2 * Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
4 * Based on msm_serial.c, which is:
5 * Copyright (C) 2007 Google, Inc.
6 * Author: Robert Love <rlove@google.com>
8 * This software is licensed under the terms of the GNU General Public
9 * License version 2, as published by the Free Software Foundation, and
10 * may be copied, distributed, and modified under those terms.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
18 #if defined(CONFIG_SERIAL_VT8500_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
19 # define SUPPORT_SYSRQ
22 #include <linux/hrtimer.h>
23 #include <linux/delay.h>
24 #include <linux/module.h>
26 #include <linux/ioport.h>
27 #include <linux/irq.h>
28 #include <linux/init.h>
29 #include <linux/console.h>
30 #include <linux/tty.h>
31 #include <linux/tty_flip.h>
32 #include <linux/serial_core.h>
33 #include <linux/serial.h>
34 #include <linux/slab.h>
35 #include <linux/clk.h>
36 #include <linux/platform_device.h>
40 * UART Register offsets
43 #define VT8500_URTDR 0x0000 /* Transmit data */
44 #define VT8500_URRDR 0x0004 /* Receive data */
45 #define VT8500_URDIV 0x0008 /* Clock/Baud rate divisor */
46 #define VT8500_URLCR 0x000C /* Line control */
47 #define VT8500_URICR 0x0010 /* IrDA control */
48 #define VT8500_URIER 0x0014 /* Interrupt enable */
49 #define VT8500_URISR 0x0018 /* Interrupt status */
50 #define VT8500_URUSR 0x001c /* UART status */
51 #define VT8500_URFCR 0x0020 /* FIFO control */
52 #define VT8500_URFIDX 0x0024 /* FIFO index */
53 #define VT8500_URBKR 0x0028 /* Break signal count */
54 #define VT8500_URTOD 0x002c /* Time out divisor */
55 #define VT8500_TXFIFO 0x1000 /* Transmit FIFO (16x8) */
56 #define VT8500_RXFIFO 0x1020 /* Receive FIFO (16x10) */
59 * Interrupt enable and status bits
62 #define TXDE (1 << 0) /* Tx Data empty */
63 #define RXDF (1 << 1) /* Rx Data full */
64 #define TXFAE (1 << 2) /* Tx FIFO almost empty */
65 #define TXFE (1 << 3) /* Tx FIFO empty */
66 #define RXFAF (1 << 4) /* Rx FIFO almost full */
67 #define RXFF (1 << 5) /* Rx FIFO full */
68 #define TXUDR (1 << 6) /* Tx underrun */
69 #define RXOVER (1 << 7) /* Rx overrun */
70 #define PER (1 << 8) /* Parity error */
71 #define FER (1 << 9) /* Frame error */
72 #define TCTS (1 << 10) /* Toggle of CTS */
73 #define RXTOUT (1 << 11) /* Rx timeout */
74 #define BKDONE (1 << 12) /* Break signal done */
75 #define ERR (1 << 13) /* AHB error response */
77 #define RX_FIFO_INTS (RXFAF | RXFF | RXOVER | PER | FER | RXTOUT)
78 #define TX_FIFO_INTS (TXFAE | TXFE | TXUDR)
80 #define VT8500_MAX_PORTS 6
83 struct uart_port uart
;
90 * we use this variable to keep track of which ports
91 * have been allocated as we can't use pdev->id in
94 static unsigned long vt8500_ports_in_use
;
96 static inline void vt8500_write(struct uart_port
*port
, unsigned int val
,
99 writel(val
, port
->membase
+ off
);
102 static inline unsigned int vt8500_read(struct uart_port
*port
, unsigned int off
)
104 return readl(port
->membase
+ off
);
107 static void vt8500_stop_tx(struct uart_port
*port
)
109 struct vt8500_port
*vt8500_port
= container_of(port
,
113 vt8500_port
->ier
&= ~TX_FIFO_INTS
;
114 vt8500_write(port
, vt8500_port
->ier
, VT8500_URIER
);
117 static void vt8500_stop_rx(struct uart_port
*port
)
119 struct vt8500_port
*vt8500_port
= container_of(port
,
123 vt8500_port
->ier
&= ~RX_FIFO_INTS
;
124 vt8500_write(port
, vt8500_port
->ier
, VT8500_URIER
);
127 static void vt8500_enable_ms(struct uart_port
*port
)
129 struct vt8500_port
*vt8500_port
= container_of(port
,
133 vt8500_port
->ier
|= TCTS
;
134 vt8500_write(port
, vt8500_port
->ier
, VT8500_URIER
);
137 static void handle_rx(struct uart_port
*port
)
139 struct tty_port
*tport
= &port
->state
->port
;
144 if ((vt8500_read(port
, VT8500_URISR
) & RXOVER
)) {
145 port
->icount
.overrun
++;
146 tty_insert_flip_char(tport
, 0, TTY_OVERRUN
);
149 /* and now the main RX loop */
150 while (vt8500_read(port
, VT8500_URFIDX
) & 0x1f00) {
152 char flag
= TTY_NORMAL
;
154 c
= readw(port
->membase
+ VT8500_RXFIFO
) & 0x3ff;
156 /* Mask conditions we're ignorning. */
157 c
&= ~port
->read_status_mask
;
160 port
->icount
.frame
++;
162 } else if (c
& PER
) {
163 port
->icount
.parity
++;
168 if (!uart_handle_sysrq_char(port
, c
))
169 tty_insert_flip_char(tport
, c
, flag
);
172 tty_flip_buffer_push(tport
);
175 static void handle_tx(struct uart_port
*port
)
177 struct circ_buf
*xmit
= &port
->state
->xmit
;
180 writeb(port
->x_char
, port
->membase
+ VT8500_TXFIFO
);
184 if (uart_circ_empty(xmit
) || uart_tx_stopped(port
)) {
185 vt8500_stop_tx(port
);
189 while ((vt8500_read(port
, VT8500_URFIDX
) & 0x1f) < 16) {
190 if (uart_circ_empty(xmit
))
193 writeb(xmit
->buf
[xmit
->tail
], port
->membase
+ VT8500_TXFIFO
);
195 xmit
->tail
= (xmit
->tail
+ 1) & (UART_XMIT_SIZE
- 1);
199 if (uart_circ_chars_pending(xmit
) < WAKEUP_CHARS
)
200 uart_write_wakeup(port
);
202 if (uart_circ_empty(xmit
))
203 vt8500_stop_tx(port
);
206 static void vt8500_start_tx(struct uart_port
*port
)
208 struct vt8500_port
*vt8500_port
= container_of(port
,
212 vt8500_port
->ier
&= ~TX_FIFO_INTS
;
213 vt8500_write(port
, vt8500_port
->ier
, VT8500_URIER
);
215 vt8500_port
->ier
|= TX_FIFO_INTS
;
216 vt8500_write(port
, vt8500_port
->ier
, VT8500_URIER
);
219 static void handle_delta_cts(struct uart_port
*port
)
222 wake_up_interruptible(&port
->state
->port
.delta_msr_wait
);
225 static irqreturn_t
vt8500_irq(int irq
, void *dev_id
)
227 struct uart_port
*port
= dev_id
;
230 spin_lock(&port
->lock
);
231 isr
= vt8500_read(port
, VT8500_URISR
);
233 /* Acknowledge active status bits */
234 vt8500_write(port
, isr
, VT8500_URISR
);
236 if (isr
& RX_FIFO_INTS
)
238 if (isr
& TX_FIFO_INTS
)
241 handle_delta_cts(port
);
243 spin_unlock(&port
->lock
);
248 static unsigned int vt8500_tx_empty(struct uart_port
*port
)
250 return (vt8500_read(port
, VT8500_URFIDX
) & 0x1f) < 16 ?
254 static unsigned int vt8500_get_mctrl(struct uart_port
*port
)
258 usr
= vt8500_read(port
, VT8500_URUSR
);
265 static void vt8500_set_mctrl(struct uart_port
*port
, unsigned int mctrl
)
269 static void vt8500_break_ctl(struct uart_port
*port
, int break_ctl
)
272 vt8500_write(port
, vt8500_read(port
, VT8500_URLCR
) | (1 << 9),
276 static int vt8500_set_baud_rate(struct uart_port
*port
, unsigned int baud
)
279 unsigned int loops
= 1000;
281 div
= vt8500_read(port
, VT8500_URDIV
) & ~(0x3ff);
283 if (unlikely((baud
< 900) || (baud
> 921600)))
286 div
|= (921600 / baud
) - 1;
288 while ((vt8500_read(port
, VT8500_URUSR
) & (1 << 5)) && --loops
)
290 vt8500_write(port
, div
, VT8500_URDIV
);
295 static int vt8500_startup(struct uart_port
*port
)
297 struct vt8500_port
*vt8500_port
=
298 container_of(port
, struct vt8500_port
, uart
);
301 snprintf(vt8500_port
->name
, sizeof(vt8500_port
->name
),
302 "vt8500_serial%d", port
->line
);
304 ret
= request_irq(port
->irq
, vt8500_irq
, IRQF_TRIGGER_HIGH
,
305 vt8500_port
->name
, port
);
309 vt8500_write(port
, 0x03, VT8500_URLCR
); /* enable TX & RX */
314 static void vt8500_shutdown(struct uart_port
*port
)
316 struct vt8500_port
*vt8500_port
=
317 container_of(port
, struct vt8500_port
, uart
);
319 vt8500_port
->ier
= 0;
321 /* disable interrupts and FIFOs */
322 vt8500_write(&vt8500_port
->uart
, 0, VT8500_URIER
);
323 vt8500_write(&vt8500_port
->uart
, 0x880, VT8500_URFCR
);
324 free_irq(port
->irq
, port
);
327 static void vt8500_set_termios(struct uart_port
*port
,
328 struct ktermios
*termios
,
329 struct ktermios
*old
)
331 struct vt8500_port
*vt8500_port
=
332 container_of(port
, struct vt8500_port
, uart
);
334 unsigned int baud
, lcr
;
335 unsigned int loops
= 1000;
337 spin_lock_irqsave(&port
->lock
, flags
);
339 /* calculate and set baud rate */
340 baud
= uart_get_baud_rate(port
, termios
, old
, 900, 921600);
341 baud
= vt8500_set_baud_rate(port
, baud
);
342 if (tty_termios_baud_rate(termios
))
343 tty_termios_encode_baud_rate(termios
, baud
, baud
);
345 /* calculate parity */
346 lcr
= vt8500_read(&vt8500_port
->uart
, VT8500_URLCR
);
347 lcr
&= ~((1 << 5) | (1 << 4));
348 if (termios
->c_cflag
& PARENB
) {
350 termios
->c_cflag
&= ~CMSPAR
;
351 if (termios
->c_cflag
& PARODD
)
355 /* calculate bits per char */
357 switch (termios
->c_cflag
& CSIZE
) {
363 termios
->c_cflag
&= ~CSIZE
;
364 termios
->c_cflag
|= CS8
;
368 /* calculate stop bits */
370 if (termios
->c_cflag
& CSTOPB
)
373 /* set parity, bits per char, and stop bit */
374 vt8500_write(&vt8500_port
->uart
, lcr
, VT8500_URLCR
);
376 /* Configure status bits to ignore based on termio flags. */
377 port
->read_status_mask
= 0;
378 if (termios
->c_iflag
& IGNPAR
)
379 port
->read_status_mask
= FER
| PER
;
381 uart_update_timeout(port
, termios
->c_cflag
, baud
);
384 vt8500_write(&vt8500_port
->uart
, 0x88c, VT8500_URFCR
);
385 while ((vt8500_read(&vt8500_port
->uart
, VT8500_URFCR
) & 0xc)
389 /* Every possible FIFO-related interrupt */
390 vt8500_port
->ier
= RX_FIFO_INTS
| TX_FIFO_INTS
;
395 if (UART_ENABLE_MS(&vt8500_port
->uart
, termios
->c_cflag
))
396 vt8500_port
->ier
|= TCTS
;
398 vt8500_write(&vt8500_port
->uart
, 0x881, VT8500_URFCR
);
399 vt8500_write(&vt8500_port
->uart
, vt8500_port
->ier
, VT8500_URIER
);
401 spin_unlock_irqrestore(&port
->lock
, flags
);
404 static const char *vt8500_type(struct uart_port
*port
)
406 struct vt8500_port
*vt8500_port
=
407 container_of(port
, struct vt8500_port
, uart
);
408 return vt8500_port
->name
;
411 static void vt8500_release_port(struct uart_port
*port
)
415 static int vt8500_request_port(struct uart_port
*port
)
420 static void vt8500_config_port(struct uart_port
*port
, int flags
)
422 port
->type
= PORT_VT8500
;
425 static int vt8500_verify_port(struct uart_port
*port
,
426 struct serial_struct
*ser
)
428 if (unlikely(ser
->type
!= PORT_UNKNOWN
&& ser
->type
!= PORT_VT8500
))
430 if (unlikely(port
->irq
!= ser
->irq
))
435 static struct vt8500_port
*vt8500_uart_ports
[VT8500_MAX_PORTS
];
436 static struct uart_driver vt8500_uart_driver
;
438 #ifdef CONFIG_SERIAL_VT8500_CONSOLE
440 static inline void wait_for_xmitr(struct uart_port
*port
)
442 unsigned int status
, tmout
= 10000;
444 /* Wait up to 10ms for the character(s) to be sent. */
446 status
= vt8500_read(port
, VT8500_URFIDX
);
451 } while (status
& 0x10);
454 static void vt8500_console_putchar(struct uart_port
*port
, int c
)
456 wait_for_xmitr(port
);
457 writeb(c
, port
->membase
+ VT8500_TXFIFO
);
460 static void vt8500_console_write(struct console
*co
, const char *s
,
463 struct vt8500_port
*vt8500_port
= vt8500_uart_ports
[co
->index
];
466 BUG_ON(co
->index
< 0 || co
->index
>= vt8500_uart_driver
.nr
);
468 ier
= vt8500_read(&vt8500_port
->uart
, VT8500_URIER
);
469 vt8500_write(&vt8500_port
->uart
, VT8500_URIER
, 0);
471 uart_console_write(&vt8500_port
->uart
, s
, count
,
472 vt8500_console_putchar
);
475 * Finally, wait for transmitter to become empty
476 * and switch back to FIFO
478 wait_for_xmitr(&vt8500_port
->uart
);
479 vt8500_write(&vt8500_port
->uart
, VT8500_URIER
, ier
);
482 static int __init
vt8500_console_setup(struct console
*co
, char *options
)
484 struct vt8500_port
*vt8500_port
;
490 if (unlikely(co
->index
>= vt8500_uart_driver
.nr
|| co
->index
< 0))
493 vt8500_port
= vt8500_uart_ports
[co
->index
];
499 uart_parse_options(options
, &baud
, &parity
, &bits
, &flow
);
501 return uart_set_options(&vt8500_port
->uart
,
502 co
, baud
, parity
, bits
, flow
);
505 static struct console vt8500_console
= {
507 .write
= vt8500_console_write
,
508 .device
= uart_console_device
,
509 .setup
= vt8500_console_setup
,
510 .flags
= CON_PRINTBUFFER
,
512 .data
= &vt8500_uart_driver
,
515 #define VT8500_CONSOLE (&vt8500_console)
518 #define VT8500_CONSOLE NULL
521 static struct uart_ops vt8500_uart_pops
= {
522 .tx_empty
= vt8500_tx_empty
,
523 .set_mctrl
= vt8500_set_mctrl
,
524 .get_mctrl
= vt8500_get_mctrl
,
525 .stop_tx
= vt8500_stop_tx
,
526 .start_tx
= vt8500_start_tx
,
527 .stop_rx
= vt8500_stop_rx
,
528 .enable_ms
= vt8500_enable_ms
,
529 .break_ctl
= vt8500_break_ctl
,
530 .startup
= vt8500_startup
,
531 .shutdown
= vt8500_shutdown
,
532 .set_termios
= vt8500_set_termios
,
534 .release_port
= vt8500_release_port
,
535 .request_port
= vt8500_request_port
,
536 .config_port
= vt8500_config_port
,
537 .verify_port
= vt8500_verify_port
,
540 static struct uart_driver vt8500_uart_driver
= {
541 .owner
= THIS_MODULE
,
542 .driver_name
= "vt8500_serial",
543 .dev_name
= "ttyWMT",
545 .cons
= VT8500_CONSOLE
,
548 static int vt8500_serial_probe(struct platform_device
*pdev
)
550 struct vt8500_port
*vt8500_port
;
551 struct resource
*mmres
, *irqres
;
552 struct device_node
*np
= pdev
->dev
.of_node
;
556 mmres
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
557 irqres
= platform_get_resource(pdev
, IORESOURCE_IRQ
, 0);
558 if (!mmres
|| !irqres
)
562 port
= of_alias_get_id(np
, "serial");
563 if (port
>= VT8500_MAX_PORTS
)
569 /* calculate the port id */
570 port
= find_first_zero_bit(&vt8500_ports_in_use
,
571 sizeof(vt8500_ports_in_use
));
574 if (port
>= VT8500_MAX_PORTS
)
577 /* reserve the port id */
578 if (test_and_set_bit(port
, &vt8500_ports_in_use
)) {
579 /* port already in use - shouldn't really happen */
583 vt8500_port
= devm_kzalloc(&pdev
->dev
, sizeof(struct vt8500_port
),
588 vt8500_port
->uart
.membase
= devm_request_and_ioremap(&pdev
->dev
, mmres
);
589 if (!vt8500_port
->uart
.membase
)
590 return -EADDRNOTAVAIL
;
592 vt8500_port
->clk
= of_clk_get(pdev
->dev
.of_node
, 0);
593 if (IS_ERR(vt8500_port
->clk
)) {
594 dev_err(&pdev
->dev
, "failed to get clock\n");
598 ret
= clk_prepare_enable(vt8500_port
->clk
);
600 dev_err(&pdev
->dev
, "failed to enable clock\n");
604 vt8500_port
->uart
.type
= PORT_VT8500
;
605 vt8500_port
->uart
.iotype
= UPIO_MEM
;
606 vt8500_port
->uart
.mapbase
= mmres
->start
;
607 vt8500_port
->uart
.irq
= irqres
->start
;
608 vt8500_port
->uart
.fifosize
= 16;
609 vt8500_port
->uart
.ops
= &vt8500_uart_pops
;
610 vt8500_port
->uart
.line
= port
;
611 vt8500_port
->uart
.dev
= &pdev
->dev
;
612 vt8500_port
->uart
.flags
= UPF_IOREMAP
| UPF_BOOT_AUTOCONF
;
614 vt8500_port
->uart
.uartclk
= clk_get_rate(vt8500_port
->clk
);
616 snprintf(vt8500_port
->name
, sizeof(vt8500_port
->name
),
617 "VT8500 UART%d", pdev
->id
);
619 vt8500_uart_ports
[port
] = vt8500_port
;
621 uart_add_one_port(&vt8500_uart_driver
, &vt8500_port
->uart
);
623 platform_set_drvdata(pdev
, vt8500_port
);
628 static int vt8500_serial_remove(struct platform_device
*pdev
)
630 struct vt8500_port
*vt8500_port
= platform_get_drvdata(pdev
);
632 platform_set_drvdata(pdev
, NULL
);
633 clk_disable_unprepare(vt8500_port
->clk
);
634 uart_remove_one_port(&vt8500_uart_driver
, &vt8500_port
->uart
);
639 static const struct of_device_id wmt_dt_ids
[] = {
640 { .compatible
= "via,vt8500-uart", },
644 static struct platform_driver vt8500_platform_driver
= {
645 .probe
= vt8500_serial_probe
,
646 .remove
= vt8500_serial_remove
,
648 .name
= "vt8500_serial",
649 .owner
= THIS_MODULE
,
650 .of_match_table
= of_match_ptr(wmt_dt_ids
),
654 static int __init
vt8500_serial_init(void)
658 ret
= uart_register_driver(&vt8500_uart_driver
);
662 ret
= platform_driver_register(&vt8500_platform_driver
);
665 uart_unregister_driver(&vt8500_uart_driver
);
670 static void __exit
vt8500_serial_exit(void)
672 #ifdef CONFIG_SERIAL_VT8500_CONSOLE
673 unregister_console(&vt8500_console
);
675 platform_driver_unregister(&vt8500_platform_driver
);
676 uart_unregister_driver(&vt8500_uart_driver
);
679 module_init(vt8500_serial_init
);
680 module_exit(vt8500_serial_exit
);
682 MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
683 MODULE_DESCRIPTION("Driver for vt8500 serial device");
684 MODULE_LICENSE("GPL v2");