Merge branch 'virtex-for-2.6.25' of git://git.secretlab.ca/git/linux-2.6-virtex into...
[sfrench/cifs-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->info->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->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
154 static irqreturn_t ulite_isr(int irq, void *dev_id)
155 {
156         struct uart_port *port = (struct uart_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->tty);
166
167         return IRQ_HANDLED;
168 }
169
170 static 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
182 static unsigned int ulite_get_mctrl(struct uart_port *port)
183 {
184         return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
185 }
186
187 static void ulite_set_mctrl(struct uart_port *port, unsigned int mctrl)
188 {
189         /* N/A */
190 }
191
192 static void ulite_stop_tx(struct uart_port *port)
193 {
194         /* N/A */
195 }
196
197 static void ulite_start_tx(struct uart_port *port)
198 {
199         ulite_transmit(port, readb(port->membase + ULITE_STATUS));
200 }
201
202 static 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
209 static void ulite_enable_ms(struct uart_port *port)
210 {
211         /* N/A */
212 }
213
214 static void ulite_break_ctl(struct uart_port *port, int ctl)
215 {
216         /* N/A */
217 }
218
219 static 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
235 static 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
242 static 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
275 static const char *ulite_type(struct uart_port *port)
276 {
277         return port->type == PORT_UARTLITE ? "uartlite" : NULL;
278 }
279
280 static 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
287 static int ulite_request_port(struct uart_port *port)
288 {
289         pr_debug("ulite console: port=%p; port->mapbase=%x\n",
290                  port, 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
307 static void ulite_config_port(struct uart_port *port, int flags)
308 {
309         if (!ulite_request_port(port))
310                 port->type = PORT_UARTLITE;
311 }
312
313 static 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
319 static 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
343 static 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
357 static 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
363 static 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
392 static 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
423 static struct uart_driver ulite_uart_driver;
424
425 static 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
435 static int __init ulite_console_init(void)
436 {
437         register_console(&ulite_console);
438         return 0;
439 }
440
441 console_initcall(ulite_console_init);
442
443 #endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */
444
445 static 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  */
470 static 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  */
526 static 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
544 static 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
559 static int __devexit ulite_remove(struct platform_device *pdev)
560 {
561         return ulite_release(&pdev->dev);
562 }
563
564 static struct platform_driver ulite_platform_driver = {
565         .probe  = ulite_probe,
566         .remove = __devexit_p(ulite_remove),
567         .driver = {
568                    .owner = THIS_MODULE,
569                    .name  = "uartlite",
570                    },
571 };
572
573 /* ---------------------------------------------------------------------
574  * OF bus bindings
575  */
576 #if defined(CONFIG_OF)
577 static int __devinit
578 ulite_of_probe(struct of_device *op, const struct of_device_id *match)
579 {
580         struct resource res;
581         const unsigned int *id;
582         int irq, rc;
583
584         dev_dbg(&op->dev, "%s(%p, %p)\n", __FUNCTION__, op, match);
585
586         rc = of_address_to_resource(op->node, 0, &res);
587         if (rc) {
588                 dev_err(&op->dev, "invalid address\n");
589                 return rc;
590         }
591
592         irq = irq_of_parse_and_map(op->node, 0);
593
594         id = of_get_property(op->node, "port-number", NULL);
595
596         return ulite_assign(&op->dev, id ? *id : -1, res.start+3, irq);
597 }
598
599 static int __devexit ulite_of_remove(struct of_device *op)
600 {
601         return ulite_release(&op->dev);
602 }
603
604 static struct of_platform_driver ulite_of_driver = {
605         .owner = THIS_MODULE,
606         .name = "uartlite",
607         .match_table = ulite_of_match,
608         .probe = ulite_of_probe,
609         .remove = __devexit_p(ulite_of_remove),
610         .driver = {
611                 .name = "uartlite",
612         },
613 };
614
615 /* Registration helpers to keep the number of #ifdefs to a minimum */
616 static inline int __init ulite_of_register(void)
617 {
618         pr_debug("uartlite: calling of_register_platform_driver()\n");
619         return of_register_platform_driver(&ulite_of_driver);
620 }
621
622 static inline void __exit ulite_of_unregister(void)
623 {
624         of_unregister_platform_driver(&ulite_of_driver);
625 }
626 #else /* CONFIG_OF */
627 /* CONFIG_OF not enabled; do nothing helpers */
628 static inline int __init ulite_of_register(void) { return 0; }
629 static inline void __exit ulite_of_unregister(void) { }
630 #endif /* CONFIG_OF */
631
632 /* ---------------------------------------------------------------------
633  * Module setup/teardown
634  */
635
636 int __init ulite_init(void)
637 {
638         int ret;
639
640         pr_debug("uartlite: calling uart_register_driver()\n");
641         ret = uart_register_driver(&ulite_uart_driver);
642         if (ret)
643                 goto err_uart;
644
645         ret = ulite_of_register();
646         if (ret)
647                 goto err_of;
648
649         pr_debug("uartlite: calling platform_driver_register()\n");
650         ret = platform_driver_register(&ulite_platform_driver);
651         if (ret)
652                 goto err_plat;
653
654         return 0;
655
656 err_plat:
657         ulite_of_unregister();
658 err_of:
659         uart_unregister_driver(&ulite_uart_driver);
660 err_uart:
661         printk(KERN_ERR "registering uartlite driver failed: err=%i", ret);
662         return ret;
663 }
664
665 void __exit ulite_exit(void)
666 {
667         platform_driver_unregister(&ulite_platform_driver);
668         ulite_of_unregister();
669         uart_unregister_driver(&ulite_uart_driver);
670 }
671
672 module_init(ulite_init);
673 module_exit(ulite_exit);
674
675 MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
676 MODULE_DESCRIPTION("Xilinx uartlite serial driver");
677 MODULE_LICENSE("GPL");