xref: /openbmc/linux/drivers/tty/serial/imx.c (revision 089a49b6)
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 UCR1_ADEN	(1<<15) /* Auto detect interrupt */
84 #define UCR1_ADBR	(1<<14) /* Auto detect baud rate */
85 #define UCR1_TRDYEN	(1<<13) /* Transmitter ready interrupt enable */
86 #define UCR1_IDEN	(1<<12) /* Idle condition interrupt */
87 #define UCR1_ICD_REG(x) (((x) & 3) << 10) /* idle condition detect */
88 #define UCR1_RRDYEN	(1<<9)	/* Recv ready interrupt enable */
89 #define UCR1_RDMAEN	(1<<8)	/* Recv ready DMA enable */
90 #define UCR1_IREN	(1<<7)	/* Infrared interface enable */
91 #define UCR1_TXMPTYEN	(1<<6)	/* Transimitter empty interrupt enable */
92 #define UCR1_RTSDEN	(1<<5)	/* RTS delta interrupt enable */
93 #define UCR1_SNDBRK	(1<<4)	/* Send break */
94 #define UCR1_TDMAEN	(1<<3)	/* Transmitter ready DMA enable */
95 #define IMX1_UCR1_UARTCLKEN (1<<2) /* UART clock enabled, i.mx1 only */
96 #define UCR1_ATDMAEN    (1<<2)  /* Aging DMA Timer Enable */
97 #define UCR1_DOZE	(1<<1)	/* Doze */
98 #define UCR1_UARTEN	(1<<0)	/* UART enabled */
99 #define UCR2_ESCI	(1<<15)	/* Escape seq interrupt enable */
100 #define UCR2_IRTS	(1<<14)	/* Ignore RTS pin */
101 #define UCR2_CTSC	(1<<13)	/* CTS pin control */
102 #define UCR2_CTS	(1<<12)	/* Clear to send */
103 #define UCR2_ESCEN	(1<<11)	/* Escape enable */
104 #define UCR2_PREN	(1<<8)	/* Parity enable */
105 #define UCR2_PROE	(1<<7)	/* Parity odd/even */
106 #define UCR2_STPB	(1<<6)	/* Stop */
107 #define UCR2_WS		(1<<5)	/* Word size */
108 #define UCR2_RTSEN	(1<<4)	/* Request to send interrupt enable */
109 #define UCR2_ATEN	(1<<3)	/* Aging Timer Enable */
110 #define UCR2_TXEN	(1<<2)	/* Transmitter enabled */
111 #define UCR2_RXEN	(1<<1)	/* Receiver enabled */
112 #define UCR2_SRST	(1<<0)	/* SW reset */
113 #define UCR3_DTREN	(1<<13) /* DTR interrupt enable */
114 #define UCR3_PARERREN	(1<<12) /* Parity enable */
115 #define UCR3_FRAERREN	(1<<11) /* Frame error interrupt enable */
116 #define UCR3_DSR	(1<<10) /* Data set ready */
117 #define UCR3_DCD	(1<<9)	/* Data carrier detect */
118 #define UCR3_RI		(1<<8)	/* Ring indicator */
119 #define UCR3_TIMEOUTEN	(1<<7)	/* Timeout interrupt enable */
120 #define UCR3_RXDSEN	(1<<6)	/* Receive status interrupt enable */
121 #define UCR3_AIRINTEN	(1<<5)	/* Async IR wake interrupt enable */
122 #define UCR3_AWAKEN	(1<<4)	/* Async wake interrupt enable */
123 #define IMX21_UCR3_RXDMUXSEL	(1<<2)	/* RXD Muxed Input Select */
124 #define UCR3_INVT	(1<<1)	/* Inverted Infrared transmission */
125 #define UCR3_BPEN	(1<<0)	/* Preset registers enable */
126 #define UCR4_CTSTL_SHF	10	/* CTS trigger level shift */
127 #define UCR4_CTSTL_MASK	0x3F	/* CTS trigger is 6 bits wide */
128 #define UCR4_INVR	(1<<9)	/* Inverted infrared reception */
129 #define UCR4_ENIRI	(1<<8)	/* Serial infrared interrupt enable */
130 #define UCR4_WKEN	(1<<7)	/* Wake interrupt enable */
131 #define UCR4_REF16	(1<<6)	/* Ref freq 16 MHz */
132 #define UCR4_IDDMAEN    (1<<6)  /* DMA IDLE Condition Detected */
133 #define UCR4_IRSC	(1<<5)	/* IR special case */
134 #define UCR4_TCEN	(1<<3)	/* Transmit complete interrupt enable */
135 #define UCR4_BKEN	(1<<2)	/* Break condition interrupt enable */
136 #define UCR4_OREN	(1<<1)	/* Receiver overrun interrupt enable */
137 #define UCR4_DREN	(1<<0)	/* Recv data ready interrupt enable */
138 #define UFCR_RXTL_SHF	0	/* Receiver trigger level shift */
139 #define UFCR_DCEDTE	(1<<6)	/* DCE/DTE mode select */
140 #define UFCR_RFDIV	(7<<7)	/* Reference freq divider mask */
141 #define UFCR_RFDIV_REG(x)	(((x) < 7 ? 6 - (x) : 6) << 7)
142 #define UFCR_TXTL_SHF	10	/* Transmitter trigger level shift */
143 #define USR1_PARITYERR	(1<<15) /* Parity error interrupt flag */
144 #define USR1_RTSS	(1<<14) /* RTS pin status */
145 #define USR1_TRDY	(1<<13) /* Transmitter ready interrupt/dma flag */
146 #define USR1_RTSD	(1<<12) /* RTS delta */
147 #define USR1_ESCF	(1<<11) /* Escape seq interrupt flag */
148 #define USR1_FRAMERR	(1<<10) /* Frame error interrupt flag */
149 #define USR1_RRDY	(1<<9)	 /* Receiver ready interrupt/dma flag */
150 #define USR1_TIMEOUT	(1<<7)	 /* Receive timeout interrupt status */
151 #define USR1_RXDS	 (1<<6)	 /* Receiver idle interrupt flag */
152 #define USR1_AIRINT	 (1<<5)	 /* Async IR wake interrupt flag */
153 #define USR1_AWAKE	 (1<<4)	 /* Aysnc wake interrupt flag */
154 #define USR2_ADET	 (1<<15) /* Auto baud rate detect complete */
155 #define USR2_TXFE	 (1<<14) /* Transmit buffer FIFO empty */
156 #define USR2_DTRF	 (1<<13) /* DTR edge interrupt flag */
157 #define USR2_IDLE	 (1<<12) /* Idle condition */
158 #define USR2_IRINT	 (1<<8)	 /* Serial infrared interrupt flag */
159 #define USR2_WAKE	 (1<<7)	 /* Wake */
160 #define USR2_RTSF	 (1<<4)	 /* RTS edge interrupt flag */
161 #define USR2_TXDC	 (1<<3)	 /* Transmitter complete */
162 #define USR2_BRCD	 (1<<2)	 /* Break condition */
163 #define USR2_ORE	(1<<1)	 /* Overrun error */
164 #define USR2_RDR	(1<<0)	 /* Recv data ready */
165 #define UTS_FRCPERR	(1<<13) /* Force parity error */
166 #define UTS_LOOP	(1<<12)	 /* Loop tx and rx */
167 #define UTS_TXEMPTY	 (1<<6)	 /* TxFIFO empty */
168 #define UTS_RXEMPTY	 (1<<5)	 /* RxFIFO empty */
169 #define UTS_TXFULL	 (1<<4)	 /* TxFIFO full */
170 #define UTS_RXFULL	 (1<<3)	 /* RxFIFO full */
171 #define UTS_SOFTRST	 (1<<0)	 /* Software reset */
172 
173 /* We've been assigned a range on the "Low-density serial ports" major */
174 #define SERIAL_IMX_MAJOR	207
175 #define MINOR_START		16
176 #define DEV_NAME		"ttymxc"
177 
178 /*
179  * This determines how often we check the modem status signals
180  * for any change.  They generally aren't connected to an IRQ
181  * so we have to poll them.  We also check immediately before
182  * filling the TX fifo incase CTS has been dropped.
183  */
184 #define MCTRL_TIMEOUT	(250*HZ/1000)
185 
186 #define DRIVER_NAME "IMX-uart"
187 
188 #define UART_NR 8
189 
190 /* i.mx21 type uart runs on all i.mx except i.mx1 */
191 enum imx_uart_type {
192 	IMX1_UART,
193 	IMX21_UART,
194 	IMX6Q_UART,
195 };
196 
197 /* device type dependent stuff */
198 struct imx_uart_data {
199 	unsigned uts_reg;
200 	enum imx_uart_type devtype;
201 };
202 
203 struct imx_port {
204 	struct uart_port	port;
205 	struct timer_list	timer;
206 	unsigned int		old_status;
207 	int			txirq, rxirq, rtsirq;
208 	unsigned int		have_rtscts:1;
209 	unsigned int		dte_mode:1;
210 	unsigned int		use_irda:1;
211 	unsigned int		irda_inv_rx:1;
212 	unsigned int		irda_inv_tx:1;
213 	unsigned short		trcv_delay; /* transceiver delay */
214 	struct clk		*clk_ipg;
215 	struct clk		*clk_per;
216 	const struct imx_uart_data *devdata;
217 
218 	/* DMA fields */
219 	unsigned int		dma_is_inited:1;
220 	unsigned int		dma_is_enabled:1;
221 	unsigned int		dma_is_rxing:1;
222 	unsigned int		dma_is_txing:1;
223 	struct dma_chan		*dma_chan_rx, *dma_chan_tx;
224 	struct scatterlist	rx_sgl, tx_sgl[2];
225 	void			*rx_buf;
226 	unsigned int		rx_bytes, tx_bytes;
227 	struct work_struct	tsk_dma_rx, tsk_dma_tx;
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_CONSOLE_POLL) || 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 	/*
440 	 * We are maybe in the SMP context, so if the DMA TX thread is running
441 	 * on other cpu, we have to wait for it to finish.
442 	 */
443 	if (sport->dma_is_enabled && sport->dma_is_rxing)
444 		return;
445 
446 	temp = readl(sport->port.membase + UCR2);
447 	writel(temp & ~UCR2_RXEN, sport->port.membase + UCR2);
448 }
449 
450 /*
451  * Set the modem control timer to fire immediately.
452  */
453 static void imx_enable_ms(struct uart_port *port)
454 {
455 	struct imx_port *sport = (struct imx_port *)port;
456 
457 	mod_timer(&sport->timer, jiffies);
458 }
459 
460 static inline void imx_transmit_buffer(struct imx_port *sport)
461 {
462 	struct circ_buf *xmit = &sport->port.state->xmit;
463 
464 	while (!uart_circ_empty(xmit) &&
465 			!(readl(sport->port.membase + uts_reg(sport))
466 				& UTS_TXFULL)) {
467 		/* send xmit->buf[xmit->tail]
468 		 * out the port here */
469 		writel(xmit->buf[xmit->tail], sport->port.membase + URTX0);
470 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
471 		sport->port.icount.tx++;
472 	}
473 
474 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
475 		uart_write_wakeup(&sport->port);
476 
477 	if (uart_circ_empty(xmit))
478 		imx_stop_tx(&sport->port);
479 }
480 
481 static void dma_tx_callback(void *data)
482 {
483 	struct imx_port *sport = data;
484 	struct scatterlist *sgl = &sport->tx_sgl[0];
485 	struct circ_buf *xmit = &sport->port.state->xmit;
486 	unsigned long flags;
487 
488 	dma_unmap_sg(sport->port.dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE);
489 
490 	sport->dma_is_txing = 0;
491 
492 	/* update the stat */
493 	spin_lock_irqsave(&sport->port.lock, flags);
494 	xmit->tail = (xmit->tail + sport->tx_bytes) & (UART_XMIT_SIZE - 1);
495 	sport->port.icount.tx += sport->tx_bytes;
496 	spin_unlock_irqrestore(&sport->port.lock, flags);
497 
498 	dev_dbg(sport->port.dev, "we finish the TX DMA.\n");
499 
500 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
501 		uart_write_wakeup(&sport->port);
502 
503 	if (waitqueue_active(&sport->dma_wait)) {
504 		wake_up(&sport->dma_wait);
505 		dev_dbg(sport->port.dev, "exit in %s.\n", __func__);
506 		return;
507 	}
508 
509 	schedule_work(&sport->tsk_dma_tx);
510 }
511 
512 static void dma_tx_work(struct work_struct *w)
513 {
514 	struct imx_port *sport = container_of(w, struct imx_port, tsk_dma_tx);
515 	struct circ_buf *xmit = &sport->port.state->xmit;
516 	struct scatterlist *sgl = sport->tx_sgl;
517 	struct dma_async_tx_descriptor *desc;
518 	struct dma_chan	*chan = sport->dma_chan_tx;
519 	struct device *dev = sport->port.dev;
520 	enum dma_status status;
521 	unsigned long flags;
522 	int ret;
523 
524 	status = chan->device->device_tx_status(chan, (dma_cookie_t)0, NULL);
525 	if (DMA_IN_PROGRESS == status)
526 		return;
527 
528 	spin_lock_irqsave(&sport->port.lock, flags);
529 	sport->tx_bytes = uart_circ_chars_pending(xmit);
530 	if (sport->tx_bytes == 0) {
531 		spin_unlock_irqrestore(&sport->port.lock, flags);
532 		return;
533 	}
534 
535 	if (xmit->tail > xmit->head) {
536 		sport->dma_tx_nents = 2;
537 		sg_init_table(sgl, 2);
538 		sg_set_buf(sgl, xmit->buf + xmit->tail,
539 				UART_XMIT_SIZE - xmit->tail);
540 		sg_set_buf(sgl + 1, xmit->buf, xmit->head);
541 	} else {
542 		sport->dma_tx_nents = 1;
543 		sg_init_one(sgl, xmit->buf + xmit->tail, sport->tx_bytes);
544 	}
545 	spin_unlock_irqrestore(&sport->port.lock, flags);
546 
547 	ret = dma_map_sg(dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE);
548 	if (ret == 0) {
549 		dev_err(dev, "DMA mapping error for TX.\n");
550 		return;
551 	}
552 	desc = dmaengine_prep_slave_sg(chan, sgl, sport->dma_tx_nents,
553 					DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT);
554 	if (!desc) {
555 		dev_err(dev, "We cannot prepare for the TX slave dma!\n");
556 		return;
557 	}
558 	desc->callback = dma_tx_callback;
559 	desc->callback_param = sport;
560 
561 	dev_dbg(dev, "TX: prepare to send %lu bytes by DMA.\n",
562 			uart_circ_chars_pending(xmit));
563 	/* fire it */
564 	sport->dma_is_txing = 1;
565 	dmaengine_submit(desc);
566 	dma_async_issue_pending(chan);
567 	return;
568 }
569 
570 /*
571  * interrupts disabled on entry
572  */
573 static void imx_start_tx(struct uart_port *port)
574 {
575 	struct imx_port *sport = (struct imx_port *)port;
576 	unsigned long temp;
577 
578 	if (USE_IRDA(sport)) {
579 		/* half duplex in IrDA mode; have to disable receive mode */
580 		temp = readl(sport->port.membase + UCR4);
581 		temp &= ~(UCR4_DREN);
582 		writel(temp, sport->port.membase + UCR4);
583 
584 		temp = readl(sport->port.membase + UCR1);
585 		temp &= ~(UCR1_RRDYEN);
586 		writel(temp, sport->port.membase + UCR1);
587 	}
588 	/* Clear any pending ORE flag before enabling interrupt */
589 	temp = readl(sport->port.membase + USR2);
590 	writel(temp | USR2_ORE, sport->port.membase + USR2);
591 
592 	temp = readl(sport->port.membase + UCR4);
593 	temp |= UCR4_OREN;
594 	writel(temp, sport->port.membase + UCR4);
595 
596 	if (!sport->dma_is_enabled) {
597 		temp = readl(sport->port.membase + UCR1);
598 		writel(temp | UCR1_TXMPTYEN, sport->port.membase + UCR1);
599 	}
600 
601 	if (USE_IRDA(sport)) {
602 		temp = readl(sport->port.membase + UCR1);
603 		temp |= UCR1_TRDYEN;
604 		writel(temp, sport->port.membase + UCR1);
605 
606 		temp = readl(sport->port.membase + UCR4);
607 		temp |= UCR4_TCEN;
608 		writel(temp, sport->port.membase + UCR4);
609 	}
610 
611 	if (sport->dma_is_enabled) {
612 		/*
613 		 * We may in the interrupt context, so arise a work_struct to
614 		 * do the real job.
615 		 */
616 		schedule_work(&sport->tsk_dma_tx);
617 		return;
618 	}
619 
620 	if (readl(sport->port.membase + uts_reg(sport)) & UTS_TXEMPTY)
621 		imx_transmit_buffer(sport);
622 }
623 
624 static irqreturn_t imx_rtsint(int irq, void *dev_id)
625 {
626 	struct imx_port *sport = dev_id;
627 	unsigned int val;
628 	unsigned long flags;
629 
630 	spin_lock_irqsave(&sport->port.lock, flags);
631 
632 	writel(USR1_RTSD, sport->port.membase + USR1);
633 	val = readl(sport->port.membase + USR1) & USR1_RTSS;
634 	uart_handle_cts_change(&sport->port, !!val);
635 	wake_up_interruptible(&sport->port.state->port.delta_msr_wait);
636 
637 	spin_unlock_irqrestore(&sport->port.lock, flags);
638 	return IRQ_HANDLED;
639 }
640 
641 static irqreturn_t imx_txint(int irq, void *dev_id)
642 {
643 	struct imx_port *sport = dev_id;
644 	struct circ_buf *xmit = &sport->port.state->xmit;
645 	unsigned long flags;
646 
647 	spin_lock_irqsave(&sport->port.lock, flags);
648 	if (sport->port.x_char) {
649 		/* Send next char */
650 		writel(sport->port.x_char, sport->port.membase + URTX0);
651 		goto out;
652 	}
653 
654 	if (uart_circ_empty(xmit) || uart_tx_stopped(&sport->port)) {
655 		imx_stop_tx(&sport->port);
656 		goto out;
657 	}
658 
659 	imx_transmit_buffer(sport);
660 
661 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
662 		uart_write_wakeup(&sport->port);
663 
664 out:
665 	spin_unlock_irqrestore(&sport->port.lock, flags);
666 	return IRQ_HANDLED;
667 }
668 
669 static irqreturn_t imx_rxint(int irq, void *dev_id)
670 {
671 	struct imx_port *sport = dev_id;
672 	unsigned int rx, flg, ignored = 0;
673 	struct tty_port *port = &sport->port.state->port;
674 	unsigned long flags, temp;
675 
676 	spin_lock_irqsave(&sport->port.lock, flags);
677 
678 	while (readl(sport->port.membase + USR2) & USR2_RDR) {
679 		flg = TTY_NORMAL;
680 		sport->port.icount.rx++;
681 
682 		rx = readl(sport->port.membase + URXD0);
683 
684 		temp = readl(sport->port.membase + USR2);
685 		if (temp & USR2_BRCD) {
686 			writel(USR2_BRCD, sport->port.membase + USR2);
687 			if (uart_handle_break(&sport->port))
688 				continue;
689 		}
690 
691 		if (uart_handle_sysrq_char(&sport->port, (unsigned char)rx))
692 			continue;
693 
694 		if (unlikely(rx & URXD_ERR)) {
695 			if (rx & URXD_BRK)
696 				sport->port.icount.brk++;
697 			else if (rx & URXD_PRERR)
698 				sport->port.icount.parity++;
699 			else if (rx & URXD_FRMERR)
700 				sport->port.icount.frame++;
701 			if (rx & URXD_OVRRUN)
702 				sport->port.icount.overrun++;
703 
704 			if (rx & sport->port.ignore_status_mask) {
705 				if (++ignored > 100)
706 					goto out;
707 				continue;
708 			}
709 
710 			rx &= sport->port.read_status_mask;
711 
712 			if (rx & URXD_BRK)
713 				flg = TTY_BREAK;
714 			else if (rx & URXD_PRERR)
715 				flg = TTY_PARITY;
716 			else if (rx & URXD_FRMERR)
717 				flg = TTY_FRAME;
718 			if (rx & URXD_OVRRUN)
719 				flg = TTY_OVERRUN;
720 
721 #ifdef SUPPORT_SYSRQ
722 			sport->port.sysrq = 0;
723 #endif
724 		}
725 
726 		tty_insert_flip_char(port, rx, flg);
727 	}
728 
729 out:
730 	spin_unlock_irqrestore(&sport->port.lock, flags);
731 	tty_flip_buffer_push(port);
732 	return IRQ_HANDLED;
733 }
734 
735 /*
736  * If the RXFIFO is filled with some data, and then we
737  * arise a DMA operation to receive them.
738  */
739 static void imx_dma_rxint(struct imx_port *sport)
740 {
741 	unsigned long temp;
742 
743 	temp = readl(sport->port.membase + USR2);
744 	if ((temp & USR2_RDR) && !sport->dma_is_rxing) {
745 		sport->dma_is_rxing = 1;
746 
747 		/* disable the `Recerver Ready Interrrupt` */
748 		temp = readl(sport->port.membase + UCR1);
749 		temp &= ~(UCR1_RRDYEN);
750 		writel(temp, sport->port.membase + UCR1);
751 
752 		/* tell the DMA to receive the data. */
753 		schedule_work(&sport->tsk_dma_rx);
754 	}
755 }
756 
757 static irqreturn_t imx_int(int irq, void *dev_id)
758 {
759 	struct imx_port *sport = dev_id;
760 	unsigned int sts;
761 	unsigned int sts2;
762 
763 	sts = readl(sport->port.membase + USR1);
764 
765 	if (sts & USR1_RRDY) {
766 		if (sport->dma_is_enabled)
767 			imx_dma_rxint(sport);
768 		else
769 			imx_rxint(irq, dev_id);
770 	}
771 
772 	if (sts & USR1_TRDY &&
773 			readl(sport->port.membase + UCR1) & UCR1_TXMPTYEN)
774 		imx_txint(irq, dev_id);
775 
776 	if (sts & USR1_RTSD)
777 		imx_rtsint(irq, dev_id);
778 
779 	if (sts & USR1_AWAKE)
780 		writel(USR1_AWAKE, sport->port.membase + USR1);
781 
782 	sts2 = readl(sport->port.membase + USR2);
783 	if (sts2 & USR2_ORE) {
784 		dev_err(sport->port.dev, "Rx FIFO overrun\n");
785 		sport->port.icount.overrun++;
786 		writel(sts2 | USR2_ORE, sport->port.membase + USR2);
787 	}
788 
789 	return IRQ_HANDLED;
790 }
791 
792 /*
793  * Return TIOCSER_TEMT when transmitter is not busy.
794  */
795 static unsigned int imx_tx_empty(struct uart_port *port)
796 {
797 	struct imx_port *sport = (struct imx_port *)port;
798 
799 	return (readl(sport->port.membase + USR2) & USR2_TXDC) ?  TIOCSER_TEMT : 0;
800 }
801 
802 /*
803  * We have a modem side uart, so the meanings of RTS and CTS are inverted.
804  */
805 static unsigned int imx_get_mctrl(struct uart_port *port)
806 {
807 	struct imx_port *sport = (struct imx_port *)port;
808 	unsigned int tmp = TIOCM_DSR | TIOCM_CAR;
809 
810 	if (readl(sport->port.membase + USR1) & USR1_RTSS)
811 		tmp |= TIOCM_CTS;
812 
813 	if (readl(sport->port.membase + UCR2) & UCR2_CTS)
814 		tmp |= TIOCM_RTS;
815 
816 	return tmp;
817 }
818 
819 static void imx_set_mctrl(struct uart_port *port, unsigned int mctrl)
820 {
821 	struct imx_port *sport = (struct imx_port *)port;
822 	unsigned long temp;
823 
824 	temp = readl(sport->port.membase + UCR2) & ~UCR2_CTS;
825 
826 	if (mctrl & TIOCM_RTS)
827 		if (!sport->dma_is_enabled)
828 			temp |= UCR2_CTS;
829 
830 	writel(temp, sport->port.membase + UCR2);
831 }
832 
833 /*
834  * Interrupts always disabled.
835  */
836 static void imx_break_ctl(struct uart_port *port, int break_state)
837 {
838 	struct imx_port *sport = (struct imx_port *)port;
839 	unsigned long flags, temp;
840 
841 	spin_lock_irqsave(&sport->port.lock, flags);
842 
843 	temp = readl(sport->port.membase + UCR1) & ~UCR1_SNDBRK;
844 
845 	if (break_state != 0)
846 		temp |= UCR1_SNDBRK;
847 
848 	writel(temp, sport->port.membase + UCR1);
849 
850 	spin_unlock_irqrestore(&sport->port.lock, flags);
851 }
852 
853 #define TXTL 2 /* reset default */
854 #define RXTL 1 /* reset default */
855 
856 static int imx_setup_ufcr(struct imx_port *sport, unsigned int mode)
857 {
858 	unsigned int val;
859 
860 	/* set receiver / transmitter trigger level */
861 	val = readl(sport->port.membase + UFCR) & (UFCR_RFDIV | UFCR_DCEDTE);
862 	val |= TXTL << UFCR_TXTL_SHF | RXTL;
863 	writel(val, sport->port.membase + UFCR);
864 	return 0;
865 }
866 
867 #define RX_BUF_SIZE	(PAGE_SIZE)
868 static int start_rx_dma(struct imx_port *sport);
869 static void dma_rx_work(struct work_struct *w)
870 {
871 	struct imx_port *sport = container_of(w, struct imx_port, tsk_dma_rx);
872 	struct tty_port *port = &sport->port.state->port;
873 
874 	if (sport->rx_bytes) {
875 		tty_insert_flip_string(port, sport->rx_buf, sport->rx_bytes);
876 		tty_flip_buffer_push(port);
877 		sport->rx_bytes = 0;
878 	}
879 
880 	if (sport->dma_is_rxing)
881 		start_rx_dma(sport);
882 }
883 
884 static void imx_rx_dma_done(struct imx_port *sport)
885 {
886 	unsigned long temp;
887 
888 	/* Enable this interrupt when the RXFIFO is empty. */
889 	temp = readl(sport->port.membase + UCR1);
890 	temp |= UCR1_RRDYEN;
891 	writel(temp, sport->port.membase + UCR1);
892 
893 	sport->dma_is_rxing = 0;
894 
895 	/* Is the shutdown waiting for us? */
896 	if (waitqueue_active(&sport->dma_wait))
897 		wake_up(&sport->dma_wait);
898 }
899 
900 /*
901  * There are three kinds of RX DMA interrupts(such as in the MX6Q):
902  *   [1] the RX DMA buffer is full.
903  *   [2] the Aging timer expires(wait for 8 bytes long)
904  *   [3] the Idle Condition Detect(enabled the UCR4_IDDMAEN).
905  *
906  * The [2] is trigger when a character was been sitting in the FIFO
907  * meanwhile [3] can wait for 32 bytes long when the RX line is
908  * on IDLE state and RxFIFO is empty.
909  */
910 static void dma_rx_callback(void *data)
911 {
912 	struct imx_port *sport = data;
913 	struct dma_chan	*chan = sport->dma_chan_rx;
914 	struct scatterlist *sgl = &sport->rx_sgl;
915 	struct dma_tx_state state;
916 	enum dma_status status;
917 	unsigned int count;
918 
919 	/* unmap it first */
920 	dma_unmap_sg(sport->port.dev, sgl, 1, DMA_FROM_DEVICE);
921 
922 	status = chan->device->device_tx_status(chan, (dma_cookie_t)0, &state);
923 	count = RX_BUF_SIZE - state.residue;
924 	dev_dbg(sport->port.dev, "We get %d bytes.\n", count);
925 
926 	if (count) {
927 		sport->rx_bytes = count;
928 		schedule_work(&sport->tsk_dma_rx);
929 	} else
930 		imx_rx_dma_done(sport);
931 }
932 
933 static int start_rx_dma(struct imx_port *sport)
934 {
935 	struct scatterlist *sgl = &sport->rx_sgl;
936 	struct dma_chan	*chan = sport->dma_chan_rx;
937 	struct device *dev = sport->port.dev;
938 	struct dma_async_tx_descriptor *desc;
939 	int ret;
940 
941 	sg_init_one(sgl, sport->rx_buf, RX_BUF_SIZE);
942 	ret = dma_map_sg(dev, sgl, 1, DMA_FROM_DEVICE);
943 	if (ret == 0) {
944 		dev_err(dev, "DMA mapping error for RX.\n");
945 		return -EINVAL;
946 	}
947 	desc = dmaengine_prep_slave_sg(chan, sgl, 1, DMA_DEV_TO_MEM,
948 					DMA_PREP_INTERRUPT);
949 	if (!desc) {
950 		dev_err(dev, "We cannot prepare for the RX slave dma!\n");
951 		return -EINVAL;
952 	}
953 	desc->callback = dma_rx_callback;
954 	desc->callback_param = sport;
955 
956 	dev_dbg(dev, "RX: prepare for the DMA.\n");
957 	dmaengine_submit(desc);
958 	dma_async_issue_pending(chan);
959 	return 0;
960 }
961 
962 static void imx_uart_dma_exit(struct imx_port *sport)
963 {
964 	if (sport->dma_chan_rx) {
965 		dma_release_channel(sport->dma_chan_rx);
966 		sport->dma_chan_rx = NULL;
967 
968 		kfree(sport->rx_buf);
969 		sport->rx_buf = NULL;
970 	}
971 
972 	if (sport->dma_chan_tx) {
973 		dma_release_channel(sport->dma_chan_tx);
974 		sport->dma_chan_tx = NULL;
975 	}
976 
977 	sport->dma_is_inited = 0;
978 }
979 
980 static int imx_uart_dma_init(struct imx_port *sport)
981 {
982 	struct dma_slave_config slave_config = {};
983 	struct device *dev = sport->port.dev;
984 	int ret;
985 
986 	/* Prepare for RX : */
987 	sport->dma_chan_rx = dma_request_slave_channel(dev, "rx");
988 	if (!sport->dma_chan_rx) {
989 		dev_dbg(dev, "cannot get the DMA channel.\n");
990 		ret = -EINVAL;
991 		goto err;
992 	}
993 
994 	slave_config.direction = DMA_DEV_TO_MEM;
995 	slave_config.src_addr = sport->port.mapbase + URXD0;
996 	slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
997 	slave_config.src_maxburst = RXTL;
998 	ret = dmaengine_slave_config(sport->dma_chan_rx, &slave_config);
999 	if (ret) {
1000 		dev_err(dev, "error in RX dma configuration.\n");
1001 		goto err;
1002 	}
1003 
1004 	sport->rx_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
1005 	if (!sport->rx_buf) {
1006 		dev_err(dev, "cannot alloc DMA buffer.\n");
1007 		ret = -ENOMEM;
1008 		goto err;
1009 	}
1010 	sport->rx_bytes = 0;
1011 
1012 	/* Prepare for TX : */
1013 	sport->dma_chan_tx = dma_request_slave_channel(dev, "tx");
1014 	if (!sport->dma_chan_tx) {
1015 		dev_err(dev, "cannot get the TX DMA channel!\n");
1016 		ret = -EINVAL;
1017 		goto err;
1018 	}
1019 
1020 	slave_config.direction = DMA_MEM_TO_DEV;
1021 	slave_config.dst_addr = sport->port.mapbase + URTX0;
1022 	slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1023 	slave_config.dst_maxburst = TXTL;
1024 	ret = dmaengine_slave_config(sport->dma_chan_tx, &slave_config);
1025 	if (ret) {
1026 		dev_err(dev, "error in TX dma configuration.");
1027 		goto err;
1028 	}
1029 
1030 	sport->dma_is_inited = 1;
1031 
1032 	return 0;
1033 err:
1034 	imx_uart_dma_exit(sport);
1035 	return ret;
1036 }
1037 
1038 static void imx_enable_dma(struct imx_port *sport)
1039 {
1040 	unsigned long temp;
1041 	struct tty_port *port = &sport->port.state->port;
1042 
1043 	port->low_latency = 1;
1044 	INIT_WORK(&sport->tsk_dma_tx, dma_tx_work);
1045 	INIT_WORK(&sport->tsk_dma_rx, dma_rx_work);
1046 	init_waitqueue_head(&sport->dma_wait);
1047 
1048 	/* set UCR1 */
1049 	temp = readl(sport->port.membase + UCR1);
1050 	temp |= UCR1_RDMAEN | UCR1_TDMAEN | UCR1_ATDMAEN |
1051 		/* wait for 32 idle frames for IDDMA interrupt */
1052 		UCR1_ICD_REG(3);
1053 	writel(temp, sport->port.membase + UCR1);
1054 
1055 	/* set UCR4 */
1056 	temp = readl(sport->port.membase + UCR4);
1057 	temp |= UCR4_IDDMAEN;
1058 	writel(temp, sport->port.membase + UCR4);
1059 
1060 	sport->dma_is_enabled = 1;
1061 }
1062 
1063 static void imx_disable_dma(struct imx_port *sport)
1064 {
1065 	unsigned long temp;
1066 	struct tty_port *port = &sport->port.state->port;
1067 
1068 	/* clear UCR1 */
1069 	temp = readl(sport->port.membase + UCR1);
1070 	temp &= ~(UCR1_RDMAEN | UCR1_TDMAEN | UCR1_ATDMAEN);
1071 	writel(temp, sport->port.membase + UCR1);
1072 
1073 	/* clear UCR2 */
1074 	temp = readl(sport->port.membase + UCR2);
1075 	temp &= ~(UCR2_CTSC | UCR2_CTS);
1076 	writel(temp, sport->port.membase + UCR2);
1077 
1078 	/* clear UCR4 */
1079 	temp = readl(sport->port.membase + UCR4);
1080 	temp &= ~UCR4_IDDMAEN;
1081 	writel(temp, sport->port.membase + UCR4);
1082 
1083 	sport->dma_is_enabled = 0;
1084 	port->low_latency = 0;
1085 }
1086 
1087 /* half the RX buffer size */
1088 #define CTSTL 16
1089 
1090 static int imx_startup(struct uart_port *port)
1091 {
1092 	struct imx_port *sport = (struct imx_port *)port;
1093 	int retval;
1094 	unsigned long flags, temp;
1095 
1096 	retval = clk_prepare_enable(sport->clk_per);
1097 	if (retval)
1098 		goto error_out1;
1099 	retval = clk_prepare_enable(sport->clk_ipg);
1100 	if (retval) {
1101 		clk_disable_unprepare(sport->clk_per);
1102 		goto error_out1;
1103 	}
1104 
1105 	imx_setup_ufcr(sport, 0);
1106 
1107 	/* disable the DREN bit (Data Ready interrupt enable) before
1108 	 * requesting IRQs
1109 	 */
1110 	temp = readl(sport->port.membase + UCR4);
1111 
1112 	if (USE_IRDA(sport))
1113 		temp |= UCR4_IRSC;
1114 
1115 	/* set the trigger level for CTS */
1116 	temp &= ~(UCR4_CTSTL_MASK << UCR4_CTSTL_SHF);
1117 	temp |= CTSTL << UCR4_CTSTL_SHF;
1118 
1119 	writel(temp & ~UCR4_DREN, sport->port.membase + UCR4);
1120 
1121 	if (USE_IRDA(sport)) {
1122 		/* reset fifo's and state machines */
1123 		int i = 100;
1124 		temp = readl(sport->port.membase + UCR2);
1125 		temp &= ~UCR2_SRST;
1126 		writel(temp, sport->port.membase + UCR2);
1127 		while (!(readl(sport->port.membase + UCR2) & UCR2_SRST) &&
1128 		    (--i > 0)) {
1129 			udelay(1);
1130 		}
1131 	}
1132 
1133 	/*
1134 	 * Allocate the IRQ(s) i.MX1 has three interrupts whereas later
1135 	 * chips only have one interrupt.
1136 	 */
1137 	if (sport->txirq > 0) {
1138 		retval = request_irq(sport->rxirq, imx_rxint, 0,
1139 				DRIVER_NAME, sport);
1140 		if (retval)
1141 			goto error_out1;
1142 
1143 		retval = request_irq(sport->txirq, imx_txint, 0,
1144 				DRIVER_NAME, sport);
1145 		if (retval)
1146 			goto error_out2;
1147 
1148 		/* do not use RTS IRQ on IrDA */
1149 		if (!USE_IRDA(sport)) {
1150 			retval = request_irq(sport->rtsirq, imx_rtsint, 0,
1151 					DRIVER_NAME, sport);
1152 			if (retval)
1153 				goto error_out3;
1154 		}
1155 	} else {
1156 		retval = request_irq(sport->port.irq, imx_int, 0,
1157 				DRIVER_NAME, sport);
1158 		if (retval) {
1159 			free_irq(sport->port.irq, sport);
1160 			goto error_out1;
1161 		}
1162 	}
1163 
1164 	spin_lock_irqsave(&sport->port.lock, flags);
1165 	/*
1166 	 * Finally, clear and enable interrupts
1167 	 */
1168 	writel(USR1_RTSD, sport->port.membase + USR1);
1169 
1170 	temp = readl(sport->port.membase + UCR1);
1171 	temp |= UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN;
1172 
1173 	if (USE_IRDA(sport)) {
1174 		temp |= UCR1_IREN;
1175 		temp &= ~(UCR1_RTSDEN);
1176 	}
1177 
1178 	writel(temp, sport->port.membase + UCR1);
1179 
1180 	temp = readl(sport->port.membase + UCR2);
1181 	temp |= (UCR2_RXEN | UCR2_TXEN);
1182 	if (!sport->have_rtscts)
1183 		temp |= UCR2_IRTS;
1184 	writel(temp, sport->port.membase + UCR2);
1185 
1186 	if (USE_IRDA(sport)) {
1187 		/* clear RX-FIFO */
1188 		int i = 64;
1189 		while ((--i > 0) &&
1190 			(readl(sport->port.membase + URXD0) & URXD_CHARRDY)) {
1191 			barrier();
1192 		}
1193 	}
1194 
1195 	if (!is_imx1_uart(sport)) {
1196 		temp = readl(sport->port.membase + UCR3);
1197 		temp |= IMX21_UCR3_RXDMUXSEL;
1198 		writel(temp, sport->port.membase + UCR3);
1199 	}
1200 
1201 	if (USE_IRDA(sport)) {
1202 		temp = readl(sport->port.membase + UCR4);
1203 		if (sport->irda_inv_rx)
1204 			temp |= UCR4_INVR;
1205 		else
1206 			temp &= ~(UCR4_INVR);
1207 		writel(temp | UCR4_DREN, sport->port.membase + UCR4);
1208 
1209 		temp = readl(sport->port.membase + UCR3);
1210 		if (sport->irda_inv_tx)
1211 			temp |= UCR3_INVT;
1212 		else
1213 			temp &= ~(UCR3_INVT);
1214 		writel(temp, sport->port.membase + UCR3);
1215 	}
1216 
1217 	/*
1218 	 * Enable modem status interrupts
1219 	 */
1220 	imx_enable_ms(&sport->port);
1221 	spin_unlock_irqrestore(&sport->port.lock, flags);
1222 
1223 	if (USE_IRDA(sport)) {
1224 		struct imxuart_platform_data *pdata;
1225 		pdata = dev_get_platdata(sport->port.dev);
1226 		sport->irda_inv_rx = pdata->irda_inv_rx;
1227 		sport->irda_inv_tx = pdata->irda_inv_tx;
1228 		sport->trcv_delay = pdata->transceiver_delay;
1229 		if (pdata->irda_enable)
1230 			pdata->irda_enable(1);
1231 	}
1232 
1233 	return 0;
1234 
1235 error_out3:
1236 	if (sport->txirq)
1237 		free_irq(sport->txirq, sport);
1238 error_out2:
1239 	if (sport->rxirq)
1240 		free_irq(sport->rxirq, sport);
1241 error_out1:
1242 	return retval;
1243 }
1244 
1245 static void imx_shutdown(struct uart_port *port)
1246 {
1247 	struct imx_port *sport = (struct imx_port *)port;
1248 	unsigned long temp;
1249 	unsigned long flags;
1250 
1251 	if (sport->dma_is_enabled) {
1252 		/* We have to wait for the DMA to finish. */
1253 		wait_event(sport->dma_wait,
1254 			!sport->dma_is_rxing && !sport->dma_is_txing);
1255 		imx_stop_rx(port);
1256 		imx_disable_dma(sport);
1257 		imx_uart_dma_exit(sport);
1258 	}
1259 
1260 	spin_lock_irqsave(&sport->port.lock, flags);
1261 	temp = readl(sport->port.membase + UCR2);
1262 	temp &= ~(UCR2_TXEN);
1263 	writel(temp, sport->port.membase + UCR2);
1264 	spin_unlock_irqrestore(&sport->port.lock, flags);
1265 
1266 	if (USE_IRDA(sport)) {
1267 		struct imxuart_platform_data *pdata;
1268 		pdata = dev_get_platdata(sport->port.dev);
1269 		if (pdata->irda_enable)
1270 			pdata->irda_enable(0);
1271 	}
1272 
1273 	/*
1274 	 * Stop our timer.
1275 	 */
1276 	del_timer_sync(&sport->timer);
1277 
1278 	/*
1279 	 * Free the interrupts
1280 	 */
1281 	if (sport->txirq > 0) {
1282 		if (!USE_IRDA(sport))
1283 			free_irq(sport->rtsirq, sport);
1284 		free_irq(sport->txirq, sport);
1285 		free_irq(sport->rxirq, sport);
1286 	} else
1287 		free_irq(sport->port.irq, sport);
1288 
1289 	/*
1290 	 * Disable all interrupts, port and break condition.
1291 	 */
1292 
1293 	spin_lock_irqsave(&sport->port.lock, flags);
1294 	temp = readl(sport->port.membase + UCR1);
1295 	temp &= ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN);
1296 	if (USE_IRDA(sport))
1297 		temp &= ~(UCR1_IREN);
1298 
1299 	writel(temp, sport->port.membase + UCR1);
1300 	spin_unlock_irqrestore(&sport->port.lock, flags);
1301 
1302 	clk_disable_unprepare(sport->clk_per);
1303 	clk_disable_unprepare(sport->clk_ipg);
1304 }
1305 
1306 static void
1307 imx_set_termios(struct uart_port *port, struct ktermios *termios,
1308 		   struct ktermios *old)
1309 {
1310 	struct imx_port *sport = (struct imx_port *)port;
1311 	unsigned long flags;
1312 	unsigned int ucr2, old_ucr1, old_txrxen, baud, quot;
1313 	unsigned int old_csize = old ? old->c_cflag & CSIZE : CS8;
1314 	unsigned int div, ufcr;
1315 	unsigned long num, denom;
1316 	uint64_t tdiv64;
1317 
1318 	/*
1319 	 * If we don't support modem control lines, don't allow
1320 	 * these to be set.
1321 	 */
1322 	if (0) {
1323 		termios->c_cflag &= ~(HUPCL | CRTSCTS | CMSPAR);
1324 		termios->c_cflag |= CLOCAL;
1325 	}
1326 
1327 	/*
1328 	 * We only support CS7 and CS8.
1329 	 */
1330 	while ((termios->c_cflag & CSIZE) != CS7 &&
1331 	       (termios->c_cflag & CSIZE) != CS8) {
1332 		termios->c_cflag &= ~CSIZE;
1333 		termios->c_cflag |= old_csize;
1334 		old_csize = CS8;
1335 	}
1336 
1337 	if ((termios->c_cflag & CSIZE) == CS8)
1338 		ucr2 = UCR2_WS | UCR2_SRST | UCR2_IRTS;
1339 	else
1340 		ucr2 = UCR2_SRST | UCR2_IRTS;
1341 
1342 	if (termios->c_cflag & CRTSCTS) {
1343 		if (sport->have_rtscts) {
1344 			ucr2 &= ~UCR2_IRTS;
1345 			ucr2 |= UCR2_CTSC;
1346 
1347 			/* Can we enable the DMA support? */
1348 			if (is_imx6q_uart(sport) && !uart_console(port)
1349 				&& !sport->dma_is_inited)
1350 				imx_uart_dma_init(sport);
1351 		} else {
1352 			termios->c_cflag &= ~CRTSCTS;
1353 		}
1354 	}
1355 
1356 	if (termios->c_cflag & CSTOPB)
1357 		ucr2 |= UCR2_STPB;
1358 	if (termios->c_cflag & PARENB) {
1359 		ucr2 |= UCR2_PREN;
1360 		if (termios->c_cflag & PARODD)
1361 			ucr2 |= UCR2_PROE;
1362 	}
1363 
1364 	del_timer_sync(&sport->timer);
1365 
1366 	/*
1367 	 * Ask the core to calculate the divisor for us.
1368 	 */
1369 	baud = uart_get_baud_rate(port, termios, old, 50, port->uartclk / 16);
1370 	quot = uart_get_divisor(port, baud);
1371 
1372 	spin_lock_irqsave(&sport->port.lock, flags);
1373 
1374 	sport->port.read_status_mask = 0;
1375 	if (termios->c_iflag & INPCK)
1376 		sport->port.read_status_mask |= (URXD_FRMERR | URXD_PRERR);
1377 	if (termios->c_iflag & (BRKINT | PARMRK))
1378 		sport->port.read_status_mask |= URXD_BRK;
1379 
1380 	/*
1381 	 * Characters to ignore
1382 	 */
1383 	sport->port.ignore_status_mask = 0;
1384 	if (termios->c_iflag & IGNPAR)
1385 		sport->port.ignore_status_mask |= URXD_PRERR;
1386 	if (termios->c_iflag & IGNBRK) {
1387 		sport->port.ignore_status_mask |= URXD_BRK;
1388 		/*
1389 		 * If we're ignoring parity and break indicators,
1390 		 * ignore overruns too (for real raw support).
1391 		 */
1392 		if (termios->c_iflag & IGNPAR)
1393 			sport->port.ignore_status_mask |= URXD_OVRRUN;
1394 	}
1395 
1396 	/*
1397 	 * Update the per-port timeout.
1398 	 */
1399 	uart_update_timeout(port, termios->c_cflag, baud);
1400 
1401 	/*
1402 	 * disable interrupts and drain transmitter
1403 	 */
1404 	old_ucr1 = readl(sport->port.membase + UCR1);
1405 	writel(old_ucr1 & ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN),
1406 			sport->port.membase + UCR1);
1407 
1408 	while (!(readl(sport->port.membase + USR2) & USR2_TXDC))
1409 		barrier();
1410 
1411 	/* then, disable everything */
1412 	old_txrxen = readl(sport->port.membase + UCR2);
1413 	writel(old_txrxen & ~(UCR2_TXEN | UCR2_RXEN),
1414 			sport->port.membase + UCR2);
1415 	old_txrxen &= (UCR2_TXEN | UCR2_RXEN);
1416 
1417 	if (USE_IRDA(sport)) {
1418 		/*
1419 		 * use maximum available submodule frequency to
1420 		 * avoid missing short pulses due to low sampling rate
1421 		 */
1422 		div = 1;
1423 	} else {
1424 		/* custom-baudrate handling */
1425 		div = sport->port.uartclk / (baud * 16);
1426 		if (baud == 38400 && quot != div)
1427 			baud = sport->port.uartclk / (quot * 16);
1428 
1429 		div = sport->port.uartclk / (baud * 16);
1430 		if (div > 7)
1431 			div = 7;
1432 		if (!div)
1433 			div = 1;
1434 	}
1435 
1436 	rational_best_approximation(16 * div * baud, sport->port.uartclk,
1437 		1 << 16, 1 << 16, &num, &denom);
1438 
1439 	tdiv64 = sport->port.uartclk;
1440 	tdiv64 *= num;
1441 	do_div(tdiv64, denom * 16 * div);
1442 	tty_termios_encode_baud_rate(termios,
1443 				(speed_t)tdiv64, (speed_t)tdiv64);
1444 
1445 	num -= 1;
1446 	denom -= 1;
1447 
1448 	ufcr = readl(sport->port.membase + UFCR);
1449 	ufcr = (ufcr & (~UFCR_RFDIV)) | UFCR_RFDIV_REG(div);
1450 	if (sport->dte_mode)
1451 		ufcr |= UFCR_DCEDTE;
1452 	writel(ufcr, sport->port.membase + UFCR);
1453 
1454 	writel(num, sport->port.membase + UBIR);
1455 	writel(denom, sport->port.membase + UBMR);
1456 
1457 	if (!is_imx1_uart(sport))
1458 		writel(sport->port.uartclk / div / 1000,
1459 				sport->port.membase + IMX21_ONEMS);
1460 
1461 	writel(old_ucr1, sport->port.membase + UCR1);
1462 
1463 	/* set the parity, stop bits and data size */
1464 	writel(ucr2 | old_txrxen, sport->port.membase + UCR2);
1465 
1466 	if (UART_ENABLE_MS(&sport->port, termios->c_cflag))
1467 		imx_enable_ms(&sport->port);
1468 
1469 	if (sport->dma_is_inited && !sport->dma_is_enabled)
1470 		imx_enable_dma(sport);
1471 	spin_unlock_irqrestore(&sport->port.lock, flags);
1472 }
1473 
1474 static const char *imx_type(struct uart_port *port)
1475 {
1476 	struct imx_port *sport = (struct imx_port *)port;
1477 
1478 	return sport->port.type == PORT_IMX ? "IMX" : NULL;
1479 }
1480 
1481 /*
1482  * Release the memory region(s) being used by 'port'.
1483  */
1484 static void imx_release_port(struct uart_port *port)
1485 {
1486 	struct platform_device *pdev = to_platform_device(port->dev);
1487 	struct resource *mmres;
1488 
1489 	mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1490 	release_mem_region(mmres->start, resource_size(mmres));
1491 }
1492 
1493 /*
1494  * Request the memory region(s) being used by 'port'.
1495  */
1496 static int imx_request_port(struct uart_port *port)
1497 {
1498 	struct platform_device *pdev = to_platform_device(port->dev);
1499 	struct resource *mmres;
1500 	void *ret;
1501 
1502 	mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1503 	if (!mmres)
1504 		return -ENODEV;
1505 
1506 	ret = request_mem_region(mmres->start, resource_size(mmres), "imx-uart");
1507 
1508 	return  ret ? 0 : -EBUSY;
1509 }
1510 
1511 /*
1512  * Configure/autoconfigure the port.
1513  */
1514 static void imx_config_port(struct uart_port *port, int flags)
1515 {
1516 	struct imx_port *sport = (struct imx_port *)port;
1517 
1518 	if (flags & UART_CONFIG_TYPE &&
1519 	    imx_request_port(&sport->port) == 0)
1520 		sport->port.type = PORT_IMX;
1521 }
1522 
1523 /*
1524  * Verify the new serial_struct (for TIOCSSERIAL).
1525  * The only change we allow are to the flags and type, and
1526  * even then only between PORT_IMX and PORT_UNKNOWN
1527  */
1528 static int
1529 imx_verify_port(struct uart_port *port, struct serial_struct *ser)
1530 {
1531 	struct imx_port *sport = (struct imx_port *)port;
1532 	int ret = 0;
1533 
1534 	if (ser->type != PORT_UNKNOWN && ser->type != PORT_IMX)
1535 		ret = -EINVAL;
1536 	if (sport->port.irq != ser->irq)
1537 		ret = -EINVAL;
1538 	if (ser->io_type != UPIO_MEM)
1539 		ret = -EINVAL;
1540 	if (sport->port.uartclk / 16 != ser->baud_base)
1541 		ret = -EINVAL;
1542 	if ((void *)sport->port.mapbase != ser->iomem_base)
1543 		ret = -EINVAL;
1544 	if (sport->port.iobase != ser->port)
1545 		ret = -EINVAL;
1546 	if (ser->hub6 != 0)
1547 		ret = -EINVAL;
1548 	return ret;
1549 }
1550 
1551 #if defined(CONFIG_CONSOLE_POLL)
1552 static int imx_poll_get_char(struct uart_port *port)
1553 {
1554 	struct imx_port_ucrs old_ucr;
1555 	unsigned int status;
1556 	unsigned char c;
1557 
1558 	/* save control registers */
1559 	imx_port_ucrs_save(port, &old_ucr);
1560 
1561 	/* disable interrupts */
1562 	writel(UCR1_UARTEN, port->membase + UCR1);
1563 	writel(old_ucr.ucr2 & ~(UCR2_ATEN | UCR2_RTSEN | UCR2_ESCI),
1564 	       port->membase + UCR2);
1565 	writel(old_ucr.ucr3 & ~(UCR3_DCD | UCR3_RI | UCR3_DTREN),
1566 	       port->membase + UCR3);
1567 
1568 	/* poll */
1569 	do {
1570 		status = readl(port->membase + USR2);
1571 	} while (~status & USR2_RDR);
1572 
1573 	/* read */
1574 	c = readl(port->membase + URXD0);
1575 
1576 	/* restore control registers */
1577 	imx_port_ucrs_restore(port, &old_ucr);
1578 
1579 	return c;
1580 }
1581 
1582 static void imx_poll_put_char(struct uart_port *port, unsigned char c)
1583 {
1584 	struct imx_port_ucrs old_ucr;
1585 	unsigned int status;
1586 
1587 	/* save control registers */
1588 	imx_port_ucrs_save(port, &old_ucr);
1589 
1590 	/* disable interrupts */
1591 	writel(UCR1_UARTEN, port->membase + UCR1);
1592 	writel(old_ucr.ucr2 & ~(UCR2_ATEN | UCR2_RTSEN | UCR2_ESCI),
1593 	       port->membase + UCR2);
1594 	writel(old_ucr.ucr3 & ~(UCR3_DCD | UCR3_RI | UCR3_DTREN),
1595 	       port->membase + UCR3);
1596 
1597 	/* drain */
1598 	do {
1599 		status = readl(port->membase + USR1);
1600 	} while (~status & USR1_TRDY);
1601 
1602 	/* write */
1603 	writel(c, port->membase + URTX0);
1604 
1605 	/* flush */
1606 	do {
1607 		status = readl(port->membase + USR2);
1608 	} while (~status & USR2_TXDC);
1609 
1610 	/* restore control registers */
1611 	imx_port_ucrs_restore(port, &old_ucr);
1612 }
1613 #endif
1614 
1615 static struct uart_ops imx_pops = {
1616 	.tx_empty	= imx_tx_empty,
1617 	.set_mctrl	= imx_set_mctrl,
1618 	.get_mctrl	= imx_get_mctrl,
1619 	.stop_tx	= imx_stop_tx,
1620 	.start_tx	= imx_start_tx,
1621 	.stop_rx	= imx_stop_rx,
1622 	.enable_ms	= imx_enable_ms,
1623 	.break_ctl	= imx_break_ctl,
1624 	.startup	= imx_startup,
1625 	.shutdown	= imx_shutdown,
1626 	.set_termios	= imx_set_termios,
1627 	.type		= imx_type,
1628 	.release_port	= imx_release_port,
1629 	.request_port	= imx_request_port,
1630 	.config_port	= imx_config_port,
1631 	.verify_port	= imx_verify_port,
1632 #if defined(CONFIG_CONSOLE_POLL)
1633 	.poll_get_char  = imx_poll_get_char,
1634 	.poll_put_char  = imx_poll_put_char,
1635 #endif
1636 };
1637 
1638 static struct imx_port *imx_ports[UART_NR];
1639 
1640 #ifdef CONFIG_SERIAL_IMX_CONSOLE
1641 static void imx_console_putchar(struct uart_port *port, int ch)
1642 {
1643 	struct imx_port *sport = (struct imx_port *)port;
1644 
1645 	while (readl(sport->port.membase + uts_reg(sport)) & UTS_TXFULL)
1646 		barrier();
1647 
1648 	writel(ch, sport->port.membase + URTX0);
1649 }
1650 
1651 /*
1652  * Interrupts are disabled on entering
1653  */
1654 static void
1655 imx_console_write(struct console *co, const char *s, unsigned int count)
1656 {
1657 	struct imx_port *sport = imx_ports[co->index];
1658 	struct imx_port_ucrs old_ucr;
1659 	unsigned int ucr1;
1660 	unsigned long flags = 0;
1661 	int locked = 1;
1662 	int retval;
1663 
1664 	retval = clk_enable(sport->clk_per);
1665 	if (retval)
1666 		return;
1667 	retval = clk_enable(sport->clk_ipg);
1668 	if (retval) {
1669 		clk_disable(sport->clk_per);
1670 		return;
1671 	}
1672 
1673 	if (sport->port.sysrq)
1674 		locked = 0;
1675 	else if (oops_in_progress)
1676 		locked = spin_trylock_irqsave(&sport->port.lock, flags);
1677 	else
1678 		spin_lock_irqsave(&sport->port.lock, flags);
1679 
1680 	/*
1681 	 *	First, save UCR1/2/3 and then disable interrupts
1682 	 */
1683 	imx_port_ucrs_save(&sport->port, &old_ucr);
1684 	ucr1 = old_ucr.ucr1;
1685 
1686 	if (is_imx1_uart(sport))
1687 		ucr1 |= IMX1_UCR1_UARTCLKEN;
1688 	ucr1 |= UCR1_UARTEN;
1689 	ucr1 &= ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN);
1690 
1691 	writel(ucr1, sport->port.membase + UCR1);
1692 
1693 	writel(old_ucr.ucr2 | UCR2_TXEN, sport->port.membase + UCR2);
1694 
1695 	uart_console_write(&sport->port, s, count, imx_console_putchar);
1696 
1697 	/*
1698 	 *	Finally, wait for transmitter to become empty
1699 	 *	and restore UCR1/2/3
1700 	 */
1701 	while (!(readl(sport->port.membase + USR2) & USR2_TXDC));
1702 
1703 	imx_port_ucrs_restore(&sport->port, &old_ucr);
1704 
1705 	if (locked)
1706 		spin_unlock_irqrestore(&sport->port.lock, flags);
1707 
1708 	clk_disable(sport->clk_ipg);
1709 	clk_disable(sport->clk_per);
1710 }
1711 
1712 /*
1713  * If the port was already initialised (eg, by a boot loader),
1714  * try to determine the current setup.
1715  */
1716 static void __init
1717 imx_console_get_options(struct imx_port *sport, int *baud,
1718 			   int *parity, int *bits)
1719 {
1720 
1721 	if (readl(sport->port.membase + UCR1) & UCR1_UARTEN) {
1722 		/* ok, the port was enabled */
1723 		unsigned int ucr2, ubir, ubmr, uartclk;
1724 		unsigned int baud_raw;
1725 		unsigned int ucfr_rfdiv;
1726 
1727 		ucr2 = readl(sport->port.membase + UCR2);
1728 
1729 		*parity = 'n';
1730 		if (ucr2 & UCR2_PREN) {
1731 			if (ucr2 & UCR2_PROE)
1732 				*parity = 'o';
1733 			else
1734 				*parity = 'e';
1735 		}
1736 
1737 		if (ucr2 & UCR2_WS)
1738 			*bits = 8;
1739 		else
1740 			*bits = 7;
1741 
1742 		ubir = readl(sport->port.membase + UBIR) & 0xffff;
1743 		ubmr = readl(sport->port.membase + UBMR) & 0xffff;
1744 
1745 		ucfr_rfdiv = (readl(sport->port.membase + UFCR) & UFCR_RFDIV) >> 7;
1746 		if (ucfr_rfdiv == 6)
1747 			ucfr_rfdiv = 7;
1748 		else
1749 			ucfr_rfdiv = 6 - ucfr_rfdiv;
1750 
1751 		uartclk = clk_get_rate(sport->clk_per);
1752 		uartclk /= ucfr_rfdiv;
1753 
1754 		{	/*
1755 			 * The next code provides exact computation of
1756 			 *   baud_raw = round(((uartclk/16) * (ubir + 1)) / (ubmr + 1))
1757 			 * without need of float support or long long division,
1758 			 * which would be required to prevent 32bit arithmetic overflow
1759 			 */
1760 			unsigned int mul = ubir + 1;
1761 			unsigned int div = 16 * (ubmr + 1);
1762 			unsigned int rem = uartclk % div;
1763 
1764 			baud_raw = (uartclk / div) * mul;
1765 			baud_raw += (rem * mul + div / 2) / div;
1766 			*baud = (baud_raw + 50) / 100 * 100;
1767 		}
1768 
1769 		if (*baud != baud_raw)
1770 			pr_info("Console IMX rounded baud rate from %d to %d\n",
1771 				baud_raw, *baud);
1772 	}
1773 }
1774 
1775 static int __init
1776 imx_console_setup(struct console *co, char *options)
1777 {
1778 	struct imx_port *sport;
1779 	int baud = 9600;
1780 	int bits = 8;
1781 	int parity = 'n';
1782 	int flow = 'n';
1783 	int retval;
1784 
1785 	/*
1786 	 * Check whether an invalid uart number has been specified, and
1787 	 * if so, search for the first available port that does have
1788 	 * console support.
1789 	 */
1790 	if (co->index == -1 || co->index >= ARRAY_SIZE(imx_ports))
1791 		co->index = 0;
1792 	sport = imx_ports[co->index];
1793 	if (sport == NULL)
1794 		return -ENODEV;
1795 
1796 	/* For setting the registers, we only need to enable the ipg clock. */
1797 	retval = clk_prepare_enable(sport->clk_ipg);
1798 	if (retval)
1799 		goto error_console;
1800 
1801 	if (options)
1802 		uart_parse_options(options, &baud, &parity, &bits, &flow);
1803 	else
1804 		imx_console_get_options(sport, &baud, &parity, &bits);
1805 
1806 	imx_setup_ufcr(sport, 0);
1807 
1808 	retval = uart_set_options(&sport->port, co, baud, parity, bits, flow);
1809 
1810 	clk_disable(sport->clk_ipg);
1811 	if (retval) {
1812 		clk_unprepare(sport->clk_ipg);
1813 		goto error_console;
1814 	}
1815 
1816 	retval = clk_prepare(sport->clk_per);
1817 	if (retval)
1818 		clk_disable_unprepare(sport->clk_ipg);
1819 
1820 error_console:
1821 	return retval;
1822 }
1823 
1824 static struct uart_driver imx_reg;
1825 static struct console imx_console = {
1826 	.name		= DEV_NAME,
1827 	.write		= imx_console_write,
1828 	.device		= uart_console_device,
1829 	.setup		= imx_console_setup,
1830 	.flags		= CON_PRINTBUFFER,
1831 	.index		= -1,
1832 	.data		= &imx_reg,
1833 };
1834 
1835 #define IMX_CONSOLE	&imx_console
1836 #else
1837 #define IMX_CONSOLE	NULL
1838 #endif
1839 
1840 static struct uart_driver imx_reg = {
1841 	.owner          = THIS_MODULE,
1842 	.driver_name    = DRIVER_NAME,
1843 	.dev_name       = DEV_NAME,
1844 	.major          = SERIAL_IMX_MAJOR,
1845 	.minor          = MINOR_START,
1846 	.nr             = ARRAY_SIZE(imx_ports),
1847 	.cons           = IMX_CONSOLE,
1848 };
1849 
1850 static int serial_imx_suspend(struct platform_device *dev, pm_message_t state)
1851 {
1852 	struct imx_port *sport = platform_get_drvdata(dev);
1853 	unsigned int val;
1854 
1855 	/* enable wakeup from i.MX UART */
1856 	val = readl(sport->port.membase + UCR3);
1857 	val |= UCR3_AWAKEN;
1858 	writel(val, sport->port.membase + UCR3);
1859 
1860 	uart_suspend_port(&imx_reg, &sport->port);
1861 
1862 	return 0;
1863 }
1864 
1865 static int serial_imx_resume(struct platform_device *dev)
1866 {
1867 	struct imx_port *sport = platform_get_drvdata(dev);
1868 	unsigned int val;
1869 
1870 	/* disable wakeup from i.MX UART */
1871 	val = readl(sport->port.membase + UCR3);
1872 	val &= ~UCR3_AWAKEN;
1873 	writel(val, sport->port.membase + UCR3);
1874 
1875 	uart_resume_port(&imx_reg, &sport->port);
1876 
1877 	return 0;
1878 }
1879 
1880 #ifdef CONFIG_OF
1881 /*
1882  * This function returns 1 iff pdev isn't a device instatiated by dt, 0 iff it
1883  * could successfully get all information from dt or a negative errno.
1884  */
1885 static int serial_imx_probe_dt(struct imx_port *sport,
1886 		struct platform_device *pdev)
1887 {
1888 	struct device_node *np = pdev->dev.of_node;
1889 	const struct of_device_id *of_id =
1890 			of_match_device(imx_uart_dt_ids, &pdev->dev);
1891 	int ret;
1892 
1893 	if (!np)
1894 		/* no device tree device */
1895 		return 1;
1896 
1897 	ret = of_alias_get_id(np, "serial");
1898 	if (ret < 0) {
1899 		dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
1900 		return ret;
1901 	}
1902 	sport->port.line = ret;
1903 
1904 	if (of_get_property(np, "fsl,uart-has-rtscts", NULL))
1905 		sport->have_rtscts = 1;
1906 
1907 	if (of_get_property(np, "fsl,irda-mode", NULL))
1908 		sport->use_irda = 1;
1909 
1910 	if (of_get_property(np, "fsl,dte-mode", NULL))
1911 		sport->dte_mode = 1;
1912 
1913 	sport->devdata = of_id->data;
1914 
1915 	if (of_device_is_stdout_path(np))
1916 		add_preferred_console(imx_reg.cons->name, sport->port.line, 0);
1917 
1918 	return 0;
1919 }
1920 #else
1921 static inline int serial_imx_probe_dt(struct imx_port *sport,
1922 		struct platform_device *pdev)
1923 {
1924 	return 1;
1925 }
1926 #endif
1927 
1928 static void serial_imx_probe_pdata(struct imx_port *sport,
1929 		struct platform_device *pdev)
1930 {
1931 	struct imxuart_platform_data *pdata = dev_get_platdata(&pdev->dev);
1932 
1933 	sport->port.line = pdev->id;
1934 	sport->devdata = (struct imx_uart_data	*) pdev->id_entry->driver_data;
1935 
1936 	if (!pdata)
1937 		return;
1938 
1939 	if (pdata->flags & IMXUART_HAVE_RTSCTS)
1940 		sport->have_rtscts = 1;
1941 
1942 	if (pdata->flags & IMXUART_IRDA)
1943 		sport->use_irda = 1;
1944 }
1945 
1946 static int serial_imx_probe(struct platform_device *pdev)
1947 {
1948 	struct imx_port *sport;
1949 	struct imxuart_platform_data *pdata;
1950 	void __iomem *base;
1951 	int ret = 0;
1952 	struct resource *res;
1953 
1954 	sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL);
1955 	if (!sport)
1956 		return -ENOMEM;
1957 
1958 	ret = serial_imx_probe_dt(sport, pdev);
1959 	if (ret > 0)
1960 		serial_imx_probe_pdata(sport, pdev);
1961 	else if (ret < 0)
1962 		return ret;
1963 
1964 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1965 	if (!res)
1966 		return -ENODEV;
1967 
1968 	base = devm_ioremap(&pdev->dev, res->start, PAGE_SIZE);
1969 	if (!base)
1970 		return -ENOMEM;
1971 
1972 	sport->port.dev = &pdev->dev;
1973 	sport->port.mapbase = res->start;
1974 	sport->port.membase = base;
1975 	sport->port.type = PORT_IMX,
1976 	sport->port.iotype = UPIO_MEM;
1977 	sport->port.irq = platform_get_irq(pdev, 0);
1978 	sport->rxirq = platform_get_irq(pdev, 0);
1979 	sport->txirq = platform_get_irq(pdev, 1);
1980 	sport->rtsirq = platform_get_irq(pdev, 2);
1981 	sport->port.fifosize = 32;
1982 	sport->port.ops = &imx_pops;
1983 	sport->port.flags = UPF_BOOT_AUTOCONF;
1984 	init_timer(&sport->timer);
1985 	sport->timer.function = imx_timeout;
1986 	sport->timer.data     = (unsigned long)sport;
1987 
1988 	sport->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
1989 	if (IS_ERR(sport->clk_ipg)) {
1990 		ret = PTR_ERR(sport->clk_ipg);
1991 		dev_err(&pdev->dev, "failed to get ipg clk: %d\n", ret);
1992 		return ret;
1993 	}
1994 
1995 	sport->clk_per = devm_clk_get(&pdev->dev, "per");
1996 	if (IS_ERR(sport->clk_per)) {
1997 		ret = PTR_ERR(sport->clk_per);
1998 		dev_err(&pdev->dev, "failed to get per clk: %d\n", ret);
1999 		return ret;
2000 	}
2001 
2002 	sport->port.uartclk = clk_get_rate(sport->clk_per);
2003 
2004 	imx_ports[sport->port.line] = sport;
2005 
2006 	pdata = dev_get_platdata(&pdev->dev);
2007 	if (pdata && pdata->init) {
2008 		ret = pdata->init(pdev);
2009 		if (ret)
2010 			return ret;
2011 	}
2012 
2013 	ret = uart_add_one_port(&imx_reg, &sport->port);
2014 	if (ret)
2015 		goto deinit;
2016 	platform_set_drvdata(pdev, sport);
2017 
2018 	return 0;
2019 deinit:
2020 	if (pdata && pdata->exit)
2021 		pdata->exit(pdev);
2022 	return ret;
2023 }
2024 
2025 static int serial_imx_remove(struct platform_device *pdev)
2026 {
2027 	struct imxuart_platform_data *pdata;
2028 	struct imx_port *sport = platform_get_drvdata(pdev);
2029 
2030 	pdata = dev_get_platdata(&pdev->dev);
2031 
2032 	uart_remove_one_port(&imx_reg, &sport->port);
2033 
2034 	if (pdata && pdata->exit)
2035 		pdata->exit(pdev);
2036 
2037 	return 0;
2038 }
2039 
2040 static struct platform_driver serial_imx_driver = {
2041 	.probe		= serial_imx_probe,
2042 	.remove		= serial_imx_remove,
2043 
2044 	.suspend	= serial_imx_suspend,
2045 	.resume		= serial_imx_resume,
2046 	.id_table	= imx_uart_devtype,
2047 	.driver		= {
2048 		.name	= "imx-uart",
2049 		.owner	= THIS_MODULE,
2050 		.of_match_table = imx_uart_dt_ids,
2051 	},
2052 };
2053 
2054 static int __init imx_serial_init(void)
2055 {
2056 	int ret;
2057 
2058 	pr_info("Serial: IMX driver\n");
2059 
2060 	ret = uart_register_driver(&imx_reg);
2061 	if (ret)
2062 		return ret;
2063 
2064 	ret = platform_driver_register(&serial_imx_driver);
2065 	if (ret != 0)
2066 		uart_unregister_driver(&imx_reg);
2067 
2068 	return ret;
2069 }
2070 
2071 static void __exit imx_serial_exit(void)
2072 {
2073 	platform_driver_unregister(&serial_imx_driver);
2074 	uart_unregister_driver(&imx_reg);
2075 }
2076 
2077 module_init(imx_serial_init);
2078 module_exit(imx_serial_exit);
2079 
2080 MODULE_AUTHOR("Sascha Hauer");
2081 MODULE_DESCRIPTION("IMX generic serial port driver");
2082 MODULE_LICENSE("GPL");
2083 MODULE_ALIAS("platform:imx-uart");
2084