xref: /linux/drivers/tty/serial/8250/8250_omap.c (revision 2ba9268dd603d23e17643437b2246acb6844953b)
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_core.h>
15 #include <linux/serial_reg.h>
16 #include <linux/tty_flip.h>
17 #include <linux/platform_device.h>
18 #include <linux/slab.h>
19 #include <linux/of.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/dma-mapping.h>
27 
28 #include "8250.h"
29 
30 #define DEFAULT_CLK_SPEED	48000000
31 
32 #define UART_ERRATA_i202_MDR1_ACCESS	(1 << 0)
33 #define OMAP_UART_WER_HAS_TX_WAKEUP	(1 << 1)
34 #define OMAP_DMA_TX_KICK		(1 << 2)
35 
36 #define OMAP_UART_FCR_RX_TRIG		6
37 #define OMAP_UART_FCR_TX_TRIG		4
38 
39 /* SCR register bitmasks */
40 #define OMAP_UART_SCR_RX_TRIG_GRANU1_MASK	(1 << 7)
41 #define OMAP_UART_SCR_TX_TRIG_GRANU1_MASK	(1 << 6)
42 #define OMAP_UART_SCR_TX_EMPTY			(1 << 3)
43 #define OMAP_UART_SCR_DMAMODE_MASK		(3 << 1)
44 #define OMAP_UART_SCR_DMAMODE_1			(1 << 1)
45 #define OMAP_UART_SCR_DMAMODE_CTL		(1 << 0)
46 
47 /* MVR register bitmasks */
48 #define OMAP_UART_MVR_SCHEME_SHIFT	30
49 #define OMAP_UART_LEGACY_MVR_MAJ_MASK	0xf0
50 #define OMAP_UART_LEGACY_MVR_MAJ_SHIFT	4
51 #define OMAP_UART_LEGACY_MVR_MIN_MASK	0x0f
52 #define OMAP_UART_MVR_MAJ_MASK		0x700
53 #define OMAP_UART_MVR_MAJ_SHIFT		8
54 #define OMAP_UART_MVR_MIN_MASK		0x3f
55 
56 #define UART_TI752_TLR_TX	0
57 #define UART_TI752_TLR_RX	4
58 
59 #define TRIGGER_TLR_MASK(x)	((x & 0x3c) >> 2)
60 #define TRIGGER_FCR_MASK(x)	(x & 3)
61 
62 /* Enable XON/XOFF flow control on output */
63 #define OMAP_UART_SW_TX		0x08
64 /* Enable XON/XOFF flow control on input */
65 #define OMAP_UART_SW_RX		0x02
66 
67 #define OMAP_UART_WER_MOD_WKUP	0x7f
68 #define OMAP_UART_TX_WAKEUP_EN	(1 << 7)
69 
70 #define TX_TRIGGER	1
71 #define RX_TRIGGER	48
72 
73 #define OMAP_UART_TCR_RESTORE(x)	((x / 4) << 4)
74 #define OMAP_UART_TCR_HALT(x)		((x / 4) << 0)
75 
76 #define UART_BUILD_REVISION(x, y)	(((x) << 8) | (y))
77 
78 #define OMAP_UART_REV_46 0x0406
79 #define OMAP_UART_REV_52 0x0502
80 #define OMAP_UART_REV_63 0x0603
81 
82 struct omap8250_priv {
83 	int line;
84 	u8 habit;
85 	u8 mdr1;
86 	u8 efr;
87 	u8 scr;
88 	u8 wer;
89 	u8 xon;
90 	u8 xoff;
91 	u8 delayed_restore;
92 	u16 quot;
93 
94 	bool is_suspending;
95 	int wakeirq;
96 	int wakeups_enabled;
97 	u32 latency;
98 	u32 calc_latency;
99 	struct pm_qos_request pm_qos_request;
100 	struct work_struct qos_work;
101 	struct uart_8250_dma omap8250_dma;
102 };
103 
104 static u32 uart_read(struct uart_8250_port *up, u32 reg)
105 {
106 	return readl(up->port.membase + (reg << up->port.regshift));
107 }
108 
109 static void omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl)
110 {
111 	struct uart_8250_port *up = up_to_u8250p(port);
112 	struct omap8250_priv *priv = up->port.private_data;
113 	u8 lcr;
114 
115 	serial8250_do_set_mctrl(port, mctrl);
116 
117 	/*
118 	 * Turn off autoRTS if RTS is lowered and restore autoRTS setting
119 	 * if RTS is raised
120 	 */
121 	lcr = serial_in(up, UART_LCR);
122 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
123 	if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS))
124 		priv->efr |= UART_EFR_RTS;
125 	else
126 		priv->efr &= ~UART_EFR_RTS;
127 	serial_out(up, UART_EFR, priv->efr);
128 	serial_out(up, UART_LCR, lcr);
129 }
130 
131 /*
132  * Work Around for Errata i202 (2430, 3430, 3630, 4430 and 4460)
133  * The access to uart register after MDR1 Access
134  * causes UART to corrupt data.
135  *
136  * Need a delay =
137  * 5 L4 clock cycles + 5 UART functional clock cycle (@48MHz = ~0.2uS)
138  * give 10 times as much
139  */
140 static void omap_8250_mdr1_errataset(struct uart_8250_port *up,
141 				     struct omap8250_priv *priv)
142 {
143 	u8 timeout = 255;
144 	u8 old_mdr1;
145 
146 	old_mdr1 = serial_in(up, UART_OMAP_MDR1);
147 	if (old_mdr1 == priv->mdr1)
148 		return;
149 
150 	serial_out(up, UART_OMAP_MDR1, priv->mdr1);
151 	udelay(2);
152 	serial_out(up, UART_FCR, up->fcr | UART_FCR_CLEAR_XMIT |
153 			UART_FCR_CLEAR_RCVR);
154 	/*
155 	 * Wait for FIFO to empty: when empty, RX_FIFO_E bit is 0 and
156 	 * TX_FIFO_E bit is 1.
157 	 */
158 	while (UART_LSR_THRE != (serial_in(up, UART_LSR) &
159 				(UART_LSR_THRE | UART_LSR_DR))) {
160 		timeout--;
161 		if (!timeout) {
162 			/* Should *never* happen. we warn and carry on */
163 			dev_crit(up->port.dev, "Errata i202: timedout %x\n",
164 				 serial_in(up, UART_LSR));
165 			break;
166 		}
167 		udelay(1);
168 	}
169 }
170 
171 static void omap_8250_get_divisor(struct uart_port *port, unsigned int baud,
172 				  struct omap8250_priv *priv)
173 {
174 	unsigned int uartclk = port->uartclk;
175 	unsigned int div_13, div_16;
176 	unsigned int abs_d13, abs_d16;
177 
178 	/*
179 	 * Old custom speed handling.
180 	 */
181 	if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST) {
182 		priv->quot = port->custom_divisor & 0xffff;
183 		/*
184 		 * I assume that nobody is using this. But hey, if somebody
185 		 * would like to specify the divisor _and_ the mode then the
186 		 * driver is ready and waiting for it.
187 		 */
188 		if (port->custom_divisor & (1 << 16))
189 			priv->mdr1 = UART_OMAP_MDR1_13X_MODE;
190 		else
191 			priv->mdr1 = UART_OMAP_MDR1_16X_MODE;
192 		return;
193 	}
194 	div_13 = DIV_ROUND_CLOSEST(uartclk, 13 * baud);
195 	div_16 = DIV_ROUND_CLOSEST(uartclk, 16 * baud);
196 
197 	if (!div_13)
198 		div_13 = 1;
199 	if (!div_16)
200 		div_16 = 1;
201 
202 	abs_d13 = abs(baud - uartclk / 13 / div_13);
203 	abs_d16 = abs(baud - uartclk / 16 / div_16);
204 
205 	if (abs_d13 >= abs_d16) {
206 		priv->mdr1 = UART_OMAP_MDR1_16X_MODE;
207 		priv->quot = div_16;
208 	} else {
209 		priv->mdr1 = UART_OMAP_MDR1_13X_MODE;
210 		priv->quot = div_13;
211 	}
212 }
213 
214 static void omap8250_update_scr(struct uart_8250_port *up,
215 				struct omap8250_priv *priv)
216 {
217 	u8 old_scr;
218 
219 	old_scr = serial_in(up, UART_OMAP_SCR);
220 	if (old_scr == priv->scr)
221 		return;
222 
223 	/*
224 	 * The manual recommends not to enable the DMA mode selector in the SCR
225 	 * (instead of the FCR) register _and_ selecting the DMA mode as one
226 	 * register write because this may lead to malfunction.
227 	 */
228 	if (priv->scr & OMAP_UART_SCR_DMAMODE_MASK)
229 		serial_out(up, UART_OMAP_SCR,
230 			   priv->scr & ~OMAP_UART_SCR_DMAMODE_MASK);
231 	serial_out(up, UART_OMAP_SCR, priv->scr);
232 }
233 
234 static void omap8250_restore_regs(struct uart_8250_port *up)
235 {
236 	struct omap8250_priv *priv = up->port.private_data;
237 	struct uart_8250_dma	*dma = up->dma;
238 
239 	if (dma && dma->tx_running) {
240 		/*
241 		 * TCSANOW requests the change to occur immediately however if
242 		 * we have a TX-DMA operation in progress then it has been
243 		 * observed that it might stall and never complete. Therefore we
244 		 * delay DMA completes to prevent this hang from happen.
245 		 */
246 		priv->delayed_restore = 1;
247 		return;
248 	}
249 
250 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
251 	serial_out(up, UART_EFR, UART_EFR_ECB);
252 
253 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
254 	serial_out(up, UART_MCR, UART_MCR_TCRTLR);
255 	serial_out(up, UART_FCR, up->fcr);
256 
257 	omap8250_update_scr(up, priv);
258 
259 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
260 
261 	serial_out(up, UART_TI752_TCR, OMAP_UART_TCR_RESTORE(16) |
262 			OMAP_UART_TCR_HALT(52));
263 	serial_out(up, UART_TI752_TLR,
264 		   TRIGGER_TLR_MASK(TX_TRIGGER) << UART_TI752_TLR_TX |
265 		   TRIGGER_TLR_MASK(RX_TRIGGER) << UART_TI752_TLR_RX);
266 
267 	serial_out(up, UART_LCR, 0);
268 
269 	/* drop TCR + TLR access, we setup XON/XOFF later */
270 	serial_out(up, UART_MCR, up->mcr);
271 	serial_out(up, UART_IER, up->ier);
272 
273 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
274 	serial_dl_write(up, priv->quot);
275 
276 	serial_out(up, UART_EFR, priv->efr);
277 
278 	/* Configure flow control */
279 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
280 	serial_out(up, UART_XON1, priv->xon);
281 	serial_out(up, UART_XOFF1, priv->xoff);
282 
283 	serial_out(up, UART_LCR, up->lcr);
284 	/* need mode A for FCR */
285 	if (priv->habit & UART_ERRATA_i202_MDR1_ACCESS)
286 		omap_8250_mdr1_errataset(up, priv);
287 	else
288 		serial_out(up, UART_OMAP_MDR1, priv->mdr1);
289 	up->port.ops->set_mctrl(&up->port, up->port.mctrl);
290 }
291 
292 /*
293  * OMAP can use "CLK / (16 or 13) / div" for baud rate. And then we have have
294  * some differences in how we want to handle flow control.
295  */
296 static void omap_8250_set_termios(struct uart_port *port,
297 				  struct ktermios *termios,
298 				  struct ktermios *old)
299 {
300 	struct uart_8250_port *up =
301 		container_of(port, struct uart_8250_port, port);
302 	struct omap8250_priv *priv = up->port.private_data;
303 	unsigned char cval = 0;
304 	unsigned int baud;
305 
306 	switch (termios->c_cflag & CSIZE) {
307 	case CS5:
308 		cval = UART_LCR_WLEN5;
309 		break;
310 	case CS6:
311 		cval = UART_LCR_WLEN6;
312 		break;
313 	case CS7:
314 		cval = UART_LCR_WLEN7;
315 		break;
316 	default:
317 	case CS8:
318 		cval = UART_LCR_WLEN8;
319 		break;
320 	}
321 
322 	if (termios->c_cflag & CSTOPB)
323 		cval |= UART_LCR_STOP;
324 	if (termios->c_cflag & PARENB)
325 		cval |= UART_LCR_PARITY;
326 	if (!(termios->c_cflag & PARODD))
327 		cval |= UART_LCR_EPAR;
328 	if (termios->c_cflag & CMSPAR)
329 		cval |= UART_LCR_SPAR;
330 
331 	/*
332 	 * Ask the core to calculate the divisor for us.
333 	 */
334 	baud = uart_get_baud_rate(port, termios, old,
335 				  port->uartclk / 16 / 0xffff,
336 				  port->uartclk / 13);
337 	omap_8250_get_divisor(port, baud, priv);
338 
339 	/*
340 	 * Ok, we're now changing the port state. Do it with
341 	 * interrupts disabled.
342 	 */
343 	pm_runtime_get_sync(port->dev);
344 	spin_lock_irq(&port->lock);
345 
346 	/*
347 	 * Update the per-port timeout.
348 	 */
349 	uart_update_timeout(port, termios->c_cflag, baud);
350 
351 	up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
352 	if (termios->c_iflag & INPCK)
353 		up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE;
354 	if (termios->c_iflag & (IGNBRK | PARMRK))
355 		up->port.read_status_mask |= UART_LSR_BI;
356 
357 	/*
358 	 * Characters to ignore
359 	 */
360 	up->port.ignore_status_mask = 0;
361 	if (termios->c_iflag & IGNPAR)
362 		up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
363 	if (termios->c_iflag & IGNBRK) {
364 		up->port.ignore_status_mask |= UART_LSR_BI;
365 		/*
366 		 * If we're ignoring parity and break indicators,
367 		 * ignore overruns too (for real raw support).
368 		 */
369 		if (termios->c_iflag & IGNPAR)
370 			up->port.ignore_status_mask |= UART_LSR_OE;
371 	}
372 
373 	/*
374 	 * ignore all characters if CREAD is not set
375 	 */
376 	if ((termios->c_cflag & CREAD) == 0)
377 		up->port.ignore_status_mask |= UART_LSR_DR;
378 
379 	/*
380 	 * Modem status interrupts
381 	 */
382 	up->ier &= ~UART_IER_MSI;
383 	if (UART_ENABLE_MS(&up->port, termios->c_cflag))
384 		up->ier |= UART_IER_MSI;
385 
386 	up->lcr = cval;
387 	/* Up to here it was mostly serial8250_do_set_termios() */
388 
389 	/*
390 	 * We enable TRIG_GRANU for RX and TX and additionaly we set
391 	 * SCR_TX_EMPTY bit. The result is the following:
392 	 * - RX_TRIGGER amount of bytes in the FIFO will cause an interrupt.
393 	 * - less than RX_TRIGGER number of bytes will also cause an interrupt
394 	 *   once the UART decides that there no new bytes arriving.
395 	 * - Once THRE is enabled, the interrupt will be fired once the FIFO is
396 	 *   empty - the trigger level is ignored here.
397 	 *
398 	 * Once DMA is enabled:
399 	 * - UART will assert the TX DMA line once there is room for TX_TRIGGER
400 	 *   bytes in the TX FIFO. On each assert the DMA engine will move
401 	 *   TX_TRIGGER bytes into the FIFO.
402 	 * - UART will assert the RX DMA line once there are RX_TRIGGER bytes in
403 	 *   the FIFO and move RX_TRIGGER bytes.
404 	 * This is because threshold and trigger values are the same.
405 	 */
406 	up->fcr = UART_FCR_ENABLE_FIFO;
407 	up->fcr |= TRIGGER_FCR_MASK(TX_TRIGGER) << OMAP_UART_FCR_TX_TRIG;
408 	up->fcr |= TRIGGER_FCR_MASK(RX_TRIGGER) << OMAP_UART_FCR_RX_TRIG;
409 
410 	priv->scr = OMAP_UART_SCR_RX_TRIG_GRANU1_MASK | OMAP_UART_SCR_TX_EMPTY |
411 		OMAP_UART_SCR_TX_TRIG_GRANU1_MASK;
412 
413 	if (up->dma)
414 		priv->scr |= OMAP_UART_SCR_DMAMODE_1 |
415 			OMAP_UART_SCR_DMAMODE_CTL;
416 
417 	priv->xon = termios->c_cc[VSTART];
418 	priv->xoff = termios->c_cc[VSTOP];
419 
420 	priv->efr = 0;
421 	up->mcr &= ~(UART_MCR_RTS | UART_MCR_XONANY);
422 	up->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS | UPSTAT_AUTOXOFF);
423 
424 	if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW) {
425 		/* Enable AUTOCTS (autoRTS is enabled when RTS is raised) */
426 		up->port.status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
427 		priv->efr |= UART_EFR_CTS;
428 	} else	if (up->port.flags & UPF_SOFT_FLOW) {
429 		/*
430 		 * IXON Flag:
431 		 * Enable XON/XOFF flow control on input.
432 		 * Receiver compares XON1, XOFF1.
433 		 */
434 		if (termios->c_iflag & IXON)
435 			priv->efr |= OMAP_UART_SW_RX;
436 
437 		/*
438 		 * IXOFF Flag:
439 		 * Enable XON/XOFF flow control on output.
440 		 * Transmit XON1, XOFF1
441 		 */
442 		if (termios->c_iflag & IXOFF) {
443 			up->port.status |= UPSTAT_AUTOXOFF;
444 			priv->efr |= OMAP_UART_SW_TX;
445 		}
446 
447 		/*
448 		 * IXANY Flag:
449 		 * Enable any character to restart output.
450 		 * Operation resumes after receiving any
451 		 * character after recognition of the XOFF character
452 		 */
453 		if (termios->c_iflag & IXANY)
454 			up->mcr |= UART_MCR_XONANY;
455 	}
456 	omap8250_restore_regs(up);
457 
458 	spin_unlock_irq(&up->port.lock);
459 	pm_runtime_mark_last_busy(port->dev);
460 	pm_runtime_put_autosuspend(port->dev);
461 
462 	/* calculate wakeup latency constraint */
463 	priv->calc_latency = USEC_PER_SEC * 64 * 8 / baud;
464 	priv->latency = priv->calc_latency;
465 
466 	schedule_work(&priv->qos_work);
467 
468 	/* Don't rewrite B0 */
469 	if (tty_termios_baud_rate(termios))
470 		tty_termios_encode_baud_rate(termios, baud, baud);
471 }
472 
473 /* same as 8250 except that we may have extra flow bits set in EFR */
474 static void omap_8250_pm(struct uart_port *port, unsigned int state,
475 			 unsigned int oldstate)
476 {
477 	struct uart_8250_port *up = up_to_u8250p(port);
478 	u8 efr;
479 
480 	pm_runtime_get_sync(port->dev);
481 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
482 	efr = serial_in(up, UART_EFR);
483 	serial_out(up, UART_EFR, efr | UART_EFR_ECB);
484 	serial_out(up, UART_LCR, 0);
485 
486 	serial_out(up, UART_IER, (state != 0) ? UART_IERX_SLEEP : 0);
487 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
488 	serial_out(up, UART_EFR, efr);
489 	serial_out(up, UART_LCR, 0);
490 
491 	pm_runtime_mark_last_busy(port->dev);
492 	pm_runtime_put_autosuspend(port->dev);
493 }
494 
495 static void omap_serial_fill_features_erratas(struct uart_8250_port *up,
496 					      struct omap8250_priv *priv)
497 {
498 	u32 mvr, scheme;
499 	u16 revision, major, minor;
500 
501 	mvr = uart_read(up, UART_OMAP_MVER);
502 
503 	/* Check revision register scheme */
504 	scheme = mvr >> OMAP_UART_MVR_SCHEME_SHIFT;
505 
506 	switch (scheme) {
507 	case 0: /* Legacy Scheme: OMAP2/3 */
508 		/* MINOR_REV[0:4], MAJOR_REV[4:7] */
509 		major = (mvr & OMAP_UART_LEGACY_MVR_MAJ_MASK) >>
510 			OMAP_UART_LEGACY_MVR_MAJ_SHIFT;
511 		minor = (mvr & OMAP_UART_LEGACY_MVR_MIN_MASK);
512 		break;
513 	case 1:
514 		/* New Scheme: OMAP4+ */
515 		/* MINOR_REV[0:5], MAJOR_REV[8:10] */
516 		major = (mvr & OMAP_UART_MVR_MAJ_MASK) >>
517 			OMAP_UART_MVR_MAJ_SHIFT;
518 		minor = (mvr & OMAP_UART_MVR_MIN_MASK);
519 		break;
520 	default:
521 		dev_warn(up->port.dev,
522 			 "Unknown revision, defaulting to highest\n");
523 		/* highest possible revision */
524 		major = 0xff;
525 		minor = 0xff;
526 	}
527 	/* normalize revision for the driver */
528 	revision = UART_BUILD_REVISION(major, minor);
529 
530 	switch (revision) {
531 	case OMAP_UART_REV_46:
532 		priv->habit = UART_ERRATA_i202_MDR1_ACCESS;
533 		break;
534 	case OMAP_UART_REV_52:
535 		priv->habit = UART_ERRATA_i202_MDR1_ACCESS |
536 				OMAP_UART_WER_HAS_TX_WAKEUP;
537 		break;
538 	case OMAP_UART_REV_63:
539 		priv->habit = UART_ERRATA_i202_MDR1_ACCESS |
540 			OMAP_UART_WER_HAS_TX_WAKEUP;
541 		break;
542 	default:
543 		break;
544 	}
545 }
546 
547 static void omap8250_uart_qos_work(struct work_struct *work)
548 {
549 	struct omap8250_priv *priv;
550 
551 	priv = container_of(work, struct omap8250_priv, qos_work);
552 	pm_qos_update_request(&priv->pm_qos_request, priv->latency);
553 }
554 
555 static irqreturn_t omap_wake_irq(int irq, void *dev_id)
556 {
557 	struct uart_port *port = dev_id;
558 	int ret;
559 
560 	ret = port->handle_irq(port);
561 	if (ret)
562 		return IRQ_HANDLED;
563 	return IRQ_NONE;
564 }
565 
566 static int omap_8250_startup(struct uart_port *port)
567 {
568 	struct uart_8250_port *up =
569 		container_of(port, struct uart_8250_port, port);
570 	struct omap8250_priv *priv = port->private_data;
571 
572 	int ret;
573 
574 	if (priv->wakeirq) {
575 		ret = request_irq(priv->wakeirq, omap_wake_irq,
576 				  port->irqflags, "uart wakeup irq", port);
577 		if (ret)
578 			return ret;
579 		disable_irq(priv->wakeirq);
580 	}
581 
582 	pm_runtime_get_sync(port->dev);
583 
584 	ret = serial8250_do_startup(port);
585 	if (ret)
586 		goto err;
587 
588 #ifdef CONFIG_PM
589 	up->capabilities |= UART_CAP_RPM;
590 #endif
591 
592 	/* Enable module level wake up */
593 	priv->wer = OMAP_UART_WER_MOD_WKUP;
594 	if (priv->habit & OMAP_UART_WER_HAS_TX_WAKEUP)
595 		priv->wer |= OMAP_UART_TX_WAKEUP_EN;
596 	serial_out(up, UART_OMAP_WER, priv->wer);
597 
598 	if (up->dma)
599 		up->dma->rx_dma(up, 0);
600 
601 	pm_runtime_mark_last_busy(port->dev);
602 	pm_runtime_put_autosuspend(port->dev);
603 	return 0;
604 err:
605 	pm_runtime_mark_last_busy(port->dev);
606 	pm_runtime_put_autosuspend(port->dev);
607 	if (priv->wakeirq)
608 		free_irq(priv->wakeirq, port);
609 	return ret;
610 }
611 
612 static void omap_8250_shutdown(struct uart_port *port)
613 {
614 	struct uart_8250_port *up =
615 		container_of(port, struct uart_8250_port, port);
616 	struct omap8250_priv *priv = port->private_data;
617 
618 	flush_work(&priv->qos_work);
619 	if (up->dma)
620 		up->dma->rx_dma(up, UART_IIR_RX_TIMEOUT);
621 
622 	pm_runtime_get_sync(port->dev);
623 
624 	serial_out(up, UART_OMAP_WER, 0);
625 	serial8250_do_shutdown(port);
626 
627 	pm_runtime_mark_last_busy(port->dev);
628 	pm_runtime_put_autosuspend(port->dev);
629 
630 	if (priv->wakeirq)
631 		free_irq(priv->wakeirq, port);
632 }
633 
634 static void omap_8250_throttle(struct uart_port *port)
635 {
636 	unsigned long flags;
637 	struct uart_8250_port *up =
638 		container_of(port, struct uart_8250_port, port);
639 
640 	pm_runtime_get_sync(port->dev);
641 
642 	spin_lock_irqsave(&port->lock, flags);
643 	up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
644 	serial_out(up, UART_IER, up->ier);
645 	spin_unlock_irqrestore(&port->lock, flags);
646 
647 	pm_runtime_mark_last_busy(port->dev);
648 	pm_runtime_put_autosuspend(port->dev);
649 }
650 
651 static void omap_8250_unthrottle(struct uart_port *port)
652 {
653 	unsigned long flags;
654 	struct uart_8250_port *up =
655 		container_of(port, struct uart_8250_port, port);
656 
657 	pm_runtime_get_sync(port->dev);
658 
659 	spin_lock_irqsave(&port->lock, flags);
660 	up->ier |= UART_IER_RLSI | UART_IER_RDI;
661 	serial_out(up, UART_IER, up->ier);
662 	spin_unlock_irqrestore(&port->lock, flags);
663 
664 	pm_runtime_mark_last_busy(port->dev);
665 	pm_runtime_put_autosuspend(port->dev);
666 }
667 
668 #ifdef CONFIG_SERIAL_8250_DMA
669 static int omap_8250_rx_dma(struct uart_8250_port *p, unsigned int iir);
670 
671 static void __dma_rx_do_complete(struct uart_8250_port *p, bool error)
672 {
673 	struct uart_8250_dma    *dma = p->dma;
674 	struct tty_port         *tty_port = &p->port.state->port;
675 	struct dma_tx_state     state;
676 	int                     count;
677 
678 	dma_sync_single_for_cpu(dma->rxchan->device->dev, dma->rx_addr,
679 				dma->rx_size, DMA_FROM_DEVICE);
680 
681 	dma->rx_running = 0;
682 	dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state);
683 	dmaengine_terminate_all(dma->rxchan);
684 
685 	count = dma->rx_size - state.residue;
686 
687 	tty_insert_flip_string(tty_port, dma->rx_buf, count);
688 	p->port.icount.rx += count;
689 	if (!error)
690 		omap_8250_rx_dma(p, 0);
691 
692 	tty_flip_buffer_push(tty_port);
693 }
694 
695 static void __dma_rx_complete(void *param)
696 {
697 	__dma_rx_do_complete(param, false);
698 }
699 
700 static int omap_8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
701 {
702 	struct uart_8250_dma            *dma = p->dma;
703 	struct dma_async_tx_descriptor  *desc;
704 
705 	switch (iir & 0x3f) {
706 	case UART_IIR_RLSI:
707 		/* 8250_core handles errors and break interrupts */
708 		if (dma->rx_running) {
709 			dmaengine_pause(dma->rxchan);
710 			__dma_rx_do_complete(p, true);
711 		}
712 		return -EIO;
713 	case UART_IIR_RX_TIMEOUT:
714 		/*
715 		 * If RCVR FIFO trigger level was not reached, complete the
716 		 * transfer and let 8250_core copy the remaining data.
717 		 */
718 		if (dma->rx_running) {
719 			dmaengine_pause(dma->rxchan);
720 			__dma_rx_do_complete(p, true);
721 		}
722 		return -ETIMEDOUT;
723 	case UART_IIR_RDI:
724 		/*
725 		 * The OMAP UART is a special BEAST. If we receive RDI we _have_
726 		 * a DMA transfer programmed but it didn't work. One reason is
727 		 * that we were too slow and there were too many bytes in the
728 		 * FIFO, the UART counted wrong and never kicked the DMA engine
729 		 * to do anything. That means once we receive RDI on OMAP then
730 		 * the DMA won't do anything soon so we have to cancel the DMA
731 		 * transfer and purge the FIFO manually.
732 		 */
733 		if (dma->rx_running) {
734 			dmaengine_pause(dma->rxchan);
735 			__dma_rx_do_complete(p, true);
736 		}
737 		return -ETIMEDOUT;
738 
739 	default:
740 		break;
741 	}
742 
743 	if (dma->rx_running)
744 		return 0;
745 
746 	desc = dmaengine_prep_slave_single(dma->rxchan, dma->rx_addr,
747 					   dma->rx_size, DMA_DEV_TO_MEM,
748 					   DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
749 	if (!desc)
750 		return -EBUSY;
751 
752 	dma->rx_running = 1;
753 	desc->callback = __dma_rx_complete;
754 	desc->callback_param = p;
755 
756 	dma->rx_cookie = dmaengine_submit(desc);
757 
758 	dma_sync_single_for_device(dma->rxchan->device->dev, dma->rx_addr,
759 				   dma->rx_size, DMA_FROM_DEVICE);
760 
761 	dma_async_issue_pending(dma->rxchan);
762 	return 0;
763 }
764 
765 static int omap_8250_tx_dma(struct uart_8250_port *p);
766 
767 static void omap_8250_dma_tx_complete(void *param)
768 {
769 	struct uart_8250_port	*p = param;
770 	struct uart_8250_dma	*dma = p->dma;
771 	struct circ_buf		*xmit = &p->port.state->xmit;
772 	unsigned long		flags;
773 	bool			en_thri = false;
774 	struct omap8250_priv	*priv = p->port.private_data;
775 
776 	dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr,
777 				UART_XMIT_SIZE, DMA_TO_DEVICE);
778 
779 	spin_lock_irqsave(&p->port.lock, flags);
780 
781 	dma->tx_running = 0;
782 
783 	xmit->tail += dma->tx_size;
784 	xmit->tail &= UART_XMIT_SIZE - 1;
785 	p->port.icount.tx += dma->tx_size;
786 
787 	if (priv->delayed_restore) {
788 		priv->delayed_restore = 0;
789 		omap8250_restore_regs(p);
790 	}
791 
792 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
793 		uart_write_wakeup(&p->port);
794 
795 	if (!uart_circ_empty(xmit) && !uart_tx_stopped(&p->port)) {
796 		int ret;
797 
798 		ret = omap_8250_tx_dma(p);
799 		if (ret)
800 			en_thri = true;
801 
802 	} else if (p->capabilities & UART_CAP_RPM) {
803 		en_thri = true;
804 	}
805 
806 	if (en_thri) {
807 		dma->tx_err = 1;
808 		p->ier |= UART_IER_THRI;
809 		serial_port_out(&p->port, UART_IER, p->ier);
810 	}
811 
812 	spin_unlock_irqrestore(&p->port.lock, flags);
813 }
814 
815 static int omap_8250_tx_dma(struct uart_8250_port *p)
816 {
817 	struct uart_8250_dma		*dma = p->dma;
818 	struct omap8250_priv		*priv = p->port.private_data;
819 	struct circ_buf			*xmit = &p->port.state->xmit;
820 	struct dma_async_tx_descriptor	*desc;
821 	unsigned int	skip_byte = 0;
822 	int ret;
823 
824 	if (dma->tx_running)
825 		return 0;
826 	if (uart_tx_stopped(&p->port) || uart_circ_empty(xmit)) {
827 
828 		/*
829 		 * Even if no data, we need to return an error for the two cases
830 		 * below so serial8250_tx_chars() is invoked and properly clears
831 		 * THRI and/or runtime suspend.
832 		 */
833 		if (dma->tx_err || p->capabilities & UART_CAP_RPM) {
834 			ret = -EBUSY;
835 			goto err;
836 		}
837 		if (p->ier & UART_IER_THRI) {
838 			p->ier &= ~UART_IER_THRI;
839 			serial_out(p, UART_IER, p->ier);
840 		}
841 		return 0;
842 	}
843 
844 	dma->tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
845 	if (priv->habit & OMAP_DMA_TX_KICK) {
846 		u8 tx_lvl;
847 
848 		/*
849 		 * We need to put the first byte into the FIFO in order to start
850 		 * the DMA transfer. For transfers smaller than four bytes we
851 		 * don't bother doing DMA at all. It seem not matter if there
852 		 * are still bytes in the FIFO from the last transfer (in case
853 		 * we got here directly from omap_8250_dma_tx_complete()). Bytes
854 		 * leaving the FIFO seem not to trigger the DMA transfer. It is
855 		 * really the byte that we put into the FIFO.
856 		 * If the FIFO is already full then we most likely got here from
857 		 * omap_8250_dma_tx_complete(). And this means the DMA engine
858 		 * just completed its work. We don't have to wait the complete
859 		 * 86us at 115200,8n1 but around 60us (not to mention lower
860 		 * baudrates). So in that case we take the interrupt and try
861 		 * again with an empty FIFO.
862 		 */
863 		tx_lvl = serial_in(p, UART_OMAP_TX_LVL);
864 		if (tx_lvl == p->tx_loadsz) {
865 			ret = -EBUSY;
866 			goto err;
867 		}
868 		if (dma->tx_size < 4) {
869 			ret = -EINVAL;
870 			goto err;
871 		}
872 		skip_byte = 1;
873 	}
874 
875 	desc = dmaengine_prep_slave_single(dma->txchan,
876 			dma->tx_addr + xmit->tail + skip_byte,
877 			dma->tx_size - skip_byte, DMA_MEM_TO_DEV,
878 			DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
879 	if (!desc) {
880 		ret = -EBUSY;
881 		goto err;
882 	}
883 
884 	dma->tx_running = 1;
885 
886 	desc->callback = omap_8250_dma_tx_complete;
887 	desc->callback_param = p;
888 
889 	dma->tx_cookie = dmaengine_submit(desc);
890 
891 	dma_sync_single_for_device(dma->txchan->device->dev, dma->tx_addr,
892 				   UART_XMIT_SIZE, DMA_TO_DEVICE);
893 
894 	dma_async_issue_pending(dma->txchan);
895 	if (dma->tx_err)
896 		dma->tx_err = 0;
897 
898 	if (p->ier & UART_IER_THRI) {
899 		p->ier &= ~UART_IER_THRI;
900 		serial_out(p, UART_IER, p->ier);
901 	}
902 	if (skip_byte)
903 		serial_out(p, UART_TX, xmit->buf[xmit->tail]);
904 	return 0;
905 err:
906 	dma->tx_err = 1;
907 	return ret;
908 }
909 
910 /*
911  * This is mostly serial8250_handle_irq(). We have a slightly different DMA
912  * hoook for RX/TX and need different logic for them in the ISR. Therefore we
913  * use the default routine in the non-DMA case and this one for with DMA.
914  */
915 static int omap_8250_dma_handle_irq(struct uart_port *port)
916 {
917 	struct uart_8250_port *up = up_to_u8250p(port);
918 	unsigned char status;
919 	unsigned long flags;
920 	u8 iir;
921 	int dma_err = 0;
922 
923 	serial8250_rpm_get(up);
924 
925 	iir = serial_port_in(port, UART_IIR);
926 	if (iir & UART_IIR_NO_INT) {
927 		serial8250_rpm_put(up);
928 		return 0;
929 	}
930 
931 	spin_lock_irqsave(&port->lock, flags);
932 
933 	status = serial_port_in(port, UART_LSR);
934 
935 	if (status & (UART_LSR_DR | UART_LSR_BI)) {
936 
937 		dma_err = omap_8250_rx_dma(up, iir);
938 		if (dma_err) {
939 			status = serial8250_rx_chars(up, status);
940 			omap_8250_rx_dma(up, 0);
941 		}
942 	}
943 	serial8250_modem_status(up);
944 	if (status & UART_LSR_THRE && up->dma->tx_err) {
945 		if (uart_tx_stopped(&up->port) ||
946 		    uart_circ_empty(&up->port.state->xmit)) {
947 			up->dma->tx_err = 0;
948 			serial8250_tx_chars(up);
949 		} else  {
950 			/*
951 			 * try again due to an earlier failer which
952 			 * might have been resolved by now.
953 			 */
954 			dma_err = omap_8250_tx_dma(up);
955 			if (dma_err)
956 				serial8250_tx_chars(up);
957 		}
958 	}
959 
960 	spin_unlock_irqrestore(&port->lock, flags);
961 	serial8250_rpm_put(up);
962 	return 1;
963 }
964 
965 static bool the_no_dma_filter_fn(struct dma_chan *chan, void *param)
966 {
967 	return false;
968 }
969 
970 #else
971 
972 static inline int omap_8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
973 {
974 	return -EINVAL;
975 }
976 #endif
977 
978 static int omap8250_probe(struct platform_device *pdev)
979 {
980 	struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
981 	struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
982 	struct omap8250_priv *priv;
983 	struct uart_8250_port up;
984 	int ret;
985 	void __iomem *membase;
986 
987 	if (!regs || !irq) {
988 		dev_err(&pdev->dev, "missing registers or irq\n");
989 		return -EINVAL;
990 	}
991 
992 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
993 	if (!priv)
994 		return -ENOMEM;
995 
996 	membase = devm_ioremap_nocache(&pdev->dev, regs->start,
997 				       resource_size(regs));
998 	if (!membase)
999 		return -ENODEV;
1000 
1001 	memset(&up, 0, sizeof(up));
1002 	up.port.dev = &pdev->dev;
1003 	up.port.mapbase = regs->start;
1004 	up.port.membase = membase;
1005 	up.port.irq = irq->start;
1006 	/*
1007 	 * It claims to be 16C750 compatible however it is a little different.
1008 	 * It has EFR and has no FCR7_64byte bit. The AFE (which it claims to
1009 	 * have) is enabled via EFR instead of MCR. The type is set here 8250
1010 	 * just to get things going. UNKNOWN does not work for a few reasons and
1011 	 * we don't need our own type since we don't use 8250's set_termios()
1012 	 * or pm callback.
1013 	 */
1014 	up.port.type = PORT_8250;
1015 	up.port.iotype = UPIO_MEM;
1016 	up.port.flags = UPF_FIXED_PORT | UPF_FIXED_TYPE | UPF_SOFT_FLOW |
1017 		UPF_HARD_FLOW;
1018 	up.port.private_data = priv;
1019 
1020 	up.port.regshift = 2;
1021 	up.port.fifosize = 64;
1022 	up.tx_loadsz = 64;
1023 	up.capabilities = UART_CAP_FIFO;
1024 #ifdef CONFIG_PM
1025 	/*
1026 	 * Runtime PM is mostly transparent. However to do it right we need to a
1027 	 * TX empty interrupt before we can put the device to auto idle. So if
1028 	 * PM is not enabled we don't add that flag and can spare that one extra
1029 	 * interrupt in the TX path.
1030 	 */
1031 	up.capabilities |= UART_CAP_RPM;
1032 #endif
1033 	up.port.set_termios = omap_8250_set_termios;
1034 	up.port.set_mctrl = omap8250_set_mctrl;
1035 	up.port.pm = omap_8250_pm;
1036 	up.port.startup = omap_8250_startup;
1037 	up.port.shutdown = omap_8250_shutdown;
1038 	up.port.throttle = omap_8250_throttle;
1039 	up.port.unthrottle = omap_8250_unthrottle;
1040 
1041 	if (pdev->dev.of_node) {
1042 		ret = of_alias_get_id(pdev->dev.of_node, "serial");
1043 
1044 		of_property_read_u32(pdev->dev.of_node, "clock-frequency",
1045 				     &up.port.uartclk);
1046 		priv->wakeirq = irq_of_parse_and_map(pdev->dev.of_node, 1);
1047 	} else {
1048 		ret = pdev->id;
1049 	}
1050 	if (ret < 0) {
1051 		dev_err(&pdev->dev, "failed to get alias/pdev id\n");
1052 		return ret;
1053 	}
1054 	up.port.line = ret;
1055 
1056 	if (!up.port.uartclk) {
1057 		up.port.uartclk = DEFAULT_CLK_SPEED;
1058 		dev_warn(&pdev->dev,
1059 			 "No clock speed specified: using default: %d\n",
1060 			 DEFAULT_CLK_SPEED);
1061 	}
1062 
1063 	priv->latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;
1064 	priv->calc_latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;
1065 	pm_qos_add_request(&priv->pm_qos_request, PM_QOS_CPU_DMA_LATENCY,
1066 			   priv->latency);
1067 	INIT_WORK(&priv->qos_work, omap8250_uart_qos_work);
1068 
1069 	device_init_wakeup(&pdev->dev, true);
1070 	pm_runtime_use_autosuspend(&pdev->dev);
1071 	pm_runtime_set_autosuspend_delay(&pdev->dev, -1);
1072 
1073 	pm_runtime_irq_safe(&pdev->dev);
1074 	pm_runtime_enable(&pdev->dev);
1075 
1076 	pm_runtime_get_sync(&pdev->dev);
1077 
1078 	omap_serial_fill_features_erratas(&up, priv);
1079 #ifdef CONFIG_SERIAL_8250_DMA
1080 	if (pdev->dev.of_node) {
1081 		/*
1082 		 * Oh DMA support. If there are no DMA properties in the DT then
1083 		 * we will fall back to a generic DMA channel which does not
1084 		 * really work here. To ensure that we do not get a generic DMA
1085 		 * channel assigned, we have the the_no_dma_filter_fn() here.
1086 		 * To avoid "failed to request DMA" messages we check for DMA
1087 		 * properties in DT.
1088 		 */
1089 		ret = of_property_count_strings(pdev->dev.of_node, "dma-names");
1090 		if (ret == 2) {
1091 			up.dma = &priv->omap8250_dma;
1092 			up.port.handle_irq = omap_8250_dma_handle_irq;
1093 			priv->omap8250_dma.fn = the_no_dma_filter_fn;
1094 			priv->omap8250_dma.tx_dma = omap_8250_tx_dma;
1095 			priv->omap8250_dma.rx_dma = omap_8250_rx_dma;
1096 			priv->omap8250_dma.rx_size = RX_TRIGGER;
1097 			priv->omap8250_dma.rxconf.src_maxburst = RX_TRIGGER;
1098 			priv->omap8250_dma.txconf.dst_maxburst = TX_TRIGGER;
1099 
1100 			if (of_machine_is_compatible("ti,am33xx"))
1101 				priv->habit |= OMAP_DMA_TX_KICK;
1102 		}
1103 	}
1104 #endif
1105 	ret = serial8250_register_8250_port(&up);
1106 	if (ret < 0) {
1107 		dev_err(&pdev->dev, "unable to register 8250 port\n");
1108 		goto err;
1109 	}
1110 	priv->line = ret;
1111 	platform_set_drvdata(pdev, priv);
1112 	pm_runtime_mark_last_busy(&pdev->dev);
1113 	pm_runtime_put_autosuspend(&pdev->dev);
1114 	return 0;
1115 err:
1116 	pm_runtime_put(&pdev->dev);
1117 	pm_runtime_disable(&pdev->dev);
1118 	return ret;
1119 }
1120 
1121 static int omap8250_remove(struct platform_device *pdev)
1122 {
1123 	struct omap8250_priv *priv = platform_get_drvdata(pdev);
1124 
1125 	pm_runtime_put_sync(&pdev->dev);
1126 	pm_runtime_disable(&pdev->dev);
1127 	serial8250_unregister_port(priv->line);
1128 	pm_qos_remove_request(&priv->pm_qos_request);
1129 	device_init_wakeup(&pdev->dev, false);
1130 	return 0;
1131 }
1132 
1133 #ifdef CONFIG_PM
1134 
1135 static inline void omap8250_enable_wakeirq(struct omap8250_priv *priv,
1136 					   bool enable)
1137 {
1138 	if (!priv->wakeirq)
1139 		return;
1140 
1141 	if (enable)
1142 		enable_irq(priv->wakeirq);
1143 	else
1144 		disable_irq_nosync(priv->wakeirq);
1145 }
1146 
1147 static void omap8250_enable_wakeup(struct omap8250_priv *priv,
1148 				   bool enable)
1149 {
1150 	if (enable == priv->wakeups_enabled)
1151 		return;
1152 
1153 	omap8250_enable_wakeirq(priv, enable);
1154 	priv->wakeups_enabled = enable;
1155 }
1156 #endif
1157 
1158 #ifdef CONFIG_PM_SLEEP
1159 static int omap8250_prepare(struct device *dev)
1160 {
1161 	struct omap8250_priv *priv = dev_get_drvdata(dev);
1162 
1163 	if (!priv)
1164 		return 0;
1165 	priv->is_suspending = true;
1166 	return 0;
1167 }
1168 
1169 static void omap8250_complete(struct device *dev)
1170 {
1171 	struct omap8250_priv *priv = dev_get_drvdata(dev);
1172 
1173 	if (!priv)
1174 		return;
1175 	priv->is_suspending = false;
1176 }
1177 
1178 static int omap8250_suspend(struct device *dev)
1179 {
1180 	struct omap8250_priv *priv = dev_get_drvdata(dev);
1181 
1182 	serial8250_suspend_port(priv->line);
1183 	flush_work(&priv->qos_work);
1184 
1185 	if (device_may_wakeup(dev))
1186 		omap8250_enable_wakeup(priv, true);
1187 	else
1188 		omap8250_enable_wakeup(priv, false);
1189 	return 0;
1190 }
1191 
1192 static int omap8250_resume(struct device *dev)
1193 {
1194 	struct omap8250_priv *priv = dev_get_drvdata(dev);
1195 
1196 	if (device_may_wakeup(dev))
1197 		omap8250_enable_wakeup(priv, false);
1198 
1199 	serial8250_resume_port(priv->line);
1200 	return 0;
1201 }
1202 #else
1203 #define omap8250_prepare NULL
1204 #define omap8250_complete NULL
1205 #endif
1206 
1207 #ifdef CONFIG_PM
1208 static int omap8250_lost_context(struct uart_8250_port *up)
1209 {
1210 	u32 val;
1211 
1212 	val = serial_in(up, UART_OMAP_MDR1);
1213 	/*
1214 	 * If we lose context, then MDR1 is set to its reset value which is
1215 	 * UART_OMAP_MDR1_DISABLE. After set_termios() we set it either to 13x
1216 	 * or 16x but never to disable again.
1217 	 */
1218 	if (val == UART_OMAP_MDR1_DISABLE)
1219 		return 1;
1220 	return 0;
1221 }
1222 
1223 static int omap8250_runtime_suspend(struct device *dev)
1224 {
1225 	struct omap8250_priv *priv = dev_get_drvdata(dev);
1226 	struct uart_8250_port *up;
1227 
1228 	up = serial8250_get_port(priv->line);
1229 	/*
1230 	 * When using 'no_console_suspend', the console UART must not be
1231 	 * suspended. Since driver suspend is managed by runtime suspend,
1232 	 * preventing runtime suspend (by returning error) will keep device
1233 	 * active during suspend.
1234 	 */
1235 	if (priv->is_suspending && !console_suspend_enabled) {
1236 		if (uart_console(&up->port))
1237 			return -EBUSY;
1238 	}
1239 
1240 	omap8250_enable_wakeup(priv, true);
1241 	if (up->dma)
1242 		omap_8250_rx_dma(up, UART_IIR_RX_TIMEOUT);
1243 
1244 	priv->latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;
1245 	schedule_work(&priv->qos_work);
1246 
1247 	return 0;
1248 }
1249 
1250 static int omap8250_runtime_resume(struct device *dev)
1251 {
1252 	struct omap8250_priv *priv = dev_get_drvdata(dev);
1253 	struct uart_8250_port *up;
1254 	int loss_cntx;
1255 
1256 	/* In case runtime-pm tries this before we are setup */
1257 	if (!priv)
1258 		return 0;
1259 
1260 	up = serial8250_get_port(priv->line);
1261 	omap8250_enable_wakeup(priv, false);
1262 	loss_cntx = omap8250_lost_context(up);
1263 
1264 	if (loss_cntx)
1265 		omap8250_restore_regs(up);
1266 
1267 	if (up->dma)
1268 		omap_8250_rx_dma(up, 0);
1269 
1270 	priv->latency = priv->calc_latency;
1271 	schedule_work(&priv->qos_work);
1272 	return 0;
1273 }
1274 #endif
1275 
1276 #ifdef CONFIG_SERIAL_8250_OMAP_TTYO_FIXUP
1277 static int __init omap8250_console_fixup(void)
1278 {
1279 	char *omap_str;
1280 	char *options;
1281 	u8 idx;
1282 
1283 	if (strstr(boot_command_line, "console=ttyS"))
1284 		/* user set a ttyS based name for the console */
1285 		return 0;
1286 
1287 	omap_str = strstr(boot_command_line, "console=ttyO");
1288 	if (!omap_str)
1289 		/* user did not set ttyO based console, so we don't care */
1290 		return 0;
1291 
1292 	omap_str += 12;
1293 	if ('0' <= *omap_str && *omap_str <= '9')
1294 		idx = *omap_str - '0';
1295 	else
1296 		return 0;
1297 
1298 	omap_str++;
1299 	if (omap_str[0] == ',') {
1300 		omap_str++;
1301 		options = omap_str;
1302 	} else {
1303 		options = NULL;
1304 	}
1305 
1306 	add_preferred_console("ttyS", idx, options);
1307 	pr_err("WARNING: Your 'console=ttyO%d' has been replaced by 'ttyS%d'\n",
1308 	       idx, idx);
1309 	pr_err("This ensures that you still see kernel messages. Please\n");
1310 	pr_err("update your kernel commandline.\n");
1311 	return 0;
1312 }
1313 console_initcall(omap8250_console_fixup);
1314 #endif
1315 
1316 static const struct dev_pm_ops omap8250_dev_pm_ops = {
1317 	SET_SYSTEM_SLEEP_PM_OPS(omap8250_suspend, omap8250_resume)
1318 	SET_RUNTIME_PM_OPS(omap8250_runtime_suspend,
1319 			   omap8250_runtime_resume, NULL)
1320 	.prepare        = omap8250_prepare,
1321 	.complete       = omap8250_complete,
1322 };
1323 
1324 static const struct of_device_id omap8250_dt_ids[] = {
1325 	{ .compatible = "ti,omap2-uart" },
1326 	{ .compatible = "ti,omap3-uart" },
1327 	{ .compatible = "ti,omap4-uart" },
1328 	{},
1329 };
1330 MODULE_DEVICE_TABLE(of, omap8250_dt_ids);
1331 
1332 static struct platform_driver omap8250_platform_driver = {
1333 	.driver = {
1334 		.name		= "omap8250",
1335 		.pm		= &omap8250_dev_pm_ops,
1336 		.of_match_table = omap8250_dt_ids,
1337 	},
1338 	.probe			= omap8250_probe,
1339 	.remove			= omap8250_remove,
1340 };
1341 module_platform_driver(omap8250_platform_driver);
1342 
1343 MODULE_AUTHOR("Sebastian Andrzej Siewior");
1344 MODULE_DESCRIPTION("OMAP 8250 Driver");
1345 MODULE_LICENSE("GPL v2");
1346