Linux kernel mirror (for testing)
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linux
1/*
2 * uartlite.c: Serial driver for Xilinx uartlite serial controller
3 *
4 * Copyright (C) 2006 Peter Korsgaard <jacmet@sunsite.dk>
5 * Copyright (C) 2007 Secret Lab Technologies Ltd.
6 *
7 * This file is licensed under the terms of the GNU General Public License
8 * version 2. This program is licensed "as is" without any warranty of any
9 * kind, whether express or implied.
10 */
11
12#include <linux/platform_device.h>
13#include <linux/module.h>
14#include <linux/console.h>
15#include <linux/serial.h>
16#include <linux/serial_core.h>
17#include <linux/tty.h>
18#include <linux/delay.h>
19#include <linux/interrupt.h>
20#include <linux/init.h>
21#include <asm/io.h>
22#if defined(CONFIG_OF)
23#include <linux/of.h>
24#include <linux/of_device.h>
25#include <linux/of_platform.h>
26
27/* Match table for of_platform binding */
28static struct of_device_id ulite_of_match[] __devinitdata = {
29 { .compatible = "xlnx,opb-uartlite-1.00.b", },
30 { .compatible = "xlnx,xps-uartlite-1.00.a", },
31 {}
32};
33MODULE_DEVICE_TABLE(of, ulite_of_match);
34
35#endif
36
37#define ULITE_NAME "ttyUL"
38#define ULITE_MAJOR 204
39#define ULITE_MINOR 187
40#define ULITE_NR_UARTS 4
41
42/* ---------------------------------------------------------------------
43 * Register definitions
44 *
45 * For register details see datasheet:
46 * http://www.xilinx.com/bvdocs/ipcenter/data_sheet/opb_uartlite.pdf
47 */
48
49#define ULITE_RX 0x00
50#define ULITE_TX 0x04
51#define ULITE_STATUS 0x08
52#define ULITE_CONTROL 0x0c
53
54#define ULITE_REGION 16
55
56#define ULITE_STATUS_RXVALID 0x01
57#define ULITE_STATUS_RXFULL 0x02
58#define ULITE_STATUS_TXEMPTY 0x04
59#define ULITE_STATUS_TXFULL 0x08
60#define ULITE_STATUS_IE 0x10
61#define ULITE_STATUS_OVERRUN 0x20
62#define ULITE_STATUS_FRAME 0x40
63#define ULITE_STATUS_PARITY 0x80
64
65#define ULITE_CONTROL_RST_TX 0x01
66#define ULITE_CONTROL_RST_RX 0x02
67#define ULITE_CONTROL_IE 0x10
68
69
70static struct uart_port ulite_ports[ULITE_NR_UARTS];
71
72/* ---------------------------------------------------------------------
73 * Core UART driver operations
74 */
75
76static int ulite_receive(struct uart_port *port, int stat)
77{
78 struct tty_struct *tty = port->info->port.tty;
79 unsigned char ch = 0;
80 char flag = TTY_NORMAL;
81
82 if ((stat & (ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
83 | ULITE_STATUS_FRAME)) == 0)
84 return 0;
85
86 /* stats */
87 if (stat & ULITE_STATUS_RXVALID) {
88 port->icount.rx++;
89 ch = readb(port->membase + ULITE_RX);
90
91 if (stat & ULITE_STATUS_PARITY)
92 port->icount.parity++;
93 }
94
95 if (stat & ULITE_STATUS_OVERRUN)
96 port->icount.overrun++;
97
98 if (stat & ULITE_STATUS_FRAME)
99 port->icount.frame++;
100
101
102 /* drop byte with parity error if IGNPAR specificed */
103 if (stat & port->ignore_status_mask & ULITE_STATUS_PARITY)
104 stat &= ~ULITE_STATUS_RXVALID;
105
106 stat &= port->read_status_mask;
107
108 if (stat & ULITE_STATUS_PARITY)
109 flag = TTY_PARITY;
110
111
112 stat &= ~port->ignore_status_mask;
113
114 if (stat & ULITE_STATUS_RXVALID)
115 tty_insert_flip_char(tty, ch, flag);
116
117 if (stat & ULITE_STATUS_FRAME)
118 tty_insert_flip_char(tty, 0, TTY_FRAME);
119
120 if (stat & ULITE_STATUS_OVERRUN)
121 tty_insert_flip_char(tty, 0, TTY_OVERRUN);
122
123 return 1;
124}
125
126static int ulite_transmit(struct uart_port *port, int stat)
127{
128 struct circ_buf *xmit = &port->info->xmit;
129
130 if (stat & ULITE_STATUS_TXFULL)
131 return 0;
132
133 if (port->x_char) {
134 writeb(port->x_char, port->membase + ULITE_TX);
135 port->x_char = 0;
136 port->icount.tx++;
137 return 1;
138 }
139
140 if (uart_circ_empty(xmit) || uart_tx_stopped(port))
141 return 0;
142
143 writeb(xmit->buf[xmit->tail], port->membase + ULITE_TX);
144 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE-1);
145 port->icount.tx++;
146
147 /* wake up */
148 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
149 uart_write_wakeup(port);
150
151 return 1;
152}
153
154static irqreturn_t ulite_isr(int irq, void *dev_id)
155{
156 struct uart_port *port = dev_id;
157 int busy;
158
159 do {
160 int stat = readb(port->membase + ULITE_STATUS);
161 busy = ulite_receive(port, stat);
162 busy |= ulite_transmit(port, stat);
163 } while (busy);
164
165 tty_flip_buffer_push(port->info->port.tty);
166
167 return IRQ_HANDLED;
168}
169
170static unsigned int ulite_tx_empty(struct uart_port *port)
171{
172 unsigned long flags;
173 unsigned int ret;
174
175 spin_lock_irqsave(&port->lock, flags);
176 ret = readb(port->membase + ULITE_STATUS);
177 spin_unlock_irqrestore(&port->lock, flags);
178
179 return ret & ULITE_STATUS_TXEMPTY ? TIOCSER_TEMT : 0;
180}
181
182static unsigned int ulite_get_mctrl(struct uart_port *port)
183{
184 return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
185}
186
187static void ulite_set_mctrl(struct uart_port *port, unsigned int mctrl)
188{
189 /* N/A */
190}
191
192static void ulite_stop_tx(struct uart_port *port)
193{
194 /* N/A */
195}
196
197static void ulite_start_tx(struct uart_port *port)
198{
199 ulite_transmit(port, readb(port->membase + ULITE_STATUS));
200}
201
202static void ulite_stop_rx(struct uart_port *port)
203{
204 /* don't forward any more data (like !CREAD) */
205 port->ignore_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
206 | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
207}
208
209static void ulite_enable_ms(struct uart_port *port)
210{
211 /* N/A */
212}
213
214static void ulite_break_ctl(struct uart_port *port, int ctl)
215{
216 /* N/A */
217}
218
219static int ulite_startup(struct uart_port *port)
220{
221 int ret;
222
223 ret = request_irq(port->irq, ulite_isr,
224 IRQF_DISABLED | IRQF_SAMPLE_RANDOM, "uartlite", port);
225 if (ret)
226 return ret;
227
228 writeb(ULITE_CONTROL_RST_RX | ULITE_CONTROL_RST_TX,
229 port->membase + ULITE_CONTROL);
230 writeb(ULITE_CONTROL_IE, port->membase + ULITE_CONTROL);
231
232 return 0;
233}
234
235static void ulite_shutdown(struct uart_port *port)
236{
237 writeb(0, port->membase + ULITE_CONTROL);
238 readb(port->membase + ULITE_CONTROL); /* dummy */
239 free_irq(port->irq, port);
240}
241
242static void ulite_set_termios(struct uart_port *port, struct ktermios *termios,
243 struct ktermios *old)
244{
245 unsigned long flags;
246 unsigned int baud;
247
248 spin_lock_irqsave(&port->lock, flags);
249
250 port->read_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
251 | ULITE_STATUS_TXFULL;
252
253 if (termios->c_iflag & INPCK)
254 port->read_status_mask |=
255 ULITE_STATUS_PARITY | ULITE_STATUS_FRAME;
256
257 port->ignore_status_mask = 0;
258 if (termios->c_iflag & IGNPAR)
259 port->ignore_status_mask |= ULITE_STATUS_PARITY
260 | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
261
262 /* ignore all characters if CREAD is not set */
263 if ((termios->c_cflag & CREAD) == 0)
264 port->ignore_status_mask |=
265 ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
266 | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
267
268 /* update timeout */
269 baud = uart_get_baud_rate(port, termios, old, 0, 460800);
270 uart_update_timeout(port, termios->c_cflag, baud);
271
272 spin_unlock_irqrestore(&port->lock, flags);
273}
274
275static const char *ulite_type(struct uart_port *port)
276{
277 return port->type == PORT_UARTLITE ? "uartlite" : NULL;
278}
279
280static void ulite_release_port(struct uart_port *port)
281{
282 release_mem_region(port->mapbase, ULITE_REGION);
283 iounmap(port->membase);
284 port->membase = NULL;
285}
286
287static int ulite_request_port(struct uart_port *port)
288{
289 pr_debug("ulite console: port=%p; port->mapbase=%llx\n",
290 port, (unsigned long long) port->mapbase);
291
292 if (!request_mem_region(port->mapbase, ULITE_REGION, "uartlite")) {
293 dev_err(port->dev, "Memory region busy\n");
294 return -EBUSY;
295 }
296
297 port->membase = ioremap(port->mapbase, ULITE_REGION);
298 if (!port->membase) {
299 dev_err(port->dev, "Unable to map registers\n");
300 release_mem_region(port->mapbase, ULITE_REGION);
301 return -EBUSY;
302 }
303
304 return 0;
305}
306
307static void ulite_config_port(struct uart_port *port, int flags)
308{
309 if (!ulite_request_port(port))
310 port->type = PORT_UARTLITE;
311}
312
313static int ulite_verify_port(struct uart_port *port, struct serial_struct *ser)
314{
315 /* we don't want the core code to modify any port params */
316 return -EINVAL;
317}
318
319static struct uart_ops ulite_ops = {
320 .tx_empty = ulite_tx_empty,
321 .set_mctrl = ulite_set_mctrl,
322 .get_mctrl = ulite_get_mctrl,
323 .stop_tx = ulite_stop_tx,
324 .start_tx = ulite_start_tx,
325 .stop_rx = ulite_stop_rx,
326 .enable_ms = ulite_enable_ms,
327 .break_ctl = ulite_break_ctl,
328 .startup = ulite_startup,
329 .shutdown = ulite_shutdown,
330 .set_termios = ulite_set_termios,
331 .type = ulite_type,
332 .release_port = ulite_release_port,
333 .request_port = ulite_request_port,
334 .config_port = ulite_config_port,
335 .verify_port = ulite_verify_port
336};
337
338/* ---------------------------------------------------------------------
339 * Console driver operations
340 */
341
342#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
343static void ulite_console_wait_tx(struct uart_port *port)
344{
345 int i;
346 u8 val;
347
348 /* Spin waiting for TX fifo to have space available */
349 for (i = 0; i < 100000; i++) {
350 val = readb(port->membase + ULITE_STATUS);
351 if ((val & ULITE_STATUS_TXFULL) == 0)
352 break;
353 cpu_relax();
354 }
355}
356
357static void ulite_console_putchar(struct uart_port *port, int ch)
358{
359 ulite_console_wait_tx(port);
360 writeb(ch, port->membase + ULITE_TX);
361}
362
363static void ulite_console_write(struct console *co, const char *s,
364 unsigned int count)
365{
366 struct uart_port *port = &ulite_ports[co->index];
367 unsigned long flags;
368 unsigned int ier;
369 int locked = 1;
370
371 if (oops_in_progress) {
372 locked = spin_trylock_irqsave(&port->lock, flags);
373 } else
374 spin_lock_irqsave(&port->lock, flags);
375
376 /* save and disable interrupt */
377 ier = readb(port->membase + ULITE_STATUS) & ULITE_STATUS_IE;
378 writeb(0, port->membase + ULITE_CONTROL);
379
380 uart_console_write(port, s, count, ulite_console_putchar);
381
382 ulite_console_wait_tx(port);
383
384 /* restore interrupt state */
385 if (ier)
386 writeb(ULITE_CONTROL_IE, port->membase + ULITE_CONTROL);
387
388 if (locked)
389 spin_unlock_irqrestore(&port->lock, flags);
390}
391
392static int __init ulite_console_setup(struct console *co, char *options)
393{
394 struct uart_port *port;
395 int baud = 9600;
396 int bits = 8;
397 int parity = 'n';
398 int flow = 'n';
399
400 if (co->index < 0 || co->index >= ULITE_NR_UARTS)
401 return -EINVAL;
402
403 port = &ulite_ports[co->index];
404
405 /* Has the device been initialized yet? */
406 if (!port->mapbase) {
407 pr_debug("console on ttyUL%i not present\n", co->index);
408 return -ENODEV;
409 }
410
411 /* not initialized yet? */
412 if (!port->membase) {
413 if (ulite_request_port(port))
414 return -ENODEV;
415 }
416
417 if (options)
418 uart_parse_options(options, &baud, &parity, &bits, &flow);
419
420 return uart_set_options(port, co, baud, parity, bits, flow);
421}
422
423static struct uart_driver ulite_uart_driver;
424
425static struct console ulite_console = {
426 .name = ULITE_NAME,
427 .write = ulite_console_write,
428 .device = uart_console_device,
429 .setup = ulite_console_setup,
430 .flags = CON_PRINTBUFFER,
431 .index = -1, /* Specified on the cmdline (e.g. console=ttyUL0 ) */
432 .data = &ulite_uart_driver,
433};
434
435static int __init ulite_console_init(void)
436{
437 register_console(&ulite_console);
438 return 0;
439}
440
441console_initcall(ulite_console_init);
442
443#endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */
444
445static struct uart_driver ulite_uart_driver = {
446 .owner = THIS_MODULE,
447 .driver_name = "uartlite",
448 .dev_name = ULITE_NAME,
449 .major = ULITE_MAJOR,
450 .minor = ULITE_MINOR,
451 .nr = ULITE_NR_UARTS,
452#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
453 .cons = &ulite_console,
454#endif
455};
456
457/* ---------------------------------------------------------------------
458 * Port assignment functions (mapping devices to uart_port structures)
459 */
460
461/** ulite_assign: register a uartlite device with the driver
462 *
463 * @dev: pointer to device structure
464 * @id: requested id number. Pass -1 for automatic port assignment
465 * @base: base address of uartlite registers
466 * @irq: irq number for uartlite
467 *
468 * Returns: 0 on success, <0 otherwise
469 */
470static int __devinit ulite_assign(struct device *dev, int id, u32 base, int irq)
471{
472 struct uart_port *port;
473 int rc;
474
475 /* if id = -1; then scan for a free id and use that */
476 if (id < 0) {
477 for (id = 0; id < ULITE_NR_UARTS; id++)
478 if (ulite_ports[id].mapbase == 0)
479 break;
480 }
481 if (id < 0 || id >= ULITE_NR_UARTS) {
482 dev_err(dev, "%s%i too large\n", ULITE_NAME, id);
483 return -EINVAL;
484 }
485
486 if ((ulite_ports[id].mapbase) && (ulite_ports[id].mapbase != base)) {
487 dev_err(dev, "cannot assign to %s%i; it is already in use\n",
488 ULITE_NAME, id);
489 return -EBUSY;
490 }
491
492 port = &ulite_ports[id];
493
494 spin_lock_init(&port->lock);
495 port->fifosize = 16;
496 port->regshift = 2;
497 port->iotype = UPIO_MEM;
498 port->iobase = 1; /* mark port in use */
499 port->mapbase = base;
500 port->membase = NULL;
501 port->ops = &ulite_ops;
502 port->irq = irq;
503 port->flags = UPF_BOOT_AUTOCONF;
504 port->dev = dev;
505 port->type = PORT_UNKNOWN;
506 port->line = id;
507
508 dev_set_drvdata(dev, port);
509
510 /* Register the port */
511 rc = uart_add_one_port(&ulite_uart_driver, port);
512 if (rc) {
513 dev_err(dev, "uart_add_one_port() failed; err=%i\n", rc);
514 port->mapbase = 0;
515 dev_set_drvdata(dev, NULL);
516 return rc;
517 }
518
519 return 0;
520}
521
522/** ulite_release: register a uartlite device with the driver
523 *
524 * @dev: pointer to device structure
525 */
526static int __devexit ulite_release(struct device *dev)
527{
528 struct uart_port *port = dev_get_drvdata(dev);
529 int rc = 0;
530
531 if (port) {
532 rc = uart_remove_one_port(&ulite_uart_driver, port);
533 dev_set_drvdata(dev, NULL);
534 port->mapbase = 0;
535 }
536
537 return rc;
538}
539
540/* ---------------------------------------------------------------------
541 * Platform bus binding
542 */
543
544static int __devinit ulite_probe(struct platform_device *pdev)
545{
546 struct resource *res, *res2;
547
548 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
549 if (!res)
550 return -ENODEV;
551
552 res2 = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
553 if (!res2)
554 return -ENODEV;
555
556 return ulite_assign(&pdev->dev, pdev->id, res->start, res2->start);
557}
558
559static int __devexit ulite_remove(struct platform_device *pdev)
560{
561 return ulite_release(&pdev->dev);
562}
563
564/* work with hotplug and coldplug */
565MODULE_ALIAS("platform:uartlite");
566
567static struct platform_driver ulite_platform_driver = {
568 .probe = ulite_probe,
569 .remove = __devexit_p(ulite_remove),
570 .driver = {
571 .owner = THIS_MODULE,
572 .name = "uartlite",
573 },
574};
575
576/* ---------------------------------------------------------------------
577 * OF bus bindings
578 */
579#if defined(CONFIG_OF)
580static int __devinit
581ulite_of_probe(struct of_device *op, const struct of_device_id *match)
582{
583 struct resource res;
584 const unsigned int *id;
585 int irq, rc;
586
587 dev_dbg(&op->dev, "%s(%p, %p)\n", __func__, op, match);
588
589 rc = of_address_to_resource(op->node, 0, &res);
590 if (rc) {
591 dev_err(&op->dev, "invalid address\n");
592 return rc;
593 }
594
595 irq = irq_of_parse_and_map(op->node, 0);
596
597 id = of_get_property(op->node, "port-number", NULL);
598
599 return ulite_assign(&op->dev, id ? *id : -1, res.start+3, irq);
600}
601
602static int __devexit ulite_of_remove(struct of_device *op)
603{
604 return ulite_release(&op->dev);
605}
606
607static struct of_platform_driver ulite_of_driver = {
608 .owner = THIS_MODULE,
609 .name = "uartlite",
610 .match_table = ulite_of_match,
611 .probe = ulite_of_probe,
612 .remove = __devexit_p(ulite_of_remove),
613 .driver = {
614 .name = "uartlite",
615 },
616};
617
618/* Registration helpers to keep the number of #ifdefs to a minimum */
619static inline int __init ulite_of_register(void)
620{
621 pr_debug("uartlite: calling of_register_platform_driver()\n");
622 return of_register_platform_driver(&ulite_of_driver);
623}
624
625static inline void __exit ulite_of_unregister(void)
626{
627 of_unregister_platform_driver(&ulite_of_driver);
628}
629#else /* CONFIG_OF */
630/* CONFIG_OF not enabled; do nothing helpers */
631static inline int __init ulite_of_register(void) { return 0; }
632static inline void __exit ulite_of_unregister(void) { }
633#endif /* CONFIG_OF */
634
635/* ---------------------------------------------------------------------
636 * Module setup/teardown
637 */
638
639int __init ulite_init(void)
640{
641 int ret;
642
643 pr_debug("uartlite: calling uart_register_driver()\n");
644 ret = uart_register_driver(&ulite_uart_driver);
645 if (ret)
646 goto err_uart;
647
648 ret = ulite_of_register();
649 if (ret)
650 goto err_of;
651
652 pr_debug("uartlite: calling platform_driver_register()\n");
653 ret = platform_driver_register(&ulite_platform_driver);
654 if (ret)
655 goto err_plat;
656
657 return 0;
658
659err_plat:
660 ulite_of_unregister();
661err_of:
662 uart_unregister_driver(&ulite_uart_driver);
663err_uart:
664 printk(KERN_ERR "registering uartlite driver failed: err=%i", ret);
665 return ret;
666}
667
668void __exit ulite_exit(void)
669{
670 platform_driver_unregister(&ulite_platform_driver);
671 ulite_of_unregister();
672 uart_unregister_driver(&ulite_uart_driver);
673}
674
675module_init(ulite_init);
676module_exit(ulite_exit);
677
678MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
679MODULE_DESCRIPTION("Xilinx uartlite serial driver");
680MODULE_LICENSE("GPL");