xref: /linux/drivers/tty/serial/omap-serial.c (revision 72787aa866bfa6bcbd259e7a39b2f9a2f412794e)
1 /*
2  * Driver for OMAP-UART controller.
3  * Based on drivers/serial/8250.c
4  *
5  * Copyright (C) 2010 Texas Instruments.
6  *
7  * Authors:
8  *	Govindraj R	<govindraj.raja@ti.com>
9  *	Thara Gopinath	<thara@ti.com>
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * Note: This driver is made separate from 8250 driver as we cannot
17  * over load 8250 driver with omap platform specific configuration for
18  * features like DMA, it makes easier to implement features like DMA and
19  * hardware flow control and software flow control configuration with
20  * this driver as required for the omap-platform.
21  */
22 
23 #if defined(CONFIG_SERIAL_OMAP_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
24 #define SUPPORT_SYSRQ
25 #endif
26 
27 #include <linux/module.h>
28 #include <linux/init.h>
29 #include <linux/console.h>
30 #include <linux/serial_reg.h>
31 #include <linux/delay.h>
32 #include <linux/slab.h>
33 #include <linux/tty.h>
34 #include <linux/tty_flip.h>
35 #include <linux/io.h>
36 #include <linux/dma-mapping.h>
37 #include <linux/clk.h>
38 #include <linux/serial_core.h>
39 #include <linux/irq.h>
40 
41 #include <plat/dma.h>
42 #include <plat/dmtimer.h>
43 #include <plat/omap-serial.h>
44 
45 static struct uart_omap_port *ui[OMAP_MAX_HSUART_PORTS];
46 
47 /* Forward declaration of functions */
48 static void uart_tx_dma_callback(int lch, u16 ch_status, void *data);
49 static void serial_omap_rx_timeout(unsigned long uart_no);
50 static int serial_omap_start_rxdma(struct uart_omap_port *up);
51 
52 static inline unsigned int serial_in(struct uart_omap_port *up, int offset)
53 {
54 	offset <<= up->port.regshift;
55 	return readw(up->port.membase + offset);
56 }
57 
58 static inline void serial_out(struct uart_omap_port *up, int offset, int value)
59 {
60 	offset <<= up->port.regshift;
61 	writew(value, up->port.membase + offset);
62 }
63 
64 static inline void serial_omap_clear_fifos(struct uart_omap_port *up)
65 {
66 	serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
67 	serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
68 		       UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
69 	serial_out(up, UART_FCR, 0);
70 }
71 
72 /*
73  * serial_omap_get_divisor - calculate divisor value
74  * @port: uart port info
75  * @baud: baudrate for which divisor needs to be calculated.
76  *
77  * We have written our own function to get the divisor so as to support
78  * 13x mode. 3Mbps Baudrate as an different divisor.
79  * Reference OMAP TRM Chapter 17:
80  * Table 17-1. UART Mode Baud Rates, Divisor Values, and Error Rates
81  * referring to oversampling - divisor value
82  * baudrate 460,800 to 3,686,400 all have divisor 13
83  * except 3,000,000 which has divisor value 16
84  */
85 static unsigned int
86 serial_omap_get_divisor(struct uart_port *port, unsigned int baud)
87 {
88 	unsigned int divisor;
89 
90 	if (baud > OMAP_MODE13X_SPEED && baud != 3000000)
91 		divisor = 13;
92 	else
93 		divisor = 16;
94 	return port->uartclk/(baud * divisor);
95 }
96 
97 static void serial_omap_stop_rxdma(struct uart_omap_port *up)
98 {
99 	if (up->uart_dma.rx_dma_used) {
100 		del_timer(&up->uart_dma.rx_timer);
101 		omap_stop_dma(up->uart_dma.rx_dma_channel);
102 		omap_free_dma(up->uart_dma.rx_dma_channel);
103 		up->uart_dma.rx_dma_channel = OMAP_UART_DMA_CH_FREE;
104 		up->uart_dma.rx_dma_used = false;
105 	}
106 }
107 
108 static void serial_omap_enable_ms(struct uart_port *port)
109 {
110 	struct uart_omap_port *up = (struct uart_omap_port *)port;
111 
112 	dev_dbg(up->port.dev, "serial_omap_enable_ms+%d\n", up->pdev->id);
113 	up->ier |= UART_IER_MSI;
114 	serial_out(up, UART_IER, up->ier);
115 }
116 
117 static void serial_omap_stop_tx(struct uart_port *port)
118 {
119 	struct uart_omap_port *up = (struct uart_omap_port *)port;
120 
121 	if (up->use_dma &&
122 		up->uart_dma.tx_dma_channel != OMAP_UART_DMA_CH_FREE) {
123 		/*
124 		 * Check if dma is still active. If yes do nothing,
125 		 * return. Else stop dma
126 		 */
127 		if (omap_get_dma_active_status(up->uart_dma.tx_dma_channel))
128 			return;
129 		omap_stop_dma(up->uart_dma.tx_dma_channel);
130 		omap_free_dma(up->uart_dma.tx_dma_channel);
131 		up->uart_dma.tx_dma_channel = OMAP_UART_DMA_CH_FREE;
132 	}
133 
134 	if (up->ier & UART_IER_THRI) {
135 		up->ier &= ~UART_IER_THRI;
136 		serial_out(up, UART_IER, up->ier);
137 	}
138 }
139 
140 static void serial_omap_stop_rx(struct uart_port *port)
141 {
142 	struct uart_omap_port *up = (struct uart_omap_port *)port;
143 
144 	if (up->use_dma)
145 		serial_omap_stop_rxdma(up);
146 	up->ier &= ~UART_IER_RLSI;
147 	up->port.read_status_mask &= ~UART_LSR_DR;
148 	serial_out(up, UART_IER, up->ier);
149 }
150 
151 static inline void receive_chars(struct uart_omap_port *up, int *status)
152 {
153 	struct tty_struct *tty = up->port.state->port.tty;
154 	unsigned int flag;
155 	unsigned char ch, lsr = *status;
156 	int max_count = 256;
157 
158 	do {
159 		if (likely(lsr & UART_LSR_DR))
160 			ch = serial_in(up, UART_RX);
161 		flag = TTY_NORMAL;
162 		up->port.icount.rx++;
163 
164 		if (unlikely(lsr & UART_LSR_BRK_ERROR_BITS)) {
165 			/*
166 			 * For statistics only
167 			 */
168 			if (lsr & UART_LSR_BI) {
169 				lsr &= ~(UART_LSR_FE | UART_LSR_PE);
170 				up->port.icount.brk++;
171 				/*
172 				 * We do the SysRQ and SAK checking
173 				 * here because otherwise the break
174 				 * may get masked by ignore_status_mask
175 				 * or read_status_mask.
176 				 */
177 				if (uart_handle_break(&up->port))
178 					goto ignore_char;
179 			} else if (lsr & UART_LSR_PE) {
180 				up->port.icount.parity++;
181 			} else if (lsr & UART_LSR_FE) {
182 				up->port.icount.frame++;
183 			}
184 
185 			if (lsr & UART_LSR_OE)
186 				up->port.icount.overrun++;
187 
188 			/*
189 			 * Mask off conditions which should be ignored.
190 			 */
191 			lsr &= up->port.read_status_mask;
192 
193 #ifdef CONFIG_SERIAL_OMAP_CONSOLE
194 			if (up->port.line == up->port.cons->index) {
195 				/* Recover the break flag from console xmit */
196 				lsr |= up->lsr_break_flag;
197 			}
198 #endif
199 			if (lsr & UART_LSR_BI)
200 				flag = TTY_BREAK;
201 			else if (lsr & UART_LSR_PE)
202 				flag = TTY_PARITY;
203 			else if (lsr & UART_LSR_FE)
204 				flag = TTY_FRAME;
205 		}
206 
207 		if (uart_handle_sysrq_char(&up->port, ch))
208 			goto ignore_char;
209 		uart_insert_char(&up->port, lsr, UART_LSR_OE, ch, flag);
210 ignore_char:
211 		lsr = serial_in(up, UART_LSR);
212 	} while ((lsr & (UART_LSR_DR | UART_LSR_BI)) && (max_count-- > 0));
213 	spin_unlock(&up->port.lock);
214 	tty_flip_buffer_push(tty);
215 	spin_lock(&up->port.lock);
216 }
217 
218 static void transmit_chars(struct uart_omap_port *up)
219 {
220 	struct circ_buf *xmit = &up->port.state->xmit;
221 	int count;
222 
223 	if (up->port.x_char) {
224 		serial_out(up, UART_TX, up->port.x_char);
225 		up->port.icount.tx++;
226 		up->port.x_char = 0;
227 		return;
228 	}
229 	if (uart_circ_empty(xmit) || uart_tx_stopped(&up->port)) {
230 		serial_omap_stop_tx(&up->port);
231 		return;
232 	}
233 	count = up->port.fifosize / 4;
234 	do {
235 		serial_out(up, UART_TX, xmit->buf[xmit->tail]);
236 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
237 		up->port.icount.tx++;
238 		if (uart_circ_empty(xmit))
239 			break;
240 	} while (--count > 0);
241 
242 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
243 		uart_write_wakeup(&up->port);
244 
245 	if (uart_circ_empty(xmit))
246 		serial_omap_stop_tx(&up->port);
247 }
248 
249 static inline void serial_omap_enable_ier_thri(struct uart_omap_port *up)
250 {
251 	if (!(up->ier & UART_IER_THRI)) {
252 		up->ier |= UART_IER_THRI;
253 		serial_out(up, UART_IER, up->ier);
254 	}
255 }
256 
257 static void serial_omap_start_tx(struct uart_port *port)
258 {
259 	struct uart_omap_port *up = (struct uart_omap_port *)port;
260 	struct circ_buf *xmit;
261 	unsigned int start;
262 	int ret = 0;
263 
264 	if (!up->use_dma) {
265 		serial_omap_enable_ier_thri(up);
266 		return;
267 	}
268 
269 	if (up->uart_dma.tx_dma_used)
270 		return;
271 
272 	xmit = &up->port.state->xmit;
273 
274 	if (up->uart_dma.tx_dma_channel == OMAP_UART_DMA_CH_FREE) {
275 		ret = omap_request_dma(up->uart_dma.uart_dma_tx,
276 				"UART Tx DMA",
277 				(void *)uart_tx_dma_callback, up,
278 				&(up->uart_dma.tx_dma_channel));
279 
280 		if (ret < 0) {
281 			serial_omap_enable_ier_thri(up);
282 			return;
283 		}
284 	}
285 	spin_lock(&(up->uart_dma.tx_lock));
286 	up->uart_dma.tx_dma_used = true;
287 	spin_unlock(&(up->uart_dma.tx_lock));
288 
289 	start = up->uart_dma.tx_buf_dma_phys +
290 				(xmit->tail & (UART_XMIT_SIZE - 1));
291 
292 	up->uart_dma.tx_buf_size = uart_circ_chars_pending(xmit);
293 	/*
294 	 * It is a circular buffer. See if the buffer has wounded back.
295 	 * If yes it will have to be transferred in two separate dma
296 	 * transfers
297 	 */
298 	if (start + up->uart_dma.tx_buf_size >=
299 			up->uart_dma.tx_buf_dma_phys + UART_XMIT_SIZE)
300 		up->uart_dma.tx_buf_size =
301 			(up->uart_dma.tx_buf_dma_phys +
302 			UART_XMIT_SIZE) - start;
303 
304 	omap_set_dma_dest_params(up->uart_dma.tx_dma_channel, 0,
305 				OMAP_DMA_AMODE_CONSTANT,
306 				up->uart_dma.uart_base, 0, 0);
307 	omap_set_dma_src_params(up->uart_dma.tx_dma_channel, 0,
308 				OMAP_DMA_AMODE_POST_INC, start, 0, 0);
309 	omap_set_dma_transfer_params(up->uart_dma.tx_dma_channel,
310 				OMAP_DMA_DATA_TYPE_S8,
311 				up->uart_dma.tx_buf_size, 1,
312 				OMAP_DMA_SYNC_ELEMENT,
313 				up->uart_dma.uart_dma_tx, 0);
314 	/* FIXME: Cache maintenance needed here? */
315 	omap_start_dma(up->uart_dma.tx_dma_channel);
316 }
317 
318 static unsigned int check_modem_status(struct uart_omap_port *up)
319 {
320 	unsigned int status;
321 
322 	status = serial_in(up, UART_MSR);
323 	status |= up->msr_saved_flags;
324 	up->msr_saved_flags = 0;
325 	if ((status & UART_MSR_ANY_DELTA) == 0)
326 		return status;
327 
328 	if (status & UART_MSR_ANY_DELTA && up->ier & UART_IER_MSI &&
329 	    up->port.state != NULL) {
330 		if (status & UART_MSR_TERI)
331 			up->port.icount.rng++;
332 		if (status & UART_MSR_DDSR)
333 			up->port.icount.dsr++;
334 		if (status & UART_MSR_DDCD)
335 			uart_handle_dcd_change
336 				(&up->port, status & UART_MSR_DCD);
337 		if (status & UART_MSR_DCTS)
338 			uart_handle_cts_change
339 				(&up->port, status & UART_MSR_CTS);
340 		wake_up_interruptible(&up->port.state->port.delta_msr_wait);
341 	}
342 
343 	return status;
344 }
345 
346 /**
347  * serial_omap_irq() - This handles the interrupt from one port
348  * @irq: uart port irq number
349  * @dev_id: uart port info
350  */
351 static inline irqreturn_t serial_omap_irq(int irq, void *dev_id)
352 {
353 	struct uart_omap_port *up = dev_id;
354 	unsigned int iir, lsr;
355 	unsigned long flags;
356 
357 	iir = serial_in(up, UART_IIR);
358 	if (iir & UART_IIR_NO_INT)
359 		return IRQ_NONE;
360 
361 	spin_lock_irqsave(&up->port.lock, flags);
362 	lsr = serial_in(up, UART_LSR);
363 	if (iir & UART_IIR_RLSI) {
364 		if (!up->use_dma) {
365 			if (lsr & UART_LSR_DR)
366 				receive_chars(up, &lsr);
367 		} else {
368 			up->ier &= ~(UART_IER_RDI | UART_IER_RLSI);
369 			serial_out(up, UART_IER, up->ier);
370 			if ((serial_omap_start_rxdma(up) != 0) &&
371 					(lsr & UART_LSR_DR))
372 				receive_chars(up, &lsr);
373 		}
374 	}
375 
376 	check_modem_status(up);
377 	if ((lsr & UART_LSR_THRE) && (iir & UART_IIR_THRI))
378 		transmit_chars(up);
379 
380 	spin_unlock_irqrestore(&up->port.lock, flags);
381 	up->port_activity = jiffies;
382 	return IRQ_HANDLED;
383 }
384 
385 static unsigned int serial_omap_tx_empty(struct uart_port *port)
386 {
387 	struct uart_omap_port *up = (struct uart_omap_port *)port;
388 	unsigned long flags = 0;
389 	unsigned int ret = 0;
390 
391 	dev_dbg(up->port.dev, "serial_omap_tx_empty+%d\n", up->pdev->id);
392 	spin_lock_irqsave(&up->port.lock, flags);
393 	ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
394 	spin_unlock_irqrestore(&up->port.lock, flags);
395 
396 	return ret;
397 }
398 
399 static unsigned int serial_omap_get_mctrl(struct uart_port *port)
400 {
401 	struct uart_omap_port *up = (struct uart_omap_port *)port;
402 	unsigned char status;
403 	unsigned int ret = 0;
404 
405 	status = check_modem_status(up);
406 	dev_dbg(up->port.dev, "serial_omap_get_mctrl+%d\n", up->pdev->id);
407 
408 	if (status & UART_MSR_DCD)
409 		ret |= TIOCM_CAR;
410 	if (status & UART_MSR_RI)
411 		ret |= TIOCM_RNG;
412 	if (status & UART_MSR_DSR)
413 		ret |= TIOCM_DSR;
414 	if (status & UART_MSR_CTS)
415 		ret |= TIOCM_CTS;
416 	return ret;
417 }
418 
419 static void serial_omap_set_mctrl(struct uart_port *port, unsigned int mctrl)
420 {
421 	struct uart_omap_port *up = (struct uart_omap_port *)port;
422 	unsigned char mcr = 0;
423 
424 	dev_dbg(up->port.dev, "serial_omap_set_mctrl+%d\n", up->pdev->id);
425 	if (mctrl & TIOCM_RTS)
426 		mcr |= UART_MCR_RTS;
427 	if (mctrl & TIOCM_DTR)
428 		mcr |= UART_MCR_DTR;
429 	if (mctrl & TIOCM_OUT1)
430 		mcr |= UART_MCR_OUT1;
431 	if (mctrl & TIOCM_OUT2)
432 		mcr |= UART_MCR_OUT2;
433 	if (mctrl & TIOCM_LOOP)
434 		mcr |= UART_MCR_LOOP;
435 
436 	mcr |= up->mcr;
437 	serial_out(up, UART_MCR, mcr);
438 }
439 
440 static void serial_omap_break_ctl(struct uart_port *port, int break_state)
441 {
442 	struct uart_omap_port *up = (struct uart_omap_port *)port;
443 	unsigned long flags = 0;
444 
445 	dev_dbg(up->port.dev, "serial_omap_break_ctl+%d\n", up->pdev->id);
446 	spin_lock_irqsave(&up->port.lock, flags);
447 	if (break_state == -1)
448 		up->lcr |= UART_LCR_SBC;
449 	else
450 		up->lcr &= ~UART_LCR_SBC;
451 	serial_out(up, UART_LCR, up->lcr);
452 	spin_unlock_irqrestore(&up->port.lock, flags);
453 }
454 
455 static int serial_omap_startup(struct uart_port *port)
456 {
457 	struct uart_omap_port *up = (struct uart_omap_port *)port;
458 	unsigned long flags = 0;
459 	int retval;
460 
461 	/*
462 	 * Allocate the IRQ
463 	 */
464 	retval = request_irq(up->port.irq, serial_omap_irq, up->port.irqflags,
465 				up->name, up);
466 	if (retval)
467 		return retval;
468 
469 	dev_dbg(up->port.dev, "serial_omap_startup+%d\n", up->pdev->id);
470 
471 	/*
472 	 * Clear the FIFO buffers and disable them.
473 	 * (they will be reenabled in set_termios())
474 	 */
475 	serial_omap_clear_fifos(up);
476 	/* For Hardware flow control */
477 	serial_out(up, UART_MCR, UART_MCR_RTS);
478 
479 	/*
480 	 * Clear the interrupt registers.
481 	 */
482 	(void) serial_in(up, UART_LSR);
483 	if (serial_in(up, UART_LSR) & UART_LSR_DR)
484 		(void) serial_in(up, UART_RX);
485 	(void) serial_in(up, UART_IIR);
486 	(void) serial_in(up, UART_MSR);
487 
488 	/*
489 	 * Now, initialize the UART
490 	 */
491 	serial_out(up, UART_LCR, UART_LCR_WLEN8);
492 	spin_lock_irqsave(&up->port.lock, flags);
493 	/*
494 	 * Most PC uarts need OUT2 raised to enable interrupts.
495 	 */
496 	up->port.mctrl |= TIOCM_OUT2;
497 	serial_omap_set_mctrl(&up->port, up->port.mctrl);
498 	spin_unlock_irqrestore(&up->port.lock, flags);
499 
500 	up->msr_saved_flags = 0;
501 	if (up->use_dma) {
502 		free_page((unsigned long)up->port.state->xmit.buf);
503 		up->port.state->xmit.buf = dma_alloc_coherent(NULL,
504 			UART_XMIT_SIZE,
505 			(dma_addr_t *)&(up->uart_dma.tx_buf_dma_phys),
506 			0);
507 		init_timer(&(up->uart_dma.rx_timer));
508 		up->uart_dma.rx_timer.function = serial_omap_rx_timeout;
509 		up->uart_dma.rx_timer.data = up->pdev->id;
510 		/* Currently the buffer size is 4KB. Can increase it */
511 		up->uart_dma.rx_buf = dma_alloc_coherent(NULL,
512 			up->uart_dma.rx_buf_size,
513 			(dma_addr_t *)&(up->uart_dma.rx_buf_dma_phys), 0);
514 	}
515 	/*
516 	 * Finally, enable interrupts. Note: Modem status interrupts
517 	 * are set via set_termios(), which will be occurring imminently
518 	 * anyway, so we don't enable them here.
519 	 */
520 	up->ier = UART_IER_RLSI | UART_IER_RDI;
521 	serial_out(up, UART_IER, up->ier);
522 
523 	/* Enable module level wake up */
524 	serial_out(up, UART_OMAP_WER, OMAP_UART_WER_MOD_WKUP);
525 
526 	up->port_activity = jiffies;
527 	return 0;
528 }
529 
530 static void serial_omap_shutdown(struct uart_port *port)
531 {
532 	struct uart_omap_port *up = (struct uart_omap_port *)port;
533 	unsigned long flags = 0;
534 
535 	dev_dbg(up->port.dev, "serial_omap_shutdown+%d\n", up->pdev->id);
536 	/*
537 	 * Disable interrupts from this port
538 	 */
539 	up->ier = 0;
540 	serial_out(up, UART_IER, 0);
541 
542 	spin_lock_irqsave(&up->port.lock, flags);
543 	up->port.mctrl &= ~TIOCM_OUT2;
544 	serial_omap_set_mctrl(&up->port, up->port.mctrl);
545 	spin_unlock_irqrestore(&up->port.lock, flags);
546 
547 	/*
548 	 * Disable break condition and FIFOs
549 	 */
550 	serial_out(up, UART_LCR, serial_in(up, UART_LCR) & ~UART_LCR_SBC);
551 	serial_omap_clear_fifos(up);
552 
553 	/*
554 	 * Read data port to reset things, and then free the irq
555 	 */
556 	if (serial_in(up, UART_LSR) & UART_LSR_DR)
557 		(void) serial_in(up, UART_RX);
558 	if (up->use_dma) {
559 		dma_free_coherent(up->port.dev,
560 			UART_XMIT_SIZE,	up->port.state->xmit.buf,
561 			up->uart_dma.tx_buf_dma_phys);
562 		up->port.state->xmit.buf = NULL;
563 		serial_omap_stop_rx(port);
564 		dma_free_coherent(up->port.dev,
565 			up->uart_dma.rx_buf_size, up->uart_dma.rx_buf,
566 			up->uart_dma.rx_buf_dma_phys);
567 		up->uart_dma.rx_buf = NULL;
568 	}
569 	free_irq(up->port.irq, up);
570 }
571 
572 static inline void
573 serial_omap_configure_xonxoff
574 		(struct uart_omap_port *up, struct ktermios *termios)
575 {
576 	unsigned char efr = 0;
577 
578 	up->lcr = serial_in(up, UART_LCR);
579 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
580 	up->efr = serial_in(up, UART_EFR);
581 	serial_out(up, UART_EFR, up->efr & ~UART_EFR_ECB);
582 
583 	serial_out(up, UART_XON1, termios->c_cc[VSTART]);
584 	serial_out(up, UART_XOFF1, termios->c_cc[VSTOP]);
585 
586 	/* clear SW control mode bits */
587 	efr = up->efr;
588 	efr &= OMAP_UART_SW_CLR;
589 
590 	/*
591 	 * IXON Flag:
592 	 * Enable XON/XOFF flow control on output.
593 	 * Transmit XON1, XOFF1
594 	 */
595 	if (termios->c_iflag & IXON)
596 		efr |= OMAP_UART_SW_TX;
597 
598 	/*
599 	 * IXOFF Flag:
600 	 * Enable XON/XOFF flow control on input.
601 	 * Receiver compares XON1, XOFF1.
602 	 */
603 	if (termios->c_iflag & IXOFF)
604 		efr |= OMAP_UART_SW_RX;
605 
606 	serial_out(up, UART_EFR, up->efr | UART_EFR_ECB);
607 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
608 
609 	up->mcr = serial_in(up, UART_MCR);
610 
611 	/*
612 	 * IXANY Flag:
613 	 * Enable any character to restart output.
614 	 * Operation resumes after receiving any
615 	 * character after recognition of the XOFF character
616 	 */
617 	if (termios->c_iflag & IXANY)
618 		up->mcr |= UART_MCR_XONANY;
619 
620 	serial_out(up, UART_MCR, up->mcr | UART_MCR_TCRTLR);
621 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
622 	serial_out(up, UART_TI752_TCR, OMAP_UART_TCR_TRIG);
623 	/* Enable special char function UARTi.EFR_REG[5] and
624 	 * load the new software flow control mode IXON or IXOFF
625 	 * and restore the UARTi.EFR_REG[4] ENHANCED_EN value.
626 	 */
627 	serial_out(up, UART_EFR, efr | UART_EFR_SCD);
628 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
629 
630 	serial_out(up, UART_MCR, up->mcr & ~UART_MCR_TCRTLR);
631 	serial_out(up, UART_LCR, up->lcr);
632 }
633 
634 static void
635 serial_omap_set_termios(struct uart_port *port, struct ktermios *termios,
636 			struct ktermios *old)
637 {
638 	struct uart_omap_port *up = (struct uart_omap_port *)port;
639 	unsigned char cval = 0;
640 	unsigned char efr = 0;
641 	unsigned long flags = 0;
642 	unsigned int baud, quot;
643 
644 	switch (termios->c_cflag & CSIZE) {
645 	case CS5:
646 		cval = UART_LCR_WLEN5;
647 		break;
648 	case CS6:
649 		cval = UART_LCR_WLEN6;
650 		break;
651 	case CS7:
652 		cval = UART_LCR_WLEN7;
653 		break;
654 	default:
655 	case CS8:
656 		cval = UART_LCR_WLEN8;
657 		break;
658 	}
659 
660 	if (termios->c_cflag & CSTOPB)
661 		cval |= UART_LCR_STOP;
662 	if (termios->c_cflag & PARENB)
663 		cval |= UART_LCR_PARITY;
664 	if (!(termios->c_cflag & PARODD))
665 		cval |= UART_LCR_EPAR;
666 
667 	/*
668 	 * Ask the core to calculate the divisor for us.
669 	 */
670 
671 	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/13);
672 	quot = serial_omap_get_divisor(port, baud);
673 
674 	up->fcr = UART_FCR_R_TRIG_01 | UART_FCR_T_TRIG_01 |
675 			UART_FCR_ENABLE_FIFO;
676 	if (up->use_dma)
677 		up->fcr |= UART_FCR_DMA_SELECT;
678 
679 	/*
680 	 * Ok, we're now changing the port state. Do it with
681 	 * interrupts disabled.
682 	 */
683 	spin_lock_irqsave(&up->port.lock, flags);
684 
685 	/*
686 	 * Update the per-port timeout.
687 	 */
688 	uart_update_timeout(port, termios->c_cflag, baud);
689 
690 	up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
691 	if (termios->c_iflag & INPCK)
692 		up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE;
693 	if (termios->c_iflag & (BRKINT | PARMRK))
694 		up->port.read_status_mask |= UART_LSR_BI;
695 
696 	/*
697 	 * Characters to ignore
698 	 */
699 	up->port.ignore_status_mask = 0;
700 	if (termios->c_iflag & IGNPAR)
701 		up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
702 	if (termios->c_iflag & IGNBRK) {
703 		up->port.ignore_status_mask |= UART_LSR_BI;
704 		/*
705 		 * If we're ignoring parity and break indicators,
706 		 * ignore overruns too (for real raw support).
707 		 */
708 		if (termios->c_iflag & IGNPAR)
709 			up->port.ignore_status_mask |= UART_LSR_OE;
710 	}
711 
712 	/*
713 	 * ignore all characters if CREAD is not set
714 	 */
715 	if ((termios->c_cflag & CREAD) == 0)
716 		up->port.ignore_status_mask |= UART_LSR_DR;
717 
718 	/*
719 	 * Modem status interrupts
720 	 */
721 	up->ier &= ~UART_IER_MSI;
722 	if (UART_ENABLE_MS(&up->port, termios->c_cflag))
723 		up->ier |= UART_IER_MSI;
724 	serial_out(up, UART_IER, up->ier);
725 	serial_out(up, UART_LCR, cval);		/* reset DLAB */
726 
727 	/* FIFOs and DMA Settings */
728 
729 	/* FCR can be changed only when the
730 	 * baud clock is not running
731 	 * DLL_REG and DLH_REG set to 0.
732 	 */
733 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
734 	serial_out(up, UART_DLL, 0);
735 	serial_out(up, UART_DLM, 0);
736 	serial_out(up, UART_LCR, 0);
737 
738 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
739 
740 	up->efr = serial_in(up, UART_EFR);
741 	serial_out(up, UART_EFR, up->efr | UART_EFR_ECB);
742 
743 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
744 	up->mcr = serial_in(up, UART_MCR);
745 	serial_out(up, UART_MCR, up->mcr | UART_MCR_TCRTLR);
746 	/* FIFO ENABLE, DMA MODE */
747 	serial_out(up, UART_FCR, up->fcr);
748 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
749 
750 	if (up->use_dma) {
751 		serial_out(up, UART_TI752_TLR, 0);
752 		serial_out(up, UART_OMAP_SCR,
753 			(UART_FCR_TRIGGER_4 | UART_FCR_TRIGGER_8));
754 	}
755 
756 	serial_out(up, UART_EFR, up->efr);
757 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
758 	serial_out(up, UART_MCR, up->mcr);
759 
760 	/* Protocol, Baud Rate, and Interrupt Settings */
761 
762 	serial_out(up, UART_OMAP_MDR1, UART_OMAP_MDR1_DISABLE);
763 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
764 
765 	up->efr = serial_in(up, UART_EFR);
766 	serial_out(up, UART_EFR, up->efr | UART_EFR_ECB);
767 
768 	serial_out(up, UART_LCR, 0);
769 	serial_out(up, UART_IER, 0);
770 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
771 
772 	serial_out(up, UART_DLL, quot & 0xff);          /* LS of divisor */
773 	serial_out(up, UART_DLM, quot >> 8);            /* MS of divisor */
774 
775 	serial_out(up, UART_LCR, 0);
776 	serial_out(up, UART_IER, up->ier);
777 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
778 
779 	serial_out(up, UART_EFR, up->efr);
780 	serial_out(up, UART_LCR, cval);
781 
782 	if (baud > 230400 && baud != 3000000)
783 		serial_out(up, UART_OMAP_MDR1, UART_OMAP_MDR1_13X_MODE);
784 	else
785 		serial_out(up, UART_OMAP_MDR1, UART_OMAP_MDR1_16X_MODE);
786 
787 	/* Hardware Flow Control Configuration */
788 
789 	if (termios->c_cflag & CRTSCTS) {
790 		efr |= (UART_EFR_CTS | UART_EFR_RTS);
791 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
792 
793 		up->mcr = serial_in(up, UART_MCR);
794 		serial_out(up, UART_MCR, up->mcr | UART_MCR_TCRTLR);
795 
796 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
797 		up->efr = serial_in(up, UART_EFR);
798 		serial_out(up, UART_EFR, up->efr | UART_EFR_ECB);
799 
800 		serial_out(up, UART_TI752_TCR, OMAP_UART_TCR_TRIG);
801 		serial_out(up, UART_EFR, efr); /* Enable AUTORTS and AUTOCTS */
802 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
803 		serial_out(up, UART_MCR, up->mcr | UART_MCR_RTS);
804 		serial_out(up, UART_LCR, cval);
805 	}
806 
807 	serial_omap_set_mctrl(&up->port, up->port.mctrl);
808 	/* Software Flow Control Configuration */
809 	serial_omap_configure_xonxoff(up, termios);
810 
811 	spin_unlock_irqrestore(&up->port.lock, flags);
812 	dev_dbg(up->port.dev, "serial_omap_set_termios+%d\n", up->pdev->id);
813 }
814 
815 static void
816 serial_omap_pm(struct uart_port *port, unsigned int state,
817 	       unsigned int oldstate)
818 {
819 	struct uart_omap_port *up = (struct uart_omap_port *)port;
820 	unsigned char efr;
821 
822 	dev_dbg(up->port.dev, "serial_omap_pm+%d\n", up->pdev->id);
823 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
824 	efr = serial_in(up, UART_EFR);
825 	serial_out(up, UART_EFR, efr | UART_EFR_ECB);
826 	serial_out(up, UART_LCR, 0);
827 
828 	serial_out(up, UART_IER, (state != 0) ? UART_IERX_SLEEP : 0);
829 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
830 	serial_out(up, UART_EFR, efr);
831 	serial_out(up, UART_LCR, 0);
832 }
833 
834 static void serial_omap_release_port(struct uart_port *port)
835 {
836 	dev_dbg(port->dev, "serial_omap_release_port+\n");
837 }
838 
839 static int serial_omap_request_port(struct uart_port *port)
840 {
841 	dev_dbg(port->dev, "serial_omap_request_port+\n");
842 	return 0;
843 }
844 
845 static void serial_omap_config_port(struct uart_port *port, int flags)
846 {
847 	struct uart_omap_port *up = (struct uart_omap_port *)port;
848 
849 	dev_dbg(up->port.dev, "serial_omap_config_port+%d\n",
850 							up->pdev->id);
851 	up->port.type = PORT_OMAP;
852 }
853 
854 static int
855 serial_omap_verify_port(struct uart_port *port, struct serial_struct *ser)
856 {
857 	/* we don't want the core code to modify any port params */
858 	dev_dbg(port->dev, "serial_omap_verify_port+\n");
859 	return -EINVAL;
860 }
861 
862 static const char *
863 serial_omap_type(struct uart_port *port)
864 {
865 	struct uart_omap_port *up = (struct uart_omap_port *)port;
866 
867 	dev_dbg(up->port.dev, "serial_omap_type+%d\n", up->pdev->id);
868 	return up->name;
869 }
870 
871 #define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
872 
873 static inline void wait_for_xmitr(struct uart_omap_port *up)
874 {
875 	unsigned int status, tmout = 10000;
876 
877 	/* Wait up to 10ms for the character(s) to be sent. */
878 	do {
879 		status = serial_in(up, UART_LSR);
880 
881 		if (status & UART_LSR_BI)
882 			up->lsr_break_flag = UART_LSR_BI;
883 
884 		if (--tmout == 0)
885 			break;
886 		udelay(1);
887 	} while ((status & BOTH_EMPTY) != BOTH_EMPTY);
888 
889 	/* Wait up to 1s for flow control if necessary */
890 	if (up->port.flags & UPF_CONS_FLOW) {
891 		tmout = 1000000;
892 		for (tmout = 1000000; tmout; tmout--) {
893 			unsigned int msr = serial_in(up, UART_MSR);
894 
895 			up->msr_saved_flags |= msr & MSR_SAVE_FLAGS;
896 			if (msr & UART_MSR_CTS)
897 				break;
898 
899 			udelay(1);
900 		}
901 	}
902 }
903 
904 #ifdef CONFIG_CONSOLE_POLL
905 
906 static void serial_omap_poll_put_char(struct uart_port *port, unsigned char ch)
907 {
908 	struct uart_omap_port *up = (struct uart_omap_port *)port;
909 	wait_for_xmitr(up);
910 	serial_out(up, UART_TX, ch);
911 }
912 
913 static int serial_omap_poll_get_char(struct uart_port *port)
914 {
915 	struct uart_omap_port *up = (struct uart_omap_port *)port;
916 	unsigned int status = serial_in(up, UART_LSR);
917 
918 	if (!(status & UART_LSR_DR))
919 		return NO_POLL_CHAR;
920 
921 	return serial_in(up, UART_RX);
922 }
923 
924 #endif /* CONFIG_CONSOLE_POLL */
925 
926 #ifdef CONFIG_SERIAL_OMAP_CONSOLE
927 
928 static struct uart_omap_port *serial_omap_console_ports[4];
929 
930 static struct uart_driver serial_omap_reg;
931 
932 static void serial_omap_console_putchar(struct uart_port *port, int ch)
933 {
934 	struct uart_omap_port *up = (struct uart_omap_port *)port;
935 
936 	wait_for_xmitr(up);
937 	serial_out(up, UART_TX, ch);
938 }
939 
940 static void
941 serial_omap_console_write(struct console *co, const char *s,
942 		unsigned int count)
943 {
944 	struct uart_omap_port *up = serial_omap_console_ports[co->index];
945 	unsigned long flags;
946 	unsigned int ier;
947 	int locked = 1;
948 
949 	local_irq_save(flags);
950 	if (up->port.sysrq)
951 		locked = 0;
952 	else if (oops_in_progress)
953 		locked = spin_trylock(&up->port.lock);
954 	else
955 		spin_lock(&up->port.lock);
956 
957 	/*
958 	 * First save the IER then disable the interrupts
959 	 */
960 	ier = serial_in(up, UART_IER);
961 	serial_out(up, UART_IER, 0);
962 
963 	uart_console_write(&up->port, s, count, serial_omap_console_putchar);
964 
965 	/*
966 	 * Finally, wait for transmitter to become empty
967 	 * and restore the IER
968 	 */
969 	wait_for_xmitr(up);
970 	serial_out(up, UART_IER, ier);
971 	/*
972 	 * The receive handling will happen properly because the
973 	 * receive ready bit will still be set; it is not cleared
974 	 * on read.  However, modem control will not, we must
975 	 * call it if we have saved something in the saved flags
976 	 * while processing with interrupts off.
977 	 */
978 	if (up->msr_saved_flags)
979 		check_modem_status(up);
980 
981 	if (locked)
982 		spin_unlock(&up->port.lock);
983 	local_irq_restore(flags);
984 }
985 
986 static int __init
987 serial_omap_console_setup(struct console *co, char *options)
988 {
989 	struct uart_omap_port *up;
990 	int baud = 115200;
991 	int bits = 8;
992 	int parity = 'n';
993 	int flow = 'n';
994 
995 	if (serial_omap_console_ports[co->index] == NULL)
996 		return -ENODEV;
997 	up = serial_omap_console_ports[co->index];
998 
999 	if (options)
1000 		uart_parse_options(options, &baud, &parity, &bits, &flow);
1001 
1002 	return uart_set_options(&up->port, co, baud, parity, bits, flow);
1003 }
1004 
1005 static struct console serial_omap_console = {
1006 	.name		= OMAP_SERIAL_NAME,
1007 	.write		= serial_omap_console_write,
1008 	.device		= uart_console_device,
1009 	.setup		= serial_omap_console_setup,
1010 	.flags		= CON_PRINTBUFFER,
1011 	.index		= -1,
1012 	.data		= &serial_omap_reg,
1013 };
1014 
1015 static void serial_omap_add_console_port(struct uart_omap_port *up)
1016 {
1017 	serial_omap_console_ports[up->pdev->id] = up;
1018 }
1019 
1020 #define OMAP_CONSOLE	(&serial_omap_console)
1021 
1022 #else
1023 
1024 #define OMAP_CONSOLE	NULL
1025 
1026 static inline void serial_omap_add_console_port(struct uart_omap_port *up)
1027 {}
1028 
1029 #endif
1030 
1031 static struct uart_ops serial_omap_pops = {
1032 	.tx_empty	= serial_omap_tx_empty,
1033 	.set_mctrl	= serial_omap_set_mctrl,
1034 	.get_mctrl	= serial_omap_get_mctrl,
1035 	.stop_tx	= serial_omap_stop_tx,
1036 	.start_tx	= serial_omap_start_tx,
1037 	.stop_rx	= serial_omap_stop_rx,
1038 	.enable_ms	= serial_omap_enable_ms,
1039 	.break_ctl	= serial_omap_break_ctl,
1040 	.startup	= serial_omap_startup,
1041 	.shutdown	= serial_omap_shutdown,
1042 	.set_termios	= serial_omap_set_termios,
1043 	.pm		= serial_omap_pm,
1044 	.type		= serial_omap_type,
1045 	.release_port	= serial_omap_release_port,
1046 	.request_port	= serial_omap_request_port,
1047 	.config_port	= serial_omap_config_port,
1048 	.verify_port	= serial_omap_verify_port,
1049 #ifdef CONFIG_CONSOLE_POLL
1050 	.poll_put_char  = serial_omap_poll_put_char,
1051 	.poll_get_char  = serial_omap_poll_get_char,
1052 #endif
1053 };
1054 
1055 static struct uart_driver serial_omap_reg = {
1056 	.owner		= THIS_MODULE,
1057 	.driver_name	= "OMAP-SERIAL",
1058 	.dev_name	= OMAP_SERIAL_NAME,
1059 	.nr		= OMAP_MAX_HSUART_PORTS,
1060 	.cons		= OMAP_CONSOLE,
1061 };
1062 
1063 static int
1064 serial_omap_suspend(struct platform_device *pdev, pm_message_t state)
1065 {
1066 	struct uart_omap_port *up = platform_get_drvdata(pdev);
1067 
1068 	if (up)
1069 		uart_suspend_port(&serial_omap_reg, &up->port);
1070 	return 0;
1071 }
1072 
1073 static int serial_omap_resume(struct platform_device *dev)
1074 {
1075 	struct uart_omap_port *up = platform_get_drvdata(dev);
1076 
1077 	if (up)
1078 		uart_resume_port(&serial_omap_reg, &up->port);
1079 	return 0;
1080 }
1081 
1082 static void serial_omap_rx_timeout(unsigned long uart_no)
1083 {
1084 	struct uart_omap_port *up = ui[uart_no];
1085 	unsigned int curr_dma_pos, curr_transmitted_size;
1086 	int ret = 0;
1087 
1088 	curr_dma_pos = omap_get_dma_dst_pos(up->uart_dma.rx_dma_channel);
1089 	if ((curr_dma_pos == up->uart_dma.prev_rx_dma_pos) ||
1090 			     (curr_dma_pos == 0)) {
1091 		if (jiffies_to_msecs(jiffies - up->port_activity) <
1092 							RX_TIMEOUT) {
1093 			mod_timer(&up->uart_dma.rx_timer, jiffies +
1094 				usecs_to_jiffies(up->uart_dma.rx_timeout));
1095 		} else {
1096 			serial_omap_stop_rxdma(up);
1097 			up->ier |= (UART_IER_RDI | UART_IER_RLSI);
1098 			serial_out(up, UART_IER, up->ier);
1099 		}
1100 		return;
1101 	}
1102 
1103 	curr_transmitted_size = curr_dma_pos -
1104 					up->uart_dma.prev_rx_dma_pos;
1105 	up->port.icount.rx += curr_transmitted_size;
1106 	tty_insert_flip_string(up->port.state->port.tty,
1107 			up->uart_dma.rx_buf +
1108 			(up->uart_dma.prev_rx_dma_pos -
1109 			up->uart_dma.rx_buf_dma_phys),
1110 			curr_transmitted_size);
1111 	tty_flip_buffer_push(up->port.state->port.tty);
1112 	up->uart_dma.prev_rx_dma_pos = curr_dma_pos;
1113 	if (up->uart_dma.rx_buf_size +
1114 			up->uart_dma.rx_buf_dma_phys == curr_dma_pos) {
1115 		ret = serial_omap_start_rxdma(up);
1116 		if (ret < 0) {
1117 			serial_omap_stop_rxdma(up);
1118 			up->ier |= (UART_IER_RDI | UART_IER_RLSI);
1119 			serial_out(up, UART_IER, up->ier);
1120 		}
1121 	} else  {
1122 		mod_timer(&up->uart_dma.rx_timer, jiffies +
1123 			usecs_to_jiffies(up->uart_dma.rx_timeout));
1124 	}
1125 	up->port_activity = jiffies;
1126 }
1127 
1128 static void uart_rx_dma_callback(int lch, u16 ch_status, void *data)
1129 {
1130 	return;
1131 }
1132 
1133 static int serial_omap_start_rxdma(struct uart_omap_port *up)
1134 {
1135 	int ret = 0;
1136 
1137 	if (up->uart_dma.rx_dma_channel == -1) {
1138 		ret = omap_request_dma(up->uart_dma.uart_dma_rx,
1139 				"UART Rx DMA",
1140 				(void *)uart_rx_dma_callback, up,
1141 				&(up->uart_dma.rx_dma_channel));
1142 		if (ret < 0)
1143 			return ret;
1144 
1145 		omap_set_dma_src_params(up->uart_dma.rx_dma_channel, 0,
1146 				OMAP_DMA_AMODE_CONSTANT,
1147 				up->uart_dma.uart_base, 0, 0);
1148 		omap_set_dma_dest_params(up->uart_dma.rx_dma_channel, 0,
1149 				OMAP_DMA_AMODE_POST_INC,
1150 				up->uart_dma.rx_buf_dma_phys, 0, 0);
1151 		omap_set_dma_transfer_params(up->uart_dma.rx_dma_channel,
1152 				OMAP_DMA_DATA_TYPE_S8,
1153 				up->uart_dma.rx_buf_size, 1,
1154 				OMAP_DMA_SYNC_ELEMENT,
1155 				up->uart_dma.uart_dma_rx, 0);
1156 	}
1157 	up->uart_dma.prev_rx_dma_pos = up->uart_dma.rx_buf_dma_phys;
1158 	/* FIXME: Cache maintenance needed here? */
1159 	omap_start_dma(up->uart_dma.rx_dma_channel);
1160 	mod_timer(&up->uart_dma.rx_timer, jiffies +
1161 				usecs_to_jiffies(up->uart_dma.rx_timeout));
1162 	up->uart_dma.rx_dma_used = true;
1163 	return ret;
1164 }
1165 
1166 static void serial_omap_continue_tx(struct uart_omap_port *up)
1167 {
1168 	struct circ_buf *xmit = &up->port.state->xmit;
1169 	unsigned int start = up->uart_dma.tx_buf_dma_phys
1170 			+ (xmit->tail & (UART_XMIT_SIZE - 1));
1171 
1172 	if (uart_circ_empty(xmit))
1173 		return;
1174 
1175 	up->uart_dma.tx_buf_size = uart_circ_chars_pending(xmit);
1176 	/*
1177 	 * It is a circular buffer. See if the buffer has wounded back.
1178 	 * If yes it will have to be transferred in two separate dma
1179 	 * transfers
1180 	 */
1181 	if (start + up->uart_dma.tx_buf_size >=
1182 			up->uart_dma.tx_buf_dma_phys + UART_XMIT_SIZE)
1183 		up->uart_dma.tx_buf_size =
1184 			(up->uart_dma.tx_buf_dma_phys + UART_XMIT_SIZE) - start;
1185 	omap_set_dma_dest_params(up->uart_dma.tx_dma_channel, 0,
1186 				OMAP_DMA_AMODE_CONSTANT,
1187 				up->uart_dma.uart_base, 0, 0);
1188 	omap_set_dma_src_params(up->uart_dma.tx_dma_channel, 0,
1189 				OMAP_DMA_AMODE_POST_INC, start, 0, 0);
1190 	omap_set_dma_transfer_params(up->uart_dma.tx_dma_channel,
1191 				OMAP_DMA_DATA_TYPE_S8,
1192 				up->uart_dma.tx_buf_size, 1,
1193 				OMAP_DMA_SYNC_ELEMENT,
1194 				up->uart_dma.uart_dma_tx, 0);
1195 	/* FIXME: Cache maintenance needed here? */
1196 	omap_start_dma(up->uart_dma.tx_dma_channel);
1197 }
1198 
1199 static void uart_tx_dma_callback(int lch, u16 ch_status, void *data)
1200 {
1201 	struct uart_omap_port *up = (struct uart_omap_port *)data;
1202 	struct circ_buf *xmit = &up->port.state->xmit;
1203 
1204 	xmit->tail = (xmit->tail + up->uart_dma.tx_buf_size) & \
1205 			(UART_XMIT_SIZE - 1);
1206 	up->port.icount.tx += up->uart_dma.tx_buf_size;
1207 
1208 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
1209 		uart_write_wakeup(&up->port);
1210 
1211 	if (uart_circ_empty(xmit)) {
1212 		spin_lock(&(up->uart_dma.tx_lock));
1213 		serial_omap_stop_tx(&up->port);
1214 		up->uart_dma.tx_dma_used = false;
1215 		spin_unlock(&(up->uart_dma.tx_lock));
1216 	} else {
1217 		omap_stop_dma(up->uart_dma.tx_dma_channel);
1218 		serial_omap_continue_tx(up);
1219 	}
1220 	up->port_activity = jiffies;
1221 	return;
1222 }
1223 
1224 static int serial_omap_probe(struct platform_device *pdev)
1225 {
1226 	struct uart_omap_port	*up;
1227 	struct resource		*mem, *irq, *dma_tx, *dma_rx;
1228 	struct omap_uart_port_info *omap_up_info = pdev->dev.platform_data;
1229 	int ret = -ENOSPC;
1230 
1231 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1232 	if (!mem) {
1233 		dev_err(&pdev->dev, "no mem resource?\n");
1234 		return -ENODEV;
1235 	}
1236 
1237 	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
1238 	if (!irq) {
1239 		dev_err(&pdev->dev, "no irq resource?\n");
1240 		return -ENODEV;
1241 	}
1242 
1243 	if (!request_mem_region(mem->start, resource_size(mem),
1244 				pdev->dev.driver->name)) {
1245 		dev_err(&pdev->dev, "memory region already claimed\n");
1246 		return -EBUSY;
1247 	}
1248 
1249 	dma_rx = platform_get_resource_byname(pdev, IORESOURCE_DMA, "rx");
1250 	if (!dma_rx) {
1251 		ret = -EINVAL;
1252 		goto err;
1253 	}
1254 
1255 	dma_tx = platform_get_resource_byname(pdev, IORESOURCE_DMA, "tx");
1256 	if (!dma_tx) {
1257 		ret = -EINVAL;
1258 		goto err;
1259 	}
1260 
1261 	up = kzalloc(sizeof(*up), GFP_KERNEL);
1262 	if (up == NULL) {
1263 		ret = -ENOMEM;
1264 		goto do_release_region;
1265 	}
1266 	sprintf(up->name, "OMAP UART%d", pdev->id);
1267 	up->pdev = pdev;
1268 	up->port.dev = &pdev->dev;
1269 	up->port.type = PORT_OMAP;
1270 	up->port.iotype = UPIO_MEM;
1271 	up->port.irq = irq->start;
1272 
1273 	up->port.regshift = 2;
1274 	up->port.fifosize = 64;
1275 	up->port.ops = &serial_omap_pops;
1276 	up->port.line = pdev->id;
1277 
1278 	up->port.membase = omap_up_info->membase;
1279 	up->port.mapbase = omap_up_info->mapbase;
1280 	up->port.flags = omap_up_info->flags;
1281 	up->port.irqflags = omap_up_info->irqflags;
1282 	up->port.uartclk = omap_up_info->uartclk;
1283 	up->uart_dma.uart_base = mem->start;
1284 
1285 	if (omap_up_info->dma_enabled) {
1286 		up->uart_dma.uart_dma_tx = dma_tx->start;
1287 		up->uart_dma.uart_dma_rx = dma_rx->start;
1288 		up->use_dma = 1;
1289 		up->uart_dma.rx_buf_size = 4096;
1290 		up->uart_dma.rx_timeout = 2;
1291 		spin_lock_init(&(up->uart_dma.tx_lock));
1292 		spin_lock_init(&(up->uart_dma.rx_lock));
1293 		up->uart_dma.tx_dma_channel = OMAP_UART_DMA_CH_FREE;
1294 		up->uart_dma.rx_dma_channel = OMAP_UART_DMA_CH_FREE;
1295 	}
1296 
1297 	ui[pdev->id] = up;
1298 	serial_omap_add_console_port(up);
1299 
1300 	ret = uart_add_one_port(&serial_omap_reg, &up->port);
1301 	if (ret != 0)
1302 		goto do_release_region;
1303 
1304 	platform_set_drvdata(pdev, up);
1305 	return 0;
1306 err:
1307 	dev_err(&pdev->dev, "[UART%d]: failure [%s]: %d\n",
1308 				pdev->id, __func__, ret);
1309 do_release_region:
1310 	release_mem_region(mem->start, resource_size(mem));
1311 	return ret;
1312 }
1313 
1314 static int serial_omap_remove(struct platform_device *dev)
1315 {
1316 	struct uart_omap_port *up = platform_get_drvdata(dev);
1317 
1318 	platform_set_drvdata(dev, NULL);
1319 	if (up) {
1320 		uart_remove_one_port(&serial_omap_reg, &up->port);
1321 		kfree(up);
1322 	}
1323 	return 0;
1324 }
1325 
1326 static struct platform_driver serial_omap_driver = {
1327 	.probe          = serial_omap_probe,
1328 	.remove         = serial_omap_remove,
1329 
1330 	.suspend	= serial_omap_suspend,
1331 	.resume		= serial_omap_resume,
1332 	.driver		= {
1333 		.name	= DRIVER_NAME,
1334 	},
1335 };
1336 
1337 static int __init serial_omap_init(void)
1338 {
1339 	int ret;
1340 
1341 	ret = uart_register_driver(&serial_omap_reg);
1342 	if (ret != 0)
1343 		return ret;
1344 	ret = platform_driver_register(&serial_omap_driver);
1345 	if (ret != 0)
1346 		uart_unregister_driver(&serial_omap_reg);
1347 	return ret;
1348 }
1349 
1350 static void __exit serial_omap_exit(void)
1351 {
1352 	platform_driver_unregister(&serial_omap_driver);
1353 	uart_unregister_driver(&serial_omap_reg);
1354 }
1355 
1356 module_init(serial_omap_init);
1357 module_exit(serial_omap_exit);
1358 
1359 MODULE_DESCRIPTION("OMAP High Speed UART driver");
1360 MODULE_LICENSE("GPL");
1361 MODULE_AUTHOR("Texas Instruments Inc");
1362