1 // SPDX-License-Identifier: GPL-2.0+
3 * Driver for AMBA serial ports
5 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
7 * Copyright 1999 ARM Limited
8 * Copyright (C) 2000 Deep Blue Solutions Ltd.
10 * This is a generic driver for ARM AMBA-type serial ports. They
11 * have a lot of 16550-like features, but are not register compatible.
12 * Note that although they do have CTS, DCD and DSR inputs, they do
13 * not have an RI input, nor do they have DTR or RTS outputs. If
14 * required, these have to be supplied via some other means (eg, GPIO)
15 * and hooked into this driver.
18 #include <linux/module.h>
19 #include <linux/ioport.h>
20 #include <linux/init.h>
21 #include <linux/console.h>
22 #include <linux/sysrq.h>
23 #include <linux/device.h>
24 #include <linux/tty.h>
25 #include <linux/tty_flip.h>
26 #include <linux/serial_core.h>
27 #include <linux/serial.h>
28 #include <linux/amba/bus.h>
29 #include <linux/amba/serial.h>
30 #include <linux/clk.h>
31 #include <linux/slab.h>
36 #define SERIAL_AMBA_MAJOR 204
37 #define SERIAL_AMBA_MINOR 16
38 #define SERIAL_AMBA_NR UART_NR
40 #define AMBA_ISR_PASS_LIMIT 256
42 #define UART_RX_DATA(s) (((s) & UART01x_FR_RXFE) == 0)
43 #define UART_TX_READY(s) (((s) & UART01x_FR_TXFF) == 0)
45 #define UART_DUMMY_RSR_RX 256
46 #define UART_PORT_SIZE 64
49 * We wrap our port structure around the generic uart_port.
51 struct uart_amba_port
{
52 struct uart_port port
;
54 struct amba_device
*dev
;
55 struct amba_pl010_data
*data
;
56 unsigned int old_status
;
59 static void pl010_stop_tx(struct uart_port
*port
)
61 struct uart_amba_port
*uap
=
62 container_of(port
, struct uart_amba_port
, port
);
65 cr
= readb(uap
->port
.membase
+ UART010_CR
);
66 cr
&= ~UART010_CR_TIE
;
67 writel(cr
, uap
->port
.membase
+ UART010_CR
);
70 static void pl010_start_tx(struct uart_port
*port
)
72 struct uart_amba_port
*uap
=
73 container_of(port
, struct uart_amba_port
, port
);
76 cr
= readb(uap
->port
.membase
+ UART010_CR
);
78 writel(cr
, uap
->port
.membase
+ UART010_CR
);
81 static void pl010_stop_rx(struct uart_port
*port
)
83 struct uart_amba_port
*uap
=
84 container_of(port
, struct uart_amba_port
, port
);
87 cr
= readb(uap
->port
.membase
+ UART010_CR
);
88 cr
&= ~(UART010_CR_RIE
| UART010_CR_RTIE
);
89 writel(cr
, uap
->port
.membase
+ UART010_CR
);
92 static void pl010_disable_ms(struct uart_port
*port
)
94 struct uart_amba_port
*uap
= (struct uart_amba_port
*)port
;
97 cr
= readb(uap
->port
.membase
+ UART010_CR
);
98 cr
&= ~UART010_CR_MSIE
;
99 writel(cr
, uap
->port
.membase
+ UART010_CR
);
102 static void pl010_enable_ms(struct uart_port
*port
)
104 struct uart_amba_port
*uap
=
105 container_of(port
, struct uart_amba_port
, port
);
108 cr
= readb(uap
->port
.membase
+ UART010_CR
);
109 cr
|= UART010_CR_MSIE
;
110 writel(cr
, uap
->port
.membase
+ UART010_CR
);
113 static void pl010_rx_chars(struct uart_port
*port
)
115 unsigned int status
, rsr
, max_count
= 256;
118 status
= readb(port
->membase
+ UART01x_FR
);
119 while (UART_RX_DATA(status
) && max_count
--) {
120 ch
= readb(port
->membase
+ UART01x_DR
);
126 * Note that the error handling code is
127 * out of the main execution path
129 rsr
= readb(port
->membase
+ UART01x_RSR
) | UART_DUMMY_RSR_RX
;
130 if (unlikely(rsr
& UART01x_RSR_ANY
)) {
131 writel(0, port
->membase
+ UART01x_ECR
);
133 if (rsr
& UART01x_RSR_BE
) {
134 rsr
&= ~(UART01x_RSR_FE
| UART01x_RSR_PE
);
136 if (uart_handle_break(port
))
138 } else if (rsr
& UART01x_RSR_PE
)
139 port
->icount
.parity
++;
140 else if (rsr
& UART01x_RSR_FE
)
141 port
->icount
.frame
++;
142 if (rsr
& UART01x_RSR_OE
)
143 port
->icount
.overrun
++;
145 rsr
&= port
->read_status_mask
;
147 if (rsr
& UART01x_RSR_BE
)
149 else if (rsr
& UART01x_RSR_PE
)
151 else if (rsr
& UART01x_RSR_FE
)
155 if (uart_handle_sysrq_char(port
, ch
))
158 uart_insert_char(port
, rsr
, UART01x_RSR_OE
, ch
, flag
);
161 status
= readb(port
->membase
+ UART01x_FR
);
163 tty_flip_buffer_push(&port
->state
->port
);
166 static void pl010_tx_chars(struct uart_port
*port
)
170 uart_port_tx_limited(port
, ch
, port
->fifosize
>> 1,
172 writel(ch
, port
->membase
+ UART01x_DR
),
176 static void pl010_modem_status(struct uart_amba_port
*uap
)
178 struct uart_port
*port
= &uap
->port
;
179 unsigned int status
, delta
;
181 writel(0, port
->membase
+ UART010_ICR
);
183 status
= readb(port
->membase
+ UART01x_FR
) & UART01x_FR_MODEM_ANY
;
185 delta
= status
^ uap
->old_status
;
186 uap
->old_status
= status
;
191 if (delta
& UART01x_FR_DCD
)
192 uart_handle_dcd_change(port
, status
& UART01x_FR_DCD
);
194 if (delta
& UART01x_FR_DSR
)
197 if (delta
& UART01x_FR_CTS
)
198 uart_handle_cts_change(port
, status
& UART01x_FR_CTS
);
200 wake_up_interruptible(&port
->state
->port
.delta_msr_wait
);
203 static irqreturn_t
pl010_int(int irq
, void *dev_id
)
205 struct uart_amba_port
*uap
= dev_id
;
206 struct uart_port
*port
= &uap
->port
;
207 unsigned int status
, pass_counter
= AMBA_ISR_PASS_LIMIT
;
210 uart_port_lock(port
);
212 status
= readb(port
->membase
+ UART010_IIR
);
215 if (status
& (UART010_IIR_RTIS
| UART010_IIR_RIS
))
216 pl010_rx_chars(port
);
217 if (status
& UART010_IIR_MIS
)
218 pl010_modem_status(uap
);
219 if (status
& UART010_IIR_TIS
)
220 pl010_tx_chars(port
);
222 if (pass_counter
-- == 0)
225 status
= readb(port
->membase
+ UART010_IIR
);
226 } while (status
& (UART010_IIR_RTIS
| UART010_IIR_RIS
|
231 uart_port_unlock(port
);
233 return IRQ_RETVAL(handled
);
236 static unsigned int pl010_tx_empty(struct uart_port
*port
)
238 unsigned int status
= readb(port
->membase
+ UART01x_FR
);
240 return status
& UART01x_FR_BUSY
? 0 : TIOCSER_TEMT
;
243 static unsigned int pl010_get_mctrl(struct uart_port
*port
)
245 unsigned int result
= 0;
248 status
= readb(port
->membase
+ UART01x_FR
);
249 if (status
& UART01x_FR_DCD
)
251 if (status
& UART01x_FR_DSR
)
253 if (status
& UART01x_FR_CTS
)
259 static void pl010_set_mctrl(struct uart_port
*port
, unsigned int mctrl
)
261 struct uart_amba_port
*uap
=
262 container_of(port
, struct uart_amba_port
, port
);
265 uap
->data
->set_mctrl(uap
->dev
, port
->membase
, mctrl
);
268 static void pl010_break_ctl(struct uart_port
*port
, int break_state
)
273 uart_port_lock_irqsave(port
, &flags
);
274 lcr_h
= readb(port
->membase
+ UART010_LCRH
);
275 if (break_state
== -1)
276 lcr_h
|= UART01x_LCRH_BRK
;
278 lcr_h
&= ~UART01x_LCRH_BRK
;
279 writel(lcr_h
, port
->membase
+ UART010_LCRH
);
280 uart_port_unlock_irqrestore(port
, flags
);
283 static int pl010_startup(struct uart_port
*port
)
285 struct uart_amba_port
*uap
=
286 container_of(port
, struct uart_amba_port
, port
);
290 * Try to enable the clock producer.
292 retval
= clk_prepare_enable(uap
->clk
);
296 port
->uartclk
= clk_get_rate(uap
->clk
);
301 retval
= request_irq(port
->irq
, pl010_int
, 0, "uart-pl010", uap
);
306 * initialise the old status of the modem signals
308 uap
->old_status
= readb(port
->membase
+ UART01x_FR
) & UART01x_FR_MODEM_ANY
;
311 * Finally, enable interrupts
313 writel(UART01x_CR_UARTEN
| UART010_CR_RIE
| UART010_CR_RTIE
,
314 port
->membase
+ UART010_CR
);
319 clk_disable_unprepare(uap
->clk
);
324 static void pl010_shutdown(struct uart_port
*port
)
326 struct uart_amba_port
*uap
=
327 container_of(port
, struct uart_amba_port
, port
);
332 free_irq(port
->irq
, uap
);
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
);
345 * Shut down the clock producer
347 clk_disable_unprepare(uap
->clk
);
351 pl010_set_termios(struct uart_port
*port
, struct ktermios
*termios
,
352 const struct ktermios
*old
)
354 unsigned int lcr_h
, old_cr
;
356 unsigned int baud
, quot
;
359 * Ask the core to calculate the divisor for us.
361 baud
= uart_get_baud_rate(port
, termios
, old
, 0, port
->uartclk
/ 16);
362 quot
= uart_get_divisor(port
, baud
);
364 switch (termios
->c_cflag
& CSIZE
) {
366 lcr_h
= UART01x_LCRH_WLEN_5
;
369 lcr_h
= UART01x_LCRH_WLEN_6
;
372 lcr_h
= UART01x_LCRH_WLEN_7
;
375 lcr_h
= UART01x_LCRH_WLEN_8
;
378 if (termios
->c_cflag
& CSTOPB
)
379 lcr_h
|= UART01x_LCRH_STP2
;
380 if (termios
->c_cflag
& PARENB
) {
381 lcr_h
|= UART01x_LCRH_PEN
;
382 if (!(termios
->c_cflag
& PARODD
))
383 lcr_h
|= UART01x_LCRH_EPS
;
385 if (port
->fifosize
> 1)
386 lcr_h
|= UART01x_LCRH_FEN
;
388 uart_port_lock_irqsave(port
, &flags
);
391 * Update the per-port timeout.
393 uart_update_timeout(port
, termios
->c_cflag
, baud
);
395 port
->read_status_mask
= UART01x_RSR_OE
;
396 if (termios
->c_iflag
& INPCK
)
397 port
->read_status_mask
|= UART01x_RSR_FE
| UART01x_RSR_PE
;
398 if (termios
->c_iflag
& (IGNBRK
| BRKINT
| PARMRK
))
399 port
->read_status_mask
|= UART01x_RSR_BE
;
402 * Characters to ignore
404 port
->ignore_status_mask
= 0;
405 if (termios
->c_iflag
& IGNPAR
)
406 port
->ignore_status_mask
|= UART01x_RSR_FE
| UART01x_RSR_PE
;
407 if (termios
->c_iflag
& IGNBRK
) {
408 port
->ignore_status_mask
|= UART01x_RSR_BE
;
410 * If we're ignoring parity and break indicators,
411 * ignore overruns too (for real raw support).
413 if (termios
->c_iflag
& IGNPAR
)
414 port
->ignore_status_mask
|= UART01x_RSR_OE
;
418 * Ignore all characters if CREAD is not set.
420 if ((termios
->c_cflag
& CREAD
) == 0)
421 port
->ignore_status_mask
|= UART_DUMMY_RSR_RX
;
423 old_cr
= readb(port
->membase
+ UART010_CR
) & ~UART010_CR_MSIE
;
425 if (UART_ENABLE_MS(port
, termios
->c_cflag
))
426 old_cr
|= UART010_CR_MSIE
;
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 uart_port_unlock_irqrestore(port
, flags
);
444 static void pl010_set_ldisc(struct uart_port
*port
, struct ktermios
*termios
)
446 if (termios
->c_line
== N_PPS
) {
447 port
->flags
|= UPF_HARDPPS_CD
;
448 uart_port_lock_irq(port
);
449 pl010_enable_ms(port
);
450 uart_port_unlock_irq(port
);
452 port
->flags
&= ~UPF_HARDPPS_CD
;
453 if (!UART_ENABLE_MS(port
, termios
->c_cflag
)) {
454 uart_port_lock_irq(port
);
455 pl010_disable_ms(port
);
456 uart_port_unlock_irq(port
);
461 static const char *pl010_type(struct uart_port
*port
)
463 return port
->type
== PORT_AMBA
? "AMBA" : NULL
;
467 * Release the memory region(s) being used by 'port'
469 static void pl010_release_port(struct uart_port
*port
)
471 release_mem_region(port
->mapbase
, UART_PORT_SIZE
);
475 * Request the memory region(s) being used by 'port'
477 static int pl010_request_port(struct uart_port
*port
)
479 return request_mem_region(port
->mapbase
, UART_PORT_SIZE
, "uart-pl010")
480 != NULL
? 0 : -EBUSY
;
484 * Configure/autoconfigure the port.
486 static void pl010_config_port(struct uart_port
*port
, int flags
)
488 if (flags
& UART_CONFIG_TYPE
) {
489 port
->type
= PORT_AMBA
;
490 pl010_request_port(port
);
495 * verify the new serial_struct (for TIOCSSERIAL).
497 static int pl010_verify_port(struct uart_port
*port
, struct serial_struct
*ser
)
500 if (ser
->type
!= PORT_UNKNOWN
&& ser
->type
!= PORT_AMBA
)
502 if (ser
->irq
< 0 || ser
->irq
>= irq_get_nr_irqs())
504 if (ser
->baud_base
< 9600)
509 static const struct uart_ops amba_pl010_pops
= {
510 .tx_empty
= pl010_tx_empty
,
511 .set_mctrl
= pl010_set_mctrl
,
512 .get_mctrl
= pl010_get_mctrl
,
513 .stop_tx
= pl010_stop_tx
,
514 .start_tx
= pl010_start_tx
,
515 .stop_rx
= pl010_stop_rx
,
516 .enable_ms
= pl010_enable_ms
,
517 .break_ctl
= pl010_break_ctl
,
518 .startup
= pl010_startup
,
519 .shutdown
= pl010_shutdown
,
520 .set_termios
= pl010_set_termios
,
521 .set_ldisc
= pl010_set_ldisc
,
523 .release_port
= pl010_release_port
,
524 .request_port
= pl010_request_port
,
525 .config_port
= pl010_config_port
,
526 .verify_port
= pl010_verify_port
,
529 static struct uart_amba_port
*amba_ports
[UART_NR
];
531 #ifdef CONFIG_SERIAL_AMBA_PL010_CONSOLE
533 static void pl010_console_putchar(struct uart_port
*port
, unsigned char ch
)
538 status
= readb(port
->membase
+ UART01x_FR
);
540 } while (!UART_TX_READY(status
));
541 writel(ch
, port
->membase
+ UART01x_DR
);
545 pl010_console_write(struct console
*co
, const char *s
, unsigned int count
)
547 struct uart_amba_port
*uap
= amba_ports
[co
->index
];
548 struct uart_port
*port
= &uap
->port
;
549 unsigned int status
, old_cr
;
551 clk_enable(uap
->clk
);
554 * First save the CR then disable the interrupts
556 old_cr
= readb(port
->membase
+ UART010_CR
);
557 writel(UART01x_CR_UARTEN
, port
->membase
+ UART010_CR
);
559 uart_console_write(port
, s
, count
, pl010_console_putchar
);
562 * Finally, wait for transmitter to become empty
563 * and restore the TCR
566 status
= readb(port
->membase
+ UART01x_FR
);
568 } while (status
& UART01x_FR_BUSY
);
569 writel(old_cr
, port
->membase
+ UART010_CR
);
571 clk_disable(uap
->clk
);
575 pl010_console_get_options(struct uart_amba_port
*uap
, int *baud
,
576 int *parity
, int *bits
)
578 if (readb(uap
->port
.membase
+ UART010_CR
) & UART01x_CR_UARTEN
) {
579 unsigned int lcr_h
, quot
;
580 lcr_h
= readb(uap
->port
.membase
+ UART010_LCRH
);
583 if (lcr_h
& UART01x_LCRH_PEN
) {
584 if (lcr_h
& UART01x_LCRH_EPS
)
590 if ((lcr_h
& 0x60) == UART01x_LCRH_WLEN_7
)
595 quot
= readb(uap
->port
.membase
+ UART010_LCRL
) |
596 readb(uap
->port
.membase
+ UART010_LCRM
) << 8;
597 *baud
= uap
->port
.uartclk
/ (16 * (quot
+ 1));
601 static int __init
pl010_console_setup(struct console
*co
, char *options
)
603 struct uart_amba_port
*uap
;
611 * Check whether an invalid uart number has been specified, and
612 * if so, search for the first available port that does have
615 if (co
->index
>= UART_NR
)
617 uap
= amba_ports
[co
->index
];
621 ret
= clk_prepare(uap
->clk
);
625 uap
->port
.uartclk
= clk_get_rate(uap
->clk
);
628 uart_parse_options(options
, &baud
, &parity
, &bits
, &flow
);
630 pl010_console_get_options(uap
, &baud
, &parity
, &bits
);
632 return uart_set_options(&uap
->port
, co
, baud
, parity
, bits
, flow
);
635 static struct uart_driver amba_reg
;
636 static struct console amba_console
= {
638 .write
= pl010_console_write
,
639 .device
= uart_console_device
,
640 .setup
= pl010_console_setup
,
641 .flags
= CON_PRINTBUFFER
,
646 #define AMBA_CONSOLE &amba_console
648 #define AMBA_CONSOLE NULL
651 static DEFINE_MUTEX(amba_reg_lock
);
652 static struct uart_driver amba_reg
= {
653 .owner
= THIS_MODULE
,
654 .driver_name
= "ttyAM",
656 .major
= SERIAL_AMBA_MAJOR
,
657 .minor
= SERIAL_AMBA_MINOR
,
659 .cons
= AMBA_CONSOLE
,
662 static int pl010_probe(struct amba_device
*dev
, const struct amba_id
*id
)
664 struct uart_amba_port
*uap
;
668 for (i
= 0; i
< ARRAY_SIZE(amba_ports
); i
++)
669 if (amba_ports
[i
] == NULL
)
672 if (i
== ARRAY_SIZE(amba_ports
))
675 uap
= devm_kzalloc(&dev
->dev
, sizeof(struct uart_amba_port
),
680 base
= devm_ioremap(&dev
->dev
, dev
->res
.start
,
681 resource_size(&dev
->res
));
685 uap
->clk
= devm_clk_get(&dev
->dev
, NULL
);
686 if (IS_ERR(uap
->clk
))
687 return PTR_ERR(uap
->clk
);
689 uap
->port
.dev
= &dev
->dev
;
690 uap
->port
.mapbase
= dev
->res
.start
;
691 uap
->port
.membase
= base
;
692 uap
->port
.iotype
= UPIO_MEM
;
693 uap
->port
.irq
= dev
->irq
[0];
694 uap
->port
.fifosize
= 16;
695 uap
->port
.has_sysrq
= IS_ENABLED(CONFIG_SERIAL_AMBA_PL010_CONSOLE
);
696 uap
->port
.ops
= &amba_pl010_pops
;
697 uap
->port
.flags
= UPF_BOOT_AUTOCONF
;
700 uap
->data
= dev_get_platdata(&dev
->dev
);
704 amba_set_drvdata(dev
, uap
);
706 mutex_lock(&amba_reg_lock
);
707 if (!amba_reg
.state
) {
708 ret
= uart_register_driver(&amba_reg
);
710 mutex_unlock(&amba_reg_lock
);
711 dev_err(uap
->port
.dev
,
712 "Failed to register AMBA-PL010 driver\n");
716 mutex_unlock(&amba_reg_lock
);
718 ret
= uart_add_one_port(&amba_reg
, &uap
->port
);
720 amba_ports
[i
] = NULL
;
725 static void pl010_remove(struct amba_device
*dev
)
727 struct uart_amba_port
*uap
= amba_get_drvdata(dev
);
731 uart_remove_one_port(&amba_reg
, &uap
->port
);
733 for (i
= 0; i
< ARRAY_SIZE(amba_ports
); i
++)
734 if (amba_ports
[i
] == uap
)
735 amba_ports
[i
] = NULL
;
736 else if (amba_ports
[i
])
740 uart_unregister_driver(&amba_reg
);
743 #ifdef CONFIG_PM_SLEEP
744 static int pl010_suspend(struct device
*dev
)
746 struct uart_amba_port
*uap
= dev_get_drvdata(dev
);
749 uart_suspend_port(&amba_reg
, &uap
->port
);
754 static int pl010_resume(struct device
*dev
)
756 struct uart_amba_port
*uap
= dev_get_drvdata(dev
);
759 uart_resume_port(&amba_reg
, &uap
->port
);
765 static SIMPLE_DEV_PM_OPS(pl010_dev_pm_ops
, pl010_suspend
, pl010_resume
);
767 static const struct amba_id pl010_ids
[] = {
775 MODULE_DEVICE_TABLE(amba
, pl010_ids
);
777 static struct amba_driver pl010_driver
= {
779 .name
= "uart-pl010",
780 .pm
= &pl010_dev_pm_ops
,
782 .id_table
= pl010_ids
,
783 .probe
= pl010_probe
,
784 .remove
= pl010_remove
,
787 static int __init
pl010_init(void)
789 printk(KERN_INFO
"Serial: AMBA driver\n");
791 return amba_driver_register(&pl010_driver
);
794 static void __exit
pl010_exit(void)
796 amba_driver_unregister(&pl010_driver
);
799 module_init(pl010_init
);
800 module_exit(pl010_exit
);
802 MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
803 MODULE_DESCRIPTION("ARM AMBA serial port driver");
804 MODULE_LICENSE("GPL");