev->dev);
1246 pm_runtime_disable(&pdev->dev);
1247 serial8250_unregister_port(priv->line);
1248 pm_qos_remove_request(&priv->pm_qos_request);
1249 device_init_wakeup(&pdev->dev, false);
1250 return 0;
1251}
1252
1253#ifdef CONFIG_PM_SLEEP
1254static int omap8250_prepare(struct device *dev)
1255{
1256 struct omap8250_priv *priv = dev_get_drvdata(dev);
1257
1258 if (!priv)
1259 return 0;
1260 priv->is_suspending = true;
1261 return 0;
1262}
1263
1264static void omap8250_complete(struct device *dev)
1265{
1266 struct omap8250_priv *priv = dev_get_drvdata(dev);
1267
1268 if (!priv)
1269 return;
1270 priv->is_suspending = false;
1271}
1272
1273static int omap8250_suspend(struct device *dev)
1274{
1275 struct omap8250_priv *priv = dev_get_drvdata(dev);
1276
1277 serial8250_suspend_port(priv->line);
1278 flush_work(&priv->qos_work);
1279 return 0;
1280}
1281
1282static int omap8250_resume(struct device *dev)
1283{
1284 struct omap8250_priv *priv = dev_get_drvdata(dev);
1285
1286 serial8250_resume_port(priv->line);
1287 return 0;
1288}
1289#else
1290#define omap8250_prepare NULL
1291#define omap8250_complete NULL
1292#endif
1293
1294#ifdef CONFIG_PM
1295static int omap8250_lost_context(struct uart_8250_port *up)
1296{
1297 u32 val;
1298
1299 val = serial_in(up, UART_OMAP_SCR);
1300 /*
1301 * If we lose context, then SCR is set to its reset value of zero.
1302 * After set_termios() we set bit 3 of SCR (TX_EMPTY_CTL_IT) to 1,
1303 * among other bits, to never set the register back to zero again.
1304 */
1305 if (!val)
1306 return 1;
1307 return 0;
1308}
1309
1310/* TODO: in future, this should happen via API in drivers/reset/ */
1311static int omap8250_soft_reset(struct device *dev)
1312{
1313 struct omap8250_priv *priv = dev_get_drvdata(dev);
1314 struct uart_8250_port *up = serial8250_get_port(priv->line);
1315 int timeout = 100;
1316 int sysc;
1317 int syss;
1318
1319 sysc = serial_in(up, UART_OMAP_SYSC);
1320
1321 /* softreset the UART */
1322 sysc |= OMAP_UART_SYSC_SOFTRESET;
1323 serial_out(up, UART_OMAP_SYSC, sysc);
1324
1325 /* By experiments, 1us enough for reset complete on AM335x */
1326 do {
1327 udelay(1);
1328 syss = serial_in(up, UART_OMAP_SYSS);
1329 } while (--timeout && !(syss & OMAP_UART_SYSS_RESETDONE));
1330
1331 if (!timeout) {
1332 dev_err(dev, "timed out waiting for reset done\n");
1333 return -ETIMEDOUT;
1334 }
1335
1336 return 0;
1337}
1338
1339static int omap8250_runtime_suspend(struct device *dev)
1340{
1341 struct omap8250_priv *priv = dev_get_drvdata(dev);
1342 struct uart_8250_port *up;
1343
1344 up = serial8250_get_port(priv->line);
1345 /*
1346 * When using 'no_console_suspend', the console UART must not be
1347 * suspended. Since driver suspend is managed by runtime suspend,
1348 * preventing runtime suspend (by returning error) will keep device
1349 * active during suspend.
1350 */
1351 if (priv->is_suspending && !console_suspend_enabled) {
1352 if (uart_console(&up->port))
1353 return -EBUSY;
1354 }
1355
1356 if (priv->habit & UART_ERRATA_CLOCK_DISABLE) {
1357 int ret;
1358
1359 ret = omap8250_soft_reset(dev);
1360 if (ret)
1361 return ret;
1362
1363 /* Restore to UART mode after reset (for wakeup) */
1364 omap8250_update_mdr1(up, priv);
1365 }
1366
1367 if (up->dma && up->dma->rxchan)
1368 omap_8250_rx_dma(up, UART_IIR_RX_TIMEOUT);
1369
1370 priv->latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;
1371 schedule_work(&priv->qos_work);
1372
1373 return 0;
1374}
1375
1376static int omap8250_runtime_resume(struct device *dev)
1377{
1378 struct omap8250_priv *priv = dev_get_drvdata(dev);
1379 struct uart_8250_port *up;
1380 int loss_cntx;
1381
1382 /* In case runtime-pm tries this before we are setup */
1383 if (!priv)
1384 return 0;
1385
1386 up = serial8250_get_port(priv->line);
1387 loss_cntx = omap8250_lost_context(up);
1388
1389 if (loss_cntx)
1390 omap8250_restore_regs(up);
1391
1392 if (up->dma && up->dma->rxchan)
1393 omap_8250_rx_dma(up, 0);
1394
1395 priv->latency = priv->calc_latency;
1396 schedule_work(&priv->qos_work);
1397 return 0;
1398}
1399#endif
1400
1401#ifdef CONFIG_SERIAL_8250_OMAP_TTYO_FIXUP
1402static int __init omap8250_console_fixup(void)
1403{
1404 char *omap_str;
1405 char *options;
1406 u8 idx;
1407
1408 if (strstr(boot_command_line, "console=ttyS"))
1409 /* user set a ttyS based name for the console */
1410 return 0;
1411
1412 omap_str = strstr(boot_command_line, "console=ttyO");
1413 if (!omap_str)
1414 /* user did not set ttyO based console, so we don't care */
1415 return 0;
1416
1417 omap_str += 12;
1418 if ('0' <= *omap_str && *omap_str <= '9')
1419 idx = *omap_str - '0';
1420 else
1421 return 0;
1422
1423 omap_str++;
1424 if (omap_str[0] == ',') {
1425 omap_str++;
1426 options = omap_str;
1427 } else {
1428 options = NULL;
1429 }
1430
1431 add_preferred_console("ttyS", idx, options);
1432 pr_err("WARNING: Your 'console=ttyO%d' has been replaced by 'ttyS%d'\n",
1433 idx, idx);
1434 pr_err("This ensures that you still see kernel messages. Please\n");
1435 pr_err("update your kernel commandline.\n");
1436 return 0;
1437}
1438console_initcall(omap8250_console_fixup);
1439#endif
1440
1441static const struct dev_pm_ops omap8250_dev_pm_ops = {
1442 SET_SYSTEM_SLEEP_PM_OPS(omap8250_suspend, omap8250_resume)
1443 SET_RUNTIME_PM_OPS(omap8250_runtime_suspend,
1444 omap8250_runtime_resume, NULL)
1445 .prepare = omap8250_prepare,
1446 .complete = omap8250_complete,
1447};
1448
1449static struct platform_driver omap8250_platform_driver = {
1450 .driver = {
1451 .name = "omap8250",
1452 .pm = &omap8250_dev_pm_ops,
1453 .of_match_table = omap8250_dt_ids,
1454 },
1455 .probe = omap8250_probe,
1456 .remove = omap8250_remove,
1457};
1458module_platform_driver(omap8250_platform_driver);
1459
1460MODULE_AUTHOR("Sebastian Andrzej Siewior");
1461MODULE_DESCRIPTION("OMAP 8250 Driver");
1462MODULE_LICENSE("GPL v2");