2 * Atheros AR933X SoC built-in UART driver
4 * Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
6 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 as published
10 * by the Free Software Foundation.
13 #include <linux/module.h>
14 #include <linux/ioport.h>
15 #include <linux/init.h>
16 #include <linux/console.h>
17 #include <linux/sysrq.h>
18 #include <linux/delay.h>
19 #include <linux/platform_device.h>
20 #include <linux/tty.h>
21 #include <linux/tty_flip.h>
22 #include <linux/serial_core.h>
23 #include <linux/serial.h>
24 #include <linux/slab.h>
26 #include <linux/irq.h>
27 #include <linux/clk.h>
29 #include <asm/div64.h>
31 #include <asm/mach-ath79/ar933x_uart.h>
33 #define DRIVER_NAME "ar933x-uart"
35 #define AR933X_UART_MAX_SCALE 0xff
36 #define AR933X_UART_MAX_STEP 0xffff
38 #define AR933X_UART_MIN_BAUD 300
39 #define AR933X_UART_MAX_BAUD 3000000
41 #define AR933X_DUMMY_STATUS_RD 0x01
43 static struct uart_driver ar933x_uart_driver
;
45 struct ar933x_uart_port
{
46 struct uart_port port
;
47 unsigned int ier
; /* shadow Interrupt Enable Register */
48 unsigned int min_baud
;
49 unsigned int max_baud
;
53 static inline unsigned int ar933x_uart_read(struct ar933x_uart_port
*up
,
56 return readl(up
->port
.membase
+ offset
);
59 static inline void ar933x_uart_write(struct ar933x_uart_port
*up
,
60 int offset
, unsigned int value
)
62 writel(value
, up
->port
.membase
+ offset
);
65 static inline void ar933x_uart_rmw(struct ar933x_uart_port
*up
,
72 t
= ar933x_uart_read(up
, offset
);
75 ar933x_uart_write(up
, offset
, t
);
78 static inline void ar933x_uart_rmw_set(struct ar933x_uart_port
*up
,
82 ar933x_uart_rmw(up
, offset
, 0, val
);
85 static inline void ar933x_uart_rmw_clear(struct ar933x_uart_port
*up
,
89 ar933x_uart_rmw(up
, offset
, val
, 0);
92 static inline void ar933x_uart_start_tx_interrupt(struct ar933x_uart_port
*up
)
94 up
->ier
|= AR933X_UART_INT_TX_EMPTY
;
95 ar933x_uart_write(up
, AR933X_UART_INT_EN_REG
, up
->ier
);
98 static inline void ar933x_uart_stop_tx_interrupt(struct ar933x_uart_port
*up
)
100 up
->ier
&= ~AR933X_UART_INT_TX_EMPTY
;
101 ar933x_uart_write(up
, AR933X_UART_INT_EN_REG
, up
->ier
);
104 static inline void ar933x_uart_putc(struct ar933x_uart_port
*up
, int ch
)
108 rdata
= ch
& AR933X_UART_DATA_TX_RX_MASK
;
109 rdata
|= AR933X_UART_DATA_TX_CSR
;
110 ar933x_uart_write(up
, AR933X_UART_DATA_REG
, rdata
);
113 static unsigned int ar933x_uart_tx_empty(struct uart_port
*port
)
115 struct ar933x_uart_port
*up
= (struct ar933x_uart_port
*) port
;
119 spin_lock_irqsave(&up
->port
.lock
, flags
);
120 rdata
= ar933x_uart_read(up
, AR933X_UART_DATA_REG
);
121 spin_unlock_irqrestore(&up
->port
.lock
, flags
);
123 return (rdata
& AR933X_UART_DATA_TX_CSR
) ? 0 : TIOCSER_TEMT
;
126 static unsigned int ar933x_uart_get_mctrl(struct uart_port
*port
)
131 static void ar933x_uart_set_mctrl(struct uart_port
*port
, unsigned int mctrl
)
135 static void ar933x_uart_start_tx(struct uart_port
*port
)
137 struct ar933x_uart_port
*up
= (struct ar933x_uart_port
*) port
;
139 ar933x_uart_start_tx_interrupt(up
);
142 static void ar933x_uart_stop_tx(struct uart_port
*port
)
144 struct ar933x_uart_port
*up
= (struct ar933x_uart_port
*) port
;
146 ar933x_uart_stop_tx_interrupt(up
);
149 static void ar933x_uart_stop_rx(struct uart_port
*port
)
151 struct ar933x_uart_port
*up
= (struct ar933x_uart_port
*) port
;
153 up
->ier
&= ~AR933X_UART_INT_RX_VALID
;
154 ar933x_uart_write(up
, AR933X_UART_INT_EN_REG
, up
->ier
);
157 static void ar933x_uart_break_ctl(struct uart_port
*port
, int break_state
)
159 struct ar933x_uart_port
*up
= (struct ar933x_uart_port
*) port
;
162 spin_lock_irqsave(&up
->port
.lock
, flags
);
163 if (break_state
== -1)
164 ar933x_uart_rmw_set(up
, AR933X_UART_CS_REG
,
165 AR933X_UART_CS_TX_BREAK
);
167 ar933x_uart_rmw_clear(up
, AR933X_UART_CS_REG
,
168 AR933X_UART_CS_TX_BREAK
);
169 spin_unlock_irqrestore(&up
->port
.lock
, flags
);
172 static void ar933x_uart_enable_ms(struct uart_port
*port
)
177 * baudrate = (clk / (scale + 1)) * (step * (1 / 2^17))
179 static unsigned long ar933x_uart_get_baud(unsigned int clk
,
186 div
= (2 << 16) * (scale
+ 1);
195 static void ar933x_uart_get_scale_step(unsigned int clk
,
207 for (tscale
= 0; tscale
< AR933X_UART_MAX_SCALE
; tscale
++) {
211 tstep
= baud
* (tscale
+ 1);
215 if (tstep
> AR933X_UART_MAX_STEP
)
218 diff
= abs(ar933x_uart_get_baud(clk
, tscale
, tstep
) - baud
);
219 if (diff
< min_diff
) {
227 static void ar933x_uart_set_termios(struct uart_port
*port
,
228 struct ktermios
*new,
229 struct ktermios
*old
)
231 struct ar933x_uart_port
*up
= (struct ar933x_uart_port
*) port
;
234 unsigned int baud
, scale
, step
;
236 /* Only CS8 is supported */
237 new->c_cflag
&= ~CSIZE
;
240 /* Only one stop bit is supported */
241 new->c_cflag
&= ~CSTOPB
;
244 if (new->c_cflag
& PARENB
) {
245 if (!(new->c_cflag
& PARODD
))
246 cs
|= AR933X_UART_CS_PARITY_EVEN
;
248 cs
|= AR933X_UART_CS_PARITY_ODD
;
250 cs
|= AR933X_UART_CS_PARITY_NONE
;
253 /* Mark/space parity is not supported */
254 new->c_cflag
&= ~CMSPAR
;
256 baud
= uart_get_baud_rate(port
, new, old
, up
->min_baud
, up
->max_baud
);
257 ar933x_uart_get_scale_step(port
->uartclk
, baud
, &scale
, &step
);
260 * Ok, we're now changing the port state. Do it with
261 * interrupts disabled.
263 spin_lock_irqsave(&up
->port
.lock
, flags
);
265 /* disable the UART */
266 ar933x_uart_rmw_clear(up
, AR933X_UART_CS_REG
,
267 AR933X_UART_CS_IF_MODE_M
<< AR933X_UART_CS_IF_MODE_S
);
269 /* Update the per-port timeout. */
270 uart_update_timeout(port
, new->c_cflag
, baud
);
272 up
->port
.ignore_status_mask
= 0;
274 /* ignore all characters if CREAD is not set */
275 if ((new->c_cflag
& CREAD
) == 0)
276 up
->port
.ignore_status_mask
|= AR933X_DUMMY_STATUS_RD
;
278 ar933x_uart_write(up
, AR933X_UART_CLOCK_REG
,
279 scale
<< AR933X_UART_CLOCK_SCALE_S
| step
);
281 /* setup configuration register */
282 ar933x_uart_rmw(up
, AR933X_UART_CS_REG
, AR933X_UART_CS_PARITY_M
, cs
);
284 /* enable host interrupt */
285 ar933x_uart_rmw_set(up
, AR933X_UART_CS_REG
,
286 AR933X_UART_CS_HOST_INT_EN
);
288 /* reenable the UART */
289 ar933x_uart_rmw(up
, AR933X_UART_CS_REG
,
290 AR933X_UART_CS_IF_MODE_M
<< AR933X_UART_CS_IF_MODE_S
,
291 AR933X_UART_CS_IF_MODE_DCE
<< AR933X_UART_CS_IF_MODE_S
);
293 spin_unlock_irqrestore(&up
->port
.lock
, flags
);
295 if (tty_termios_baud_rate(new))
296 tty_termios_encode_baud_rate(new, baud
, baud
);
299 static void ar933x_uart_rx_chars(struct ar933x_uart_port
*up
)
301 struct tty_port
*port
= &up
->port
.state
->port
;
308 rdata
= ar933x_uart_read(up
, AR933X_UART_DATA_REG
);
309 if ((rdata
& AR933X_UART_DATA_RX_CSR
) == 0)
312 /* remove the character from the FIFO */
313 ar933x_uart_write(up
, AR933X_UART_DATA_REG
,
314 AR933X_UART_DATA_RX_CSR
);
316 up
->port
.icount
.rx
++;
317 ch
= rdata
& AR933X_UART_DATA_TX_RX_MASK
;
319 if (uart_handle_sysrq_char(&up
->port
, ch
))
322 if ((up
->port
.ignore_status_mask
& AR933X_DUMMY_STATUS_RD
) == 0)
323 tty_insert_flip_char(port
, ch
, TTY_NORMAL
);
324 } while (max_count
-- > 0);
326 spin_unlock(&up
->port
.lock
);
327 tty_flip_buffer_push(port
);
328 spin_lock(&up
->port
.lock
);
331 static void ar933x_uart_tx_chars(struct ar933x_uart_port
*up
)
333 struct circ_buf
*xmit
= &up
->port
.state
->xmit
;
336 if (uart_tx_stopped(&up
->port
))
339 count
= up
->port
.fifosize
;
343 rdata
= ar933x_uart_read(up
, AR933X_UART_DATA_REG
);
344 if ((rdata
& AR933X_UART_DATA_TX_CSR
) == 0)
347 if (up
->port
.x_char
) {
348 ar933x_uart_putc(up
, up
->port
.x_char
);
349 up
->port
.icount
.tx
++;
354 if (uart_circ_empty(xmit
))
357 ar933x_uart_putc(up
, xmit
->buf
[xmit
->tail
]);
359 xmit
->tail
= (xmit
->tail
+ 1) & (UART_XMIT_SIZE
- 1);
360 up
->port
.icount
.tx
++;
361 } while (--count
> 0);
363 if (uart_circ_chars_pending(xmit
) < WAKEUP_CHARS
)
364 uart_write_wakeup(&up
->port
);
366 if (!uart_circ_empty(xmit
))
367 ar933x_uart_start_tx_interrupt(up
);
370 static irqreturn_t
ar933x_uart_interrupt(int irq
, void *dev_id
)
372 struct ar933x_uart_port
*up
= dev_id
;
375 status
= ar933x_uart_read(up
, AR933X_UART_CS_REG
);
376 if ((status
& AR933X_UART_CS_HOST_INT
) == 0)
379 spin_lock(&up
->port
.lock
);
381 status
= ar933x_uart_read(up
, AR933X_UART_INT_REG
);
382 status
&= ar933x_uart_read(up
, AR933X_UART_INT_EN_REG
);
384 if (status
& AR933X_UART_INT_RX_VALID
) {
385 ar933x_uart_write(up
, AR933X_UART_INT_REG
,
386 AR933X_UART_INT_RX_VALID
);
387 ar933x_uart_rx_chars(up
);
390 if (status
& AR933X_UART_INT_TX_EMPTY
) {
391 ar933x_uart_write(up
, AR933X_UART_INT_REG
,
392 AR933X_UART_INT_TX_EMPTY
);
393 ar933x_uart_stop_tx_interrupt(up
);
394 ar933x_uart_tx_chars(up
);
397 spin_unlock(&up
->port
.lock
);
402 static int ar933x_uart_startup(struct uart_port
*port
)
404 struct ar933x_uart_port
*up
= (struct ar933x_uart_port
*) port
;
408 ret
= request_irq(up
->port
.irq
, ar933x_uart_interrupt
,
409 up
->port
.irqflags
, dev_name(up
->port
.dev
), up
);
413 spin_lock_irqsave(&up
->port
.lock
, flags
);
415 /* Enable HOST interrupts */
416 ar933x_uart_rmw_set(up
, AR933X_UART_CS_REG
,
417 AR933X_UART_CS_HOST_INT_EN
);
419 /* Enable RX interrupts */
420 up
->ier
= AR933X_UART_INT_RX_VALID
;
421 ar933x_uart_write(up
, AR933X_UART_INT_EN_REG
, up
->ier
);
423 spin_unlock_irqrestore(&up
->port
.lock
, flags
);
428 static void ar933x_uart_shutdown(struct uart_port
*port
)
430 struct ar933x_uart_port
*up
= (struct ar933x_uart_port
*) port
;
432 /* Disable all interrupts */
434 ar933x_uart_write(up
, AR933X_UART_INT_EN_REG
, up
->ier
);
436 /* Disable break condition */
437 ar933x_uart_rmw_clear(up
, AR933X_UART_CS_REG
,
438 AR933X_UART_CS_TX_BREAK
);
440 free_irq(up
->port
.irq
, up
);
443 static const char *ar933x_uart_type(struct uart_port
*port
)
445 return (port
->type
== PORT_AR933X
) ? "AR933X UART" : NULL
;
448 static void ar933x_uart_release_port(struct uart_port
*port
)
450 /* Nothing to release ... */
453 static int ar933x_uart_request_port(struct uart_port
*port
)
455 /* UARTs always present */
459 static void ar933x_uart_config_port(struct uart_port
*port
, int flags
)
461 if (flags
& UART_CONFIG_TYPE
)
462 port
->type
= PORT_AR933X
;
465 static int ar933x_uart_verify_port(struct uart_port
*port
,
466 struct serial_struct
*ser
)
468 struct ar933x_uart_port
*up
= (struct ar933x_uart_port
*) port
;
470 if (ser
->type
!= PORT_UNKNOWN
&&
471 ser
->type
!= PORT_AR933X
)
474 if (ser
->irq
< 0 || ser
->irq
>= NR_IRQS
)
477 if (ser
->baud_base
< up
->min_baud
||
478 ser
->baud_base
> up
->max_baud
)
484 static struct uart_ops ar933x_uart_ops
= {
485 .tx_empty
= ar933x_uart_tx_empty
,
486 .set_mctrl
= ar933x_uart_set_mctrl
,
487 .get_mctrl
= ar933x_uart_get_mctrl
,
488 .stop_tx
= ar933x_uart_stop_tx
,
489 .start_tx
= ar933x_uart_start_tx
,
490 .stop_rx
= ar933x_uart_stop_rx
,
491 .enable_ms
= ar933x_uart_enable_ms
,
492 .break_ctl
= ar933x_uart_break_ctl
,
493 .startup
= ar933x_uart_startup
,
494 .shutdown
= ar933x_uart_shutdown
,
495 .set_termios
= ar933x_uart_set_termios
,
496 .type
= ar933x_uart_type
,
497 .release_port
= ar933x_uart_release_port
,
498 .request_port
= ar933x_uart_request_port
,
499 .config_port
= ar933x_uart_config_port
,
500 .verify_port
= ar933x_uart_verify_port
,
503 #ifdef CONFIG_SERIAL_AR933X_CONSOLE
505 static struct ar933x_uart_port
*
506 ar933x_console_ports
[CONFIG_SERIAL_AR933X_NR_UARTS
];
508 static void ar933x_uart_wait_xmitr(struct ar933x_uart_port
*up
)
511 unsigned int timeout
= 60000;
513 /* Wait up to 60ms for the character(s) to be sent. */
515 status
= ar933x_uart_read(up
, AR933X_UART_DATA_REG
);
519 } while ((status
& AR933X_UART_DATA_TX_CSR
) == 0);
522 static void ar933x_uart_console_putchar(struct uart_port
*port
, int ch
)
524 struct ar933x_uart_port
*up
= (struct ar933x_uart_port
*) port
;
526 ar933x_uart_wait_xmitr(up
);
527 ar933x_uart_putc(up
, ch
);
530 static void ar933x_uart_console_write(struct console
*co
, const char *s
,
533 struct ar933x_uart_port
*up
= ar933x_console_ports
[co
->index
];
538 local_irq_save(flags
);
542 else if (oops_in_progress
)
543 locked
= spin_trylock(&up
->port
.lock
);
545 spin_lock(&up
->port
.lock
);
548 * First save the IER then disable the interrupts
550 int_en
= ar933x_uart_read(up
, AR933X_UART_INT_EN_REG
);
551 ar933x_uart_write(up
, AR933X_UART_INT_EN_REG
, 0);
553 uart_console_write(&up
->port
, s
, count
, ar933x_uart_console_putchar
);
556 * Finally, wait for transmitter to become empty
557 * and restore the IER
559 ar933x_uart_wait_xmitr(up
);
560 ar933x_uart_write(up
, AR933X_UART_INT_EN_REG
, int_en
);
562 ar933x_uart_write(up
, AR933X_UART_INT_REG
, AR933X_UART_INT_ALLINTS
);
565 spin_unlock(&up
->port
.lock
);
567 local_irq_restore(flags
);
570 static int ar933x_uart_console_setup(struct console
*co
, char *options
)
572 struct ar933x_uart_port
*up
;
578 if (co
->index
< 0 || co
->index
>= CONFIG_SERIAL_AR933X_NR_UARTS
)
581 up
= ar933x_console_ports
[co
->index
];
586 uart_parse_options(options
, &baud
, &parity
, &bits
, &flow
);
588 return uart_set_options(&up
->port
, co
, baud
, parity
, bits
, flow
);
591 static struct console ar933x_uart_console
= {
593 .write
= ar933x_uart_console_write
,
594 .device
= uart_console_device
,
595 .setup
= ar933x_uart_console_setup
,
596 .flags
= CON_PRINTBUFFER
,
598 .data
= &ar933x_uart_driver
,
601 static void ar933x_uart_add_console_port(struct ar933x_uart_port
*up
)
603 ar933x_console_ports
[up
->port
.line
] = up
;
606 #define AR933X_SERIAL_CONSOLE (&ar933x_uart_console)
610 static inline void ar933x_uart_add_console_port(struct ar933x_uart_port
*up
) {}
612 #define AR933X_SERIAL_CONSOLE NULL
614 #endif /* CONFIG_SERIAL_AR933X_CONSOLE */
616 static struct uart_driver ar933x_uart_driver
= {
617 .owner
= THIS_MODULE
,
618 .driver_name
= DRIVER_NAME
,
619 .dev_name
= "ttyATH",
620 .nr
= CONFIG_SERIAL_AR933X_NR_UARTS
,
621 .cons
= AR933X_SERIAL_CONSOLE
,
624 static int ar933x_uart_probe(struct platform_device
*pdev
)
626 struct ar933x_uart_port
*up
;
627 struct uart_port
*port
;
628 struct resource
*mem_res
;
629 struct resource
*irq_res
;
638 if (id
> CONFIG_SERIAL_AR933X_NR_UARTS
)
641 irq_res
= platform_get_resource(pdev
, IORESOURCE_IRQ
, 0);
643 dev_err(&pdev
->dev
, "no IRQ resource\n");
647 up
= devm_kzalloc(&pdev
->dev
, sizeof(struct ar933x_uart_port
),
652 up
->clk
= devm_clk_get(&pdev
->dev
, "uart");
653 if (IS_ERR(up
->clk
)) {
654 dev_err(&pdev
->dev
, "unable to get UART clock\n");
655 return PTR_ERR(up
->clk
);
660 mem_res
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
661 port
->membase
= devm_ioremap_resource(&pdev
->dev
, mem_res
);
662 if (IS_ERR(port
->membase
))
663 return PTR_ERR(port
->membase
);
665 ret
= clk_prepare_enable(up
->clk
);
669 port
->uartclk
= clk_get_rate(up
->clk
);
670 if (!port
->uartclk
) {
672 goto err_disable_clk
;
675 port
->mapbase
= mem_res
->start
;
677 port
->irq
= irq_res
->start
;
678 port
->dev
= &pdev
->dev
;
679 port
->type
= PORT_AR933X
;
680 port
->iotype
= UPIO_MEM32
;
683 port
->fifosize
= AR933X_UART_FIFO_SIZE
;
684 port
->ops
= &ar933x_uart_ops
;
686 baud
= ar933x_uart_get_baud(port
->uartclk
, AR933X_UART_MAX_SCALE
, 1);
687 up
->min_baud
= max_t(unsigned int, baud
, AR933X_UART_MIN_BAUD
);
689 baud
= ar933x_uart_get_baud(port
->uartclk
, 0, AR933X_UART_MAX_STEP
);
690 up
->max_baud
= min_t(unsigned int, baud
, AR933X_UART_MAX_BAUD
);
692 ar933x_uart_add_console_port(up
);
694 ret
= uart_add_one_port(&ar933x_uart_driver
, &up
->port
);
696 goto err_disable_clk
;
698 platform_set_drvdata(pdev
, up
);
702 clk_disable_unprepare(up
->clk
);
706 static int ar933x_uart_remove(struct platform_device
*pdev
)
708 struct ar933x_uart_port
*up
;
710 up
= platform_get_drvdata(pdev
);
713 uart_remove_one_port(&ar933x_uart_driver
, &up
->port
);
714 clk_disable_unprepare(up
->clk
);
720 static struct platform_driver ar933x_uart_platform_driver
= {
721 .probe
= ar933x_uart_probe
,
722 .remove
= ar933x_uart_remove
,
725 .owner
= THIS_MODULE
,
729 static int __init
ar933x_uart_init(void)
733 ar933x_uart_driver
.nr
= CONFIG_SERIAL_AR933X_NR_UARTS
;
734 ret
= uart_register_driver(&ar933x_uart_driver
);
738 ret
= platform_driver_register(&ar933x_uart_platform_driver
);
740 goto err_unregister_uart_driver
;
744 err_unregister_uart_driver
:
745 uart_unregister_driver(&ar933x_uart_driver
);
750 static void __exit
ar933x_uart_exit(void)
752 platform_driver_unregister(&ar933x_uart_platform_driver
);
753 uart_unregister_driver(&ar933x_uart_driver
);
756 module_init(ar933x_uart_init
);
757 module_exit(ar933x_uart_exit
);
759 MODULE_DESCRIPTION("Atheros AR933X UART driver");
760 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
761 MODULE_LICENSE("GPL v2");
762 MODULE_ALIAS("platform:" DRIVER_NAME
);