xref: /linux/drivers/tty/serial/8250/8250_mtk.c (revision 3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Mediatek 8250 driver.
4  *
5  * Copyright (c) 2014 MundoReader S.L.
6  * Author: Matthias Brugger <matthias.bgg@gmail.com>
7  */
8 #include <linux/clk.h>
9 #include <linux/io.h>
10 #include <linux/module.h>
11 #include <linux/of.h>
12 #include <linux/of_irq.h>
13 #include <linux/of_platform.h>
14 #include <linux/pinctrl/consumer.h>
15 #include <linux/platform_device.h>
16 #include <linux/pm_runtime.h>
17 #include <linux/serial_8250.h>
18 #include <linux/serial_reg.h>
19 #include <linux/console.h>
20 #include <linux/dma-mapping.h>
21 #include <linux/tty.h>
22 #include <linux/tty_flip.h>
23 #include <linux/units.h>
24 
25 #include "8250.h"
26 
27 #define MTK_UART_HIGHS		0x09	/* Highspeed register */
28 #define MTK_UART_SAMPLE_COUNT	0x0a	/* Sample count register */
29 #define MTK_UART_SAMPLE_POINT	0x0b	/* Sample point register */
30 #define MTK_UART_RATE_FIX	0x0d	/* UART Rate Fix Register */
31 #define MTK_UART_ESCAPE_DAT	0x10	/* Escape Character register */
32 #define MTK_UART_ESCAPE_EN	0x11	/* Escape Enable register */
33 #define MTK_UART_DMA_EN		0x13	/* DMA Enable register */
34 #define MTK_UART_RXTRI_AD	0x14	/* RX Trigger address */
35 #define MTK_UART_FRACDIV_L	0x15	/* Fractional divider LSB address */
36 #define MTK_UART_FRACDIV_M	0x16	/* Fractional divider MSB address */
37 #define MTK_UART_DEBUG0	0x18
38 #define MTK_UART_IER_XOFFI	0x20	/* Enable XOFF character interrupt */
39 #define MTK_UART_IER_RTSI	0x40	/* Enable RTS Modem status interrupt */
40 #define MTK_UART_IER_CTSI	0x80	/* Enable CTS Modem status interrupt */
41 
42 #define MTK_UART_EFR		38	/* I/O: Extended Features Register */
43 #define MTK_UART_EFR_EN		0x10	/* Enable enhancement feature */
44 #define MTK_UART_EFR_RTS	0x40	/* Enable hardware rx flow control */
45 #define MTK_UART_EFR_CTS	0x80	/* Enable hardware tx flow control */
46 #define MTK_UART_EFR_NO_SW_FC	0x0	/* no sw flow control */
47 #define MTK_UART_EFR_XON1_XOFF1	0xa	/* XON1/XOFF1 as sw flow control */
48 #define MTK_UART_EFR_XON2_XOFF2	0x5	/* XON2/XOFF2 as sw flow control */
49 #define MTK_UART_EFR_SW_FC_MASK	0xf	/* Enable CTS Modem status interrupt */
50 #define MTK_UART_EFR_HW_FC	(MTK_UART_EFR_RTS | MTK_UART_EFR_CTS)
51 #define MTK_UART_DMA_EN_TX	0x2
52 #define MTK_UART_DMA_EN_RX	0x5
53 
54 #define MTK_UART_ESCAPE_CHAR	0x77	/* Escape char added under sw fc */
55 #define MTK_UART_RX_SIZE	0x8000
56 #define MTK_UART_TX_TRIGGER	1
57 #define MTK_UART_RX_TRIGGER	MTK_UART_RX_SIZE
58 
59 #define MTK_UART_XON1		40	/* I/O: Xon character 1 */
60 #define MTK_UART_XOFF1		42	/* I/O: Xoff character 1 */
61 
62 #ifdef CONFIG_SERIAL_8250_DMA
63 enum dma_rx_status {
64 	DMA_RX_START = 0,
65 	DMA_RX_RUNNING = 1,
66 	DMA_RX_SHUTDOWN = 2,
67 };
68 #endif
69 
70 struct mtk8250_data {
71 	int			line;
72 	unsigned int		rx_pos;
73 	unsigned int		clk_count;
74 	struct clk		*uart_clk;
75 	struct clk		*bus_clk;
76 	struct uart_8250_dma	*dma;
77 #ifdef CONFIG_SERIAL_8250_DMA
78 	enum dma_rx_status	rx_status;
79 #endif
80 	int			rx_wakeup_irq;
81 };
82 
83 /* flow control mode */
84 enum {
85 	MTK_UART_FC_NONE,
86 	MTK_UART_FC_SW,
87 	MTK_UART_FC_HW,
88 };
89 
90 #ifdef CONFIG_SERIAL_8250_DMA
91 static void mtk8250_rx_dma(struct uart_8250_port *up);
92 
93 static void mtk8250_dma_rx_complete(void *param)
94 {
95 	struct uart_8250_port *up = param;
96 	struct uart_8250_dma *dma = up->dma;
97 	struct mtk8250_data *data = up->port.private_data;
98 	struct tty_port *tty_port = &up->port.state->port;
99 	struct dma_tx_state state;
100 	int copied, total, cnt;
101 	unsigned char *ptr;
102 	unsigned long flags;
103 
104 	if (data->rx_status == DMA_RX_SHUTDOWN)
105 		return;
106 
107 	uart_port_lock_irqsave(&up->port, &flags);
108 
109 	dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state);
110 	total = dma->rx_size - state.residue;
111 	cnt = total;
112 
113 	if ((data->rx_pos + cnt) > dma->rx_size)
114 		cnt = dma->rx_size - data->rx_pos;
115 
116 	ptr = (unsigned char *)(data->rx_pos + dma->rx_buf);
117 	copied = tty_insert_flip_string(tty_port, ptr, cnt);
118 	data->rx_pos += cnt;
119 
120 	if (total > cnt) {
121 		ptr = (unsigned char *)(dma->rx_buf);
122 		cnt = total - cnt;
123 		copied += tty_insert_flip_string(tty_port, ptr, cnt);
124 		data->rx_pos = cnt;
125 	}
126 
127 	up->port.icount.rx += copied;
128 
129 	tty_flip_buffer_push(tty_port);
130 
131 	mtk8250_rx_dma(up);
132 
133 	uart_port_unlock_irqrestore(&up->port, flags);
134 }
135 
136 static void mtk8250_rx_dma(struct uart_8250_port *up)
137 {
138 	struct uart_8250_dma *dma = up->dma;
139 	struct dma_async_tx_descriptor	*desc;
140 
141 	desc = dmaengine_prep_slave_single(dma->rxchan, dma->rx_addr,
142 					   dma->rx_size, DMA_DEV_TO_MEM,
143 					   DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
144 	if (!desc) {
145 		pr_err("failed to prepare rx slave single\n");
146 		return;
147 	}
148 
149 	desc->callback = mtk8250_dma_rx_complete;
150 	desc->callback_param = up;
151 
152 	dma->rx_cookie = dmaengine_submit(desc);
153 
154 	dma_async_issue_pending(dma->rxchan);
155 }
156 
157 static void mtk8250_dma_enable(struct uart_8250_port *up)
158 {
159 	struct uart_8250_dma *dma = up->dma;
160 	struct mtk8250_data *data = up->port.private_data;
161 	int lcr = serial_in(up, UART_LCR);
162 
163 	if (data->rx_status != DMA_RX_START)
164 		return;
165 
166 	dma->rxconf.src_port_window_size	= dma->rx_size;
167 	dma->rxconf.src_addr				= dma->rx_addr;
168 
169 	dma->txconf.dst_port_window_size	= UART_XMIT_SIZE;
170 	dma->txconf.dst_addr				= dma->tx_addr;
171 
172 	serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR |
173 		UART_FCR_CLEAR_XMIT);
174 	serial_out(up, MTK_UART_DMA_EN,
175 		   MTK_UART_DMA_EN_RX | MTK_UART_DMA_EN_TX);
176 
177 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
178 	serial_out(up, MTK_UART_EFR, UART_EFR_ECB);
179 	serial_out(up, UART_LCR, lcr);
180 
181 	if (dmaengine_slave_config(dma->rxchan, &dma->rxconf) != 0)
182 		pr_err("failed to configure rx dma channel\n");
183 	if (dmaengine_slave_config(dma->txchan, &dma->txconf) != 0)
184 		pr_err("failed to configure tx dma channel\n");
185 
186 	data->rx_status = DMA_RX_RUNNING;
187 	data->rx_pos = 0;
188 	mtk8250_rx_dma(up);
189 }
190 #endif
191 
192 static int mtk8250_startup(struct uart_port *port)
193 {
194 #ifdef CONFIG_SERIAL_8250_DMA
195 	struct uart_8250_port *up = up_to_u8250p(port);
196 	struct mtk8250_data *data = port->private_data;
197 
198 	/* disable DMA for console */
199 	if (uart_console(port))
200 		up->dma = NULL;
201 
202 	if (up->dma) {
203 		data->rx_status = DMA_RX_START;
204 		kfifo_reset(&port->state->port.xmit_fifo);
205 	}
206 #endif
207 	memset(&port->icount, 0, sizeof(port->icount));
208 
209 	return serial8250_do_startup(port);
210 }
211 
212 static void mtk8250_shutdown(struct uart_port *port)
213 {
214 	struct uart_8250_port *up = up_to_u8250p(port);
215 	struct mtk8250_data *data = port->private_data;
216 	int irq = data->rx_wakeup_irq;
217 
218 #ifdef CONFIG_SERIAL_8250_DMA
219 	if (up->dma)
220 		data->rx_status = DMA_RX_SHUTDOWN;
221 #endif
222 
223 	serial8250_do_shutdown(port);
224 
225 	if (irq >= 0)
226 		serial8250_do_set_mctrl(&up->port, TIOCM_RTS);
227 }
228 
229 static void mtk8250_disable_intrs(struct uart_8250_port *up, int mask)
230 {
231 	/* Port locked to synchronize UART_IER access against the console. */
232 	lockdep_assert_held_once(&up->port.lock);
233 
234 	serial_out(up, UART_IER, serial_in(up, UART_IER) & (~mask));
235 }
236 
237 static void mtk8250_enable_intrs(struct uart_8250_port *up, int mask)
238 {
239 	/* Port locked to synchronize UART_IER access against the console. */
240 	lockdep_assert_held_once(&up->port.lock);
241 
242 	serial_out(up, UART_IER, serial_in(up, UART_IER) | mask);
243 }
244 
245 static void mtk8250_set_flow_ctrl(struct uart_8250_port *up, int mode)
246 {
247 	struct uart_port *port = &up->port;
248 	int lcr = serial_in(up, UART_LCR);
249 
250 	/* Port locked to synchronize UART_IER access against the console. */
251 	lockdep_assert_held_once(&port->lock);
252 
253 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
254 	serial_out(up, MTK_UART_EFR, UART_EFR_ECB);
255 	serial_out(up, UART_LCR, lcr);
256 	lcr = serial_in(up, UART_LCR);
257 
258 	switch (mode) {
259 	case MTK_UART_FC_NONE:
260 		serial_out(up, MTK_UART_ESCAPE_DAT, MTK_UART_ESCAPE_CHAR);
261 		serial_out(up, MTK_UART_ESCAPE_EN, 0x00);
262 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
263 		serial_out(up, MTK_UART_EFR, serial_in(up, MTK_UART_EFR) &
264 			(~(MTK_UART_EFR_HW_FC | MTK_UART_EFR_SW_FC_MASK)));
265 		serial_out(up, UART_LCR, lcr);
266 		mtk8250_disable_intrs(up, MTK_UART_IER_XOFFI |
267 			MTK_UART_IER_RTSI | MTK_UART_IER_CTSI);
268 		break;
269 
270 	case MTK_UART_FC_HW:
271 		serial_out(up, MTK_UART_ESCAPE_DAT, MTK_UART_ESCAPE_CHAR);
272 		serial_out(up, MTK_UART_ESCAPE_EN, 0x00);
273 		serial_out(up, UART_MCR, UART_MCR_RTS);
274 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
275 
276 		/*enable hw flow control*/
277 		serial_out(up, MTK_UART_EFR, MTK_UART_EFR_HW_FC |
278 			(serial_in(up, MTK_UART_EFR) &
279 			(~(MTK_UART_EFR_HW_FC | MTK_UART_EFR_SW_FC_MASK))));
280 
281 		serial_out(up, UART_LCR, lcr);
282 		mtk8250_disable_intrs(up, MTK_UART_IER_XOFFI);
283 		mtk8250_enable_intrs(up, MTK_UART_IER_CTSI | MTK_UART_IER_RTSI);
284 		break;
285 
286 	case MTK_UART_FC_SW:	/*MTK software flow control */
287 		serial_out(up, MTK_UART_ESCAPE_DAT, MTK_UART_ESCAPE_CHAR);
288 		serial_out(up, MTK_UART_ESCAPE_EN, 0x01);
289 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
290 
291 		/*enable sw flow control */
292 		serial_out(up, MTK_UART_EFR, MTK_UART_EFR_XON1_XOFF1 |
293 			(serial_in(up, MTK_UART_EFR) &
294 			(~(MTK_UART_EFR_HW_FC | MTK_UART_EFR_SW_FC_MASK))));
295 
296 		serial_out(up, MTK_UART_XON1, START_CHAR(port->state->port.tty));
297 		serial_out(up, MTK_UART_XOFF1, STOP_CHAR(port->state->port.tty));
298 		serial_out(up, UART_LCR, lcr);
299 		mtk8250_disable_intrs(up, MTK_UART_IER_CTSI|MTK_UART_IER_RTSI);
300 		mtk8250_enable_intrs(up, MTK_UART_IER_XOFFI);
301 		break;
302 	default:
303 		break;
304 	}
305 }
306 
307 static void
308 mtk8250_set_termios(struct uart_port *port, struct ktermios *termios,
309 		    const struct ktermios *old)
310 {
311 	static const unsigned short fraction_L_mapping[] = {
312 		0, 1, 0x5, 0x15, 0x55, 0x57, 0x57, 0x77, 0x7F, 0xFF, 0xFF
313 	};
314 	static const unsigned short fraction_M_mapping[] = {
315 		0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 3
316 	};
317 	struct uart_8250_port *up = up_to_u8250p(port);
318 	unsigned int baud, quot, fraction;
319 	unsigned long flags;
320 	int mode;
321 
322 #ifdef CONFIG_SERIAL_8250_DMA
323 	if (up->dma) {
324 		if (uart_console(port)) {
325 			devm_kfree(up->port.dev, up->dma);
326 			up->dma = NULL;
327 		} else {
328 			mtk8250_dma_enable(up);
329 		}
330 	}
331 #endif
332 
333 	/*
334 	 * Store the requested baud rate before calling the generic 8250
335 	 * set_termios method. Standard 8250 port expects bauds to be
336 	 * no higher than (uartclk / 16) so the baud will be clamped if it
337 	 * gets out of that bound. Mediatek 8250 port supports speed
338 	 * higher than that, therefore we'll get original baud rate back
339 	 * after calling the generic set_termios method and recalculate
340 	 * the speed later in this method.
341 	 */
342 	baud = tty_termios_baud_rate(termios);
343 
344 	serial8250_do_set_termios(port, termios, NULL);
345 
346 	tty_termios_encode_baud_rate(termios, baud, baud);
347 
348 	/*
349 	 * Mediatek UARTs use an extra highspeed register (MTK_UART_HIGHS)
350 	 *
351 	 * We need to recalculate the quot register, as the calculation depends
352 	 * on the value in the highspeed register.
353 	 *
354 	 * Some baudrates are not supported by the chip, so we use the next
355 	 * lower rate supported and update termios c_flag.
356 	 *
357 	 * If highspeed register is set to 3, we need to specify sample count
358 	 * and sample point to increase accuracy. If not, we reset the
359 	 * registers to their default values.
360 	 */
361 	baud = uart_get_baud_rate(port, termios, old,
362 				  port->uartclk / 16 / UART_DIV_MAX,
363 				  port->uartclk);
364 
365 	if (baud < 115200) {
366 		serial_port_out(port, MTK_UART_HIGHS, 0x0);
367 		quot = uart_get_divisor(port, baud);
368 	} else {
369 		serial_port_out(port, MTK_UART_HIGHS, 0x3);
370 		quot = DIV_ROUND_UP(port->uartclk, 256 * baud);
371 	}
372 
373 	/*
374 	 * Ok, we're now changing the port state.  Do it with
375 	 * interrupts disabled.
376 	 */
377 	uart_port_lock_irqsave(port, &flags);
378 
379 	/*
380 	 * Update the per-port timeout.
381 	 */
382 	uart_update_timeout(port, termios->c_cflag, baud);
383 
384 	/* set DLAB we have cval saved in up->lcr from the call to the core */
385 	serial_port_out(port, UART_LCR, up->lcr | UART_LCR_DLAB);
386 	serial_dl_write(up, quot);
387 
388 	/* reset DLAB */
389 	serial_port_out(port, UART_LCR, up->lcr);
390 
391 	if (baud >= 115200) {
392 		unsigned int tmp;
393 
394 		tmp = (port->uartclk / (baud *  quot)) - 1;
395 		serial_port_out(port, MTK_UART_SAMPLE_COUNT, tmp);
396 		serial_port_out(port, MTK_UART_SAMPLE_POINT,
397 					(tmp >> 1) - 1);
398 
399 		/*count fraction to set fractoin register */
400 		fraction = ((port->uartclk  * 100) / baud / quot) % 100;
401 		fraction = DIV_ROUND_CLOSEST(fraction, 10);
402 		serial_port_out(port, MTK_UART_FRACDIV_L,
403 						fraction_L_mapping[fraction]);
404 		serial_port_out(port, MTK_UART_FRACDIV_M,
405 						fraction_M_mapping[fraction]);
406 	} else {
407 		serial_port_out(port, MTK_UART_SAMPLE_COUNT, 0x00);
408 		serial_port_out(port, MTK_UART_SAMPLE_POINT, 0xff);
409 		serial_port_out(port, MTK_UART_FRACDIV_L, 0x00);
410 		serial_port_out(port, MTK_UART_FRACDIV_M, 0x00);
411 	}
412 
413 	if ((termios->c_cflag & CRTSCTS) && (!(termios->c_iflag & CRTSCTS)))
414 		mode = MTK_UART_FC_HW;
415 	else if (termios->c_iflag & CRTSCTS)
416 		mode = MTK_UART_FC_SW;
417 	else
418 		mode = MTK_UART_FC_NONE;
419 
420 	mtk8250_set_flow_ctrl(up, mode);
421 
422 	if (uart_console(port))
423 		up->port.cons->cflag = termios->c_cflag;
424 
425 	uart_port_unlock_irqrestore(port, flags);
426 	/* Don't rewrite B0 */
427 	if (tty_termios_baud_rate(termios))
428 		tty_termios_encode_baud_rate(termios, baud, baud);
429 }
430 
431 static int __maybe_unused mtk8250_runtime_suspend(struct device *dev)
432 {
433 	struct mtk8250_data *data = dev_get_drvdata(dev);
434 	struct uart_8250_port *up = serial8250_get_port(data->line);
435 
436 	/* wait until UART in idle status */
437 	while
438 		(serial_in(up, MTK_UART_DEBUG0));
439 
440 	clk_disable_unprepare(data->uart_clk);
441 	clk_disable_unprepare(data->bus_clk);
442 
443 	return 0;
444 }
445 
446 static int __maybe_unused mtk8250_runtime_resume(struct device *dev)
447 {
448 	struct mtk8250_data *data = dev_get_drvdata(dev);
449 
450 	clk_prepare_enable(data->bus_clk);
451 	clk_prepare_enable(data->uart_clk);
452 
453 	return 0;
454 }
455 
456 static void
457 mtk8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old)
458 {
459 	if (!state)
460 		pm_runtime_get_sync(port->dev);
461 
462 	serial8250_do_pm(port, state, old);
463 
464 	if (state)
465 		pm_runtime_put_sync_suspend(port->dev);
466 }
467 
468 #ifdef CONFIG_SERIAL_8250_DMA
469 static bool mtk8250_dma_filter(struct dma_chan *chan, void *param)
470 {
471 	return false;
472 }
473 #endif
474 
475 static int mtk8250_probe_of(struct platform_device *pdev, struct uart_port *p,
476 			   struct mtk8250_data *data)
477 {
478 #ifdef CONFIG_SERIAL_8250_DMA
479 	int dmacnt;
480 #endif
481 
482 	data->uart_clk = devm_clk_get_enabled(&pdev->dev, "baud");
483 	if (IS_ERR(data->uart_clk)) {
484 		/*
485 		 * For compatibility with older device trees try unnamed
486 		 * clk when no baud clk can be found.
487 		 */
488 		data->uart_clk = devm_clk_get_enabled(&pdev->dev, NULL);
489 		if (IS_ERR(data->uart_clk)) {
490 			dev_warn(&pdev->dev, "Can't get uart clock\n");
491 			return PTR_ERR(data->uart_clk);
492 		}
493 
494 		return 0;
495 	}
496 
497 	data->bus_clk = devm_clk_get_enabled(&pdev->dev, "bus");
498 	if (IS_ERR(data->bus_clk))
499 		return PTR_ERR(data->bus_clk);
500 
501 	data->dma = NULL;
502 #ifdef CONFIG_SERIAL_8250_DMA
503 	dmacnt = of_property_count_strings(pdev->dev.of_node, "dma-names");
504 	if (dmacnt == 2) {
505 		data->dma = devm_kzalloc(&pdev->dev, sizeof(*data->dma),
506 					 GFP_KERNEL);
507 		if (!data->dma)
508 			return -ENOMEM;
509 
510 		data->dma->fn = mtk8250_dma_filter;
511 		data->dma->rx_size = MTK_UART_RX_SIZE;
512 		data->dma->rxconf.src_maxburst = MTK_UART_RX_TRIGGER;
513 		data->dma->txconf.dst_maxburst = MTK_UART_TX_TRIGGER;
514 	}
515 #endif
516 
517 	return 0;
518 }
519 
520 static int mtk8250_probe(struct platform_device *pdev)
521 {
522 	struct uart_8250_port uart = {};
523 	struct mtk8250_data *data;
524 	struct resource *regs;
525 	int irq, err, line;
526 	struct fwnode_handle *fwnode = dev_fwnode(&pdev->dev);
527 
528 	irq = platform_get_irq(pdev, 0);
529 	if (irq < 0)
530 		return irq;
531 
532 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
533 	if (!regs) {
534 		dev_err(&pdev->dev, "no registers defined\n");
535 		return -EINVAL;
536 	}
537 
538 	uart.port.membase = devm_ioremap(&pdev->dev, regs->start,
539 					 resource_size(regs));
540 	if (!uart.port.membase)
541 		return -ENOMEM;
542 
543 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
544 	if (!data)
545 		return -ENOMEM;
546 
547 	data->clk_count = 0;
548 
549 	if (is_of_node(fwnode)) {
550 		err = mtk8250_probe_of(pdev, &uart.port, data);
551 		if (err)
552 			return err;
553 	} else if (!fwnode) {
554 		return -ENODEV;
555 	}
556 
557 	spin_lock_init(&uart.port.lock);
558 	uart.port.mapbase = regs->start;
559 	uart.port.irq = irq;
560 	uart.port.pm = mtk8250_do_pm;
561 	uart.port.type = PORT_16550;
562 	uart.port.flags = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT;
563 	uart.port.dev = &pdev->dev;
564 	uart.port.iotype = UPIO_MEM32;
565 	uart.port.regshift = 2;
566 	uart.port.private_data = data;
567 	uart.port.shutdown = mtk8250_shutdown;
568 	uart.port.startup = mtk8250_startup;
569 	uart.port.set_termios = mtk8250_set_termios;
570 	uart.port.uartclk = clk_get_rate(data->uart_clk);
571 	if (!uart.port.uartclk)
572 		uart.port.uartclk = 26 * HZ_PER_MHZ;
573 #ifdef CONFIG_SERIAL_8250_DMA
574 	if (data->dma)
575 		uart.dma = data->dma;
576 #endif
577 
578 	if (is_of_node(fwnode)) {
579 		line = of_alias_get_id(pdev->dev.of_node, "serial");
580 		if (line >= 0)
581 			uart.port.line = line;
582 
583 		/* Disable Rate Fix function */
584 		writel(0x0, uart.port.membase +
585 			(MTK_UART_RATE_FIX << uart.port.regshift));
586 	}
587 
588 	platform_set_drvdata(pdev, data);
589 
590 	data->line = serial8250_register_8250_port(&uart);
591 	if (data->line < 0)
592 		return data->line;
593 
594 	data->rx_wakeup_irq = platform_get_irq_optional(pdev, 1);
595 
596 	pm_runtime_set_active(&pdev->dev);
597 	pm_runtime_enable(&pdev->dev);
598 
599 	return 0;
600 }
601 
602 static void mtk8250_remove(struct platform_device *pdev)
603 {
604 	struct mtk8250_data *data = platform_get_drvdata(pdev);
605 
606 	pm_runtime_get_sync(&pdev->dev);
607 
608 	serial8250_unregister_port(data->line);
609 
610 	pm_runtime_disable(&pdev->dev);
611 	pm_runtime_put_noidle(&pdev->dev);
612 }
613 
614 static int __maybe_unused mtk8250_suspend(struct device *dev)
615 {
616 	struct mtk8250_data *data = dev_get_drvdata(dev);
617 	int irq = data->rx_wakeup_irq;
618 	int err;
619 
620 	serial8250_suspend_port(data->line);
621 
622 	pinctrl_pm_select_sleep_state(dev);
623 	if (irq >= 0) {
624 		err = enable_irq_wake(irq);
625 		if (err) {
626 			dev_err(dev,
627 				"failed to enable irq wake on IRQ %d: %d\n",
628 				irq, err);
629 			pinctrl_pm_select_default_state(dev);
630 			serial8250_resume_port(data->line);
631 			return err;
632 		}
633 	}
634 
635 	return 0;
636 }
637 
638 static int __maybe_unused mtk8250_resume(struct device *dev)
639 {
640 	struct mtk8250_data *data = dev_get_drvdata(dev);
641 	int irq = data->rx_wakeup_irq;
642 
643 	if (irq >= 0)
644 		disable_irq_wake(irq);
645 	pinctrl_pm_select_default_state(dev);
646 
647 	serial8250_resume_port(data->line);
648 
649 	return 0;
650 }
651 
652 static const struct dev_pm_ops mtk8250_pm_ops = {
653 	SET_SYSTEM_SLEEP_PM_OPS(mtk8250_suspend, mtk8250_resume)
654 	SET_RUNTIME_PM_OPS(mtk8250_runtime_suspend, mtk8250_runtime_resume,
655 				NULL)
656 };
657 
658 static const struct of_device_id mtk8250_of_match[] = {
659 	{ .compatible = "mediatek,mt6577-uart" },
660 	{ /* Sentinel */ }
661 };
662 MODULE_DEVICE_TABLE(of, mtk8250_of_match);
663 
664 static const struct acpi_device_id mtk8250_acpi_match[] = {
665 	{ "MTKI0511" },
666 	{ "NVDA0240" },
667 	{}
668 };
669 MODULE_DEVICE_TABLE(acpi, mtk8250_acpi_match);
670 
671 static struct platform_driver mtk8250_platform_driver = {
672 	.driver = {
673 		.name		= "mt6577-uart",
674 		.pm		= &mtk8250_pm_ops,
675 		.of_match_table	= mtk8250_of_match,
676 		.acpi_match_table = mtk8250_acpi_match,
677 	},
678 	.probe			= mtk8250_probe,
679 	.remove			= mtk8250_remove,
680 };
681 module_platform_driver(mtk8250_platform_driver);
682 
683 #ifdef CONFIG_SERIAL_8250_CONSOLE
684 static int __init early_mtk8250_setup(struct earlycon_device *device,
685 					const char *options)
686 {
687 	if (!device->port.membase)
688 		return -ENODEV;
689 
690 	device->port.iotype = UPIO_MEM32;
691 	device->port.regshift = 2;
692 
693 	return early_serial8250_setup(device, NULL);
694 }
695 
696 OF_EARLYCON_DECLARE(mtk8250, "mediatek,mt6577-uart", early_mtk8250_setup);
697 #endif
698 
699 MODULE_AUTHOR("Matthias Brugger");
700 MODULE_LICENSE("GPL");
701 MODULE_DESCRIPTION("Mediatek 8250 serial port driver");
702