2 * linux/drivers/char/21285.c
4 * Driver for the serial port on the 21285 StrongArm-110 core logic chip.
6 * Based on drivers/char/serial.c
8 * $Id: 21285.c,v 1.37 2002/07/28 10:03:27 rmk Exp $
10 #include <linux/config.h>
11 #include <linux/module.h>
12 #include <linux/tty.h>
13 #include <linux/ioport.h>
14 #include <linux/init.h>
15 #include <linux/console.h>
16 #include <linux/serial_core.h>
17 #include <linux/serial.h>
18 #include <linux/device.h>
22 #include <asm/hardware/dec21285.h>
23 #include <asm/hardware.h>
25 #define BAUD_BASE (mem_fclk_21285/64)
27 #define SERIAL_21285_NAME "ttyFB"
28 #define SERIAL_21285_MAJOR 204
29 #define SERIAL_21285_MINOR 4
31 #define RXSTAT_DUMMY_READ 0x80000000
32 #define RXSTAT_FRAME (1 << 0)
33 #define RXSTAT_PARITY (1 << 1)
34 #define RXSTAT_OVERRUN (1 << 2)
35 #define RXSTAT_ANYERR (RXSTAT_FRAME|RXSTAT_PARITY|RXSTAT_OVERRUN)
37 #define H_UBRLCR_BREAK (1 << 0)
38 #define H_UBRLCR_PARENB (1 << 1)
39 #define H_UBRLCR_PAREVN (1 << 2)
40 #define H_UBRLCR_STOPB (1 << 3)
41 #define H_UBRLCR_FIFO (1 << 4)
43 static const char serial21285_name[] = "Footbridge UART";
45 #define tx_enabled(port) ((port)->unused[0])
46 #define rx_enabled(port) ((port)->unused[1])
49 * The documented expression for selecting the divisor is:
50 * BAUD_BASE / baud - 1
51 * However, typically BAUD_BASE is not divisible by baud, so
52 * we want to select the divisor that gives us the minimum
53 * error. Therefore, we want:
54 * int(BAUD_BASE / baud - 0.5) ->
55 * int(BAUD_BASE / baud - (baud >> 1) / baud) ->
56 * int((BAUD_BASE - (baud >> 1)) / baud)
60 serial21285_stop_tx(struct uart_port *port, unsigned int tty_stop)
62 if (tx_enabled(port)) {
63 disable_irq(IRQ_CONTX);
69 serial21285_start_tx(struct uart_port *port, unsigned int tty_start)
71 if (!tx_enabled(port)) {
72 enable_irq(IRQ_CONTX);
77 static void serial21285_stop_rx(struct uart_port *port)
79 if (rx_enabled(port)) {
80 disable_irq(IRQ_CONRX);
85 static void serial21285_enable_ms(struct uart_port *port)
89 static irqreturn_t serial21285_rx_chars(int irq, void *dev_id, struct pt_regs *regs)
91 struct uart_port *port = dev_id;
92 struct tty_struct *tty = port->info->tty;
93 unsigned int status, ch, rxs, max_count = 256;
95 status = *CSR_UARTFLG;
96 while (!(status & 0x10) && max_count--) {
97 if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
98 tty->flip.work.func((void *)tty);
99 if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
100 printk(KERN_WARNING "TTY_DONT_FLIP set\n");
107 *tty->flip.char_buf_ptr = ch;
108 *tty->flip.flag_buf_ptr = TTY_NORMAL;
111 rxs = *CSR_RXSTAT | RXSTAT_DUMMY_READ;
112 if (rxs & RXSTAT_ANYERR) {
113 if (rxs & RXSTAT_PARITY)
114 port->icount.parity++;
115 else if (rxs & RXSTAT_FRAME)
116 port->icount.frame++;
117 if (rxs & RXSTAT_OVERRUN)
118 port->icount.overrun++;
120 rxs &= port->read_status_mask;
122 if (rxs & RXSTAT_PARITY)
123 *tty->flip.flag_buf_ptr = TTY_PARITY;
124 else if (rxs & RXSTAT_FRAME)
125 *tty->flip.flag_buf_ptr = TTY_FRAME;
128 if ((rxs & port->ignore_status_mask) == 0) {
129 tty->flip.flag_buf_ptr++;
130 tty->flip.char_buf_ptr++;
133 if ((rxs & RXSTAT_OVERRUN) &&
134 tty->flip.count < TTY_FLIPBUF_SIZE) {
136 * Overrun is special, since it's reported
137 * immediately, and doesn't affect the current
140 *tty->flip.char_buf_ptr++ = 0;
141 *tty->flip.flag_buf_ptr++ = TTY_OVERRUN;
144 status = *CSR_UARTFLG;
146 tty_flip_buffer_push(tty);
152 static irqreturn_t serial21285_tx_chars(int irq, void *dev_id, struct pt_regs *regs)
154 struct uart_port *port = dev_id;
155 struct circ_buf *xmit = &port->info->xmit;
159 *CSR_UARTDR = port->x_char;
164 if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
165 serial21285_stop_tx(port, 0);
170 *CSR_UARTDR = xmit->buf[xmit->tail];
171 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
173 if (uart_circ_empty(xmit))
175 } while (--count > 0 && !(*CSR_UARTFLG & 0x20));
177 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
178 uart_write_wakeup(port);
180 if (uart_circ_empty(xmit))
181 serial21285_stop_tx(port, 0);
187 static unsigned int serial21285_tx_empty(struct uart_port *port)
189 return (*CSR_UARTFLG & 8) ? 0 : TIOCSER_TEMT;
192 /* no modem control lines */
193 static unsigned int serial21285_get_mctrl(struct uart_port *port)
195 return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
198 static void serial21285_set_mctrl(struct uart_port *port, unsigned int mctrl)
202 static void serial21285_break_ctl(struct uart_port *port, int break_state)
207 spin_lock_irqsave(&port->lock, flags);
208 h_lcr = *CSR_H_UBRLCR;
210 h_lcr |= H_UBRLCR_BREAK;
212 h_lcr &= ~H_UBRLCR_BREAK;
213 *CSR_H_UBRLCR = h_lcr;
214 spin_unlock_irqrestore(&port->lock, flags);
217 static int serial21285_startup(struct uart_port *port)
221 tx_enabled(port) = 1;
222 rx_enabled(port) = 1;
224 ret = request_irq(IRQ_CONRX, serial21285_rx_chars, 0,
225 serial21285_name, port);
227 ret = request_irq(IRQ_CONTX, serial21285_tx_chars, 0,
228 serial21285_name, port);
230 free_irq(IRQ_CONRX, port);
236 static void serial21285_shutdown(struct uart_port *port)
238 free_irq(IRQ_CONTX, port);
239 free_irq(IRQ_CONRX, port);
243 serial21285_set_termios(struct uart_port *port, struct termios *termios,
247 unsigned int baud, quot, h_lcr;
250 * We don't support modem control lines.
252 termios->c_cflag &= ~(HUPCL | CRTSCTS | CMSPAR);
253 termios->c_cflag |= CLOCAL;
256 * We don't support BREAK character recognition.
258 termios->c_iflag &= ~(IGNBRK | BRKINT);
261 * Ask the core to calculate the divisor for us.
263 baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
264 quot = uart_get_divisor(port, baud);
266 switch (termios->c_cflag & CSIZE) {
281 if (termios->c_cflag & CSTOPB)
282 h_lcr |= H_UBRLCR_STOPB;
283 if (termios->c_cflag & PARENB) {
284 h_lcr |= H_UBRLCR_PARENB;
285 if (!(termios->c_cflag & PARODD))
286 h_lcr |= H_UBRLCR_PAREVN;
290 h_lcr |= H_UBRLCR_FIFO;
292 spin_lock_irqsave(&port->lock, flags);
295 * Update the per-port timeout.
297 uart_update_timeout(port, termios->c_cflag, baud);
300 * Which character status flags are we interested in?
302 port->read_status_mask = RXSTAT_OVERRUN;
303 if (termios->c_iflag & INPCK)
304 port->read_status_mask |= RXSTAT_FRAME | RXSTAT_PARITY;
307 * Which character status flags should we ignore?
309 port->ignore_status_mask = 0;
310 if (termios->c_iflag & IGNPAR)
311 port->ignore_status_mask |= RXSTAT_FRAME | RXSTAT_PARITY;
312 if (termios->c_iflag & IGNBRK && termios->c_iflag & IGNPAR)
313 port->ignore_status_mask |= RXSTAT_OVERRUN;
316 * Ignore all characters if CREAD is not set.
318 if ((termios->c_cflag & CREAD) == 0)
319 port->ignore_status_mask |= RXSTAT_DUMMY_READ;
324 *CSR_L_UBRLCR = quot & 0xff;
325 *CSR_M_UBRLCR = (quot >> 8) & 0x0f;
326 *CSR_H_UBRLCR = h_lcr;
329 spin_unlock_irqrestore(&port->lock, flags);
332 static const char *serial21285_type(struct uart_port *port)
334 return port->type == PORT_21285 ? "DC21285" : NULL;
337 static void serial21285_release_port(struct uart_port *port)
339 release_mem_region(port->mapbase, 32);
342 static int serial21285_request_port(struct uart_port *port)
344 return request_mem_region(port->mapbase, 32, serial21285_name)
345 != NULL ? 0 : -EBUSY;
348 static void serial21285_config_port(struct uart_port *port, int flags)
350 if (flags & UART_CONFIG_TYPE && serial21285_request_port(port) == 0)
351 port->type = PORT_21285;
355 * verify the new serial_struct (for TIOCSSERIAL).
357 static int serial21285_verify_port(struct uart_port *port, struct serial_struct *ser)
360 if (ser->type != PORT_UNKNOWN && ser->type != PORT_21285)
362 if (ser->irq != NO_IRQ)
364 if (ser->baud_base != port->uartclk / 16)
369 static struct uart_ops serial21285_ops = {
370 .tx_empty = serial21285_tx_empty,
371 .get_mctrl = serial21285_get_mctrl,
372 .set_mctrl = serial21285_set_mctrl,
373 .stop_tx = serial21285_stop_tx,
374 .start_tx = serial21285_start_tx,
375 .stop_rx = serial21285_stop_rx,
376 .enable_ms = serial21285_enable_ms,
377 .break_ctl = serial21285_break_ctl,
378 .startup = serial21285_startup,
379 .shutdown = serial21285_shutdown,
380 .set_termios = serial21285_set_termios,
381 .type = serial21285_type,
382 .release_port = serial21285_release_port,
383 .request_port = serial21285_request_port,
384 .config_port = serial21285_config_port,
385 .verify_port = serial21285_verify_port,
388 static struct uart_port serial21285_port = {
390 .mapbase = 0x42000160,
391 .iotype = SERIAL_IO_MEM,
395 .ops = &serial21285_ops,
396 .flags = ASYNC_BOOT_AUTOCONF,
399 static void serial21285_setup_ports(void)
401 serial21285_port.uartclk = mem_fclk_21285 / 4;
404 #ifdef CONFIG_SERIAL_21285_CONSOLE
407 serial21285_console_write(struct console *co, const char *s,
412 for (i = 0; i < count; i++) {
413 while (*CSR_UARTFLG & 0x20)
417 while (*CSR_UARTFLG & 0x20)
425 serial21285_get_options(struct uart_port *port, int *baud,
426 int *parity, int *bits)
428 if (*CSR_UARTCON == 1) {
432 switch (tmp & 0x60) {
448 if (tmp & H_UBRLCR_PARENB) {
450 if (tmp & H_UBRLCR_PAREVN)
454 tmp = *CSR_L_UBRLCR | (*CSR_M_UBRLCR << 8);
456 *baud = port->uartclk / (16 * (tmp + 1));
460 static int __init serial21285_console_setup(struct console *co, char *options)
462 struct uart_port *port = &serial21285_port;
468 if (machine_is_personal_server())
472 * Check whether an invalid uart number has been specified, and
473 * if so, search for the first available port that does have
477 uart_parse_options(options, &baud, &parity, &bits, &flow);
479 serial21285_get_options(port, &baud, &parity, &bits);
481 return uart_set_options(port, co, baud, parity, bits, flow);
484 extern struct uart_driver serial21285_reg;
486 static struct console serial21285_console =
488 .name = SERIAL_21285_NAME,
489 .write = serial21285_console_write,
490 .device = uart_console_device,
491 .setup = serial21285_console_setup,
492 .flags = CON_PRINTBUFFER,
494 .data = &serial21285_reg,
497 static int __init rs285_console_init(void)
499 serial21285_setup_ports();
500 register_console(&serial21285_console);
503 console_initcall(rs285_console_init);
505 #define SERIAL_21285_CONSOLE &serial21285_console
507 #define SERIAL_21285_CONSOLE NULL
510 static struct uart_driver serial21285_reg = {
511 .owner = THIS_MODULE,
512 .driver_name = "ttyFB",
514 .devfs_name = "ttyFB",
515 .major = SERIAL_21285_MAJOR,
516 .minor = SERIAL_21285_MINOR,
518 .cons = SERIAL_21285_CONSOLE,
521 static int __init serial21285_init(void)
525 printk(KERN_INFO "Serial: 21285 driver $Revision: 1.37 $\n");
527 serial21285_setup_ports();
529 ret = uart_register_driver(&serial21285_reg);
531 uart_add_one_port(&serial21285_reg, &serial21285_port);
536 static void __exit serial21285_exit(void)
538 uart_remove_one_port(&serial21285_reg, &serial21285_port);
539 uart_unregister_driver(&serial21285_reg);
542 module_init(serial21285_init);
543 module_exit(serial21285_exit);
545 MODULE_LICENSE("GPL");
546 MODULE_DESCRIPTION("Intel Footbridge (21285) serial driver $Revision: 1.37 $");
547 MODULE_ALIAS_CHARDEV(SERIAL_21285_MAJOR, SERIAL_21285_MINOR);