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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * altera_uart.c -- Altera UART driver
4 *
5 * Based on mcf.c -- Freescale ColdFire UART driver
6 *
7 * (C) Copyright 2003-2007, Greg Ungerer <gerg@snapgear.com>
8 * (C) Copyright 2008, Thomas Chou <thomas@wytron.com.tw>
9 * (C) Copyright 2010, Tobias Klauser <tklauser@distanz.ch>
10 */
11
12#include <linux/kernel.h>
13#include <linux/init.h>
14#include <linux/timer.h>
15#include <linux/interrupt.h>
16#include <linux/module.h>
17#include <linux/console.h>
18#include <linux/tty.h>
19#include <linux/tty_flip.h>
20#include <linux/serial.h>
21#include <linux/serial_core.h>
22#include <linux/platform_device.h>
23#include <linux/of.h>
24#include <linux/io.h>
25#include <linux/altera_uart.h>
26
27#define DRV_NAME "altera_uart"
28#define SERIAL_ALTERA_MAJOR 204
29#define SERIAL_ALTERA_MINOR 213
30
31/*
32 * Altera UART register definitions according to the Nios UART datasheet:
33 * http://www.altera.com/literature/ds/ds_nios_uart.pdf
34 */
35
36#define ALTERA_UART_SIZE 32
37
38#define ALTERA_UART_RXDATA_REG 0
39#define ALTERA_UART_TXDATA_REG 4
40#define ALTERA_UART_STATUS_REG 8
41#define ALTERA_UART_CONTROL_REG 12
42#define ALTERA_UART_DIVISOR_REG 16
43#define ALTERA_UART_EOP_REG 20
44
45#define ALTERA_UART_STATUS_PE_MSK 0x0001 /* parity error */
46#define ALTERA_UART_STATUS_FE_MSK 0x0002 /* framing error */
47#define ALTERA_UART_STATUS_BRK_MSK 0x0004 /* break */
48#define ALTERA_UART_STATUS_ROE_MSK 0x0008 /* RX overrun error */
49#define ALTERA_UART_STATUS_TOE_MSK 0x0010 /* TX overrun error */
50#define ALTERA_UART_STATUS_TMT_MSK 0x0020 /* TX shift register state */
51#define ALTERA_UART_STATUS_TRDY_MSK 0x0040 /* TX ready */
52#define ALTERA_UART_STATUS_RRDY_MSK 0x0080 /* RX ready */
53#define ALTERA_UART_STATUS_E_MSK 0x0100 /* exception condition */
54#define ALTERA_UART_STATUS_DCTS_MSK 0x0400 /* CTS logic-level change */
55#define ALTERA_UART_STATUS_CTS_MSK 0x0800 /* CTS logic state */
56#define ALTERA_UART_STATUS_EOP_MSK 0x1000 /* EOP written/read */
57
58 /* Enable interrupt on... */
59#define ALTERA_UART_CONTROL_PE_MSK 0x0001 /* ...parity error */
60#define ALTERA_UART_CONTROL_FE_MSK 0x0002 /* ...framing error */
61#define ALTERA_UART_CONTROL_BRK_MSK 0x0004 /* ...break */
62#define ALTERA_UART_CONTROL_ROE_MSK 0x0008 /* ...RX overrun */
63#define ALTERA_UART_CONTROL_TOE_MSK 0x0010 /* ...TX overrun */
64#define ALTERA_UART_CONTROL_TMT_MSK 0x0020 /* ...TX shift register empty */
65#define ALTERA_UART_CONTROL_TRDY_MSK 0x0040 /* ...TX ready */
66#define ALTERA_UART_CONTROL_RRDY_MSK 0x0080 /* ...RX ready */
67#define ALTERA_UART_CONTROL_E_MSK 0x0100 /* ...exception*/
68
69#define ALTERA_UART_CONTROL_TRBK_MSK 0x0200 /* TX break */
70#define ALTERA_UART_CONTROL_DCTS_MSK 0x0400 /* Interrupt on CTS change */
71#define ALTERA_UART_CONTROL_RTS_MSK 0x0800 /* RTS signal */
72#define ALTERA_UART_CONTROL_EOP_MSK 0x1000 /* Interrupt on EOP */
73
74/*
75 * Local per-uart structure.
76 */
77struct altera_uart {
78 struct uart_port port;
79 struct timer_list tmr;
80 unsigned int sigs; /* Local copy of line sigs */
81 unsigned short imr; /* Local IMR mirror */
82};
83
84static u32 altera_uart_readl(struct uart_port *port, int reg)
85{
86 return readl(port->membase + (reg << port->regshift));
87}
88
89static void altera_uart_writel(struct uart_port *port, u32 dat, int reg)
90{
91 writel(dat, port->membase + (reg << port->regshift));
92}
93
94static unsigned int altera_uart_tx_empty(struct uart_port *port)
95{
96 return (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
97 ALTERA_UART_STATUS_TMT_MSK) ? TIOCSER_TEMT : 0;
98}
99
100static unsigned int altera_uart_get_mctrl(struct uart_port *port)
101{
102 struct altera_uart *pp = container_of(port, struct altera_uart, port);
103 unsigned int sigs;
104
105 sigs = (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
106 ALTERA_UART_STATUS_CTS_MSK) ? TIOCM_CTS : 0;
107 sigs |= (pp->sigs & TIOCM_RTS);
108
109 return sigs;
110}
111
112static void altera_uart_update_ctrl_reg(struct altera_uart *pp)
113{
114 unsigned short imr = pp->imr;
115
116 /*
117 * If the device doesn't have an irq, ensure that the irq bits are
118 * masked out to keep the irq line inactive.
119 */
120 if (!pp->port.irq)
121 imr &= ALTERA_UART_CONTROL_TRBK_MSK | ALTERA_UART_CONTROL_RTS_MSK;
122
123 altera_uart_writel(&pp->port, imr, ALTERA_UART_CONTROL_REG);
124}
125
126static void altera_uart_set_mctrl(struct uart_port *port, unsigned int sigs)
127{
128 struct altera_uart *pp = container_of(port, struct altera_uart, port);
129
130 pp->sigs = sigs;
131 if (sigs & TIOCM_RTS)
132 pp->imr |= ALTERA_UART_CONTROL_RTS_MSK;
133 else
134 pp->imr &= ~ALTERA_UART_CONTROL_RTS_MSK;
135 altera_uart_update_ctrl_reg(pp);
136}
137
138static void altera_uart_start_tx(struct uart_port *port)
139{
140 struct altera_uart *pp = container_of(port, struct altera_uart, port);
141
142 pp->imr |= ALTERA_UART_CONTROL_TRDY_MSK;
143 altera_uart_update_ctrl_reg(pp);
144}
145
146static void altera_uart_stop_tx(struct uart_port *port)
147{
148 struct altera_uart *pp = container_of(port, struct altera_uart, port);
149
150 pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK;
151 altera_uart_update_ctrl_reg(pp);
152}
153
154static void altera_uart_stop_rx(struct uart_port *port)
155{
156 struct altera_uart *pp = container_of(port, struct altera_uart, port);
157
158 pp->imr &= ~ALTERA_UART_CONTROL_RRDY_MSK;
159 altera_uart_update_ctrl_reg(pp);
160}
161
162static void altera_uart_break_ctl(struct uart_port *port, int break_state)
163{
164 struct altera_uart *pp = container_of(port, struct altera_uart, port);
165 unsigned long flags;
166
167 spin_lock_irqsave(&port->lock, flags);
168 if (break_state == -1)
169 pp->imr |= ALTERA_UART_CONTROL_TRBK_MSK;
170 else
171 pp->imr &= ~ALTERA_UART_CONTROL_TRBK_MSK;
172 altera_uart_update_ctrl_reg(pp);
173 spin_unlock_irqrestore(&port->lock, flags);
174}
175
176static void altera_uart_set_termios(struct uart_port *port,
177 struct ktermios *termios,
178 struct ktermios *old)
179{
180 unsigned long flags;
181 unsigned int baud, baudclk;
182
183 baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
184 baudclk = port->uartclk / baud;
185
186 if (old)
187 tty_termios_copy_hw(termios, old);
188 tty_termios_encode_baud_rate(termios, baud, baud);
189
190 spin_lock_irqsave(&port->lock, flags);
191 uart_update_timeout(port, termios->c_cflag, baud);
192 altera_uart_writel(port, baudclk, ALTERA_UART_DIVISOR_REG);
193 spin_unlock_irqrestore(&port->lock, flags);
194
195 /*
196 * FIXME: port->read_status_mask and port->ignore_status_mask
197 * need to be initialized based on termios settings for
198 * INPCK, IGNBRK, IGNPAR, PARMRK, BRKINT
199 */
200}
201
202static void altera_uart_rx_chars(struct altera_uart *pp)
203{
204 struct uart_port *port = &pp->port;
205 unsigned char ch, flag;
206 unsigned short status;
207
208 while ((status = altera_uart_readl(port, ALTERA_UART_STATUS_REG)) &
209 ALTERA_UART_STATUS_RRDY_MSK) {
210 ch = altera_uart_readl(port, ALTERA_UART_RXDATA_REG);
211 flag = TTY_NORMAL;
212 port->icount.rx++;
213
214 if (status & ALTERA_UART_STATUS_E_MSK) {
215 altera_uart_writel(port, status,
216 ALTERA_UART_STATUS_REG);
217
218 if (status & ALTERA_UART_STATUS_BRK_MSK) {
219 port->icount.brk++;
220 if (uart_handle_break(port))
221 continue;
222 } else if (status & ALTERA_UART_STATUS_PE_MSK) {
223 port->icount.parity++;
224 } else if (status & ALTERA_UART_STATUS_ROE_MSK) {
225 port->icount.overrun++;
226 } else if (status & ALTERA_UART_STATUS_FE_MSK) {
227 port->icount.frame++;
228 }
229
230 status &= port->read_status_mask;
231
232 if (status & ALTERA_UART_STATUS_BRK_MSK)
233 flag = TTY_BREAK;
234 else if (status & ALTERA_UART_STATUS_PE_MSK)
235 flag = TTY_PARITY;
236 else if (status & ALTERA_UART_STATUS_FE_MSK)
237 flag = TTY_FRAME;
238 }
239
240 if (uart_handle_sysrq_char(port, ch))
241 continue;
242 uart_insert_char(port, status, ALTERA_UART_STATUS_ROE_MSK, ch,
243 flag);
244 }
245
246 spin_unlock(&port->lock);
247 tty_flip_buffer_push(&port->state->port);
248 spin_lock(&port->lock);
249}
250
251static void altera_uart_tx_chars(struct altera_uart *pp)
252{
253 struct uart_port *port = &pp->port;
254 struct circ_buf *xmit = &port->state->xmit;
255
256 if (port->x_char) {
257 /* Send special char - probably flow control */
258 altera_uart_writel(port, port->x_char, ALTERA_UART_TXDATA_REG);
259 port->x_char = 0;
260 port->icount.tx++;
261 return;
262 }
263
264 while (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
265 ALTERA_UART_STATUS_TRDY_MSK) {
266 if (xmit->head == xmit->tail)
267 break;
268 altera_uart_writel(port, xmit->buf[xmit->tail],
269 ALTERA_UART_TXDATA_REG);
270 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
271 port->icount.tx++;
272 }
273
274 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
275 uart_write_wakeup(port);
276
277 if (xmit->head == xmit->tail) {
278 pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK;
279 altera_uart_update_ctrl_reg(pp);
280 }
281}
282
283static irqreturn_t altera_uart_interrupt(int irq, void *data)
284{
285 struct uart_port *port = data;
286 struct altera_uart *pp = container_of(port, struct altera_uart, port);
287 unsigned int isr;
288
289 isr = altera_uart_readl(port, ALTERA_UART_STATUS_REG) & pp->imr;
290
291 spin_lock(&port->lock);
292 if (isr & ALTERA_UART_STATUS_RRDY_MSK)
293 altera_uart_rx_chars(pp);
294 if (isr & ALTERA_UART_STATUS_TRDY_MSK)
295 altera_uart_tx_chars(pp);
296 spin_unlock(&port->lock);
297
298 return IRQ_RETVAL(isr);
299}
300
301static void altera_uart_timer(struct timer_list *t)
302{
303 struct altera_uart *pp = from_timer(pp, t, tmr);
304 struct uart_port *port = &pp->port;
305
306 altera_uart_interrupt(0, port);
307 mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
308}
309
310static void altera_uart_config_port(struct uart_port *port, int flags)
311{
312 port->type = PORT_ALTERA_UART;
313
314 /* Clear mask, so no surprise interrupts. */
315 altera_uart_writel(port, 0, ALTERA_UART_CONTROL_REG);
316 /* Clear status register */
317 altera_uart_writel(port, 0, ALTERA_UART_STATUS_REG);
318}
319
320static int altera_uart_startup(struct uart_port *port)
321{
322 struct altera_uart *pp = container_of(port, struct altera_uart, port);
323 unsigned long flags;
324
325 if (!port->irq) {
326 timer_setup(&pp->tmr, altera_uart_timer, 0);
327 mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
328 } else {
329 int ret;
330
331 ret = request_irq(port->irq, altera_uart_interrupt, 0,
332 DRV_NAME, port);
333 if (ret) {
334 pr_err(DRV_NAME ": unable to attach Altera UART %d "
335 "interrupt vector=%d\n", port->line, port->irq);
336 return ret;
337 }
338 }
339
340 spin_lock_irqsave(&port->lock, flags);
341
342 /* Enable RX interrupts now */
343 pp->imr = ALTERA_UART_CONTROL_RRDY_MSK;
344 altera_uart_update_ctrl_reg(pp);
345
346 spin_unlock_irqrestore(&port->lock, flags);
347
348 return 0;
349}
350
351static void altera_uart_shutdown(struct uart_port *port)
352{
353 struct altera_uart *pp = container_of(port, struct altera_uart, port);
354 unsigned long flags;
355
356 spin_lock_irqsave(&port->lock, flags);
357
358 /* Disable all interrupts now */
359 pp->imr = 0;
360 altera_uart_update_ctrl_reg(pp);
361
362 spin_unlock_irqrestore(&port->lock, flags);
363
364 if (port->irq)
365 free_irq(port->irq, port);
366 else
367 del_timer_sync(&pp->tmr);
368}
369
370static const char *altera_uart_type(struct uart_port *port)
371{
372 return (port->type == PORT_ALTERA_UART) ? "Altera UART" : NULL;
373}
374
375static int altera_uart_request_port(struct uart_port *port)
376{
377 /* UARTs always present */
378 return 0;
379}
380
381static void altera_uart_release_port(struct uart_port *port)
382{
383 /* Nothing to release... */
384}
385
386static int altera_uart_verify_port(struct uart_port *port,
387 struct serial_struct *ser)
388{
389 if ((ser->type != PORT_UNKNOWN) && (ser->type != PORT_ALTERA_UART))
390 return -EINVAL;
391 return 0;
392}
393
394#ifdef CONFIG_CONSOLE_POLL
395static int altera_uart_poll_get_char(struct uart_port *port)
396{
397 while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
398 ALTERA_UART_STATUS_RRDY_MSK))
399 cpu_relax();
400
401 return altera_uart_readl(port, ALTERA_UART_RXDATA_REG);
402}
403
404static void altera_uart_poll_put_char(struct uart_port *port, unsigned char c)
405{
406 while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
407 ALTERA_UART_STATUS_TRDY_MSK))
408 cpu_relax();
409
410 altera_uart_writel(port, c, ALTERA_UART_TXDATA_REG);
411}
412#endif
413
414/*
415 * Define the basic serial functions we support.
416 */
417static const struct uart_ops altera_uart_ops = {
418 .tx_empty = altera_uart_tx_empty,
419 .get_mctrl = altera_uart_get_mctrl,
420 .set_mctrl = altera_uart_set_mctrl,
421 .start_tx = altera_uart_start_tx,
422 .stop_tx = altera_uart_stop_tx,
423 .stop_rx = altera_uart_stop_rx,
424 .break_ctl = altera_uart_break_ctl,
425 .startup = altera_uart_startup,
426 .shutdown = altera_uart_shutdown,
427 .set_termios = altera_uart_set_termios,
428 .type = altera_uart_type,
429 .request_port = altera_uart_request_port,
430 .release_port = altera_uart_release_port,
431 .config_port = altera_uart_config_port,
432 .verify_port = altera_uart_verify_port,
433#ifdef CONFIG_CONSOLE_POLL
434 .poll_get_char = altera_uart_poll_get_char,
435 .poll_put_char = altera_uart_poll_put_char,
436#endif
437};
438
439static struct altera_uart altera_uart_ports[CONFIG_SERIAL_ALTERA_UART_MAXPORTS];
440
441#if defined(CONFIG_SERIAL_ALTERA_UART_CONSOLE)
442
443static void altera_uart_console_putc(struct uart_port *port, int c)
444{
445 while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
446 ALTERA_UART_STATUS_TRDY_MSK))
447 cpu_relax();
448
449 altera_uart_writel(port, c, ALTERA_UART_TXDATA_REG);
450}
451
452static void altera_uart_console_write(struct console *co, const char *s,
453 unsigned int count)
454{
455 struct uart_port *port = &(altera_uart_ports + co->index)->port;
456
457 uart_console_write(port, s, count, altera_uart_console_putc);
458}
459
460static int __init altera_uart_console_setup(struct console *co, char *options)
461{
462 struct uart_port *port;
463 int baud = CONFIG_SERIAL_ALTERA_UART_BAUDRATE;
464 int bits = 8;
465 int parity = 'n';
466 int flow = 'n';
467
468 if (co->index < 0 || co->index >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS)
469 return -EINVAL;
470 port = &altera_uart_ports[co->index].port;
471 if (!port->membase)
472 return -ENODEV;
473
474 if (options)
475 uart_parse_options(options, &baud, &parity, &bits, &flow);
476
477 return uart_set_options(port, co, baud, parity, bits, flow);
478}
479
480static struct uart_driver altera_uart_driver;
481
482static struct console altera_uart_console = {
483 .name = "ttyAL",
484 .write = altera_uart_console_write,
485 .device = uart_console_device,
486 .setup = altera_uart_console_setup,
487 .flags = CON_PRINTBUFFER,
488 .index = -1,
489 .data = &altera_uart_driver,
490};
491
492static int __init altera_uart_console_init(void)
493{
494 register_console(&altera_uart_console);
495 return 0;
496}
497
498console_initcall(altera_uart_console_init);
499
500#define ALTERA_UART_CONSOLE (&altera_uart_console)
501
502static void altera_uart_earlycon_write(struct console *co, const char *s,
503 unsigned int count)
504{
505 struct earlycon_device *dev = co->data;
506
507 uart_console_write(&dev->port, s, count, altera_uart_console_putc);
508}
509
510static int __init altera_uart_earlycon_setup(struct earlycon_device *dev,
511 const char *options)
512{
513 struct uart_port *port = &dev->port;
514
515 if (!port->membase)
516 return -ENODEV;
517
518 /* Enable RX interrupts now */
519 altera_uart_writel(port, ALTERA_UART_CONTROL_RRDY_MSK,
520 ALTERA_UART_CONTROL_REG);
521
522 if (dev->baud) {
523 unsigned int baudclk = port->uartclk / dev->baud;
524
525 altera_uart_writel(port, baudclk, ALTERA_UART_DIVISOR_REG);
526 }
527
528 dev->con->write = altera_uart_earlycon_write;
529 return 0;
530}
531
532OF_EARLYCON_DECLARE(uart, "altr,uart-1.0", altera_uart_earlycon_setup);
533
534#else
535
536#define ALTERA_UART_CONSOLE NULL
537
538#endif /* CONFIG_SERIAL_ALTERA_UART_CONSOLE */
539
540/*
541 * Define the altera_uart UART driver structure.
542 */
543static struct uart_driver altera_uart_driver = {
544 .owner = THIS_MODULE,
545 .driver_name = DRV_NAME,
546 .dev_name = "ttyAL",
547 .major = SERIAL_ALTERA_MAJOR,
548 .minor = SERIAL_ALTERA_MINOR,
549 .nr = CONFIG_SERIAL_ALTERA_UART_MAXPORTS,
550 .cons = ALTERA_UART_CONSOLE,
551};
552
553static int altera_uart_probe(struct platform_device *pdev)
554{
555 struct altera_uart_platform_uart *platp = dev_get_platdata(&pdev->dev);
556 struct uart_port *port;
557 struct resource *res_mem;
558 struct resource *res_irq;
559 int i = pdev->id;
560 int ret;
561
562 /* if id is -1 scan for a free id and use that one */
563 if (i == -1) {
564 for (i = 0; i < CONFIG_SERIAL_ALTERA_UART_MAXPORTS; i++)
565 if (altera_uart_ports[i].port.mapbase == 0)
566 break;
567 }
568
569 if (i < 0 || i >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS)
570 return -EINVAL;
571
572 port = &altera_uart_ports[i].port;
573
574 res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
575 if (res_mem)
576 port->mapbase = res_mem->start;
577 else if (platp)
578 port->mapbase = platp->mapbase;
579 else
580 return -EINVAL;
581
582 res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
583 if (res_irq)
584 port->irq = res_irq->start;
585 else if (platp)
586 port->irq = platp->irq;
587
588 /* Check platform data first so we can override device node data */
589 if (platp)
590 port->uartclk = platp->uartclk;
591 else {
592 ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency",
593 &port->uartclk);
594 if (ret)
595 return ret;
596 }
597
598 port->membase = ioremap(port->mapbase, ALTERA_UART_SIZE);
599 if (!port->membase)
600 return -ENOMEM;
601
602 if (platp)
603 port->regshift = platp->bus_shift;
604 else
605 port->regshift = 0;
606
607 port->line = i;
608 port->type = PORT_ALTERA_UART;
609 port->iotype = SERIAL_IO_MEM;
610 port->ops = &altera_uart_ops;
611 port->flags = UPF_BOOT_AUTOCONF;
612 port->dev = &pdev->dev;
613
614 platform_set_drvdata(pdev, port);
615
616 uart_add_one_port(&altera_uart_driver, port);
617
618 return 0;
619}
620
621static int altera_uart_remove(struct platform_device *pdev)
622{
623 struct uart_port *port = platform_get_drvdata(pdev);
624
625 if (port) {
626 uart_remove_one_port(&altera_uart_driver, port);
627 port->mapbase = 0;
628 iounmap(port->membase);
629 }
630
631 return 0;
632}
633
634#ifdef CONFIG_OF
635static const struct of_device_id altera_uart_match[] = {
636 { .compatible = "ALTR,uart-1.0", },
637 { .compatible = "altr,uart-1.0", },
638 {},
639};
640MODULE_DEVICE_TABLE(of, altera_uart_match);
641#endif /* CONFIG_OF */
642
643static struct platform_driver altera_uart_platform_driver = {
644 .probe = altera_uart_probe,
645 .remove = altera_uart_remove,
646 .driver = {
647 .name = DRV_NAME,
648 .of_match_table = of_match_ptr(altera_uart_match),
649 },
650};
651
652static int __init altera_uart_init(void)
653{
654 int rc;
655
656 rc = uart_register_driver(&altera_uart_driver);
657 if (rc)
658 return rc;
659 rc = platform_driver_register(&altera_uart_platform_driver);
660 if (rc)
661 uart_unregister_driver(&altera_uart_driver);
662 return rc;
663}
664
665static void __exit altera_uart_exit(void)
666{
667 platform_driver_unregister(&altera_uart_platform_driver);
668 uart_unregister_driver(&altera_uart_driver);
669}
670
671module_init(altera_uart_init);
672module_exit(altera_uart_exit);
673
674MODULE_DESCRIPTION("Altera UART driver");
675MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
676MODULE_LICENSE("GPL");
677MODULE_ALIAS("platform:" DRV_NAME);
678MODULE_ALIAS_CHARDEV_MAJOR(SERIAL_ALTERA_MAJOR);
1/*
2 * altera_uart.c -- Altera UART driver
3 *
4 * Based on mcf.c -- Freescale ColdFire UART driver
5 *
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>
9 *
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.
14 */
15
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>
27#include <linux/of.h>
28#include <linux/io.h>
29#include <linux/altera_uart.h>
30
31#define DRV_NAME "altera_uart"
32#define SERIAL_ALTERA_MAJOR 204
33#define SERIAL_ALTERA_MINOR 213
34
35/*
36 * Altera UART register definitions according to the Nios UART datasheet:
37 * http://www.altera.com/literature/ds/ds_nios_uart.pdf
38 */
39
40#define ALTERA_UART_SIZE 32
41
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
48
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 */
61
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*/
72
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 */
77
78/*
79 * Local per-uart structure.
80 */
81struct altera_uart {
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 */
86};
87
88static u32 altera_uart_readl(struct uart_port *port, int reg)
89{
90 return readl(port->membase + (reg << port->regshift));
91}
92
93static void altera_uart_writel(struct uart_port *port, u32 dat, int reg)
94{
95 writel(dat, port->membase + (reg << port->regshift));
96}
97
98static unsigned int altera_uart_tx_empty(struct uart_port *port)
99{
100 return (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
101 ALTERA_UART_STATUS_TMT_MSK) ? TIOCSER_TEMT : 0;
102}
103
104static unsigned int altera_uart_get_mctrl(struct uart_port *port)
105{
106 struct altera_uart *pp = container_of(port, struct altera_uart, port);
107 unsigned int sigs;
108
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);
112
113 return sigs;
114}
115
116static void altera_uart_set_mctrl(struct uart_port *port, unsigned int sigs)
117{
118 struct altera_uart *pp = container_of(port, struct altera_uart, port);
119
120 pp->sigs = sigs;
121 if (sigs & TIOCM_RTS)
122 pp->imr |= ALTERA_UART_CONTROL_RTS_MSK;
123 else
124 pp->imr &= ~ALTERA_UART_CONTROL_RTS_MSK;
125 altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
126}
127
128static void altera_uart_start_tx(struct uart_port *port)
129{
130 struct altera_uart *pp = container_of(port, struct altera_uart, port);
131
132 pp->imr |= ALTERA_UART_CONTROL_TRDY_MSK;
133 altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
134}
135
136static void altera_uart_stop_tx(struct uart_port *port)
137{
138 struct altera_uart *pp = container_of(port, struct altera_uart, port);
139
140 pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK;
141 altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
142}
143
144static void altera_uart_stop_rx(struct uart_port *port)
145{
146 struct altera_uart *pp = container_of(port, struct altera_uart, port);
147
148 pp->imr &= ~ALTERA_UART_CONTROL_RRDY_MSK;
149 altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
150}
151
152static void altera_uart_break_ctl(struct uart_port *port, int break_state)
153{
154 struct altera_uart *pp = container_of(port, struct altera_uart, port);
155 unsigned long flags;
156
157 spin_lock_irqsave(&port->lock, flags);
158 if (break_state == -1)
159 pp->imr |= ALTERA_UART_CONTROL_TRBK_MSK;
160 else
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);
164}
165
166static void altera_uart_set_termios(struct uart_port *port,
167 struct ktermios *termios,
168 struct ktermios *old)
169{
170 unsigned long flags;
171 unsigned int baud, baudclk;
172
173 baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
174 baudclk = port->uartclk / baud;
175
176 if (old)
177 tty_termios_copy_hw(termios, old);
178 tty_termios_encode_baud_rate(termios, baud, baud);
179
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);
184
185 /*
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
189 */
190}
191
192static void altera_uart_rx_chars(struct altera_uart *pp)
193{
194 struct uart_port *port = &pp->port;
195 unsigned char ch, flag;
196 unsigned short status;
197
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);
201 flag = TTY_NORMAL;
202 port->icount.rx++;
203
204 if (status & ALTERA_UART_STATUS_E_MSK) {
205 altera_uart_writel(port, status,
206 ALTERA_UART_STATUS_REG);
207
208 if (status & ALTERA_UART_STATUS_BRK_MSK) {
209 port->icount.brk++;
210 if (uart_handle_break(port))
211 continue;
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++;
218 }
219
220 status &= port->read_status_mask;
221
222 if (status & ALTERA_UART_STATUS_BRK_MSK)
223 flag = TTY_BREAK;
224 else if (status & ALTERA_UART_STATUS_PE_MSK)
225 flag = TTY_PARITY;
226 else if (status & ALTERA_UART_STATUS_FE_MSK)
227 flag = TTY_FRAME;
228 }
229
230 if (uart_handle_sysrq_char(port, ch))
231 continue;
232 uart_insert_char(port, status, ALTERA_UART_STATUS_ROE_MSK, ch,
233 flag);
234 }
235
236 spin_unlock(&port->lock);
237 tty_flip_buffer_push(&port->state->port);
238 spin_lock(&port->lock);
239}
240
241static void altera_uart_tx_chars(struct altera_uart *pp)
242{
243 struct uart_port *port = &pp->port;
244 struct circ_buf *xmit = &port->state->xmit;
245
246 if (port->x_char) {
247 /* Send special char - probably flow control */
248 altera_uart_writel(port, port->x_char, ALTERA_UART_TXDATA_REG);
249 port->x_char = 0;
250 port->icount.tx++;
251 return;
252 }
253
254 while (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
255 ALTERA_UART_STATUS_TRDY_MSK) {
256 if (xmit->head == xmit->tail)
257 break;
258 altera_uart_writel(port, xmit->buf[xmit->tail],
259 ALTERA_UART_TXDATA_REG);
260 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
261 port->icount.tx++;
262 }
263
264 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
265 uart_write_wakeup(port);
266
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);
270 }
271}
272
273static irqreturn_t altera_uart_interrupt(int irq, void *data)
274{
275 struct uart_port *port = data;
276 struct altera_uart *pp = container_of(port, struct altera_uart, port);
277 unsigned int isr;
278
279 isr = altera_uart_readl(port, ALTERA_UART_STATUS_REG) & pp->imr;
280
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);
287
288 return IRQ_RETVAL(isr);
289}
290
291static void altera_uart_timer(unsigned long data)
292{
293 struct uart_port *port = (void *)data;
294 struct altera_uart *pp = container_of(port, struct altera_uart, port);
295
296 altera_uart_interrupt(0, port);
297 mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
298}
299
300static void altera_uart_config_port(struct uart_port *port, int flags)
301{
302 port->type = PORT_ALTERA_UART;
303
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);
308}
309
310static int altera_uart_startup(struct uart_port *port)
311{
312 struct altera_uart *pp = container_of(port, struct altera_uart, port);
313 unsigned long flags;
314 int ret;
315
316 if (!port->irq) {
317 setup_timer(&pp->tmr, altera_uart_timer, (unsigned long)port);
318 mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
319 return 0;
320 }
321
322 ret = request_irq(port->irq, altera_uart_interrupt, 0,
323 DRV_NAME, port);
324 if (ret) {
325 pr_err(DRV_NAME ": unable to attach Altera UART %d "
326 "interrupt vector=%d\n", port->line, port->irq);
327 return ret;
328 }
329
330 spin_lock_irqsave(&port->lock, flags);
331
332 /* Enable RX interrupts now */
333 pp->imr = ALTERA_UART_CONTROL_RRDY_MSK;
334 writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG);
335
336 spin_unlock_irqrestore(&port->lock, flags);
337
338 return 0;
339}
340
341static void altera_uart_shutdown(struct uart_port *port)
342{
343 struct altera_uart *pp = container_of(port, struct altera_uart, port);
344 unsigned long flags;
345
346 spin_lock_irqsave(&port->lock, flags);
347
348 /* Disable all interrupts now */
349 pp->imr = 0;
350 writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG);
351
352 spin_unlock_irqrestore(&port->lock, flags);
353
354 if (port->irq)
355 free_irq(port->irq, port);
356 else
357 del_timer_sync(&pp->tmr);
358}
359
360static const char *altera_uart_type(struct uart_port *port)
361{
362 return (port->type == PORT_ALTERA_UART) ? "Altera UART" : NULL;
363}
364
365static int altera_uart_request_port(struct uart_port *port)
366{
367 /* UARTs always present */
368 return 0;
369}
370
371static void altera_uart_release_port(struct uart_port *port)
372{
373 /* Nothing to release... */
374}
375
376static int altera_uart_verify_port(struct uart_port *port,
377 struct serial_struct *ser)
378{
379 if ((ser->type != PORT_UNKNOWN) && (ser->type != PORT_ALTERA_UART))
380 return -EINVAL;
381 return 0;
382}
383
384#ifdef CONFIG_CONSOLE_POLL
385static int altera_uart_poll_get_char(struct uart_port *port)
386{
387 while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
388 ALTERA_UART_STATUS_RRDY_MSK))
389 cpu_relax();
390
391 return altera_uart_readl(port, ALTERA_UART_RXDATA_REG);
392}
393
394static void altera_uart_poll_put_char(struct uart_port *port, unsigned char c)
395{
396 while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
397 ALTERA_UART_STATUS_TRDY_MSK))
398 cpu_relax();
399
400 altera_uart_writel(port, c, ALTERA_UART_TXDATA_REG);
401}
402#endif
403
404/*
405 * Define the basic serial functions we support.
406 */
407static 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,
426#endif
427};
428
429static struct altera_uart altera_uart_ports[CONFIG_SERIAL_ALTERA_UART_MAXPORTS];
430
431#if defined(CONFIG_SERIAL_ALTERA_UART_CONSOLE)
432
433static void altera_uart_console_putc(struct uart_port *port, int c)
434{
435 while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
436 ALTERA_UART_STATUS_TRDY_MSK))
437 cpu_relax();
438
439 writel(c, port->membase + ALTERA_UART_TXDATA_REG);
440}
441
442static void altera_uart_console_write(struct console *co, const char *s,
443 unsigned int count)
444{
445 struct uart_port *port = &(altera_uart_ports + co->index)->port;
446
447 uart_console_write(port, s, count, altera_uart_console_putc);
448}
449
450static int __init altera_uart_console_setup(struct console *co, char *options)
451{
452 struct uart_port *port;
453 int baud = CONFIG_SERIAL_ALTERA_UART_BAUDRATE;
454 int bits = 8;
455 int parity = 'n';
456 int flow = 'n';
457
458 if (co->index < 0 || co->index >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS)
459 return -EINVAL;
460 port = &altera_uart_ports[co->index].port;
461 if (!port->membase)
462 return -ENODEV;
463
464 if (options)
465 uart_parse_options(options, &baud, &parity, &bits, &flow);
466
467 return uart_set_options(port, co, baud, parity, bits, flow);
468}
469
470static struct uart_driver altera_uart_driver;
471
472static struct console altera_uart_console = {
473 .name = "ttyAL",
474 .write = altera_uart_console_write,
475 .device = uart_console_device,
476 .setup = altera_uart_console_setup,
477 .flags = CON_PRINTBUFFER,
478 .index = -1,
479 .data = &altera_uart_driver,
480};
481
482static int __init altera_uart_console_init(void)
483{
484 register_console(&altera_uart_console);
485 return 0;
486}
487
488console_initcall(altera_uart_console_init);
489
490#define ALTERA_UART_CONSOLE (&altera_uart_console)
491
492#else
493
494#define ALTERA_UART_CONSOLE NULL
495
496#endif /* CONFIG_SERIAL_ALTERA_UART_CONSOLE */
497
498/*
499 * Define the altera_uart UART driver structure.
500 */
501static struct uart_driver altera_uart_driver = {
502 .owner = THIS_MODULE,
503 .driver_name = DRV_NAME,
504 .dev_name = "ttyAL",
505 .major = SERIAL_ALTERA_MAJOR,
506 .minor = SERIAL_ALTERA_MINOR,
507 .nr = CONFIG_SERIAL_ALTERA_UART_MAXPORTS,
508 .cons = ALTERA_UART_CONSOLE,
509};
510
511static int altera_uart_probe(struct platform_device *pdev)
512{
513 struct altera_uart_platform_uart *platp = dev_get_platdata(&pdev->dev);
514 struct uart_port *port;
515 struct resource *res_mem;
516 struct resource *res_irq;
517 int i = pdev->id;
518 int ret;
519
520 /* if id is -1 scan for a free id and use that one */
521 if (i == -1) {
522 for (i = 0; i < CONFIG_SERIAL_ALTERA_UART_MAXPORTS; i++)
523 if (altera_uart_ports[i].port.mapbase == 0)
524 break;
525 }
526
527 if (i < 0 || i >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS)
528 return -EINVAL;
529
530 port = &altera_uart_ports[i].port;
531
532 res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
533 if (res_mem)
534 port->mapbase = res_mem->start;
535 else if (platp)
536 port->mapbase = platp->mapbase;
537 else
538 return -EINVAL;
539
540 res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
541 if (res_irq)
542 port->irq = res_irq->start;
543 else if (platp)
544 port->irq = platp->irq;
545
546 /* Check platform data first so we can override device node data */
547 if (platp)
548 port->uartclk = platp->uartclk;
549 else {
550 ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency",
551 &port->uartclk);
552 if (ret)
553 return ret;
554 }
555
556 port->membase = ioremap(port->mapbase, ALTERA_UART_SIZE);
557 if (!port->membase)
558 return -ENOMEM;
559
560 if (platp)
561 port->regshift = platp->bus_shift;
562 else
563 port->regshift = 0;
564
565 port->line = i;
566 port->type = PORT_ALTERA_UART;
567 port->iotype = SERIAL_IO_MEM;
568 port->ops = &altera_uart_ops;
569 port->flags = UPF_BOOT_AUTOCONF;
570 port->dev = &pdev->dev;
571
572 platform_set_drvdata(pdev, port);
573
574 uart_add_one_port(&altera_uart_driver, port);
575
576 return 0;
577}
578
579static int altera_uart_remove(struct platform_device *pdev)
580{
581 struct uart_port *port = platform_get_drvdata(pdev);
582
583 if (port) {
584 uart_remove_one_port(&altera_uart_driver, port);
585 port->mapbase = 0;
586 }
587
588 return 0;
589}
590
591#ifdef CONFIG_OF
592static const struct of_device_id altera_uart_match[] = {
593 { .compatible = "ALTR,uart-1.0", },
594 { .compatible = "altr,uart-1.0", },
595 {},
596};
597MODULE_DEVICE_TABLE(of, altera_uart_match);
598#endif /* CONFIG_OF */
599
600static struct platform_driver altera_uart_platform_driver = {
601 .probe = altera_uart_probe,
602 .remove = altera_uart_remove,
603 .driver = {
604 .name = DRV_NAME,
605 .of_match_table = of_match_ptr(altera_uart_match),
606 },
607};
608
609static int __init altera_uart_init(void)
610{
611 int rc;
612
613 rc = uart_register_driver(&altera_uart_driver);
614 if (rc)
615 return rc;
616 rc = platform_driver_register(&altera_uart_platform_driver);
617 if (rc)
618 uart_unregister_driver(&altera_uart_driver);
619 return rc;
620}
621
622static void __exit altera_uart_exit(void)
623{
624 platform_driver_unregister(&altera_uart_platform_driver);
625 uart_unregister_driver(&altera_uart_driver);
626}
627
628module_init(altera_uart_init);
629module_exit(altera_uart_exit);
630
631MODULE_DESCRIPTION("Altera UART driver");
632MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
633MODULE_LICENSE("GPL");
634MODULE_ALIAS("platform:" DRV_NAME);
635MODULE_ALIAS_CHARDEV_MAJOR(SERIAL_ALTERA_MAJOR);