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)
80 struct uart_amba_port *uap = (struct uart_amba_port *)port;
83 cr = readb(uap->port.membase + UART010_CR);
84 cr &= ~UART010_CR_TIE;
85 writel(cr, uap->port.membase + UART010_CR);
88 static void pl010_start_tx(struct uart_port *port)
90 struct uart_amba_port *uap = (struct uart_amba_port *)port;
93 cr = readb(uap->port.membase + UART010_CR);
95 writel(cr, uap->port.membase + UART010_CR);
98 static void pl010_stop_rx(struct uart_port *port)
100 struct uart_amba_port *uap = (struct uart_amba_port *)port;
103 cr = readb(uap->port.membase + UART010_CR);
104 cr &= ~(UART010_CR_RIE | UART010_CR_RTIE);
105 writel(cr, uap->port.membase + UART010_CR);
108 static void pl010_enable_ms(struct uart_port *port)
110 struct uart_amba_port *uap = (struct uart_amba_port *)port;
113 cr = readb(uap->port.membase + UART010_CR);
114 cr |= UART010_CR_MSIE;
115 writel(cr, uap->port.membase + UART010_CR);
118 static void pl010_rx_chars(struct uart_amba_port *uap)
120 struct tty_struct *tty = uap->port.info->tty;
121 unsigned int status, ch, flag, rsr, max_count = 256;
123 status = readb(uap->port.membase + UART01x_FR);
124 while (UART_RX_DATA(status) && max_count--) {
125 ch = readb(uap->port.membase + UART01x_DR);
128 uap->port.icount.rx++;
131 * Note that the error handling code is
132 * out of the main execution path
134 rsr = readb(uap->port.membase + UART01x_RSR) | UART_DUMMY_RSR_RX;
135 if (unlikely(rsr & UART01x_RSR_ANY)) {
136 writel(0, uap->port.membase + UART01x_ECR);
138 if (rsr & UART01x_RSR_BE) {
139 rsr &= ~(UART01x_RSR_FE | UART01x_RSR_PE);
140 uap->port.icount.brk++;
141 if (uart_handle_break(&uap->port))
143 } else if (rsr & UART01x_RSR_PE)
144 uap->port.icount.parity++;
145 else if (rsr & UART01x_RSR_FE)
146 uap->port.icount.frame++;
147 if (rsr & UART01x_RSR_OE)
148 uap->port.icount.overrun++;
150 rsr &= uap->port.read_status_mask;
152 if (rsr & UART01x_RSR_BE)
154 else if (rsr & UART01x_RSR_PE)
156 else if (rsr & UART01x_RSR_FE)
160 if (uart_handle_sysrq_char(&uap->port, ch))
163 uart_insert_char(&uap->port, rsr, UART01x_RSR_OE, ch, flag);
166 status = readb(uap->port.membase + UART01x_FR);
168 tty_flip_buffer_push(tty);
172 static void pl010_tx_chars(struct uart_amba_port *uap)
174 struct circ_buf *xmit = &uap->port.info->xmit;
177 if (uap->port.x_char) {
178 writel(uap->port.x_char, uap->port.membase + UART01x_DR);
179 uap->port.icount.tx++;
180 uap->port.x_char = 0;
183 if (uart_circ_empty(xmit) || uart_tx_stopped(&uap->port)) {
184 pl010_stop_tx(&uap->port);
188 count = uap->port.fifosize >> 1;
190 writel(xmit->buf[xmit->tail], uap->port.membase + UART01x_DR);
191 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
192 uap->port.icount.tx++;
193 if (uart_circ_empty(xmit))
195 } while (--count > 0);
197 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
198 uart_write_wakeup(&uap->port);
200 if (uart_circ_empty(xmit))
201 pl010_stop_tx(&uap->port);
204 static void pl010_modem_status(struct uart_amba_port *uap)
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)
232 struct uart_amba_port *uap = dev_id;
233 unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
236 spin_lock(&uap->port.lock);
238 status = readb(uap->port.membase + UART010_IIR);
241 if (status & (UART010_IIR_RTIS | UART010_IIR_RIS))
243 if (status & UART010_IIR_MIS)
244 pl010_modem_status(uap);
245 if (status & UART010_IIR_TIS)
248 if (pass_counter-- == 0)
251 status = readb(uap->port.membase + UART010_IIR);
252 } while (status & (UART010_IIR_RTIS | UART010_IIR_RIS |
257 spin_unlock(&uap->port.lock);
259 return IRQ_RETVAL(handled);
262 static unsigned int pl010_tx_empty(struct uart_port *port)
264 struct uart_amba_port *uap = (struct uart_amba_port *)port;
265 unsigned int status = readb(uap->port.membase + UART01x_FR);
266 return status & UART01x_FR_BUSY ? 0 : TIOCSER_TEMT;
269 static unsigned int pl010_get_mctrl(struct uart_port *port)
271 struct uart_amba_port *uap = (struct uart_amba_port *)port;
272 unsigned int result = 0;
275 status = readb(uap->port.membase + UART01x_FR);
276 if (status & UART01x_FR_DCD)
278 if (status & UART01x_FR_DSR)
280 if (status & UART01x_FR_CTS)
286 static void pl010_set_mctrl(struct uart_port *port, unsigned int mctrl)
288 struct uart_amba_port *uap = (struct uart_amba_port *)port;
291 uap->data->set_mctrl(uap->dev, uap->port.membase, mctrl);
294 static void pl010_break_ctl(struct uart_port *port, int break_state)
296 struct uart_amba_port *uap = (struct uart_amba_port *)port;
300 spin_lock_irqsave(&uap->port.lock, flags);
301 lcr_h = readb(uap->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, uap->port.membase + UART010_LCRH);
307 spin_unlock_irqrestore(&uap->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(uap->port.irq, pl010_int, 0, "uart-pl010", uap);
323 * initialise the old status of the modem signals
325 uap->old_status = readb(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
328 * Finally, enable interrupts
330 writel(UART01x_CR_UARTEN | UART010_CR_RIE | UART010_CR_RTIE,
331 uap->port.membase + UART010_CR);
336 static void pl010_shutdown(struct uart_port *port)
338 struct uart_amba_port *uap = (struct uart_amba_port *)port;
343 free_irq(uap->port.irq, uap);
346 * disable all interrupts, disable the port
348 writel(0, uap->port.membase + UART010_CR);
350 /* disable break condition and fifos */
351 writel(readb(uap->port.membase + UART010_LCRH) &
352 ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN),
353 uap->port.membase + UART010_LCRH);
357 pl010_set_termios(struct uart_port *port, struct ktermios *termios,
358 struct ktermios *old)
360 struct uart_amba_port *uap = (struct uart_amba_port *)port;
361 unsigned int lcr_h, old_cr;
363 unsigned int baud, quot;
366 * Ask the core to calculate the divisor for us.
368 baud = uart_get_baud_rate(port, termios, old, 0, uap->port.uartclk/16);
369 quot = uart_get_divisor(port, baud);
371 switch (termios->c_cflag & CSIZE) {
373 lcr_h = UART01x_LCRH_WLEN_5;
376 lcr_h = UART01x_LCRH_WLEN_6;
379 lcr_h = UART01x_LCRH_WLEN_7;
382 lcr_h = UART01x_LCRH_WLEN_8;
385 if (termios->c_cflag & CSTOPB)
386 lcr_h |= UART01x_LCRH_STP2;
387 if (termios->c_cflag & PARENB) {
388 lcr_h |= UART01x_LCRH_PEN;
389 if (!(termios->c_cflag & PARODD))
390 lcr_h |= UART01x_LCRH_EPS;
392 if (uap->port.fifosize > 1)
393 lcr_h |= UART01x_LCRH_FEN;
395 spin_lock_irqsave(&uap->port.lock, flags);
398 * Update the per-port timeout.
400 uart_update_timeout(port, termios->c_cflag, baud);
402 uap->port.read_status_mask = UART01x_RSR_OE;
403 if (termios->c_iflag & INPCK)
404 uap->port.read_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
405 if (termios->c_iflag & (BRKINT | PARMRK))
406 uap->port.read_status_mask |= UART01x_RSR_BE;
409 * Characters to ignore
411 uap->port.ignore_status_mask = 0;
412 if (termios->c_iflag & IGNPAR)
413 uap->port.ignore_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
414 if (termios->c_iflag & IGNBRK) {
415 uap->port.ignore_status_mask |= UART01x_RSR_BE;
417 * If we're ignoring parity and break indicators,
418 * ignore overruns too (for real raw support).
420 if (termios->c_iflag & IGNPAR)
421 uap->port.ignore_status_mask |= UART01x_RSR_OE;
425 * Ignore all characters if CREAD is not set.
427 if ((termios->c_cflag & CREAD) == 0)
428 uap->port.ignore_status_mask |= UART_DUMMY_RSR_RX;
430 /* first, disable everything */
431 old_cr = readb(uap->port.membase + UART010_CR) & ~UART010_CR_MSIE;
433 if (UART_ENABLE_MS(port, termios->c_cflag))
434 old_cr |= UART010_CR_MSIE;
436 writel(0, uap->port.membase + UART010_CR);
440 writel((quot & 0xf00) >> 8, uap->port.membase + UART010_LCRM);
441 writel(quot & 0xff, uap->port.membase + UART010_LCRL);
444 * ----------v----------v----------v----------v-----
445 * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L
446 * ----------^----------^----------^----------^-----
448 writel(lcr_h, uap->port.membase + UART010_LCRH);
449 writel(old_cr, uap->port.membase + UART010_CR);
451 spin_unlock_irqrestore(&uap->port.lock, flags);
454 static const char *pl010_type(struct uart_port *port)
456 return port->type == PORT_AMBA ? "AMBA" : NULL;
460 * Release the memory region(s) being used by 'port'
462 static void pl010_release_port(struct uart_port *port)
464 release_mem_region(port->mapbase, UART_PORT_SIZE);
468 * Request the memory region(s) being used by 'port'
470 static int pl010_request_port(struct uart_port *port)
472 return request_mem_region(port->mapbase, UART_PORT_SIZE, "uart-pl010")
473 != NULL ? 0 : -EBUSY;
477 * Configure/autoconfigure the port.
479 static void pl010_config_port(struct uart_port *port, int flags)
481 if (flags & UART_CONFIG_TYPE) {
482 port->type = PORT_AMBA;
483 pl010_request_port(port);
488 * verify the new serial_struct (for TIOCSSERIAL).
490 static int pl010_verify_port(struct uart_port *port, struct serial_struct *ser)
493 if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA)
495 if (ser->irq < 0 || ser->irq >= NR_IRQS)
497 if (ser->baud_base < 9600)
502 static struct uart_ops amba_pl010_pops = {
503 .tx_empty = pl010_tx_empty,
504 .set_mctrl = pl010_set_mctrl,
505 .get_mctrl = pl010_get_mctrl,
506 .stop_tx = pl010_stop_tx,
507 .start_tx = pl010_start_tx,
508 .stop_rx = pl010_stop_rx,
509 .enable_ms = pl010_enable_ms,
510 .break_ctl = pl010_break_ctl,
511 .startup = pl010_startup,
512 .shutdown = pl010_shutdown,
513 .set_termios = pl010_set_termios,
515 .release_port = pl010_release_port,
516 .request_port = pl010_request_port,
517 .config_port = pl010_config_port,
518 .verify_port = pl010_verify_port,
521 static struct uart_amba_port *amba_ports[UART_NR];
523 #ifdef CONFIG_SERIAL_AMBA_PL010_CONSOLE
525 static void pl010_console_putchar(struct uart_port *port, int ch)
527 struct uart_amba_port *uap = (struct uart_amba_port *)port;
531 status = readb(uap->port.membase + UART01x_FR);
533 } while (!UART_TX_READY(status));
534 writel(ch, uap->port.membase + UART01x_DR);
538 pl010_console_write(struct console *co, const char *s, unsigned int count)
540 struct uart_amba_port *uap = amba_ports[co->index];
541 unsigned int status, old_cr;
544 * First save the CR then disable the interrupts
546 old_cr = readb(uap->port.membase + UART010_CR);
547 writel(UART01x_CR_UARTEN, uap->port.membase + UART010_CR);
549 uart_console_write(&uap->port, s, count, pl010_console_putchar);
552 * Finally, wait for transmitter to become empty
553 * and restore the TCR
556 status = readb(uap->port.membase + UART01x_FR);
558 } while (status & UART01x_FR_BUSY);
559 writel(old_cr, uap->port.membase + UART010_CR);
563 pl010_console_get_options(struct uart_amba_port *uap, int *baud,
564 int *parity, int *bits)
566 if (readb(uap->port.membase + UART010_CR) & UART01x_CR_UARTEN) {
567 unsigned int lcr_h, quot;
568 lcr_h = readb(uap->port.membase + UART010_LCRH);
571 if (lcr_h & UART01x_LCRH_PEN) {
572 if (lcr_h & UART01x_LCRH_EPS)
578 if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7)
583 quot = readb(uap->port.membase + UART010_LCRL) |
584 readb(uap->port.membase + UART010_LCRM) << 8;
585 *baud = uap->port.uartclk / (16 * (quot + 1));
589 static int __init pl010_console_setup(struct console *co, char *options)
591 struct uart_amba_port *uap;
598 * Check whether an invalid uart number has been specified, and
599 * if so, search for the first available port that does have
602 if (co->index >= UART_NR)
604 uap = amba_ports[co->index];
609 uart_parse_options(options, &baud, &parity, &bits, &flow);
611 pl010_console_get_options(uap, &baud, &parity, &bits);
613 return uart_set_options(&uap->port, co, baud, parity, bits, flow);
616 static struct uart_driver amba_reg;
617 static struct console amba_console = {
619 .write = pl010_console_write,
620 .device = uart_console_device,
621 .setup = pl010_console_setup,
622 .flags = CON_PRINTBUFFER,
627 #define AMBA_CONSOLE &amba_console
629 #define AMBA_CONSOLE NULL
632 static struct uart_driver amba_reg = {
633 .owner = THIS_MODULE,
634 .driver_name = "ttyAM",
636 .major = SERIAL_AMBA_MAJOR,
637 .minor = SERIAL_AMBA_MINOR,
639 .cons = AMBA_CONSOLE,
642 static int pl010_probe(struct amba_device *dev, void *id)
644 struct uart_amba_port *uap;
648 for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
649 if (amba_ports[i] == NULL)
652 if (i == ARRAY_SIZE(amba_ports)) {
657 uap = kzalloc(sizeof(struct uart_amba_port), GFP_KERNEL);
663 base = ioremap(dev->res.start, PAGE_SIZE);
669 uap->port.dev = &dev->dev;
670 uap->port.mapbase = dev->res.start;
671 uap->port.membase = base;
672 uap->port.iotype = UPIO_MEM;
673 uap->port.irq = dev->irq[0];
674 uap->port.uartclk = 14745600;
675 uap->port.fifosize = 16;
676 uap->port.ops = &amba_pl010_pops;
677 uap->port.flags = UPF_BOOT_AUTOCONF;
680 uap->data = dev->dev.platform_data;
684 amba_set_drvdata(dev, uap);
685 ret = uart_add_one_port(&amba_reg, &uap->port);
687 amba_set_drvdata(dev, NULL);
688 amba_ports[i] = NULL;
697 static int pl010_remove(struct amba_device *dev)
699 struct uart_amba_port *uap = amba_get_drvdata(dev);
702 amba_set_drvdata(dev, NULL);
704 uart_remove_one_port(&amba_reg, &uap->port);
706 for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
707 if (amba_ports[i] == uap)
708 amba_ports[i] = NULL;
710 iounmap(uap->port.membase);
715 static int pl010_suspend(struct amba_device *dev, pm_message_t state)
717 struct uart_amba_port *uap = amba_get_drvdata(dev);
720 uart_suspend_port(&amba_reg, &uap->port);
725 static int pl010_resume(struct amba_device *dev)
727 struct uart_amba_port *uap = amba_get_drvdata(dev);
730 uart_resume_port(&amba_reg, &uap->port);
735 static struct amba_id pl010_ids[] __initdata = {
743 static struct amba_driver pl010_driver = {
745 .name = "uart-pl010",
747 .id_table = pl010_ids,
748 .probe = pl010_probe,
749 .remove = pl010_remove,
750 .suspend = pl010_suspend,
751 .resume = pl010_resume,
754 static int __init pl010_init(void)
758 printk(KERN_INFO "Serial: AMBA driver $Revision: 1.41 $\n");
760 ret = uart_register_driver(&amba_reg);
762 ret = amba_driver_register(&pl010_driver);
764 uart_unregister_driver(&amba_reg);
769 static void __exit pl010_exit(void)
771 amba_driver_unregister(&pl010_driver);
772 uart_unregister_driver(&amba_reg);
775 module_init(pl010_init);
776 module_exit(pl010_exit);
778 MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
779 MODULE_DESCRIPTION("ARM AMBA serial port driver $Revision: 1.41 $");
780 MODULE_LICENSE("GPL");