1 /*
2 * drivers/serial/v850e_uart.c -- Serial I/O using V850E on-chip UART or UARTB
3 *
4 * Copyright (C) 2001,02,03 NEC Electronics Corporation
5 * Copyright (C) 2001,02,03 Miles Bader <miles@gnu.org>
6 *
7 * This file is subject to the terms and conditions of the GNU General
8 * Public License. See the file COPYING in the main directory of this
9 * archive for more details.
10 *
11 * Written by Miles Bader <miles@gnu.org>
12 */
13
14 /* This driver supports both the original V850E UART interface (called
15 merely `UART' in the docs) and the newer `UARTB' interface, which is
16 roughly a superset of the first one. The selection is made at
17 configure time -- if CONFIG_V850E_UARTB is defined, then UARTB is
18 presumed, otherwise the old UART -- as these are on-CPU UARTS, a system
19 can never have both.
20
21 The UARTB interface also has a 16-entry FIFO mode, which is not
22 yet supported by this driver. */
23
24 #include <linux/kernel.h>
25 #include <linux/init.h>
26 #include <linux/module.h>
27 #include <linux/console.h>
28 #include <linux/tty.h>
29 #include <linux/tty_flip.h>
30 #include <linux/serial.h>
31 #include <linux/serial_core.h>
32
33 #include <asm/v850e_uart.h>
34
35 /* Initial UART state. This may be overridden by machine-dependent headers. */
36 #ifndef V850E_UART_INIT_BAUD
37 #define V850E_UART_INIT_BAUD 115200
38 #endif
39 #ifndef V850E_UART_INIT_CFLAGS
40 #define V850E_UART_INIT_CFLAGS (B115200 | CS8 | CREAD)
41 #endif
42
43 /* A string used for prefixing printed descriptions; since the same UART
44 macro is actually used on other chips than the V850E. This must be a
45 constant string. */
46 #ifndef V850E_UART_CHIP_NAME
47 #define V850E_UART_CHIP_NAME "V850E"
48 #endif
49
50 #define V850E_UART_MINOR_BASE 64 /* First tty minor number */
51
52
53 /* Low-level UART functions. */
54
55 /* Configure and turn on uart channel CHAN, using the termios `control
56 modes' bits in CFLAGS, and a baud-rate of BAUD. */
57 void v850e_uart_configure (unsigned chan, unsigned cflags, unsigned baud)
58 {
59 int flags;
60 v850e_uart_speed_t old_speed;
61 v850e_uart_config_t old_config;
62 v850e_uart_speed_t new_speed = v850e_uart_calc_speed (baud);
63 v850e_uart_config_t new_config = v850e_uart_calc_config (cflags);
64
65 /* Disable interrupts while we're twiddling the hardware. */
66 local_irq_save (flags);
67
68 #ifdef V850E_UART_PRE_CONFIGURE
69 V850E_UART_PRE_CONFIGURE (chan, cflags, baud);
70 #endif
71
72 old_config = V850E_UART_CONFIG (chan);
73 old_speed = v850e_uart_speed (chan);
74
75 if (! v850e_uart_speed_eq (old_speed, new_speed)) {
76 /* The baud rate has changed. First, disable the UART. */
77 V850E_UART_CONFIG (chan) = V850E_UART_CONFIG_FINI;
78 old_config = 0; /* Force the uart to be re-initialized. */
79
80 /* Reprogram the baud-rate generator. */
81 v850e_uart_set_speed (chan, new_speed);
82 }
83
84 if (! (old_config & V850E_UART_CONFIG_ENABLED)) {
85 /* If we are using the uart for the first time, start by
86 enabling it, which must be done before turning on any
87 other bits. */
88 V850E_UART_CONFIG (chan) = V850E_UART_CONFIG_INIT;
89 /* See the initial state. */
90 old_config = V850E_UART_CONFIG (chan);
91 }
92
93 if (new_config != old_config) {
94 /* Which of the TXE/RXE bits we'll temporarily turn off
95 before changing other control bits. */
96 unsigned temp_disable = 0;
97 /* Which of the TXE/RXE bits will be enabled. */
98 unsigned enable = 0;
99 unsigned changed_bits = new_config ^ old_config;
100
101 /* Which of RX/TX will be enabled in the new configuration. */
102 if (new_config & V850E_UART_CONFIG_RX_BITS)
103 enable |= (new_config & V850E_UART_CONFIG_RX_ENABLE);
104 if (new_config & V850E_UART_CONFIG_TX_BITS)
105 enable |= (new_config & V850E_UART_CONFIG_TX_ENABLE);
106
107 /* Figure out which of RX/TX needs to be disabled; note
108 that this will only happen if they're not already
109 disabled. */
110 if (changed_bits & V850E_UART_CONFIG_RX_BITS)
111 temp_disable
112 |= (old_config & V850E_UART_CONFIG_RX_ENABLE);
113 if (changed_bits & V850E_UART_CONFIG_TX_BITS)
114 temp_disable
115 |= (old_config & V850E_UART_CONFIG_TX_ENABLE);
116
117 /* We have to turn off RX and/or TX mode before changing
118 any associated control bits. */
119 if (temp_disable)
120 V850E_UART_CONFIG (chan) = old_config & ~temp_disable;
121
122 /* Write the new control bits, while RX/TX are disabled. */
123 if (changed_bits & ~enable)
124 V850E_UART_CONFIG (chan) = new_config & ~enable;
125
126 v850e_uart_config_delay (new_config, new_speed);
127
128 /* Write the final version, with enable bits turned on. */
129 V850E_UART_CONFIG (chan) = new_config;
130 }
131
132 local_irq_restore (flags);
133 }
134
135
136 /* Low-level console. */
137
138 #ifdef CONFIG_V850E_UART_CONSOLE
139
140 static void v850e_uart_cons_write (struct console *co,
141 const char *s, unsigned count)
142 {
143 if (count > 0) {
144 unsigned chan = co->index;
145 unsigned irq = V850E_UART_TX_IRQ (chan);
146 int irq_was_enabled, irq_was_pending, flags;
147
148 /* We don't want to get `transmission completed'
149 interrupts, since we're busy-waiting, so we disable them
150 while sending (we don't disable interrupts entirely
151 because sending over a serial line is really slow). We
152 save the status of the tx interrupt and restore it when
153 we're done so that using printk doesn't interfere with
154 normal serial transmission (other than interleaving the
155 output, of course!). This should work correctly even if
156 this function is interrupted and the interrupt printks
157 something. */
158
159 /* Disable interrupts while fiddling with tx interrupt. */
160 local_irq_save (flags);
161 /* Get current tx interrupt status. */
162 irq_was_enabled = v850e_intc_irq_enabled (irq);
163 irq_was_pending = v850e_intc_irq_pending (irq);
164 /* Disable tx interrupt if necessary. */
165 if (irq_was_enabled)
166 v850e_intc_disable_irq (irq);
167 /* Turn interrupts back on. */
168 local_irq_restore (flags);
169
170 /* Send characters. */
171 while (count > 0) {
172 int ch = *s++;
173
174 if (ch == '\n') {
175 /* We don't have the benefit of a tty
176 driver, so translate NL into CR LF. */
177 v850e_uart_wait_for_xmit_ok (chan);
178 v850e_uart_putc (chan, '\r');
179 }
180
181 v850e_uart_wait_for_xmit_ok (chan);
182 v850e_uart_putc (chan, ch);
183
184 count--;
185 }
186
187 /* Restore saved tx interrupt status. */
188 if (irq_was_enabled) {
189 /* Wait for the last character we sent to be
190 completely transmitted (as we'll get an
191 interrupt interrupt at that point). */
192 v850e_uart_wait_for_xmit_done (chan);
193 /* Clear pending interrupts received due
194 to our transmission, unless there was already
195 one pending, in which case we want the
196 handler to be called. */
197 if (! irq_was_pending)
198 v850e_intc_clear_pending_irq (irq);
199 /* ... and then turn back on handling. */
200 v850e_intc_enable_irq (irq);
201 }
202 }
203 }
204
205 extern struct uart_driver v850e_uart_driver;
206 static struct console v850e_uart_cons =
207 {
208 .name = "ttyS",
209 .write = v850e_uart_cons_write,
210 .device = uart_console_device,
211 .flags = CON_PRINTBUFFER,
212 .cflag = V850E_UART_INIT_CFLAGS,
213 .index = -1,
214 .data = &v850e_uart_driver,
215 };
216
217 void v850e_uart_cons_init (unsigned chan)
218 {
219 v850e_uart_configure (chan, V850E_UART_INIT_CFLAGS,
220 V850E_UART_INIT_BAUD);
221 v850e_uart_cons.index = chan;
222 register_console (&v850e_uart_cons);
223 printk ("Console: %s on-chip UART channel %d\n",
224 V850E_UART_CHIP_NAME, chan);
225 }
226
227 /* This is what the init code actually calls. */
228 static int v850e_uart_console_init (void)
229 {
230 v850e_uart_cons_init (V850E_UART_CONSOLE_CHANNEL);
231 return 0;
232 }
233 console_initcall(v850e_uart_console_init);
234
235 #define V850E_UART_CONSOLE &v850e_uart_cons
236
237 #else /* !CONFIG_V850E_UART_CONSOLE */
238 #define V850E_UART_CONSOLE 0
239 #endif /* CONFIG_V850E_UART_CONSOLE */
240
241 /* TX/RX interrupt handlers. */
242
243 static void v850e_uart_stop_tx (struct uart_port *port, unsigned tty_stop);
244
245 void v850e_uart_tx (struct uart_port *port)
246 {
247 struct circ_buf *xmit = &port->info->xmit;
248 int stopped = uart_tx_stopped (port);
249
250 if (v850e_uart_xmit_ok (port->line)) {
251 int tx_ch;
252
253 if (port->x_char) {
254 tx_ch = port->x_char;
255 port->x_char = 0;
256 } else if (!uart_circ_empty (xmit) && !stopped) {
257 tx_ch = xmit->buf[xmit->tail];
258 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
259 } else
260 goto no_xmit;
261
262 v850e_uart_putc (port->line, tx_ch);
263 port->icount.tx++;
264
265 if (uart_circ_chars_pending (xmit) < WAKEUP_CHARS)
266 uart_write_wakeup (port);
267 }
268
269 no_xmit:
270 if (uart_circ_empty (xmit) || stopped)
271 v850e_uart_stop_tx (port, stopped);
272 }
273
274 static irqreturn_t v850e_uart_tx_irq(int irq, void *data, struct pt_regs *regs)
275 {
276 struct uart_port *port = data;
277 v850e_uart_tx (port);
278 return IRQ_HANDLED;
279 }
280
281 static irqreturn_t v850e_uart_rx_irq(int irq, void *data, struct pt_regs *regs)
282 {
283 struct uart_port *port = data;
284 unsigned ch_stat = TTY_NORMAL;
285 unsigned ch = v850e_uart_getc (port->line);
286 unsigned err = v850e_uart_err (port->line);
287
288 if (err) {
289 if (err & V850E_UART_ERR_OVERRUN) {
290 ch_stat = TTY_OVERRUN;
291 port->icount.overrun++;
292 } else if (err & V850E_UART_ERR_FRAME) {
293 ch_stat = TTY_FRAME;
294 port->icount.frame++;
295 } else if (err & V850E_UART_ERR_PARITY) {
296 ch_stat = TTY_PARITY;
297 port->icount.parity++;
298 }
299 }
300
301 port->icount.rx++;
302
303 tty_insert_flip_char (port->info->tty, ch, ch_stat);
304 tty_schedule_flip (port->info->tty);
305
306 return IRQ_HANDLED;
307 }
308
309
310 /* Control functions for the serial framework. */
311
312 static void v850e_uart_nop (struct uart_port *port) { }
313 static int v850e_uart_success (struct uart_port *port) { return 0; }
314
315 static unsigned v850e_uart_tx_empty (struct uart_port *port)
316 {
317 return TIOCSER_TEMT; /* Can't detect. */
318 }
319
320 static void v850e_uart_set_mctrl (struct uart_port *port, unsigned mctrl)
321 {
322 #ifdef V850E_UART_SET_RTS
323 V850E_UART_SET_RTS (port->line, (mctrl & TIOCM_RTS));
324 #endif
325 }
326
327 static unsigned v850e_uart_get_mctrl (struct uart_port *port)
328 {
329 /* We don't support DCD or DSR, so consider them permanently active. */
330 int mctrl = TIOCM_CAR | TIOCM_DSR;
331
332 /* We may support CTS. */
333 #ifdef V850E_UART_CTS
334 mctrl |= V850E_UART_CTS(port->line) ? TIOCM_CTS : 0;
335 #else
336 mctrl |= TIOCM_CTS;
337 #endif
338
339 return mctrl;
340 }
341
342 static void v850e_uart_start_tx (struct uart_port *port, unsigned tty_start)
343 {
344 v850e_intc_disable_irq (V850E_UART_TX_IRQ (port->line));
345 v850e_uart_tx (port);
346 v850e_intc_enable_irq (V850E_UART_TX_IRQ (port->line));
347 }
348
349 static void v850e_uart_stop_tx (struct uart_port *port, unsigned tty_stop)
350 {
351 v850e_intc_disable_irq (V850E_UART_TX_IRQ (port->line));
352 }
353
354 static void v850e_uart_start_rx (struct uart_port *port)
355 {
356 v850e_intc_enable_irq (V850E_UART_RX_IRQ (port->line));
357 }
358
359 static void v850e_uart_stop_rx (struct uart_port *port)
360 {
361 v850e_intc_disable_irq (V850E_UART_RX_IRQ (port->line));
362 }
363
364 static void v850e_uart_break_ctl (struct uart_port *port, int break_ctl)
365 {
366 /* Umm, do this later. */
367 }
368
369 static int v850e_uart_startup (struct uart_port *port)
370 {
371 int err;
372
373 /* Alloc RX irq. */
374 err = request_irq (V850E_UART_RX_IRQ (port->line), v850e_uart_rx_irq,
375 SA_INTERRUPT, "v850e_uart", port);
376 if (err)
377 return err;
378
379 /* Alloc TX irq. */
380 err = request_irq (V850E_UART_TX_IRQ (port->line), v850e_uart_tx_irq,
381 SA_INTERRUPT, "v850e_uart", port);
382 if (err) {
383 free_irq (V850E_UART_RX_IRQ (port->line), port);
384 return err;
385 }
386
387 v850e_uart_start_rx (port);
388
389 return 0;
390 }
391
392 static void v850e_uart_shutdown (struct uart_port *port)
393 {
394 /* Disable port interrupts. */
395 free_irq (V850E_UART_TX_IRQ (port->line), port);
396 free_irq (V850E_UART_RX_IRQ (port->line), port);
397
398 /* Turn off xmit/recv enable bits. */
399 V850E_UART_CONFIG (port->line)
400 &= ~(V850E_UART_CONFIG_TX_ENABLE
401 | V850E_UART_CONFIG_RX_ENABLE);
402 /* Then reset the channel. */
403 V850E_UART_CONFIG (port->line) = 0;
404 }
405
406 static void
407 v850e_uart_set_termios (struct uart_port *port, struct termios *termios,
408 struct termios *old)
409 {
410 unsigned cflags = termios->c_cflag;
411
412 /* Restrict flags to legal values. */
413 if ((cflags & CSIZE) != CS7 && (cflags & CSIZE) != CS8)
414 /* The new value of CSIZE is invalid, use the old value. */
415 cflags = (cflags & ~CSIZE)
416 | (old ? (old->c_cflag & CSIZE) : CS8);
417
418 termios->c_cflag = cflags;
419
420 v850e_uart_configure (port->line, cflags,
421 uart_get_baud_rate (port, termios, old,
422 v850e_uart_min_baud(),
423 v850e_uart_max_baud()));
424 }
425
426 static const char *v850e_uart_type (struct uart_port *port)
427 {
428 return port->type == PORT_V850E_UART ? "v850e_uart" : 0;
429 }
430
431 static void v850e_uart_config_port (struct uart_port *port, int flags)
432 {
433 if (flags & UART_CONFIG_TYPE)
434 port->type = PORT_V850E_UART;
435 }
436
437 static int
438 v850e_uart_verify_port (struct uart_port *port, struct serial_struct *ser)
439 {
440 if (ser->type != PORT_UNKNOWN && ser->type != PORT_V850E_UART)
441 return -EINVAL;
442 if (ser->irq != V850E_UART_TX_IRQ (port->line))
443 return -EINVAL;
444 return 0;
445 }
446
447 static struct uart_ops v850e_uart_ops = {
448 .tx_empty = v850e_uart_tx_empty,
449 .get_mctrl = v850e_uart_get_mctrl,
450 .set_mctrl = v850e_uart_set_mctrl,
451 .start_tx = v850e_uart_start_tx,
452 .stop_tx = v850e_uart_stop_tx,
453 .stop_rx = v850e_uart_stop_rx,
454 .enable_ms = v850e_uart_nop,
455 .break_ctl = v850e_uart_break_ctl,
456 .startup = v850e_uart_startup,
457 .shutdown = v850e_uart_shutdown,
458 .set_termios = v850e_uart_set_termios,
459 .type = v850e_uart_type,
460 .release_port = v850e_uart_nop,
461 .request_port = v850e_uart_success,
462 .config_port = v850e_uart_config_port,
463 .verify_port = v850e_uart_verify_port,
464 };
465
466 /* Initialization and cleanup. */
467
468 static struct uart_driver v850e_uart_driver = {
469 .owner = THIS_MODULE,
470 .driver_name = "v850e_uart",
471 .devfs_name = "tts/",
472 .dev_name = "ttyS",
473 .major = TTY_MAJOR,
474 .minor = V850E_UART_MINOR_BASE,
475 .nr = V850E_UART_NUM_CHANNELS,
476 .cons = V850E_UART_CONSOLE,
477 };
478
479
480 static struct uart_port v850e_uart_ports[V850E_UART_NUM_CHANNELS];
481
482 static int __init v850e_uart_init (void)
483 {
484 int rval;
485
486 printk (KERN_INFO "%s on-chip UART\n", V850E_UART_CHIP_NAME);
487
488 rval = uart_register_driver (&v850e_uart_driver);
489 if (rval == 0) {
490 unsigned chan;
491
492 for (chan = 0; chan < V850E_UART_NUM_CHANNELS; chan++) {
493 struct uart_port *port = &v850e_uart_ports[chan];
494
495 memset (port, 0, sizeof *port);
496
497 port->ops = &v850e_uart_ops;
498 port->line = chan;
499 port->iotype = SERIAL_IO_MEM;
500 port->flags = UPF_BOOT_AUTOCONF;
501
502 /* We actually use multiple IRQs, but the serial
503 framework seems to mainly use this for
504 informational purposes anyway. Here we use the TX
505 irq. */
506 port->irq = V850E_UART_TX_IRQ (chan);
507
508 /* The serial framework doesn't really use these
509 membase/mapbase fields for anything useful, but
510 it requires that they be something non-zero to
511 consider the port `valid', and also uses them
512 for informational purposes. */
513 port->membase = (void *)V850E_UART_BASE_ADDR (chan);
514 port->mapbase = V850E_UART_BASE_ADDR (chan);
515
516 /* The framework insists on knowing the uart's master
517 clock freq, though it doesn't seem to do anything
518 useful for us with it. We must make it at least
519 higher than (the maximum baud rate * 16), otherwise
520 the framework will puke during its internal
521 calculations, and force the baud rate to be 9600.
522 To be accurate though, just repeat the calculation
523 we use when actually setting the speed. */
524 port->uartclk = v850e_uart_max_clock() * 16;
525
526 uart_add_one_port (&v850e_uart_driver, port);
527 }
528 }
529
530 return rval;
531 }
532
533 static void __exit v850e_uart_exit (void)
534 {
535 unsigned chan;
536
537 for (chan = 0; chan < V850E_UART_NUM_CHANNELS; chan++)
538 uart_remove_one_port (&v850e_uart_driver,
539 &v850e_uart_ports[chan]);
540
541 uart_unregister_driver (&v850e_uart_driver);
542 }
543
544 module_init (v850e_uart_init);
545 module_exit (v850e_uart_exit);
546
547 MODULE_AUTHOR ("Miles Bader");
548 MODULE_DESCRIPTION ("NEC " V850E_UART_CHIP_NAME " on-chip UART");
549 MODULE_LICENSE ("GPL");
550
|
This page was automatically generated by the
LXR engine.
|