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_struct
*tty
= tty_port_tty_get(&port
->state
->port
);
141 /* Discard data: no tty available */
142 int count
= (vt8500_read(port
, VT8500_URFIDX
) & 0x1f00) >> 8;
145 ch
= readw(port
->membase
+ VT8500_RXFIFO
);
152 if ((vt8500_read(port
, VT8500_URISR
) & RXOVER
)) {
153 port
->icount
.overrun
++;
154 tty_insert_flip_char(tty
, 0, TTY_OVERRUN
);
157 /* and now the main RX loop */
158 while (vt8500_read(port
, VT8500_URFIDX
) & 0x1f00) {
160 char flag
= TTY_NORMAL
;
162 c
= readw(port
->membase
+ VT8500_RXFIFO
) & 0x3ff;
164 /* Mask conditions we're ignorning. */
165 c
&= ~port
->read_status_mask
;
168 port
->icount
.frame
++;
170 } else if (c
& PER
) {
171 port
->icount
.parity
++;
176 if (!uart_handle_sysrq_char(port
, c
))
177 tty_insert_flip_char(tty
, c
, flag
);
180 tty_flip_buffer_push(tty
);
184 static void handle_tx(struct uart_port
*port
)
186 struct circ_buf
*xmit
= &port
->state
->xmit
;
189 writeb(port
->x_char
, port
->membase
+ VT8500_TXFIFO
);
193 if (uart_circ_empty(xmit
) || uart_tx_stopped(port
)) {
194 vt8500_stop_tx(port
);
198 while ((vt8500_read(port
, VT8500_URFIDX
) & 0x1f) < 16) {
199 if (uart_circ_empty(xmit
))
202 writeb(xmit
->buf
[xmit
->tail
], port
->membase
+ VT8500_TXFIFO
);
204 xmit
->tail
= (xmit
->tail
+ 1) & (UART_XMIT_SIZE
- 1);
208 if (uart_circ_chars_pending(xmit
) < WAKEUP_CHARS
)
209 uart_write_wakeup(port
);
211 if (uart_circ_empty(xmit
))
212 vt8500_stop_tx(port
);
215 static void vt8500_start_tx(struct uart_port
*port
)
217 struct vt8500_port
*vt8500_port
= container_of(port
,
221 vt8500_port
->ier
&= ~TX_FIFO_INTS
;
222 vt8500_write(port
, vt8500_port
->ier
, VT8500_URIER
);
224 vt8500_port
->ier
|= TX_FIFO_INTS
;
225 vt8500_write(port
, vt8500_port
->ier
, VT8500_URIER
);
228 static void handle_delta_cts(struct uart_port
*port
)
231 wake_up_interruptible(&port
->state
->port
.delta_msr_wait
);
234 static irqreturn_t
vt8500_irq(int irq
, void *dev_id
)
236 struct uart_port
*port
= dev_id
;
239 spin_lock(&port
->lock
);
240 isr
= vt8500_read(port
, VT8500_URISR
);
242 /* Acknowledge active status bits */
243 vt8500_write(port
, isr
, VT8500_URISR
);
245 if (isr
& RX_FIFO_INTS
)
247 if (isr
& TX_FIFO_INTS
)
250 handle_delta_cts(port
);
252 spin_unlock(&port
->lock
);
257 static unsigned int vt8500_tx_empty(struct uart_port
*port
)
259 return (vt8500_read(port
, VT8500_URFIDX
) & 0x1f) < 16 ?
263 static unsigned int vt8500_get_mctrl(struct uart_port
*port
)
267 usr
= vt8500_read(port
, VT8500_URUSR
);
274 static void vt8500_set_mctrl(struct uart_port
*port
, unsigned int mctrl
)
278 static void vt8500_break_ctl(struct uart_port
*port
, int break_ctl
)
281 vt8500_write(port
, vt8500_read(port
, VT8500_URLCR
) | (1 << 9),
285 static int vt8500_set_baud_rate(struct uart_port
*port
, unsigned int baud
)
288 unsigned int loops
= 1000;
290 div
= vt8500_read(port
, VT8500_URDIV
) & ~(0x3ff);
292 if (unlikely((baud
< 900) || (baud
> 921600)))
295 div
|= (921600 / baud
) - 1;
297 while ((vt8500_read(port
, VT8500_URUSR
) & (1 << 5)) && --loops
)
299 vt8500_write(port
, div
, VT8500_URDIV
);
304 static int vt8500_startup(struct uart_port
*port
)
306 struct vt8500_port
*vt8500_port
=
307 container_of(port
, struct vt8500_port
, uart
);
310 snprintf(vt8500_port
->name
, sizeof(vt8500_port
->name
),
311 "vt8500_serial%d", port
->line
);
313 ret
= request_irq(port
->irq
, vt8500_irq
, IRQF_TRIGGER_HIGH
,
314 vt8500_port
->name
, port
);
318 vt8500_write(port
, 0x03, VT8500_URLCR
); /* enable TX & RX */
323 static void vt8500_shutdown(struct uart_port
*port
)
325 struct vt8500_port
*vt8500_port
=
326 container_of(port
, struct vt8500_port
, uart
);
328 vt8500_port
->ier
= 0;
330 /* disable interrupts and FIFOs */
331 vt8500_write(&vt8500_port
->uart
, 0, VT8500_URIER
);
332 vt8500_write(&vt8500_port
->uart
, 0x880, VT8500_URFCR
);
333 free_irq(port
->irq
, port
);
336 static void vt8500_set_termios(struct uart_port
*port
,
337 struct ktermios
*termios
,
338 struct ktermios
*old
)
340 struct vt8500_port
*vt8500_port
=
341 container_of(port
, struct vt8500_port
, uart
);
343 unsigned int baud
, lcr
;
344 unsigned int loops
= 1000;
346 spin_lock_irqsave(&port
->lock
, flags
);
348 /* calculate and set baud rate */
349 baud
= uart_get_baud_rate(port
, termios
, old
, 900, 921600);
350 baud
= vt8500_set_baud_rate(port
, baud
);
351 if (tty_termios_baud_rate(termios
))
352 tty_termios_encode_baud_rate(termios
, baud
, baud
);
354 /* calculate parity */
355 lcr
= vt8500_read(&vt8500_port
->uart
, VT8500_URLCR
);
356 lcr
&= ~((1 << 5) | (1 << 4));
357 if (termios
->c_cflag
& PARENB
) {
359 termios
->c_cflag
&= ~CMSPAR
;
360 if (termios
->c_cflag
& PARODD
)
364 /* calculate bits per char */
366 switch (termios
->c_cflag
& CSIZE
) {
372 termios
->c_cflag
&= ~CSIZE
;
373 termios
->c_cflag
|= CS8
;
377 /* calculate stop bits */
379 if (termios
->c_cflag
& CSTOPB
)
382 /* set parity, bits per char, and stop bit */
383 vt8500_write(&vt8500_port
->uart
, lcr
, VT8500_URLCR
);
385 /* Configure status bits to ignore based on termio flags. */
386 port
->read_status_mask
= 0;
387 if (termios
->c_iflag
& IGNPAR
)
388 port
->read_status_mask
= FER
| PER
;
390 uart_update_timeout(port
, termios
->c_cflag
, baud
);
393 vt8500_write(&vt8500_port
->uart
, 0x88c, VT8500_URFCR
);
394 while ((vt8500_read(&vt8500_port
->uart
, VT8500_URFCR
) & 0xc)
398 /* Every possible FIFO-related interrupt */
399 vt8500_port
->ier
= RX_FIFO_INTS
| TX_FIFO_INTS
;
404 if (UART_ENABLE_MS(&vt8500_port
->uart
, termios
->c_cflag
))
405 vt8500_port
->ier
|= TCTS
;
407 vt8500_write(&vt8500_port
->uart
, 0x881, VT8500_URFCR
);
408 vt8500_write(&vt8500_port
->uart
, vt8500_port
->ier
, VT8500_URIER
);
410 spin_unlock_irqrestore(&port
->lock
, flags
);
413 static const char *vt8500_type(struct uart_port
*port
)
415 struct vt8500_port
*vt8500_port
=
416 container_of(port
, struct vt8500_port
, uart
);
417 return vt8500_port
->name
;
420 static void vt8500_release_port(struct uart_port
*port
)
424 static int vt8500_request_port(struct uart_port
*port
)
429 static void vt8500_config_port(struct uart_port
*port
, int flags
)
431 port
->type
= PORT_VT8500
;
434 static int vt8500_verify_port(struct uart_port
*port
,
435 struct serial_struct
*ser
)
437 if (unlikely(ser
->type
!= PORT_UNKNOWN
&& ser
->type
!= PORT_VT8500
))
439 if (unlikely(port
->irq
!= ser
->irq
))
444 static struct vt8500_port
*vt8500_uart_ports
[VT8500_MAX_PORTS
];
445 static struct uart_driver vt8500_uart_driver
;
447 #ifdef CONFIG_SERIAL_VT8500_CONSOLE
449 static inline void wait_for_xmitr(struct uart_port
*port
)
451 unsigned int status
, tmout
= 10000;
453 /* Wait up to 10ms for the character(s) to be sent. */
455 status
= vt8500_read(port
, VT8500_URFIDX
);
460 } while (status
& 0x10);
463 static void vt8500_console_putchar(struct uart_port
*port
, int c
)
465 wait_for_xmitr(port
);
466 writeb(c
, port
->membase
+ VT8500_TXFIFO
);
469 static void vt8500_console_write(struct console
*co
, const char *s
,
472 struct vt8500_port
*vt8500_port
= vt8500_uart_ports
[co
->index
];
475 BUG_ON(co
->index
< 0 || co
->index
>= vt8500_uart_driver
.nr
);
477 ier
= vt8500_read(&vt8500_port
->uart
, VT8500_URIER
);
478 vt8500_write(&vt8500_port
->uart
, VT8500_URIER
, 0);
480 uart_console_write(&vt8500_port
->uart
, s
, count
,
481 vt8500_console_putchar
);
484 * Finally, wait for transmitter to become empty
485 * and switch back to FIFO
487 wait_for_xmitr(&vt8500_port
->uart
);
488 vt8500_write(&vt8500_port
->uart
, VT8500_URIER
, ier
);
491 static int __init
vt8500_console_setup(struct console
*co
, char *options
)
493 struct vt8500_port
*vt8500_port
;
499 if (unlikely(co
->index
>= vt8500_uart_driver
.nr
|| co
->index
< 0))
502 vt8500_port
= vt8500_uart_ports
[co
->index
];
508 uart_parse_options(options
, &baud
, &parity
, &bits
, &flow
);
510 return uart_set_options(&vt8500_port
->uart
,
511 co
, baud
, parity
, bits
, flow
);
514 static struct console vt8500_console
= {
516 .write
= vt8500_console_write
,
517 .device
= uart_console_device
,
518 .setup
= vt8500_console_setup
,
519 .flags
= CON_PRINTBUFFER
,
521 .data
= &vt8500_uart_driver
,
524 #define VT8500_CONSOLE (&vt8500_console)
527 #define VT8500_CONSOLE NULL
530 static struct uart_ops vt8500_uart_pops
= {
531 .tx_empty
= vt8500_tx_empty
,
532 .set_mctrl
= vt8500_set_mctrl
,
533 .get_mctrl
= vt8500_get_mctrl
,
534 .stop_tx
= vt8500_stop_tx
,
535 .start_tx
= vt8500_start_tx
,
536 .stop_rx
= vt8500_stop_rx
,
537 .enable_ms
= vt8500_enable_ms
,
538 .break_ctl
= vt8500_break_ctl
,
539 .startup
= vt8500_startup
,
540 .shutdown
= vt8500_shutdown
,
541 .set_termios
= vt8500_set_termios
,
543 .release_port
= vt8500_release_port
,
544 .request_port
= vt8500_request_port
,
545 .config_port
= vt8500_config_port
,
546 .verify_port
= vt8500_verify_port
,
549 static struct uart_driver vt8500_uart_driver
= {
550 .owner
= THIS_MODULE
,
551 .driver_name
= "vt8500_serial",
552 .dev_name
= "ttyWMT",
554 .cons
= VT8500_CONSOLE
,
557 static int __devinit
vt8500_serial_probe(struct platform_device
*pdev
)
559 struct vt8500_port
*vt8500_port
;
560 struct resource
*mmres
, *irqres
;
561 struct device_node
*np
= pdev
->dev
.of_node
;
565 mmres
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
566 irqres
= platform_get_resource(pdev
, IORESOURCE_IRQ
, 0);
567 if (!mmres
|| !irqres
)
570 vt8500_port
= kzalloc(sizeof(struct vt8500_port
), GFP_KERNEL
);
575 port
= of_alias_get_id(np
, "serial");
576 if (port
> VT8500_MAX_PORTS
)
582 /* calculate the port id */
583 port
= find_first_zero_bit(&vt8500_ports_in_use
,
584 sizeof(vt8500_ports_in_use
));
587 if (port
> VT8500_MAX_PORTS
)
590 /* reserve the port id */
591 if (test_and_set_bit(port
, &vt8500_ports_in_use
)) {
592 /* port already in use - shouldn't really happen */
596 vt8500_port
->uart
.type
= PORT_VT8500
;
597 vt8500_port
->uart
.iotype
= UPIO_MEM
;
598 vt8500_port
->uart
.mapbase
= mmres
->start
;
599 vt8500_port
->uart
.irq
= irqres
->start
;
600 vt8500_port
->uart
.fifosize
= 16;
601 vt8500_port
->uart
.ops
= &vt8500_uart_pops
;
602 vt8500_port
->uart
.line
= port
;
603 vt8500_port
->uart
.dev
= &pdev
->dev
;
604 vt8500_port
->uart
.flags
= UPF_IOREMAP
| UPF_BOOT_AUTOCONF
;
606 vt8500_port
->clk
= of_clk_get(pdev
->dev
.of_node
, 0);
607 if (vt8500_port
->clk
) {
608 vt8500_port
->uart
.uartclk
= clk_get_rate(vt8500_port
->clk
);
610 /* use the default of 24Mhz if not specified and warn */
611 pr_warn("%s: serial clock source not specified\n", __func__
);
612 vt8500_port
->uart
.uartclk
= 24000000;
615 snprintf(vt8500_port
->name
, sizeof(vt8500_port
->name
),
616 "VT8500 UART%d", pdev
->id
);
618 vt8500_port
->uart
.membase
= ioremap(mmres
->start
, resource_size(mmres
));
619 if (!vt8500_port
->uart
.membase
) {
624 vt8500_uart_ports
[port
] = vt8500_port
;
626 uart_add_one_port(&vt8500_uart_driver
, &vt8500_port
->uart
);
628 platform_set_drvdata(pdev
, vt8500_port
);
637 static int __devexit
vt8500_serial_remove(struct platform_device
*pdev
)
639 struct vt8500_port
*vt8500_port
= platform_get_drvdata(pdev
);
641 platform_set_drvdata(pdev
, NULL
);
642 uart_remove_one_port(&vt8500_uart_driver
, &vt8500_port
->uart
);
648 static const struct of_device_id wmt_dt_ids
[] = {
649 { .compatible
= "via,vt8500-uart", },
653 static struct platform_driver vt8500_platform_driver
= {
654 .probe
= vt8500_serial_probe
,
655 .remove
= __devexit_p(vt8500_serial_remove
),
657 .name
= "vt8500_serial",
658 .owner
= THIS_MODULE
,
659 .of_match_table
= of_match_ptr(wmt_dt_ids
),
663 static int __init
vt8500_serial_init(void)
667 ret
= uart_register_driver(&vt8500_uart_driver
);
671 ret
= platform_driver_register(&vt8500_platform_driver
);
674 uart_unregister_driver(&vt8500_uart_driver
);
679 static void __exit
vt8500_serial_exit(void)
681 #ifdef CONFIG_SERIAL_VT8500_CONSOLE
682 unregister_console(&vt8500_console
);
684 platform_driver_unregister(&vt8500_platform_driver
);
685 uart_unregister_driver(&vt8500_uart_driver
);
688 module_init(vt8500_serial_init
);
689 module_exit(vt8500_serial_exit
);
691 MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
692 MODULE_DESCRIPTION("Driver for vt8500 serial device");
693 MODULE_LICENSE("GPL v2");