xref: /linux/drivers/tty/serial/8250/8250_dw.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Synopsys DesignWare 8250 driver.
4  *
5  * Copyright 2011 Picochip, Jamie Iles.
6  * Copyright 2013 Intel Corporation
7  *
8  * The Synopsys DesignWare 8250 has an extra feature whereby it detects if the
9  * LCR is written whilst busy.  If it is, then a busy detect interrupt is
10  * raised, the LCR needs to be rewritten and the uart status register read.
11  */
12 #include <linux/clk.h>
13 #include <linux/delay.h>
14 #include <linux/device.h>
15 #include <linux/io.h>
16 #include <linux/mod_devicetable.h>
17 #include <linux/module.h>
18 #include <linux/notifier.h>
19 #include <linux/platform_device.h>
20 #include <linux/pm_runtime.h>
21 #include <linux/property.h>
22 #include <linux/reset.h>
23 #include <linux/slab.h>
24 #include <linux/workqueue.h>
25 
26 #include <asm/byteorder.h>
27 
28 #include <linux/serial_8250.h>
29 #include <linux/serial_reg.h>
30 
31 #include "8250_dwlib.h"
32 
33 /* Offsets for the DesignWare specific registers */
34 #define DW_UART_USR	0x1f /* UART Status Register */
35 #define DW_UART_DMASA	0xa8 /* DMA Software Ack */
36 
37 #define OCTEON_UART_USR	0x27 /* UART Status Register */
38 
39 #define RZN1_UART_TDMACR 0x10c /* DMA Control Register Transmit Mode */
40 #define RZN1_UART_RDMACR 0x110 /* DMA Control Register Receive Mode */
41 
42 /* DesignWare specific register fields */
43 #define DW_UART_MCR_SIRE		BIT(6)
44 
45 /* Renesas specific register fields */
46 #define RZN1_UART_xDMACR_DMA_EN		BIT(0)
47 #define RZN1_UART_xDMACR_1_WORD_BURST	(0 << 1)
48 #define RZN1_UART_xDMACR_4_WORD_BURST	(1 << 1)
49 #define RZN1_UART_xDMACR_8_WORD_BURST	(2 << 1)
50 #define RZN1_UART_xDMACR_BLK_SZ(x)	((x) << 3)
51 
52 /* Quirks */
53 #define DW_UART_QUIRK_OCTEON		BIT(0)
54 #define DW_UART_QUIRK_ARMADA_38X	BIT(1)
55 #define DW_UART_QUIRK_SKIP_SET_RATE	BIT(2)
56 #define DW_UART_QUIRK_IS_DMA_FC		BIT(3)
57 #define DW_UART_QUIRK_APMC0D08		BIT(4)
58 #define DW_UART_QUIRK_CPR_VALUE		BIT(5)
59 
60 struct dw8250_platform_data {
61 	u8 usr_reg;
62 	u32 cpr_value;
63 	unsigned int quirks;
64 };
65 
66 struct dw8250_data {
67 	struct dw8250_port_data	data;
68 	const struct dw8250_platform_data *pdata;
69 
70 	int			msr_mask_on;
71 	int			msr_mask_off;
72 	struct clk		*clk;
73 	struct clk		*pclk;
74 	struct notifier_block	clk_notifier;
75 	struct work_struct	clk_work;
76 	struct reset_control	*rst;
77 
78 	unsigned int		skip_autocfg:1;
79 	unsigned int		uart_16550_compatible:1;
80 };
81 
82 static inline struct dw8250_data *to_dw8250_data(struct dw8250_port_data *data)
83 {
84 	return container_of(data, struct dw8250_data, data);
85 }
86 
87 static inline struct dw8250_data *clk_to_dw8250_data(struct notifier_block *nb)
88 {
89 	return container_of(nb, struct dw8250_data, clk_notifier);
90 }
91 
92 static inline struct dw8250_data *work_to_dw8250_data(struct work_struct *work)
93 {
94 	return container_of(work, struct dw8250_data, clk_work);
95 }
96 
97 static inline int dw8250_modify_msr(struct uart_port *p, int offset, int value)
98 {
99 	struct dw8250_data *d = to_dw8250_data(p->private_data);
100 
101 	/* Override any modem control signals if needed */
102 	if (offset == UART_MSR) {
103 		value |= d->msr_mask_on;
104 		value &= ~d->msr_mask_off;
105 	}
106 
107 	return value;
108 }
109 
110 static void dw8250_force_idle(struct uart_port *p)
111 {
112 	struct uart_8250_port *up = up_to_u8250p(p);
113 	unsigned int lsr;
114 
115 	serial8250_clear_and_reinit_fifos(up);
116 
117 	/*
118 	 * With PSLVERR_RESP_EN parameter set to 1, the device generates an
119 	 * error response when an attempt to read an empty RBR with FIFO
120 	 * enabled.
121 	 */
122 	if (up->fcr & UART_FCR_ENABLE_FIFO) {
123 		lsr = p->serial_in(p, UART_LSR);
124 		if (!(lsr & UART_LSR_DR))
125 			return;
126 	}
127 
128 	(void)p->serial_in(p, UART_RX);
129 }
130 
131 static void dw8250_check_lcr(struct uart_port *p, int offset, int value)
132 {
133 	struct dw8250_data *d = to_dw8250_data(p->private_data);
134 	void __iomem *addr = p->membase + (offset << p->regshift);
135 	int tries = 1000;
136 
137 	if (offset != UART_LCR || d->uart_16550_compatible)
138 		return;
139 
140 	/* Make sure LCR write wasn't ignored */
141 	while (tries--) {
142 		unsigned int lcr = p->serial_in(p, offset);
143 
144 		if ((value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR))
145 			return;
146 
147 		dw8250_force_idle(p);
148 
149 #ifdef CONFIG_64BIT
150 		if (p->type == PORT_OCTEON)
151 			__raw_writeq(value & 0xff, addr);
152 		else
153 #endif
154 		if (p->iotype == UPIO_MEM32)
155 			writel(value, addr);
156 		else if (p->iotype == UPIO_MEM32BE)
157 			iowrite32be(value, addr);
158 		else
159 			writeb(value, addr);
160 	}
161 	/*
162 	 * FIXME: this deadlocks if port->lock is already held
163 	 * dev_err(p->dev, "Couldn't set LCR to %d\n", value);
164 	 */
165 }
166 
167 /* Returns once the transmitter is empty or we run out of retries */
168 static void dw8250_tx_wait_empty(struct uart_port *p)
169 {
170 	struct uart_8250_port *up = up_to_u8250p(p);
171 	unsigned int tries = 20000;
172 	unsigned int delay_threshold = tries - 1000;
173 	unsigned int lsr;
174 
175 	while (tries--) {
176 		lsr = readb (p->membase + (UART_LSR << p->regshift));
177 		up->lsr_saved_flags |= lsr & up->lsr_save_mask;
178 
179 		if (lsr & UART_LSR_TEMT)
180 			break;
181 
182 		/* The device is first given a chance to empty without delay,
183 		 * to avoid slowdowns at high bitrates. If after 1000 tries
184 		 * the buffer has still not emptied, allow more time for low-
185 		 * speed links. */
186 		if (tries < delay_threshold)
187 			udelay (1);
188 	}
189 }
190 
191 static void dw8250_serial_out(struct uart_port *p, int offset, int value)
192 {
193 	writeb(value, p->membase + (offset << p->regshift));
194 	dw8250_check_lcr(p, offset, value);
195 }
196 
197 static void dw8250_serial_out38x(struct uart_port *p, int offset, int value)
198 {
199 	/* Allow the TX to drain before we reconfigure */
200 	if (offset == UART_LCR)
201 		dw8250_tx_wait_empty(p);
202 
203 	dw8250_serial_out(p, offset, value);
204 }
205 
206 static unsigned int dw8250_serial_in(struct uart_port *p, int offset)
207 {
208 	unsigned int value = readb(p->membase + (offset << p->regshift));
209 
210 	return dw8250_modify_msr(p, offset, value);
211 }
212 
213 #ifdef CONFIG_64BIT
214 static unsigned int dw8250_serial_inq(struct uart_port *p, int offset)
215 {
216 	u8 value = __raw_readq(p->membase + (offset << p->regshift));
217 
218 	return dw8250_modify_msr(p, offset, value);
219 }
220 
221 static void dw8250_serial_outq(struct uart_port *p, int offset, int value)
222 {
223 	value &= 0xff;
224 	__raw_writeq(value, p->membase + (offset << p->regshift));
225 	/* Read back to ensure register write ordering. */
226 	__raw_readq(p->membase + (UART_LCR << p->regshift));
227 
228 	dw8250_check_lcr(p, offset, value);
229 }
230 #endif /* CONFIG_64BIT */
231 
232 static void dw8250_serial_out32(struct uart_port *p, int offset, int value)
233 {
234 	writel(value, p->membase + (offset << p->regshift));
235 	dw8250_check_lcr(p, offset, value);
236 }
237 
238 static unsigned int dw8250_serial_in32(struct uart_port *p, int offset)
239 {
240 	unsigned int value = readl(p->membase + (offset << p->regshift));
241 
242 	return dw8250_modify_msr(p, offset, value);
243 }
244 
245 static void dw8250_serial_out32be(struct uart_port *p, int offset, int value)
246 {
247 	iowrite32be(value, p->membase + (offset << p->regshift));
248 	dw8250_check_lcr(p, offset, value);
249 }
250 
251 static unsigned int dw8250_serial_in32be(struct uart_port *p, int offset)
252 {
253        unsigned int value = ioread32be(p->membase + (offset << p->regshift));
254 
255        return dw8250_modify_msr(p, offset, value);
256 }
257 
258 
259 static int dw8250_handle_irq(struct uart_port *p)
260 {
261 	struct uart_8250_port *up = up_to_u8250p(p);
262 	struct dw8250_data *d = to_dw8250_data(p->private_data);
263 	unsigned int iir = p->serial_in(p, UART_IIR);
264 	bool rx_timeout = (iir & 0x3f) == UART_IIR_RX_TIMEOUT;
265 	unsigned int quirks = d->pdata->quirks;
266 	unsigned int status;
267 	unsigned long flags;
268 
269 	/*
270 	 * There are ways to get Designware-based UARTs into a state where
271 	 * they are asserting UART_IIR_RX_TIMEOUT but there is no actual
272 	 * data available.  If we see such a case then we'll do a bogus
273 	 * read.  If we don't do this then the "RX TIMEOUT" interrupt will
274 	 * fire forever.
275 	 *
276 	 * This problem has only been observed so far when not in DMA mode
277 	 * so we limit the workaround only to non-DMA mode.
278 	 */
279 	if (!up->dma && rx_timeout) {
280 		uart_port_lock_irqsave(p, &flags);
281 		status = serial_lsr_in(up);
282 
283 		if (!(status & (UART_LSR_DR | UART_LSR_BI)))
284 			(void) p->serial_in(p, UART_RX);
285 
286 		uart_port_unlock_irqrestore(p, flags);
287 	}
288 
289 	/* Manually stop the Rx DMA transfer when acting as flow controller */
290 	if (quirks & DW_UART_QUIRK_IS_DMA_FC && up->dma && up->dma->rx_running && rx_timeout) {
291 		uart_port_lock_irqsave(p, &flags);
292 		status = serial_lsr_in(up);
293 		uart_port_unlock_irqrestore(p, flags);
294 
295 		if (status & (UART_LSR_DR | UART_LSR_BI)) {
296 			dw8250_writel_ext(p, RZN1_UART_RDMACR, 0);
297 			dw8250_writel_ext(p, DW_UART_DMASA, 1);
298 		}
299 	}
300 
301 	if (serial8250_handle_irq(p, iir))
302 		return 1;
303 
304 	if ((iir & UART_IIR_BUSY) == UART_IIR_BUSY) {
305 		/* Clear the USR */
306 		(void)p->serial_in(p, d->pdata->usr_reg);
307 
308 		return 1;
309 	}
310 
311 	return 0;
312 }
313 
314 static void dw8250_clk_work_cb(struct work_struct *work)
315 {
316 	struct dw8250_data *d = work_to_dw8250_data(work);
317 	struct uart_8250_port *up;
318 	unsigned long rate;
319 
320 	rate = clk_get_rate(d->clk);
321 	if (rate <= 0)
322 		return;
323 
324 	up = serial8250_get_port(d->data.line);
325 
326 	serial8250_update_uartclk(&up->port, rate);
327 }
328 
329 static int dw8250_clk_notifier_cb(struct notifier_block *nb,
330 				  unsigned long event, void *data)
331 {
332 	struct dw8250_data *d = clk_to_dw8250_data(nb);
333 
334 	/*
335 	 * We have no choice but to defer the uartclk update due to two
336 	 * deadlocks. First one is caused by a recursive mutex lock which
337 	 * happens when clk_set_rate() is called from dw8250_set_termios().
338 	 * Second deadlock is more tricky and is caused by an inverted order of
339 	 * the clk and tty-port mutexes lock. It happens if clock rate change
340 	 * is requested asynchronously while set_termios() is executed between
341 	 * tty-port mutex lock and clk_set_rate() function invocation and
342 	 * vise-versa. Anyway if we didn't have the reference clock alteration
343 	 * in the dw8250_set_termios() method we wouldn't have needed this
344 	 * deferred event handling complication.
345 	 */
346 	if (event == POST_RATE_CHANGE) {
347 		queue_work(system_unbound_wq, &d->clk_work);
348 		return NOTIFY_OK;
349 	}
350 
351 	return NOTIFY_DONE;
352 }
353 
354 static void
355 dw8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old)
356 {
357 	if (!state)
358 		pm_runtime_get_sync(port->dev);
359 
360 	serial8250_do_pm(port, state, old);
361 
362 	if (state)
363 		pm_runtime_put_sync_suspend(port->dev);
364 }
365 
366 static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios,
367 			       const struct ktermios *old)
368 {
369 	unsigned long newrate = tty_termios_baud_rate(termios) * 16;
370 	struct dw8250_data *d = to_dw8250_data(p->private_data);
371 	long rate;
372 	int ret;
373 
374 	clk_disable_unprepare(d->clk);
375 	rate = clk_round_rate(d->clk, newrate);
376 	if (rate > 0) {
377 		/*
378 		 * Note that any clock-notifer worker will block in
379 		 * serial8250_update_uartclk() until we are done.
380 		 */
381 		ret = clk_set_rate(d->clk, newrate);
382 		if (!ret)
383 			p->uartclk = rate;
384 	}
385 	clk_prepare_enable(d->clk);
386 
387 	dw8250_do_set_termios(p, termios, old);
388 }
389 
390 static void dw8250_set_ldisc(struct uart_port *p, struct ktermios *termios)
391 {
392 	struct uart_8250_port *up = up_to_u8250p(p);
393 	unsigned int mcr = p->serial_in(p, UART_MCR);
394 
395 	if (up->capabilities & UART_CAP_IRDA) {
396 		if (termios->c_line == N_IRDA)
397 			mcr |= DW_UART_MCR_SIRE;
398 		else
399 			mcr &= ~DW_UART_MCR_SIRE;
400 
401 		p->serial_out(p, UART_MCR, mcr);
402 	}
403 	serial8250_do_set_ldisc(p, termios);
404 }
405 
406 /*
407  * dw8250_fallback_dma_filter will prevent the UART from getting just any free
408  * channel on platforms that have DMA engines, but don't have any channels
409  * assigned to the UART.
410  *
411  * REVISIT: This is a work around for limitation in the DMA Engine API. Once the
412  * core problem is fixed, this function is no longer needed.
413  */
414 static bool dw8250_fallback_dma_filter(struct dma_chan *chan, void *param)
415 {
416 	return false;
417 }
418 
419 static bool dw8250_idma_filter(struct dma_chan *chan, void *param)
420 {
421 	return param == chan->device->dev;
422 }
423 
424 static u32 dw8250_rzn1_get_dmacr_burst(int max_burst)
425 {
426 	if (max_burst >= 8)
427 		return RZN1_UART_xDMACR_8_WORD_BURST;
428 	else if (max_burst >= 4)
429 		return RZN1_UART_xDMACR_4_WORD_BURST;
430 	else
431 		return RZN1_UART_xDMACR_1_WORD_BURST;
432 }
433 
434 static void dw8250_prepare_tx_dma(struct uart_8250_port *p)
435 {
436 	struct uart_port *up = &p->port;
437 	struct uart_8250_dma *dma = p->dma;
438 	u32 val;
439 
440 	dw8250_writel_ext(up, RZN1_UART_TDMACR, 0);
441 	val = dw8250_rzn1_get_dmacr_burst(dma->txconf.dst_maxburst) |
442 	      RZN1_UART_xDMACR_BLK_SZ(dma->tx_size) |
443 	      RZN1_UART_xDMACR_DMA_EN;
444 	dw8250_writel_ext(up, RZN1_UART_TDMACR, val);
445 }
446 
447 static void dw8250_prepare_rx_dma(struct uart_8250_port *p)
448 {
449 	struct uart_port *up = &p->port;
450 	struct uart_8250_dma *dma = p->dma;
451 	u32 val;
452 
453 	dw8250_writel_ext(up, RZN1_UART_RDMACR, 0);
454 	val = dw8250_rzn1_get_dmacr_burst(dma->rxconf.src_maxburst) |
455 	      RZN1_UART_xDMACR_BLK_SZ(dma->rx_size) |
456 	      RZN1_UART_xDMACR_DMA_EN;
457 	dw8250_writel_ext(up, RZN1_UART_RDMACR, val);
458 }
459 
460 static void dw8250_quirks(struct uart_port *p, struct dw8250_data *data)
461 {
462 	unsigned int quirks = data->pdata ? data->pdata->quirks : 0;
463 	u32 cpr_value = data->pdata ? data->pdata->cpr_value : 0;
464 
465 	if (quirks & DW_UART_QUIRK_CPR_VALUE)
466 		data->data.cpr_value = cpr_value;
467 
468 #ifdef CONFIG_64BIT
469 	if (quirks & DW_UART_QUIRK_OCTEON) {
470 		p->serial_in = dw8250_serial_inq;
471 		p->serial_out = dw8250_serial_outq;
472 		p->flags = UPF_SKIP_TEST | UPF_SHARE_IRQ | UPF_FIXED_TYPE;
473 		p->type = PORT_OCTEON;
474 		data->skip_autocfg = true;
475 	}
476 #endif
477 
478 	if (quirks & DW_UART_QUIRK_ARMADA_38X)
479 		p->serial_out = dw8250_serial_out38x;
480 	if (quirks & DW_UART_QUIRK_SKIP_SET_RATE)
481 		p->set_termios = dw8250_do_set_termios;
482 	if (quirks & DW_UART_QUIRK_IS_DMA_FC) {
483 		data->data.dma.txconf.device_fc = 1;
484 		data->data.dma.rxconf.device_fc = 1;
485 		data->data.dma.prepare_tx_dma = dw8250_prepare_tx_dma;
486 		data->data.dma.prepare_rx_dma = dw8250_prepare_rx_dma;
487 	}
488 	if (quirks & DW_UART_QUIRK_APMC0D08) {
489 		p->iotype = UPIO_MEM32;
490 		p->regshift = 2;
491 		p->serial_in = dw8250_serial_in32;
492 		data->uart_16550_compatible = true;
493 	}
494 
495 	/* Platforms with iDMA 64-bit */
496 	if (platform_get_resource_byname(to_platform_device(p->dev),
497 					 IORESOURCE_MEM, "lpss_priv")) {
498 		data->data.dma.rx_param = p->dev->parent;
499 		data->data.dma.tx_param = p->dev->parent;
500 		data->data.dma.fn = dw8250_idma_filter;
501 	}
502 }
503 
504 static void dw8250_reset_control_assert(void *data)
505 {
506 	reset_control_assert(data);
507 }
508 
509 static int dw8250_probe(struct platform_device *pdev)
510 {
511 	struct uart_8250_port uart = {}, *up = &uart;
512 	struct uart_port *p = &up->port;
513 	struct device *dev = &pdev->dev;
514 	struct dw8250_data *data;
515 	struct resource *regs;
516 	int err;
517 
518 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
519 	if (!regs)
520 		return dev_err_probe(dev, -EINVAL, "no registers defined\n");
521 
522 	spin_lock_init(&p->lock);
523 	p->handle_irq	= dw8250_handle_irq;
524 	p->pm		= dw8250_do_pm;
525 	p->type		= PORT_8250;
526 	p->flags	= UPF_FIXED_PORT;
527 	p->dev		= dev;
528 	p->set_ldisc	= dw8250_set_ldisc;
529 	p->set_termios	= dw8250_set_termios;
530 
531 	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
532 	if (!data)
533 		return -ENOMEM;
534 
535 	data->data.dma.fn = dw8250_fallback_dma_filter;
536 	data->pdata = device_get_match_data(p->dev);
537 	p->private_data = &data->data;
538 
539 	data->uart_16550_compatible = device_property_read_bool(dev,
540 						"snps,uart-16550-compatible");
541 
542 	p->mapbase = regs->start;
543 	p->mapsize = resource_size(regs);
544 
545 	p->membase = devm_ioremap(dev, p->mapbase, p->mapsize);
546 	if (!p->membase)
547 		return -ENOMEM;
548 
549 	err = uart_read_port_properties(p);
550 	/* no interrupt -> fall back to polling */
551 	if (err == -ENXIO)
552 		err = 0;
553 	if (err)
554 		return err;
555 
556 	switch (p->iotype) {
557 	case UPIO_MEM:
558 		p->serial_in = dw8250_serial_in;
559 		p->serial_out = dw8250_serial_out;
560 		break;
561 	case UPIO_MEM32:
562 		p->serial_in = dw8250_serial_in32;
563 		p->serial_out = dw8250_serial_out32;
564 		break;
565 	case UPIO_MEM32BE:
566 		p->serial_in = dw8250_serial_in32be;
567 		p->serial_out = dw8250_serial_out32be;
568 		break;
569 	default:
570 		return -ENODEV;
571 	}
572 
573 	if (device_property_read_bool(dev, "dcd-override")) {
574 		/* Always report DCD as active */
575 		data->msr_mask_on |= UART_MSR_DCD;
576 		data->msr_mask_off |= UART_MSR_DDCD;
577 	}
578 
579 	if (device_property_read_bool(dev, "dsr-override")) {
580 		/* Always report DSR as active */
581 		data->msr_mask_on |= UART_MSR_DSR;
582 		data->msr_mask_off |= UART_MSR_DDSR;
583 	}
584 
585 	if (device_property_read_bool(dev, "cts-override")) {
586 		/* Always report CTS as active */
587 		data->msr_mask_on |= UART_MSR_CTS;
588 		data->msr_mask_off |= UART_MSR_DCTS;
589 	}
590 
591 	if (device_property_read_bool(dev, "ri-override")) {
592 		/* Always report Ring indicator as inactive */
593 		data->msr_mask_off |= UART_MSR_RI;
594 		data->msr_mask_off |= UART_MSR_TERI;
595 	}
596 
597 	/* If there is separate baudclk, get the rate from it. */
598 	data->clk = devm_clk_get_optional_enabled(dev, "baudclk");
599 	if (data->clk == NULL)
600 		data->clk = devm_clk_get_optional_enabled(dev, NULL);
601 	if (IS_ERR(data->clk))
602 		return dev_err_probe(dev, PTR_ERR(data->clk),
603 				     "failed to get baudclk\n");
604 
605 	INIT_WORK(&data->clk_work, dw8250_clk_work_cb);
606 	data->clk_notifier.notifier_call = dw8250_clk_notifier_cb;
607 
608 	if (data->clk)
609 		p->uartclk = clk_get_rate(data->clk);
610 
611 	/* If no clock rate is defined, fail. */
612 	if (!p->uartclk)
613 		return dev_err_probe(dev, -EINVAL, "clock rate not defined\n");
614 
615 	data->pclk = devm_clk_get_optional_enabled(dev, "apb_pclk");
616 	if (IS_ERR(data->pclk))
617 		return PTR_ERR(data->pclk);
618 
619 	data->rst = devm_reset_control_array_get_optional_exclusive(dev);
620 	if (IS_ERR(data->rst))
621 		return PTR_ERR(data->rst);
622 
623 	reset_control_deassert(data->rst);
624 
625 	err = devm_add_action_or_reset(dev, dw8250_reset_control_assert, data->rst);
626 	if (err)
627 		return err;
628 
629 	dw8250_quirks(p, data);
630 
631 	/* If the Busy Functionality is not implemented, don't handle it */
632 	if (data->uart_16550_compatible)
633 		p->handle_irq = NULL;
634 
635 	if (!data->skip_autocfg)
636 		dw8250_setup_port(p);
637 
638 	/* If we have a valid fifosize, try hooking up DMA */
639 	if (p->fifosize) {
640 		data->data.dma.rxconf.src_maxburst = p->fifosize / 4;
641 		data->data.dma.txconf.dst_maxburst = p->fifosize / 4;
642 		up->dma = &data->data.dma;
643 	}
644 
645 	data->data.line = serial8250_register_8250_port(up);
646 	if (data->data.line < 0)
647 		return data->data.line;
648 
649 	/*
650 	 * Some platforms may provide a reference clock shared between several
651 	 * devices. In this case any clock state change must be known to the
652 	 * UART port at least post factum.
653 	 */
654 	if (data->clk) {
655 		err = clk_notifier_register(data->clk, &data->clk_notifier);
656 		if (err)
657 			return dev_err_probe(dev, err, "Failed to set the clock notifier\n");
658 		queue_work(system_unbound_wq, &data->clk_work);
659 	}
660 
661 	platform_set_drvdata(pdev, data);
662 
663 	pm_runtime_set_active(dev);
664 	pm_runtime_enable(dev);
665 
666 	return 0;
667 }
668 
669 static void dw8250_remove(struct platform_device *pdev)
670 {
671 	struct dw8250_data *data = platform_get_drvdata(pdev);
672 	struct device *dev = &pdev->dev;
673 
674 	pm_runtime_get_sync(dev);
675 
676 	if (data->clk) {
677 		clk_notifier_unregister(data->clk, &data->clk_notifier);
678 
679 		flush_work(&data->clk_work);
680 	}
681 
682 	serial8250_unregister_port(data->data.line);
683 
684 	pm_runtime_disable(dev);
685 	pm_runtime_put_noidle(dev);
686 }
687 
688 static int dw8250_suspend(struct device *dev)
689 {
690 	struct dw8250_data *data = dev_get_drvdata(dev);
691 
692 	serial8250_suspend_port(data->data.line);
693 
694 	return 0;
695 }
696 
697 static int dw8250_resume(struct device *dev)
698 {
699 	struct dw8250_data *data = dev_get_drvdata(dev);
700 
701 	serial8250_resume_port(data->data.line);
702 
703 	return 0;
704 }
705 
706 static int dw8250_runtime_suspend(struct device *dev)
707 {
708 	struct dw8250_data *data = dev_get_drvdata(dev);
709 
710 	clk_disable_unprepare(data->clk);
711 
712 	clk_disable_unprepare(data->pclk);
713 
714 	return 0;
715 }
716 
717 static int dw8250_runtime_resume(struct device *dev)
718 {
719 	struct dw8250_data *data = dev_get_drvdata(dev);
720 
721 	clk_prepare_enable(data->pclk);
722 
723 	clk_prepare_enable(data->clk);
724 
725 	return 0;
726 }
727 
728 static const struct dev_pm_ops dw8250_pm_ops = {
729 	SYSTEM_SLEEP_PM_OPS(dw8250_suspend, dw8250_resume)
730 	RUNTIME_PM_OPS(dw8250_runtime_suspend, dw8250_runtime_resume, NULL)
731 };
732 
733 static const struct dw8250_platform_data dw8250_dw_apb = {
734 	.usr_reg = DW_UART_USR,
735 };
736 
737 static const struct dw8250_platform_data dw8250_octeon_3860_data = {
738 	.usr_reg = OCTEON_UART_USR,
739 	.quirks = DW_UART_QUIRK_OCTEON,
740 };
741 
742 static const struct dw8250_platform_data dw8250_armada_38x_data = {
743 	.usr_reg = DW_UART_USR,
744 	.quirks = DW_UART_QUIRK_ARMADA_38X,
745 };
746 
747 static const struct dw8250_platform_data dw8250_renesas_rzn1_data = {
748 	.usr_reg = DW_UART_USR,
749 	.cpr_value = 0x00012f32,
750 	.quirks = DW_UART_QUIRK_CPR_VALUE | DW_UART_QUIRK_IS_DMA_FC,
751 };
752 
753 static const struct dw8250_platform_data dw8250_starfive_jh7100_data = {
754 	.usr_reg = DW_UART_USR,
755 	.quirks = DW_UART_QUIRK_SKIP_SET_RATE,
756 };
757 
758 static const struct of_device_id dw8250_of_match[] = {
759 	{ .compatible = "snps,dw-apb-uart", .data = &dw8250_dw_apb },
760 	{ .compatible = "cavium,octeon-3860-uart", .data = &dw8250_octeon_3860_data },
761 	{ .compatible = "marvell,armada-38x-uart", .data = &dw8250_armada_38x_data },
762 	{ .compatible = "renesas,rzn1-uart", .data = &dw8250_renesas_rzn1_data },
763 	{ .compatible = "starfive,jh7100-uart", .data = &dw8250_starfive_jh7100_data },
764 	{ /* Sentinel */ }
765 };
766 MODULE_DEVICE_TABLE(of, dw8250_of_match);
767 
768 static const struct dw8250_platform_data dw8250_apmc0d08 = {
769 	.usr_reg = DW_UART_USR,
770 	.quirks = DW_UART_QUIRK_APMC0D08,
771 };
772 
773 static const struct acpi_device_id dw8250_acpi_match[] = {
774 	{ "80860F0A", (kernel_ulong_t)&dw8250_dw_apb },
775 	{ "8086228A", (kernel_ulong_t)&dw8250_dw_apb },
776 	{ "AMD0020", (kernel_ulong_t)&dw8250_dw_apb },
777 	{ "AMDI0020", (kernel_ulong_t)&dw8250_dw_apb },
778 	{ "AMDI0022", (kernel_ulong_t)&dw8250_dw_apb },
779 	{ "APMC0D08", (kernel_ulong_t)&dw8250_apmc0d08 },
780 	{ "BRCM2032", (kernel_ulong_t)&dw8250_dw_apb },
781 	{ "HISI0031", (kernel_ulong_t)&dw8250_dw_apb },
782 	{ "INT33C4", (kernel_ulong_t)&dw8250_dw_apb },
783 	{ "INT33C5", (kernel_ulong_t)&dw8250_dw_apb },
784 	{ "INT3434", (kernel_ulong_t)&dw8250_dw_apb },
785 	{ "INT3435", (kernel_ulong_t)&dw8250_dw_apb },
786 	{ "INTC10EE", (kernel_ulong_t)&dw8250_dw_apb },
787 	{ },
788 };
789 MODULE_DEVICE_TABLE(acpi, dw8250_acpi_match);
790 
791 static struct platform_driver dw8250_platform_driver = {
792 	.driver = {
793 		.name		= "dw-apb-uart",
794 		.pm		= pm_ptr(&dw8250_pm_ops),
795 		.of_match_table	= dw8250_of_match,
796 		.acpi_match_table = dw8250_acpi_match,
797 	},
798 	.probe			= dw8250_probe,
799 	.remove_new		= dw8250_remove,
800 };
801 
802 module_platform_driver(dw8250_platform_driver);
803 
804 MODULE_AUTHOR("Jamie Iles");
805 MODULE_LICENSE("GPL");
806 MODULE_DESCRIPTION("Synopsys DesignWare 8250 serial port driver");
807 MODULE_ALIAS("platform:dw-apb-uart");
808