Merge tag 'v3.3.7' into 3.3/master
[zen-stable.git] / drivers / tty / serial / timbuart.c
blob70f97491d8f28a2771bac4c563b8e781014d522d
1 /*
2 * timbuart.c timberdale FPGA UART driver
3 * Copyright (c) 2009 Intel Corporation
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 /* Supports:
20 * Timberdale FPGA UART
23 #include <linux/pci.h>
24 #include <linux/interrupt.h>
25 #include <linux/serial_core.h>
26 #include <linux/tty.h>
27 #include <linux/tty_flip.h>
28 #include <linux/kernel.h>
29 #include <linux/platform_device.h>
30 #include <linux/ioport.h>
31 #include <linux/slab.h>
32 #include <linux/module.h>
34 #include "timbuart.h"
36 struct timbuart_port {
37 struct uart_port port;
38 struct tasklet_struct tasklet;
39 int usedma;
40 u32 last_ier;
41 struct platform_device *dev;
44 static int baudrates[] = {9600, 19200, 38400, 57600, 115200, 230400, 460800,
45 921600, 1843200, 3250000};
47 static void timbuart_mctrl_check(struct uart_port *port, u32 isr, u32 *ier);
49 static irqreturn_t timbuart_handleinterrupt(int irq, void *devid);
51 static void timbuart_stop_rx(struct uart_port *port)
53 /* spin lock held by upper layer, disable all RX interrupts */
54 u32 ier = ioread32(port->membase + TIMBUART_IER) & ~RXFLAGS;
55 iowrite32(ier, port->membase + TIMBUART_IER);
58 static void timbuart_stop_tx(struct uart_port *port)
60 /* spinlock held by upper layer, disable TX interrupt */
61 u32 ier = ioread32(port->membase + TIMBUART_IER) & ~TXBAE;
62 iowrite32(ier, port->membase + TIMBUART_IER);
65 static void timbuart_start_tx(struct uart_port *port)
67 struct timbuart_port *uart =
68 container_of(port, struct timbuart_port, port);
70 /* do not transfer anything here -> fire off the tasklet */
71 tasklet_schedule(&uart->tasklet);
74 static unsigned int timbuart_tx_empty(struct uart_port *port)
76 u32 isr = ioread32(port->membase + TIMBUART_ISR);
78 return (isr & TXBE) ? TIOCSER_TEMT : 0;
81 static void timbuart_flush_buffer(struct uart_port *port)
83 if (!timbuart_tx_empty(port)) {
84 u8 ctl = ioread8(port->membase + TIMBUART_CTRL) |
85 TIMBUART_CTRL_FLSHTX;
87 iowrite8(ctl, port->membase + TIMBUART_CTRL);
88 iowrite32(TXBF, port->membase + TIMBUART_ISR);
92 static void timbuart_rx_chars(struct uart_port *port)
94 struct tty_struct *tty = port->state->port.tty;
96 while (ioread32(port->membase + TIMBUART_ISR) & RXDP) {
97 u8 ch = ioread8(port->membase + TIMBUART_RXFIFO);
98 port->icount.rx++;
99 tty_insert_flip_char(tty, ch, TTY_NORMAL);
102 spin_unlock(&port->lock);
103 tty_flip_buffer_push(port->state->port.tty);
104 spin_lock(&port->lock);
106 dev_dbg(port->dev, "%s - total read %d bytes\n",
107 __func__, port->icount.rx);
110 static void timbuart_tx_chars(struct uart_port *port)
112 struct circ_buf *xmit = &port->state->xmit;
114 while (!(ioread32(port->membase + TIMBUART_ISR) & TXBF) &&
115 !uart_circ_empty(xmit)) {
116 iowrite8(xmit->buf[xmit->tail],
117 port->membase + TIMBUART_TXFIFO);
118 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
119 port->icount.tx++;
122 dev_dbg(port->dev,
123 "%s - total written %d bytes, CTL: %x, RTS: %x, baud: %x\n",
124 __func__,
125 port->icount.tx,
126 ioread8(port->membase + TIMBUART_CTRL),
127 port->mctrl & TIOCM_RTS,
128 ioread8(port->membase + TIMBUART_BAUDRATE));
131 static void timbuart_handle_tx_port(struct uart_port *port, u32 isr, u32 *ier)
133 struct timbuart_port *uart =
134 container_of(port, struct timbuart_port, port);
135 struct circ_buf *xmit = &port->state->xmit;
137 if (uart_circ_empty(xmit) || uart_tx_stopped(port))
138 return;
140 if (port->x_char)
141 return;
143 if (isr & TXFLAGS) {
144 timbuart_tx_chars(port);
145 /* clear all TX interrupts */
146 iowrite32(TXFLAGS, port->membase + TIMBUART_ISR);
148 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
149 uart_write_wakeup(port);
150 } else
151 /* Re-enable any tx interrupt */
152 *ier |= uart->last_ier & TXFLAGS;
154 /* enable interrupts if there are chars in the transmit buffer,
155 * Or if we delivered some bytes and want the almost empty interrupt
156 * we wake up the upper layer later when we got the interrupt
157 * to give it some time to go out...
159 if (!uart_circ_empty(xmit))
160 *ier |= TXBAE;
162 dev_dbg(port->dev, "%s - leaving\n", __func__);
165 void timbuart_handle_rx_port(struct uart_port *port, u32 isr, u32 *ier)
167 if (isr & RXFLAGS) {
168 /* Some RX status is set */
169 if (isr & RXBF) {
170 u8 ctl = ioread8(port->membase + TIMBUART_CTRL) |
171 TIMBUART_CTRL_FLSHRX;
172 iowrite8(ctl, port->membase + TIMBUART_CTRL);
173 port->icount.overrun++;
174 } else if (isr & (RXDP))
175 timbuart_rx_chars(port);
177 /* ack all RX interrupts */
178 iowrite32(RXFLAGS, port->membase + TIMBUART_ISR);
181 /* always have the RX interrupts enabled */
182 *ier |= RXBAF | RXBF | RXTT;
184 dev_dbg(port->dev, "%s - leaving\n", __func__);
187 void timbuart_tasklet(unsigned long arg)
189 struct timbuart_port *uart = (struct timbuart_port *)arg;
190 u32 isr, ier = 0;
192 spin_lock(&uart->port.lock);
194 isr = ioread32(uart->port.membase + TIMBUART_ISR);
195 dev_dbg(uart->port.dev, "%s ISR: %x\n", __func__, isr);
197 if (!uart->usedma)
198 timbuart_handle_tx_port(&uart->port, isr, &ier);
200 timbuart_mctrl_check(&uart->port, isr, &ier);
202 if (!uart->usedma)
203 timbuart_handle_rx_port(&uart->port, isr, &ier);
205 iowrite32(ier, uart->port.membase + TIMBUART_IER);
207 spin_unlock(&uart->port.lock);
208 dev_dbg(uart->port.dev, "%s leaving\n", __func__);
211 static unsigned int timbuart_get_mctrl(struct uart_port *port)
213 u8 cts = ioread8(port->membase + TIMBUART_CTRL);
214 dev_dbg(port->dev, "%s - cts %x\n", __func__, cts);
216 if (cts & TIMBUART_CTRL_CTS)
217 return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
218 else
219 return TIOCM_DSR | TIOCM_CAR;
222 static void timbuart_set_mctrl(struct uart_port *port, unsigned int mctrl)
224 dev_dbg(port->dev, "%s - %x\n", __func__, mctrl);
226 if (mctrl & TIOCM_RTS)
227 iowrite8(TIMBUART_CTRL_RTS, port->membase + TIMBUART_CTRL);
228 else
229 iowrite8(0, port->membase + TIMBUART_CTRL);
232 static void timbuart_mctrl_check(struct uart_port *port, u32 isr, u32 *ier)
234 unsigned int cts;
236 if (isr & CTS_DELTA) {
237 /* ack */
238 iowrite32(CTS_DELTA, port->membase + TIMBUART_ISR);
239 cts = timbuart_get_mctrl(port);
240 uart_handle_cts_change(port, cts & TIOCM_CTS);
241 wake_up_interruptible(&port->state->port.delta_msr_wait);
244 *ier |= CTS_DELTA;
247 static void timbuart_enable_ms(struct uart_port *port)
249 /* N/A */
252 static void timbuart_break_ctl(struct uart_port *port, int ctl)
254 /* N/A */
257 static int timbuart_startup(struct uart_port *port)
259 struct timbuart_port *uart =
260 container_of(port, struct timbuart_port, port);
262 dev_dbg(port->dev, "%s\n", __func__);
264 iowrite8(TIMBUART_CTRL_FLSHRX, port->membase + TIMBUART_CTRL);
265 iowrite32(0x1ff, port->membase + TIMBUART_ISR);
266 /* Enable all but TX interrupts */
267 iowrite32(RXBAF | RXBF | RXTT | CTS_DELTA,
268 port->membase + TIMBUART_IER);
270 return request_irq(port->irq, timbuart_handleinterrupt, IRQF_SHARED,
271 "timb-uart", uart);
274 static void timbuart_shutdown(struct uart_port *port)
276 struct timbuart_port *uart =
277 container_of(port, struct timbuart_port, port);
278 dev_dbg(port->dev, "%s\n", __func__);
279 free_irq(port->irq, uart);
280 iowrite32(0, port->membase + TIMBUART_IER);
283 static int get_bindex(int baud)
285 int i;
287 for (i = 0; i < ARRAY_SIZE(baudrates); i++)
288 if (baud <= baudrates[i])
289 return i;
291 return -1;
294 static void timbuart_set_termios(struct uart_port *port,
295 struct ktermios *termios,
296 struct ktermios *old)
298 unsigned int baud;
299 short bindex;
300 unsigned long flags;
302 baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
303 bindex = get_bindex(baud);
304 dev_dbg(port->dev, "%s - bindex %d\n", __func__, bindex);
306 if (bindex < 0)
307 bindex = 0;
308 baud = baudrates[bindex];
310 /* The serial layer calls into this once with old = NULL when setting
311 up initially */
312 if (old)
313 tty_termios_copy_hw(termios, old);
314 tty_termios_encode_baud_rate(termios, baud, baud);
316 spin_lock_irqsave(&port->lock, flags);
317 iowrite8((u8)bindex, port->membase + TIMBUART_BAUDRATE);
318 uart_update_timeout(port, termios->c_cflag, baud);
319 spin_unlock_irqrestore(&port->lock, flags);
322 static const char *timbuart_type(struct uart_port *port)
324 return port->type == PORT_UNKNOWN ? "timbuart" : NULL;
327 /* We do not request/release mappings of the registers here,
328 * currently it's done in the proble function.
330 static void timbuart_release_port(struct uart_port *port)
332 struct platform_device *pdev = to_platform_device(port->dev);
333 int size =
334 resource_size(platform_get_resource(pdev, IORESOURCE_MEM, 0));
336 if (port->flags & UPF_IOREMAP) {
337 iounmap(port->membase);
338 port->membase = NULL;
341 release_mem_region(port->mapbase, size);
344 static int timbuart_request_port(struct uart_port *port)
346 struct platform_device *pdev = to_platform_device(port->dev);
347 int size =
348 resource_size(platform_get_resource(pdev, IORESOURCE_MEM, 0));
350 if (!request_mem_region(port->mapbase, size, "timb-uart"))
351 return -EBUSY;
353 if (port->flags & UPF_IOREMAP) {
354 port->membase = ioremap(port->mapbase, size);
355 if (port->membase == NULL) {
356 release_mem_region(port->mapbase, size);
357 return -ENOMEM;
361 return 0;
364 static irqreturn_t timbuart_handleinterrupt(int irq, void *devid)
366 struct timbuart_port *uart = (struct timbuart_port *)devid;
368 if (ioread8(uart->port.membase + TIMBUART_IPR)) {
369 uart->last_ier = ioread32(uart->port.membase + TIMBUART_IER);
371 /* disable interrupts, the tasklet enables them again */
372 iowrite32(0, uart->port.membase + TIMBUART_IER);
374 /* fire off bottom half */
375 tasklet_schedule(&uart->tasklet);
377 return IRQ_HANDLED;
378 } else
379 return IRQ_NONE;
383 * Configure/autoconfigure the port.
385 static void timbuart_config_port(struct uart_port *port, int flags)
387 if (flags & UART_CONFIG_TYPE) {
388 port->type = PORT_TIMBUART;
389 timbuart_request_port(port);
393 static int timbuart_verify_port(struct uart_port *port,
394 struct serial_struct *ser)
396 /* we don't want the core code to modify any port params */
397 return -EINVAL;
400 static struct uart_ops timbuart_ops = {
401 .tx_empty = timbuart_tx_empty,
402 .set_mctrl = timbuart_set_mctrl,
403 .get_mctrl = timbuart_get_mctrl,
404 .stop_tx = timbuart_stop_tx,
405 .start_tx = timbuart_start_tx,
406 .flush_buffer = timbuart_flush_buffer,
407 .stop_rx = timbuart_stop_rx,
408 .enable_ms = timbuart_enable_ms,
409 .break_ctl = timbuart_break_ctl,
410 .startup = timbuart_startup,
411 .shutdown = timbuart_shutdown,
412 .set_termios = timbuart_set_termios,
413 .type = timbuart_type,
414 .release_port = timbuart_release_port,
415 .request_port = timbuart_request_port,
416 .config_port = timbuart_config_port,
417 .verify_port = timbuart_verify_port
420 static struct uart_driver timbuart_driver = {
421 .owner = THIS_MODULE,
422 .driver_name = "timberdale_uart",
423 .dev_name = "ttyTU",
424 .major = TIMBUART_MAJOR,
425 .minor = TIMBUART_MINOR,
426 .nr = 1
429 static int __devinit timbuart_probe(struct platform_device *dev)
431 int err, irq;
432 struct timbuart_port *uart;
433 struct resource *iomem;
435 dev_dbg(&dev->dev, "%s\n", __func__);
437 uart = kzalloc(sizeof(*uart), GFP_KERNEL);
438 if (!uart) {
439 err = -EINVAL;
440 goto err_mem;
443 uart->usedma = 0;
445 uart->port.uartclk = 3250000 * 16;
446 uart->port.fifosize = TIMBUART_FIFO_SIZE;
447 uart->port.regshift = 2;
448 uart->port.iotype = UPIO_MEM;
449 uart->port.ops = &timbuart_ops;
450 uart->port.irq = 0;
451 uart->port.flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP;
452 uart->port.line = 0;
453 uart->port.dev = &dev->dev;
455 iomem = platform_get_resource(dev, IORESOURCE_MEM, 0);
456 if (!iomem) {
457 err = -ENOMEM;
458 goto err_register;
460 uart->port.mapbase = iomem->start;
461 uart->port.membase = NULL;
463 irq = platform_get_irq(dev, 0);
464 if (irq < 0) {
465 err = -EINVAL;
466 goto err_register;
468 uart->port.irq = irq;
470 tasklet_init(&uart->tasklet, timbuart_tasklet, (unsigned long)uart);
472 err = uart_register_driver(&timbuart_driver);
473 if (err)
474 goto err_register;
476 err = uart_add_one_port(&timbuart_driver, &uart->port);
477 if (err)
478 goto err_add_port;
480 platform_set_drvdata(dev, uart);
482 return 0;
484 err_add_port:
485 uart_unregister_driver(&timbuart_driver);
486 err_register:
487 kfree(uart);
488 err_mem:
489 printk(KERN_ERR "timberdale: Failed to register Timberdale UART: %d\n",
490 err);
492 return err;
495 static int __devexit timbuart_remove(struct platform_device *dev)
497 struct timbuart_port *uart = platform_get_drvdata(dev);
499 tasklet_kill(&uart->tasklet);
500 uart_remove_one_port(&timbuart_driver, &uart->port);
501 uart_unregister_driver(&timbuart_driver);
502 kfree(uart);
504 return 0;
507 static struct platform_driver timbuart_platform_driver = {
508 .driver = {
509 .name = "timb-uart",
510 .owner = THIS_MODULE,
512 .probe = timbuart_probe,
513 .remove = __devexit_p(timbuart_remove),
516 module_platform_driver(timbuart_platform_driver);
518 MODULE_DESCRIPTION("Timberdale UART driver");
519 MODULE_LICENSE("GPL v2");
520 MODULE_ALIAS("platform:timb-uart");