xref: /openbmc/linux/drivers/tty/serial/ar933x_uart.c (revision b6bec26c)
1 /*
2  *  Atheros AR933X SoC built-in UART driver
3  *
4  *  Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
5  *
6  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
7  *
8  *  This program is free software; you can redistribute it and/or modify it
9  *  under the terms of the GNU General Public License version 2 as published
10  *  by the Free Software Foundation.
11  */
12 
13 #include <linux/module.h>
14 #include <linux/ioport.h>
15 #include <linux/init.h>
16 #include <linux/console.h>
17 #include <linux/sysrq.h>
18 #include <linux/delay.h>
19 #include <linux/platform_device.h>
20 #include <linux/tty.h>
21 #include <linux/tty_flip.h>
22 #include <linux/serial_core.h>
23 #include <linux/serial.h>
24 #include <linux/slab.h>
25 #include <linux/io.h>
26 #include <linux/irq.h>
27 
28 #include <asm/div64.h>
29 
30 #include <asm/mach-ath79/ar933x_uart.h>
31 #include <asm/mach-ath79/ar933x_uart_platform.h>
32 
33 #define DRIVER_NAME "ar933x-uart"
34 
35 #define AR933X_UART_MAX_SCALE	0xff
36 #define AR933X_UART_MAX_STEP	0xffff
37 
38 #define AR933X_UART_MIN_BAUD	300
39 #define AR933X_UART_MAX_BAUD	3000000
40 
41 #define AR933X_DUMMY_STATUS_RD	0x01
42 
43 static struct uart_driver ar933x_uart_driver;
44 
45 struct ar933x_uart_port {
46 	struct uart_port	port;
47 	unsigned int		ier;	/* shadow Interrupt Enable Register */
48 	unsigned int		min_baud;
49 	unsigned int		max_baud;
50 };
51 
52 static inline unsigned int ar933x_uart_read(struct ar933x_uart_port *up,
53 					    int offset)
54 {
55 	return readl(up->port.membase + offset);
56 }
57 
58 static inline void ar933x_uart_write(struct ar933x_uart_port *up,
59 				     int offset, unsigned int value)
60 {
61 	writel(value, up->port.membase + offset);
62 }
63 
64 static inline void ar933x_uart_rmw(struct ar933x_uart_port *up,
65 				  unsigned int offset,
66 				  unsigned int mask,
67 				  unsigned int val)
68 {
69 	unsigned int t;
70 
71 	t = ar933x_uart_read(up, offset);
72 	t &= ~mask;
73 	t |= val;
74 	ar933x_uart_write(up, offset, t);
75 }
76 
77 static inline void ar933x_uart_rmw_set(struct ar933x_uart_port *up,
78 				       unsigned int offset,
79 				       unsigned int val)
80 {
81 	ar933x_uart_rmw(up, offset, 0, val);
82 }
83 
84 static inline void ar933x_uart_rmw_clear(struct ar933x_uart_port *up,
85 					 unsigned int offset,
86 					 unsigned int val)
87 {
88 	ar933x_uart_rmw(up, offset, val, 0);
89 }
90 
91 static inline void ar933x_uart_start_tx_interrupt(struct ar933x_uart_port *up)
92 {
93 	up->ier |= AR933X_UART_INT_TX_EMPTY;
94 	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
95 }
96 
97 static inline void ar933x_uart_stop_tx_interrupt(struct ar933x_uart_port *up)
98 {
99 	up->ier &= ~AR933X_UART_INT_TX_EMPTY;
100 	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
101 }
102 
103 static inline void ar933x_uart_putc(struct ar933x_uart_port *up, int ch)
104 {
105 	unsigned int rdata;
106 
107 	rdata = ch & AR933X_UART_DATA_TX_RX_MASK;
108 	rdata |= AR933X_UART_DATA_TX_CSR;
109 	ar933x_uart_write(up, AR933X_UART_DATA_REG, rdata);
110 }
111 
112 static unsigned int ar933x_uart_tx_empty(struct uart_port *port)
113 {
114 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
115 	unsigned long flags;
116 	unsigned int rdata;
117 
118 	spin_lock_irqsave(&up->port.lock, flags);
119 	rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
120 	spin_unlock_irqrestore(&up->port.lock, flags);
121 
122 	return (rdata & AR933X_UART_DATA_TX_CSR) ? 0 : TIOCSER_TEMT;
123 }
124 
125 static unsigned int ar933x_uart_get_mctrl(struct uart_port *port)
126 {
127 	return TIOCM_CAR;
128 }
129 
130 static void ar933x_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
131 {
132 }
133 
134 static void ar933x_uart_start_tx(struct uart_port *port)
135 {
136 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
137 
138 	ar933x_uart_start_tx_interrupt(up);
139 }
140 
141 static void ar933x_uart_stop_tx(struct uart_port *port)
142 {
143 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
144 
145 	ar933x_uart_stop_tx_interrupt(up);
146 }
147 
148 static void ar933x_uart_stop_rx(struct uart_port *port)
149 {
150 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
151 
152 	up->ier &= ~AR933X_UART_INT_RX_VALID;
153 	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
154 }
155 
156 static void ar933x_uart_break_ctl(struct uart_port *port, int break_state)
157 {
158 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
159 	unsigned long flags;
160 
161 	spin_lock_irqsave(&up->port.lock, flags);
162 	if (break_state == -1)
163 		ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
164 				    AR933X_UART_CS_TX_BREAK);
165 	else
166 		ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
167 				      AR933X_UART_CS_TX_BREAK);
168 	spin_unlock_irqrestore(&up->port.lock, flags);
169 }
170 
171 static void ar933x_uart_enable_ms(struct uart_port *port)
172 {
173 }
174 
175 /*
176  * baudrate = (clk / (scale + 1)) * (step * (1 / 2^17))
177  */
178 static unsigned long ar933x_uart_get_baud(unsigned int clk,
179 					  unsigned int scale,
180 					  unsigned int step)
181 {
182 	u64 t;
183 	u32 div;
184 
185 	div = (2 << 16) * (scale + 1);
186 	t = clk;
187 	t *= step;
188 	t += (div / 2);
189 	do_div(t, div);
190 
191 	return t;
192 }
193 
194 static void ar933x_uart_get_scale_step(unsigned int clk,
195 				       unsigned int baud,
196 				       unsigned int *scale,
197 				       unsigned int *step)
198 {
199 	unsigned int tscale;
200 	long min_diff;
201 
202 	*scale = 0;
203 	*step = 0;
204 
205 	min_diff = baud;
206 	for (tscale = 0; tscale < AR933X_UART_MAX_SCALE; tscale++) {
207 		u64 tstep;
208 		int diff;
209 
210 		tstep = baud * (tscale + 1);
211 		tstep *= (2 << 16);
212 		do_div(tstep, clk);
213 
214 		if (tstep > AR933X_UART_MAX_STEP)
215 			break;
216 
217 		diff = abs(ar933x_uart_get_baud(clk, tscale, tstep) - baud);
218 		if (diff < min_diff) {
219 			min_diff = diff;
220 			*scale = tscale;
221 			*step = tstep;
222 		}
223 	}
224 }
225 
226 static void ar933x_uart_set_termios(struct uart_port *port,
227 				    struct ktermios *new,
228 				    struct ktermios *old)
229 {
230 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
231 	unsigned int cs;
232 	unsigned long flags;
233 	unsigned int baud, scale, step;
234 
235 	/* Only CS8 is supported */
236 	new->c_cflag &= ~CSIZE;
237 	new->c_cflag |= CS8;
238 
239 	/* Only one stop bit is supported */
240 	new->c_cflag &= ~CSTOPB;
241 
242 	cs = 0;
243 	if (new->c_cflag & PARENB) {
244 		if (!(new->c_cflag & PARODD))
245 			cs |= AR933X_UART_CS_PARITY_EVEN;
246 		else
247 			cs |= AR933X_UART_CS_PARITY_ODD;
248 	} else {
249 		cs |= AR933X_UART_CS_PARITY_NONE;
250 	}
251 
252 	/* Mark/space parity is not supported */
253 	new->c_cflag &= ~CMSPAR;
254 
255 	baud = uart_get_baud_rate(port, new, old, up->min_baud, up->max_baud);
256 	ar933x_uart_get_scale_step(port->uartclk, baud, &scale, &step);
257 
258 	/*
259 	 * Ok, we're now changing the port state. Do it with
260 	 * interrupts disabled.
261 	 */
262 	spin_lock_irqsave(&up->port.lock, flags);
263 
264 	/* disable the UART */
265 	ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
266 		      AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S);
267 
268 	/* Update the per-port timeout. */
269 	uart_update_timeout(port, new->c_cflag, baud);
270 
271 	up->port.ignore_status_mask = 0;
272 
273 	/* ignore all characters if CREAD is not set */
274 	if ((new->c_cflag & CREAD) == 0)
275 		up->port.ignore_status_mask |= AR933X_DUMMY_STATUS_RD;
276 
277 	ar933x_uart_write(up, AR933X_UART_CLOCK_REG,
278 			  scale << AR933X_UART_CLOCK_SCALE_S | step);
279 
280 	/* setup configuration register */
281 	ar933x_uart_rmw(up, AR933X_UART_CS_REG, AR933X_UART_CS_PARITY_M, cs);
282 
283 	/* enable host interrupt */
284 	ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
285 			    AR933X_UART_CS_HOST_INT_EN);
286 
287 	/* reenable the UART */
288 	ar933x_uart_rmw(up, AR933X_UART_CS_REG,
289 			AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S,
290 			AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S);
291 
292 	spin_unlock_irqrestore(&up->port.lock, flags);
293 
294 	if (tty_termios_baud_rate(new))
295 		tty_termios_encode_baud_rate(new, baud, baud);
296 }
297 
298 static void ar933x_uart_rx_chars(struct ar933x_uart_port *up)
299 {
300 	struct tty_struct *tty;
301 	int max_count = 256;
302 
303 	tty = tty_port_tty_get(&up->port.state->port);
304 	do {
305 		unsigned int rdata;
306 		unsigned char ch;
307 
308 		rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
309 		if ((rdata & AR933X_UART_DATA_RX_CSR) == 0)
310 			break;
311 
312 		/* remove the character from the FIFO */
313 		ar933x_uart_write(up, AR933X_UART_DATA_REG,
314 				  AR933X_UART_DATA_RX_CSR);
315 
316 		if (!tty) {
317 			/* discard the data if no tty available */
318 			continue;
319 		}
320 
321 		up->port.icount.rx++;
322 		ch = rdata & AR933X_UART_DATA_TX_RX_MASK;
323 
324 		if (uart_handle_sysrq_char(&up->port, ch))
325 			continue;
326 
327 		if ((up->port.ignore_status_mask & AR933X_DUMMY_STATUS_RD) == 0)
328 			tty_insert_flip_char(tty, ch, TTY_NORMAL);
329 	} while (max_count-- > 0);
330 
331 	if (tty) {
332 		tty_flip_buffer_push(tty);
333 		tty_kref_put(tty);
334 	}
335 }
336 
337 static void ar933x_uart_tx_chars(struct ar933x_uart_port *up)
338 {
339 	struct circ_buf *xmit = &up->port.state->xmit;
340 	int count;
341 
342 	if (uart_tx_stopped(&up->port))
343 		return;
344 
345 	count = up->port.fifosize;
346 	do {
347 		unsigned int rdata;
348 
349 		rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
350 		if ((rdata & AR933X_UART_DATA_TX_CSR) == 0)
351 			break;
352 
353 		if (up->port.x_char) {
354 			ar933x_uart_putc(up, up->port.x_char);
355 			up->port.icount.tx++;
356 			up->port.x_char = 0;
357 			continue;
358 		}
359 
360 		if (uart_circ_empty(xmit))
361 			break;
362 
363 		ar933x_uart_putc(up, xmit->buf[xmit->tail]);
364 
365 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
366 		up->port.icount.tx++;
367 	} while (--count > 0);
368 
369 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
370 		uart_write_wakeup(&up->port);
371 
372 	if (!uart_circ_empty(xmit))
373 		ar933x_uart_start_tx_interrupt(up);
374 }
375 
376 static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id)
377 {
378 	struct ar933x_uart_port *up = dev_id;
379 	unsigned int status;
380 
381 	status = ar933x_uart_read(up, AR933X_UART_CS_REG);
382 	if ((status & AR933X_UART_CS_HOST_INT) == 0)
383 		return IRQ_NONE;
384 
385 	spin_lock(&up->port.lock);
386 
387 	status = ar933x_uart_read(up, AR933X_UART_INT_REG);
388 	status &= ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
389 
390 	if (status & AR933X_UART_INT_RX_VALID) {
391 		ar933x_uart_write(up, AR933X_UART_INT_REG,
392 				  AR933X_UART_INT_RX_VALID);
393 		ar933x_uart_rx_chars(up);
394 	}
395 
396 	if (status & AR933X_UART_INT_TX_EMPTY) {
397 		ar933x_uart_write(up, AR933X_UART_INT_REG,
398 				  AR933X_UART_INT_TX_EMPTY);
399 		ar933x_uart_stop_tx_interrupt(up);
400 		ar933x_uart_tx_chars(up);
401 	}
402 
403 	spin_unlock(&up->port.lock);
404 
405 	return IRQ_HANDLED;
406 }
407 
408 static int ar933x_uart_startup(struct uart_port *port)
409 {
410 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
411 	unsigned long flags;
412 	int ret;
413 
414 	ret = request_irq(up->port.irq, ar933x_uart_interrupt,
415 			  up->port.irqflags, dev_name(up->port.dev), up);
416 	if (ret)
417 		return ret;
418 
419 	spin_lock_irqsave(&up->port.lock, flags);
420 
421 	/* Enable HOST interrupts */
422 	ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
423 			    AR933X_UART_CS_HOST_INT_EN);
424 
425 	/* Enable RX interrupts */
426 	up->ier = AR933X_UART_INT_RX_VALID;
427 	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
428 
429 	spin_unlock_irqrestore(&up->port.lock, flags);
430 
431 	return 0;
432 }
433 
434 static void ar933x_uart_shutdown(struct uart_port *port)
435 {
436 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
437 
438 	/* Disable all interrupts */
439 	up->ier = 0;
440 	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
441 
442 	/* Disable break condition */
443 	ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
444 			      AR933X_UART_CS_TX_BREAK);
445 
446 	free_irq(up->port.irq, up);
447 }
448 
449 static const char *ar933x_uart_type(struct uart_port *port)
450 {
451 	return (port->type == PORT_AR933X) ? "AR933X UART" : NULL;
452 }
453 
454 static void ar933x_uart_release_port(struct uart_port *port)
455 {
456 	/* Nothing to release ... */
457 }
458 
459 static int ar933x_uart_request_port(struct uart_port *port)
460 {
461 	/* UARTs always present */
462 	return 0;
463 }
464 
465 static void ar933x_uart_config_port(struct uart_port *port, int flags)
466 {
467 	if (flags & UART_CONFIG_TYPE)
468 		port->type = PORT_AR933X;
469 }
470 
471 static int ar933x_uart_verify_port(struct uart_port *port,
472 				   struct serial_struct *ser)
473 {
474 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
475 
476 	if (ser->type != PORT_UNKNOWN &&
477 	    ser->type != PORT_AR933X)
478 		return -EINVAL;
479 
480 	if (ser->irq < 0 || ser->irq >= NR_IRQS)
481 		return -EINVAL;
482 
483 	if (ser->baud_base < up->min_baud ||
484 	    ser->baud_base > up->max_baud)
485 		return -EINVAL;
486 
487 	return 0;
488 }
489 
490 static struct uart_ops ar933x_uart_ops = {
491 	.tx_empty	= ar933x_uart_tx_empty,
492 	.set_mctrl	= ar933x_uart_set_mctrl,
493 	.get_mctrl	= ar933x_uart_get_mctrl,
494 	.stop_tx	= ar933x_uart_stop_tx,
495 	.start_tx	= ar933x_uart_start_tx,
496 	.stop_rx	= ar933x_uart_stop_rx,
497 	.enable_ms	= ar933x_uart_enable_ms,
498 	.break_ctl	= ar933x_uart_break_ctl,
499 	.startup	= ar933x_uart_startup,
500 	.shutdown	= ar933x_uart_shutdown,
501 	.set_termios	= ar933x_uart_set_termios,
502 	.type		= ar933x_uart_type,
503 	.release_port	= ar933x_uart_release_port,
504 	.request_port	= ar933x_uart_request_port,
505 	.config_port	= ar933x_uart_config_port,
506 	.verify_port	= ar933x_uart_verify_port,
507 };
508 
509 #ifdef CONFIG_SERIAL_AR933X_CONSOLE
510 
511 static struct ar933x_uart_port *
512 ar933x_console_ports[CONFIG_SERIAL_AR933X_NR_UARTS];
513 
514 static void ar933x_uart_wait_xmitr(struct ar933x_uart_port *up)
515 {
516 	unsigned int status;
517 	unsigned int timeout = 60000;
518 
519 	/* Wait up to 60ms for the character(s) to be sent. */
520 	do {
521 		status = ar933x_uart_read(up, AR933X_UART_DATA_REG);
522 		if (--timeout == 0)
523 			break;
524 		udelay(1);
525 	} while ((status & AR933X_UART_DATA_TX_CSR) == 0);
526 }
527 
528 static void ar933x_uart_console_putchar(struct uart_port *port, int ch)
529 {
530 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
531 
532 	ar933x_uart_wait_xmitr(up);
533 	ar933x_uart_putc(up, ch);
534 }
535 
536 static void ar933x_uart_console_write(struct console *co, const char *s,
537 				      unsigned int count)
538 {
539 	struct ar933x_uart_port *up = ar933x_console_ports[co->index];
540 	unsigned long flags;
541 	unsigned int int_en;
542 	int locked = 1;
543 
544 	local_irq_save(flags);
545 
546 	if (up->port.sysrq)
547 		locked = 0;
548 	else if (oops_in_progress)
549 		locked = spin_trylock(&up->port.lock);
550 	else
551 		spin_lock(&up->port.lock);
552 
553 	/*
554 	 * First save the IER then disable the interrupts
555 	 */
556 	int_en = ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
557 	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, 0);
558 
559 	uart_console_write(&up->port, s, count, ar933x_uart_console_putchar);
560 
561 	/*
562 	 * Finally, wait for transmitter to become empty
563 	 * and restore the IER
564 	 */
565 	ar933x_uart_wait_xmitr(up);
566 	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, int_en);
567 
568 	ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_ALLINTS);
569 
570 	if (locked)
571 		spin_unlock(&up->port.lock);
572 
573 	local_irq_restore(flags);
574 }
575 
576 static int ar933x_uart_console_setup(struct console *co, char *options)
577 {
578 	struct ar933x_uart_port *up;
579 	int baud = 115200;
580 	int bits = 8;
581 	int parity = 'n';
582 	int flow = 'n';
583 
584 	if (co->index < 0 || co->index >= CONFIG_SERIAL_AR933X_NR_UARTS)
585 		return -EINVAL;
586 
587 	up = ar933x_console_ports[co->index];
588 	if (!up)
589 		return -ENODEV;
590 
591 	if (options)
592 		uart_parse_options(options, &baud, &parity, &bits, &flow);
593 
594 	return uart_set_options(&up->port, co, baud, parity, bits, flow);
595 }
596 
597 static struct console ar933x_uart_console = {
598 	.name		= "ttyATH",
599 	.write		= ar933x_uart_console_write,
600 	.device		= uart_console_device,
601 	.setup		= ar933x_uart_console_setup,
602 	.flags		= CON_PRINTBUFFER,
603 	.index		= -1,
604 	.data		= &ar933x_uart_driver,
605 };
606 
607 static void ar933x_uart_add_console_port(struct ar933x_uart_port *up)
608 {
609 	ar933x_console_ports[up->port.line] = up;
610 }
611 
612 #define AR933X_SERIAL_CONSOLE	(&ar933x_uart_console)
613 
614 #else
615 
616 static inline void ar933x_uart_add_console_port(struct ar933x_uart_port *up) {}
617 
618 #define AR933X_SERIAL_CONSOLE	NULL
619 
620 #endif /* CONFIG_SERIAL_AR933X_CONSOLE */
621 
622 static struct uart_driver ar933x_uart_driver = {
623 	.owner		= THIS_MODULE,
624 	.driver_name	= DRIVER_NAME,
625 	.dev_name	= "ttyATH",
626 	.nr		= CONFIG_SERIAL_AR933X_NR_UARTS,
627 	.cons		= AR933X_SERIAL_CONSOLE,
628 };
629 
630 static int ar933x_uart_probe(struct platform_device *pdev)
631 {
632 	struct ar933x_uart_platform_data *pdata;
633 	struct ar933x_uart_port *up;
634 	struct uart_port *port;
635 	struct resource *mem_res;
636 	struct resource *irq_res;
637 	unsigned int baud;
638 	int id;
639 	int ret;
640 
641 	pdata = pdev->dev.platform_data;
642 	if (!pdata)
643 		return -EINVAL;
644 
645 	id = pdev->id;
646 	if (id == -1)
647 		id = 0;
648 
649 	if (id > CONFIG_SERIAL_AR933X_NR_UARTS)
650 		return -EINVAL;
651 
652 	mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
653 	if (!mem_res) {
654 		dev_err(&pdev->dev, "no MEM resource\n");
655 		return -EINVAL;
656 	}
657 
658 	irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
659 	if (!irq_res) {
660 		dev_err(&pdev->dev, "no IRQ resource\n");
661 		return -EINVAL;
662 	}
663 
664 	up = kzalloc(sizeof(struct ar933x_uart_port), GFP_KERNEL);
665 	if (!up)
666 		return -ENOMEM;
667 
668 	port = &up->port;
669 	port->mapbase = mem_res->start;
670 
671 	port->membase = ioremap(mem_res->start, AR933X_UART_REGS_SIZE);
672 	if (!port->membase) {
673 		ret = -ENOMEM;
674 		goto err_free_up;
675 	}
676 
677 	port->line = id;
678 	port->irq = irq_res->start;
679 	port->dev = &pdev->dev;
680 	port->type = PORT_AR933X;
681 	port->iotype = UPIO_MEM32;
682 	port->uartclk = pdata->uartclk;
683 
684 	port->regshift = 2;
685 	port->fifosize = AR933X_UART_FIFO_SIZE;
686 	port->ops = &ar933x_uart_ops;
687 
688 	baud = ar933x_uart_get_baud(port->uartclk, AR933X_UART_MAX_SCALE, 1);
689 	up->min_baud = max_t(unsigned int, baud, AR933X_UART_MIN_BAUD);
690 
691 	baud = ar933x_uart_get_baud(port->uartclk, 0, AR933X_UART_MAX_STEP);
692 	up->max_baud = min_t(unsigned int, baud, AR933X_UART_MAX_BAUD);
693 
694 	ar933x_uart_add_console_port(up);
695 
696 	ret = uart_add_one_port(&ar933x_uart_driver, &up->port);
697 	if (ret)
698 		goto err_unmap;
699 
700 	platform_set_drvdata(pdev, up);
701 	return 0;
702 
703 err_unmap:
704 	iounmap(up->port.membase);
705 err_free_up:
706 	kfree(up);
707 	return ret;
708 }
709 
710 static int ar933x_uart_remove(struct platform_device *pdev)
711 {
712 	struct ar933x_uart_port *up;
713 
714 	up = platform_get_drvdata(pdev);
715 	platform_set_drvdata(pdev, NULL);
716 
717 	if (up) {
718 		uart_remove_one_port(&ar933x_uart_driver, &up->port);
719 		iounmap(up->port.membase);
720 		kfree(up);
721 	}
722 
723 	return 0;
724 }
725 
726 static struct platform_driver ar933x_uart_platform_driver = {
727 	.probe		= ar933x_uart_probe,
728 	.remove		= ar933x_uart_remove,
729 	.driver		= {
730 		.name		= DRIVER_NAME,
731 		.owner		= THIS_MODULE,
732 	},
733 };
734 
735 static int __init ar933x_uart_init(void)
736 {
737 	int ret;
738 
739 	ar933x_uart_driver.nr = CONFIG_SERIAL_AR933X_NR_UARTS;
740 	ret = uart_register_driver(&ar933x_uart_driver);
741 	if (ret)
742 		goto err_out;
743 
744 	ret = platform_driver_register(&ar933x_uart_platform_driver);
745 	if (ret)
746 		goto err_unregister_uart_driver;
747 
748 	return 0;
749 
750 err_unregister_uart_driver:
751 	uart_unregister_driver(&ar933x_uart_driver);
752 err_out:
753 	return ret;
754 }
755 
756 static void __exit ar933x_uart_exit(void)
757 {
758 	platform_driver_unregister(&ar933x_uart_platform_driver);
759 	uart_unregister_driver(&ar933x_uart_driver);
760 }
761 
762 module_init(ar933x_uart_init);
763 module_exit(ar933x_uart_exit);
764 
765 MODULE_DESCRIPTION("Atheros AR933X UART driver");
766 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
767 MODULE_LICENSE("GPL v2");
768 MODULE_ALIAS("platform:" DRIVER_NAME);
769