Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18

Linux/drivers/tty/serial/apbuart.c

  1 /*
  2  *  Driver for GRLIB serial ports (APBUART)
  3  *
  4  *  Based on linux/drivers/serial/amba.c
  5  *
  6  *  Copyright (C) 2000 Deep Blue Solutions Ltd.
  7  *  Copyright (C) 2003 Konrad Eisele <eiselekd@web.de>
  8  *  Copyright (C) 2006 Daniel Hellstrom <daniel@gaisler.com>, Aeroflex Gaisler AB
  9  *  Copyright (C) 2008 Gilead Kutnick <kutnickg@zin-tech.com>
 10  *  Copyright (C) 2009 Kristoffer Glembo <kristoffer@gaisler.com>, Aeroflex Gaisler AB
 11  */
 12 
 13 #if defined(CONFIG_SERIAL_GRLIB_GAISLER_APBUART_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
 14 #define SUPPORT_SYSRQ
 15 #endif
 16 
 17 #include <linux/module.h>
 18 #include <linux/tty.h>
 19 #include <linux/tty_flip.h>
 20 #include <linux/ioport.h>
 21 #include <linux/init.h>
 22 #include <linux/serial.h>
 23 #include <linux/console.h>
 24 #include <linux/sysrq.h>
 25 #include <linux/kthread.h>
 26 #include <linux/device.h>
 27 #include <linux/of.h>
 28 #include <linux/of_device.h>
 29 #include <linux/of_platform.h>
 30 #include <linux/of_irq.h>
 31 #include <linux/platform_device.h>
 32 #include <linux/io.h>
 33 #include <linux/serial_core.h>
 34 #include <asm/irq.h>
 35 
 36 #include "apbuart.h"
 37 
 38 #define SERIAL_APBUART_MAJOR    TTY_MAJOR
 39 #define SERIAL_APBUART_MINOR    64
 40 #define UART_DUMMY_RSR_RX       0x8000  /* for ignore all read */
 41 
 42 static void apbuart_tx_chars(struct uart_port *port);
 43 
 44 static void apbuart_stop_tx(struct uart_port *port)
 45 {
 46         unsigned int cr;
 47 
 48         cr = UART_GET_CTRL(port);
 49         cr &= ~UART_CTRL_TI;
 50         UART_PUT_CTRL(port, cr);
 51 }
 52 
 53 static void apbuart_start_tx(struct uart_port *port)
 54 {
 55         unsigned int cr;
 56 
 57         cr = UART_GET_CTRL(port);
 58         cr |= UART_CTRL_TI;
 59         UART_PUT_CTRL(port, cr);
 60 
 61         if (UART_GET_STATUS(port) & UART_STATUS_THE)
 62                 apbuart_tx_chars(port);
 63 }
 64 
 65 static void apbuart_stop_rx(struct uart_port *port)
 66 {
 67         unsigned int cr;
 68 
 69         cr = UART_GET_CTRL(port);
 70         cr &= ~(UART_CTRL_RI);
 71         UART_PUT_CTRL(port, cr);
 72 }
 73 
 74 static void apbuart_rx_chars(struct uart_port *port)
 75 {
 76         unsigned int status, ch, rsr, flag;
 77         unsigned int max_chars = port->fifosize;
 78 
 79         status = UART_GET_STATUS(port);
 80 
 81         while (UART_RX_DATA(status) && (max_chars--)) {
 82 
 83                 ch = UART_GET_CHAR(port);
 84                 flag = TTY_NORMAL;
 85 
 86                 port->icount.rx++;
 87 
 88                 rsr = UART_GET_STATUS(port) | UART_DUMMY_RSR_RX;
 89                 UART_PUT_STATUS(port, 0);
 90                 if (rsr & UART_STATUS_ERR) {
 91 
 92                         if (rsr & UART_STATUS_BR) {
 93                                 rsr &= ~(UART_STATUS_FE | UART_STATUS_PE);
 94                                 port->icount.brk++;
 95                                 if (uart_handle_break(port))
 96                                         goto ignore_char;
 97                         } else if (rsr & UART_STATUS_PE) {
 98                                 port->icount.parity++;
 99                         } else if (rsr & UART_STATUS_FE) {
100                                 port->icount.frame++;
101                         }
102                         if (rsr & UART_STATUS_OE)
103                                 port->icount.overrun++;
104 
105                         rsr &= port->read_status_mask;
106 
107                         if (rsr & UART_STATUS_PE)
108                                 flag = TTY_PARITY;
109                         else if (rsr & UART_STATUS_FE)
110                                 flag = TTY_FRAME;
111                 }
112 
113                 if (uart_handle_sysrq_char(port, ch))
114                         goto ignore_char;
115 
116                 uart_insert_char(port, rsr, UART_STATUS_OE, ch, flag);
117 
118 
119               ignore_char:
120                 status = UART_GET_STATUS(port);
121         }
122 
123         spin_unlock(&port->lock);
124         tty_flip_buffer_push(&port->state->port);
125         spin_lock(&port->lock);
126 }
127 
128 static void apbuart_tx_chars(struct uart_port *port)
129 {
130         struct circ_buf *xmit = &port->state->xmit;
131         int count;
132 
133         if (port->x_char) {
134                 UART_PUT_CHAR(port, port->x_char);
135                 port->icount.tx++;
136                 port->x_char = 0;
137                 return;
138         }
139 
140         if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
141                 apbuart_stop_tx(port);
142                 return;
143         }
144 
145         /* amba: fill FIFO */
146         count = port->fifosize >> 1;
147         do {
148                 UART_PUT_CHAR(port, xmit->buf[xmit->tail]);
149                 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
150                 port->icount.tx++;
151                 if (uart_circ_empty(xmit))
152                         break;
153         } while (--count > 0);
154 
155         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
156                 uart_write_wakeup(port);
157 
158         if (uart_circ_empty(xmit))
159                 apbuart_stop_tx(port);
160 }
161 
162 static irqreturn_t apbuart_int(int irq, void *dev_id)
163 {
164         struct uart_port *port = dev_id;
165         unsigned int status;
166 
167         spin_lock(&port->lock);
168 
169         status = UART_GET_STATUS(port);
170         if (status & UART_STATUS_DR)
171                 apbuart_rx_chars(port);
172         if (status & UART_STATUS_THE)
173                 apbuart_tx_chars(port);
174 
175         spin_unlock(&port->lock);
176 
177         return IRQ_HANDLED;
178 }
179 
180 static unsigned int apbuart_tx_empty(struct uart_port *port)
181 {
182         unsigned int status = UART_GET_STATUS(port);
183         return status & UART_STATUS_THE ? TIOCSER_TEMT : 0;
184 }
185 
186 static unsigned int apbuart_get_mctrl(struct uart_port *port)
187 {
188         /* The GRLIB APBUART handles flow control in hardware */
189         return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
190 }
191 
192 static void apbuart_set_mctrl(struct uart_port *port, unsigned int mctrl)
193 {
194         /* The GRLIB APBUART handles flow control in hardware */
195 }
196 
197 static void apbuart_break_ctl(struct uart_port *port, int break_state)
198 {
199         /* We don't support sending break */
200 }
201 
202 static int apbuart_startup(struct uart_port *port)
203 {
204         int retval;
205         unsigned int cr;
206 
207         /* Allocate the IRQ */
208         retval = request_irq(port->irq, apbuart_int, 0, "apbuart", port);
209         if (retval)
210                 return retval;
211 
212         /* Finally, enable interrupts */
213         cr = UART_GET_CTRL(port);
214         UART_PUT_CTRL(port,
215                       cr | UART_CTRL_RE | UART_CTRL_TE |
216                       UART_CTRL_RI | UART_CTRL_TI);
217 
218         return 0;
219 }
220 
221 static void apbuart_shutdown(struct uart_port *port)
222 {
223         unsigned int cr;
224 
225         /* disable all interrupts, disable the port */
226         cr = UART_GET_CTRL(port);
227         UART_PUT_CTRL(port,
228                       cr & ~(UART_CTRL_RE | UART_CTRL_TE |
229                              UART_CTRL_RI | UART_CTRL_TI));
230 
231         /* Free the interrupt */
232         free_irq(port->irq, port);
233 }
234 
235 static void apbuart_set_termios(struct uart_port *port,
236                                 struct ktermios *termios, struct ktermios *old)
237 {
238         unsigned int cr;
239         unsigned long flags;
240         unsigned int baud, quot;
241 
242         /* Ask the core to calculate the divisor for us. */
243         baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
244         if (baud == 0)
245                 panic("invalid baudrate %i\n", port->uartclk / 16);
246 
247         /* uart_get_divisor calc a *16 uart freq, apbuart is *8 */
248         quot = (uart_get_divisor(port, baud)) * 2;
249         cr = UART_GET_CTRL(port);
250         cr &= ~(UART_CTRL_PE | UART_CTRL_PS);
251 
252         if (termios->c_cflag & PARENB) {
253                 cr |= UART_CTRL_PE;
254                 if ((termios->c_cflag & PARODD))
255                         cr |= UART_CTRL_PS;
256         }
257 
258         /* Enable flow control. */
259         if (termios->c_cflag & CRTSCTS)
260                 cr |= UART_CTRL_FL;
261 
262         spin_lock_irqsave(&port->lock, flags);
263 
264         /* Update the per-port timeout. */
265         uart_update_timeout(port, termios->c_cflag, baud);
266 
267         port->read_status_mask = UART_STATUS_OE;
268         if (termios->c_iflag & INPCK)
269                 port->read_status_mask |= UART_STATUS_FE | UART_STATUS_PE;
270 
271         /* Characters to ignore */
272         port->ignore_status_mask = 0;
273         if (termios->c_iflag & IGNPAR)
274                 port->ignore_status_mask |= UART_STATUS_FE | UART_STATUS_PE;
275 
276         /* Ignore all characters if CREAD is not set. */
277         if ((termios->c_cflag & CREAD) == 0)
278                 port->ignore_status_mask |= UART_DUMMY_RSR_RX;
279 
280         /* Set baud rate */
281         quot -= 1;
282         UART_PUT_SCAL(port, quot);
283         UART_PUT_CTRL(port, cr);
284 
285         spin_unlock_irqrestore(&port->lock, flags);
286 }
287 
288 static const char *apbuart_type(struct uart_port *port)
289 {
290         return port->type == PORT_APBUART ? "GRLIB/APBUART" : NULL;
291 }
292 
293 static void apbuart_release_port(struct uart_port *port)
294 {
295         release_mem_region(port->mapbase, 0x100);
296 }
297 
298 static int apbuart_request_port(struct uart_port *port)
299 {
300         return request_mem_region(port->mapbase, 0x100, "grlib-apbuart")
301             != NULL ? 0 : -EBUSY;
302         return 0;
303 }
304 
305 /* Configure/autoconfigure the port */
306 static void apbuart_config_port(struct uart_port *port, int flags)
307 {
308         if (flags & UART_CONFIG_TYPE) {
309                 port->type = PORT_APBUART;
310                 apbuart_request_port(port);
311         }
312 }
313 
314 /* Verify the new serial_struct (for TIOCSSERIAL) */
315 static int apbuart_verify_port(struct uart_port *port,
316                                struct serial_struct *ser)
317 {
318         int ret = 0;
319         if (ser->type != PORT_UNKNOWN && ser->type != PORT_APBUART)
320                 ret = -EINVAL;
321         if (ser->irq < 0 || ser->irq >= NR_IRQS)
322                 ret = -EINVAL;
323         if (ser->baud_base < 9600)
324                 ret = -EINVAL;
325         return ret;
326 }
327 
328 static struct uart_ops grlib_apbuart_ops = {
329         .tx_empty = apbuart_tx_empty,
330         .set_mctrl = apbuart_set_mctrl,
331         .get_mctrl = apbuart_get_mctrl,
332         .stop_tx = apbuart_stop_tx,
333         .start_tx = apbuart_start_tx,
334         .stop_rx = apbuart_stop_rx,
335         .break_ctl = apbuart_break_ctl,
336         .startup = apbuart_startup,
337         .shutdown = apbuart_shutdown,
338         .set_termios = apbuart_set_termios,
339         .type = apbuart_type,
340         .release_port = apbuart_release_port,
341         .request_port = apbuart_request_port,
342         .config_port = apbuart_config_port,
343         .verify_port = apbuart_verify_port,
344 };
345 
346 static struct uart_port grlib_apbuart_ports[UART_NR];
347 static struct device_node *grlib_apbuart_nodes[UART_NR];
348 
349 static int apbuart_scan_fifo_size(struct uart_port *port, int portnumber)
350 {
351         int ctrl, loop = 0;
352         int status;
353         int fifosize;
354         unsigned long flags;
355 
356         ctrl = UART_GET_CTRL(port);
357 
358         /*
359          * Enable the transceiver and wait for it to be ready to send data.
360          * Clear interrupts so that this process will not be externally
361          * interrupted in the middle (which can cause the transceiver to
362          * drain prematurely).
363          */
364 
365         local_irq_save(flags);
366 
367         UART_PUT_CTRL(port, ctrl | UART_CTRL_TE);
368 
369         while (!UART_TX_READY(UART_GET_STATUS(port)))
370                 loop++;
371 
372         /*
373          * Disable the transceiver so data isn't actually sent during the
374          * actual test.
375          */
376 
377         UART_PUT_CTRL(port, ctrl & ~(UART_CTRL_TE));
378 
379         fifosize = 1;
380         UART_PUT_CHAR(port, 0);
381 
382         /*
383          * So long as transmitting a character increments the tranceivier FIFO
384          * length the FIFO must be at least that big. These bytes will
385          * automatically drain off of the FIFO.
386          */
387 
388         status = UART_GET_STATUS(port);
389         while (((status >> 20) & 0x3F) == fifosize) {
390                 fifosize++;
391                 UART_PUT_CHAR(port, 0);
392                 status = UART_GET_STATUS(port);
393         }
394 
395         fifosize--;
396 
397         UART_PUT_CTRL(port, ctrl);
398         local_irq_restore(flags);
399 
400         if (fifosize == 0)
401                 fifosize = 1;
402 
403         return fifosize;
404 }
405 
406 static void apbuart_flush_fifo(struct uart_port *port)
407 {
408         int i;
409 
410         for (i = 0; i < port->fifosize; i++)
411                 UART_GET_CHAR(port);
412 }
413 
414 
415 /* ======================================================================== */
416 /* Console driver, if enabled                                               */
417 /* ======================================================================== */
418 
419 #ifdef CONFIG_SERIAL_GRLIB_GAISLER_APBUART_CONSOLE
420 
421 static void apbuart_console_putchar(struct uart_port *port, int ch)
422 {
423         unsigned int status;
424         do {
425                 status = UART_GET_STATUS(port);
426         } while (!UART_TX_READY(status));
427         UART_PUT_CHAR(port, ch);
428 }
429 
430 static void
431 apbuart_console_write(struct console *co, const char *s, unsigned int count)
432 {
433         struct uart_port *port = &grlib_apbuart_ports[co->index];
434         unsigned int status, old_cr, new_cr;
435 
436         /* First save the CR then disable the interrupts */
437         old_cr = UART_GET_CTRL(port);
438         new_cr = old_cr & ~(UART_CTRL_RI | UART_CTRL_TI);
439         UART_PUT_CTRL(port, new_cr);
440 
441         uart_console_write(port, s, count, apbuart_console_putchar);
442 
443         /*
444          *      Finally, wait for transmitter to become empty
445          *      and restore the TCR
446          */
447         do {
448                 status = UART_GET_STATUS(port);
449         } while (!UART_TX_READY(status));
450         UART_PUT_CTRL(port, old_cr);
451 }
452 
453 static void __init
454 apbuart_console_get_options(struct uart_port *port, int *baud,
455                             int *parity, int *bits)
456 {
457         if (UART_GET_CTRL(port) & (UART_CTRL_RE | UART_CTRL_TE)) {
458 
459                 unsigned int quot, status;
460                 status = UART_GET_STATUS(port);
461 
462                 *parity = 'n';
463                 if (status & UART_CTRL_PE) {
464                         if ((status & UART_CTRL_PS) == 0)
465                                 *parity = 'e';
466                         else
467                                 *parity = 'o';
468                 }
469 
470                 *bits = 8;
471                 quot = UART_GET_SCAL(port) / 8;
472                 *baud = port->uartclk / (16 * (quot + 1));
473         }
474 }
475 
476 static int __init apbuart_console_setup(struct console *co, char *options)
477 {
478         struct uart_port *port;
479         int baud = 38400;
480         int bits = 8;
481         int parity = 'n';
482         int flow = 'n';
483 
484         pr_debug("apbuart_console_setup co=%p, co->index=%i, options=%s\n",
485                  co, co->index, options);
486 
487         /*
488          * Check whether an invalid uart number has been specified, and
489          * if so, search for the first available port that does have
490          * console support.
491          */
492         if (co->index >= grlib_apbuart_port_nr)
493                 co->index = 0;
494 
495         port = &grlib_apbuart_ports[co->index];
496 
497         spin_lock_init(&port->lock);
498 
499         if (options)
500                 uart_parse_options(options, &baud, &parity, &bits, &flow);
501         else
502                 apbuart_console_get_options(port, &baud, &parity, &bits);
503 
504         return uart_set_options(port, co, baud, parity, bits, flow);
505 }
506 
507 static struct uart_driver grlib_apbuart_driver;
508 
509 static struct console grlib_apbuart_console = {
510         .name = "ttyS",
511         .write = apbuart_console_write,
512         .device = uart_console_device,
513         .setup = apbuart_console_setup,
514         .flags = CON_PRINTBUFFER,
515         .index = -1,
516         .data = &grlib_apbuart_driver,
517 };
518 
519 
520 static int grlib_apbuart_configure(void);
521 
522 static int __init apbuart_console_init(void)
523 {
524         if (grlib_apbuart_configure())
525                 return -ENODEV;
526         register_console(&grlib_apbuart_console);
527         return 0;
528 }
529 
530 console_initcall(apbuart_console_init);
531 
532 #define APBUART_CONSOLE (&grlib_apbuart_console)
533 #else
534 #define APBUART_CONSOLE NULL
535 #endif
536 
537 static struct uart_driver grlib_apbuart_driver = {
538         .owner = THIS_MODULE,
539         .driver_name = "serial",
540         .dev_name = "ttyS",
541         .major = SERIAL_APBUART_MAJOR,
542         .minor = SERIAL_APBUART_MINOR,
543         .nr = UART_NR,
544         .cons = APBUART_CONSOLE,
545 };
546 
547 
548 /* ======================================================================== */
549 /* OF Platform Driver                                                       */
550 /* ======================================================================== */
551 
552 static int apbuart_probe(struct platform_device *op)
553 {
554         int i;
555         struct uart_port *port = NULL;
556 
557         for (i = 0; i < grlib_apbuart_port_nr; i++) {
558                 if (op->dev.of_node == grlib_apbuart_nodes[i])
559                         break;
560         }
561 
562         port = &grlib_apbuart_ports[i];
563         port->dev = &op->dev;
564         port->irq = op->archdata.irqs[0];
565 
566         uart_add_one_port(&grlib_apbuart_driver, (struct uart_port *) port);
567 
568         apbuart_flush_fifo((struct uart_port *) port);
569 
570         printk(KERN_INFO "grlib-apbuart at 0x%llx, irq %d\n",
571                (unsigned long long) port->mapbase, port->irq);
572         return 0;
573 }
574 
575 static struct of_device_id apbuart_match[] = {
576         {
577          .name = "GAISLER_APBUART",
578          },
579         {
580          .name = "01_00c",
581          },
582         {},
583 };
584 
585 static struct platform_driver grlib_apbuart_of_driver = {
586         .probe = apbuart_probe,
587         .driver = {
588                 .owner = THIS_MODULE,
589                 .name = "grlib-apbuart",
590                 .of_match_table = apbuart_match,
591         },
592 };
593 
594 
595 static int __init grlib_apbuart_configure(void)
596 {
597         struct device_node *np;
598         int line = 0;
599 
600         for_each_matching_node(np, apbuart_match) {
601                 const int *ampopts;
602                 const u32 *freq_hz;
603                 const struct amba_prom_registers *regs;
604                 struct uart_port *port;
605                 unsigned long addr;
606 
607                 ampopts = of_get_property(np, "ampopts", NULL);
608                 if (ampopts && (*ampopts == 0))
609                         continue; /* Ignore if used by another OS instance */
610                 regs = of_get_property(np, "reg", NULL);
611                 /* Frequency of APB Bus is frequency of UART */
612                 freq_hz = of_get_property(np, "freq", NULL);
613 
614                 if (!regs || !freq_hz || (*freq_hz == 0))
615                         continue;
616 
617                 grlib_apbuart_nodes[line] = np;
618 
619                 addr = regs->phys_addr;
620 
621                 port = &grlib_apbuart_ports[line];
622 
623                 port->mapbase = addr;
624                 port->membase = ioremap(addr, sizeof(struct grlib_apbuart_regs_map));
625                 port->irq = 0;
626                 port->iotype = UPIO_MEM;
627                 port->ops = &grlib_apbuart_ops;
628                 port->flags = UPF_BOOT_AUTOCONF;
629                 port->line = line;
630                 port->uartclk = *freq_hz;
631                 port->fifosize = apbuart_scan_fifo_size((struct uart_port *) port, line);
632                 line++;
633 
634                 /* We support maximum UART_NR uarts ... */
635                 if (line == UART_NR)
636                         break;
637         }
638 
639         grlib_apbuart_driver.nr = grlib_apbuart_port_nr = line;
640         return line ? 0 : -ENODEV;
641 }
642 
643 static int __init grlib_apbuart_init(void)
644 {
645         int ret;
646 
647         /* Find all APBUARTS in device the tree and initialize their ports */
648         ret = grlib_apbuart_configure();
649         if (ret)
650                 return ret;
651 
652         printk(KERN_INFO "Serial: GRLIB APBUART driver\n");
653 
654         ret = uart_register_driver(&grlib_apbuart_driver);
655 
656         if (ret) {
657                 printk(KERN_ERR "%s: uart_register_driver failed (%i)\n",
658                        __FILE__, ret);
659                 return ret;
660         }
661 
662         ret = platform_driver_register(&grlib_apbuart_of_driver);
663         if (ret) {
664                 printk(KERN_ERR
665                        "%s: platform_driver_register failed (%i)\n",
666                        __FILE__, ret);
667                 uart_unregister_driver(&grlib_apbuart_driver);
668                 return ret;
669         }
670 
671         return ret;
672 }
673 
674 static void __exit grlib_apbuart_exit(void)
675 {
676         int i;
677 
678         for (i = 0; i < grlib_apbuart_port_nr; i++)
679                 uart_remove_one_port(&grlib_apbuart_driver,
680                                      &grlib_apbuart_ports[i]);
681 
682         uart_unregister_driver(&grlib_apbuart_driver);
683         platform_driver_unregister(&grlib_apbuart_of_driver);
684 }
685 
686 module_init(grlib_apbuart_init);
687 module_exit(grlib_apbuart_exit);
688 
689 MODULE_AUTHOR("Aeroflex Gaisler AB");
690 MODULE_DESCRIPTION("GRLIB APBUART serial driver");
691 MODULE_VERSION("2.1");
692 MODULE_LICENSE("GPL");
693 

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