xref: /openbmc/linux/drivers/tty/serial/clps711x.c (revision c4ee0af3) 
1 /*
2  *  Driver for CLPS711x serial ports
3  *
4  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
5  *
6  *  Copyright 1999 ARM Limited
7  *  Copyright (C) 2000 Deep Blue Solutions Ltd.
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  */
14 
15 #if defined(CONFIG_SERIAL_CLPS711X_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
16 #define SUPPORT_SYSRQ
17 #endif
18 
19 #include <linux/module.h>
20 #include <linux/device.h>
21 #include <linux/console.h>
22 #include <linux/serial_core.h>
23 #include <linux/serial.h>
24 #include <linux/io.h>
25 #include <linux/clk.h>
26 #include <linux/tty.h>
27 #include <linux/tty_flip.h>
28 #include <linux/ioport.h>
29 #include <linux/platform_device.h>
30 
31 #include <mach/hardware.h>
32 
33 #define UART_CLPS711X_NAME	"uart-clps711x"
34 #define UART_CLPS711X_NR	2
35 #define UART_CLPS711X_MAJOR	204
36 #define UART_CLPS711X_MINOR	40
37 
38 #define UBRLCR(port)		((port)->line ? UBRLCR2 : UBRLCR1)
39 #define UARTDR(port)		((port)->line ? UARTDR2 : UARTDR1)
40 #define SYSFLG(port)		((port)->line ? SYSFLG2 : SYSFLG1)
41 #define SYSCON(port)		((port)->line ? SYSCON2 : SYSCON1)
42 #define TX_IRQ(port)		((port)->line ? IRQ_UTXINT2 : IRQ_UTXINT1)
43 #define RX_IRQ(port)		((port)->line ? IRQ_URXINT2 : IRQ_URXINT1)
44 
45 struct clps711x_port {
46 	struct uart_driver	uart;
47 	struct clk		*uart_clk;
48 	struct uart_port	port[UART_CLPS711X_NR];
49 	int			tx_enabled[UART_CLPS711X_NR];
50 #ifdef CONFIG_SERIAL_CLPS711X_CONSOLE
51 	struct console		console;
52 #endif
53 };
54 
55 static void uart_clps711x_stop_tx(struct uart_port *port)
56 {
57 	struct clps711x_port *s = dev_get_drvdata(port->dev);
58 
59 	if (s->tx_enabled[port->line]) {
60 		disable_irq(TX_IRQ(port));
61 		s->tx_enabled[port->line] = 0;
62 	}
63 }
64 
65 static void uart_clps711x_start_tx(struct uart_port *port)
66 {
67 	struct clps711x_port *s = dev_get_drvdata(port->dev);
68 
69 	if (!s->tx_enabled[port->line]) {
70 		enable_irq(TX_IRQ(port));
71 		s->tx_enabled[port->line] = 1;
72 	}
73 }
74 
75 static void uart_clps711x_stop_rx(struct uart_port *port)
76 {
77 	disable_irq(RX_IRQ(port));
78 }
79 
80 static void uart_clps711x_enable_ms(struct uart_port *port)
81 {
82 	/* Do nothing */
83 }
84 
85 static irqreturn_t uart_clps711x_int_rx(int irq, void *dev_id)
86 {
87 	struct uart_port *port = dev_id;
88 	unsigned int status, ch, flg;
89 
90 	for (;;) {
91 		status = clps_readl(SYSFLG(port));
92 		if (status & SYSFLG_URXFE)
93 			break;
94 
95 		ch = clps_readw(UARTDR(port));
96 		status = ch & (UARTDR_FRMERR | UARTDR_PARERR | UARTDR_OVERR);
97 		ch &= 0xff;
98 
99 		port->icount.rx++;
100 		flg = TTY_NORMAL;
101 
102 		if (unlikely(status)) {
103 			if (status & UARTDR_PARERR)
104 				port->icount.parity++;
105 			else if (status & UARTDR_FRMERR)
106 				port->icount.frame++;
107 			else if (status & UARTDR_OVERR)
108 				port->icount.overrun++;
109 
110 			status &= port->read_status_mask;
111 
112 			if (status & UARTDR_PARERR)
113 				flg = TTY_PARITY;
114 			else if (status & UARTDR_FRMERR)
115 				flg = TTY_FRAME;
116 			else if (status & UARTDR_OVERR)
117 				flg = TTY_OVERRUN;
118 		}
119 
120 		if (uart_handle_sysrq_char(port, ch))
121 			continue;
122 
123 		if (status & port->ignore_status_mask)
124 			continue;
125 
126 		uart_insert_char(port, status, UARTDR_OVERR, ch, flg);
127 	}
128 
129 	tty_flip_buffer_push(&port->state->port);
130 
131 	return IRQ_HANDLED;
132 }
133 
134 static irqreturn_t uart_clps711x_int_tx(int irq, void *dev_id)
135 {
136 	struct uart_port *port = dev_id;
137 	struct clps711x_port *s = dev_get_drvdata(port->dev);
138 	struct circ_buf *xmit = &port->state->xmit;
139 
140 	if (port->x_char) {
141 		clps_writew(port->x_char, UARTDR(port));
142 		port->icount.tx++;
143 		port->x_char = 0;
144 		return IRQ_HANDLED;
145 	}
146 
147 	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
148 		disable_irq_nosync(TX_IRQ(port));
149 		s->tx_enabled[port->line] = 0;
150 		return IRQ_HANDLED;
151 	}
152 
153 	while (!uart_circ_empty(xmit)) {
154 		clps_writew(xmit->buf[xmit->tail], UARTDR(port));
155 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
156 		port->icount.tx++;
157 		if (clps_readl(SYSFLG(port) & SYSFLG_UTXFF))
158 			break;
159 	}
160 
161 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
162 		uart_write_wakeup(port);
163 
164 	return IRQ_HANDLED;
165 }
166 
167 static unsigned int uart_clps711x_tx_empty(struct uart_port *port)
168 {
169 	return (clps_readl(SYSFLG(port) & SYSFLG_UBUSY)) ? 0 : TIOCSER_TEMT;
170 }
171 
172 static unsigned int uart_clps711x_get_mctrl(struct uart_port *port)
173 {
174 	unsigned int status, result = 0;
175 
176 	if (port->line == 0) {
177 		status = clps_readl(SYSFLG1);
178 		if (status & SYSFLG1_DCD)
179 			result |= TIOCM_CAR;
180 		if (status & SYSFLG1_DSR)
181 			result |= TIOCM_DSR;
182 		if (status & SYSFLG1_CTS)
183 			result |= TIOCM_CTS;
184 	} else
185 		result = TIOCM_DSR | TIOCM_CTS | TIOCM_CAR;
186 
187 	return result;
188 }
189 
190 static void uart_clps711x_set_mctrl(struct uart_port *port, unsigned int mctrl)
191 {
192 	/* Do nothing */
193 }
194 
195 static void uart_clps711x_break_ctl(struct uart_port *port, int break_state)
196 {
197 	unsigned long flags;
198 	unsigned int ubrlcr;
199 
200 	spin_lock_irqsave(&port->lock, flags);
201 
202 	ubrlcr = clps_readl(UBRLCR(port));
203 	if (break_state)
204 		ubrlcr |= UBRLCR_BREAK;
205 	else
206 		ubrlcr &= ~UBRLCR_BREAK;
207 	clps_writel(ubrlcr, UBRLCR(port));
208 
209 	spin_unlock_irqrestore(&port->lock, flags);
210 }
211 
212 static int uart_clps711x_startup(struct uart_port *port)
213 {
214 	struct clps711x_port *s = dev_get_drvdata(port->dev);
215 	int ret;
216 
217 	s->tx_enabled[port->line] = 1;
218 	/* Allocate the IRQs */
219 	ret = devm_request_irq(port->dev, TX_IRQ(port), uart_clps711x_int_tx,
220 			       0, UART_CLPS711X_NAME " TX", port);
221 	if (ret)
222 		return ret;
223 
224 	ret = devm_request_irq(port->dev, RX_IRQ(port), uart_clps711x_int_rx,
225 			       0, UART_CLPS711X_NAME " RX", port);
226 	if (ret) {
227 		devm_free_irq(port->dev, TX_IRQ(port), port);
228 		return ret;
229 	}
230 
231 	/* Disable break */
232 	clps_writel(clps_readl(UBRLCR(port)) & ~UBRLCR_BREAK, UBRLCR(port));
233 
234 	/* Enable the port */
235 	clps_writel(clps_readl(SYSCON(port)) | SYSCON_UARTEN, SYSCON(port));
236 
237 	return 0;
238 }
239 
240 static void uart_clps711x_shutdown(struct uart_port *port)
241 {
242 	/* Free the interrupts */
243 	devm_free_irq(port->dev, TX_IRQ(port), port);
244 	devm_free_irq(port->dev, RX_IRQ(port), port);
245 
246 	/* Disable the port */
247 	clps_writel(clps_readl(SYSCON(port)) & ~SYSCON_UARTEN, SYSCON(port));
248 }
249 
250 static void uart_clps711x_set_termios(struct uart_port *port,
251 				      struct ktermios *termios,
252 				      struct ktermios *old)
253 {
254 	unsigned int ubrlcr, baud, quot;
255 	unsigned long flags;
256 
257 	/* Mask termios capabilities we don't support */
258 	termios->c_cflag &= ~CMSPAR;
259 	termios->c_iflag &= ~(BRKINT | IGNBRK);
260 
261 	/* Ask the core to calculate the divisor for us */
262 	baud = uart_get_baud_rate(port, termios, old, port->uartclk / 4096,
263 						      port->uartclk / 16);
264 	quot = uart_get_divisor(port, baud);
265 
266 	switch (termios->c_cflag & CSIZE) {
267 	case CS5:
268 		ubrlcr = UBRLCR_WRDLEN5;
269 		break;
270 	case CS6:
271 		ubrlcr = UBRLCR_WRDLEN6;
272 		break;
273 	case CS7:
274 		ubrlcr = UBRLCR_WRDLEN7;
275 		break;
276 	case CS8:
277 	default:
278 		ubrlcr = UBRLCR_WRDLEN8;
279 		break;
280 	}
281 
282 	if (termios->c_cflag & CSTOPB)
283 		ubrlcr |= UBRLCR_XSTOP;
284 
285 	if (termios->c_cflag & PARENB) {
286 		ubrlcr |= UBRLCR_PRTEN;
287 		if (!(termios->c_cflag & PARODD))
288 			ubrlcr |= UBRLCR_EVENPRT;
289 	}
290 
291 	/* Enable FIFO */
292 	ubrlcr |= UBRLCR_FIFOEN;
293 
294 	spin_lock_irqsave(&port->lock, flags);
295 
296 	/* Set read status mask */
297 	port->read_status_mask = UARTDR_OVERR;
298 	if (termios->c_iflag & INPCK)
299 		port->read_status_mask |= UARTDR_PARERR | UARTDR_FRMERR;
300 
301 	/* Set status ignore mask */
302 	port->ignore_status_mask = 0;
303 	if (!(termios->c_cflag & CREAD))
304 		port->ignore_status_mask |= UARTDR_OVERR | UARTDR_PARERR |
305 					    UARTDR_FRMERR;
306 
307 	uart_update_timeout(port, termios->c_cflag, baud);
308 
309 	clps_writel(ubrlcr | (quot - 1), UBRLCR(port));
310 
311 	spin_unlock_irqrestore(&port->lock, flags);
312 }
313 
314 static const char *uart_clps711x_type(struct uart_port *port)
315 {
316 	return (port->type == PORT_CLPS711X) ? "CLPS711X" : NULL;
317 }
318 
319 static void uart_clps711x_config_port(struct uart_port *port, int flags)
320 {
321 	if (flags & UART_CONFIG_TYPE)
322 		port->type = PORT_CLPS711X;
323 }
324 
325 static void uart_clps711x_release_port(struct uart_port *port)
326 {
327 	/* Do nothing */
328 }
329 
330 static int uart_clps711x_request_port(struct uart_port *port)
331 {
332 	/* Do nothing */
333 	return 0;
334 }
335 
336 static const struct uart_ops uart_clps711x_ops = {
337 	.tx_empty	= uart_clps711x_tx_empty,
338 	.set_mctrl	= uart_clps711x_set_mctrl,
339 	.get_mctrl	= uart_clps711x_get_mctrl,
340 	.stop_tx	= uart_clps711x_stop_tx,
341 	.start_tx	= uart_clps711x_start_tx,
342 	.stop_rx	= uart_clps711x_stop_rx,
343 	.enable_ms	= uart_clps711x_enable_ms,
344 	.break_ctl	= uart_clps711x_break_ctl,
345 	.startup	= uart_clps711x_startup,
346 	.shutdown	= uart_clps711x_shutdown,
347 	.set_termios	= uart_clps711x_set_termios,
348 	.type		= uart_clps711x_type,
349 	.config_port	= uart_clps711x_config_port,
350 	.release_port	= uart_clps711x_release_port,
351 	.request_port	= uart_clps711x_request_port,
352 };
353 
354 #ifdef CONFIG_SERIAL_CLPS711X_CONSOLE
355 static void uart_clps711x_console_putchar(struct uart_port *port, int ch)
356 {
357 	while (clps_readl(SYSFLG(port)) & SYSFLG_UTXFF)
358 		barrier();
359 
360 	clps_writew(ch, UARTDR(port));
361 }
362 
363 static void uart_clps711x_console_write(struct console *co, const char *c,
364 					unsigned n)
365 {
366 	struct clps711x_port *s = (struct clps711x_port *)co->data;
367 	struct uart_port *port = &s->port[co->index];
368 	u32 syscon;
369 
370 	/* Ensure that the port is enabled */
371 	syscon = clps_readl(SYSCON(port));
372 	clps_writel(syscon | SYSCON_UARTEN, SYSCON(port));
373 
374 	uart_console_write(port, c, n, uart_clps711x_console_putchar);
375 
376 	/* Wait for transmitter to become empty */
377 	while (clps_readl(SYSFLG(port)) & SYSFLG_UBUSY)
378 		barrier();
379 
380 	/* Restore the uart state */
381 	clps_writel(syscon, SYSCON(port));
382 }
383 
384 static void uart_clps711x_console_get_options(struct uart_port *port,
385 					      int *baud, int *parity,
386 					      int *bits)
387 {
388 	if (clps_readl(SYSCON(port)) & SYSCON_UARTEN) {
389 		unsigned int ubrlcr, quot;
390 
391 		ubrlcr = clps_readl(UBRLCR(port));
392 
393 		*parity = 'n';
394 		if (ubrlcr & UBRLCR_PRTEN) {
395 			if (ubrlcr & UBRLCR_EVENPRT)
396 				*parity = 'e';
397 			else
398 				*parity = 'o';
399 		}
400 
401 		if ((ubrlcr & UBRLCR_WRDLEN_MASK) == UBRLCR_WRDLEN7)
402 			*bits = 7;
403 		else
404 			*bits = 8;
405 
406 		quot = ubrlcr & UBRLCR_BAUD_MASK;
407 		*baud = port->uartclk / (16 * (quot + 1));
408 	}
409 }
410 
411 static int uart_clps711x_console_setup(struct console *co, char *options)
412 {
413 	int baud = 38400, bits = 8, parity = 'n', flow = 'n';
414 	struct clps711x_port *s = (struct clps711x_port *)co->data;
415 	struct uart_port *port = &s->port[(co->index > 0) ? co->index : 0];
416 
417 	if (options)
418 		uart_parse_options(options, &baud, &parity, &bits, &flow);
419 	else
420 		uart_clps711x_console_get_options(port, &baud, &parity, &bits);
421 
422 	return uart_set_options(port, co, baud, parity, bits, flow);
423 }
424 #endif
425 
426 static int uart_clps711x_probe(struct platform_device *pdev)
427 {
428 	struct clps711x_port *s;
429 	int ret, i;
430 
431 	s = devm_kzalloc(&pdev->dev, sizeof(struct clps711x_port), GFP_KERNEL);
432 	if (!s) {
433 		dev_err(&pdev->dev, "Error allocating port structure\n");
434 		return -ENOMEM;
435 	}
436 	platform_set_drvdata(pdev, s);
437 
438 	s->uart_clk = devm_clk_get(&pdev->dev, "uart");
439 	if (IS_ERR(s->uart_clk)) {
440 		dev_err(&pdev->dev, "Can't get UART clocks\n");
441 		return PTR_ERR(s->uart_clk);
442 	}
443 
444 	s->uart.owner		= THIS_MODULE;
445 	s->uart.dev_name	= "ttyCL";
446 	s->uart.major		= UART_CLPS711X_MAJOR;
447 	s->uart.minor		= UART_CLPS711X_MINOR;
448 	s->uart.nr		= UART_CLPS711X_NR;
449 #ifdef CONFIG_SERIAL_CLPS711X_CONSOLE
450 	s->uart.cons		= &s->console;
451 	s->uart.cons->device	= uart_console_device;
452 	s->uart.cons->write	= uart_clps711x_console_write;
453 	s->uart.cons->setup	= uart_clps711x_console_setup;
454 	s->uart.cons->flags	= CON_PRINTBUFFER;
455 	s->uart.cons->index	= -1;
456 	s->uart.cons->data	= s;
457 	strcpy(s->uart.cons->name, "ttyCL");
458 #endif
459 	ret = uart_register_driver(&s->uart);
460 	if (ret) {
461 		dev_err(&pdev->dev, "Registering UART driver failed\n");
462 		return ret;
463 	}
464 
465 	for (i = 0; i < UART_CLPS711X_NR; i++) {
466 		s->port[i].line		= i;
467 		s->port[i].dev		= &pdev->dev;
468 		s->port[i].irq		= TX_IRQ(&s->port[i]);
469 		s->port[i].iobase	= SYSCON(&s->port[i]);
470 		s->port[i].type		= PORT_CLPS711X;
471 		s->port[i].fifosize	= 16;
472 		s->port[i].flags	= UPF_SKIP_TEST | UPF_FIXED_TYPE;
473 		s->port[i].uartclk	= clk_get_rate(s->uart_clk);
474 		s->port[i].ops		= &uart_clps711x_ops;
475 		WARN_ON(uart_add_one_port(&s->uart, &s->port[i]));
476 	}
477 
478 	return 0;
479 }
480 
481 static int uart_clps711x_remove(struct platform_device *pdev)
482 {
483 	struct clps711x_port *s = platform_get_drvdata(pdev);
484 	int i;
485 
486 	for (i = 0; i < UART_CLPS711X_NR; i++)
487 		uart_remove_one_port(&s->uart, &s->port[i]);
488 
489 	uart_unregister_driver(&s->uart);
490 
491 	return 0;
492 }
493 
494 static struct platform_driver clps711x_uart_driver = {
495 	.driver = {
496 		.name	= UART_CLPS711X_NAME,
497 		.owner	= THIS_MODULE,
498 	},
499 	.probe	= uart_clps711x_probe,
500 	.remove	= uart_clps711x_remove,
501 };
502 module_platform_driver(clps711x_uart_driver);
503 
504 static struct platform_device clps711x_uart_device = {
505 	.name	= UART_CLPS711X_NAME,
506 };
507 
508 static int __init uart_clps711x_init(void)
509 {
510 	return platform_device_register(&clps711x_uart_device);
511 }
512 module_init(uart_clps711x_init);
513 
514 static void __exit uart_clps711x_exit(void)
515 {
516 	platform_device_unregister(&clps711x_uart_device);
517 }
518 module_exit(uart_clps711x_exit);
519 
520 MODULE_AUTHOR("Deep Blue Solutions Ltd");
521 MODULE_DESCRIPTION("CLPS711X serial driver");
522 MODULE_LICENSE("GPL");
523