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.
34 #include <linux/config.h>
36 #if defined(CONFIG_SERIAL_AMBA_PL010_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
40 #include <linux/module.h>
41 #include <linux/ioport.h>
42 #include <linux/init.h>
43 #include <linux/console.h>
44 #include <linux/sysrq.h>
45 #include <linux/device.h>
46 #include <linux/tty.h>
47 #include <linux/tty_flip.h>
48 #include <linux/serial_core.h>
49 #include <linux/serial.h>
53 #include <asm/hardware/amba.h>
54 #include <asm/hardware/amba_serial.h>
58 #define SERIAL_AMBA_MAJOR 204
59 #define SERIAL_AMBA_MINOR 16
60 #define SERIAL_AMBA_NR UART_NR
62 #define AMBA_ISR_PASS_LIMIT 256
65 * Access macros for the AMBA UARTs
67 #define UART_GET_INT_STATUS(p) readb((p)->membase + UART010_IIR)
68 #define UART_PUT_ICR(p, c) writel((c), (p)->membase + UART010_ICR)
69 #define UART_GET_FR(p) readb((p)->membase + UART01x_FR)
70 #define UART_GET_CHAR(p) readb((p)->membase + UART01x_DR)
71 #define UART_PUT_CHAR(p, c) writel((c), (p)->membase + UART01x_DR)
72 #define UART_GET_RSR(p) readb((p)->membase + UART01x_RSR)
73 #define UART_GET_CR(p) readb((p)->membase + UART010_CR)
74 #define UART_PUT_CR(p,c) writel((c), (p)->membase + UART010_CR)
75 #define UART_GET_LCRL(p) readb((p)->membase + UART010_LCRL)
76 #define UART_PUT_LCRL(p,c) writel((c), (p)->membase + UART010_LCRL)
77 #define UART_GET_LCRM(p) readb((p)->membase + UART010_LCRM)
78 #define UART_PUT_LCRM(p,c) writel((c), (p)->membase + UART010_LCRM)
79 #define UART_GET_LCRH(p) readb((p)->membase + UART010_LCRH)
80 #define UART_PUT_LCRH(p,c) writel((c), (p)->membase + UART010_LCRH)
81 #define UART_RX_DATA(s) (((s) & UART01x_FR_RXFE) == 0)
82 #define UART_TX_READY(s) (((s) & UART01x_FR_TXFF) == 0)
83 #define UART_TX_EMPTY(p) ((UART_GET_FR(p) & UART01x_FR_TMSK) == 0)
85 #define UART_DUMMY_RSR_RX /*256*/0
86 #define UART_PORT_SIZE 64
89 * On the Integrator platform, the port RTS and DTR are provided by
90 * bits in the following SC_CTRLS register bits:
95 #define SC_CTRLC (IO_ADDRESS(INTEGRATOR_SC_BASE) + INTEGRATOR_SC_CTRLC_OFFSET)
96 #define SC_CTRLS (IO_ADDRESS(INTEGRATOR_SC_BASE) + INTEGRATOR_SC_CTRLS_OFFSET)
99 * We wrap our port structure around the generic uart_port.
101 struct uart_amba_port
{
102 struct uart_port port
;
103 unsigned int dtr_mask
;
104 unsigned int rts_mask
;
105 unsigned int old_status
;
108 static void pl010_stop_tx(struct uart_port
*port
, unsigned int tty_stop
)
112 cr
= UART_GET_CR(port
);
113 cr
&= ~UART010_CR_TIE
;
114 UART_PUT_CR(port
, cr
);
117 static void pl010_start_tx(struct uart_port
*port
, unsigned int tty_start
)
121 cr
= UART_GET_CR(port
);
122 cr
|= UART010_CR_TIE
;
123 UART_PUT_CR(port
, cr
);
126 static void pl010_stop_rx(struct uart_port
*port
)
130 cr
= UART_GET_CR(port
);
131 cr
&= ~(UART010_CR_RIE
| UART010_CR_RTIE
);
132 UART_PUT_CR(port
, cr
);
135 static void pl010_enable_ms(struct uart_port
*port
)
139 cr
= UART_GET_CR(port
);
140 cr
|= UART010_CR_MSIE
;
141 UART_PUT_CR(port
, cr
);
146 pl010_rx_chars(struct uart_port
*port
, struct pt_regs
*regs
)
148 pl010_rx_chars(struct uart_port
*port
)
151 struct tty_struct
*tty
= port
->info
->tty
;
152 unsigned int status
, ch
, flag
, rsr
, max_count
= 256;
154 status
= UART_GET_FR(port
);
155 while (UART_RX_DATA(status
) && max_count
--) {
156 if (tty
->flip
.count
>= TTY_FLIPBUF_SIZE
) {
157 if (tty
->low_latency
)
158 tty_flip_buffer_push(tty
);
160 * If this failed then we will throw away the
161 * bytes but must do so to clear interrupts.
165 ch
= UART_GET_CHAR(port
);
171 * Note that the error handling code is
172 * out of the main execution path
174 rsr
= UART_GET_RSR(port
) | UART_DUMMY_RSR_RX
;
175 if (unlikely(rsr
& UART01x_RSR_ANY
)) {
176 if (rsr
& UART01x_RSR_BE
) {
177 rsr
&= ~(UART01x_RSR_FE
| UART01x_RSR_PE
);
179 if (uart_handle_break(port
))
181 } else if (rsr
& UART01x_RSR_PE
)
182 port
->icount
.parity
++;
183 else if (rsr
& UART01x_RSR_FE
)
184 port
->icount
.frame
++;
185 if (rsr
& UART01x_RSR_OE
)
186 port
->icount
.overrun
++;
188 rsr
&= port
->read_status_mask
;
190 if (rsr
& UART01x_RSR_BE
)
192 else if (rsr
& UART01x_RSR_PE
)
194 else if (rsr
& UART01x_RSR_FE
)
198 if (uart_handle_sysrq_char(port
, ch
, regs
))
201 uart_insert_char(port
, rsr
, UART01x_RSR_OE
, ch
, flag
);
204 status
= UART_GET_FR(port
);
206 tty_flip_buffer_push(tty
);
210 static void pl010_tx_chars(struct uart_port
*port
)
212 struct circ_buf
*xmit
= &port
->info
->xmit
;
216 UART_PUT_CHAR(port
, port
->x_char
);
221 if (uart_circ_empty(xmit
) || uart_tx_stopped(port
)) {
222 pl010_stop_tx(port
, 0);
226 count
= port
->fifosize
>> 1;
228 UART_PUT_CHAR(port
, xmit
->buf
[xmit
->tail
]);
229 xmit
->tail
= (xmit
->tail
+ 1) & (UART_XMIT_SIZE
- 1);
231 if (uart_circ_empty(xmit
))
233 } while (--count
> 0);
235 if (uart_circ_chars_pending(xmit
) < WAKEUP_CHARS
)
236 uart_write_wakeup(port
);
238 if (uart_circ_empty(xmit
))
239 pl010_stop_tx(port
, 0);
242 static void pl010_modem_status(struct uart_port
*port
)
244 struct uart_amba_port
*uap
= (struct uart_amba_port
*)port
;
245 unsigned int status
, delta
;
247 UART_PUT_ICR(&uap
->port
, 0);
249 status
= UART_GET_FR(&uap
->port
) & UART01x_FR_MODEM_ANY
;
251 delta
= status
^ uap
->old_status
;
252 uap
->old_status
= status
;
257 if (delta
& UART01x_FR_DCD
)
258 uart_handle_dcd_change(&uap
->port
, status
& UART01x_FR_DCD
);
260 if (delta
& UART01x_FR_DSR
)
261 uap
->port
.icount
.dsr
++;
263 if (delta
& UART01x_FR_CTS
)
264 uart_handle_cts_change(&uap
->port
, status
& UART01x_FR_CTS
);
266 wake_up_interruptible(&uap
->port
.info
->delta_msr_wait
);
269 static irqreturn_t
pl010_int(int irq
, void *dev_id
, struct pt_regs
*regs
)
271 struct uart_port
*port
= dev_id
;
272 unsigned int status
, pass_counter
= AMBA_ISR_PASS_LIMIT
;
275 spin_lock(&port
->lock
);
277 status
= UART_GET_INT_STATUS(port
);
280 if (status
& (UART010_IIR_RTIS
| UART010_IIR_RIS
))
282 pl010_rx_chars(port
, regs
);
284 pl010_rx_chars(port
);
286 if (status
& UART010_IIR_MIS
)
287 pl010_modem_status(port
);
288 if (status
& UART010_IIR_TIS
)
289 pl010_tx_chars(port
);
291 if (pass_counter
-- == 0)
294 status
= UART_GET_INT_STATUS(port
);
295 } while (status
& (UART010_IIR_RTIS
| UART010_IIR_RIS
|
300 spin_unlock(&port
->lock
);
302 return IRQ_RETVAL(handled
);
305 static unsigned int pl010_tx_empty(struct uart_port
*port
)
307 return UART_GET_FR(port
) & UART01x_FR_BUSY
? 0 : TIOCSER_TEMT
;
310 static unsigned int pl010_get_mctrl(struct uart_port
*port
)
312 unsigned int result
= 0;
315 status
= UART_GET_FR(port
);
316 if (status
& UART01x_FR_DCD
)
318 if (status
& UART01x_FR_DSR
)
320 if (status
& UART01x_FR_CTS
)
326 static void pl010_set_mctrl(struct uart_port
*port
, unsigned int mctrl
)
328 struct uart_amba_port
*uap
= (struct uart_amba_port
*)port
;
329 unsigned int ctrls
= 0, ctrlc
= 0;
331 if (mctrl
& TIOCM_RTS
)
332 ctrlc
|= uap
->rts_mask
;
334 ctrls
|= uap
->rts_mask
;
336 if (mctrl
& TIOCM_DTR
)
337 ctrlc
|= uap
->dtr_mask
;
339 ctrls
|= uap
->dtr_mask
;
341 __raw_writel(ctrls
, SC_CTRLS
);
342 __raw_writel(ctrlc
, SC_CTRLC
);
345 static void pl010_break_ctl(struct uart_port
*port
, int break_state
)
350 spin_lock_irqsave(&port
->lock
, flags
);
351 lcr_h
= UART_GET_LCRH(port
);
352 if (break_state
== -1)
353 lcr_h
|= UART01x_LCRH_BRK
;
355 lcr_h
&= ~UART01x_LCRH_BRK
;
356 UART_PUT_LCRH(port
, lcr_h
);
357 spin_unlock_irqrestore(&port
->lock
, flags
);
360 static int pl010_startup(struct uart_port
*port
)
362 struct uart_amba_port
*uap
= (struct uart_amba_port
*)port
;
368 retval
= request_irq(port
->irq
, pl010_int
, 0, "uart-pl010", port
);
373 * initialise the old status of the modem signals
375 uap
->old_status
= UART_GET_FR(port
) & UART01x_FR_MODEM_ANY
;
378 * Finally, enable interrupts
380 UART_PUT_CR(port
, UART01x_CR_UARTEN
| UART010_CR_RIE
|
386 static void pl010_shutdown(struct uart_port
*port
)
391 free_irq(port
->irq
, port
);
394 * disable all interrupts, disable the port
396 UART_PUT_CR(port
, 0);
398 /* disable break condition and fifos */
399 UART_PUT_LCRH(port
, UART_GET_LCRH(port
) &
400 ~(UART01x_LCRH_BRK
| UART01x_LCRH_FEN
));
404 pl010_set_termios(struct uart_port
*port
, struct termios
*termios
,
407 unsigned int lcr_h
, old_cr
;
409 unsigned int baud
, quot
;
412 * Ask the core to calculate the divisor for us.
414 baud
= uart_get_baud_rate(port
, termios
, old
, 0, port
->uartclk
/16);
415 quot
= uart_get_divisor(port
, baud
);
417 switch (termios
->c_cflag
& CSIZE
) {
419 lcr_h
= UART01x_LCRH_WLEN_5
;
422 lcr_h
= UART01x_LCRH_WLEN_6
;
425 lcr_h
= UART01x_LCRH_WLEN_7
;
428 lcr_h
= UART01x_LCRH_WLEN_8
;
431 if (termios
->c_cflag
& CSTOPB
)
432 lcr_h
|= UART01x_LCRH_STP2
;
433 if (termios
->c_cflag
& PARENB
) {
434 lcr_h
|= UART01x_LCRH_PEN
;
435 if (!(termios
->c_cflag
& PARODD
))
436 lcr_h
|= UART01x_LCRH_EPS
;
438 if (port
->fifosize
> 1)
439 lcr_h
|= UART01x_LCRH_FEN
;
441 spin_lock_irqsave(&port
->lock
, flags
);
444 * Update the per-port timeout.
446 uart_update_timeout(port
, termios
->c_cflag
, baud
);
448 port
->read_status_mask
= UART01x_RSR_OE
;
449 if (termios
->c_iflag
& INPCK
)
450 port
->read_status_mask
|= UART01x_RSR_FE
| UART01x_RSR_PE
;
451 if (termios
->c_iflag
& (BRKINT
| PARMRK
))
452 port
->read_status_mask
|= UART01x_RSR_BE
;
455 * Characters to ignore
457 port
->ignore_status_mask
= 0;
458 if (termios
->c_iflag
& IGNPAR
)
459 port
->ignore_status_mask
|= UART01x_RSR_FE
| UART01x_RSR_PE
;
460 if (termios
->c_iflag
& IGNBRK
) {
461 port
->ignore_status_mask
|= UART01x_RSR_BE
;
463 * If we're ignoring parity and break indicators,
464 * ignore overruns too (for real raw support).
466 if (termios
->c_iflag
& IGNPAR
)
467 port
->ignore_status_mask
|= UART01x_RSR_OE
;
471 * Ignore all characters if CREAD is not set.
473 if ((termios
->c_cflag
& CREAD
) == 0)
474 port
->ignore_status_mask
|= UART_DUMMY_RSR_RX
;
476 /* first, disable everything */
477 old_cr
= UART_GET_CR(port
) & ~UART010_CR_MSIE
;
479 if (UART_ENABLE_MS(port
, termios
->c_cflag
))
480 old_cr
|= UART010_CR_MSIE
;
482 UART_PUT_CR(port
, 0);
486 UART_PUT_LCRM(port
, ((quot
& 0xf00) >> 8));
487 UART_PUT_LCRL(port
, (quot
& 0xff));
490 * ----------v----------v----------v----------v-----
491 * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L
492 * ----------^----------^----------^----------^-----
494 UART_PUT_LCRH(port
, lcr_h
);
495 UART_PUT_CR(port
, old_cr
);
497 spin_unlock_irqrestore(&port
->lock
, flags
);
500 static const char *pl010_type(struct uart_port
*port
)
502 return port
->type
== PORT_AMBA
? "AMBA" : NULL
;
506 * Release the memory region(s) being used by 'port'
508 static void pl010_release_port(struct uart_port
*port
)
510 release_mem_region(port
->mapbase
, UART_PORT_SIZE
);
514 * Request the memory region(s) being used by 'port'
516 static int pl010_request_port(struct uart_port
*port
)
518 return request_mem_region(port
->mapbase
, UART_PORT_SIZE
, "uart-pl010")
519 != NULL
? 0 : -EBUSY
;
523 * Configure/autoconfigure the port.
525 static void pl010_config_port(struct uart_port
*port
, int flags
)
527 if (flags
& UART_CONFIG_TYPE
) {
528 port
->type
= PORT_AMBA
;
529 pl010_request_port(port
);
534 * verify the new serial_struct (for TIOCSSERIAL).
536 static int pl010_verify_port(struct uart_port
*port
, struct serial_struct
*ser
)
539 if (ser
->type
!= PORT_UNKNOWN
&& ser
->type
!= PORT_AMBA
)
541 if (ser
->irq
< 0 || ser
->irq
>= NR_IRQS
)
543 if (ser
->baud_base
< 9600)
548 static struct uart_ops amba_pl010_pops
= {
549 .tx_empty
= pl010_tx_empty
,
550 .set_mctrl
= pl010_set_mctrl
,
551 .get_mctrl
= pl010_get_mctrl
,
552 .stop_tx
= pl010_stop_tx
,
553 .start_tx
= pl010_start_tx
,
554 .stop_rx
= pl010_stop_rx
,
555 .enable_ms
= pl010_enable_ms
,
556 .break_ctl
= pl010_break_ctl
,
557 .startup
= pl010_startup
,
558 .shutdown
= pl010_shutdown
,
559 .set_termios
= pl010_set_termios
,
561 .release_port
= pl010_release_port
,
562 .request_port
= pl010_request_port
,
563 .config_port
= pl010_config_port
,
564 .verify_port
= pl010_verify_port
,
567 static struct uart_amba_port amba_ports
[UART_NR
] = {
570 .membase
= (void *)IO_ADDRESS(INTEGRATOR_UART0_BASE
),
571 .mapbase
= INTEGRATOR_UART0_BASE
,
572 .iotype
= SERIAL_IO_MEM
,
576 .ops
= &amba_pl010_pops
,
577 .flags
= ASYNC_BOOT_AUTOCONF
,
585 .membase
= (void *)IO_ADDRESS(INTEGRATOR_UART1_BASE
),
586 .mapbase
= INTEGRATOR_UART1_BASE
,
587 .iotype
= SERIAL_IO_MEM
,
591 .ops
= &amba_pl010_pops
,
592 .flags
= ASYNC_BOOT_AUTOCONF
,
600 #ifdef CONFIG_SERIAL_AMBA_PL010_CONSOLE
603 pl010_console_write(struct console
*co
, const char *s
, unsigned int count
)
605 struct uart_port
*port
= &amba_ports
[co
->index
].port
;
606 unsigned int status
, old_cr
;
610 * First save the CR then disable the interrupts
612 old_cr
= UART_GET_CR(port
);
613 UART_PUT_CR(port
, UART01x_CR_UARTEN
);
616 * Now, do each character
618 for (i
= 0; i
< count
; i
++) {
620 status
= UART_GET_FR(port
);
621 } while (!UART_TX_READY(status
));
622 UART_PUT_CHAR(port
, s
[i
]);
625 status
= UART_GET_FR(port
);
626 } while (!UART_TX_READY(status
));
627 UART_PUT_CHAR(port
, '\r');
632 * Finally, wait for transmitter to become empty
633 * and restore the TCR
636 status
= UART_GET_FR(port
);
637 } while (status
& UART01x_FR_BUSY
);
638 UART_PUT_CR(port
, old_cr
);
642 pl010_console_get_options(struct uart_port
*port
, int *baud
,
643 int *parity
, int *bits
)
645 if (UART_GET_CR(port
) & UART01x_CR_UARTEN
) {
646 unsigned int lcr_h
, quot
;
647 lcr_h
= UART_GET_LCRH(port
);
650 if (lcr_h
& UART01x_LCRH_PEN
) {
651 if (lcr_h
& UART01x_LCRH_EPS
)
657 if ((lcr_h
& 0x60) == UART01x_LCRH_WLEN_7
)
662 quot
= UART_GET_LCRL(port
) | UART_GET_LCRM(port
) << 8;
663 *baud
= port
->uartclk
/ (16 * (quot
+ 1));
667 static int __init
pl010_console_setup(struct console
*co
, char *options
)
669 struct uart_port
*port
;
676 * Check whether an invalid uart number has been specified, and
677 * if so, search for the first available port that does have
680 if (co
->index
>= UART_NR
)
682 port
= &amba_ports
[co
->index
].port
;
685 uart_parse_options(options
, &baud
, &parity
, &bits
, &flow
);
687 pl010_console_get_options(port
, &baud
, &parity
, &bits
);
689 return uart_set_options(port
, co
, baud
, parity
, bits
, flow
);
692 extern struct uart_driver amba_reg
;
693 static struct console amba_console
= {
695 .write
= pl010_console_write
,
696 .device
= uart_console_device
,
697 .setup
= pl010_console_setup
,
698 .flags
= CON_PRINTBUFFER
,
703 static int __init
amba_console_init(void)
706 * All port initializations are done statically
708 register_console(&amba_console
);
711 console_initcall(amba_console_init
);
713 static int __init
amba_late_console_init(void)
715 if (!(amba_console
.flags
& CON_ENABLED
))
716 register_console(&amba_console
);
719 late_initcall(amba_late_console_init
);
721 #define AMBA_CONSOLE &amba_console
723 #define AMBA_CONSOLE NULL
726 static struct uart_driver amba_reg
= {
727 .owner
= THIS_MODULE
,
728 .driver_name
= "ttyAM",
730 .major
= SERIAL_AMBA_MAJOR
,
731 .minor
= SERIAL_AMBA_MINOR
,
733 .cons
= AMBA_CONSOLE
,
736 static int pl010_probe(struct amba_device
*dev
, void *id
)
740 for (i
= 0; i
< UART_NR
; i
++) {
741 if (amba_ports
[i
].port
.mapbase
!= dev
->res
.start
)
744 amba_ports
[i
].port
.dev
= &dev
->dev
;
745 uart_add_one_port(&amba_reg
, &amba_ports
[i
].port
);
746 amba_set_drvdata(dev
, &amba_ports
[i
]);
753 static int pl010_remove(struct amba_device
*dev
)
755 struct uart_amba_port
*uap
= amba_get_drvdata(dev
);
758 uart_remove_one_port(&amba_reg
, &uap
->port
);
760 amba_set_drvdata(dev
, NULL
);
765 static int pl010_suspend(struct amba_device
*dev
, pm_message_t state
)
767 struct uart_amba_port
*uap
= amba_get_drvdata(dev
);
770 uart_suspend_port(&amba_reg
, &uap
->port
);
775 static int pl010_resume(struct amba_device
*dev
)
777 struct uart_amba_port
*uap
= amba_get_drvdata(dev
);
780 uart_resume_port(&amba_reg
, &uap
->port
);
785 static struct amba_id pl010_ids
[] __initdata
= {
793 static struct amba_driver pl010_driver
= {
795 .name
= "uart-pl010",
797 .id_table
= pl010_ids
,
798 .probe
= pl010_probe
,
799 .remove
= pl010_remove
,
800 .suspend
= pl010_suspend
,
801 .resume
= pl010_resume
,
804 static int __init
pl010_init(void)
808 printk(KERN_INFO
"Serial: AMBA driver $Revision: 1.41 $\n");
810 ret
= uart_register_driver(&amba_reg
);
812 ret
= amba_driver_register(&pl010_driver
);
814 uart_unregister_driver(&amba_reg
);
819 static void __exit
pl010_exit(void)
821 amba_driver_unregister(&pl010_driver
);
822 uart_unregister_driver(&amba_reg
);
825 module_init(pl010_init
);
826 module_exit(pl010_exit
);
828 MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
829 MODULE_DESCRIPTION("ARM AMBA serial port driver $Revision: 1.41 $");
830 MODULE_LICENSE("GPL");