ab2ab3c818342d4cb9fd67e402523a26bd696a2f
[linux-2.6.git] / drivers / serial / uartlite.c
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 */
28 static 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 };
33 MODULE_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
70 static struct uart_port ulite_ports[ULITE_NR_UARTS];
71
72 /* ---------------------------------------------------------------------
73  * Core UART driver operations
74  */
75
76 static int ulite_receive(struct uart_port *port, int stat)
77 {
78         struct tty_struct *tty = port->state->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
126 static int ulite_transmit(struct uart_port *port, int stat)
127 {
128         struct circ_buf *xmit  = &port->state->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
154 static irqreturn_t ulite_isr(int irq, void *dev_id)
155 {
156         struct uart_port *port = dev_id;
157         int busy, n = 0;
158
159         do {
160                 int stat = readb(port->membase + ULITE_STATUS);
161                 busy  = ulite_receive(port, stat);
162                 busy |= ulite_transmit(port, stat);
163                 n++;
164         } while (busy);
165
166         /* work done? */
167         if (n > 1) {
168                 tty_flip_buffer_push(port->state->port.tty);
169                 return IRQ_HANDLED;
170         } else {
171                 return IRQ_NONE;
172         }
173 }
174
175 static unsigned int ulite_tx_empty(struct uart_port *port)
176 {
177         unsigned long flags;
178         unsigned int ret;
179
180         spin_lock_irqsave(&port->lock, flags);
181         ret = readb(port->membase + ULITE_STATUS);
182         spin_unlock_irqrestore(&port->lock, flags);
183
184         return ret & ULITE_STATUS_TXEMPTY ? TIOCSER_TEMT : 0;
185 }
186
187 static unsigned int ulite_get_mctrl(struct uart_port *port)
188 {
189         return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
190 }
191
192 static void ulite_set_mctrl(struct uart_port *port, unsigned int mctrl)
193 {
194         /* N/A */
195 }
196
197 static void ulite_stop_tx(struct uart_port *port)
198 {
199         /* N/A */
200 }
201
202 static void ulite_start_tx(struct uart_port *port)
203 {
204         ulite_transmit(port, readb(port->membase + ULITE_STATUS));
205 }
206
207 static void ulite_stop_rx(struct uart_port *port)
208 {
209         /* don't forward any more data (like !CREAD) */
210         port->ignore_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
211                 | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
212 }
213
214 static void ulite_enable_ms(struct uart_port *port)
215 {
216         /* N/A */
217 }
218
219 static void ulite_break_ctl(struct uart_port *port, int ctl)
220 {
221         /* N/A */
222 }
223
224 static int ulite_startup(struct uart_port *port)
225 {
226         int ret;
227
228         ret = request_irq(port->irq, ulite_isr,
229                           IRQF_SHARED | IRQF_SAMPLE_RANDOM, "uartlite", port);
230         if (ret)
231                 return ret;
232
233         writeb(ULITE_CONTROL_RST_RX | ULITE_CONTROL_RST_TX,
234                port->membase + ULITE_CONTROL);
235         writeb(ULITE_CONTROL_IE, port->membase + ULITE_CONTROL);
236
237         return 0;
238 }
239
240 static void ulite_shutdown(struct uart_port *port)
241 {
242         writeb(0, port->membase + ULITE_CONTROL);
243         readb(port->membase + ULITE_CONTROL); /* dummy */
244         free_irq(port->irq, port);
245 }
246
247 static void ulite_set_termios(struct uart_port *port, struct ktermios *termios,
248                               struct ktermios *old)
249 {
250         unsigned long flags;
251         unsigned int baud;
252
253         spin_lock_irqsave(&port->lock, flags);
254
255         port->read_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
256                 | ULITE_STATUS_TXFULL;
257
258         if (termios->c_iflag & INPCK)
259                 port->read_status_mask |=
260                         ULITE_STATUS_PARITY | ULITE_STATUS_FRAME;
261
262         port->ignore_status_mask = 0;
263         if (termios->c_iflag & IGNPAR)
264                 port->ignore_status_mask |= ULITE_STATUS_PARITY
265                         | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
266
267         /* ignore all characters if CREAD is not set */
268         if ((termios->c_cflag & CREAD) == 0)
269                 port->ignore_status_mask |=
270                         ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
271                         | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
272
273         /* update timeout */
274         baud = uart_get_baud_rate(port, termios, old, 0, 460800);
275         uart_update_timeout(port, termios->c_cflag, baud);
276
277         spin_unlock_irqrestore(&port->lock, flags);
278 }
279
280 static const char *ulite_type(struct uart_port *port)
281 {
282         return port->type == PORT_UARTLITE ? "uartlite" : NULL;
283 }
284
285 static void ulite_release_port(struct uart_port *port)
286 {
287         release_mem_region(port->mapbase, ULITE_REGION);
288         iounmap(port->membase);
289         port->membase = NULL;
290 }
291
292 static int ulite_request_port(struct uart_port *port)
293 {
294         pr_debug("ulite console: port=%p; port->mapbase=%llx\n",
295                  port, (unsigned long long) port->mapbase);
296
297         if (!request_mem_region(port->mapbase, ULITE_REGION, "uartlite")) {
298                 dev_err(port->dev, "Memory region busy\n");
299                 return -EBUSY;
300         }
301
302         port->membase = ioremap(port->mapbase, ULITE_REGION);
303         if (!port->membase) {
304                 dev_err(port->dev, "Unable to map registers\n");
305                 release_mem_region(port->mapbase, ULITE_REGION);
306                 return -EBUSY;
307         }
308
309         return 0;
310 }
311
312 static void ulite_config_port(struct uart_port *port, int flags)
313 {
314         if (!ulite_request_port(port))
315                 port->type = PORT_UARTLITE;
316 }
317
318 static int ulite_verify_port(struct uart_port *port, struct serial_struct *ser)
319 {
320         /* we don't want the core code to modify any port params */
321         return -EINVAL;
322 }
323
324 static struct uart_ops ulite_ops = {
325         .tx_empty       = ulite_tx_empty,
326         .set_mctrl      = ulite_set_mctrl,
327         .get_mctrl      = ulite_get_mctrl,
328         .stop_tx        = ulite_stop_tx,
329         .start_tx       = ulite_start_tx,
330         .stop_rx        = ulite_stop_rx,
331         .enable_ms      = ulite_enable_ms,
332         .break_ctl      = ulite_break_ctl,
333         .startup        = ulite_startup,
334         .shutdown       = ulite_shutdown,
335         .set_termios    = ulite_set_termios,
336         .type           = ulite_type,
337         .release_port   = ulite_release_port,
338         .request_port   = ulite_request_port,
339         .config_port    = ulite_config_port,
340         .verify_port    = ulite_verify_port
341 };
342
343 /* ---------------------------------------------------------------------
344  * Console driver operations
345  */
346
347 #ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
348 static void ulite_console_wait_tx(struct uart_port *port)
349 {
350         int i;
351         u8 val;
352
353         /* Spin waiting for TX fifo to have space available */
354         for (i = 0; i < 100000; i++) {
355                 val = readb(port->membase + ULITE_STATUS);
356                 if ((val & ULITE_STATUS_TXFULL) == 0)
357                         break;
358                 cpu_relax();
359         }
360 }
361
362 static void ulite_console_putchar(struct uart_port *port, int ch)
363 {
364         ulite_console_wait_tx(port);
365         writeb(ch, port->membase + ULITE_TX);
366 }
367
368 static void ulite_console_write(struct console *co, const char *s,
369                                 unsigned int count)
370 {
371         struct uart_port *port = &ulite_ports[co->index];
372         unsigned long flags;
373         unsigned int ier;
374         int locked = 1;
375
376         if (oops_in_progress) {
377                 locked = spin_trylock_irqsave(&port->lock, flags);
378         } else
379                 spin_lock_irqsave(&port->lock, flags);
380
381         /* save and disable interrupt */
382         ier = readb(port->membase + ULITE_STATUS) & ULITE_STATUS_IE;
383         writeb(0, port->membase + ULITE_CONTROL);
384
385         uart_console_write(port, s, count, ulite_console_putchar);
386
387         ulite_console_wait_tx(port);
388
389         /* restore interrupt state */
390         if (ier)
391                 writeb(ULITE_CONTROL_IE, port->membase + ULITE_CONTROL);
392
393         if (locked)
394                 spin_unlock_irqrestore(&port->lock, flags);
395 }
396
397 static int __devinit ulite_console_setup(struct console *co, char *options)
398 {
399         struct uart_port *port;
400         int baud = 9600;
401         int bits = 8;
402         int parity = 'n';
403         int flow = 'n';
404
405         if (co->index < 0 || co->index >= ULITE_NR_UARTS)
406                 return -EINVAL;
407
408         port = &ulite_ports[co->index];
409
410         /* Has the device been initialized yet? */
411         if (!port->mapbase) {
412                 pr_debug("console on ttyUL%i not present\n", co->index);
413                 return -ENODEV;
414         }
415
416         /* not initialized yet? */
417         if (!port->membase) {
418                 if (ulite_request_port(port))
419                         return -ENODEV;
420         }
421
422         if (options)
423                 uart_parse_options(options, &baud, &parity, &bits, &flow);
424
425         return uart_set_options(port, co, baud, parity, bits, flow);
426 }
427
428 static struct uart_driver ulite_uart_driver;
429
430 static struct console ulite_console = {
431         .name   = ULITE_NAME,
432         .write  = ulite_console_write,
433         .device = uart_console_device,
434         .setup  = ulite_console_setup,
435         .flags  = CON_PRINTBUFFER,
436         .index  = -1, /* Specified on the cmdline (e.g. console=ttyUL0 ) */
437         .data   = &ulite_uart_driver,
438 };
439
440 static int __init ulite_console_init(void)
441 {
442         register_console(&ulite_console);
443         return 0;
444 }
445
446 console_initcall(ulite_console_init);
447
448 #endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */
449
450 static struct uart_driver ulite_uart_driver = {
451         .owner          = THIS_MODULE,
452         .driver_name    = "uartlite",
453         .dev_name       = ULITE_NAME,
454         .major          = ULITE_MAJOR,
455         .minor          = ULITE_MINOR,
456         .nr             = ULITE_NR_UARTS,
457 #ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
458         .cons           = &ulite_console,
459 #endif
460 };
461
462 /* ---------------------------------------------------------------------
463  * Port assignment functions (mapping devices to uart_port structures)
464  */
465
466 /** ulite_assign: register a uartlite device with the driver
467  *
468  * @dev: pointer to device structure
469  * @id: requested id number.  Pass -1 for automatic port assignment
470  * @base: base address of uartlite registers
471  * @irq: irq number for uartlite
472  *
473  * Returns: 0 on success, <0 otherwise
474  */
475 static int __devinit ulite_assign(struct device *dev, int id, u32 base, int irq)
476 {
477         struct uart_port *port;
478         int rc;
479
480         /* if id = -1; then scan for a free id and use that */
481         if (id < 0) {
482                 for (id = 0; id < ULITE_NR_UARTS; id++)
483                         if (ulite_ports[id].mapbase == 0)
484                                 break;
485         }
486         if (id < 0 || id >= ULITE_NR_UARTS) {
487                 dev_err(dev, "%s%i too large\n", ULITE_NAME, id);
488                 return -EINVAL;
489         }
490
491         if ((ulite_ports[id].mapbase) && (ulite_ports[id].mapbase != base)) {
492                 dev_err(dev, "cannot assign to %s%i; it is already in use\n",
493                         ULITE_NAME, id);
494                 return -EBUSY;
495         }
496
497         port = &ulite_ports[id];
498
499         spin_lock_init(&port->lock);
500         port->fifosize = 16;
501         port->regshift = 2;
502         port->iotype = UPIO_MEM;
503         port->iobase = 1; /* mark port in use */
504         port->mapbase = base;
505         port->membase = NULL;
506         port->ops = &ulite_ops;
507         port->irq = irq;
508         port->flags = UPF_BOOT_AUTOCONF;
509         port->dev = dev;
510         port->type = PORT_UNKNOWN;
511         port->line = id;
512
513         dev_set_drvdata(dev, port);
514
515         /* Register the port */
516         rc = uart_add_one_port(&ulite_uart_driver, port);
517         if (rc) {
518                 dev_err(dev, "uart_add_one_port() failed; err=%i\n", rc);
519                 port->mapbase = 0;
520                 dev_set_drvdata(dev, NULL);
521                 return rc;
522         }
523
524         return 0;
525 }
526
527 /** ulite_release: register a uartlite device with the driver
528  *
529  * @dev: pointer to device structure
530  */
531 static int __devexit ulite_release(struct device *dev)
532 {
533         struct uart_port *port = dev_get_drvdata(dev);
534         int rc = 0;
535
536         if (port) {
537                 rc = uart_remove_one_port(&ulite_uart_driver, port);
538                 dev_set_drvdata(dev, NULL);
539                 port->mapbase = 0;
540         }
541
542         return rc;
543 }
544
545 /* ---------------------------------------------------------------------
546  * Platform bus binding
547  */
548
549 static int __devinit ulite_probe(struct platform_device *pdev)
550 {
551         struct resource *res, *res2;
552
553         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
554         if (!res)
555                 return -ENODEV;
556
557         res2 = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
558         if (!res2)
559                 return -ENODEV;
560
561         return ulite_assign(&pdev->dev, pdev->id, res->start, res2->start);
562 }
563
564 static int __devexit ulite_remove(struct platform_device *pdev)
565 {
566         return ulite_release(&pdev->dev);
567 }
568
569 /* work with hotplug and coldplug */
570 MODULE_ALIAS("platform:uartlite");
571
572 static struct platform_driver ulite_platform_driver = {
573         .probe  = ulite_probe,
574         .remove = __devexit_p(ulite_remove),
575         .driver = {
576                    .owner = THIS_MODULE,
577                    .name  = "uartlite",
578                    },
579 };
580
581 /* ---------------------------------------------------------------------
582  * OF bus bindings
583  */
584 #if defined(CONFIG_OF)
585 static int __devinit
586 ulite_of_probe(struct of_device *op, const struct of_device_id *match)
587 {
588         struct resource res;
589         const unsigned int *id;
590         int irq, rc;
591
592         dev_dbg(&op->dev, "%s(%p, %p)\n", __func__, op, match);
593
594         rc = of_address_to_resource(op->node, 0, &res);
595         if (rc) {
596                 dev_err(&op->dev, "invalid address\n");
597                 return rc;
598         }
599
600         irq = irq_of_parse_and_map(op->node, 0);
601
602         id = of_get_property(op->node, "port-number", NULL);
603
604         return ulite_assign(&op->dev, id ? *id : -1, res.start+3, irq);
605 }
606
607 static int __devexit ulite_of_remove(struct of_device *op)
608 {
609         return ulite_release(&op->dev);
610 }
611
612 static struct of_platform_driver ulite_of_driver = {
613         .owner = THIS_MODULE,
614         .name = "uartlite",
615         .match_table = ulite_of_match,
616         .probe = ulite_of_probe,
617         .remove = __devexit_p(ulite_of_remove),
618         .driver = {
619                 .name = "uartlite",
620         },
621 };
622
623 /* Registration helpers to keep the number of #ifdefs to a minimum */
624 static inline int __init ulite_of_register(void)
625 {
626         pr_debug("uartlite: calling of_register_platform_driver()\n");
627         return of_register_platform_driver(&ulite_of_driver);
628 }
629
630 static inline void __exit ulite_of_unregister(void)
631 {
632         of_unregister_platform_driver(&ulite_of_driver);
633 }
634 #else /* CONFIG_OF */
635 /* CONFIG_OF not enabled; do nothing helpers */
636 static inline int __init ulite_of_register(void) { return 0; }
637 static inline void __exit ulite_of_unregister(void) { }
638 #endif /* CONFIG_OF */
639
640 /* ---------------------------------------------------------------------
641  * Module setup/teardown
642  */
643
644 int __init ulite_init(void)
645 {
646         int ret;
647
648         pr_debug("uartlite: calling uart_register_driver()\n");
649         ret = uart_register_driver(&ulite_uart_driver);
650         if (ret)
651                 goto err_uart;
652
653         ret = ulite_of_register();
654         if (ret)
655                 goto err_of;
656
657         pr_debug("uartlite: calling platform_driver_register()\n");
658         ret = platform_driver_register(&ulite_platform_driver);
659         if (ret)
660                 goto err_plat;
661
662         return 0;
663
664 err_plat:
665         ulite_of_unregister();
666 err_of:
667         uart_unregister_driver(&ulite_uart_driver);
668 err_uart:
669         printk(KERN_ERR "registering uartlite driver failed: err=%i", ret);
670         return ret;
671 }
672
673 void __exit ulite_exit(void)
674 {
675         platform_driver_unregister(&ulite_platform_driver);
676         ulite_of_unregister();
677         uart_unregister_driver(&ulite_uart_driver);
678 }
679
680 module_init(ulite_init);
681 module_exit(ulite_exit);
682
683 MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
684 MODULE_DESCRIPTION("Xilinx uartlite serial driver");
685 MODULE_LICENSE("GPL");