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)
571 port = of_alias_get_id(np, "serial");
572 if (port > VT8500_MAX_PORTS)
578 /* calculate the port id */
579 port = find_first_zero_bit(&vt8500_ports_in_use,
580 sizeof(vt8500_ports_in_use));
583 if (port > VT8500_MAX_PORTS)
586 /* reserve the port id */
587 if (test_and_set_bit(port, &vt8500_ports_in_use)) {
588 /* port already in use - shouldn't really happen */
592 vt8500_port = kzalloc(sizeof(struct vt8500_port), GFP_KERNEL);
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 = 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");