2 * altera_uart.c -- Altera UART driver
4 * Based on mcf.c -- Freescale ColdFire UART driver
6 * (C) Copyright 2003-2007, Greg Ungerer <gerg@snapgear.com>
7 * (C) Copyright 2008, Thomas Chou <thomas@wytron.com.tw>
8 * (C) Copyright 2010, Tobias Klauser <tklauser@distanz.ch>
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
16 #include <linux/kernel.h>
17 #include <linux/init.h>
18 #include <linux/timer.h>
19 #include <linux/interrupt.h>
20 #include <linux/module.h>
21 #include <linux/console.h>
22 #include <linux/tty.h>
23 #include <linux/tty_flip.h>
24 #include <linux/serial.h>
25 #include <linux/serial_core.h>
26 #include <linux/platform_device.h>
29 #include <linux/altera_uart.h>
31 #define DRV_NAME "altera_uart"
32 #define SERIAL_ALTERA_MAJOR 204
33 #define SERIAL_ALTERA_MINOR 213
36 * Altera UART register definitions according to the Nios UART datasheet:
37 * http://www.altera.com/literature/ds/ds_nios_uart.pdf
40 #define ALTERA_UART_SIZE 32
42 #define ALTERA_UART_RXDATA_REG 0
43 #define ALTERA_UART_TXDATA_REG 4
44 #define ALTERA_UART_STATUS_REG 8
45 #define ALTERA_UART_CONTROL_REG 12
46 #define ALTERA_UART_DIVISOR_REG 16
47 #define ALTERA_UART_EOP_REG 20
49 #define ALTERA_UART_STATUS_PE_MSK 0x0001 /* parity error */
50 #define ALTERA_UART_STATUS_FE_MSK 0x0002 /* framing error */
51 #define ALTERA_UART_STATUS_BRK_MSK 0x0004 /* break */
52 #define ALTERA_UART_STATUS_ROE_MSK 0x0008 /* RX overrun error */
53 #define ALTERA_UART_STATUS_TOE_MSK 0x0010 /* TX overrun error */
54 #define ALTERA_UART_STATUS_TMT_MSK 0x0020 /* TX shift register state */
55 #define ALTERA_UART_STATUS_TRDY_MSK 0x0040 /* TX ready */
56 #define ALTERA_UART_STATUS_RRDY_MSK 0x0080 /* RX ready */
57 #define ALTERA_UART_STATUS_E_MSK 0x0100 /* exception condition */
58 #define ALTERA_UART_STATUS_DCTS_MSK 0x0400 /* CTS logic-level change */
59 #define ALTERA_UART_STATUS_CTS_MSK 0x0800 /* CTS logic state */
60 #define ALTERA_UART_STATUS_EOP_MSK 0x1000 /* EOP written/read */
62 /* Enable interrupt on... */
63 #define ALTERA_UART_CONTROL_PE_MSK 0x0001 /* ...parity error */
64 #define ALTERA_UART_CONTROL_FE_MSK 0x0002 /* ...framing error */
65 #define ALTERA_UART_CONTROL_BRK_MSK 0x0004 /* ...break */
66 #define ALTERA_UART_CONTROL_ROE_MSK 0x0008 /* ...RX overrun */
67 #define ALTERA_UART_CONTROL_TOE_MSK 0x0010 /* ...TX overrun */
68 #define ALTERA_UART_CONTROL_TMT_MSK 0x0020 /* ...TX shift register empty */
69 #define ALTERA_UART_CONTROL_TRDY_MSK 0x0040 /* ...TX ready */
70 #define ALTERA_UART_CONTROL_RRDY_MSK 0x0080 /* ...RX ready */
71 #define ALTERA_UART_CONTROL_E_MSK 0x0100 /* ...exception*/
73 #define ALTERA_UART_CONTROL_TRBK_MSK 0x0200 /* TX break */
74 #define ALTERA_UART_CONTROL_DCTS_MSK 0x0400 /* Interrupt on CTS change */
75 #define ALTERA_UART_CONTROL_RTS_MSK 0x0800 /* RTS signal */
76 #define ALTERA_UART_CONTROL_EOP_MSK 0x1000 /* Interrupt on EOP */
79 * Local per-uart structure.
82 struct uart_port port;
83 struct timer_list tmr;
84 unsigned int sigs; /* Local copy of line sigs */
85 unsigned short imr; /* Local IMR mirror */
88 static u32 altera_uart_readl(struct uart_port *port, int reg)
90 return readl(port->membase + (reg << port->regshift));
93 static void altera_uart_writel(struct uart_port *port, u32 dat, int reg)
95 writel(dat, port->membase + (reg << port->regshift));
98 static unsigned int altera_uart_tx_empty(struct uart_port *port)
100 return (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
101 ALTERA_UART_STATUS_TMT_MSK) ? TIOCSER_TEMT : 0;
104 static unsigned int altera_uart_get_mctrl(struct uart_port *port)
106 struct altera_uart *pp = container_of(port, struct altera_uart, port);
109 sigs = (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
110 ALTERA_UART_STATUS_CTS_MSK) ? TIOCM_CTS : 0;
111 sigs |= (pp->sigs & TIOCM_RTS);
116 static void altera_uart_set_mctrl(struct uart_port *port, unsigned int sigs)
118 struct altera_uart *pp = container_of(port, struct altera_uart, port);
121 if (sigs & TIOCM_RTS)
122 pp->imr |= ALTERA_UART_CONTROL_RTS_MSK;
124 pp->imr &= ~ALTERA_UART_CONTROL_RTS_MSK;
125 altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
128 static void altera_uart_start_tx(struct uart_port *port)
130 struct altera_uart *pp = container_of(port, struct altera_uart, port);
132 pp->imr |= ALTERA_UART_CONTROL_TRDY_MSK;
133 altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
136 static void altera_uart_stop_tx(struct uart_port *port)
138 struct altera_uart *pp = container_of(port, struct altera_uart, port);
140 pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK;
141 altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
144 static void altera_uart_stop_rx(struct uart_port *port)
146 struct altera_uart *pp = container_of(port, struct altera_uart, port);
148 pp->imr &= ~ALTERA_UART_CONTROL_RRDY_MSK;
149 altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
152 static void altera_uart_break_ctl(struct uart_port *port, int break_state)
154 struct altera_uart *pp = container_of(port, struct altera_uart, port);
157 spin_lock_irqsave(&port->lock, flags);
158 if (break_state == -1)
159 pp->imr |= ALTERA_UART_CONTROL_TRBK_MSK;
161 pp->imr &= ~ALTERA_UART_CONTROL_TRBK_MSK;
162 altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
163 spin_unlock_irqrestore(&port->lock, flags);
166 static void altera_uart_set_termios(struct uart_port *port,
167 struct ktermios *termios,
168 struct ktermios *old)
171 unsigned int baud, baudclk;
173 baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
174 baudclk = port->uartclk / baud;
177 tty_termios_copy_hw(termios, old);
178 tty_termios_encode_baud_rate(termios, baud, baud);
180 spin_lock_irqsave(&port->lock, flags);
181 uart_update_timeout(port, termios->c_cflag, baud);
182 altera_uart_writel(port, baudclk, ALTERA_UART_DIVISOR_REG);
183 spin_unlock_irqrestore(&port->lock, flags);
186 * FIXME: port->read_status_mask and port->ignore_status_mask
187 * need to be initialized based on termios settings for
188 * INPCK, IGNBRK, IGNPAR, PARMRK, BRKINT
192 static void altera_uart_rx_chars(struct altera_uart *pp)
194 struct uart_port *port = &pp->port;
195 unsigned char ch, flag;
196 unsigned short status;
198 while ((status = altera_uart_readl(port, ALTERA_UART_STATUS_REG)) &
199 ALTERA_UART_STATUS_RRDY_MSK) {
200 ch = altera_uart_readl(port, ALTERA_UART_RXDATA_REG);
204 if (status & ALTERA_UART_STATUS_E_MSK) {
205 altera_uart_writel(port, status,
206 ALTERA_UART_STATUS_REG);
208 if (status & ALTERA_UART_STATUS_BRK_MSK) {
210 if (uart_handle_break(port))
212 } else if (status & ALTERA_UART_STATUS_PE_MSK) {
213 port->icount.parity++;
214 } else if (status & ALTERA_UART_STATUS_ROE_MSK) {
215 port->icount.overrun++;
216 } else if (status & ALTERA_UART_STATUS_FE_MSK) {
217 port->icount.frame++;
220 status &= port->read_status_mask;
222 if (status & ALTERA_UART_STATUS_BRK_MSK)
224 else if (status & ALTERA_UART_STATUS_PE_MSK)
226 else if (status & ALTERA_UART_STATUS_FE_MSK)
230 if (uart_handle_sysrq_char(port, ch))
232 uart_insert_char(port, status, ALTERA_UART_STATUS_ROE_MSK, ch,
236 spin_unlock(&port->lock);
237 tty_flip_buffer_push(&port->state->port);
238 spin_lock(&port->lock);
241 static void altera_uart_tx_chars(struct altera_uart *pp)
243 struct uart_port *port = &pp->port;
244 struct circ_buf *xmit = &port->state->xmit;
247 /* Send special char - probably flow control */
248 altera_uart_writel(port, port->x_char, ALTERA_UART_TXDATA_REG);
254 while (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
255 ALTERA_UART_STATUS_TRDY_MSK) {
256 if (xmit->head == xmit->tail)
258 altera_uart_writel(port, xmit->buf[xmit->tail],
259 ALTERA_UART_TXDATA_REG);
260 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
264 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
265 uart_write_wakeup(port);
267 if (xmit->head == xmit->tail) {
268 pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK;
269 altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
273 static irqreturn_t altera_uart_interrupt(int irq, void *data)
275 struct uart_port *port = data;
276 struct altera_uart *pp = container_of(port, struct altera_uart, port);
279 isr = altera_uart_readl(port, ALTERA_UART_STATUS_REG) & pp->imr;
281 spin_lock(&port->lock);
282 if (isr & ALTERA_UART_STATUS_RRDY_MSK)
283 altera_uart_rx_chars(pp);
284 if (isr & ALTERA_UART_STATUS_TRDY_MSK)
285 altera_uart_tx_chars(pp);
286 spin_unlock(&port->lock);
288 return IRQ_RETVAL(isr);
291 static void altera_uart_timer(unsigned long data)
293 struct uart_port *port = (void *)data;
294 struct altera_uart *pp = container_of(port, struct altera_uart, port);
296 altera_uart_interrupt(0, port);
297 mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
300 static void altera_uart_config_port(struct uart_port *port, int flags)
302 port->type = PORT_ALTERA_UART;
304 /* Clear mask, so no surprise interrupts. */
305 altera_uart_writel(port, 0, ALTERA_UART_CONTROL_REG);
306 /* Clear status register */
307 altera_uart_writel(port, 0, ALTERA_UART_STATUS_REG);
310 static int altera_uart_startup(struct uart_port *port)
312 struct altera_uart *pp = container_of(port, struct altera_uart, port);
317 setup_timer(&pp->tmr, altera_uart_timer, (unsigned long)port);
318 mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
322 ret = request_irq(port->irq, altera_uart_interrupt, 0,
325 pr_err(DRV_NAME ": unable to attach Altera UART %d "
326 "interrupt vector=%d\n", port->line, port->irq);
330 spin_lock_irqsave(&port->lock, flags);
332 /* Enable RX interrupts now */
333 pp->imr = ALTERA_UART_CONTROL_RRDY_MSK;
334 writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG);
336 spin_unlock_irqrestore(&port->lock, flags);
341 static void altera_uart_shutdown(struct uart_port *port)
343 struct altera_uart *pp = container_of(port, struct altera_uart, port);
346 spin_lock_irqsave(&port->lock, flags);
348 /* Disable all interrupts now */
350 writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG);
352 spin_unlock_irqrestore(&port->lock, flags);
355 free_irq(port->irq, port);
357 del_timer_sync(&pp->tmr);
360 static const char *altera_uart_type(struct uart_port *port)
362 return (port->type == PORT_ALTERA_UART) ? "Altera UART" : NULL;
365 static int altera_uart_request_port(struct uart_port *port)
367 /* UARTs always present */
371 static void altera_uart_release_port(struct uart_port *port)
373 /* Nothing to release... */
376 static int altera_uart_verify_port(struct uart_port *port,
377 struct serial_struct *ser)
379 if ((ser->type != PORT_UNKNOWN) && (ser->type != PORT_ALTERA_UART))
384 #ifdef CONFIG_CONSOLE_POLL
385 static int altera_uart_poll_get_char(struct uart_port *port)
387 while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
388 ALTERA_UART_STATUS_RRDY_MSK))
391 return altera_uart_readl(port, ALTERA_UART_RXDATA_REG);
394 static void altera_uart_poll_put_char(struct uart_port *port, unsigned char c)
396 while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
397 ALTERA_UART_STATUS_TRDY_MSK))
400 altera_uart_writel(port, c, ALTERA_UART_TXDATA_REG);
405 * Define the basic serial functions we support.
407 static struct uart_ops altera_uart_ops = {
408 .tx_empty = altera_uart_tx_empty,
409 .get_mctrl = altera_uart_get_mctrl,
410 .set_mctrl = altera_uart_set_mctrl,
411 .start_tx = altera_uart_start_tx,
412 .stop_tx = altera_uart_stop_tx,
413 .stop_rx = altera_uart_stop_rx,
414 .break_ctl = altera_uart_break_ctl,
415 .startup = altera_uart_startup,
416 .shutdown = altera_uart_shutdown,
417 .set_termios = altera_uart_set_termios,
418 .type = altera_uart_type,
419 .request_port = altera_uart_request_port,
420 .release_port = altera_uart_release_port,
421 .config_port = altera_uart_config_port,
422 .verify_port = altera_uart_verify_port,
423 #ifdef CONFIG_CONSOLE_POLL
424 .poll_get_char = altera_uart_poll_get_char,
425 .poll_put_char = altera_uart_poll_put_char,
429 static struct altera_uart altera_uart_ports[CONFIG_SERIAL_ALTERA_UART_MAXPORTS];
431 #if defined(CONFIG_SERIAL_ALTERA_UART_CONSOLE)
433 static void altera_uart_console_putc(struct uart_port *port, int c)
435 while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
436 ALTERA_UART_STATUS_TRDY_MSK))
439 writel(c, port->membase + ALTERA_UART_TXDATA_REG);
442 static void altera_uart_console_write(struct console *co, const char *s,
445 struct uart_port *port = &(altera_uart_ports + co->index)->port;
447 uart_console_write(port, s, count, altera_uart_console_putc);
450 static int __init altera_uart_console_setup(struct console *co, char *options)
452 struct uart_port *port;
453 int baud = CONFIG_SERIAL_ALTERA_UART_BAUDRATE;
458 if (co->index < 0 || co->index >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS)
460 port = &altera_uart_ports[co->index].port;
465 uart_parse_options(options, &baud, &parity, &bits, &flow);
467 return uart_set_options(port, co, baud, parity, bits, flow);
470 static struct uart_driver altera_uart_driver;
472 static struct console altera_uart_console = {
474 .write = altera_uart_console_write,
475 .device = uart_console_device,
476 .setup = altera_uart_console_setup,
477 .flags = CON_PRINTBUFFER,
479 .data = &altera_uart_driver,
482 static int __init altera_uart_console_init(void)
484 register_console(&altera_uart_console);
488 console_initcall(altera_uart_console_init);
490 #define ALTERA_UART_CONSOLE (&altera_uart_console)
494 #define ALTERA_UART_CONSOLE NULL
496 #endif /* CONFIG_ALTERA_UART_CONSOLE */
499 * Define the altera_uart UART driver structure.
501 static struct uart_driver altera_uart_driver = {
502 .owner = THIS_MODULE,
503 .driver_name = DRV_NAME,
505 .major = SERIAL_ALTERA_MAJOR,
506 .minor = SERIAL_ALTERA_MINOR,
507 .nr = CONFIG_SERIAL_ALTERA_UART_MAXPORTS,
508 .cons = ALTERA_UART_CONSOLE,
512 static int altera_uart_get_of_uartclk(struct platform_device *pdev,
513 struct uart_port *port)
518 clk = of_get_property(pdev->dev.of_node, "clock-frequency", &len);
519 if (!clk || len < sizeof(__be32))
522 port->uartclk = be32_to_cpup(clk);
527 static int altera_uart_get_of_uartclk(struct platform_device *pdev,
528 struct uart_port *port)
532 #endif /* CONFIG_OF */
534 static int altera_uart_probe(struct platform_device *pdev)
536 struct altera_uart_platform_uart *platp = dev_get_platdata(&pdev->dev);
537 struct uart_port *port;
538 struct resource *res_mem;
539 struct resource *res_irq;
543 /* if id is -1 scan for a free id and use that one */
545 for (i = 0; i < CONFIG_SERIAL_ALTERA_UART_MAXPORTS; i++)
546 if (altera_uart_ports[i].port.mapbase == 0)
550 if (i < 0 || i >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS)
553 port = &altera_uart_ports[i].port;
555 res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
557 port->mapbase = res_mem->start;
559 port->mapbase = platp->mapbase;
563 res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
565 port->irq = res_irq->start;
567 port->irq = platp->irq;
569 /* Check platform data first so we can override device node data */
571 port->uartclk = platp->uartclk;
573 ret = altera_uart_get_of_uartclk(pdev, port);
578 port->membase = ioremap(port->mapbase, ALTERA_UART_SIZE);
583 port->regshift = platp->bus_shift;
588 port->type = PORT_ALTERA_UART;
589 port->iotype = SERIAL_IO_MEM;
590 port->ops = &altera_uart_ops;
591 port->flags = UPF_BOOT_AUTOCONF;
592 port->dev = &pdev->dev;
594 platform_set_drvdata(pdev, port);
596 uart_add_one_port(&altera_uart_driver, port);
601 static int altera_uart_remove(struct platform_device *pdev)
603 struct uart_port *port = platform_get_drvdata(pdev);
606 uart_remove_one_port(&altera_uart_driver, port);
614 static const struct of_device_id altera_uart_match[] = {
615 { .compatible = "ALTR,uart-1.0", },
616 { .compatible = "altr,uart-1.0", },
619 MODULE_DEVICE_TABLE(of, altera_uart_match);
620 #endif /* CONFIG_OF */
622 static struct platform_driver altera_uart_platform_driver = {
623 .probe = altera_uart_probe,
624 .remove = altera_uart_remove,
627 .of_match_table = of_match_ptr(altera_uart_match),
631 static int __init altera_uart_init(void)
635 rc = uart_register_driver(&altera_uart_driver);
638 rc = platform_driver_register(&altera_uart_platform_driver);
640 uart_unregister_driver(&altera_uart_driver);
644 static void __exit altera_uart_exit(void)
646 platform_driver_unregister(&altera_uart_platform_driver);
647 uart_unregister_driver(&altera_uart_driver);
650 module_init(altera_uart_init);
651 module_exit(altera_uart_exit);
653 MODULE_DESCRIPTION("Altera UART driver");
654 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
655 MODULE_LICENSE("GPL");
656 MODULE_ALIAS("platform:" DRV_NAME);
657 MODULE_ALIAS_CHARDEV_MAJOR(SERIAL_ALTERA_MAJOR);