1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Sunplus SoC UART driver
4  *
5  * Author: Hammer Hsieh <hammerh0314@gmail.com>
6  *
7  * Note1: This driver is 8250-like uart, but are not register compatible.
8  *
9  * Note2: On some buses, for preventing data incoherence, must do a read
10  * for ensure write made it to hardware. In this driver, function startup
11  * and shutdown did not do a read but only do a write directly. For what?
12  * In Sunplus bus communication between memory bus and peripheral bus with
13  * posted write, it will send a specific command after last write command
14  * to make sure write done. Then memory bus identify the specific command
15  * and send done signal back to master device. After master device received
16  * done signal, then proceed next write command. It is no need to do a read
17  * before write.
18  */
19 #include <linux/clk.h>
20 #include <linux/console.h>
21 #include <linux/interrupt.h>
22 #include <linux/io.h>
23 #include <linux/iopoll.h>
24 #include <linux/module.h>
25 #include <linux/of.h>
26 #include <linux/of_platform.h>
27 #include <linux/platform_device.h>
28 #include <linux/reset.h>
29 #include <linux/serial_core.h>
30 #include <linux/serial_reg.h>
31 #include <linux/sysrq.h>
32 #include <linux/tty.h>
33 #include <linux/tty_flip.h>
34 #include <asm/irq.h>
35 
36 /* Register offsets */
37 #define SUP_UART_DATA			0x00
38 #define SUP_UART_LSR			0x04
39 #define SUP_UART_MSR			0x08
40 #define SUP_UART_LCR			0x0C
41 #define SUP_UART_MCR			0x10
42 #define SUP_UART_DIV_L			0x14
43 #define SUP_UART_DIV_H			0x18
44 #define SUP_UART_ISC			0x1C
45 #define SUP_UART_TX_RESIDUE		0x20
46 #define SUP_UART_RX_RESIDUE		0x24
47 
48 /* Line Status Register bits */
49 #define SUP_UART_LSR_BC			BIT(5) /* break condition status */
50 #define SUP_UART_LSR_FE			BIT(4) /* frame error status */
51 #define SUP_UART_LSR_OE			BIT(3) /* overrun error status */
52 #define SUP_UART_LSR_PE			BIT(2) /* parity error status */
53 #define SUP_UART_LSR_RX			BIT(1) /* 1: receive fifo not empty */
54 #define SUP_UART_LSR_TX			BIT(0) /* 1: transmit fifo is not full */
55 #define SUP_UART_LSR_TX_NOT_FULL	1
56 #define SUP_UART_LSR_BRK_ERROR_BITS	GENMASK(5, 2)
57 
58 /* Line Control Register bits */
59 #define SUP_UART_LCR_SBC		BIT(5) /* select break condition */
60 
61 /* Modem Control Register bits */
62 #define SUP_UART_MCR_RI			BIT(3) /* ring indicator */
63 #define SUP_UART_MCR_DCD		BIT(2) /* data carrier detect */
64 
65 /* Interrupt Status/Control Register bits */
66 #define SUP_UART_ISC_RXM		BIT(5) /* RX interrupt enable */
67 #define SUP_UART_ISC_TXM		BIT(4) /* TX interrupt enable */
68 #define SUP_UART_ISC_RX			BIT(1) /* RX interrupt status */
69 #define SUP_UART_ISC_TX			BIT(0) /* TX interrupt status */
70 
71 #define SUP_DUMMY_READ			BIT(16) /* drop bytes received on a !CREAD port */
72 #define SUP_UART_NR			5
73 
74 struct sunplus_uart_port {
75 	struct uart_port port;
76 	struct clk *clk;
77 	struct reset_control *rstc;
78 };
79 
80 static void sp_uart_put_char(struct uart_port *port, unsigned int ch)
81 {
82 	writel(ch, port->membase + SUP_UART_DATA);
83 }
84 
85 static u32 sunplus_tx_buf_not_full(struct uart_port *port)
86 {
87 	unsigned int lsr = readl(port->membase + SUP_UART_LSR);
88 
89 	return (lsr & SUP_UART_LSR_TX) ? SUP_UART_LSR_TX_NOT_FULL : 0;
90 }
91 
92 static unsigned int sunplus_tx_empty(struct uart_port *port)
93 {
94 	unsigned int lsr = readl(port->membase + SUP_UART_LSR);
95 
96 	return (lsr & UART_LSR_TEMT) ? TIOCSER_TEMT : 0;
97 }
98 
99 static void sunplus_set_mctrl(struct uart_port *port, unsigned int mctrl)
100 {
101 	unsigned int mcr = readl(port->membase + SUP_UART_MCR);
102 
103 	if (mctrl & TIOCM_DTR)
104 		mcr |= UART_MCR_DTR;
105 	else
106 		mcr &= ~UART_MCR_DTR;
107 
108 	if (mctrl & TIOCM_RTS)
109 		mcr |= UART_MCR_RTS;
110 	else
111 		mcr &= ~UART_MCR_RTS;
112 
113 	if (mctrl & TIOCM_CAR)
114 		mcr |= SUP_UART_MCR_DCD;
115 	else
116 		mcr &= ~SUP_UART_MCR_DCD;
117 
118 	if (mctrl & TIOCM_RI)
119 		mcr |= SUP_UART_MCR_RI;
120 	else
121 		mcr &= ~SUP_UART_MCR_RI;
122 
123 	if (mctrl & TIOCM_LOOP)
124 		mcr |= UART_MCR_LOOP;
125 	else
126 		mcr &= ~UART_MCR_LOOP;
127 
128 	writel(mcr, port->membase + SUP_UART_MCR);
129 }
130 
131 static unsigned int sunplus_get_mctrl(struct uart_port *port)
132 {
133 	unsigned int mcr, ret = 0;
134 
135 	mcr = readl(port->membase + SUP_UART_MCR);
136 
137 	if (mcr & UART_MCR_DTR)
138 		ret |= TIOCM_DTR;
139 
140 	if (mcr & UART_MCR_RTS)
141 		ret |= TIOCM_RTS;
142 
143 	if (mcr & SUP_UART_MCR_DCD)
144 		ret |= TIOCM_CAR;
145 
146 	if (mcr & SUP_UART_MCR_RI)
147 		ret |= TIOCM_RI;
148 
149 	if (mcr & UART_MCR_LOOP)
150 		ret |= TIOCM_LOOP;
151 
152 	return ret;
153 }
154 
155 static void sunplus_stop_tx(struct uart_port *port)
156 {
157 	unsigned int isc;
158 
159 	isc = readl(port->membase + SUP_UART_ISC);
160 	isc &= ~SUP_UART_ISC_TXM;
161 	writel(isc, port->membase + SUP_UART_ISC);
162 }
163 
164 static void sunplus_start_tx(struct uart_port *port)
165 {
166 	unsigned int isc;
167 
168 	isc = readl(port->membase + SUP_UART_ISC);
169 	isc |= SUP_UART_ISC_TXM;
170 	writel(isc, port->membase + SUP_UART_ISC);
171 }
172 
173 static void sunplus_stop_rx(struct uart_port *port)
174 {
175 	unsigned int isc;
176 
177 	isc = readl(port->membase + SUP_UART_ISC);
178 	isc &= ~SUP_UART_ISC_RXM;
179 	writel(isc, port->membase + SUP_UART_ISC);
180 }
181 
182 static void sunplus_break_ctl(struct uart_port *port, int ctl)
183 {
184 	unsigned long flags;
185 	unsigned int lcr;
186 
187 	spin_lock_irqsave(&port->lock, flags);
188 
189 	lcr = readl(port->membase + SUP_UART_LCR);
190 
191 	if (ctl)
192 		lcr |= SUP_UART_LCR_SBC; /* start break */
193 	else
194 		lcr &= ~SUP_UART_LCR_SBC; /* stop break */
195 
196 	writel(lcr, port->membase + SUP_UART_LCR);
197 
198 	spin_unlock_irqrestore(&port->lock, flags);
199 }
200 
201 static void transmit_chars(struct uart_port *port)
202 {
203 	struct circ_buf *xmit = &port->state->xmit;
204 
205 	if (port->x_char) {
206 		sp_uart_put_char(port, port->x_char);
207 		port->icount.tx++;
208 		port->x_char = 0;
209 		return;
210 	}
211 
212 	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
213 		sunplus_stop_tx(port);
214 		return;
215 	}
216 
217 	do {
218 		sp_uart_put_char(port, xmit->buf[xmit->tail]);
219 		uart_xmit_advance(port, 1);
220 		if (uart_circ_empty(xmit))
221 			break;
222 	} while (sunplus_tx_buf_not_full(port));
223 
224 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
225 		uart_write_wakeup(port);
226 
227 	if (uart_circ_empty(xmit))
228 		sunplus_stop_tx(port);
229 }
230 
231 static void receive_chars(struct uart_port *port)
232 {
233 	unsigned int lsr = readl(port->membase + SUP_UART_LSR);
234 	unsigned int ch, flag;
235 
236 	do {
237 		ch = readl(port->membase + SUP_UART_DATA);
238 		flag = TTY_NORMAL;
239 		port->icount.rx++;
240 
241 		if (unlikely(lsr & SUP_UART_LSR_BRK_ERROR_BITS)) {
242 			if (lsr & SUP_UART_LSR_BC) {
243 				lsr &= ~(SUP_UART_LSR_FE | SUP_UART_LSR_PE);
244 				port->icount.brk++;
245 				flag = TTY_BREAK;
246 				if (uart_handle_break(port))
247 					goto ignore_char;
248 			} else if (lsr & SUP_UART_LSR_PE) {
249 				port->icount.parity++;
250 				flag = TTY_PARITY;
251 			} else if (lsr & SUP_UART_LSR_FE) {
252 				port->icount.frame++;
253 				flag = TTY_FRAME;
254 			}
255 
256 			if (lsr & SUP_UART_LSR_OE)
257 				port->icount.overrun++;
258 		}
259 
260 		if (port->ignore_status_mask & SUP_DUMMY_READ)
261 			goto ignore_char;
262 
263 		if (uart_handle_sysrq_char(port, ch))
264 			goto ignore_char;
265 
266 		uart_insert_char(port, lsr, SUP_UART_LSR_OE, ch, flag);
267 
268 ignore_char:
269 		lsr = readl(port->membase + SUP_UART_LSR);
270 	} while (lsr & SUP_UART_LSR_RX);
271 
272 	tty_flip_buffer_push(&port->state->port);
273 }
274 
275 static irqreturn_t sunplus_uart_irq(int irq, void *args)
276 {
277 	struct uart_port *port = args;
278 	unsigned int isc;
279 
280 	spin_lock(&port->lock);
281 
282 	isc = readl(port->membase + SUP_UART_ISC);
283 
284 	if (isc & SUP_UART_ISC_RX)
285 		receive_chars(port);
286 
287 	if (isc & SUP_UART_ISC_TX)
288 		transmit_chars(port);
289 
290 	spin_unlock(&port->lock);
291 
292 	return IRQ_HANDLED;
293 }
294 
295 static int sunplus_startup(struct uart_port *port)
296 {
297 	unsigned long flags;
298 	unsigned int isc = 0;
299 	int ret;
300 
301 	ret = request_irq(port->irq, sunplus_uart_irq, 0, "sunplus_uart", port);
302 	if (ret)
303 		return ret;
304 
305 	spin_lock_irqsave(&port->lock, flags);
306 	/* isc define Bit[7:4] int setting, Bit[3:0] int status
307 	 * isc register will clean Bit[3:0] int status after read
308 	 * only do a write to Bit[7:4] int setting
309 	 */
310 	isc |= SUP_UART_ISC_RXM;
311 	writel(isc, port->membase + SUP_UART_ISC);
312 	spin_unlock_irqrestore(&port->lock, flags);
313 
314 	return 0;
315 }
316 
317 static void sunplus_shutdown(struct uart_port *port)
318 {
319 	unsigned long flags;
320 
321 	spin_lock_irqsave(&port->lock, flags);
322 	/* isc define Bit[7:4] int setting, Bit[3:0] int status
323 	 * isc register will clean Bit[3:0] int status after read
324 	 * only do a write to Bit[7:4] int setting
325 	 */
326 	writel(0, port->membase + SUP_UART_ISC); /* disable all interrupt */
327 	spin_unlock_irqrestore(&port->lock, flags);
328 
329 	free_irq(port->irq, port);
330 }
331 
332 static void sunplus_set_termios(struct uart_port *port,
333 				struct ktermios *termios,
334 				const struct ktermios *oldtermios)
335 {
336 	u32 ext, div, div_l, div_h, baud, lcr;
337 	u32 clk = port->uartclk;
338 	unsigned long flags;
339 
340 	baud = uart_get_baud_rate(port, termios, oldtermios, 0, port->uartclk / 16);
341 
342 	/* baud rate = uartclk / ((16 * divisor + 1) + divisor_ext) */
343 	clk += baud >> 1;
344 	div = clk / baud;
345 	ext = div & 0x0F;
346 	div = (div >> 4) - 1;
347 	div_l = (div & 0xFF) | (ext << 12);
348 	div_h = div >> 8;
349 
350 	switch (termios->c_cflag & CSIZE) {
351 	case CS5:
352 		lcr = UART_LCR_WLEN5;
353 		break;
354 	case CS6:
355 		lcr = UART_LCR_WLEN6;
356 		break;
357 	case CS7:
358 		lcr = UART_LCR_WLEN7;
359 		break;
360 	default:
361 		lcr = UART_LCR_WLEN8;
362 		break;
363 	}
364 
365 	if (termios->c_cflag & CSTOPB)
366 		lcr |= UART_LCR_STOP;
367 
368 	if (termios->c_cflag & PARENB) {
369 		lcr |= UART_LCR_PARITY;
370 
371 		if (!(termios->c_cflag & PARODD))
372 			lcr |= UART_LCR_EPAR;
373 	}
374 
375 	spin_lock_irqsave(&port->lock, flags);
376 
377 	uart_update_timeout(port, termios->c_cflag, baud);
378 
379 	port->read_status_mask = 0;
380 	if (termios->c_iflag & INPCK)
381 		port->read_status_mask |= SUP_UART_LSR_PE | SUP_UART_LSR_FE;
382 
383 	if (termios->c_iflag & (BRKINT | PARMRK))
384 		port->read_status_mask |= SUP_UART_LSR_BC;
385 
386 	/* Characters to ignore */
387 	port->ignore_status_mask = 0;
388 	if (termios->c_iflag & IGNPAR)
389 		port->ignore_status_mask |= SUP_UART_LSR_FE | SUP_UART_LSR_PE;
390 
391 	if (termios->c_iflag & IGNBRK) {
392 		port->ignore_status_mask |= SUP_UART_LSR_BC;
393 
394 		if (termios->c_iflag & IGNPAR)
395 			port->ignore_status_mask |= SUP_UART_LSR_OE;
396 	}
397 
398 	/* Ignore all characters if CREAD is not set */
399 	if ((termios->c_cflag & CREAD) == 0) {
400 		port->ignore_status_mask |= SUP_DUMMY_READ;
401 		/* flush rx data FIFO */
402 		writel(0, port->membase + SUP_UART_RX_RESIDUE);
403 	}
404 
405 	/* Settings for baud rate divisor and lcr */
406 	writel(div_h, port->membase + SUP_UART_DIV_H);
407 	writel(div_l, port->membase + SUP_UART_DIV_L);
408 	writel(lcr, port->membase + SUP_UART_LCR);
409 
410 	spin_unlock_irqrestore(&port->lock, flags);
411 }
412 
413 static void sunplus_set_ldisc(struct uart_port *port, struct ktermios *termios)
414 {
415 	int new = termios->c_line;
416 
417 	if (new == N_PPS)
418 		port->flags |= UPF_HARDPPS_CD;
419 	else
420 		port->flags &= ~UPF_HARDPPS_CD;
421 }
422 
423 static const char *sunplus_type(struct uart_port *port)
424 {
425 	return port->type == PORT_SUNPLUS ? "sunplus_uart" : NULL;
426 }
427 
428 static void sunplus_config_port(struct uart_port *port, int type)
429 {
430 	if (type & UART_CONFIG_TYPE)
431 		port->type = PORT_SUNPLUS;
432 }
433 
434 static int sunplus_verify_port(struct uart_port *port, struct serial_struct *ser)
435 {
436 	if (ser->type != PORT_UNKNOWN && ser->type != PORT_SUNPLUS)
437 		return -EINVAL;
438 
439 	return 0;
440 }
441 
442 #if defined(CONFIG_SERIAL_SUNPLUS_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
443 static void wait_for_xmitr(struct uart_port *port)
444 {
445 	unsigned int val;
446 	int ret;
447 
448 	/* Wait while FIFO is full or timeout */
449 	ret = readl_poll_timeout_atomic(port->membase + SUP_UART_LSR, val,
450 					(val & SUP_UART_LSR_TX), 1, 10000);
451 
452 	if (ret == -ETIMEDOUT) {
453 		dev_err(port->dev, "Timeout waiting while UART TX FULL\n");
454 		return;
455 	}
456 }
457 #endif
458 
459 #ifdef CONFIG_CONSOLE_POLL
460 static void sunplus_poll_put_char(struct uart_port *port, unsigned char data)
461 {
462 	wait_for_xmitr(port);
463 	sp_uart_put_char(port, data);
464 }
465 
466 static int sunplus_poll_get_char(struct uart_port *port)
467 {
468 	unsigned int lsr = readl(port->membase + SUP_UART_LSR);
469 
470 	if (!(lsr & SUP_UART_LSR_RX))
471 		return NO_POLL_CHAR;
472 
473 	return readl(port->membase + SUP_UART_DATA);
474 }
475 #endif
476 
477 static const struct uart_ops sunplus_uart_ops = {
478 	.tx_empty	= sunplus_tx_empty,
479 	.set_mctrl	= sunplus_set_mctrl,
480 	.get_mctrl	= sunplus_get_mctrl,
481 	.stop_tx	= sunplus_stop_tx,
482 	.start_tx	= sunplus_start_tx,
483 	.stop_rx	= sunplus_stop_rx,
484 	.break_ctl	= sunplus_break_ctl,
485 	.startup	= sunplus_startup,
486 	.shutdown	= sunplus_shutdown,
487 	.set_termios	= sunplus_set_termios,
488 	.set_ldisc	= sunplus_set_ldisc,
489 	.type		= sunplus_type,
490 	.config_port	= sunplus_config_port,
491 	.verify_port	= sunplus_verify_port,
492 #ifdef CONFIG_CONSOLE_POLL
493 	.poll_put_char	= sunplus_poll_put_char,
494 	.poll_get_char	= sunplus_poll_get_char,
495 #endif
496 };
497 
498 #ifdef CONFIG_SERIAL_SUNPLUS_CONSOLE
499 static struct sunplus_uart_port *sunplus_console_ports[SUP_UART_NR];
500 
501 static void sunplus_uart_console_putchar(struct uart_port *port,
502 					 unsigned char ch)
503 {
504 	wait_for_xmitr(port);
505 	sp_uart_put_char(port, ch);
506 }
507 
508 static void sunplus_console_write(struct console *co,
509 				  const char *s,
510 				  unsigned int count)
511 {
512 	unsigned long flags;
513 	int locked = 1;
514 
515 	local_irq_save(flags);
516 
517 	if (sunplus_console_ports[co->index]->port.sysrq)
518 		locked = 0;
519 	else if (oops_in_progress)
520 		locked = spin_trylock(&sunplus_console_ports[co->index]->port.lock);
521 	else
522 		spin_lock(&sunplus_console_ports[co->index]->port.lock);
523 
524 	uart_console_write(&sunplus_console_ports[co->index]->port, s, count,
525 			   sunplus_uart_console_putchar);
526 
527 	if (locked)
528 		spin_unlock(&sunplus_console_ports[co->index]->port.lock);
529 
530 	local_irq_restore(flags);
531 }
532 
533 static int __init sunplus_console_setup(struct console *co, char *options)
534 {
535 	struct sunplus_uart_port *sup;
536 	int baud = 115200;
537 	int bits = 8;
538 	int parity = 'n';
539 	int flow = 'n';
540 
541 	if (co->index < 0 || co->index >= SUP_UART_NR)
542 		return -EINVAL;
543 
544 	sup = sunplus_console_ports[co->index];
545 	if (!sup)
546 		return -ENODEV;
547 
548 	if (options)
549 		uart_parse_options(options, &baud, &parity, &bits, &flow);
550 
551 	return uart_set_options(&sup->port, co, baud, parity, bits, flow);
552 }
553 
554 static struct uart_driver sunplus_uart_driver;
555 static struct console sunplus_uart_console = {
556 	.name		= "ttySUP",
557 	.write		= sunplus_console_write,
558 	.device		= uart_console_device,
559 	.setup		= sunplus_console_setup,
560 	.flags		= CON_PRINTBUFFER,
561 	.index		= -1,
562 	.data		= &sunplus_uart_driver
563 };
564 
565 #define	SERIAL_SUNPLUS_CONSOLE	(&sunplus_uart_console)
566 #else
567 #define	SERIAL_SUNPLUS_CONSOLE	NULL
568 #endif
569 
570 static struct uart_driver sunplus_uart_driver = {
571 	.owner		= THIS_MODULE,
572 	.driver_name	= "sunplus_uart",
573 	.dev_name	= "ttySUP",
574 	.major		= TTY_MAJOR,
575 	.minor		= 64,
576 	.nr		= SUP_UART_NR,
577 	.cons		= SERIAL_SUNPLUS_CONSOLE,
578 };
579 
580 static void sunplus_uart_disable_unprepare(void *data)
581 {
582 	clk_disable_unprepare(data);
583 }
584 
585 static void sunplus_uart_reset_control_assert(void *data)
586 {
587 	reset_control_assert(data);
588 }
589 
590 static int sunplus_uart_probe(struct platform_device *pdev)
591 {
592 	struct sunplus_uart_port *sup;
593 	struct uart_port *port;
594 	struct resource *res;
595 	int ret, irq;
596 
597 	pdev->id = of_alias_get_id(pdev->dev.of_node, "serial");
598 
599 	if (pdev->id < 0 || pdev->id >= SUP_UART_NR)
600 		return -EINVAL;
601 
602 	sup = devm_kzalloc(&pdev->dev, sizeof(*sup), GFP_KERNEL);
603 	if (!sup)
604 		return -ENOMEM;
605 
606 	sup->clk = devm_clk_get_optional(&pdev->dev, NULL);
607 	if (IS_ERR(sup->clk))
608 		return dev_err_probe(&pdev->dev, PTR_ERR(sup->clk), "clk not found\n");
609 
610 	ret = clk_prepare_enable(sup->clk);
611 	if (ret)
612 		return ret;
613 
614 	ret = devm_add_action_or_reset(&pdev->dev, sunplus_uart_disable_unprepare, sup->clk);
615 	if (ret)
616 		return ret;
617 
618 	sup->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
619 	if (IS_ERR(sup->rstc))
620 		return dev_err_probe(&pdev->dev, PTR_ERR(sup->rstc), "rstc not found\n");
621 
622 	port = &sup->port;
623 
624 	port->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
625 	if (IS_ERR(port->membase))
626 		return dev_err_probe(&pdev->dev, PTR_ERR(port->membase), "membase not found\n");
627 
628 	irq = platform_get_irq(pdev, 0);
629 	if (irq < 0)
630 		return irq;
631 
632 	port->mapbase = res->start;
633 	port->uartclk = clk_get_rate(sup->clk);
634 	port->line = pdev->id;
635 	port->irq = irq;
636 	port->dev = &pdev->dev;
637 	port->iotype = UPIO_MEM;
638 	port->ops = &sunplus_uart_ops;
639 	port->flags = UPF_BOOT_AUTOCONF;
640 	port->fifosize = 128;
641 
642 	ret = reset_control_deassert(sup->rstc);
643 	if (ret)
644 		return ret;
645 
646 	ret = devm_add_action_or_reset(&pdev->dev, sunplus_uart_reset_control_assert, sup->rstc);
647 	if (ret)
648 		return ret;
649 
650 #ifdef CONFIG_SERIAL_SUNPLUS_CONSOLE
651 	sunplus_console_ports[sup->port.line] = sup;
652 #endif
653 
654 	platform_set_drvdata(pdev, &sup->port);
655 
656 	ret = uart_add_one_port(&sunplus_uart_driver, &sup->port);
657 #ifdef CONFIG_SERIAL_SUNPLUS_CONSOLE
658 	if (ret)
659 		sunplus_console_ports[sup->port.line] = NULL;
660 #endif
661 
662 	return ret;
663 }
664 
665 static int sunplus_uart_remove(struct platform_device *pdev)
666 {
667 	struct sunplus_uart_port *sup = platform_get_drvdata(pdev);
668 
669 	uart_remove_one_port(&sunplus_uart_driver, &sup->port);
670 
671 	return 0;
672 }
673 
674 static int __maybe_unused sunplus_uart_suspend(struct device *dev)
675 {
676 	struct sunplus_uart_port *sup = dev_get_drvdata(dev);
677 
678 	if (!uart_console(&sup->port))
679 		uart_suspend_port(&sunplus_uart_driver, &sup->port);
680 
681 	return 0;
682 }
683 
684 static int __maybe_unused sunplus_uart_resume(struct device *dev)
685 {
686 	struct sunplus_uart_port *sup = dev_get_drvdata(dev);
687 
688 	if (!uart_console(&sup->port))
689 		uart_resume_port(&sunplus_uart_driver, &sup->port);
690 
691 	return 0;
692 }
693 
694 static const struct dev_pm_ops sunplus_uart_pm_ops = {
695 	SET_SYSTEM_SLEEP_PM_OPS(sunplus_uart_suspend, sunplus_uart_resume)
696 };
697 
698 static const struct of_device_id sp_uart_of_match[] = {
699 	{ .compatible = "sunplus,sp7021-uart" },
700 	{}
701 };
702 MODULE_DEVICE_TABLE(of, sp_uart_of_match);
703 
704 static struct platform_driver sunplus_uart_platform_driver = {
705 	.probe		= sunplus_uart_probe,
706 	.remove		= sunplus_uart_remove,
707 	.driver = {
708 		.name	= "sunplus_uart",
709 		.of_match_table = sp_uart_of_match,
710 		.pm     = &sunplus_uart_pm_ops,
711 	}
712 };
713 
714 static int __init sunplus_uart_init(void)
715 {
716 	int ret;
717 
718 	ret = uart_register_driver(&sunplus_uart_driver);
719 	if (ret)
720 		return ret;
721 
722 	ret = platform_driver_register(&sunplus_uart_platform_driver);
723 	if (ret)
724 		uart_unregister_driver(&sunplus_uart_driver);
725 
726 	return ret;
727 }
728 module_init(sunplus_uart_init);
729 
730 static void __exit sunplus_uart_exit(void)
731 {
732 	platform_driver_unregister(&sunplus_uart_platform_driver);
733 	uart_unregister_driver(&sunplus_uart_driver);
734 }
735 module_exit(sunplus_uart_exit);
736 
737 #ifdef CONFIG_SERIAL_EARLYCON
738 static void sunplus_uart_putc(struct uart_port *port, unsigned char c)
739 {
740 	unsigned int val;
741 	int ret;
742 
743 	ret = readl_poll_timeout_atomic(port->membase + SUP_UART_LSR, val,
744 					(val & UART_LSR_TEMT), 1, 10000);
745 	if (ret)
746 		return;
747 
748 	writel(c, port->membase + SUP_UART_DATA);
749 }
750 
751 static void sunplus_uart_early_write(struct console *con, const char *s, unsigned int n)
752 {
753 	struct earlycon_device *dev = con->data;
754 
755 	uart_console_write(&dev->port, s, n, sunplus_uart_putc);
756 }
757 
758 static int __init
759 sunplus_uart_early_setup(struct earlycon_device *dev, const char *opt)
760 {
761 	if (!(dev->port.membase || dev->port.iobase))
762 		return -ENODEV;
763 
764 	dev->con->write = sunplus_uart_early_write;
765 
766 	return 0;
767 }
768 OF_EARLYCON_DECLARE(sunplus_uart, "sunplus,sp7021-uart", sunplus_uart_early_setup);
769 #endif
770 
771 MODULE_DESCRIPTION("Sunplus UART driver");
772 MODULE_AUTHOR("Hammer Hsieh <hammerh0314@gmail.com>");
773 MODULE_LICENSE("GPL v2");
774