2 * linux/drivers/char/amba.c
4 * Driver for AMBA serial ports
6 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
8 * Copyright 1999 ARM Limited
9 * Copyright (C) 2000 Deep Blue Solutions Ltd.
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
25 * $Id: amba.c,v 1.41 2002/07/28 10:03:27 rmk Exp $
27 * This is a generic driver for ARM AMBA-type serial ports. They
28 * have a lot of 16550-like features, but are not register compatible.
29 * Note that although they do have CTS, DCD and DSR inputs, they do
30 * not have an RI input, nor do they have DTR or RTS outputs. If
31 * required, these have to be supplied via some other means (eg, GPIO)
32 * and hooked into this driver.
35 #if defined(CONFIG_SERIAL_AMBA_PL010_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
39 #include <linux/module.h>
40 #include <linux/ioport.h>
41 #include <linux/init.h>
42 #include <linux/console.h>
43 #include <linux/sysrq.h>
44 #include <linux/device.h>
45 #include <linux/tty.h>
46 #include <linux/tty_flip.h>
47 #include <linux/serial_core.h>
48 #include <linux/serial.h>
49 #include <linux/amba/bus.h>
50 #include <linux/amba/serial.h>
56 #define SERIAL_AMBA_MAJOR 204
57 #define SERIAL_AMBA_MINOR 16
58 #define SERIAL_AMBA_NR UART_NR
60 #define AMBA_ISR_PASS_LIMIT 256
62 #define UART_RX_DATA(s) (((s) & UART01x_FR_RXFE) == 0)
63 #define UART_TX_READY(s) (((s) & UART01x_FR_TXFF) == 0)
65 #define UART_DUMMY_RSR_RX 256
66 #define UART_PORT_SIZE 64
69 * We wrap our port structure around the generic uart_port.
71 struct uart_amba_port {
72 struct uart_port port;
73 struct amba_device *dev;
74 struct amba_pl010_data *data;
75 unsigned int old_status;
78 static void pl010_stop_tx(struct uart_port *port)
82 cr = readb(port->membase + UART010_CR);
83 cr &= ~UART010_CR_TIE;
84 writel(cr, port->membase + UART010_CR);
87 static void pl010_start_tx(struct uart_port *port)
91 cr = readb(port->membase + UART010_CR);
93 writel(cr, port->membase + UART010_CR);
96 static void pl010_stop_rx(struct uart_port *port)
100 cr = readb(port->membase + UART010_CR);
101 cr &= ~(UART010_CR_RIE | UART010_CR_RTIE);
102 writel(cr, port->membase + UART010_CR);
105 static void pl010_enable_ms(struct uart_port *port)
109 cr = readb(port->membase + UART010_CR);
110 cr |= UART010_CR_MSIE;
111 writel(cr, port->membase + UART010_CR);
116 pl010_rx_chars(struct uart_port *port, struct pt_regs *regs)
118 pl010_rx_chars(struct uart_port *port)
121 struct tty_struct *tty = port->info->tty;
122 unsigned int status, ch, flag, rsr, max_count = 256;
124 status = readb(port->membase + UART01x_FR);
125 while (UART_RX_DATA(status) && max_count--) {
126 ch = readb(port->membase + UART01x_DR);
132 * Note that the error handling code is
133 * out of the main execution path
135 rsr = readb(port->membase + UART01x_RSR) | UART_DUMMY_RSR_RX;
136 if (unlikely(rsr & UART01x_RSR_ANY)) {
137 if (rsr & UART01x_RSR_BE) {
138 rsr &= ~(UART01x_RSR_FE | UART01x_RSR_PE);
140 if (uart_handle_break(port))
142 } else if (rsr & UART01x_RSR_PE)
143 port->icount.parity++;
144 else if (rsr & UART01x_RSR_FE)
145 port->icount.frame++;
146 if (rsr & UART01x_RSR_OE)
147 port->icount.overrun++;
149 rsr &= port->read_status_mask;
151 if (rsr & UART01x_RSR_BE)
153 else if (rsr & UART01x_RSR_PE)
155 else if (rsr & UART01x_RSR_FE)
159 if (uart_handle_sysrq_char(port, ch, regs))
162 uart_insert_char(port, rsr, UART01x_RSR_OE, ch, flag);
165 status = readb(port->membase + UART01x_FR);
167 tty_flip_buffer_push(tty);
171 static void pl010_tx_chars(struct uart_port *port)
173 struct circ_buf *xmit = &port->info->xmit;
177 writel(port->x_char, port->membase + UART01x_DR);
182 if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
187 count = port->fifosize >> 1;
189 writel(xmit->buf[xmit->tail], port->membase + UART01x_DR);
190 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
192 if (uart_circ_empty(xmit))
194 } while (--count > 0);
196 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
197 uart_write_wakeup(port);
199 if (uart_circ_empty(xmit))
203 static void pl010_modem_status(struct uart_port *port)
205 struct uart_amba_port *uap = (struct uart_amba_port *)port;
206 unsigned int status, delta;
208 writel(0, uap->port.membase + UART010_ICR);
210 status = readb(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
212 delta = status ^ uap->old_status;
213 uap->old_status = status;
218 if (delta & UART01x_FR_DCD)
219 uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD);
221 if (delta & UART01x_FR_DSR)
222 uap->port.icount.dsr++;
224 if (delta & UART01x_FR_CTS)
225 uart_handle_cts_change(&uap->port, status & UART01x_FR_CTS);
227 wake_up_interruptible(&uap->port.info->delta_msr_wait);
230 static irqreturn_t pl010_int(int irq, void *dev_id, struct pt_regs *regs)
232 struct uart_port *port = dev_id;
233 unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
236 spin_lock(&port->lock);
238 status = readb(port->membase + UART010_IIR);
241 if (status & (UART010_IIR_RTIS | UART010_IIR_RIS))
243 pl010_rx_chars(port, regs);
245 pl010_rx_chars(port);
247 if (status & UART010_IIR_MIS)
248 pl010_modem_status(port);
249 if (status & UART010_IIR_TIS)
250 pl010_tx_chars(port);
252 if (pass_counter-- == 0)
255 status = readb(port->membase + UART010_IIR);
256 } while (status & (UART010_IIR_RTIS | UART010_IIR_RIS |
261 spin_unlock(&port->lock);
263 return IRQ_RETVAL(handled);
266 static unsigned int pl010_tx_empty(struct uart_port *port)
268 return readb(port->membase + UART01x_FR) & UART01x_FR_BUSY ? 0 : TIOCSER_TEMT;
271 static unsigned int pl010_get_mctrl(struct uart_port *port)
273 unsigned int result = 0;
276 status = readb(port->membase + UART01x_FR);
277 if (status & UART01x_FR_DCD)
279 if (status & UART01x_FR_DSR)
281 if (status & UART01x_FR_CTS)
287 static void pl010_set_mctrl(struct uart_port *port, unsigned int mctrl)
289 struct uart_amba_port *uap = (struct uart_amba_port *)port;
292 uap->data->set_mctrl(uap->dev, uap->port.membase, mctrl);
295 static void pl010_break_ctl(struct uart_port *port, int break_state)
300 spin_lock_irqsave(&port->lock, flags);
301 lcr_h = readb(port->membase + UART010_LCRH);
302 if (break_state == -1)
303 lcr_h |= UART01x_LCRH_BRK;
305 lcr_h &= ~UART01x_LCRH_BRK;
306 writel(lcr_h, port->membase + UART010_LCRH);
307 spin_unlock_irqrestore(&port->lock, flags);
310 static int pl010_startup(struct uart_port *port)
312 struct uart_amba_port *uap = (struct uart_amba_port *)port;
318 retval = request_irq(port->irq, pl010_int, 0, "uart-pl010", port);
323 * initialise the old status of the modem signals
325 uap->old_status = readb(port->membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
328 * Finally, enable interrupts
330 writel(UART01x_CR_UARTEN | UART010_CR_RIE | UART010_CR_RTIE,
331 port->membase + UART010_CR);
336 static void pl010_shutdown(struct uart_port *port)
341 free_irq(port->irq, port);
344 * disable all interrupts, disable the port
346 writel(0, port->membase + UART010_CR);
348 /* disable break condition and fifos */
349 writel(readb(port->membase + UART010_LCRH) &
350 ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN),
351 port->membase + UART010_LCRH);
355 pl010_set_termios(struct uart_port *port, struct termios *termios,
358 unsigned int lcr_h, old_cr;
360 unsigned int baud, quot;
363 * Ask the core to calculate the divisor for us.
365 baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
366 quot = uart_get_divisor(port, baud);
368 switch (termios->c_cflag & CSIZE) {
370 lcr_h = UART01x_LCRH_WLEN_5;
373 lcr_h = UART01x_LCRH_WLEN_6;
376 lcr_h = UART01x_LCRH_WLEN_7;
379 lcr_h = UART01x_LCRH_WLEN_8;
382 if (termios->c_cflag & CSTOPB)
383 lcr_h |= UART01x_LCRH_STP2;
384 if (termios->c_cflag & PARENB) {
385 lcr_h |= UART01x_LCRH_PEN;
386 if (!(termios->c_cflag & PARODD))
387 lcr_h |= UART01x_LCRH_EPS;
389 if (port->fifosize > 1)
390 lcr_h |= UART01x_LCRH_FEN;
392 spin_lock_irqsave(&port->lock, flags);
395 * Update the per-port timeout.
397 uart_update_timeout(port, termios->c_cflag, baud);
399 port->read_status_mask = UART01x_RSR_OE;
400 if (termios->c_iflag & INPCK)
401 port->read_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
402 if (termios->c_iflag & (BRKINT | PARMRK))
403 port->read_status_mask |= UART01x_RSR_BE;
406 * Characters to ignore
408 port->ignore_status_mask = 0;
409 if (termios->c_iflag & IGNPAR)
410 port->ignore_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
411 if (termios->c_iflag & IGNBRK) {
412 port->ignore_status_mask |= UART01x_RSR_BE;
414 * If we're ignoring parity and break indicators,
415 * ignore overruns too (for real raw support).
417 if (termios->c_iflag & IGNPAR)
418 port->ignore_status_mask |= UART01x_RSR_OE;
422 * Ignore all characters if CREAD is not set.
424 if ((termios->c_cflag & CREAD) == 0)
425 port->ignore_status_mask |= UART_DUMMY_RSR_RX;
427 /* first, disable everything */
428 old_cr = readb(port->membase + UART010_CR) & ~UART010_CR_MSIE;
430 if (UART_ENABLE_MS(port, termios->c_cflag))
431 old_cr |= UART010_CR_MSIE;
433 writel(0, port->membase + UART010_CR);
437 writel((quot & 0xf00) >> 8, port->membase + UART010_LCRM);
438 writel(quot & 0xff, port->membase + UART010_LCRL);
441 * ----------v----------v----------v----------v-----
442 * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L
443 * ----------^----------^----------^----------^-----
445 writel(lcr_h, port->membase + UART010_LCRH);
446 writel(old_cr, port->membase + UART010_CR);
448 spin_unlock_irqrestore(&port->lock, flags);
451 static const char *pl010_type(struct uart_port *port)
453 return port->type == PORT_AMBA ? "AMBA" : NULL;
457 * Release the memory region(s) being used by 'port'
459 static void pl010_release_port(struct uart_port *port)
461 release_mem_region(port->mapbase, UART_PORT_SIZE);
465 * Request the memory region(s) being used by 'port'
467 static int pl010_request_port(struct uart_port *port)
469 return request_mem_region(port->mapbase, UART_PORT_SIZE, "uart-pl010")
470 != NULL ? 0 : -EBUSY;
474 * Configure/autoconfigure the port.
476 static void pl010_config_port(struct uart_port *port, int flags)
478 if (flags & UART_CONFIG_TYPE) {
479 port->type = PORT_AMBA;
480 pl010_request_port(port);
485 * verify the new serial_struct (for TIOCSSERIAL).
487 static int pl010_verify_port(struct uart_port *port, struct serial_struct *ser)
490 if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA)
492 if (ser->irq < 0 || ser->irq >= NR_IRQS)
494 if (ser->baud_base < 9600)
499 static struct uart_ops amba_pl010_pops = {
500 .tx_empty = pl010_tx_empty,
501 .set_mctrl = pl010_set_mctrl,
502 .get_mctrl = pl010_get_mctrl,
503 .stop_tx = pl010_stop_tx,
504 .start_tx = pl010_start_tx,
505 .stop_rx = pl010_stop_rx,
506 .enable_ms = pl010_enable_ms,
507 .break_ctl = pl010_break_ctl,
508 .startup = pl010_startup,
509 .shutdown = pl010_shutdown,
510 .set_termios = pl010_set_termios,
512 .release_port = pl010_release_port,
513 .request_port = pl010_request_port,
514 .config_port = pl010_config_port,
515 .verify_port = pl010_verify_port,
518 static struct uart_amba_port *amba_ports[UART_NR];
520 #ifdef CONFIG_SERIAL_AMBA_PL010_CONSOLE
522 static void pl010_console_putchar(struct uart_port *port, int ch)
527 status = readb(port->membase + UART01x_FR);
529 } while (!UART_TX_READY(status));
530 writel(ch, port->membase + UART01x_DR);
534 pl010_console_write(struct console *co, const char *s, unsigned int count)
536 struct uart_port *port = &amba_ports[co->index]->port;
537 unsigned int status, old_cr;
540 * First save the CR then disable the interrupts
542 old_cr = readb(port->membase + UART010_CR);
543 writel(UART01x_CR_UARTEN, port->membase + UART010_CR);
545 uart_console_write(port, s, count, pl010_console_putchar);
548 * Finally, wait for transmitter to become empty
549 * and restore the TCR
552 status = readb(port->membase + UART01x_FR);
554 } while (status & UART01x_FR_BUSY);
555 writel(old_cr, port->membase + UART010_CR);
559 pl010_console_get_options(struct uart_port *port, int *baud,
560 int *parity, int *bits)
562 if (readb(port->membase + UART010_CR) & UART01x_CR_UARTEN) {
563 unsigned int lcr_h, quot;
564 lcr_h = readb(port->membase + UART010_LCRH);
567 if (lcr_h & UART01x_LCRH_PEN) {
568 if (lcr_h & UART01x_LCRH_EPS)
574 if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7)
579 quot = readb(port->membase + UART010_LCRL) | readb(port->membase + UART010_LCRM) << 8;
580 *baud = port->uartclk / (16 * (quot + 1));
584 static int __init pl010_console_setup(struct console *co, char *options)
586 struct uart_port *port;
593 * Check whether an invalid uart number has been specified, and
594 * if so, search for the first available port that does have
597 if (co->index >= UART_NR)
599 port = &amba_ports[co->index]->port;
602 uart_parse_options(options, &baud, &parity, &bits, &flow);
604 pl010_console_get_options(port, &baud, &parity, &bits);
606 return uart_set_options(port, co, baud, parity, bits, flow);
609 static struct uart_driver amba_reg;
610 static struct console amba_console = {
612 .write = pl010_console_write,
613 .device = uart_console_device,
614 .setup = pl010_console_setup,
615 .flags = CON_PRINTBUFFER,
620 #define AMBA_CONSOLE &amba_console
622 #define AMBA_CONSOLE NULL
625 static struct uart_driver amba_reg = {
626 .owner = THIS_MODULE,
627 .driver_name = "ttyAM",
629 .major = SERIAL_AMBA_MAJOR,
630 .minor = SERIAL_AMBA_MINOR,
632 .cons = AMBA_CONSOLE,
635 static int pl010_probe(struct amba_device *dev, void *id)
637 struct uart_amba_port *port;
641 for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
642 if (amba_ports[i] == NULL)
645 if (i == ARRAY_SIZE(amba_ports)) {
650 port = kzalloc(sizeof(struct uart_amba_port), GFP_KERNEL);
656 base = ioremap(dev->res.start, PAGE_SIZE);
662 port->port.dev = &dev->dev;
663 port->port.mapbase = dev->res.start;
664 port->port.membase = base;
665 port->port.iotype = UPIO_MEM;
666 port->port.irq = dev->irq[0];
667 port->port.uartclk = 14745600;
668 port->port.fifosize = 16;
669 port->port.ops = &amba_pl010_pops;
670 port->port.flags = UPF_BOOT_AUTOCONF;
673 port->data = dev->dev.platform_data;
675 amba_ports[i] = port;
677 amba_set_drvdata(dev, port);
678 ret = uart_add_one_port(&amba_reg, &port->port);
680 amba_set_drvdata(dev, NULL);
681 amba_ports[i] = NULL;
691 static int pl010_remove(struct amba_device *dev)
693 struct uart_amba_port *port = amba_get_drvdata(dev);
696 amba_set_drvdata(dev, NULL);
698 uart_remove_one_port(&amba_reg, &port->port);
700 for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
701 if (amba_ports[i] == port)
702 amba_ports[i] = NULL;
704 iounmap(port->port.membase);
710 static int pl010_suspend(struct amba_device *dev, pm_message_t state)
712 struct uart_amba_port *uap = amba_get_drvdata(dev);
715 uart_suspend_port(&amba_reg, &uap->port);
720 static int pl010_resume(struct amba_device *dev)
722 struct uart_amba_port *uap = amba_get_drvdata(dev);
725 uart_resume_port(&amba_reg, &uap->port);
730 static struct amba_id pl010_ids[] __initdata = {
738 static struct amba_driver pl010_driver = {
740 .name = "uart-pl010",
742 .id_table = pl010_ids,
743 .probe = pl010_probe,
744 .remove = pl010_remove,
745 .suspend = pl010_suspend,
746 .resume = pl010_resume,
749 static int __init pl010_init(void)
753 printk(KERN_INFO "Serial: AMBA driver $Revision: 1.41 $\n");
755 ret = uart_register_driver(&amba_reg);
757 ret = amba_driver_register(&pl010_driver);
759 uart_unregister_driver(&amba_reg);
764 static void __exit pl010_exit(void)
766 amba_driver_unregister(&pl010_driver);
767 uart_unregister_driver(&amba_reg);
770 module_init(pl010_init);
771 module_exit(pl010_exit);
773 MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
774 MODULE_DESCRIPTION("ARM AMBA serial port driver $Revision: 1.41 $");
775 MODULE_LICENSE("GPL");