xref: /linux/drivers/tty/serial/imx.c (revision 93d90ad708b8da6efc0e487b66111aa9db7f70c7)
1 /*
2  *  Driver for Motorola IMX serial ports
3  *
4  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
5  *
6  *  Author: Sascha Hauer <sascha@saschahauer.de>
7  *  Copyright (C) 2004 Pengutronix
8  *
9  *  Copyright (C) 2009 emlix GmbH
10  *  Author: Fabian Godehardt (added IrDA support for iMX)
11  *
12  * This program is free software; you can redistribute it and/or modify
13  * it under the terms of the GNU General Public License as published by
14  * the Free Software Foundation; either version 2 of the License, or
15  * (at your option) any later version.
16  *
17  * This program is distributed in the hope that it will be useful,
18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
20  * GNU General Public License for more details.
21  *
22  * You should have received a copy of the GNU General Public License
23  * along with this program; if not, write to the Free Software
24  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
25  *
26  * [29-Mar-2005] Mike Lee
27  * Added hardware handshake
28  */
29 
30 #if defined(CONFIG_SERIAL_IMX_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
31 #define SUPPORT_SYSRQ
32 #endif
33 
34 #include <linux/module.h>
35 #include <linux/ioport.h>
36 #include <linux/init.h>
37 #include <linux/console.h>
38 #include <linux/sysrq.h>
39 #include <linux/platform_device.h>
40 #include <linux/tty.h>
41 #include <linux/tty_flip.h>
42 #include <linux/serial_core.h>
43 #include <linux/serial.h>
44 #include <linux/clk.h>
45 #include <linux/delay.h>
46 #include <linux/rational.h>
47 #include <linux/slab.h>
48 #include <linux/of.h>
49 #include <linux/of_device.h>
50 #include <linux/io.h>
51 #include <linux/dma-mapping.h>
52 
53 #include <asm/irq.h>
54 #include <linux/platform_data/serial-imx.h>
55 #include <linux/platform_data/dma-imx.h>
56 
57 /* Register definitions */
58 #define URXD0 0x0  /* Receiver Register */
59 #define URTX0 0x40 /* Transmitter Register */
60 #define UCR1  0x80 /* Control Register 1 */
61 #define UCR2  0x84 /* Control Register 2 */
62 #define UCR3  0x88 /* Control Register 3 */
63 #define UCR4  0x8c /* Control Register 4 */
64 #define UFCR  0x90 /* FIFO Control Register */
65 #define USR1  0x94 /* Status Register 1 */
66 #define USR2  0x98 /* Status Register 2 */
67 #define UESC  0x9c /* Escape Character Register */
68 #define UTIM  0xa0 /* Escape Timer Register */
69 #define UBIR  0xa4 /* BRM Incremental Register */
70 #define UBMR  0xa8 /* BRM Modulator Register */
71 #define UBRC  0xac /* Baud Rate Count Register */
72 #define IMX21_ONEMS 0xb0 /* One Millisecond register */
73 #define IMX1_UTS 0xd0 /* UART Test Register on i.mx1 */
74 #define IMX21_UTS 0xb4 /* UART Test Register on all other i.mx*/
75 
76 /* UART Control Register Bit Fields.*/
77 #define URXD_CHARRDY	(1<<15)
78 #define URXD_ERR	(1<<14)
79 #define URXD_OVRRUN	(1<<13)
80 #define URXD_FRMERR	(1<<12)
81 #define URXD_BRK	(1<<11)
82 #define URXD_PRERR	(1<<10)
83 #define URXD_RX_DATA	(0xFF<<0)
84 #define UCR1_ADEN	(1<<15) /* Auto detect interrupt */
85 #define UCR1_ADBR	(1<<14) /* Auto detect baud rate */
86 #define UCR1_TRDYEN	(1<<13) /* Transmitter ready interrupt enable */
87 #define UCR1_IDEN	(1<<12) /* Idle condition interrupt */
88 #define UCR1_ICD_REG(x) (((x) & 3) << 10) /* idle condition detect */
89 #define UCR1_RRDYEN	(1<<9)	/* Recv ready interrupt enable */
90 #define UCR1_RDMAEN	(1<<8)	/* Recv ready DMA enable */
91 #define UCR1_IREN	(1<<7)	/* Infrared interface enable */
92 #define UCR1_TXMPTYEN	(1<<6)	/* Transimitter empty interrupt enable */
93 #define UCR1_RTSDEN	(1<<5)	/* RTS delta interrupt enable */
94 #define UCR1_SNDBRK	(1<<4)	/* Send break */
95 #define UCR1_TDMAEN	(1<<3)	/* Transmitter ready DMA enable */
96 #define IMX1_UCR1_UARTCLKEN (1<<2) /* UART clock enabled, i.mx1 only */
97 #define UCR1_ATDMAEN    (1<<2)  /* Aging DMA Timer Enable */
98 #define UCR1_DOZE	(1<<1)	/* Doze */
99 #define UCR1_UARTEN	(1<<0)	/* UART enabled */
100 #define UCR2_ESCI	(1<<15)	/* Escape seq interrupt enable */
101 #define UCR2_IRTS	(1<<14)	/* Ignore RTS pin */
102 #define UCR2_CTSC	(1<<13)	/* CTS pin control */
103 #define UCR2_CTS	(1<<12)	/* Clear to send */
104 #define UCR2_ESCEN	(1<<11)	/* Escape enable */
105 #define UCR2_PREN	(1<<8)	/* Parity enable */
106 #define UCR2_PROE	(1<<7)	/* Parity odd/even */
107 #define UCR2_STPB	(1<<6)	/* Stop */
108 #define UCR2_WS		(1<<5)	/* Word size */
109 #define UCR2_RTSEN	(1<<4)	/* Request to send interrupt enable */
110 #define UCR2_ATEN	(1<<3)	/* Aging Timer Enable */
111 #define UCR2_TXEN	(1<<2)	/* Transmitter enabled */
112 #define UCR2_RXEN	(1<<1)	/* Receiver enabled */
113 #define UCR2_SRST	(1<<0)	/* SW reset */
114 #define UCR3_DTREN	(1<<13) /* DTR interrupt enable */
115 #define UCR3_PARERREN	(1<<12) /* Parity enable */
116 #define UCR3_FRAERREN	(1<<11) /* Frame error interrupt enable */
117 #define UCR3_DSR	(1<<10) /* Data set ready */
118 #define UCR3_DCD	(1<<9)	/* Data carrier detect */
119 #define UCR3_RI		(1<<8)	/* Ring indicator */
120 #define UCR3_ADNIMP	(1<<7)	/* Autobaud Detection Not Improved */
121 #define UCR3_RXDSEN	(1<<6)	/* Receive status interrupt enable */
122 #define UCR3_AIRINTEN	(1<<5)	/* Async IR wake interrupt enable */
123 #define UCR3_AWAKEN	(1<<4)	/* Async wake interrupt enable */
124 #define IMX21_UCR3_RXDMUXSEL	(1<<2)	/* RXD Muxed Input Select */
125 #define UCR3_INVT	(1<<1)	/* Inverted Infrared transmission */
126 #define UCR3_BPEN	(1<<0)	/* Preset registers enable */
127 #define UCR4_CTSTL_SHF	10	/* CTS trigger level shift */
128 #define UCR4_CTSTL_MASK	0x3F	/* CTS trigger is 6 bits wide */
129 #define UCR4_INVR	(1<<9)	/* Inverted infrared reception */
130 #define UCR4_ENIRI	(1<<8)	/* Serial infrared interrupt enable */
131 #define UCR4_WKEN	(1<<7)	/* Wake interrupt enable */
132 #define UCR4_REF16	(1<<6)	/* Ref freq 16 MHz */
133 #define UCR4_IDDMAEN    (1<<6)  /* DMA IDLE Condition Detected */
134 #define UCR4_IRSC	(1<<5)	/* IR special case */
135 #define UCR4_TCEN	(1<<3)	/* Transmit complete interrupt enable */
136 #define UCR4_BKEN	(1<<2)	/* Break condition interrupt enable */
137 #define UCR4_OREN	(1<<1)	/* Receiver overrun interrupt enable */
138 #define UCR4_DREN	(1<<0)	/* Recv data ready interrupt enable */
139 #define UFCR_RXTL_SHF	0	/* Receiver trigger level shift */
140 #define UFCR_DCEDTE	(1<<6)	/* DCE/DTE mode select */
141 #define UFCR_RFDIV	(7<<7)	/* Reference freq divider mask */
142 #define UFCR_RFDIV_REG(x)	(((x) < 7 ? 6 - (x) : 6) << 7)
143 #define UFCR_TXTL_SHF	10	/* Transmitter trigger level shift */
144 #define USR1_PARITYERR	(1<<15) /* Parity error interrupt flag */
145 #define USR1_RTSS	(1<<14) /* RTS pin status */
146 #define USR1_TRDY	(1<<13) /* Transmitter ready interrupt/dma flag */
147 #define USR1_RTSD	(1<<12) /* RTS delta */
148 #define USR1_ESCF	(1<<11) /* Escape seq interrupt flag */
149 #define USR1_FRAMERR	(1<<10) /* Frame error interrupt flag */
150 #define USR1_RRDY	(1<<9)	 /* Receiver ready interrupt/dma flag */
151 #define USR1_TIMEOUT	(1<<7)	 /* Receive timeout interrupt status */
152 #define USR1_RXDS	 (1<<6)	 /* Receiver idle interrupt flag */
153 #define USR1_AIRINT	 (1<<5)	 /* Async IR wake interrupt flag */
154 #define USR1_AWAKE	 (1<<4)	 /* Aysnc wake interrupt flag */
155 #define USR2_ADET	 (1<<15) /* Auto baud rate detect complete */
156 #define USR2_TXFE	 (1<<14) /* Transmit buffer FIFO empty */
157 #define USR2_DTRF	 (1<<13) /* DTR edge interrupt flag */
158 #define USR2_IDLE	 (1<<12) /* Idle condition */
159 #define USR2_IRINT	 (1<<8)	 /* Serial infrared interrupt flag */
160 #define USR2_WAKE	 (1<<7)	 /* Wake */
161 #define USR2_RTSF	 (1<<4)	 /* RTS edge interrupt flag */
162 #define USR2_TXDC	 (1<<3)	 /* Transmitter complete */
163 #define USR2_BRCD	 (1<<2)	 /* Break condition */
164 #define USR2_ORE	(1<<1)	 /* Overrun error */
165 #define USR2_RDR	(1<<0)	 /* Recv data ready */
166 #define UTS_FRCPERR	(1<<13) /* Force parity error */
167 #define UTS_LOOP	(1<<12)	 /* Loop tx and rx */
168 #define UTS_TXEMPTY	 (1<<6)	 /* TxFIFO empty */
169 #define UTS_RXEMPTY	 (1<<5)	 /* RxFIFO empty */
170 #define UTS_TXFULL	 (1<<4)	 /* TxFIFO full */
171 #define UTS_RXFULL	 (1<<3)	 /* RxFIFO full */
172 #define UTS_SOFTRST	 (1<<0)	 /* Software reset */
173 
174 /* We've been assigned a range on the "Low-density serial ports" major */
175 #define SERIAL_IMX_MAJOR	207
176 #define MINOR_START		16
177 #define DEV_NAME		"ttymxc"
178 
179 /*
180  * This determines how often we check the modem status signals
181  * for any change.  They generally aren't connected to an IRQ
182  * so we have to poll them.  We also check immediately before
183  * filling the TX fifo incase CTS has been dropped.
184  */
185 #define MCTRL_TIMEOUT	(250*HZ/1000)
186 
187 #define DRIVER_NAME "IMX-uart"
188 
189 #define UART_NR 8
190 
191 /* i.mx21 type uart runs on all i.mx except i.mx1 */
192 enum imx_uart_type {
193 	IMX1_UART,
194 	IMX21_UART,
195 	IMX6Q_UART,
196 };
197 
198 /* device type dependent stuff */
199 struct imx_uart_data {
200 	unsigned uts_reg;
201 	enum imx_uart_type devtype;
202 };
203 
204 struct imx_port {
205 	struct uart_port	port;
206 	struct timer_list	timer;
207 	unsigned int		old_status;
208 	int			txirq, rxirq, rtsirq;
209 	unsigned int		have_rtscts:1;
210 	unsigned int		dte_mode:1;
211 	unsigned int		use_irda:1;
212 	unsigned int		irda_inv_rx:1;
213 	unsigned int		irda_inv_tx:1;
214 	unsigned short		trcv_delay; /* transceiver delay */
215 	struct clk		*clk_ipg;
216 	struct clk		*clk_per;
217 	const struct imx_uart_data *devdata;
218 
219 	/* DMA fields */
220 	unsigned int		dma_is_inited:1;
221 	unsigned int		dma_is_enabled:1;
222 	unsigned int		dma_is_rxing:1;
223 	unsigned int		dma_is_txing:1;
224 	struct dma_chan		*dma_chan_rx, *dma_chan_tx;
225 	struct scatterlist	rx_sgl, tx_sgl[2];
226 	void			*rx_buf;
227 	unsigned int		tx_bytes;
228 	unsigned int		dma_tx_nents;
229 	wait_queue_head_t	dma_wait;
230 };
231 
232 struct imx_port_ucrs {
233 	unsigned int	ucr1;
234 	unsigned int	ucr2;
235 	unsigned int	ucr3;
236 };
237 
238 #ifdef CONFIG_IRDA
239 #define USE_IRDA(sport)	((sport)->use_irda)
240 #else
241 #define USE_IRDA(sport)	(0)
242 #endif
243 
244 static struct imx_uart_data imx_uart_devdata[] = {
245 	[IMX1_UART] = {
246 		.uts_reg = IMX1_UTS,
247 		.devtype = IMX1_UART,
248 	},
249 	[IMX21_UART] = {
250 		.uts_reg = IMX21_UTS,
251 		.devtype = IMX21_UART,
252 	},
253 	[IMX6Q_UART] = {
254 		.uts_reg = IMX21_UTS,
255 		.devtype = IMX6Q_UART,
256 	},
257 };
258 
259 static struct platform_device_id imx_uart_devtype[] = {
260 	{
261 		.name = "imx1-uart",
262 		.driver_data = (kernel_ulong_t) &imx_uart_devdata[IMX1_UART],
263 	}, {
264 		.name = "imx21-uart",
265 		.driver_data = (kernel_ulong_t) &imx_uart_devdata[IMX21_UART],
266 	}, {
267 		.name = "imx6q-uart",
268 		.driver_data = (kernel_ulong_t) &imx_uart_devdata[IMX6Q_UART],
269 	}, {
270 		/* sentinel */
271 	}
272 };
273 MODULE_DEVICE_TABLE(platform, imx_uart_devtype);
274 
275 static struct of_device_id imx_uart_dt_ids[] = {
276 	{ .compatible = "fsl,imx6q-uart", .data = &imx_uart_devdata[IMX6Q_UART], },
277 	{ .compatible = "fsl,imx1-uart", .data = &imx_uart_devdata[IMX1_UART], },
278 	{ .compatible = "fsl,imx21-uart", .data = &imx_uart_devdata[IMX21_UART], },
279 	{ /* sentinel */ }
280 };
281 MODULE_DEVICE_TABLE(of, imx_uart_dt_ids);
282 
283 static inline unsigned uts_reg(struct imx_port *sport)
284 {
285 	return sport->devdata->uts_reg;
286 }
287 
288 static inline int is_imx1_uart(struct imx_port *sport)
289 {
290 	return sport->devdata->devtype == IMX1_UART;
291 }
292 
293 static inline int is_imx21_uart(struct imx_port *sport)
294 {
295 	return sport->devdata->devtype == IMX21_UART;
296 }
297 
298 static inline int is_imx6q_uart(struct imx_port *sport)
299 {
300 	return sport->devdata->devtype == IMX6Q_UART;
301 }
302 /*
303  * Save and restore functions for UCR1, UCR2 and UCR3 registers
304  */
305 #if defined(CONFIG_SERIAL_IMX_CONSOLE)
306 static void imx_port_ucrs_save(struct uart_port *port,
307 			       struct imx_port_ucrs *ucr)
308 {
309 	/* save control registers */
310 	ucr->ucr1 = readl(port->membase + UCR1);
311 	ucr->ucr2 = readl(port->membase + UCR2);
312 	ucr->ucr3 = readl(port->membase + UCR3);
313 }
314 
315 static void imx_port_ucrs_restore(struct uart_port *port,
316 				  struct imx_port_ucrs *ucr)
317 {
318 	/* restore control registers */
319 	writel(ucr->ucr1, port->membase + UCR1);
320 	writel(ucr->ucr2, port->membase + UCR2);
321 	writel(ucr->ucr3, port->membase + UCR3);
322 }
323 #endif
324 
325 /*
326  * Handle any change of modem status signal since we were last called.
327  */
328 static void imx_mctrl_check(struct imx_port *sport)
329 {
330 	unsigned int status, changed;
331 
332 	status = sport->port.ops->get_mctrl(&sport->port);
333 	changed = status ^ sport->old_status;
334 
335 	if (changed == 0)
336 		return;
337 
338 	sport->old_status = status;
339 
340 	if (changed & TIOCM_RI)
341 		sport->port.icount.rng++;
342 	if (changed & TIOCM_DSR)
343 		sport->port.icount.dsr++;
344 	if (changed & TIOCM_CAR)
345 		uart_handle_dcd_change(&sport->port, status & TIOCM_CAR);
346 	if (changed & TIOCM_CTS)
347 		uart_handle_cts_change(&sport->port, status & TIOCM_CTS);
348 
349 	wake_up_interruptible(&sport->port.state->port.delta_msr_wait);
350 }
351 
352 /*
353  * This is our per-port timeout handler, for checking the
354  * modem status signals.
355  */
356 static void imx_timeout(unsigned long data)
357 {
358 	struct imx_port *sport = (struct imx_port *)data;
359 	unsigned long flags;
360 
361 	if (sport->port.state) {
362 		spin_lock_irqsave(&sport->port.lock, flags);
363 		imx_mctrl_check(sport);
364 		spin_unlock_irqrestore(&sport->port.lock, flags);
365 
366 		mod_timer(&sport->timer, jiffies + MCTRL_TIMEOUT);
367 	}
368 }
369 
370 /*
371  * interrupts disabled on entry
372  */
373 static void imx_stop_tx(struct uart_port *port)
374 {
375 	struct imx_port *sport = (struct imx_port *)port;
376 	unsigned long temp;
377 
378 	if (USE_IRDA(sport)) {
379 		/* half duplex - wait for end of transmission */
380 		int n = 256;
381 		while ((--n > 0) &&
382 		      !(readl(sport->port.membase + USR2) & USR2_TXDC)) {
383 			udelay(5);
384 			barrier();
385 		}
386 		/*
387 		 * irda transceiver - wait a bit more to avoid
388 		 * cutoff, hardware dependent
389 		 */
390 		udelay(sport->trcv_delay);
391 
392 		/*
393 		 * half duplex - reactivate receive mode,
394 		 * flush receive pipe echo crap
395 		 */
396 		if (readl(sport->port.membase + USR2) & USR2_TXDC) {
397 			temp = readl(sport->port.membase + UCR1);
398 			temp &= ~(UCR1_TXMPTYEN | UCR1_TRDYEN);
399 			writel(temp, sport->port.membase + UCR1);
400 
401 			temp = readl(sport->port.membase + UCR4);
402 			temp &= ~(UCR4_TCEN);
403 			writel(temp, sport->port.membase + UCR4);
404 
405 			while (readl(sport->port.membase + URXD0) &
406 			       URXD_CHARRDY)
407 				barrier();
408 
409 			temp = readl(sport->port.membase + UCR1);
410 			temp |= UCR1_RRDYEN;
411 			writel(temp, sport->port.membase + UCR1);
412 
413 			temp = readl(sport->port.membase + UCR4);
414 			temp |= UCR4_DREN;
415 			writel(temp, sport->port.membase + UCR4);
416 		}
417 		return;
418 	}
419 
420 	/*
421 	 * We are maybe in the SMP context, so if the DMA TX thread is running
422 	 * on other cpu, we have to wait for it to finish.
423 	 */
424 	if (sport->dma_is_enabled && sport->dma_is_txing)
425 		return;
426 
427 	temp = readl(sport->port.membase + UCR1);
428 	writel(temp & ~UCR1_TXMPTYEN, sport->port.membase + UCR1);
429 }
430 
431 /*
432  * interrupts disabled on entry
433  */
434 static void imx_stop_rx(struct uart_port *port)
435 {
436 	struct imx_port *sport = (struct imx_port *)port;
437 	unsigned long temp;
438 
439 	if (sport->dma_is_enabled && sport->dma_is_rxing) {
440 		if (sport->port.suspended) {
441 			dmaengine_terminate_all(sport->dma_chan_rx);
442 			sport->dma_is_rxing = 0;
443 		} else {
444 			return;
445 		}
446 	}
447 
448 	temp = readl(sport->port.membase + UCR2);
449 	writel(temp & ~UCR2_RXEN, sport->port.membase + UCR2);
450 
451 	/* disable the `Receiver Ready Interrrupt` */
452 	temp = readl(sport->port.membase + UCR1);
453 	writel(temp & ~UCR1_RRDYEN, sport->port.membase + UCR1);
454 }
455 
456 /*
457  * Set the modem control timer to fire immediately.
458  */
459 static void imx_enable_ms(struct uart_port *port)
460 {
461 	struct imx_port *sport = (struct imx_port *)port;
462 
463 	mod_timer(&sport->timer, jiffies);
464 }
465 
466 static inline void imx_transmit_buffer(struct imx_port *sport)
467 {
468 	struct circ_buf *xmit = &sport->port.state->xmit;
469 
470 	if (sport->port.x_char) {
471 		/* Send next char */
472 		writel(sport->port.x_char, sport->port.membase + URTX0);
473 		return;
474 	}
475 
476 	if (uart_circ_empty(xmit) || uart_tx_stopped(&sport->port)) {
477 		imx_stop_tx(&sport->port);
478 		return;
479 	}
480 
481 	while (!uart_circ_empty(xmit) &&
482 	       !(readl(sport->port.membase + uts_reg(sport)) & UTS_TXFULL)) {
483 		/* send xmit->buf[xmit->tail]
484 		 * out the port here */
485 		writel(xmit->buf[xmit->tail], sport->port.membase + URTX0);
486 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
487 		sport->port.icount.tx++;
488 	}
489 
490 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
491 		uart_write_wakeup(&sport->port);
492 
493 	if (uart_circ_empty(xmit))
494 		imx_stop_tx(&sport->port);
495 }
496 
497 static void dma_tx_callback(void *data)
498 {
499 	struct imx_port *sport = data;
500 	struct scatterlist *sgl = &sport->tx_sgl[0];
501 	struct circ_buf *xmit = &sport->port.state->xmit;
502 	unsigned long flags;
503 
504 	dma_unmap_sg(sport->port.dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE);
505 
506 	sport->dma_is_txing = 0;
507 
508 	/* update the stat */
509 	spin_lock_irqsave(&sport->port.lock, flags);
510 	xmit->tail = (xmit->tail + sport->tx_bytes) & (UART_XMIT_SIZE - 1);
511 	sport->port.icount.tx += sport->tx_bytes;
512 	spin_unlock_irqrestore(&sport->port.lock, flags);
513 
514 	dev_dbg(sport->port.dev, "we finish the TX DMA.\n");
515 
516 	uart_write_wakeup(&sport->port);
517 
518 	if (waitqueue_active(&sport->dma_wait)) {
519 		wake_up(&sport->dma_wait);
520 		dev_dbg(sport->port.dev, "exit in %s.\n", __func__);
521 		return;
522 	}
523 }
524 
525 static void imx_dma_tx(struct imx_port *sport)
526 {
527 	struct circ_buf *xmit = &sport->port.state->xmit;
528 	struct scatterlist *sgl = sport->tx_sgl;
529 	struct dma_async_tx_descriptor *desc;
530 	struct dma_chan	*chan = sport->dma_chan_tx;
531 	struct device *dev = sport->port.dev;
532 	enum dma_status status;
533 	int ret;
534 
535 	status = dmaengine_tx_status(chan, (dma_cookie_t)0, NULL);
536 	if (DMA_IN_PROGRESS == status)
537 		return;
538 
539 	sport->tx_bytes = uart_circ_chars_pending(xmit);
540 
541 	if (xmit->tail > xmit->head && xmit->head > 0) {
542 		sport->dma_tx_nents = 2;
543 		sg_init_table(sgl, 2);
544 		sg_set_buf(sgl, xmit->buf + xmit->tail,
545 				UART_XMIT_SIZE - xmit->tail);
546 		sg_set_buf(sgl + 1, xmit->buf, xmit->head);
547 	} else {
548 		sport->dma_tx_nents = 1;
549 		sg_init_one(sgl, xmit->buf + xmit->tail, sport->tx_bytes);
550 	}
551 
552 	ret = dma_map_sg(dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE);
553 	if (ret == 0) {
554 		dev_err(dev, "DMA mapping error for TX.\n");
555 		return;
556 	}
557 	desc = dmaengine_prep_slave_sg(chan, sgl, sport->dma_tx_nents,
558 					DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT);
559 	if (!desc) {
560 		dev_err(dev, "We cannot prepare for the TX slave dma!\n");
561 		return;
562 	}
563 	desc->callback = dma_tx_callback;
564 	desc->callback_param = sport;
565 
566 	dev_dbg(dev, "TX: prepare to send %lu bytes by DMA.\n",
567 			uart_circ_chars_pending(xmit));
568 	/* fire it */
569 	sport->dma_is_txing = 1;
570 	dmaengine_submit(desc);
571 	dma_async_issue_pending(chan);
572 	return;
573 }
574 
575 /*
576  * interrupts disabled on entry
577  */
578 static void imx_start_tx(struct uart_port *port)
579 {
580 	struct imx_port *sport = (struct imx_port *)port;
581 	unsigned long temp;
582 
583 	if (USE_IRDA(sport)) {
584 		/* half duplex in IrDA mode; have to disable receive mode */
585 		temp = readl(sport->port.membase + UCR4);
586 		temp &= ~(UCR4_DREN);
587 		writel(temp, sport->port.membase + UCR4);
588 
589 		temp = readl(sport->port.membase + UCR1);
590 		temp &= ~(UCR1_RRDYEN);
591 		writel(temp, sport->port.membase + UCR1);
592 	}
593 	/* Clear any pending ORE flag before enabling interrupt */
594 	temp = readl(sport->port.membase + USR2);
595 	writel(temp | USR2_ORE, sport->port.membase + USR2);
596 
597 	temp = readl(sport->port.membase + UCR4);
598 	temp |= UCR4_OREN;
599 	writel(temp, sport->port.membase + UCR4);
600 
601 	if (!sport->dma_is_enabled) {
602 		temp = readl(sport->port.membase + UCR1);
603 		writel(temp | UCR1_TXMPTYEN, sport->port.membase + UCR1);
604 	}
605 
606 	if (USE_IRDA(sport)) {
607 		temp = readl(sport->port.membase + UCR1);
608 		temp |= UCR1_TRDYEN;
609 		writel(temp, sport->port.membase + UCR1);
610 
611 		temp = readl(sport->port.membase + UCR4);
612 		temp |= UCR4_TCEN;
613 		writel(temp, sport->port.membase + UCR4);
614 	}
615 
616 	if (sport->dma_is_enabled) {
617 		/* FIXME: port->x_char must be transmitted if != 0 */
618 		if (!uart_circ_empty(&port->state->xmit) &&
619 		    !uart_tx_stopped(port))
620 			imx_dma_tx(sport);
621 		return;
622 	}
623 
624 	if (readl(sport->port.membase + uts_reg(sport)) & UTS_TXEMPTY)
625 		imx_transmit_buffer(sport);
626 }
627 
628 static irqreturn_t imx_rtsint(int irq, void *dev_id)
629 {
630 	struct imx_port *sport = dev_id;
631 	unsigned int val;
632 	unsigned long flags;
633 
634 	spin_lock_irqsave(&sport->port.lock, flags);
635 
636 	writel(USR1_RTSD, sport->port.membase + USR1);
637 	val = readl(sport->port.membase + USR1) & USR1_RTSS;
638 	uart_handle_cts_change(&sport->port, !!val);
639 	wake_up_interruptible(&sport->port.state->port.delta_msr_wait);
640 
641 	spin_unlock_irqrestore(&sport->port.lock, flags);
642 	return IRQ_HANDLED;
643 }
644 
645 static irqreturn_t imx_txint(int irq, void *dev_id)
646 {
647 	struct imx_port *sport = dev_id;
648 	unsigned long flags;
649 
650 	spin_lock_irqsave(&sport->port.lock, flags);
651 	imx_transmit_buffer(sport);
652 	spin_unlock_irqrestore(&sport->port.lock, flags);
653 	return IRQ_HANDLED;
654 }
655 
656 static irqreturn_t imx_rxint(int irq, void *dev_id)
657 {
658 	struct imx_port *sport = dev_id;
659 	unsigned int rx, flg, ignored = 0;
660 	struct tty_port *port = &sport->port.state->port;
661 	unsigned long flags, temp;
662 
663 	spin_lock_irqsave(&sport->port.lock, flags);
664 
665 	while (readl(sport->port.membase + USR2) & USR2_RDR) {
666 		flg = TTY_NORMAL;
667 		sport->port.icount.rx++;
668 
669 		rx = readl(sport->port.membase + URXD0);
670 
671 		temp = readl(sport->port.membase + USR2);
672 		if (temp & USR2_BRCD) {
673 			writel(USR2_BRCD, sport->port.membase + USR2);
674 			if (uart_handle_break(&sport->port))
675 				continue;
676 		}
677 
678 		if (uart_handle_sysrq_char(&sport->port, (unsigned char)rx))
679 			continue;
680 
681 		if (unlikely(rx & URXD_ERR)) {
682 			if (rx & URXD_BRK)
683 				sport->port.icount.brk++;
684 			else if (rx & URXD_PRERR)
685 				sport->port.icount.parity++;
686 			else if (rx & URXD_FRMERR)
687 				sport->port.icount.frame++;
688 			if (rx & URXD_OVRRUN)
689 				sport->port.icount.overrun++;
690 
691 			if (rx & sport->port.ignore_status_mask) {
692 				if (++ignored > 100)
693 					goto out;
694 				continue;
695 			}
696 
697 			rx &= sport->port.read_status_mask;
698 
699 			if (rx & URXD_BRK)
700 				flg = TTY_BREAK;
701 			else if (rx & URXD_PRERR)
702 				flg = TTY_PARITY;
703 			else if (rx & URXD_FRMERR)
704 				flg = TTY_FRAME;
705 			if (rx & URXD_OVRRUN)
706 				flg = TTY_OVERRUN;
707 
708 #ifdef SUPPORT_SYSRQ
709 			sport->port.sysrq = 0;
710 #endif
711 		}
712 
713 		tty_insert_flip_char(port, rx, flg);
714 	}
715 
716 out:
717 	spin_unlock_irqrestore(&sport->port.lock, flags);
718 	tty_flip_buffer_push(port);
719 	return IRQ_HANDLED;
720 }
721 
722 static int start_rx_dma(struct imx_port *sport);
723 /*
724  * If the RXFIFO is filled with some data, and then we
725  * arise a DMA operation to receive them.
726  */
727 static void imx_dma_rxint(struct imx_port *sport)
728 {
729 	unsigned long temp;
730 
731 	temp = readl(sport->port.membase + USR2);
732 	if ((temp & USR2_RDR) && !sport->dma_is_rxing) {
733 		sport->dma_is_rxing = 1;
734 
735 		/* disable the `Recerver Ready Interrrupt` */
736 		temp = readl(sport->port.membase + UCR1);
737 		temp &= ~(UCR1_RRDYEN);
738 		writel(temp, sport->port.membase + UCR1);
739 
740 		/* tell the DMA to receive the data. */
741 		start_rx_dma(sport);
742 	}
743 }
744 
745 static irqreturn_t imx_int(int irq, void *dev_id)
746 {
747 	struct imx_port *sport = dev_id;
748 	unsigned int sts;
749 	unsigned int sts2;
750 
751 	sts = readl(sport->port.membase + USR1);
752 
753 	if (sts & USR1_RRDY) {
754 		if (sport->dma_is_enabled)
755 			imx_dma_rxint(sport);
756 		else
757 			imx_rxint(irq, dev_id);
758 	}
759 
760 	if (sts & USR1_TRDY &&
761 			readl(sport->port.membase + UCR1) & UCR1_TXMPTYEN)
762 		imx_txint(irq, dev_id);
763 
764 	if (sts & USR1_RTSD)
765 		imx_rtsint(irq, dev_id);
766 
767 	if (sts & USR1_AWAKE)
768 		writel(USR1_AWAKE, sport->port.membase + USR1);
769 
770 	sts2 = readl(sport->port.membase + USR2);
771 	if (sts2 & USR2_ORE) {
772 		dev_err(sport->port.dev, "Rx FIFO overrun\n");
773 		sport->port.icount.overrun++;
774 		writel(sts2 | USR2_ORE, sport->port.membase + USR2);
775 	}
776 
777 	return IRQ_HANDLED;
778 }
779 
780 /*
781  * Return TIOCSER_TEMT when transmitter is not busy.
782  */
783 static unsigned int imx_tx_empty(struct uart_port *port)
784 {
785 	struct imx_port *sport = (struct imx_port *)port;
786 	unsigned int ret;
787 
788 	ret = (readl(sport->port.membase + USR2) & USR2_TXDC) ?  TIOCSER_TEMT : 0;
789 
790 	/* If the TX DMA is working, return 0. */
791 	if (sport->dma_is_enabled && sport->dma_is_txing)
792 		ret = 0;
793 
794 	return ret;
795 }
796 
797 /*
798  * We have a modem side uart, so the meanings of RTS and CTS are inverted.
799  */
800 static unsigned int imx_get_mctrl(struct uart_port *port)
801 {
802 	struct imx_port *sport = (struct imx_port *)port;
803 	unsigned int tmp = TIOCM_DSR | TIOCM_CAR;
804 
805 	if (readl(sport->port.membase + USR1) & USR1_RTSS)
806 		tmp |= TIOCM_CTS;
807 
808 	if (readl(sport->port.membase + UCR2) & UCR2_CTS)
809 		tmp |= TIOCM_RTS;
810 
811 	if (readl(sport->port.membase + uts_reg(sport)) & UTS_LOOP)
812 		tmp |= TIOCM_LOOP;
813 
814 	return tmp;
815 }
816 
817 static void imx_set_mctrl(struct uart_port *port, unsigned int mctrl)
818 {
819 	struct imx_port *sport = (struct imx_port *)port;
820 	unsigned long temp;
821 
822 	temp = readl(sport->port.membase + UCR2) & ~(UCR2_CTS | UCR2_CTSC);
823 	if (mctrl & TIOCM_RTS)
824 		temp |= UCR2_CTS | UCR2_CTSC;
825 
826 	writel(temp, sport->port.membase + UCR2);
827 
828 	temp = readl(sport->port.membase + uts_reg(sport)) & ~UTS_LOOP;
829 	if (mctrl & TIOCM_LOOP)
830 		temp |= UTS_LOOP;
831 	writel(temp, sport->port.membase + uts_reg(sport));
832 }
833 
834 /*
835  * Interrupts always disabled.
836  */
837 static void imx_break_ctl(struct uart_port *port, int break_state)
838 {
839 	struct imx_port *sport = (struct imx_port *)port;
840 	unsigned long flags, temp;
841 
842 	spin_lock_irqsave(&sport->port.lock, flags);
843 
844 	temp = readl(sport->port.membase + UCR1) & ~UCR1_SNDBRK;
845 
846 	if (break_state != 0)
847 		temp |= UCR1_SNDBRK;
848 
849 	writel(temp, sport->port.membase + UCR1);
850 
851 	spin_unlock_irqrestore(&sport->port.lock, flags);
852 }
853 
854 #define TXTL 2 /* reset default */
855 #define RXTL 1 /* reset default */
856 
857 static int imx_setup_ufcr(struct imx_port *sport, unsigned int mode)
858 {
859 	unsigned int val;
860 
861 	/* set receiver / transmitter trigger level */
862 	val = readl(sport->port.membase + UFCR) & (UFCR_RFDIV | UFCR_DCEDTE);
863 	val |= TXTL << UFCR_TXTL_SHF | RXTL;
864 	writel(val, sport->port.membase + UFCR);
865 	return 0;
866 }
867 
868 #define RX_BUF_SIZE	(PAGE_SIZE)
869 static void imx_rx_dma_done(struct imx_port *sport)
870 {
871 	unsigned long temp;
872 
873 	/* Enable this interrupt when the RXFIFO is empty. */
874 	temp = readl(sport->port.membase + UCR1);
875 	temp |= UCR1_RRDYEN;
876 	writel(temp, sport->port.membase + UCR1);
877 
878 	sport->dma_is_rxing = 0;
879 
880 	/* Is the shutdown waiting for us? */
881 	if (waitqueue_active(&sport->dma_wait))
882 		wake_up(&sport->dma_wait);
883 }
884 
885 /*
886  * There are three kinds of RX DMA interrupts(such as in the MX6Q):
887  *   [1] the RX DMA buffer is full.
888  *   [2] the Aging timer expires(wait for 8 bytes long)
889  *   [3] the Idle Condition Detect(enabled the UCR4_IDDMAEN).
890  *
891  * The [2] is trigger when a character was been sitting in the FIFO
892  * meanwhile [3] can wait for 32 bytes long when the RX line is
893  * on IDLE state and RxFIFO is empty.
894  */
895 static void dma_rx_callback(void *data)
896 {
897 	struct imx_port *sport = data;
898 	struct dma_chan	*chan = sport->dma_chan_rx;
899 	struct scatterlist *sgl = &sport->rx_sgl;
900 	struct tty_port *port = &sport->port.state->port;
901 	struct dma_tx_state state;
902 	enum dma_status status;
903 	unsigned int count;
904 
905 	/* unmap it first */
906 	dma_unmap_sg(sport->port.dev, sgl, 1, DMA_FROM_DEVICE);
907 
908 	status = dmaengine_tx_status(chan, (dma_cookie_t)0, &state);
909 	count = RX_BUF_SIZE - state.residue;
910 	dev_dbg(sport->port.dev, "We get %d bytes.\n", count);
911 
912 	if (count) {
913 		tty_insert_flip_string(port, sport->rx_buf, count);
914 		tty_flip_buffer_push(port);
915 
916 		start_rx_dma(sport);
917 	} else
918 		imx_rx_dma_done(sport);
919 }
920 
921 static int start_rx_dma(struct imx_port *sport)
922 {
923 	struct scatterlist *sgl = &sport->rx_sgl;
924 	struct dma_chan	*chan = sport->dma_chan_rx;
925 	struct device *dev = sport->port.dev;
926 	struct dma_async_tx_descriptor *desc;
927 	int ret;
928 
929 	sg_init_one(sgl, sport->rx_buf, RX_BUF_SIZE);
930 	ret = dma_map_sg(dev, sgl, 1, DMA_FROM_DEVICE);
931 	if (ret == 0) {
932 		dev_err(dev, "DMA mapping error for RX.\n");
933 		return -EINVAL;
934 	}
935 	desc = dmaengine_prep_slave_sg(chan, sgl, 1, DMA_DEV_TO_MEM,
936 					DMA_PREP_INTERRUPT);
937 	if (!desc) {
938 		dev_err(dev, "We cannot prepare for the RX slave dma!\n");
939 		return -EINVAL;
940 	}
941 	desc->callback = dma_rx_callback;
942 	desc->callback_param = sport;
943 
944 	dev_dbg(dev, "RX: prepare for the DMA.\n");
945 	dmaengine_submit(desc);
946 	dma_async_issue_pending(chan);
947 	return 0;
948 }
949 
950 static void imx_uart_dma_exit(struct imx_port *sport)
951 {
952 	if (sport->dma_chan_rx) {
953 		dma_release_channel(sport->dma_chan_rx);
954 		sport->dma_chan_rx = NULL;
955 
956 		kfree(sport->rx_buf);
957 		sport->rx_buf = NULL;
958 	}
959 
960 	if (sport->dma_chan_tx) {
961 		dma_release_channel(sport->dma_chan_tx);
962 		sport->dma_chan_tx = NULL;
963 	}
964 
965 	sport->dma_is_inited = 0;
966 }
967 
968 static int imx_uart_dma_init(struct imx_port *sport)
969 {
970 	struct dma_slave_config slave_config = {};
971 	struct device *dev = sport->port.dev;
972 	int ret;
973 
974 	/* Prepare for RX : */
975 	sport->dma_chan_rx = dma_request_slave_channel(dev, "rx");
976 	if (!sport->dma_chan_rx) {
977 		dev_dbg(dev, "cannot get the DMA channel.\n");
978 		ret = -EINVAL;
979 		goto err;
980 	}
981 
982 	slave_config.direction = DMA_DEV_TO_MEM;
983 	slave_config.src_addr = sport->port.mapbase + URXD0;
984 	slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
985 	slave_config.src_maxburst = RXTL;
986 	ret = dmaengine_slave_config(sport->dma_chan_rx, &slave_config);
987 	if (ret) {
988 		dev_err(dev, "error in RX dma configuration.\n");
989 		goto err;
990 	}
991 
992 	sport->rx_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
993 	if (!sport->rx_buf) {
994 		ret = -ENOMEM;
995 		goto err;
996 	}
997 
998 	/* Prepare for TX : */
999 	sport->dma_chan_tx = dma_request_slave_channel(dev, "tx");
1000 	if (!sport->dma_chan_tx) {
1001 		dev_err(dev, "cannot get the TX DMA channel!\n");
1002 		ret = -EINVAL;
1003 		goto err;
1004 	}
1005 
1006 	slave_config.direction = DMA_MEM_TO_DEV;
1007 	slave_config.dst_addr = sport->port.mapbase + URTX0;
1008 	slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1009 	slave_config.dst_maxburst = TXTL;
1010 	ret = dmaengine_slave_config(sport->dma_chan_tx, &slave_config);
1011 	if (ret) {
1012 		dev_err(dev, "error in TX dma configuration.");
1013 		goto err;
1014 	}
1015 
1016 	sport->dma_is_inited = 1;
1017 
1018 	return 0;
1019 err:
1020 	imx_uart_dma_exit(sport);
1021 	return ret;
1022 }
1023 
1024 static void imx_enable_dma(struct imx_port *sport)
1025 {
1026 	unsigned long temp;
1027 
1028 	init_waitqueue_head(&sport->dma_wait);
1029 
1030 	/* set UCR1 */
1031 	temp = readl(sport->port.membase + UCR1);
1032 	temp |= UCR1_RDMAEN | UCR1_TDMAEN | UCR1_ATDMAEN |
1033 		/* wait for 32 idle frames for IDDMA interrupt */
1034 		UCR1_ICD_REG(3);
1035 	writel(temp, sport->port.membase + UCR1);
1036 
1037 	/* set UCR4 */
1038 	temp = readl(sport->port.membase + UCR4);
1039 	temp |= UCR4_IDDMAEN;
1040 	writel(temp, sport->port.membase + UCR4);
1041 
1042 	sport->dma_is_enabled = 1;
1043 }
1044 
1045 static void imx_disable_dma(struct imx_port *sport)
1046 {
1047 	unsigned long temp;
1048 
1049 	/* clear UCR1 */
1050 	temp = readl(sport->port.membase + UCR1);
1051 	temp &= ~(UCR1_RDMAEN | UCR1_TDMAEN | UCR1_ATDMAEN);
1052 	writel(temp, sport->port.membase + UCR1);
1053 
1054 	/* clear UCR2 */
1055 	temp = readl(sport->port.membase + UCR2);
1056 	temp &= ~(UCR2_CTSC | UCR2_CTS);
1057 	writel(temp, sport->port.membase + UCR2);
1058 
1059 	/* clear UCR4 */
1060 	temp = readl(sport->port.membase + UCR4);
1061 	temp &= ~UCR4_IDDMAEN;
1062 	writel(temp, sport->port.membase + UCR4);
1063 
1064 	sport->dma_is_enabled = 0;
1065 }
1066 
1067 /* half the RX buffer size */
1068 #define CTSTL 16
1069 
1070 static int imx_startup(struct uart_port *port)
1071 {
1072 	struct imx_port *sport = (struct imx_port *)port;
1073 	int retval, i;
1074 	unsigned long flags, temp;
1075 
1076 	retval = clk_prepare_enable(sport->clk_per);
1077 	if (retval)
1078 		return retval;
1079 	retval = clk_prepare_enable(sport->clk_ipg);
1080 	if (retval) {
1081 		clk_disable_unprepare(sport->clk_per);
1082 		return retval;
1083 	}
1084 
1085 	imx_setup_ufcr(sport, 0);
1086 
1087 	/* disable the DREN bit (Data Ready interrupt enable) before
1088 	 * requesting IRQs
1089 	 */
1090 	temp = readl(sport->port.membase + UCR4);
1091 
1092 	if (USE_IRDA(sport))
1093 		temp |= UCR4_IRSC;
1094 
1095 	/* set the trigger level for CTS */
1096 	temp &= ~(UCR4_CTSTL_MASK << UCR4_CTSTL_SHF);
1097 	temp |= CTSTL << UCR4_CTSTL_SHF;
1098 
1099 	writel(temp & ~UCR4_DREN, sport->port.membase + UCR4);
1100 
1101 	/* Reset fifo's and state machines */
1102 	i = 100;
1103 
1104 	temp = readl(sport->port.membase + UCR2);
1105 	temp &= ~UCR2_SRST;
1106 	writel(temp, sport->port.membase + UCR2);
1107 
1108 	while (!(readl(sport->port.membase + UCR2) & UCR2_SRST) && (--i > 0))
1109 		udelay(1);
1110 
1111 	spin_lock_irqsave(&sport->port.lock, flags);
1112 	/*
1113 	 * Finally, clear and enable interrupts
1114 	 */
1115 	writel(USR1_RTSD, sport->port.membase + USR1);
1116 
1117 	temp = readl(sport->port.membase + UCR1);
1118 	temp |= UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN;
1119 
1120 	if (USE_IRDA(sport)) {
1121 		temp |= UCR1_IREN;
1122 		temp &= ~(UCR1_RTSDEN);
1123 	}
1124 
1125 	writel(temp, sport->port.membase + UCR1);
1126 
1127 	temp = readl(sport->port.membase + UCR2);
1128 	temp |= (UCR2_RXEN | UCR2_TXEN);
1129 	if (!sport->have_rtscts)
1130 		temp |= UCR2_IRTS;
1131 	writel(temp, sport->port.membase + UCR2);
1132 
1133 	if (!is_imx1_uart(sport)) {
1134 		temp = readl(sport->port.membase + UCR3);
1135 		temp |= IMX21_UCR3_RXDMUXSEL | UCR3_ADNIMP;
1136 		writel(temp, sport->port.membase + UCR3);
1137 	}
1138 
1139 	if (USE_IRDA(sport)) {
1140 		temp = readl(sport->port.membase + UCR4);
1141 		if (sport->irda_inv_rx)
1142 			temp |= UCR4_INVR;
1143 		else
1144 			temp &= ~(UCR4_INVR);
1145 		writel(temp | UCR4_DREN, sport->port.membase + UCR4);
1146 
1147 		temp = readl(sport->port.membase + UCR3);
1148 		if (sport->irda_inv_tx)
1149 			temp |= UCR3_INVT;
1150 		else
1151 			temp &= ~(UCR3_INVT);
1152 		writel(temp, sport->port.membase + UCR3);
1153 	}
1154 
1155 	/*
1156 	 * Enable modem status interrupts
1157 	 */
1158 	imx_enable_ms(&sport->port);
1159 	spin_unlock_irqrestore(&sport->port.lock, flags);
1160 
1161 	if (USE_IRDA(sport)) {
1162 		struct imxuart_platform_data *pdata;
1163 		pdata = dev_get_platdata(sport->port.dev);
1164 		sport->irda_inv_rx = pdata->irda_inv_rx;
1165 		sport->irda_inv_tx = pdata->irda_inv_tx;
1166 		sport->trcv_delay = pdata->transceiver_delay;
1167 		if (pdata->irda_enable)
1168 			pdata->irda_enable(1);
1169 	}
1170 
1171 	return 0;
1172 }
1173 
1174 static void imx_shutdown(struct uart_port *port)
1175 {
1176 	struct imx_port *sport = (struct imx_port *)port;
1177 	unsigned long temp;
1178 	unsigned long flags;
1179 
1180 	if (sport->dma_is_enabled) {
1181 		int ret;
1182 
1183 		/* We have to wait for the DMA to finish. */
1184 		ret = wait_event_interruptible(sport->dma_wait,
1185 			!sport->dma_is_rxing && !sport->dma_is_txing);
1186 		if (ret != 0) {
1187 			sport->dma_is_rxing = 0;
1188 			sport->dma_is_txing = 0;
1189 			dmaengine_terminate_all(sport->dma_chan_tx);
1190 			dmaengine_terminate_all(sport->dma_chan_rx);
1191 		}
1192 		imx_stop_tx(port);
1193 		imx_stop_rx(port);
1194 		imx_disable_dma(sport);
1195 		imx_uart_dma_exit(sport);
1196 	}
1197 
1198 	spin_lock_irqsave(&sport->port.lock, flags);
1199 	temp = readl(sport->port.membase + UCR2);
1200 	temp &= ~(UCR2_TXEN);
1201 	writel(temp, sport->port.membase + UCR2);
1202 	spin_unlock_irqrestore(&sport->port.lock, flags);
1203 
1204 	if (USE_IRDA(sport)) {
1205 		struct imxuart_platform_data *pdata;
1206 		pdata = dev_get_platdata(sport->port.dev);
1207 		if (pdata->irda_enable)
1208 			pdata->irda_enable(0);
1209 	}
1210 
1211 	/*
1212 	 * Stop our timer.
1213 	 */
1214 	del_timer_sync(&sport->timer);
1215 
1216 	/*
1217 	 * Disable all interrupts, port and break condition.
1218 	 */
1219 
1220 	spin_lock_irqsave(&sport->port.lock, flags);
1221 	temp = readl(sport->port.membase + UCR1);
1222 	temp &= ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN);
1223 	if (USE_IRDA(sport))
1224 		temp &= ~(UCR1_IREN);
1225 
1226 	writel(temp, sport->port.membase + UCR1);
1227 	spin_unlock_irqrestore(&sport->port.lock, flags);
1228 
1229 	clk_disable_unprepare(sport->clk_per);
1230 	clk_disable_unprepare(sport->clk_ipg);
1231 }
1232 
1233 static void imx_flush_buffer(struct uart_port *port)
1234 {
1235 	struct imx_port *sport = (struct imx_port *)port;
1236 
1237 	if (sport->dma_is_enabled) {
1238 		sport->tx_bytes = 0;
1239 		dmaengine_terminate_all(sport->dma_chan_tx);
1240 	}
1241 }
1242 
1243 static void
1244 imx_set_termios(struct uart_port *port, struct ktermios *termios,
1245 		   struct ktermios *old)
1246 {
1247 	struct imx_port *sport = (struct imx_port *)port;
1248 	unsigned long flags;
1249 	unsigned int ucr2, old_ucr1, old_txrxen, baud, quot;
1250 	unsigned int old_csize = old ? old->c_cflag & CSIZE : CS8;
1251 	unsigned int div, ufcr;
1252 	unsigned long num, denom;
1253 	uint64_t tdiv64;
1254 
1255 	/*
1256 	 * If we don't support modem control lines, don't allow
1257 	 * these to be set.
1258 	 */
1259 	if (0) {
1260 		termios->c_cflag &= ~(HUPCL | CRTSCTS | CMSPAR);
1261 		termios->c_cflag |= CLOCAL;
1262 	}
1263 
1264 	/*
1265 	 * We only support CS7 and CS8.
1266 	 */
1267 	while ((termios->c_cflag & CSIZE) != CS7 &&
1268 	       (termios->c_cflag & CSIZE) != CS8) {
1269 		termios->c_cflag &= ~CSIZE;
1270 		termios->c_cflag |= old_csize;
1271 		old_csize = CS8;
1272 	}
1273 
1274 	if ((termios->c_cflag & CSIZE) == CS8)
1275 		ucr2 = UCR2_WS | UCR2_SRST | UCR2_IRTS;
1276 	else
1277 		ucr2 = UCR2_SRST | UCR2_IRTS;
1278 
1279 	if (termios->c_cflag & CRTSCTS) {
1280 		if (sport->have_rtscts) {
1281 			ucr2 &= ~UCR2_IRTS;
1282 			ucr2 |= UCR2_CTSC;
1283 
1284 			/* Can we enable the DMA support? */
1285 			if (is_imx6q_uart(sport) && !uart_console(port)
1286 				&& !sport->dma_is_inited)
1287 				imx_uart_dma_init(sport);
1288 		} else {
1289 			termios->c_cflag &= ~CRTSCTS;
1290 		}
1291 	}
1292 
1293 	if (termios->c_cflag & CSTOPB)
1294 		ucr2 |= UCR2_STPB;
1295 	if (termios->c_cflag & PARENB) {
1296 		ucr2 |= UCR2_PREN;
1297 		if (termios->c_cflag & PARODD)
1298 			ucr2 |= UCR2_PROE;
1299 	}
1300 
1301 	del_timer_sync(&sport->timer);
1302 
1303 	/*
1304 	 * Ask the core to calculate the divisor for us.
1305 	 */
1306 	baud = uart_get_baud_rate(port, termios, old, 50, port->uartclk / 16);
1307 	quot = uart_get_divisor(port, baud);
1308 
1309 	spin_lock_irqsave(&sport->port.lock, flags);
1310 
1311 	sport->port.read_status_mask = 0;
1312 	if (termios->c_iflag & INPCK)
1313 		sport->port.read_status_mask |= (URXD_FRMERR | URXD_PRERR);
1314 	if (termios->c_iflag & (BRKINT | PARMRK))
1315 		sport->port.read_status_mask |= URXD_BRK;
1316 
1317 	/*
1318 	 * Characters to ignore
1319 	 */
1320 	sport->port.ignore_status_mask = 0;
1321 	if (termios->c_iflag & IGNPAR)
1322 		sport->port.ignore_status_mask |= URXD_PRERR;
1323 	if (termios->c_iflag & IGNBRK) {
1324 		sport->port.ignore_status_mask |= URXD_BRK;
1325 		/*
1326 		 * If we're ignoring parity and break indicators,
1327 		 * ignore overruns too (for real raw support).
1328 		 */
1329 		if (termios->c_iflag & IGNPAR)
1330 			sport->port.ignore_status_mask |= URXD_OVRRUN;
1331 	}
1332 
1333 	/*
1334 	 * Update the per-port timeout.
1335 	 */
1336 	uart_update_timeout(port, termios->c_cflag, baud);
1337 
1338 	/*
1339 	 * disable interrupts and drain transmitter
1340 	 */
1341 	old_ucr1 = readl(sport->port.membase + UCR1);
1342 	writel(old_ucr1 & ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN),
1343 			sport->port.membase + UCR1);
1344 
1345 	while (!(readl(sport->port.membase + USR2) & USR2_TXDC))
1346 		barrier();
1347 
1348 	/* then, disable everything */
1349 	old_txrxen = readl(sport->port.membase + UCR2);
1350 	writel(old_txrxen & ~(UCR2_TXEN | UCR2_RXEN),
1351 			sport->port.membase + UCR2);
1352 	old_txrxen &= (UCR2_TXEN | UCR2_RXEN);
1353 
1354 	if (USE_IRDA(sport)) {
1355 		/*
1356 		 * use maximum available submodule frequency to
1357 		 * avoid missing short pulses due to low sampling rate
1358 		 */
1359 		div = 1;
1360 	} else {
1361 		/* custom-baudrate handling */
1362 		div = sport->port.uartclk / (baud * 16);
1363 		if (baud == 38400 && quot != div)
1364 			baud = sport->port.uartclk / (quot * 16);
1365 
1366 		div = sport->port.uartclk / (baud * 16);
1367 		if (div > 7)
1368 			div = 7;
1369 		if (!div)
1370 			div = 1;
1371 	}
1372 
1373 	rational_best_approximation(16 * div * baud, sport->port.uartclk,
1374 		1 << 16, 1 << 16, &num, &denom);
1375 
1376 	tdiv64 = sport->port.uartclk;
1377 	tdiv64 *= num;
1378 	do_div(tdiv64, denom * 16 * div);
1379 	tty_termios_encode_baud_rate(termios,
1380 				(speed_t)tdiv64, (speed_t)tdiv64);
1381 
1382 	num -= 1;
1383 	denom -= 1;
1384 
1385 	ufcr = readl(sport->port.membase + UFCR);
1386 	ufcr = (ufcr & (~UFCR_RFDIV)) | UFCR_RFDIV_REG(div);
1387 	if (sport->dte_mode)
1388 		ufcr |= UFCR_DCEDTE;
1389 	writel(ufcr, sport->port.membase + UFCR);
1390 
1391 	writel(num, sport->port.membase + UBIR);
1392 	writel(denom, sport->port.membase + UBMR);
1393 
1394 	if (!is_imx1_uart(sport))
1395 		writel(sport->port.uartclk / div / 1000,
1396 				sport->port.membase + IMX21_ONEMS);
1397 
1398 	writel(old_ucr1, sport->port.membase + UCR1);
1399 
1400 	/* set the parity, stop bits and data size */
1401 	writel(ucr2 | old_txrxen, sport->port.membase + UCR2);
1402 
1403 	if (UART_ENABLE_MS(&sport->port, termios->c_cflag))
1404 		imx_enable_ms(&sport->port);
1405 
1406 	if (sport->dma_is_inited && !sport->dma_is_enabled)
1407 		imx_enable_dma(sport);
1408 	spin_unlock_irqrestore(&sport->port.lock, flags);
1409 }
1410 
1411 static const char *imx_type(struct uart_port *port)
1412 {
1413 	struct imx_port *sport = (struct imx_port *)port;
1414 
1415 	return sport->port.type == PORT_IMX ? "IMX" : NULL;
1416 }
1417 
1418 /*
1419  * Configure/autoconfigure the port.
1420  */
1421 static void imx_config_port(struct uart_port *port, int flags)
1422 {
1423 	struct imx_port *sport = (struct imx_port *)port;
1424 
1425 	if (flags & UART_CONFIG_TYPE)
1426 		sport->port.type = PORT_IMX;
1427 }
1428 
1429 /*
1430  * Verify the new serial_struct (for TIOCSSERIAL).
1431  * The only change we allow are to the flags and type, and
1432  * even then only between PORT_IMX and PORT_UNKNOWN
1433  */
1434 static int
1435 imx_verify_port(struct uart_port *port, struct serial_struct *ser)
1436 {
1437 	struct imx_port *sport = (struct imx_port *)port;
1438 	int ret = 0;
1439 
1440 	if (ser->type != PORT_UNKNOWN && ser->type != PORT_IMX)
1441 		ret = -EINVAL;
1442 	if (sport->port.irq != ser->irq)
1443 		ret = -EINVAL;
1444 	if (ser->io_type != UPIO_MEM)
1445 		ret = -EINVAL;
1446 	if (sport->port.uartclk / 16 != ser->baud_base)
1447 		ret = -EINVAL;
1448 	if (sport->port.mapbase != (unsigned long)ser->iomem_base)
1449 		ret = -EINVAL;
1450 	if (sport->port.iobase != ser->port)
1451 		ret = -EINVAL;
1452 	if (ser->hub6 != 0)
1453 		ret = -EINVAL;
1454 	return ret;
1455 }
1456 
1457 #if defined(CONFIG_CONSOLE_POLL)
1458 
1459 static int imx_poll_init(struct uart_port *port)
1460 {
1461 	struct imx_port *sport = (struct imx_port *)port;
1462 	unsigned long flags;
1463 	unsigned long temp;
1464 	int retval;
1465 
1466 	retval = clk_prepare_enable(sport->clk_ipg);
1467 	if (retval)
1468 		return retval;
1469 	retval = clk_prepare_enable(sport->clk_per);
1470 	if (retval)
1471 		clk_disable_unprepare(sport->clk_ipg);
1472 
1473 	imx_setup_ufcr(sport, 0);
1474 
1475 	spin_lock_irqsave(&sport->port.lock, flags);
1476 
1477 	temp = readl(sport->port.membase + UCR1);
1478 	if (is_imx1_uart(sport))
1479 		temp |= IMX1_UCR1_UARTCLKEN;
1480 	temp |= UCR1_UARTEN | UCR1_RRDYEN;
1481 	temp &= ~(UCR1_TXMPTYEN | UCR1_RTSDEN);
1482 	writel(temp, sport->port.membase + UCR1);
1483 
1484 	temp = readl(sport->port.membase + UCR2);
1485 	temp |= UCR2_RXEN;
1486 	writel(temp, sport->port.membase + UCR2);
1487 
1488 	spin_unlock_irqrestore(&sport->port.lock, flags);
1489 
1490 	return 0;
1491 }
1492 
1493 static int imx_poll_get_char(struct uart_port *port)
1494 {
1495 	if (!(readl_relaxed(port->membase + USR2) & USR2_RDR))
1496 		return NO_POLL_CHAR;
1497 
1498 	return readl_relaxed(port->membase + URXD0) & URXD_RX_DATA;
1499 }
1500 
1501 static void imx_poll_put_char(struct uart_port *port, unsigned char c)
1502 {
1503 	unsigned int status;
1504 
1505 	/* drain */
1506 	do {
1507 		status = readl_relaxed(port->membase + USR1);
1508 	} while (~status & USR1_TRDY);
1509 
1510 	/* write */
1511 	writel_relaxed(c, port->membase + URTX0);
1512 
1513 	/* flush */
1514 	do {
1515 		status = readl_relaxed(port->membase + USR2);
1516 	} while (~status & USR2_TXDC);
1517 }
1518 #endif
1519 
1520 static struct uart_ops imx_pops = {
1521 	.tx_empty	= imx_tx_empty,
1522 	.set_mctrl	= imx_set_mctrl,
1523 	.get_mctrl	= imx_get_mctrl,
1524 	.stop_tx	= imx_stop_tx,
1525 	.start_tx	= imx_start_tx,
1526 	.stop_rx	= imx_stop_rx,
1527 	.enable_ms	= imx_enable_ms,
1528 	.break_ctl	= imx_break_ctl,
1529 	.startup	= imx_startup,
1530 	.shutdown	= imx_shutdown,
1531 	.flush_buffer	= imx_flush_buffer,
1532 	.set_termios	= imx_set_termios,
1533 	.type		= imx_type,
1534 	.config_port	= imx_config_port,
1535 	.verify_port	= imx_verify_port,
1536 #if defined(CONFIG_CONSOLE_POLL)
1537 	.poll_init      = imx_poll_init,
1538 	.poll_get_char  = imx_poll_get_char,
1539 	.poll_put_char  = imx_poll_put_char,
1540 #endif
1541 };
1542 
1543 static struct imx_port *imx_ports[UART_NR];
1544 
1545 #ifdef CONFIG_SERIAL_IMX_CONSOLE
1546 static void imx_console_putchar(struct uart_port *port, int ch)
1547 {
1548 	struct imx_port *sport = (struct imx_port *)port;
1549 
1550 	while (readl(sport->port.membase + uts_reg(sport)) & UTS_TXFULL)
1551 		barrier();
1552 
1553 	writel(ch, sport->port.membase + URTX0);
1554 }
1555 
1556 /*
1557  * Interrupts are disabled on entering
1558  */
1559 static void
1560 imx_console_write(struct console *co, const char *s, unsigned int count)
1561 {
1562 	struct imx_port *sport = imx_ports[co->index];
1563 	struct imx_port_ucrs old_ucr;
1564 	unsigned int ucr1;
1565 	unsigned long flags = 0;
1566 	int locked = 1;
1567 	int retval;
1568 
1569 	retval = clk_enable(sport->clk_per);
1570 	if (retval)
1571 		return;
1572 	retval = clk_enable(sport->clk_ipg);
1573 	if (retval) {
1574 		clk_disable(sport->clk_per);
1575 		return;
1576 	}
1577 
1578 	if (sport->port.sysrq)
1579 		locked = 0;
1580 	else if (oops_in_progress)
1581 		locked = spin_trylock_irqsave(&sport->port.lock, flags);
1582 	else
1583 		spin_lock_irqsave(&sport->port.lock, flags);
1584 
1585 	/*
1586 	 *	First, save UCR1/2/3 and then disable interrupts
1587 	 */
1588 	imx_port_ucrs_save(&sport->port, &old_ucr);
1589 	ucr1 = old_ucr.ucr1;
1590 
1591 	if (is_imx1_uart(sport))
1592 		ucr1 |= IMX1_UCR1_UARTCLKEN;
1593 	ucr1 |= UCR1_UARTEN;
1594 	ucr1 &= ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN);
1595 
1596 	writel(ucr1, sport->port.membase + UCR1);
1597 
1598 	writel(old_ucr.ucr2 | UCR2_TXEN, sport->port.membase + UCR2);
1599 
1600 	uart_console_write(&sport->port, s, count, imx_console_putchar);
1601 
1602 	/*
1603 	 *	Finally, wait for transmitter to become empty
1604 	 *	and restore UCR1/2/3
1605 	 */
1606 	while (!(readl(sport->port.membase + USR2) & USR2_TXDC));
1607 
1608 	imx_port_ucrs_restore(&sport->port, &old_ucr);
1609 
1610 	if (locked)
1611 		spin_unlock_irqrestore(&sport->port.lock, flags);
1612 
1613 	clk_disable(sport->clk_ipg);
1614 	clk_disable(sport->clk_per);
1615 }
1616 
1617 /*
1618  * If the port was already initialised (eg, by a boot loader),
1619  * try to determine the current setup.
1620  */
1621 static void __init
1622 imx_console_get_options(struct imx_port *sport, int *baud,
1623 			   int *parity, int *bits)
1624 {
1625 
1626 	if (readl(sport->port.membase + UCR1) & UCR1_UARTEN) {
1627 		/* ok, the port was enabled */
1628 		unsigned int ucr2, ubir, ubmr, uartclk;
1629 		unsigned int baud_raw;
1630 		unsigned int ucfr_rfdiv;
1631 
1632 		ucr2 = readl(sport->port.membase + UCR2);
1633 
1634 		*parity = 'n';
1635 		if (ucr2 & UCR2_PREN) {
1636 			if (ucr2 & UCR2_PROE)
1637 				*parity = 'o';
1638 			else
1639 				*parity = 'e';
1640 		}
1641 
1642 		if (ucr2 & UCR2_WS)
1643 			*bits = 8;
1644 		else
1645 			*bits = 7;
1646 
1647 		ubir = readl(sport->port.membase + UBIR) & 0xffff;
1648 		ubmr = readl(sport->port.membase + UBMR) & 0xffff;
1649 
1650 		ucfr_rfdiv = (readl(sport->port.membase + UFCR) & UFCR_RFDIV) >> 7;
1651 		if (ucfr_rfdiv == 6)
1652 			ucfr_rfdiv = 7;
1653 		else
1654 			ucfr_rfdiv = 6 - ucfr_rfdiv;
1655 
1656 		uartclk = clk_get_rate(sport->clk_per);
1657 		uartclk /= ucfr_rfdiv;
1658 
1659 		{	/*
1660 			 * The next code provides exact computation of
1661 			 *   baud_raw = round(((uartclk/16) * (ubir + 1)) / (ubmr + 1))
1662 			 * without need of float support or long long division,
1663 			 * which would be required to prevent 32bit arithmetic overflow
1664 			 */
1665 			unsigned int mul = ubir + 1;
1666 			unsigned int div = 16 * (ubmr + 1);
1667 			unsigned int rem = uartclk % div;
1668 
1669 			baud_raw = (uartclk / div) * mul;
1670 			baud_raw += (rem * mul + div / 2) / div;
1671 			*baud = (baud_raw + 50) / 100 * 100;
1672 		}
1673 
1674 		if (*baud != baud_raw)
1675 			pr_info("Console IMX rounded baud rate from %d to %d\n",
1676 				baud_raw, *baud);
1677 	}
1678 }
1679 
1680 static int __init
1681 imx_console_setup(struct console *co, char *options)
1682 {
1683 	struct imx_port *sport;
1684 	int baud = 9600;
1685 	int bits = 8;
1686 	int parity = 'n';
1687 	int flow = 'n';
1688 	int retval;
1689 
1690 	/*
1691 	 * Check whether an invalid uart number has been specified, and
1692 	 * if so, search for the first available port that does have
1693 	 * console support.
1694 	 */
1695 	if (co->index == -1 || co->index >= ARRAY_SIZE(imx_ports))
1696 		co->index = 0;
1697 	sport = imx_ports[co->index];
1698 	if (sport == NULL)
1699 		return -ENODEV;
1700 
1701 	/* For setting the registers, we only need to enable the ipg clock. */
1702 	retval = clk_prepare_enable(sport->clk_ipg);
1703 	if (retval)
1704 		goto error_console;
1705 
1706 	if (options)
1707 		uart_parse_options(options, &baud, &parity, &bits, &flow);
1708 	else
1709 		imx_console_get_options(sport, &baud, &parity, &bits);
1710 
1711 	imx_setup_ufcr(sport, 0);
1712 
1713 	retval = uart_set_options(&sport->port, co, baud, parity, bits, flow);
1714 
1715 	clk_disable(sport->clk_ipg);
1716 	if (retval) {
1717 		clk_unprepare(sport->clk_ipg);
1718 		goto error_console;
1719 	}
1720 
1721 	retval = clk_prepare(sport->clk_per);
1722 	if (retval)
1723 		clk_disable_unprepare(sport->clk_ipg);
1724 
1725 error_console:
1726 	return retval;
1727 }
1728 
1729 static struct uart_driver imx_reg;
1730 static struct console imx_console = {
1731 	.name		= DEV_NAME,
1732 	.write		= imx_console_write,
1733 	.device		= uart_console_device,
1734 	.setup		= imx_console_setup,
1735 	.flags		= CON_PRINTBUFFER,
1736 	.index		= -1,
1737 	.data		= &imx_reg,
1738 };
1739 
1740 #define IMX_CONSOLE	&imx_console
1741 #else
1742 #define IMX_CONSOLE	NULL
1743 #endif
1744 
1745 static struct uart_driver imx_reg = {
1746 	.owner          = THIS_MODULE,
1747 	.driver_name    = DRIVER_NAME,
1748 	.dev_name       = DEV_NAME,
1749 	.major          = SERIAL_IMX_MAJOR,
1750 	.minor          = MINOR_START,
1751 	.nr             = ARRAY_SIZE(imx_ports),
1752 	.cons           = IMX_CONSOLE,
1753 };
1754 
1755 static int serial_imx_suspend(struct platform_device *dev, pm_message_t state)
1756 {
1757 	struct imx_port *sport = platform_get_drvdata(dev);
1758 	unsigned int val;
1759 
1760 	/* enable wakeup from i.MX UART */
1761 	val = readl(sport->port.membase + UCR3);
1762 	val |= UCR3_AWAKEN;
1763 	writel(val, sport->port.membase + UCR3);
1764 
1765 	uart_suspend_port(&imx_reg, &sport->port);
1766 
1767 	return 0;
1768 }
1769 
1770 static int serial_imx_resume(struct platform_device *dev)
1771 {
1772 	struct imx_port *sport = platform_get_drvdata(dev);
1773 	unsigned int val;
1774 
1775 	/* disable wakeup from i.MX UART */
1776 	val = readl(sport->port.membase + UCR3);
1777 	val &= ~UCR3_AWAKEN;
1778 	writel(val, sport->port.membase + UCR3);
1779 
1780 	uart_resume_port(&imx_reg, &sport->port);
1781 
1782 	return 0;
1783 }
1784 
1785 #ifdef CONFIG_OF
1786 /*
1787  * This function returns 1 iff pdev isn't a device instatiated by dt, 0 iff it
1788  * could successfully get all information from dt or a negative errno.
1789  */
1790 static int serial_imx_probe_dt(struct imx_port *sport,
1791 		struct platform_device *pdev)
1792 {
1793 	struct device_node *np = pdev->dev.of_node;
1794 	const struct of_device_id *of_id =
1795 			of_match_device(imx_uart_dt_ids, &pdev->dev);
1796 	int ret;
1797 
1798 	if (!np)
1799 		/* no device tree device */
1800 		return 1;
1801 
1802 	ret = of_alias_get_id(np, "serial");
1803 	if (ret < 0) {
1804 		dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
1805 		return ret;
1806 	}
1807 	sport->port.line = ret;
1808 
1809 	if (of_get_property(np, "fsl,uart-has-rtscts", NULL))
1810 		sport->have_rtscts = 1;
1811 
1812 	if (of_get_property(np, "fsl,irda-mode", NULL))
1813 		sport->use_irda = 1;
1814 
1815 	if (of_get_property(np, "fsl,dte-mode", NULL))
1816 		sport->dte_mode = 1;
1817 
1818 	sport->devdata = of_id->data;
1819 
1820 	return 0;
1821 }
1822 #else
1823 static inline int serial_imx_probe_dt(struct imx_port *sport,
1824 		struct platform_device *pdev)
1825 {
1826 	return 1;
1827 }
1828 #endif
1829 
1830 static void serial_imx_probe_pdata(struct imx_port *sport,
1831 		struct platform_device *pdev)
1832 {
1833 	struct imxuart_platform_data *pdata = dev_get_platdata(&pdev->dev);
1834 
1835 	sport->port.line = pdev->id;
1836 	sport->devdata = (struct imx_uart_data	*) pdev->id_entry->driver_data;
1837 
1838 	if (!pdata)
1839 		return;
1840 
1841 	if (pdata->flags & IMXUART_HAVE_RTSCTS)
1842 		sport->have_rtscts = 1;
1843 
1844 	if (pdata->flags & IMXUART_IRDA)
1845 		sport->use_irda = 1;
1846 }
1847 
1848 static int serial_imx_probe(struct platform_device *pdev)
1849 {
1850 	struct imx_port *sport;
1851 	void __iomem *base;
1852 	int ret = 0;
1853 	struct resource *res;
1854 
1855 	sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL);
1856 	if (!sport)
1857 		return -ENOMEM;
1858 
1859 	ret = serial_imx_probe_dt(sport, pdev);
1860 	if (ret > 0)
1861 		serial_imx_probe_pdata(sport, pdev);
1862 	else if (ret < 0)
1863 		return ret;
1864 
1865 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1866 	base = devm_ioremap_resource(&pdev->dev, res);
1867 	if (IS_ERR(base))
1868 		return PTR_ERR(base);
1869 
1870 	sport->port.dev = &pdev->dev;
1871 	sport->port.mapbase = res->start;
1872 	sport->port.membase = base;
1873 	sport->port.type = PORT_IMX,
1874 	sport->port.iotype = UPIO_MEM;
1875 	sport->port.irq = platform_get_irq(pdev, 0);
1876 	sport->rxirq = platform_get_irq(pdev, 0);
1877 	sport->txirq = platform_get_irq(pdev, 1);
1878 	sport->rtsirq = platform_get_irq(pdev, 2);
1879 	sport->port.fifosize = 32;
1880 	sport->port.ops = &imx_pops;
1881 	sport->port.flags = UPF_BOOT_AUTOCONF;
1882 	init_timer(&sport->timer);
1883 	sport->timer.function = imx_timeout;
1884 	sport->timer.data     = (unsigned long)sport;
1885 
1886 	sport->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
1887 	if (IS_ERR(sport->clk_ipg)) {
1888 		ret = PTR_ERR(sport->clk_ipg);
1889 		dev_err(&pdev->dev, "failed to get ipg clk: %d\n", ret);
1890 		return ret;
1891 	}
1892 
1893 	sport->clk_per = devm_clk_get(&pdev->dev, "per");
1894 	if (IS_ERR(sport->clk_per)) {
1895 		ret = PTR_ERR(sport->clk_per);
1896 		dev_err(&pdev->dev, "failed to get per clk: %d\n", ret);
1897 		return ret;
1898 	}
1899 
1900 	sport->port.uartclk = clk_get_rate(sport->clk_per);
1901 
1902 	/*
1903 	 * Allocate the IRQ(s) i.MX1 has three interrupts whereas later
1904 	 * chips only have one interrupt.
1905 	 */
1906 	if (sport->txirq > 0) {
1907 		ret = devm_request_irq(&pdev->dev, sport->rxirq, imx_rxint, 0,
1908 				       dev_name(&pdev->dev), sport);
1909 		if (ret)
1910 			return ret;
1911 
1912 		ret = devm_request_irq(&pdev->dev, sport->txirq, imx_txint, 0,
1913 				       dev_name(&pdev->dev), sport);
1914 		if (ret)
1915 			return ret;
1916 
1917 		/* do not use RTS IRQ on IrDA */
1918 		if (!USE_IRDA(sport)) {
1919 			ret = devm_request_irq(&pdev->dev, sport->rtsirq,
1920 					       imx_rtsint, 0,
1921 					       dev_name(&pdev->dev), sport);
1922 			if (ret)
1923 				return ret;
1924 		}
1925 	} else {
1926 		ret = devm_request_irq(&pdev->dev, sport->port.irq, imx_int, 0,
1927 				       dev_name(&pdev->dev), sport);
1928 		if (ret)
1929 			return ret;
1930 	}
1931 
1932 	imx_ports[sport->port.line] = sport;
1933 
1934 	platform_set_drvdata(pdev, sport);
1935 
1936 	return uart_add_one_port(&imx_reg, &sport->port);
1937 }
1938 
1939 static int serial_imx_remove(struct platform_device *pdev)
1940 {
1941 	struct imx_port *sport = platform_get_drvdata(pdev);
1942 
1943 	return uart_remove_one_port(&imx_reg, &sport->port);
1944 }
1945 
1946 static struct platform_driver serial_imx_driver = {
1947 	.probe		= serial_imx_probe,
1948 	.remove		= serial_imx_remove,
1949 
1950 	.suspend	= serial_imx_suspend,
1951 	.resume		= serial_imx_resume,
1952 	.id_table	= imx_uart_devtype,
1953 	.driver		= {
1954 		.name	= "imx-uart",
1955 		.of_match_table = imx_uart_dt_ids,
1956 	},
1957 };
1958 
1959 static int __init imx_serial_init(void)
1960 {
1961 	int ret = uart_register_driver(&imx_reg);
1962 
1963 	if (ret)
1964 		return ret;
1965 
1966 	ret = platform_driver_register(&serial_imx_driver);
1967 	if (ret != 0)
1968 		uart_unregister_driver(&imx_reg);
1969 
1970 	return ret;
1971 }
1972 
1973 static void __exit imx_serial_exit(void)
1974 {
1975 	platform_driver_unregister(&serial_imx_driver);
1976 	uart_unregister_driver(&imx_reg);
1977 }
1978 
1979 module_init(imx_serial_init);
1980 module_exit(imx_serial_exit);
1981 
1982 MODULE_AUTHOR("Sascha Hauer");
1983 MODULE_DESCRIPTION("IMX generic serial port driver");
1984 MODULE_LICENSE("GPL");
1985 MODULE_ALIAS("platform:imx-uart");
1986