1 /*
2 * linux/drivers/serial/21285.c
3 *
4 * Driver for the serial port on the 21285 StrongArm-110 core logic chip.
5 *
6 * Based on drivers/char/serial.c
7 *
8 * $Id: 21285.c,v 1.37 2002/07/28 10:03:27 rmk Exp $
9 */
10 #include <linux/module.h>
11 #include <linux/tty.h>
12 #include <linux/ioport.h>
13 #include <linux/init.h>
14 #include <linux/console.h>
15 #include <linux/device.h>
16 #include <linux/tty_flip.h>
17 #include <linux/serial_core.h>
18 #include <linux/serial.h>
19
20 #include <asm/io.h>
21 #include <asm/irq.h>
22 #include <asm/mach-types.h>
23 #include <asm/hardware/dec21285.h>
24 #include <asm/hardware.h>
25
26 #define BAUD_BASE (mem_fclk_21285/64)
27
28 #define SERIAL_21285_NAME "ttyFB"
29 #define SERIAL_21285_MAJOR 204
30 #define SERIAL_21285_MINOR 4
31
32 #define RXSTAT_DUMMY_READ 0x80000000
33 #define RXSTAT_FRAME (1 << 0)
34 #define RXSTAT_PARITY (1 << 1)
35 #define RXSTAT_OVERRUN (1 << 2)
36 #define RXSTAT_ANYERR (RXSTAT_FRAME|RXSTAT_PARITY|RXSTAT_OVERRUN)
37
38 #define H_UBRLCR_BREAK (1 << 0)
39 #define H_UBRLCR_PARENB (1 << 1)
40 #define H_UBRLCR_PAREVN (1 << 2)
41 #define H_UBRLCR_STOPB (1 << 3)
42 #define H_UBRLCR_FIFO (1 << 4)
43
44 static const char serial21285_name[] = "Footbridge UART";
45
46 #define tx_enabled(port) ((port)->unused[0])
47 #define rx_enabled(port) ((port)->unused[1])
48
49 /*
50 * The documented expression for selecting the divisor is:
51 * BAUD_BASE / baud - 1
52 * However, typically BAUD_BASE is not divisible by baud, so
53 * we want to select the divisor that gives us the minimum
54 * error. Therefore, we want:
55 * int(BAUD_BASE / baud - 0.5) ->
56 * int(BAUD_BASE / baud - (baud >> 1) / baud) ->
57 * int((BAUD_BASE - (baud >> 1)) / baud)
58 */
59
60 static void serial21285_stop_tx(struct uart_port *port)
61 {
62 if (tx_enabled(port)) {
63 disable_irq(IRQ_CONTX);
64 tx_enabled(port) = 0;
65 }
66 }
67
68 static void serial21285_start_tx(struct uart_port *port)
69 {
70 if (!tx_enabled(port)) {
71 enable_irq(IRQ_CONTX);
72 tx_enabled(port) = 1;
73 }
74 }
75
76 static void serial21285_stop_rx(struct uart_port *port)
77 {
78 if (rx_enabled(port)) {
79 disable_irq(IRQ_CONRX);
80 rx_enabled(port) = 0;
81 }
82 }
83
84 static void serial21285_enable_ms(struct uart_port *port)
85 {
86 }
87
88 static irqreturn_t serial21285_rx_chars(int irq, void *dev_id)
89 {
90 struct uart_port *port = dev_id;
91 struct tty_struct *tty = port->info->tty;
92 unsigned int status, ch, flag, rxs, max_count = 256;
93
94 status = *CSR_UARTFLG;
95 while (!(status & 0x10) && max_count--) {
96 ch = *CSR_UARTDR;
97 flag = TTY_NORMAL;
98 port->icount.rx++;
99
100 rxs = *CSR_RXSTAT | RXSTAT_DUMMY_READ;
101 if (unlikely(rxs & RXSTAT_ANYERR)) {
102 if (rxs & RXSTAT_PARITY)
103 port->icount.parity++;
104 else if (rxs & RXSTAT_FRAME)
105 port->icount.frame++;
106 if (rxs & RXSTAT_OVERRUN)
107 port->icount.overrun++;
108
109 rxs &= port->read_status_mask;
110
111 if (rxs & RXSTAT_PARITY)
112 flag = TTY_PARITY;
113 else if (rxs & RXSTAT_FRAME)
114 flag = TTY_FRAME;
115 }
116
117 uart_insert_char(port, rxs, RXSTAT_OVERRUN, ch, flag);
118
119 status = *CSR_UARTFLG;
120 }
121 tty_flip_buffer_push(tty);
122
123 return IRQ_HANDLED;
124 }
125
126 static irqreturn_t serial21285_tx_chars(int irq, void *dev_id)
127 {
128 struct uart_port *port = dev_id;
129 struct circ_buf *xmit = &port->info->xmit;
130 int count = 256;
131
132 if (port->x_char) {
133 *CSR_UARTDR = port->x_char;
134 port->icount.tx++;
135 port->x_char = 0;
136 goto out;
137 }
138 if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
139 serial21285_stop_tx(port);
140 goto out;
141 }
142
143 do {
144 *CSR_UARTDR = xmit->buf[xmit->tail];
145 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
146 port->icount.tx++;
147 if (uart_circ_empty(xmit))
148 break;
149 } while (--count > 0 && !(*CSR_UARTFLG & 0x20));
150
151 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
152 uart_write_wakeup(port);
153
154 if (uart_circ_empty(xmit))
155 serial21285_stop_tx(port);
156
157 out:
158 return IRQ_HANDLED;
159 }
160
161 static unsigned int serial21285_tx_empty(struct uart_port *port)
162 {
163 return (*CSR_UARTFLG & 8) ? 0 : TIOCSER_TEMT;
164 }
165
166 /* no modem control lines */
167 static unsigned int serial21285_get_mctrl(struct uart_port *port)
168 {
169 return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
170 }
171
172 static void serial21285_set_mctrl(struct uart_port *port, unsigned int mctrl)
173 {
174 }
175
176 static void serial21285_break_ctl(struct uart_port *port, int break_state)
177 {
178 unsigned long flags;
179 unsigned int h_lcr;
180
181 spin_lock_irqsave(&port->lock, flags);
182 h_lcr = *CSR_H_UBRLCR;
183 if (break_state)
184 h_lcr |= H_UBRLCR_BREAK;
185 else
186 h_lcr &= ~H_UBRLCR_BREAK;
187 *CSR_H_UBRLCR = h_lcr;
188 spin_unlock_irqrestore(&port->lock, flags);
189 }
190
191 static int serial21285_startup(struct uart_port *port)
192 {
193 int ret;
194
195 tx_enabled(port) = 1;
196 rx_enabled(port) = 1;
197
198 ret = request_irq(IRQ_CONRX, serial21285_rx_chars, 0,
199 serial21285_name, port);
200 if (ret == 0) {
201 ret = request_irq(IRQ_CONTX, serial21285_tx_chars, 0,
202 serial21285_name, port);
203 if (ret)
204 free_irq(IRQ_CONRX, port);
205 }
206
207 return ret;
208 }
209
210 static void serial21285_shutdown(struct uart_port *port)
211 {
212 free_irq(IRQ_CONTX, port);
213 free_irq(IRQ_CONRX, port);
214 }
215
216 static void
217 serial21285_set_termios(struct uart_port *port, struct ktermios *termios,
218 struct ktermios *old)
219 {
220 unsigned long flags;
221 unsigned int baud, quot, h_lcr;
222
223 /*
224 * We don't support modem control lines.
225 */
226 termios->c_cflag &= ~(HUPCL | CRTSCTS | CMSPAR);
227 termios->c_cflag |= CLOCAL;
228
229 /*
230 * We don't support BREAK character recognition.
231 */
232 termios->c_iflag &= ~(IGNBRK | BRKINT);
233
234 /*
235 * Ask the core to calculate the divisor for us.
236 */
237 baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
238 quot = uart_get_divisor(port, baud);
239
240 if (port->info && port->info->tty) {
241 struct tty_struct *tty = port->info->tty;
242 unsigned int b = port->uartclk / (16 * quot);
243 tty_encode_baud_rate(tty, b, b);
244 }
245
246 switch (termios->c_cflag & CSIZE) {
247 case CS5:
248 h_lcr = 0x00;
249 break;
250 case CS6:
251 h_lcr = 0x20;
252 break;
253 case CS7:
254 h_lcr = 0x40;
255 break;
256 default: /* CS8 */
257 h_lcr = 0x60;
258 break;
259 }
260
261 if (termios->c_cflag & CSTOPB)
262 h_lcr |= H_UBRLCR_STOPB;
263 if (termios->c_cflag & PARENB) {
264 h_lcr |= H_UBRLCR_PARENB;
265 if (!(termios->c_cflag & PARODD))
266 h_lcr |= H_UBRLCR_PAREVN;
267 }
268
269 if (port->fifosize)
270 h_lcr |= H_UBRLCR_FIFO;
271
272 spin_lock_irqsave(&port->lock, flags);
273
274 /*
275 * Update the per-port timeout.
276 */
277 uart_update_timeout(port, termios->c_cflag, baud);
278
279 /*
280 * Which character status flags are we interested in?
281 */
282 port->read_status_mask = RXSTAT_OVERRUN;
283 if (termios->c_iflag & INPCK)
284 port->read_status_mask |= RXSTAT_FRAME | RXSTAT_PARITY;
285
286 /*
287 * Which character status flags should we ignore?
288 */
289 port->ignore_status_mask = 0;
290 if (termios->c_iflag & IGNPAR)
291 port->ignore_status_mask |= RXSTAT_FRAME | RXSTAT_PARITY;
292 if (termios->c_iflag & IGNBRK && termios->c_iflag & IGNPAR)
293 port->ignore_status_mask |= RXSTAT_OVERRUN;
294
295 /*
296 * Ignore all characters if CREAD is not set.
297 */
298 if ((termios->c_cflag & CREAD) == 0)
299 port->ignore_status_mask |= RXSTAT_DUMMY_READ;
300
301 quot -= 1;
302
303 *CSR_UARTCON = 0;
304 *CSR_L_UBRLCR = quot & 0xff;
305 *CSR_M_UBRLCR = (quot >> 8) & 0x0f;
306 *CSR_H_UBRLCR = h_lcr;
307 *CSR_UARTCON = 1;
308
309 spin_unlock_irqrestore(&port->lock, flags);
310 }
311
312 static const char *serial21285_type(struct uart_port *port)
313 {
314 return port->type == PORT_21285 ? "DC21285" : NULL;
315 }
316
317 static void serial21285_release_port(struct uart_port *port)
318 {
319 release_mem_region(port->mapbase, 32);
320 }
321
322 static int serial21285_request_port(struct uart_port *port)
323 {
324 return request_mem_region(port->mapbase, 32, serial21285_name)
325 != NULL ? 0 : -EBUSY;
326 }
327
328 static void serial21285_config_port(struct uart_port *port, int flags)
329 {
330 if (flags & UART_CONFIG_TYPE && serial21285_request_port(port) == 0)
331 port->type = PORT_21285;
332 }
333
334 /*
335 * verify the new serial_struct (for TIOCSSERIAL).
336 */
337 static int serial21285_verify_port(struct uart_port *port, struct serial_struct *ser)
338 {
339 int ret = 0;
340 if (ser->type != PORT_UNKNOWN && ser->type != PORT_21285)
341 ret = -EINVAL;
342 if (ser->irq != NO_IRQ)
343 ret = -EINVAL;
344 if (ser->baud_base != port->uartclk / 16)
345 ret = -EINVAL;
346 return ret;
347 }
348
349 static struct uart_ops serial21285_ops = {
350 .tx_empty = serial21285_tx_empty,
351 .get_mctrl = serial21285_get_mctrl,
352 .set_mctrl = serial21285_set_mctrl,
353 .stop_tx = serial21285_stop_tx,
354 .start_tx = serial21285_start_tx,
355 .stop_rx = serial21285_stop_rx,
356 .enable_ms = serial21285_enable_ms,
357 .break_ctl = serial21285_break_ctl,
358 .startup = serial21285_startup,
359 .shutdown = serial21285_shutdown,
360 .set_termios = serial21285_set_termios,
361 .type = serial21285_type,
362 .release_port = serial21285_release_port,
363 .request_port = serial21285_request_port,
364 .config_port = serial21285_config_port,
365 .verify_port = serial21285_verify_port,
366 };
367
368 static struct uart_port serial21285_port = {
369 .mapbase = 0x42000160,
370 .iotype = UPIO_MEM,
371 .irq = NO_IRQ,
372 .fifosize = 16,
373 .ops = &serial21285_ops,
374 .flags = UPF_BOOT_AUTOCONF,
375 };
376
377 static void serial21285_setup_ports(void)
378 {
379 serial21285_port.uartclk = mem_fclk_21285 / 4;
380 }
381
382 #ifdef CONFIG_SERIAL_21285_CONSOLE
383 static void serial21285_console_putchar(struct uart_port *port, int ch)
384 {
385 while (*CSR_UARTFLG & 0x20)
386 barrier();
387 *CSR_UARTDR = ch;
388 }
389
390 static void
391 serial21285_console_write(struct console *co, const char *s,
392 unsigned int count)
393 {
394 uart_console_write(&serial21285_port, s, count, serial21285_console_putchar);
395 }
396
397 static void __init
398 serial21285_get_options(struct uart_port *port, int *baud,
399 int *parity, int *bits)
400 {
401 if (*CSR_UARTCON == 1) {
402 unsigned int tmp;
403
404 tmp = *CSR_H_UBRLCR;
405 switch (tmp & 0x60) {
406 case 0x00:
407 *bits = 5;
408 break;
409 case 0x20:
410 *bits = 6;
411 break;
412 case 0x40:
413 *bits = 7;
414 break;
415 default:
416 case 0x60:
417 *bits = 8;
418 break;
419 }
420
421 if (tmp & H_UBRLCR_PARENB) {
422 *parity = 'o';
423 if (tmp & H_UBRLCR_PAREVN)
424 *parity = 'e';
425 }
426
427 tmp = *CSR_L_UBRLCR | (*CSR_M_UBRLCR << 8);
428
429 *baud = port->uartclk / (16 * (tmp + 1));
430 }
431 }
432
433 static int __init serial21285_console_setup(struct console *co, char *options)
434 {
435 struct uart_port *port = &serial21285_port;
436 int baud = 9600;
437 int bits = 8;
438 int parity = 'n';
439 int flow = 'n';
440
441 if (machine_is_personal_server())
442 baud = 57600;
443
444 /*
445 * Check whether an invalid uart number has been specified, and
446 * if so, search for the first available port that does have
447 * console support.
448 */
449 if (options)
450 uart_parse_options(options, &baud, &parity, &bits, &flow);
451 else
452 serial21285_get_options(port, &baud, &parity, &bits);
453
454 return uart_set_options(port, co, baud, parity, bits, flow);
455 }
456
457 static struct uart_driver serial21285_reg;
458
459 static struct console serial21285_console =
460 {
461 .name = SERIAL_21285_NAME,
462 .write = serial21285_console_write,
463 .device = uart_console_device,
464 .setup = serial21285_console_setup,
465 .flags = CON_PRINTBUFFER,
466 .index = -1,
467 .data = &serial21285_reg,
468 };
469
470 static int __init rs285_console_init(void)
471 {
472 serial21285_setup_ports();
473 register_console(&serial21285_console);
474 return 0;
475 }
476 console_initcall(rs285_console_init);
477
478 #define SERIAL_21285_CONSOLE &serial21285_console
479 #else
480 #define SERIAL_21285_CONSOLE NULL
481 #endif
482
483 static struct uart_driver serial21285_reg = {
484 .owner = THIS_MODULE,
485 .driver_name = "ttyFB",
486 .dev_name = "ttyFB",
487 .major = SERIAL_21285_MAJOR,
488 .minor = SERIAL_21285_MINOR,
489 .nr = 1,
490 .cons = SERIAL_21285_CONSOLE,
491 };
492
493 static int __init serial21285_init(void)
494 {
495 int ret;
496
497 printk(KERN_INFO "Serial: 21285 driver $Revision: 1.37 $\n");
498
499 serial21285_setup_ports();
500
501 ret = uart_register_driver(&serial21285_reg);
502 if (ret == 0)
503 uart_add_one_port(&serial21285_reg, &serial21285_port);
504
505 return ret;
506 }
507
508 static void __exit serial21285_exit(void)
509 {
510 uart_remove_one_port(&serial21285_reg, &serial21285_port);
511 uart_unregister_driver(&serial21285_reg);
512 }
513
514 module_init(serial21285_init);
515 module_exit(serial21285_exit);
516
517 MODULE_LICENSE("GPL");
518 MODULE_DESCRIPTION("Intel Footbridge (21285) serial driver $Revision: 1.37 $");
519 MODULE_ALIAS_CHARDEV(SERIAL_21285_MAJOR, SERIAL_21285_MINOR);
520
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