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 writel(0, port
->membase
+ UART01x_ECR
);
134 if (rsr
& UART01x_RSR_BE
) {
135 rsr
&= ~(UART01x_RSR_FE
| UART01x_RSR_PE
);
137 if (uart_handle_break(port
))
139 } else if (rsr
& UART01x_RSR_PE
)
140 port
->icount
.parity
++;
141 else if (rsr
& UART01x_RSR_FE
)
142 port
->icount
.frame
++;
143 if (rsr
& UART01x_RSR_OE
)
144 port
->icount
.overrun
++;
146 rsr
&= port
->read_status_mask
;
148 if (rsr
& UART01x_RSR_BE
)
150 else if (rsr
& UART01x_RSR_PE
)
152 else if (rsr
& UART01x_RSR_FE
)
156 if (uart_handle_sysrq_char(port
, ch
))
159 uart_insert_char(port
, rsr
, UART01x_RSR_OE
, ch
, flag
);
162 status
= readb(port
->membase
+ UART01x_FR
);
164 tty_flip_buffer_push(tty
);
168 static void pl010_tx_chars(struct uart_port
*port
)
170 struct circ_buf
*xmit
= &port
->info
->xmit
;
174 writel(port
->x_char
, port
->membase
+ UART01x_DR
);
179 if (uart_circ_empty(xmit
) || uart_tx_stopped(port
)) {
184 count
= port
->fifosize
>> 1;
186 writel(xmit
->buf
[xmit
->tail
], port
->membase
+ UART01x_DR
);
187 xmit
->tail
= (xmit
->tail
+ 1) & (UART_XMIT_SIZE
- 1);
189 if (uart_circ_empty(xmit
))
191 } while (--count
> 0);
193 if (uart_circ_chars_pending(xmit
) < WAKEUP_CHARS
)
194 uart_write_wakeup(port
);
196 if (uart_circ_empty(xmit
))
200 static void pl010_modem_status(struct uart_port
*port
)
202 struct uart_amba_port
*uap
= (struct uart_amba_port
*)port
;
203 unsigned int status
, delta
;
205 writel(0, uap
->port
.membase
+ UART010_ICR
);
207 status
= readb(uap
->port
.membase
+ UART01x_FR
) & UART01x_FR_MODEM_ANY
;
209 delta
= status
^ uap
->old_status
;
210 uap
->old_status
= status
;
215 if (delta
& UART01x_FR_DCD
)
216 uart_handle_dcd_change(&uap
->port
, status
& UART01x_FR_DCD
);
218 if (delta
& UART01x_FR_DSR
)
219 uap
->port
.icount
.dsr
++;
221 if (delta
& UART01x_FR_CTS
)
222 uart_handle_cts_change(&uap
->port
, status
& UART01x_FR_CTS
);
224 wake_up_interruptible(&uap
->port
.info
->delta_msr_wait
);
227 static irqreturn_t
pl010_int(int irq
, void *dev_id
)
229 struct uart_port
*port
= dev_id
;
230 unsigned int status
, pass_counter
= AMBA_ISR_PASS_LIMIT
;
233 spin_lock(&port
->lock
);
235 status
= readb(port
->membase
+ UART010_IIR
);
238 if (status
& (UART010_IIR_RTIS
| UART010_IIR_RIS
))
239 pl010_rx_chars(port
);
240 if (status
& UART010_IIR_MIS
)
241 pl010_modem_status(port
);
242 if (status
& UART010_IIR_TIS
)
243 pl010_tx_chars(port
);
245 if (pass_counter
-- == 0)
248 status
= readb(port
->membase
+ UART010_IIR
);
249 } while (status
& (UART010_IIR_RTIS
| UART010_IIR_RIS
|
254 spin_unlock(&port
->lock
);
256 return IRQ_RETVAL(handled
);
259 static unsigned int pl010_tx_empty(struct uart_port
*port
)
261 return readb(port
->membase
+ UART01x_FR
) & UART01x_FR_BUSY
? 0 : TIOCSER_TEMT
;
264 static unsigned int pl010_get_mctrl(struct uart_port
*port
)
266 unsigned int result
= 0;
269 status
= readb(port
->membase
+ UART01x_FR
);
270 if (status
& UART01x_FR_DCD
)
272 if (status
& UART01x_FR_DSR
)
274 if (status
& UART01x_FR_CTS
)
280 static void pl010_set_mctrl(struct uart_port
*port
, unsigned int mctrl
)
282 struct uart_amba_port
*uap
= (struct uart_amba_port
*)port
;
285 uap
->data
->set_mctrl(uap
->dev
, uap
->port
.membase
, mctrl
);
288 static void pl010_break_ctl(struct uart_port
*port
, int break_state
)
293 spin_lock_irqsave(&port
->lock
, flags
);
294 lcr_h
= readb(port
->membase
+ UART010_LCRH
);
295 if (break_state
== -1)
296 lcr_h
|= UART01x_LCRH_BRK
;
298 lcr_h
&= ~UART01x_LCRH_BRK
;
299 writel(lcr_h
, port
->membase
+ UART010_LCRH
);
300 spin_unlock_irqrestore(&port
->lock
, flags
);
303 static int pl010_startup(struct uart_port
*port
)
305 struct uart_amba_port
*uap
= (struct uart_amba_port
*)port
;
311 retval
= request_irq(port
->irq
, pl010_int
, 0, "uart-pl010", port
);
316 * initialise the old status of the modem signals
318 uap
->old_status
= readb(port
->membase
+ UART01x_FR
) & UART01x_FR_MODEM_ANY
;
321 * Finally, enable interrupts
323 writel(UART01x_CR_UARTEN
| UART010_CR_RIE
| UART010_CR_RTIE
,
324 port
->membase
+ UART010_CR
);
329 static void pl010_shutdown(struct uart_port
*port
)
334 free_irq(port
->irq
, port
);
337 * disable all interrupts, disable the port
339 writel(0, port
->membase
+ UART010_CR
);
341 /* disable break condition and fifos */
342 writel(readb(port
->membase
+ UART010_LCRH
) &
343 ~(UART01x_LCRH_BRK
| UART01x_LCRH_FEN
),
344 port
->membase
+ UART010_LCRH
);
348 pl010_set_termios(struct uart_port
*port
, struct ktermios
*termios
,
349 struct ktermios
*old
)
351 unsigned int lcr_h
, old_cr
;
353 unsigned int baud
, quot
;
356 * Ask the core to calculate the divisor for us.
358 baud
= uart_get_baud_rate(port
, termios
, old
, 0, port
->uartclk
/16);
359 quot
= uart_get_divisor(port
, baud
);
361 switch (termios
->c_cflag
& CSIZE
) {
363 lcr_h
= UART01x_LCRH_WLEN_5
;
366 lcr_h
= UART01x_LCRH_WLEN_6
;
369 lcr_h
= UART01x_LCRH_WLEN_7
;
372 lcr_h
= UART01x_LCRH_WLEN_8
;
375 if (termios
->c_cflag
& CSTOPB
)
376 lcr_h
|= UART01x_LCRH_STP2
;
377 if (termios
->c_cflag
& PARENB
) {
378 lcr_h
|= UART01x_LCRH_PEN
;
379 if (!(termios
->c_cflag
& PARODD
))
380 lcr_h
|= UART01x_LCRH_EPS
;
382 if (port
->fifosize
> 1)
383 lcr_h
|= UART01x_LCRH_FEN
;
385 spin_lock_irqsave(&port
->lock
, flags
);
388 * Update the per-port timeout.
390 uart_update_timeout(port
, termios
->c_cflag
, baud
);
392 port
->read_status_mask
= UART01x_RSR_OE
;
393 if (termios
->c_iflag
& INPCK
)
394 port
->read_status_mask
|= UART01x_RSR_FE
| UART01x_RSR_PE
;
395 if (termios
->c_iflag
& (BRKINT
| PARMRK
))
396 port
->read_status_mask
|= UART01x_RSR_BE
;
399 * Characters to ignore
401 port
->ignore_status_mask
= 0;
402 if (termios
->c_iflag
& IGNPAR
)
403 port
->ignore_status_mask
|= UART01x_RSR_FE
| UART01x_RSR_PE
;
404 if (termios
->c_iflag
& IGNBRK
) {
405 port
->ignore_status_mask
|= UART01x_RSR_BE
;
407 * If we're ignoring parity and break indicators,
408 * ignore overruns too (for real raw support).
410 if (termios
->c_iflag
& IGNPAR
)
411 port
->ignore_status_mask
|= UART01x_RSR_OE
;
415 * Ignore all characters if CREAD is not set.
417 if ((termios
->c_cflag
& CREAD
) == 0)
418 port
->ignore_status_mask
|= UART_DUMMY_RSR_RX
;
420 /* first, disable everything */
421 old_cr
= readb(port
->membase
+ UART010_CR
) & ~UART010_CR_MSIE
;
423 if (UART_ENABLE_MS(port
, termios
->c_cflag
))
424 old_cr
|= UART010_CR_MSIE
;
426 writel(0, port
->membase
+ UART010_CR
);
430 writel((quot
& 0xf00) >> 8, port
->membase
+ UART010_LCRM
);
431 writel(quot
& 0xff, port
->membase
+ UART010_LCRL
);
434 * ----------v----------v----------v----------v-----
435 * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L
436 * ----------^----------^----------^----------^-----
438 writel(lcr_h
, port
->membase
+ UART010_LCRH
);
439 writel(old_cr
, port
->membase
+ UART010_CR
);
441 spin_unlock_irqrestore(&port
->lock
, flags
);
444 static const char *pl010_type(struct uart_port
*port
)
446 return port
->type
== PORT_AMBA
? "AMBA" : NULL
;
450 * Release the memory region(s) being used by 'port'
452 static void pl010_release_port(struct uart_port
*port
)
454 release_mem_region(port
->mapbase
, UART_PORT_SIZE
);
458 * Request the memory region(s) being used by 'port'
460 static int pl010_request_port(struct uart_port
*port
)
462 return request_mem_region(port
->mapbase
, UART_PORT_SIZE
, "uart-pl010")
463 != NULL
? 0 : -EBUSY
;
467 * Configure/autoconfigure the port.
469 static void pl010_config_port(struct uart_port
*port
, int flags
)
471 if (flags
& UART_CONFIG_TYPE
) {
472 port
->type
= PORT_AMBA
;
473 pl010_request_port(port
);
478 * verify the new serial_struct (for TIOCSSERIAL).
480 static int pl010_verify_port(struct uart_port
*port
, struct serial_struct
*ser
)
483 if (ser
->type
!= PORT_UNKNOWN
&& ser
->type
!= PORT_AMBA
)
485 if (ser
->irq
< 0 || ser
->irq
>= NR_IRQS
)
487 if (ser
->baud_base
< 9600)
492 static struct uart_ops amba_pl010_pops
= {
493 .tx_empty
= pl010_tx_empty
,
494 .set_mctrl
= pl010_set_mctrl
,
495 .get_mctrl
= pl010_get_mctrl
,
496 .stop_tx
= pl010_stop_tx
,
497 .start_tx
= pl010_start_tx
,
498 .stop_rx
= pl010_stop_rx
,
499 .enable_ms
= pl010_enable_ms
,
500 .break_ctl
= pl010_break_ctl
,
501 .startup
= pl010_startup
,
502 .shutdown
= pl010_shutdown
,
503 .set_termios
= pl010_set_termios
,
505 .release_port
= pl010_release_port
,
506 .request_port
= pl010_request_port
,
507 .config_port
= pl010_config_port
,
508 .verify_port
= pl010_verify_port
,
511 static struct uart_amba_port
*amba_ports
[UART_NR
];
513 #ifdef CONFIG_SERIAL_AMBA_PL010_CONSOLE
515 static void pl010_console_putchar(struct uart_port
*port
, int ch
)
520 status
= readb(port
->membase
+ UART01x_FR
);
522 } while (!UART_TX_READY(status
));
523 writel(ch
, port
->membase
+ UART01x_DR
);
527 pl010_console_write(struct console
*co
, const char *s
, unsigned int count
)
529 struct uart_port
*port
= &amba_ports
[co
->index
]->port
;
530 unsigned int status
, old_cr
;
533 * First save the CR then disable the interrupts
535 old_cr
= readb(port
->membase
+ UART010_CR
);
536 writel(UART01x_CR_UARTEN
, port
->membase
+ UART010_CR
);
538 uart_console_write(port
, s
, count
, pl010_console_putchar
);
541 * Finally, wait for transmitter to become empty
542 * and restore the TCR
545 status
= readb(port
->membase
+ UART01x_FR
);
547 } while (status
& UART01x_FR_BUSY
);
548 writel(old_cr
, port
->membase
+ UART010_CR
);
552 pl010_console_get_options(struct uart_port
*port
, int *baud
,
553 int *parity
, int *bits
)
555 if (readb(port
->membase
+ UART010_CR
) & UART01x_CR_UARTEN
) {
556 unsigned int lcr_h
, quot
;
557 lcr_h
= readb(port
->membase
+ UART010_LCRH
);
560 if (lcr_h
& UART01x_LCRH_PEN
) {
561 if (lcr_h
& UART01x_LCRH_EPS
)
567 if ((lcr_h
& 0x60) == UART01x_LCRH_WLEN_7
)
572 quot
= readb(port
->membase
+ UART010_LCRL
) | readb(port
->membase
+ UART010_LCRM
) << 8;
573 *baud
= port
->uartclk
/ (16 * (quot
+ 1));
577 static int __init
pl010_console_setup(struct console
*co
, char *options
)
579 struct uart_port
*port
;
586 * Check whether an invalid uart number has been specified, and
587 * if so, search for the first available port that does have
590 if (co
->index
>= UART_NR
)
592 if (!amba_ports
[co
->index
])
594 port
= &amba_ports
[co
->index
]->port
;
597 uart_parse_options(options
, &baud
, &parity
, &bits
, &flow
);
599 pl010_console_get_options(port
, &baud
, &parity
, &bits
);
601 return uart_set_options(port
, co
, baud
, parity
, bits
, flow
);
604 static struct uart_driver amba_reg
;
605 static struct console amba_console
= {
607 .write
= pl010_console_write
,
608 .device
= uart_console_device
,
609 .setup
= pl010_console_setup
,
610 .flags
= CON_PRINTBUFFER
,
615 #define AMBA_CONSOLE &amba_console
617 #define AMBA_CONSOLE NULL
620 static struct uart_driver amba_reg
= {
621 .owner
= THIS_MODULE
,
622 .driver_name
= "ttyAM",
624 .major
= SERIAL_AMBA_MAJOR
,
625 .minor
= SERIAL_AMBA_MINOR
,
627 .cons
= AMBA_CONSOLE
,
630 static int pl010_probe(struct amba_device
*dev
, void *id
)
632 struct uart_amba_port
*port
;
636 for (i
= 0; i
< ARRAY_SIZE(amba_ports
); i
++)
637 if (amba_ports
[i
] == NULL
)
640 if (i
== ARRAY_SIZE(amba_ports
)) {
645 port
= kzalloc(sizeof(struct uart_amba_port
), GFP_KERNEL
);
651 base
= ioremap(dev
->res
.start
, PAGE_SIZE
);
657 port
->port
.dev
= &dev
->dev
;
658 port
->port
.mapbase
= dev
->res
.start
;
659 port
->port
.membase
= base
;
660 port
->port
.iotype
= UPIO_MEM
;
661 port
->port
.irq
= dev
->irq
[0];
662 port
->port
.uartclk
= 14745600;
663 port
->port
.fifosize
= 16;
664 port
->port
.ops
= &amba_pl010_pops
;
665 port
->port
.flags
= UPF_BOOT_AUTOCONF
;
668 port
->data
= dev
->dev
.platform_data
;
670 amba_ports
[i
] = port
;
672 amba_set_drvdata(dev
, port
);
673 ret
= uart_add_one_port(&amba_reg
, &port
->port
);
675 amba_set_drvdata(dev
, NULL
);
676 amba_ports
[i
] = NULL
;
686 static int pl010_remove(struct amba_device
*dev
)
688 struct uart_amba_port
*port
= amba_get_drvdata(dev
);
691 amba_set_drvdata(dev
, NULL
);
693 uart_remove_one_port(&amba_reg
, &port
->port
);
695 for (i
= 0; i
< ARRAY_SIZE(amba_ports
); i
++)
696 if (amba_ports
[i
] == port
)
697 amba_ports
[i
] = NULL
;
699 iounmap(port
->port
.membase
);
705 static int pl010_suspend(struct amba_device
*dev
, pm_message_t state
)
707 struct uart_amba_port
*uap
= amba_get_drvdata(dev
);
710 uart_suspend_port(&amba_reg
, &uap
->port
);
715 static int pl010_resume(struct amba_device
*dev
)
717 struct uart_amba_port
*uap
= amba_get_drvdata(dev
);
720 uart_resume_port(&amba_reg
, &uap
->port
);
725 static struct amba_id pl010_ids
[] __initdata
= {
733 static struct amba_driver pl010_driver
= {
735 .name
= "uart-pl010",
737 .id_table
= pl010_ids
,
738 .probe
= pl010_probe
,
739 .remove
= pl010_remove
,
740 .suspend
= pl010_suspend
,
741 .resume
= pl010_resume
,
744 static int __init
pl010_init(void)
748 printk(KERN_INFO
"Serial: AMBA driver $Revision: 1.41 $\n");
750 ret
= uart_register_driver(&amba_reg
);
752 ret
= amba_driver_register(&pl010_driver
);
754 uart_unregister_driver(&amba_reg
);
759 static void __exit
pl010_exit(void)
761 amba_driver_unregister(&pl010_driver
);
762 uart_unregister_driver(&amba_reg
);
765 module_init(pl010_init
);
766 module_exit(pl010_exit
);
768 MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
769 MODULE_DESCRIPTION("ARM AMBA serial port driver $Revision: 1.41 $");
770 MODULE_LICENSE("GPL");