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 = kzalloc(sizeof(struct vt8500_port), GFP_KERNEL);
587 vt8500_port->uart.membase = devm_request_and_ioremap(&pdev->dev, mmres);
588 if (!vt8500_port->uart.membase)
589 return -EADDRNOTAVAIL;
591 vt8500_port->clk = of_clk_get(pdev->dev.of_node, 0);
592 if (IS_ERR(vt8500_port->clk)) {
593 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;
613 vt8500_port->uart.uartclk = clk_get_rate(vt8500_port->clk);
615 snprintf(vt8500_port->name, sizeof(vt8500_port->name),
616 "VT8500 UART%d", pdev->id);
618 vt8500_uart_ports[port] = vt8500_port;
620 uart_add_one_port(&vt8500_uart_driver, &vt8500_port->uart);
622 platform_set_drvdata(pdev, vt8500_port);
631 static int vt8500_serial_remove(struct platform_device *pdev)
633 struct vt8500_port *vt8500_port = platform_get_drvdata(pdev);
635 platform_set_drvdata(pdev, NULL);
636 clk_disable_unprepare(vt8500_port->clk);
637 uart_remove_one_port(&vt8500_uart_driver, &vt8500_port->uart);
643 static const struct of_device_id wmt_dt_ids[] = {
644 { .compatible = "via,vt8500-uart", },
648 static struct platform_driver vt8500_platform_driver = {
649 .probe = vt8500_serial_probe,
650 .remove = vt8500_serial_remove,
652 .name = "vt8500_serial",
653 .owner = THIS_MODULE,
654 .of_match_table = of_match_ptr(wmt_dt_ids),
658 static int __init vt8500_serial_init(void)
662 ret = uart_register_driver(&vt8500_uart_driver);
666 ret = platform_driver_register(&vt8500_platform_driver);
669 uart_unregister_driver(&vt8500_uart_driver);
674 static void __exit vt8500_serial_exit(void)
676 #ifdef CONFIG_SERIAL_VT8500_CONSOLE
677 unregister_console(&vt8500_console);
679 platform_driver_unregister(&vt8500_platform_driver);
680 uart_unregister_driver(&vt8500_uart_driver);
683 module_init(vt8500_serial_init);
684 module_exit(vt8500_serial_exit);
686 MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
687 MODULE_DESCRIPTION("Driver for vt8500 serial device");
688 MODULE_LICENSE("GPL v2");