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);
114 static void pl010_rx_chars(struct uart_port *port)
116 struct tty_struct *tty = port->info->tty;
117 unsigned int status, ch, flag, rsr, max_count = 256;
119 status = readb(port->membase + UART01x_FR);
120 while (UART_RX_DATA(status) && max_count--) {
121 ch = readb(port->membase + UART01x_DR);
127 * Note that the error handling code is
128 * out of the main execution path
130 rsr = readb(port->membase + UART01x_RSR) | UART_DUMMY_RSR_RX;
131 if (unlikely(rsr & UART01x_RSR_ANY)) {
132 if (rsr & UART01x_RSR_BE) {
133 rsr &= ~(UART01x_RSR_FE | UART01x_RSR_PE);
135 if (uart_handle_break(port))
137 } else if (rsr & UART01x_RSR_PE)
138 port->icount.parity++;
139 else if (rsr & UART01x_RSR_FE)
140 port->icount.frame++;
141 if (rsr & UART01x_RSR_OE)
142 port->icount.overrun++;
144 rsr &= port->read_status_mask;
146 if (rsr & UART01x_RSR_BE)
148 else if (rsr & UART01x_RSR_PE)
150 else if (rsr & UART01x_RSR_FE)
154 if (uart_handle_sysrq_char(port, ch))
157 uart_insert_char(port, rsr, UART01x_RSR_OE, ch, flag);
160 status = readb(port->membase + UART01x_FR);
162 tty_flip_buffer_push(tty);
166 static void pl010_tx_chars(struct uart_port *port)
168 struct circ_buf *xmit = &port->info->xmit;
172 writel(port->x_char, port->membase + UART01x_DR);
177 if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
182 count = port->fifosize >> 1;
184 writel(xmit->buf[xmit->tail], port->membase + UART01x_DR);
185 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
187 if (uart_circ_empty(xmit))
189 } while (--count > 0);
191 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
192 uart_write_wakeup(port);
194 if (uart_circ_empty(xmit))
198 static void pl010_modem_status(struct uart_port *port)
200 struct uart_amba_port *uap = (struct uart_amba_port *)port;
201 unsigned int status, delta;
203 writel(0, uap->port.membase + UART010_ICR);
205 status = readb(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
207 delta = status ^ uap->old_status;
208 uap->old_status = status;
213 if (delta & UART01x_FR_DCD)
214 uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD);
216 if (delta & UART01x_FR_DSR)
217 uap->port.icount.dsr++;
219 if (delta & UART01x_FR_CTS)
220 uart_handle_cts_change(&uap->port, status & UART01x_FR_CTS);
222 wake_up_interruptible(&uap->port.info->delta_msr_wait);
225 static irqreturn_t pl010_int(int irq, void *dev_id)
227 struct uart_port *port = dev_id;
228 unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
231 spin_lock(&port->lock);
233 status = readb(port->membase + UART010_IIR);
236 if (status & (UART010_IIR_RTIS | UART010_IIR_RIS))
237 pl010_rx_chars(port);
238 if (status & UART010_IIR_MIS)
239 pl010_modem_status(port);
240 if (status & UART010_IIR_TIS)
241 pl010_tx_chars(port);
243 if (pass_counter-- == 0)
246 status = readb(port->membase + UART010_IIR);
247 } while (status & (UART010_IIR_RTIS | UART010_IIR_RIS |
252 spin_unlock(&port->lock);
254 return IRQ_RETVAL(handled);
257 static unsigned int pl010_tx_empty(struct uart_port *port)
259 return readb(port->membase + UART01x_FR) & UART01x_FR_BUSY ? 0 : TIOCSER_TEMT;
262 static unsigned int pl010_get_mctrl(struct uart_port *port)
264 unsigned int result = 0;
267 status = readb(port->membase + UART01x_FR);
268 if (status & UART01x_FR_DCD)
270 if (status & UART01x_FR_DSR)
272 if (status & UART01x_FR_CTS)
278 static void pl010_set_mctrl(struct uart_port *port, unsigned int mctrl)
280 struct uart_amba_port *uap = (struct uart_amba_port *)port;
283 uap->data->set_mctrl(uap->dev, uap->port.membase, mctrl);
286 static void pl010_break_ctl(struct uart_port *port, int break_state)
291 spin_lock_irqsave(&port->lock, flags);
292 lcr_h = readb(port->membase + UART010_LCRH);
293 if (break_state == -1)
294 lcr_h |= UART01x_LCRH_BRK;
296 lcr_h &= ~UART01x_LCRH_BRK;
297 writel(lcr_h, port->membase + UART010_LCRH);
298 spin_unlock_irqrestore(&port->lock, flags);
301 static int pl010_startup(struct uart_port *port)
303 struct uart_amba_port *uap = (struct uart_amba_port *)port;
309 retval = request_irq(port->irq, pl010_int, 0, "uart-pl010", port);
314 * initialise the old status of the modem signals
316 uap->old_status = readb(port->membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
319 * Finally, enable interrupts
321 writel(UART01x_CR_UARTEN | UART010_CR_RIE | UART010_CR_RTIE,
322 port->membase + UART010_CR);
327 static void pl010_shutdown(struct uart_port *port)
332 free_irq(port->irq, port);
335 * disable all interrupts, disable the port
337 writel(0, port->membase + UART010_CR);
339 /* disable break condition and fifos */
340 writel(readb(port->membase + UART010_LCRH) &
341 ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN),
342 port->membase + UART010_LCRH);
346 pl010_set_termios(struct uart_port *port, struct termios *termios,
349 unsigned int lcr_h, old_cr;
351 unsigned int baud, quot;
354 * Ask the core to calculate the divisor for us.
356 baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
357 quot = uart_get_divisor(port, baud);
359 switch (termios->c_cflag & CSIZE) {
361 lcr_h = UART01x_LCRH_WLEN_5;
364 lcr_h = UART01x_LCRH_WLEN_6;
367 lcr_h = UART01x_LCRH_WLEN_7;
370 lcr_h = UART01x_LCRH_WLEN_8;
373 if (termios->c_cflag & CSTOPB)
374 lcr_h |= UART01x_LCRH_STP2;
375 if (termios->c_cflag & PARENB) {
376 lcr_h |= UART01x_LCRH_PEN;
377 if (!(termios->c_cflag & PARODD))
378 lcr_h |= UART01x_LCRH_EPS;
380 if (port->fifosize > 1)
381 lcr_h |= UART01x_LCRH_FEN;
383 spin_lock_irqsave(&port->lock, flags);
386 * Update the per-port timeout.
388 uart_update_timeout(port, termios->c_cflag, baud);
390 port->read_status_mask = UART01x_RSR_OE;
391 if (termios->c_iflag & INPCK)
392 port->read_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
393 if (termios->c_iflag & (BRKINT | PARMRK))
394 port->read_status_mask |= UART01x_RSR_BE;
397 * Characters to ignore
399 port->ignore_status_mask = 0;
400 if (termios->c_iflag & IGNPAR)
401 port->ignore_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
402 if (termios->c_iflag & IGNBRK) {
403 port->ignore_status_mask |= UART01x_RSR_BE;
405 * If we're ignoring parity and break indicators,
406 * ignore overruns too (for real raw support).
408 if (termios->c_iflag & IGNPAR)
409 port->ignore_status_mask |= UART01x_RSR_OE;
413 * Ignore all characters if CREAD is not set.
415 if ((termios->c_cflag & CREAD) == 0)
416 port->ignore_status_mask |= UART_DUMMY_RSR_RX;
418 /* first, disable everything */
419 old_cr = readb(port->membase + UART010_CR) & ~UART010_CR_MSIE;
421 if (UART_ENABLE_MS(port, termios->c_cflag))
422 old_cr |= UART010_CR_MSIE;
424 writel(0, port->membase + UART010_CR);
428 writel((quot & 0xf00) >> 8, port->membase + UART010_LCRM);
429 writel(quot & 0xff, port->membase + UART010_LCRL);
432 * ----------v----------v----------v----------v-----
433 * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L
434 * ----------^----------^----------^----------^-----
436 writel(lcr_h, port->membase + UART010_LCRH);
437 writel(old_cr, port->membase + UART010_CR);
439 spin_unlock_irqrestore(&port->lock, flags);
442 static const char *pl010_type(struct uart_port *port)
444 return port->type == PORT_AMBA ? "AMBA" : NULL;
448 * Release the memory region(s) being used by 'port'
450 static void pl010_release_port(struct uart_port *port)
452 release_mem_region(port->mapbase, UART_PORT_SIZE);
456 * Request the memory region(s) being used by 'port'
458 static int pl010_request_port(struct uart_port *port)
460 return request_mem_region(port->mapbase, UART_PORT_SIZE, "uart-pl010")
461 != NULL ? 0 : -EBUSY;
465 * Configure/autoconfigure the port.
467 static void pl010_config_port(struct uart_port *port, int flags)
469 if (flags & UART_CONFIG_TYPE) {
470 port->type = PORT_AMBA;
471 pl010_request_port(port);
476 * verify the new serial_struct (for TIOCSSERIAL).
478 static int pl010_verify_port(struct uart_port *port, struct serial_struct *ser)
481 if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA)
483 if (ser->irq < 0 || ser->irq >= NR_IRQS)
485 if (ser->baud_base < 9600)
490 static struct uart_ops amba_pl010_pops = {
491 .tx_empty = pl010_tx_empty,
492 .set_mctrl = pl010_set_mctrl,
493 .get_mctrl = pl010_get_mctrl,
494 .stop_tx = pl010_stop_tx,
495 .start_tx = pl010_start_tx,
496 .stop_rx = pl010_stop_rx,
497 .enable_ms = pl010_enable_ms,
498 .break_ctl = pl010_break_ctl,
499 .startup = pl010_startup,
500 .shutdown = pl010_shutdown,
501 .set_termios = pl010_set_termios,
503 .release_port = pl010_release_port,
504 .request_port = pl010_request_port,
505 .config_port = pl010_config_port,
506 .verify_port = pl010_verify_port,
509 static struct uart_amba_port *amba_ports[UART_NR];
511 #ifdef CONFIG_SERIAL_AMBA_PL010_CONSOLE
513 static void pl010_console_putchar(struct uart_port *port, int ch)
518 status = readb(port->membase + UART01x_FR);
520 } while (!UART_TX_READY(status));
521 writel(ch, port->membase + UART01x_DR);
525 pl010_console_write(struct console *co, const char *s, unsigned int count)
527 struct uart_port *port = &amba_ports[co->index]->port;
528 unsigned int status, old_cr;
531 * First save the CR then disable the interrupts
533 old_cr = readb(port->membase + UART010_CR);
534 writel(UART01x_CR_UARTEN, port->membase + UART010_CR);
536 uart_console_write(port, s, count, pl010_console_putchar);
539 * Finally, wait for transmitter to become empty
540 * and restore the TCR
543 status = readb(port->membase + UART01x_FR);
545 } while (status & UART01x_FR_BUSY);
546 writel(old_cr, port->membase + UART010_CR);
550 pl010_console_get_options(struct uart_port *port, int *baud,
551 int *parity, int *bits)
553 if (readb(port->membase + UART010_CR) & UART01x_CR_UARTEN) {
554 unsigned int lcr_h, quot;
555 lcr_h = readb(port->membase + UART010_LCRH);
558 if (lcr_h & UART01x_LCRH_PEN) {
559 if (lcr_h & UART01x_LCRH_EPS)
565 if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7)
570 quot = readb(port->membase + UART010_LCRL) | readb(port->membase + UART010_LCRM) << 8;
571 *baud = port->uartclk / (16 * (quot + 1));
575 static int __init pl010_console_setup(struct console *co, char *options)
577 struct uart_port *port;
584 * Check whether an invalid uart number has been specified, and
585 * if so, search for the first available port that does have
588 if (co->index >= UART_NR)
590 port = &amba_ports[co->index]->port;
593 uart_parse_options(options, &baud, &parity, &bits, &flow);
595 pl010_console_get_options(port, &baud, &parity, &bits);
597 return uart_set_options(port, co, baud, parity, bits, flow);
600 static struct uart_driver amba_reg;
601 static struct console amba_console = {
603 .write = pl010_console_write,
604 .device = uart_console_device,
605 .setup = pl010_console_setup,
606 .flags = CON_PRINTBUFFER,
611 #define AMBA_CONSOLE &amba_console
613 #define AMBA_CONSOLE NULL
616 static struct uart_driver amba_reg = {
617 .owner = THIS_MODULE,
618 .driver_name = "ttyAM",
620 .major = SERIAL_AMBA_MAJOR,
621 .minor = SERIAL_AMBA_MINOR,
623 .cons = AMBA_CONSOLE,
626 static int pl010_probe(struct amba_device *dev, void *id)
628 struct uart_amba_port *port;
632 for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
633 if (amba_ports[i] == NULL)
636 if (i == ARRAY_SIZE(amba_ports)) {
641 port = kzalloc(sizeof(struct uart_amba_port), GFP_KERNEL);
647 base = ioremap(dev->res.start, PAGE_SIZE);
653 port->port.dev = &dev->dev;
654 port->port.mapbase = dev->res.start;
655 port->port.membase = base;
656 port->port.iotype = UPIO_MEM;
657 port->port.irq = dev->irq[0];
658 port->port.uartclk = 14745600;
659 port->port.fifosize = 16;
660 port->port.ops = &amba_pl010_pops;
661 port->port.flags = UPF_BOOT_AUTOCONF;
664 port->data = dev->dev.platform_data;
666 amba_ports[i] = port;
668 amba_set_drvdata(dev, port);
669 ret = uart_add_one_port(&amba_reg, &port->port);
671 amba_set_drvdata(dev, NULL);
672 amba_ports[i] = NULL;
682 static int pl010_remove(struct amba_device *dev)
684 struct uart_amba_port *port = amba_get_drvdata(dev);
687 amba_set_drvdata(dev, NULL);
689 uart_remove_one_port(&amba_reg, &port->port);
691 for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
692 if (amba_ports[i] == port)
693 amba_ports[i] = NULL;
695 iounmap(port->port.membase);
701 static int pl010_suspend(struct amba_device *dev, pm_message_t state)
703 struct uart_amba_port *uap = amba_get_drvdata(dev);
706 uart_suspend_port(&amba_reg, &uap->port);
711 static int pl010_resume(struct amba_device *dev)
713 struct uart_amba_port *uap = amba_get_drvdata(dev);
716 uart_resume_port(&amba_reg, &uap->port);
721 static struct amba_id pl010_ids[] __initdata = {
729 static struct amba_driver pl010_driver = {
731 .name = "uart-pl010",
733 .id_table = pl010_ids,
734 .probe = pl010_probe,
735 .remove = pl010_remove,
736 .suspend = pl010_suspend,
737 .resume = pl010_resume,
740 static int __init pl010_init(void)
744 printk(KERN_INFO "Serial: AMBA driver $Revision: 1.41 $\n");
746 ret = uart_register_driver(&amba_reg);
748 ret = amba_driver_register(&pl010_driver);
750 uart_unregister_driver(&amba_reg);
755 static void __exit pl010_exit(void)
757 amba_driver_unregister(&pl010_driver);
758 uart_unregister_driver(&amba_reg);
761 module_init(pl010_init);
762 module_exit(pl010_exit);
764 MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
765 MODULE_DESCRIPTION("ARM AMBA serial port driver $Revision: 1.41 $");
766 MODULE_LICENSE("GPL");