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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
94 struct 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
118 #ifdef CONFIG_SERIAL_8250_DMA
119 static void omap_8250_rx_dma_flush(struct uart_8250_port *p);
120 #else
121 static inline void omap_8250_rx_dma_flush(struct uart_8250_port *p) { }
122 #endif
123
124 static u32 uart_read(struct uart_8250_port *up, u32 reg)
125 {
126 return readl(up->port.membase + (reg << up->port.regshift));
127 }
128
129 static void omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl)
130 {
131 struct uart_8250_port *up = up_to_u8250p(port);
132 struct omap8250_priv *priv = up->port.private_data;
133 u8 lcr;
134
135 serial8250_do_set_mctrl(port, mctrl);
136
137 /*
138 * Turn off autoRTS if RTS is lowered and restore autoRTS setting
139 * if RTS is raised
140 */
141 lcr = serial_in(up, UART_LCR);
142 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
143 if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS))
144 priv->efr |= UART_EFR_RTS;
145 else
146 priv->efr &= ~UART_EFR_RTS;
147 serial_out(up, UART_EFR, priv->efr);
148 serial_out(up, UART_LCR, lcr);
149 }
150
151 /*
152 * Work Around for Errata i202 (2430, 3430, 3630, 4430 and 4460)
153 * The access to uart register after MDR1 Access
154 * causes UART to corrupt data.
155 *
156 * Need a delay =
157 * 5 L4 clock cycles + 5 UART functional clock cycle (@48MHz = ~0.2uS)
158 * give 10 times as much
159 */
160 static void omap_8250_mdr1_errataset(struct uart_8250_port *up,
161 struct omap8250_priv *priv)
162 {
163 u8 timeout = 255;
164 u8 old_mdr1;
165
166 old_mdr1 = serial_in(up, UART_OMAP_MDR1);
167 if (old_mdr1 == priv->mdr1)
168 return;
169
170 serial_out(up, UART_OMAP_MDR1, priv->mdr1);
171 udelay(2);
172 serial_out(up, UART_FCR, up->fcr | UART_FCR_CLEAR_XMIT |
173 UART_FCR_CLEAR_RCVR);
174 /*
175 * Wait for FIFO to empty: when empty, RX_FIFO_E bit is 0 and
176 * TX_FIFO_E bit is 1.
177 */
178 while (UART_LSR_THRE != (serial_in(up, UART_LSR) &
179 (UART_LSR_THRE | UART_LSR_DR))) {
180 timeout--;
181 if (!timeout) {
182 /* Should *never* happen. we warn and carry on */
183 dev_crit(up->port.dev, "Errata i202: timedout %x\n",
184 serial_in(up, UART_LSR));
185 break;
186 }
187 udelay(1);
188 }
189 }
190
191 static void omap_8250_get_divisor(struct uart_port *port, unsigned int baud,
192 struct omap8250_priv *priv)
193 {
194 unsigned int uartclk = port->uartclk;
195 unsigned int div_13, div_16;
196 unsigned int abs_d13, abs_d16;
197
198 /*
199 * Old custom speed handling.
200 */
201 if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST) {
202 priv->quot = port->custom_divisor & 0xffff;
203 /*
204 * I assume that nobody is using this. But hey, if somebody
205 * would like to specify the divisor _and_ the mode then the
206 * driver is ready and waiting for it.
207 */
208 if (port->custom_divisor & (1 << 16))
209 priv->mdr1 = UART_OMAP_MDR1_13X_MODE;
210 else
211 priv->mdr1 = UART_OMAP_MDR1_16X_MODE;
212 return;
213 }
214 div_13 = DIV_ROUND_CLOSEST(uartclk, 13 * baud);
215 div_16 = DIV_ROUND_CLOSEST(uartclk, 16 * baud);
216
217 if (!div_13)
218 div_13 = 1;
219 if (!div_16)
220 div_16 = 1;
221
222 abs_d13 = abs(baud - uartclk / 13 / div_13);
223 abs_d16 = abs(baud - uartclk / 16 / div_16);
224
225 if (abs_d13 >= abs_d16) {
226 priv->mdr1 = UART_OMAP_MDR1_16X_MODE;
227 priv->quot = div_16;
228 } else {
229 priv->mdr1 = UART_OMAP_MDR1_13X_MODE;
230 priv->quot = div_13;
231 }
232 }
233
234 static void omap8250_update_scr(struct uart_8250_port *up,
235 struct omap8250_priv *priv)
236 {
237 u8 old_scr;
238
239 old_scr = serial_in(up, UART_OMAP_SCR);
240 if (old_scr == priv->scr)
241 return;
242
243 /*
244 * The manual recommends not to enable the DMA mode selector in the SCR
245 * (instead of the FCR) register _and_ selecting the DMA mode as one
246 * register write because this may lead to malfunction.
247 */
248 if (priv->scr & OMAP_UART_SCR_DMAMODE_MASK)
249 serial_out(up, UART_OMAP_SCR,
250 priv->scr & ~OMAP_UART_SCR_DMAMODE_MASK);
251 serial_out(up, UART_OMAP_SCR, priv->scr);
252 }
253
254 static void omap8250_update_mdr1(struct uart_8250_port *up,
255 struct omap8250_priv *priv)
256 {
257 if (priv->habit & UART_ERRATA_i202_MDR1_ACCESS)
258 omap_8250_mdr1_errataset(up, priv);
259 else
260 serial_out(up, UART_OMAP_MDR1, priv->mdr1);
261 }
262
263 static void omap8250_restore_regs(struct uart_8250_port *up)
264 {
265 struct omap8250_priv *priv = up->port.private_data;
266 struct uart_8250_dma *dma = up->dma;
267
268 if (dma && dma->tx_running) {
269 /*
270 * TCSANOW requests the change to occur immediately however if
271 * we have a TX-DMA operation in progress then it has been
272 * observed that it might stall and never complete. Therefore we
273 * delay DMA completes to prevent this hang from happen.
274 */
275 priv->delayed_restore = 1;
276 return;
277 }
278
279 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
280 serial_out(up, UART_EFR, UART_EFR_ECB);
281
282 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
283 serial8250_out_MCR(up, UART_MCR_TCRTLR);
284 serial_out(up, UART_FCR, up->fcr);
285
286 omap8250_update_scr(up, priv);
287
288 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
289
290 serial_out(up, UART_TI752_TCR, OMAP_UART_TCR_RESTORE(16) |
291 OMAP_UART_TCR_HALT(52));
292 serial_out(up, UART_TI752_TLR,
293 TRIGGER_TLR_MASK(TX_TRIGGER) << UART_TI752_TLR_TX |
294 TRIGGER_TLR_MASK(RX_TRIGGER) << UART_TI752_TLR_RX);
295
296 serial_out(up, UART_LCR, 0);
297
298 /* drop TCR + TLR access, we setup XON/XOFF later */
299 serial8250_out_MCR(up, up->mcr);
300 serial_out(up, UART_IER, up->ier);
301
302 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
303 serial_dl_write(up, priv->quot);
304
305 serial_out(up, UART_EFR, priv->efr);
306
307 /* Configure flow control */
308 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
309 serial_out(up, UART_XON1, priv->xon);
310 serial_out(up, UART_XOFF1, priv->xoff);
311
312 serial_out(up, UART_LCR, up->lcr);
313
314 omap8250_update_mdr1(up, priv);
315
316 up->port.ops->set_mctrl(&up->port, up->port.mctrl);
317 }
318
319 /*
320 * OMAP can use "CLK / (16 or 13) / div" for baud rate. And then we have have
321 * some differences in how we want to handle flow control.
322 */
323 static void omap_8250_set_termios(struct uart_port *port,
324 struct ktermios *termios,
325 struct ktermios *old)
326 {
327 struct uart_8250_port *up = up_to_u8250p(port);
328 struct omap8250_priv *priv = up->port.private_data;
329 unsigned char cval = 0;
330 unsigned int baud;
331
332 switch (termios->c_cflag & CSIZE) {
333 case CS5:
334 cval = UART_LCR_WLEN5;
335 break;
336 case CS6:
337 cval = UART_LCR_WLEN6;
338 break;
339 case CS7:
340 cval = UART_LCR_WLEN7;
341 break;
342 default:
343 case CS8:
344 cval = UART_LCR_WLEN8;
345 break;
346 }
347
348 if (termios->c_cflag & CSTOPB)
349 cval |= UART_LCR_STOP;
350 if (termios->c_cflag & PARENB)
351 cval |= UART_LCR_PARITY;
352 if (!(termios->c_cflag & PARODD))
353 cval |= UART_LCR_EPAR;
354 if (termios->c_cflag & CMSPAR)
355 cval |= UART_LCR_SPAR;
356
357 /*
358 * Ask the core to calculate the divisor for us.
359 */
360 baud = uart_get_baud_rate(port, termios, old,
361 port->uartclk / 16 / 0xffff,
362 port->uartclk / 13);
363 omap_8250_get_divisor(port, baud, priv);
364
365 /*
366 * Ok, we're now changing the port state. Do it with
367 * interrupts disabled.
368 */
369 pm_runtime_get_sync(port->dev);
370 spin_lock_irq(&port->lock);
371
372 /*
373 * Update the per-port timeout.
374 */
375 uart_update_timeout(port, termios->c_cflag, baud);
376
377 up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
378 if (termios->c_iflag & INPCK)
379 up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE;
380 if (termios->c_iflag & (IGNBRK | PARMRK))
381 up->port.read_status_mask |= UART_LSR_BI;
382
383 /*
384 * Characters to ignore
385 */
386 up->port.ignore_status_mask = 0;
387 if (termios->c_iflag & IGNPAR)
388 up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
389 if (termios->c_iflag & IGNBRK) {
390 up->port.ignore_status_mask |= UART_LSR_BI;
391 /*
392 * If we're ignoring parity and break indicators,
393 * ignore overruns too (for real raw support).
394 */
395 if (termios->c_iflag & IGNPAR)
396 up->port.ignore_status_mask |= UART_LSR_OE;
397 }
398
399 /*
400 * ignore all characters if CREAD is not set
401 */
402 if ((termios->c_cflag & CREAD) == 0)
403 up->port.ignore_status_mask |= UART_LSR_DR;
404
405 /*
406 * Modem status interrupts
407 */
408 up->ier &= ~UART_IER_MSI;
409 if (UART_ENABLE_MS(&up->port, termios->c_cflag))
410 up->ier |= UART_IER_MSI;
411
412 up->lcr = cval;
413 /* Up to here it was mostly serial8250_do_set_termios() */
414
415 /*
416 * We enable TRIG_GRANU for RX and TX and additionaly we set
417 * SCR_TX_EMPTY bit. The result is the following:
418 * - RX_TRIGGER amount of bytes in the FIFO will cause an interrupt.
419 * - less than RX_TRIGGER number of bytes will also cause an interrupt
420 * once the UART decides that there no new bytes arriving.
421 * - Once THRE is enabled, the interrupt will be fired once the FIFO is
422 * empty - the trigger level is ignored here.
423 *
424 * Once DMA is enabled:
425 * - UART will assert the TX DMA line once there is room for TX_TRIGGER
426 * bytes in the TX FIFO. On each assert the DMA engine will move
427 * TX_TRIGGER bytes into the FIFO.
428 * - UART will assert the RX DMA line once there are RX_TRIGGER bytes in
429 * the FIFO and move RX_TRIGGER bytes.
430 * This is because threshold and trigger values are the same.
431 */
432 up->fcr = UART_FCR_ENABLE_FIFO;
433 up->fcr |= TRIGGER_FCR_MASK(TX_TRIGGER) << OMAP_UART_FCR_TX_TRIG;
434 up->fcr |= TRIGGER_FCR_MASK(RX_TRIGGER) << OMAP_UART_FCR_RX_TRIG;
435
436 priv->scr = OMAP_UART_SCR_RX_TRIG_GRANU1_MASK | OMAP_UART_SCR_TX_EMPTY |
437 OMAP_UART_SCR_TX_TRIG_GRANU1_MASK;
438
439 if (up->dma)
440 priv->scr |= OMAP_UART_SCR_DMAMODE_1 |
441 OMAP_UART_SCR_DMAMODE_CTL;
442
443 priv->xon = termios->c_cc[VSTART];
444 priv->xoff = termios->c_cc[VSTOP];
445
446 priv->efr = 0;
447 up->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS | UPSTAT_AUTOXOFF);
448
449 if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW) {
450 /* Enable AUTOCTS (autoRTS is enabled when RTS is raised) */
451 up->port.status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
452 priv->efr |= UART_EFR_CTS;
453 } else if (up->port.flags & UPF_SOFT_FLOW) {
454 /*
455 * OMAP rx s/w flow control is borked; the transmitter remains
456 * stuck off even if rx flow control is subsequently disabled
457 */
458
459 /*
460 * IXOFF Flag:
461 * Enable XON/XOFF flow control on output.
462 * Transmit XON1, XOFF1
463 */
464 if (termios->c_iflag & IXOFF) {
465 up->port.status |= UPSTAT_AUTOXOFF;
466 priv->efr |= OMAP_UART_SW_TX;
467 }
468 }
469 omap8250_restore_regs(up);
470
471 spin_unlock_irq(&up->port.lock);
472 pm_runtime_mark_last_busy(port->dev);
473 pm_runtime_put_autosuspend(port->dev);
474
475 /* calculate wakeup latency constraint */
476 priv->calc_latency = USEC_PER_SEC * 64 * 8 / baud;
477 priv->latency = priv->calc_latency;
478
479 schedule_work(&priv->qos_work);
480
481 /* Don't rewrite B0 */
482 if (tty_termios_baud_rate(termios))
483 tty_termios_encode_baud_rate(termios, baud, baud);
484 }
485
486 /* same as 8250 except that we may have extra flow bits set in EFR */
487 static void omap_8250_pm(struct uart_port *port, unsigned int state,
488 unsigned int oldstate)
489 {
490 struct uart_8250_port *up = up_to_u8250p(port);
491 u8 efr;
492
493 pm_runtime_get_sync(port->dev);
494 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
495 efr = serial_in(up, UART_EFR);
496 serial_out(up, UART_EFR, efr | UART_EFR_ECB);
497 serial_out(up, UART_LCR, 0);
498
499 serial_out(up, UART_IER, (state != 0) ? UART_IERX_SLEEP : 0);
500 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
501 serial_out(up, UART_EFR, efr);
502 serial_out(up, UART_LCR, 0);
503
504 pm_runtime_mark_last_busy(port->dev);
505 pm_runtime_put_autosuspend(port->dev);
506 }
507
508 static void omap_serial_fill_features_erratas(struct uart_8250_port *up,
509 struct omap8250_priv *priv)
510 {
511 u32 mvr, scheme;
512 u16 revision, major, minor;
513
514 mvr = uart_read(up, UART_OMAP_MVER);
515
516 /* Check revision register scheme */
517 scheme = mvr >> OMAP_UART_MVR_SCHEME_SHIFT;
518
519 switch (scheme) {
520 case 0: /* Legacy Scheme: OMAP2/3 */
521 /* MINOR_REV[0:4], MAJOR_REV[4:7] */
522 major = (mvr & OMAP_UART_LEGACY_MVR_MAJ_MASK) >>
523 OMAP_UART_LEGACY_MVR_MAJ_SHIFT;
524 minor = (mvr & OMAP_UART_LEGACY_MVR_MIN_MASK);
525 break;
526 case 1:
527 /* New Scheme: OMAP4+ */
528 /* MINOR_REV[0:5], MAJOR_REV[8:10] */
529 major = (mvr & OMAP_UART_MVR_MAJ_MASK) >>
530 OMAP_UART_MVR_MAJ_SHIFT;
531 minor = (mvr & OMAP_UART_MVR_MIN_MASK);
532 break;
533 default:
534 dev_warn(up->port.dev,
535 "Unknown revision, defaulting to highest\n");
536 /* highest possible revision */
537 major = 0xff;
538 minor = 0xff;
539 }
540 /* normalize revision for the driver */
541 revision = UART_BUILD_REVISION(major, minor);
542
543 switch (revision) {
544 case OMAP_UART_REV_46:
545 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS;
546 break;
547 case OMAP_UART_REV_52:
548 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS |
549 OMAP_UART_WER_HAS_TX_WAKEUP;
550 break;
551 case OMAP_UART_REV_63:
552 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS |
553 OMAP_UART_WER_HAS_TX_WAKEUP;
554 break;
555 default:
556 break;
557 }
558 }
559
560 static void omap8250_uart_qos_work(struct work_struct *work)
561 {
562 struct omap8250_priv *priv;
563
564 priv = container_of(work, struct omap8250_priv, qos_work);
565 pm_qos_update_request(&priv->pm_qos_request, priv->latency);
566 }
567
568 #ifdef CONFIG_SERIAL_8250_DMA
569 static int omap_8250_dma_handle_irq(struct uart_port *port);
570 #endif
571
572 static irqreturn_t omap8250_irq(int irq, void *dev_id)
573 {
574 struct uart_port *port = dev_id;
575 struct uart_8250_port *up = up_to_u8250p(port);
576 unsigned int iir;
577 int ret;
578
579 #ifdef CONFIG_SERIAL_8250_DMA
580 if (up->dma) {
581 ret = omap_8250_dma_handle_irq(port);
582 return IRQ_RETVAL(ret);
583 }
584 #endif
585
586 serial8250_rpm_get(up);
587 iir = serial_port_in(port, UART_IIR);
588 ret = serial8250_handle_irq(port, iir);
589 serial8250_rpm_put(up);
590
591 return IRQ_RETVAL(ret);
592 }
593
594 static int omap_8250_startup(struct uart_port *port)
595 {
596 struct uart_8250_port *up = up_to_u8250p(port);
597 struct omap8250_priv *priv = port->private_data;
598 int ret;
599
600 if (priv->wakeirq) {
601 ret = dev_pm_set_dedicated_wake_irq(port->dev, priv->wakeirq);
602 if (ret)
603 return ret;
604 }
605
606 pm_runtime_get_sync(port->dev);
607
608 up->mcr = 0;
609 serial_out(up, UART_FCR, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
610
611 serial_out(up, UART_LCR, UART_LCR_WLEN8);
612
613 up->lsr_saved_flags = 0;
614 up->msr_saved_flags = 0;
615
616 if (up->dma) {
617 ret = serial8250_request_dma(up);
618 if (ret) {
619 dev_warn_ratelimited(port->dev,
620 "failed to request DMA\n");
621 up->dma = NULL;
622 }
623 }
624
625 ret = request_irq(port->irq, omap8250_irq, IRQF_SHARED,
626 dev_name(port->dev), port);
627 if (ret < 0)
628 goto err;
629
630 up->ier = UART_IER_RLSI | UART_IER_RDI;
631 serial_out(up, UART_IER, up->ier);
632
633 #ifdef CONFIG_PM
634 up->capabilities |= UART_CAP_RPM;
635 #endif
636
637 /* Enable module level wake up */
638 priv->wer = OMAP_UART_WER_MOD_WKUP;
639 if (priv->habit & OMAP_UART_WER_HAS_TX_WAKEUP)
640 priv->wer |= OMAP_UART_TX_WAKEUP_EN;
641 serial_out(up, UART_OMAP_WER, priv->wer);
642
643 if (up->dma)
644 up->dma->rx_dma(up);
645
646 pm_runtime_mark_last_busy(port->dev);
647 pm_runtime_put_autosuspend(port->dev);
648 return 0;
649 err:
650 pm_runtime_mark_last_busy(port->dev);
651 pm_runtime_put_autosuspend(port->dev);
652 dev_pm_clear_wake_irq(port->dev);
653 return ret;
654 }
655
656 static void omap_8250_shutdown(struct uart_port *port)
657 {
658 struct uart_8250_port *up = up_to_u8250p(port);
659 struct omap8250_priv *priv = port->private_data;
660
661 flush_work(&priv->qos_work);
662 if (up->dma)
663 omap_8250_rx_dma_flush(up);
664
665 pm_runtime_get_sync(port->dev);
666
667 serial_out(up, UART_OMAP_WER, 0);
668
669 up->ier = 0;
670 serial_out(up, UART_IER, 0);
671
672 if (up->dma)
673 serial8250_release_dma(up);
674
675 /*
676 * Disable break condition and FIFOs
677 */
678 if (up->lcr & UART_LCR_SBC)
679 serial_out(up, UART_LCR, up->lcr & ~UART_LCR_SBC);
680 serial_out(up, UART_FCR, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
681
682 pm_runtime_mark_last_busy(port->dev);
683 pm_runtime_put_autosuspend(port->dev);
684 free_irq(port->irq, port);
685 dev_pm_clear_wake_irq(port->dev);
686 }
687
688 static void omap_8250_throttle(struct uart_port *port)
689 {
690 struct uart_8250_port *up = up_to_u8250p(port);
691 unsigned long flags;
692
693 pm_runtime_get_sync(port->dev);
694
695 spin_lock_irqsave(&port->lock, flags);
696 up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
697 serial_out(up, UART_IER, up->ier);
698 spin_unlock_irqrestore(&port->lock, flags);
699
700 pm_runtime_mark_last_busy(port->dev);
701 pm_runtime_put_autosuspend(port->dev);
702 }
703
704 static int omap_8250_rs485_config(struct uart_port *port,
705 struct serial_rs485 *rs485)
706 {
707 struct uart_8250_port *up = up_to_u8250p(port);
708
709 /* Clamp the delays to [0, 100ms] */
710 rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U);
711 rs485->delay_rts_after_send = min(rs485->delay_rts_after_send, 100U);
712
713 port->rs485 = *rs485;
714
715 /*
716 * Both serial8250_em485_init and serial8250_em485_destroy
717 * are idempotent
718 */
719 if (rs485->flags & SER_RS485_ENABLED) {
720 int ret = serial8250_em485_init(up);
721
722 if (ret) {
723 rs485->flags &= ~SER_RS485_ENABLED;
724 port->rs485.flags &= ~SER_RS485_ENABLED;
725 }
726 return ret;
727 }
728
729 serial8250_em485_destroy(up);
730
731 return 0;
732 }
733
734 static void omap_8250_unthrottle(struct uart_port *port)
735 {
736 struct uart_8250_port *up = up_to_u8250p(port);
737 unsigned long flags;
738
739 pm_runtime_get_sync(port->dev);
740
741 spin_lock_irqsave(&port->lock, flags);
742 up->ier |= UART_IER_RLSI | UART_IER_RDI;
743 serial_out(up, UART_IER, up->ier);
744 spin_unlock_irqrestore(&port->lock, flags);
745
746 pm_runtime_mark_last_busy(port->dev);
747 pm_runtime_put_autosuspend(port->dev);
748 }
749
750 #ifdef CONFIG_SERIAL_8250_DMA
751 static int omap_8250_rx_dma(struct uart_8250_port *p);
752
753 static void __dma_rx_do_complete(struct uart_8250_port *p)
754 {
755 struct omap8250_priv *priv = p->port.private_data;
756 struct uart_8250_dma *dma = p->dma;
757 struct tty_port *tty_port = &p->port.state->port;
758 struct dma_tx_state state;
759 int count;
760 unsigned long flags;
761 int ret;
762
763 spin_lock_irqsave(&priv->rx_dma_lock, flags);
764
765 if (!dma->rx_running)
766 goto unlock;
767
768 dma->rx_running = 0;
769 dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state);
770
771 count = dma->rx_size - state.residue;
772
773 ret = tty_insert_flip_string(tty_port, dma->rx_buf, count);
774
775 p->port.icount.rx += ret;
776 p->port.icount.buf_overrun += count - ret;
777 unlock:
778 spin_unlock_irqrestore(&priv->rx_dma_lock, flags);
779
780 tty_flip_buffer_push(tty_port);
781 }
782
783 static void __dma_rx_complete(void *param)
784 {
785 __dma_rx_do_complete(param);
786 omap_8250_rx_dma(param);
787 }
788
789 static void omap_8250_rx_dma_flush(struct uart_8250_port *p)
790 {
791 struct omap8250_priv *priv = p->port.private_data;
792 struct uart_8250_dma *dma = p->dma;
793 unsigned long flags;
794 int ret;
795
796 spin_lock_irqsave(&priv->rx_dma_lock, flags);
797
798 if (!dma->rx_running) {
799 spin_unlock_irqrestore(&priv->rx_dma_lock, flags);
800 return;
801 }
802
803 ret = dmaengine_pause(dma->rxchan);
804 if (WARN_ON_ONCE(ret))
805 priv->rx_dma_broken = true;
806
807 spin_unlock_irqrestore(&priv->rx_dma_lock, flags);
808
809 __dma_rx_do_complete(p);
810 dmaengine_terminate_all(dma->rxchan);
811 }
812
813 static int omap_8250_rx_dma(struct uart_8250_port *p)
814 {
815 struct omap8250_priv *priv = p->port.private_data;
816 struct uart_8250_dma *dma = p->dma;
817 int err = 0;
818 struct dma_async_tx_descriptor *desc;
819 unsigned long flags;
820
821 if (priv->rx_dma_broken)
822 return -EINVAL;
823
824 spin_lock_irqsave(&priv->rx_dma_lock, flags);
825
826 if (dma->rx_running)
827 goto out;
828
829 desc = dmaengine_prep_slave_single(dma->rxchan, dma->rx_addr,
830 dma->rx_size, DMA_DEV_TO_MEM,
831 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
832 if (!desc) {
833 err = -EBUSY;
834 goto out;
835 }
836
837 dma->rx_running = 1;
838 desc->callback = __dma_rx_complete;
839 desc->callback_param = p;
840
841 dma->rx_cookie = dmaengine_submit(desc);
842
843 dma_async_issue_pending(dma->rxchan);
844 out:
845 spin_unlock_irqrestore(&priv->rx_dma_lock, flags);
846 return err;
847 }
848
849 static int omap_8250_tx_dma(struct uart_8250_port *p);
850
851 static void omap_8250_dma_tx_complete(void *param)
852 {
853 struct uart_8250_port *p = param;
854 struct uart_8250_dma *dma = p->dma;
855 struct circ_buf *xmit = &p->port.state->xmit;
856 unsigned long flags;
857 bool en_thri = false;
858 struct omap8250_priv *priv = p->port.private_data;
859
860 dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr,
861 UART_XMIT_SIZE, DMA_TO_DEVICE);
862
863 spin_lock_irqsave(&p->port.lock, flags);
864
865 dma->tx_running = 0;
866
867 xmit->tail += dma->tx_size;
868 xmit->tail &= UART_XMIT_SIZE - 1;
869 p->port.icount.tx += dma->tx_size;
870
871 if (priv->delayed_restore) {
872 priv->delayed_restore = 0;
873 omap8250_restore_regs(p);
874 }
875
876 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
877 uart_write_wakeup(&p->port);
878
879 if (!uart_circ_empty(xmit) && !uart_tx_stopped(&p->port)) {
880 int ret;
881
882 ret = omap_8250_tx_dma(p);
883 if (ret)
884 en_thri = true;
885
886 } else if (p->capabilities & UART_CAP_RPM) {
887 en_thri = true;
888 }
889
890 if (en_thri) {
891 dma->tx_err = 1;
892 p->ier |= UART_IER_THRI;
893 serial_port_out(&p->port, UART_IER, p->ier);
894 }
895
896 spin_unlock_irqrestore(&p->port.lock, flags);
897 }
898
899 static int omap_8250_tx_dma(struct uart_8250_port *p)
900 {
901 struct uart_8250_dma *dma = p->dma;
902 struct omap8250_priv *priv = p->port.private_data;
903 struct circ_buf *xmit = &p->port.state->xmit;
904 struct dma_async_tx_descriptor *desc;
905 unsigned int skip_byte = 0;
906 int ret;
907
908 if (dma->tx_running)
909 return 0;
910 if (uart_tx_stopped(&p->port) || uart_circ_empty(xmit)) {
911
912 /*
913 * Even if no data, we need to return an error for the two cases
914 * below so serial8250_tx_chars() is invoked and properly clears
915 * THRI and/or runtime suspend.
916 */
917 if (dma->tx_err || p->capabilities & UART_CAP_RPM) {
918 ret = -EBUSY;
919 goto err;
920 }
921 if (p->ier & UART_IER_THRI) {
922 p->ier &= ~UART_IER_THRI;
923 serial_out(p, UART_IER, p->ier);
924 }
925 return 0;
926 }
927
928 dma->tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
929 if (priv->habit & OMAP_DMA_TX_KICK) {
930 u8 tx_lvl;
931
932 /*
933 * We need to put the first byte into the FIFO in order to start
934 * the DMA transfer. For transfers smaller than four bytes we
935 * don't bother doing DMA at all. It seem not matter if there
936 * are still bytes in the FIFO from the last transfer (in case
937 * we got here directly from omap_8250_dma_tx_complete()). Bytes
938 * leaving the FIFO seem not to trigger the DMA transfer. It is
939 * really the byte that we put into the FIFO.
940 * If the FIFO is already full then we most likely got here from
941 * omap_8250_dma_tx_complete(). And this means the DMA engine
942 * just completed its work. We don't have to wait the complete
943 * 86us at 115200,8n1 but around 60us (not to mention lower
944 * baudrates). So in that case we take the interrupt and try
945 * again with an empty FIFO.
946 */
947 tx_lvl = serial_in(p, UART_OMAP_TX_LVL);
948 if (tx_lvl == p->tx_loadsz) {
949 ret = -EBUSY;
950 goto err;
951 }
952 if (dma->tx_size < 4) {
953 ret = -EINVAL;
954 goto err;
955 }
956 skip_byte = 1;
957 }
958
959 desc = dmaengine_prep_slave_single(dma->txchan,
960 dma->tx_addr + xmit->tail + skip_byte,
961 dma->tx_size - skip_byte, DMA_MEM_TO_DEV,
962 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
963 if (!desc) {
964 ret = -EBUSY;
965 goto err;
966 }
967
968 dma->tx_running = 1;
969
970 desc->callback = omap_8250_dma_tx_complete;
971 desc->callback_param = p;
972
973 dma->tx_cookie = dmaengine_submit(desc);
974
975 dma_sync_single_for_device(dma->txchan->device->dev, dma->tx_addr,
976 UART_XMIT_SIZE, DMA_TO_DEVICE);
977
978 dma_async_issue_pending(dma->txchan);
979 if (dma->tx_err)
980 dma->tx_err = 0;
981
982 if (p->ier & UART_IER_THRI) {
983 p->ier &= ~UART_IER_THRI;
984 serial_out(p, UART_IER, p->ier);
985 }
986 if (skip_byte)
987 serial_out(p, UART_TX, xmit->buf[xmit->tail]);
988 return 0;
989 err:
990 dma->tx_err = 1;
991 return ret;
992 }
993
994 static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir)
995 {
996 switch (iir & 0x3f) {
997 case UART_IIR_RLSI:
998 case UART_IIR_RX_TIMEOUT:
999 case UART_IIR_RDI:
1000 omap_8250_rx_dma_flush(up);
1001 return true;
1002 }
1003 return omap_8250_rx_dma(up);
1004 }
1005
1006 /*
1007 * This is mostly serial8250_handle_irq(). We have a slightly different DMA
1008 * hoook for RX/TX and need different logic for them in the ISR. Therefore we
1009 * use the default routine in the non-DMA case and this one for with DMA.
1010 */
1011 static int omap_8250_dma_handle_irq(struct uart_port *port)
1012 {
1013 struct uart_8250_port *up = up_to_u8250p(port);
1014 unsigned char status;
1015 unsigned long flags;
1016 u8 iir;
1017
1018 serial8250_rpm_get(up);
1019
1020 iir = serial_port_in(port, UART_IIR);
1021 if (iir & UART_IIR_NO_INT) {
1022 serial8250_rpm_put(up);
1023 return 0;
1024 }
1025
1026 spin_lock_irqsave(&port->lock, flags);
1027
1028 status = serial_port_in(port, UART_LSR);
1029
1030 if (status & (UART_LSR_DR | UART_LSR_BI)) {
1031 if (handle_rx_dma(up, iir)) {
1032 status = serial8250_rx_chars(up, status);
1033 omap_8250_rx_dma(up);
1034 }
1035 }
1036 serial8250_modem_status(up);
1037 if (status & UART_LSR_THRE && up->dma->tx_err) {
1038 if (uart_tx_stopped(&up->port) ||
1039 uart_circ_empty(&up->port.state->xmit)) {
1040 up->dma->tx_err = 0;
1041 serial8250_tx_chars(up);
1042 } else {
1043 /*
1044 * try again due to an earlier failer which
1045 * might have been resolved by now.
1046 */
1047 if (omap_8250_tx_dma(up))
1048 serial8250_tx_chars(up);
1049 }
1050 }
1051
1052 spin_unlock_irqrestore(&port->lock, flags);
1053 serial8250_rpm_put(up);
1054 return 1;
1055 }
1056
1057 static bool the_no_dma_filter_fn(struct dma_chan *chan, void *param)
1058 {
1059 return false;
1060 }
1061
1062 #else
1063
1064 static inline int omap_8250_rx_dma(struct uart_8250_port *p)
1065 {
1066 return -EINVAL;
1067 }
1068 #endif
1069
1070 static int omap8250_no_handle_irq(struct uart_port *port)
1071 {
1072 /* IRQ has not been requested but handling irq? */
1073 WARN_ONCE(1, "Unexpected irq handling before port startup\n");
1074 return 0;
1075 }
1076
1077 static const u8 am3352_habit = OMAP_DMA_TX_KICK | UART_ERRATA_CLOCK_DISABLE;
1078 static const u8 am4372_habit = UART_ERRATA_CLOCK_DISABLE;
1079
1080 static const struct of_device_id omap8250_dt_ids[] = {
1081 { .compatible = "ti,omap2-uart" },
1082 { .compatible = "ti,omap3-uart" },
1083 { .compatible = "ti,omap4-uart" },
1084 { .compatible = "ti,am3352-uart", .data = &am3352_habit, },
1085 { .compatible = "ti,am4372-uart", .data = &am4372_habit, },
1086 { .compatible = "ti,dra742-uart", .data = &am4372_habit, },
1087 {},
1088 };
1089 MODULE_DEVICE_TABLE(of, omap8250_dt_ids);
1090
1091 static int omap8250_probe(struct platform_device *pdev)
1092 {
1093 struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1094 struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
1095 struct omap8250_priv *priv;
1096 struct uart_8250_port up;
1097 int ret;
1098 void __iomem *membase;
1099
1100 if (!regs || !irq) {
1101 dev_err(&pdev->dev, "missing registers or irq\n");
1102 return -EINVAL;
1103 }
1104
1105 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
1106 if (!priv)
1107 return -ENOMEM;
1108
1109 membase = devm_ioremap_nocache(&pdev->dev, regs->start,
1110 resource_size(regs));
1111 if (!membase)
1112 return -ENODEV;
1113
1114 memset(&up, 0, sizeof(up));
1115 up.port.dev = &pdev->dev;
1116 up.port.mapbase = regs->start;
1117 up.port.membase = membase;
1118 up.port.irq = irq->start;
1119 /*
1120 * It claims to be 16C750 compatible however it is a little different.
1121 * It has EFR and has no FCR7_64byte bit. The AFE (which it claims to
1122 * have) is enabled via EFR instead of MCR. The type is set here 8250
1123 * just to get things going. UNKNOWN does not work for a few reasons and
1124 * we don't need our own type since we don't use 8250's set_termios()
1125 * or pm callback.
1126 */
1127 up.port.type = PORT_8250;
1128 up.port.iotype = UPIO_MEM;
1129 up.port.flags = UPF_FIXED_PORT | UPF_FIXED_TYPE | UPF_SOFT_FLOW |
1130 UPF_HARD_FLOW;
1131 up.port.private_data = priv;
1132
1133 up.port.regshift = 2;
1134 up.port.fifosize = 64;
1135 up.tx_loadsz = 64;
1136 up.capabilities = UART_CAP_FIFO;
1137 #ifdef CONFIG_PM
1138 /*
1139 * Runtime PM is mostly transparent. However to do it right we need to a
1140 * TX empty interrupt before we can put the device to auto idle. So if
1141 * PM is not enabled we don't add that flag and can spare that one extra
1142 * interrupt in the TX path.
1143 */
1144 up.capabilities |= UART_CAP_RPM;
1145 #endif
1146 up.port.set_termios = omap_8250_set_termios;
1147 up.port.set_mctrl = omap8250_set_mctrl;
1148 up.port.pm = omap_8250_pm;
1149 up.port.startup = omap_8250_startup;
1150 up.port.shutdown = omap_8250_shutdown;
1151 up.port.throttle = omap_8250_throttle;
1152 up.port.unthrottle = omap_8250_unthrottle;
1153 up.port.rs485_config = omap_8250_rs485_config;
1154
1155 if (pdev->dev.of_node) {
1156 const struct of_device_id *id;
1157
1158 ret = of_alias_get_id(pdev->dev.of_node, "serial");
1159
1160 of_property_read_u32(pdev->dev.of_node, "clock-frequency",
1161 &up.port.uartclk);
1162 priv->wakeirq = irq_of_parse_and_map(pdev->dev.of_node, 1);
1163
1164 id = of_match_device(of_match_ptr(omap8250_dt_ids), &pdev->dev);
1165 if (id && id->data)
1166 priv->habit |= *(u8 *)id->data;
1167 } else {
1168 ret = pdev->id;
1169 }
1170 if (ret < 0) {
1171 dev_err(&pdev->dev, "failed to get alias/pdev id\n");
1172 return ret;
1173 }
1174 up.port.line = ret;
1175
1176 if (!up.port.uartclk) {
1177 up.port.uartclk = DEFAULT_CLK_SPEED;
1178 dev_warn(&pdev->dev,
1179 "No clock speed specified: using default: %d\n",
1180 DEFAULT_CLK_SPEED);
1181 }
1182
1183 priv->latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;
1184 priv->calc_latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;
1185 pm_qos_add_request(&priv->pm_qos_request, PM_QOS_CPU_DMA_LATENCY,
1186 priv->latency);
1187 INIT_WORK(&priv->qos_work, omap8250_uart_qos_work);
1188
1189 spin_lock_init(&priv->rx_dma_lock);
1190
1191 device_init_wakeup(&pdev->dev, true);
1192 pm_runtime_use_autosuspend(&pdev->dev);
1193 pm_runtime_set_autosuspend_delay(&pdev->dev, -1);
1194
1195 pm_runtime_irq_safe(&pdev->dev);
1196 pm_runtime_enable(&pdev->dev);
1197
1198 pm_runtime_get_sync(&pdev->dev);
1199
1200 omap_serial_fill_features_erratas(&up, priv);
1201 up.port.handle_irq = omap8250_no_handle_irq;
1202 #ifdef CONFIG_SERIAL_8250_DMA
1203 if (pdev->dev.of_node) {
1204 /*
1205 * Oh DMA support. If there are no DMA properties in the DT then
1206 * we will fall back to a generic DMA channel which does not
1207 * really work here. To ensure that we do not get a generic DMA
1208 * channel assigned, we have the the_no_dma_filter_fn() here.
1209 * To avoid "failed to request DMA" messages we check for DMA
1210 * properties in DT.
1211 */
1212 ret = of_property_count_strings(pdev->dev.of_node, "dma-names");
1213 if (ret == 2) {
1214 up.dma = &priv->omap8250_dma;
1215 priv->omap8250_dma.fn = the_no_dma_filter_fn;
1216 priv->omap8250_dma.tx_dma = omap_8250_tx_dma;
1217 priv->omap8250_dma.rx_dma = omap_8250_rx_dma;
1218 priv->omap8250_dma.rx_size = RX_TRIGGER;
1219 priv->omap8250_dma.rxconf.src_maxburst = RX_TRIGGER;
1220 priv->omap8250_dma.txconf.dst_maxburst = TX_TRIGGER;
1221
1222 if (of_machine_is_compatible("ti,am33xx"))
1223 priv->habit |= OMAP_DMA_TX_KICK;
1224 /*
1225 * pause is currently not supported atleast on omap-sdma
1226 * and edma on most earlier kernels.
1227 */
1228 priv->rx_dma_broken = true;
1229 }
1230 }
1231 #endif
1232 ret = serial8250_register_8250_port(&up);
1233 if (ret < 0) {
1234 dev_err(&pdev->dev, "unable to register 8250 port\n");
1235 goto err;
1236 }
1237 priv->line = ret;
1238 platform_set_drvdata(pdev, priv);
1239 pm_runtime_mark_last_busy(&pdev->dev);
1240 pm_runtime_put_autosuspend(&pdev->dev);
1241 return 0;
1242 err:
1243 pm_runtime_put(&pdev->dev);
1244 pm_runtime_disable(&pdev->dev);
1245 return ret;
1246 }
1247
1248 static int omap8250_remove(struct platform_device *pdev)
1249 {
1250 struct omap8250_priv *priv = platform_get_drvdata(pdev);
1251
1252 pm_runtime_put_sync(&pdev->dev);
1253 pm_runtime_disable(&pdev->dev);
1254 serial8250_unregister_port(priv->line);
1255 pm_qos_remove_request(&priv->pm_qos_request);
1256 device_init_wakeup(&pdev->dev, false);
1257 return 0;
1258 }
1259
1260 #ifdef CONFIG_PM_SLEEP
1261 static int omap8250_prepare(struct device *dev)
1262 {
1263 struct omap8250_priv *priv = dev_get_drvdata(dev);
1264
1265 if (!priv)
1266 return 0;
1267 priv->is_suspending = true;
1268 return 0;
1269 }
1270
1271 static void omap8250_complete(struct device *dev)
1272 {
1273 struct omap8250_priv *priv = dev_get_drvdata(dev);
1274
1275 if (!priv)
1276 return;
1277 priv->is_suspending = false;
1278 }
1279
1280 static int omap8250_suspend(struct device *dev)
1281 {
1282 struct omap8250_priv *priv = dev_get_drvdata(dev);
1283
1284 serial8250_suspend_port(priv->line);
1285 flush_work(&priv->qos_work);
1286 return 0;
1287 }
1288
1289 static int omap8250_resume(struct device *dev)
1290 {
1291 struct omap8250_priv *priv = dev_get_drvdata(dev);
1292
1293 serial8250_resume_port(priv->line);
1294 return 0;
1295 }
1296 #else
1297 #define omap8250_prepare NULL
1298 #define omap8250_complete NULL
1299 #endif
1300
1301 #ifdef CONFIG_PM
1302 static int omap8250_lost_context(struct uart_8250_port *up)
1303 {
1304 u32 val;
1305
1306 val = serial_in(up, UART_OMAP_SCR);
1307 /*
1308 * If we lose context, then SCR is set to its reset value of zero.
1309 * After set_termios() we set bit 3 of SCR (TX_EMPTY_CTL_IT) to 1,
1310 * among other bits, to never set the register back to zero again.
1311 */
1312 if (!val)
1313 return 1;
1314 return 0;
1315 }
1316
1317 /* TODO: in future, this should happen via API in drivers/reset/ */
1318 static int omap8250_soft_reset(struct device *dev)
1319 {
1320 struct omap8250_priv *priv = dev_get_drvdata(dev);
1321 struct uart_8250_port *up = serial8250_get_port(priv->line);
1322 int timeout = 100;
1323 int sysc;
1324 int syss;
1325
1326 sysc = serial_in(up, UART_OMAP_SYSC);
1327
1328 /* softreset the UART */
1329 sysc |= OMAP_UART_SYSC_SOFTRESET;
1330 serial_out(up, UART_OMAP_SYSC, sysc);
1331
1332 /* By experiments, 1us enough for reset complete on AM335x */
1333 do {
1334 udelay(1);
1335 syss = serial_in(up, UART_OMAP_SYSS);
1336 } while (--timeout && !(syss & OMAP_UART_SYSS_RESETDONE));
1337
1338 if (!timeout) {
1339 dev_err(dev, "timed out waiting for reset done\n");
1340 return -ETIMEDOUT;
1341 }
1342
1343 return 0;
1344 }
1345
1346 static int omap8250_runtime_suspend(struct device *dev)
1347 {
1348 struct omap8250_priv *priv = dev_get_drvdata(dev);
1349 struct uart_8250_port *up;
1350
1351 up = serial8250_get_port(priv->line);
1352 /*
1353 * When using 'no_console_suspend', the console UART must not be
1354 * suspended. Since driver suspend is managed by runtime suspend,
1355 * preventing runtime suspend (by returning error) will keep device
1356 * active during suspend.
1357 */
1358 if (priv->is_suspending && !console_suspend_enabled) {
1359 if (uart_console(&up->port))
1360 return -EBUSY;
1361 }
1362
1363 if (priv->habit & UART_ERRATA_CLOCK_DISABLE) {
1364 int ret;
1365
1366 ret = omap8250_soft_reset(dev);
1367 if (ret)
1368 return ret;
1369
1370 /* Restore to UART mode after reset (for wakeup) */
1371 omap8250_update_mdr1(up, priv);
1372 }
1373
1374 if (up->dma && up->dma->rxchan)
1375 omap_8250_rx_dma_flush(up);
1376
1377 priv->latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;
1378 schedule_work(&priv->qos_work);
1379
1380 return 0;
1381 }
1382
1383 static int omap8250_runtime_resume(struct device *dev)
1384 {
1385 struct omap8250_priv *priv = dev_get_drvdata(dev);
1386 struct uart_8250_port *up;
1387
1388 /* In case runtime-pm tries this before we are setup */
1389 if (!priv)
1390 return 0;
1391
1392 up = serial8250_get_port(priv->line);
1393
1394 if (omap8250_lost_context(up))
1395 omap8250_restore_regs(up);
1396
1397 if (up->dma && up->dma->rxchan)
1398 omap_8250_rx_dma(up);
1399
1400 priv->latency = priv->calc_latency;
1401 schedule_work(&priv->qos_work);
1402 return 0;
1403 }
1404 #endif
1405
1406 #ifdef CONFIG_SERIAL_8250_OMAP_TTYO_FIXUP
1407 static int __init omap8250_console_fixup(void)
1408 {
1409 char *omap_str;
1410 char *options;
1411 u8 idx;
1412
1413 if (strstr(boot_command_line, "console=ttyS"))
1414 /* user set a ttyS based name for the console */
1415 return 0;
1416
1417 omap_str = strstr(boot_command_line, "console=ttyO");
1418 if (!omap_str)
1419 /* user did not set ttyO based console, so we don't care */
1420 return 0;
1421
1422 omap_str += 12;
1423 if ('0' <= *omap_str && *omap_str <= '9')
1424 idx = *omap_str - '0';
1425 else
1426 return 0;
1427
1428 omap_str++;
1429 if (omap_str[0] == ',') {
1430 omap_str++;
1431 options = omap_str;
1432 } else {
1433 options = NULL;
1434 }
1435
1436 add_preferred_console("ttyS", idx, options);
1437 pr_err("WARNING: Your 'console=ttyO%d' has been replaced by 'ttyS%d'\n",
1438 idx, idx);
1439 pr_err("This ensures that you still see kernel messages. Please\n");
1440 pr_err("update your kernel commandline.\n");
1441 return 0;
1442 }
1443 console_initcall(omap8250_console_fixup);
1444 #endif
1445
1446 static const struct dev_pm_ops omap8250_dev_pm_ops = {
1447 SET_SYSTEM_SLEEP_PM_OPS(omap8250_suspend, omap8250_resume)
1448 SET_RUNTIME_PM_OPS(omap8250_runtime_suspend,
1449 omap8250_runtime_resume, NULL)
1450 .prepare = omap8250_prepare,
1451 .complete = omap8250_complete,
1452 };
1453
1454 static struct platform_driver omap8250_platform_driver = {
1455 .driver = {
1456 .name = "omap8250",
1457 .pm = &omap8250_dev_pm_ops,
1458 .of_match_table = omap8250_dt_ids,
1459 },
1460 .probe = omap8250_probe,
1461 .remove = omap8250_remove,
1462 };
1463 module_platform_driver(omap8250_platform_driver);
1464
1465 MODULE_AUTHOR("Sebastian Andrzej Siewior");
1466 MODULE_DESCRIPTION("OMAP 8250 Driver");
1467 MODULE_LICENSE("GPL v2");