xref: /openbmc/linux/drivers/tty/serial/imx.c (revision 8b036556)
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_DUMMY_READ (1<<16)
78 #define URXD_CHARRDY	(1<<15)
79 #define URXD_ERR	(1<<14)
80 #define URXD_OVRRUN	(1<<13)
81 #define URXD_FRMERR	(1<<12)
82 #define URXD_BRK	(1<<11)
83 #define URXD_PRERR	(1<<10)
84 #define URXD_RX_DATA	(0xFF<<0)
85 #define UCR1_ADEN	(1<<15) /* Auto detect interrupt */
86 #define UCR1_ADBR	(1<<14) /* Auto detect baud rate */
87 #define UCR1_TRDYEN	(1<<13) /* Transmitter ready interrupt enable */
88 #define UCR1_IDEN	(1<<12) /* Idle condition interrupt */
89 #define UCR1_ICD_REG(x) (((x) & 3) << 10) /* idle condition detect */
90 #define UCR1_RRDYEN	(1<<9)	/* Recv ready interrupt enable */
91 #define UCR1_RDMAEN	(1<<8)	/* Recv ready DMA enable */
92 #define UCR1_IREN	(1<<7)	/* Infrared interface enable */
93 #define UCR1_TXMPTYEN	(1<<6)	/* Transimitter empty interrupt enable */
94 #define UCR1_RTSDEN	(1<<5)	/* RTS delta interrupt enable */
95 #define UCR1_SNDBRK	(1<<4)	/* Send break */
96 #define UCR1_TDMAEN	(1<<3)	/* Transmitter ready DMA enable */
97 #define IMX1_UCR1_UARTCLKEN (1<<2) /* UART clock enabled, i.mx1 only */
98 #define UCR1_ATDMAEN    (1<<2)  /* Aging DMA Timer Enable */
99 #define UCR1_DOZE	(1<<1)	/* Doze */
100 #define UCR1_UARTEN	(1<<0)	/* UART enabled */
101 #define UCR2_ESCI	(1<<15)	/* Escape seq interrupt enable */
102 #define UCR2_IRTS	(1<<14)	/* Ignore RTS pin */
103 #define UCR2_CTSC	(1<<13)	/* CTS pin control */
104 #define UCR2_CTS	(1<<12)	/* Clear to send */
105 #define UCR2_ESCEN	(1<<11)	/* Escape enable */
106 #define UCR2_PREN	(1<<8)	/* Parity enable */
107 #define UCR2_PROE	(1<<7)	/* Parity odd/even */
108 #define UCR2_STPB	(1<<6)	/* Stop */
109 #define UCR2_WS		(1<<5)	/* Word size */
110 #define UCR2_RTSEN	(1<<4)	/* Request to send interrupt enable */
111 #define UCR2_ATEN	(1<<3)	/* Aging Timer Enable */
112 #define UCR2_TXEN	(1<<2)	/* Transmitter enabled */
113 #define UCR2_RXEN	(1<<1)	/* Receiver enabled */
114 #define UCR2_SRST	(1<<0)	/* SW reset */
115 #define UCR3_DTREN	(1<<13) /* DTR interrupt enable */
116 #define UCR3_PARERREN	(1<<12) /* Parity enable */
117 #define UCR3_FRAERREN	(1<<11) /* Frame error interrupt enable */
118 #define UCR3_DSR	(1<<10) /* Data set ready */
119 #define UCR3_DCD	(1<<9)	/* Data carrier detect */
120 #define UCR3_RI		(1<<8)	/* Ring indicator */
121 #define UCR3_ADNIMP	(1<<7)	/* Autobaud Detection Not Improved */
122 #define UCR3_RXDSEN	(1<<6)	/* Receive status interrupt enable */
123 #define UCR3_AIRINTEN	(1<<5)	/* Async IR wake interrupt enable */
124 #define UCR3_AWAKEN	(1<<4)	/* Async wake interrupt enable */
125 #define IMX21_UCR3_RXDMUXSEL	(1<<2)	/* RXD Muxed Input Select */
126 #define UCR3_INVT	(1<<1)	/* Inverted Infrared transmission */
127 #define UCR3_BPEN	(1<<0)	/* Preset registers enable */
128 #define UCR4_CTSTL_SHF	10	/* CTS trigger level shift */
129 #define UCR4_CTSTL_MASK	0x3F	/* CTS trigger is 6 bits wide */
130 #define UCR4_INVR	(1<<9)	/* Inverted infrared reception */
131 #define UCR4_ENIRI	(1<<8)	/* Serial infrared interrupt enable */
132 #define UCR4_WKEN	(1<<7)	/* Wake interrupt enable */
133 #define UCR4_REF16	(1<<6)	/* Ref freq 16 MHz */
134 #define UCR4_IDDMAEN    (1<<6)  /* DMA IDLE Condition Detected */
135 #define UCR4_IRSC	(1<<5)	/* IR special case */
136 #define UCR4_TCEN	(1<<3)	/* Transmit complete interrupt enable */
137 #define UCR4_BKEN	(1<<2)	/* Break condition interrupt enable */
138 #define UCR4_OREN	(1<<1)	/* Receiver overrun interrupt enable */
139 #define UCR4_DREN	(1<<0)	/* Recv data ready interrupt enable */
140 #define UFCR_RXTL_SHF	0	/* Receiver trigger level shift */
141 #define UFCR_DCEDTE	(1<<6)	/* DCE/DTE mode select */
142 #define UFCR_RFDIV	(7<<7)	/* Reference freq divider mask */
143 #define UFCR_RFDIV_REG(x)	(((x) < 7 ? 6 - (x) : 6) << 7)
144 #define UFCR_TXTL_SHF	10	/* Transmitter trigger level shift */
145 #define USR1_PARITYERR	(1<<15) /* Parity error interrupt flag */
146 #define USR1_RTSS	(1<<14) /* RTS pin status */
147 #define USR1_TRDY	(1<<13) /* Transmitter ready interrupt/dma flag */
148 #define USR1_RTSD	(1<<12) /* RTS delta */
149 #define USR1_ESCF	(1<<11) /* Escape seq interrupt flag */
150 #define USR1_FRAMERR	(1<<10) /* Frame error interrupt flag */
151 #define USR1_RRDY	(1<<9)	 /* Receiver ready interrupt/dma flag */
152 #define USR1_TIMEOUT	(1<<7)	 /* Receive timeout interrupt status */
153 #define USR1_RXDS	 (1<<6)	 /* Receiver idle interrupt flag */
154 #define USR1_AIRINT	 (1<<5)	 /* Async IR wake interrupt flag */
155 #define USR1_AWAKE	 (1<<4)	 /* Aysnc wake interrupt flag */
156 #define USR2_ADET	 (1<<15) /* Auto baud rate detect complete */
157 #define USR2_TXFE	 (1<<14) /* Transmit buffer FIFO empty */
158 #define USR2_DTRF	 (1<<13) /* DTR edge interrupt flag */
159 #define USR2_IDLE	 (1<<12) /* Idle condition */
160 #define USR2_IRINT	 (1<<8)	 /* Serial infrared interrupt flag */
161 #define USR2_WAKE	 (1<<7)	 /* Wake */
162 #define USR2_RTSF	 (1<<4)	 /* RTS edge interrupt flag */
163 #define USR2_TXDC	 (1<<3)	 /* Transmitter complete */
164 #define USR2_BRCD	 (1<<2)	 /* Break condition */
165 #define USR2_ORE	(1<<1)	 /* Overrun error */
166 #define USR2_RDR	(1<<0)	 /* Recv data ready */
167 #define UTS_FRCPERR	(1<<13) /* Force parity error */
168 #define UTS_LOOP	(1<<12)	 /* Loop tx and rx */
169 #define UTS_TXEMPTY	 (1<<6)	 /* TxFIFO empty */
170 #define UTS_RXEMPTY	 (1<<5)	 /* RxFIFO empty */
171 #define UTS_TXFULL	 (1<<4)	 /* TxFIFO full */
172 #define UTS_RXFULL	 (1<<3)	 /* RxFIFO full */
173 #define UTS_SOFTRST	 (1<<0)	 /* Software reset */
174 
175 /* We've been assigned a range on the "Low-density serial ports" major */
176 #define SERIAL_IMX_MAJOR	207
177 #define MINOR_START		16
178 #define DEV_NAME		"ttymxc"
179 
180 /*
181  * This determines how often we check the modem status signals
182  * for any change.  They generally aren't connected to an IRQ
183  * so we have to poll them.  We also check immediately before
184  * filling the TX fifo incase CTS has been dropped.
185  */
186 #define MCTRL_TIMEOUT	(250*HZ/1000)
187 
188 #define DRIVER_NAME "IMX-uart"
189 
190 #define UART_NR 8
191 
192 /* i.mx21 type uart runs on all i.mx except i.mx1 */
193 enum imx_uart_type {
194 	IMX1_UART,
195 	IMX21_UART,
196 	IMX6Q_UART,
197 };
198 
199 /* device type dependent stuff */
200 struct imx_uart_data {
201 	unsigned uts_reg;
202 	enum imx_uart_type devtype;
203 };
204 
205 struct imx_port {
206 	struct uart_port	port;
207 	struct timer_list	timer;
208 	unsigned int		old_status;
209 	int			txirq, rxirq, rtsirq;
210 	unsigned int		have_rtscts:1;
211 	unsigned int		dte_mode:1;
212 	unsigned int		use_irda:1;
213 	unsigned int		irda_inv_rx:1;
214 	unsigned int		irda_inv_tx:1;
215 	unsigned short		trcv_delay; /* transceiver delay */
216 	struct clk		*clk_ipg;
217 	struct clk		*clk_per;
218 	const struct imx_uart_data *devdata;
219 
220 	/* DMA fields */
221 	unsigned int		dma_is_inited:1;
222 	unsigned int		dma_is_enabled:1;
223 	unsigned int		dma_is_rxing:1;
224 	unsigned int		dma_is_txing:1;
225 	struct dma_chan		*dma_chan_rx, *dma_chan_tx;
226 	struct scatterlist	rx_sgl, tx_sgl[2];
227 	void			*rx_buf;
228 	unsigned int		tx_bytes;
229 	unsigned int		dma_tx_nents;
230 	wait_queue_head_t	dma_wait;
231 };
232 
233 struct imx_port_ucrs {
234 	unsigned int	ucr1;
235 	unsigned int	ucr2;
236 	unsigned int	ucr3;
237 };
238 
239 #ifdef CONFIG_IRDA
240 #define USE_IRDA(sport)	((sport)->use_irda)
241 #else
242 #define USE_IRDA(sport)	(0)
243 #endif
244 
245 static struct imx_uart_data imx_uart_devdata[] = {
246 	[IMX1_UART] = {
247 		.uts_reg = IMX1_UTS,
248 		.devtype = IMX1_UART,
249 	},
250 	[IMX21_UART] = {
251 		.uts_reg = IMX21_UTS,
252 		.devtype = IMX21_UART,
253 	},
254 	[IMX6Q_UART] = {
255 		.uts_reg = IMX21_UTS,
256 		.devtype = IMX6Q_UART,
257 	},
258 };
259 
260 static struct platform_device_id imx_uart_devtype[] = {
261 	{
262 		.name = "imx1-uart",
263 		.driver_data = (kernel_ulong_t) &imx_uart_devdata[IMX1_UART],
264 	}, {
265 		.name = "imx21-uart",
266 		.driver_data = (kernel_ulong_t) &imx_uart_devdata[IMX21_UART],
267 	}, {
268 		.name = "imx6q-uart",
269 		.driver_data = (kernel_ulong_t) &imx_uart_devdata[IMX6Q_UART],
270 	}, {
271 		/* sentinel */
272 	}
273 };
274 MODULE_DEVICE_TABLE(platform, imx_uart_devtype);
275 
276 static struct of_device_id imx_uart_dt_ids[] = {
277 	{ .compatible = "fsl,imx6q-uart", .data = &imx_uart_devdata[IMX6Q_UART], },
278 	{ .compatible = "fsl,imx1-uart", .data = &imx_uart_devdata[IMX1_UART], },
279 	{ .compatible = "fsl,imx21-uart", .data = &imx_uart_devdata[IMX21_UART], },
280 	{ /* sentinel */ }
281 };
282 MODULE_DEVICE_TABLE(of, imx_uart_dt_ids);
283 
284 static inline unsigned uts_reg(struct imx_port *sport)
285 {
286 	return sport->devdata->uts_reg;
287 }
288 
289 static inline int is_imx1_uart(struct imx_port *sport)
290 {
291 	return sport->devdata->devtype == IMX1_UART;
292 }
293 
294 static inline int is_imx21_uart(struct imx_port *sport)
295 {
296 	return sport->devdata->devtype == IMX21_UART;
297 }
298 
299 static inline int is_imx6q_uart(struct imx_port *sport)
300 {
301 	return sport->devdata->devtype == IMX6Q_UART;
302 }
303 /*
304  * Save and restore functions for UCR1, UCR2 and UCR3 registers
305  */
306 #if defined(CONFIG_SERIAL_IMX_CONSOLE)
307 static void imx_port_ucrs_save(struct uart_port *port,
308 			       struct imx_port_ucrs *ucr)
309 {
310 	/* save control registers */
311 	ucr->ucr1 = readl(port->membase + UCR1);
312 	ucr->ucr2 = readl(port->membase + UCR2);
313 	ucr->ucr3 = readl(port->membase + UCR3);
314 }
315 
316 static void imx_port_ucrs_restore(struct uart_port *port,
317 				  struct imx_port_ucrs *ucr)
318 {
319 	/* restore control registers */
320 	writel(ucr->ucr1, port->membase + UCR1);
321 	writel(ucr->ucr2, port->membase + UCR2);
322 	writel(ucr->ucr3, port->membase + UCR3);
323 }
324 #endif
325 
326 /*
327  * Handle any change of modem status signal since we were last called.
328  */
329 static void imx_mctrl_check(struct imx_port *sport)
330 {
331 	unsigned int status, changed;
332 
333 	status = sport->port.ops->get_mctrl(&sport->port);
334 	changed = status ^ sport->old_status;
335 
336 	if (changed == 0)
337 		return;
338 
339 	sport->old_status = status;
340 
341 	if (changed & TIOCM_RI)
342 		sport->port.icount.rng++;
343 	if (changed & TIOCM_DSR)
344 		sport->port.icount.dsr++;
345 	if (changed & TIOCM_CAR)
346 		uart_handle_dcd_change(&sport->port, status & TIOCM_CAR);
347 	if (changed & TIOCM_CTS)
348 		uart_handle_cts_change(&sport->port, status & TIOCM_CTS);
349 
350 	wake_up_interruptible(&sport->port.state->port.delta_msr_wait);
351 }
352 
353 /*
354  * This is our per-port timeout handler, for checking the
355  * modem status signals.
356  */
357 static void imx_timeout(unsigned long data)
358 {
359 	struct imx_port *sport = (struct imx_port *)data;
360 	unsigned long flags;
361 
362 	if (sport->port.state) {
363 		spin_lock_irqsave(&sport->port.lock, flags);
364 		imx_mctrl_check(sport);
365 		spin_unlock_irqrestore(&sport->port.lock, flags);
366 
367 		mod_timer(&sport->timer, jiffies + MCTRL_TIMEOUT);
368 	}
369 }
370 
371 /*
372  * interrupts disabled on entry
373  */
374 static void imx_stop_tx(struct uart_port *port)
375 {
376 	struct imx_port *sport = (struct imx_port *)port;
377 	unsigned long temp;
378 
379 	if (USE_IRDA(sport)) {
380 		/* half duplex - wait for end of transmission */
381 		int n = 256;
382 		while ((--n > 0) &&
383 		      !(readl(sport->port.membase + USR2) & USR2_TXDC)) {
384 			udelay(5);
385 			barrier();
386 		}
387 		/*
388 		 * irda transceiver - wait a bit more to avoid
389 		 * cutoff, hardware dependent
390 		 */
391 		udelay(sport->trcv_delay);
392 
393 		/*
394 		 * half duplex - reactivate receive mode,
395 		 * flush receive pipe echo crap
396 		 */
397 		if (readl(sport->port.membase + USR2) & USR2_TXDC) {
398 			temp = readl(sport->port.membase + UCR1);
399 			temp &= ~(UCR1_TXMPTYEN | UCR1_TRDYEN);
400 			writel(temp, sport->port.membase + UCR1);
401 
402 			temp = readl(sport->port.membase + UCR4);
403 			temp &= ~(UCR4_TCEN);
404 			writel(temp, sport->port.membase + UCR4);
405 
406 			while (readl(sport->port.membase + URXD0) &
407 			       URXD_CHARRDY)
408 				barrier();
409 
410 			temp = readl(sport->port.membase + UCR1);
411 			temp |= UCR1_RRDYEN;
412 			writel(temp, sport->port.membase + UCR1);
413 
414 			temp = readl(sport->port.membase + UCR4);
415 			temp |= UCR4_DREN;
416 			writel(temp, sport->port.membase + UCR4);
417 		}
418 		return;
419 	}
420 
421 	/*
422 	 * We are maybe in the SMP context, so if the DMA TX thread is running
423 	 * on other cpu, we have to wait for it to finish.
424 	 */
425 	if (sport->dma_is_enabled && sport->dma_is_txing)
426 		return;
427 
428 	temp = readl(sport->port.membase + UCR1);
429 	writel(temp & ~UCR1_TXMPTYEN, sport->port.membase + UCR1);
430 }
431 
432 /*
433  * interrupts disabled on entry
434  */
435 static void imx_stop_rx(struct uart_port *port)
436 {
437 	struct imx_port *sport = (struct imx_port *)port;
438 	unsigned long temp;
439 
440 	if (sport->dma_is_enabled && sport->dma_is_rxing) {
441 		if (sport->port.suspended) {
442 			dmaengine_terminate_all(sport->dma_chan_rx);
443 			sport->dma_is_rxing = 0;
444 		} else {
445 			return;
446 		}
447 	}
448 
449 	temp = readl(sport->port.membase + UCR2);
450 	writel(temp & ~UCR2_RXEN, sport->port.membase + UCR2);
451 
452 	/* disable the `Receiver Ready Interrrupt` */
453 	temp = readl(sport->port.membase + UCR1);
454 	writel(temp & ~UCR1_RRDYEN, sport->port.membase + UCR1);
455 }
456 
457 /*
458  * Set the modem control timer to fire immediately.
459  */
460 static void imx_enable_ms(struct uart_port *port)
461 {
462 	struct imx_port *sport = (struct imx_port *)port;
463 
464 	mod_timer(&sport->timer, jiffies);
465 }
466 
467 static void imx_dma_tx(struct imx_port *sport);
468 static inline void imx_transmit_buffer(struct imx_port *sport)
469 {
470 	struct circ_buf *xmit = &sport->port.state->xmit;
471 	unsigned long temp;
472 
473 	if (sport->port.x_char) {
474 		/* Send next char */
475 		writel(sport->port.x_char, sport->port.membase + URTX0);
476 		sport->port.icount.tx++;
477 		sport->port.x_char = 0;
478 		return;
479 	}
480 
481 	if (uart_circ_empty(xmit) || uart_tx_stopped(&sport->port)) {
482 		imx_stop_tx(&sport->port);
483 		return;
484 	}
485 
486 	if (sport->dma_is_enabled) {
487 		/*
488 		 * We've just sent a X-char Ensure the TX DMA is enabled
489 		 * and the TX IRQ is disabled.
490 		 **/
491 		temp = readl(sport->port.membase + UCR1);
492 		temp &= ~UCR1_TXMPTYEN;
493 		if (sport->dma_is_txing) {
494 			temp |= UCR1_TDMAEN;
495 			writel(temp, sport->port.membase + UCR1);
496 		} else {
497 			writel(temp, sport->port.membase + UCR1);
498 			imx_dma_tx(sport);
499 		}
500 	}
501 
502 	while (!uart_circ_empty(xmit) &&
503 	       !(readl(sport->port.membase + uts_reg(sport)) & UTS_TXFULL)) {
504 		/* send xmit->buf[xmit->tail]
505 		 * out the port here */
506 		writel(xmit->buf[xmit->tail], sport->port.membase + URTX0);
507 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
508 		sport->port.icount.tx++;
509 	}
510 
511 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
512 		uart_write_wakeup(&sport->port);
513 
514 	if (uart_circ_empty(xmit))
515 		imx_stop_tx(&sport->port);
516 }
517 
518 static void dma_tx_callback(void *data)
519 {
520 	struct imx_port *sport = data;
521 	struct scatterlist *sgl = &sport->tx_sgl[0];
522 	struct circ_buf *xmit = &sport->port.state->xmit;
523 	unsigned long flags;
524 	unsigned long temp;
525 
526 	spin_lock_irqsave(&sport->port.lock, flags);
527 
528 	dma_unmap_sg(sport->port.dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE);
529 
530 	temp = readl(sport->port.membase + UCR1);
531 	temp &= ~UCR1_TDMAEN;
532 	writel(temp, sport->port.membase + UCR1);
533 
534 	/* update the stat */
535 	xmit->tail = (xmit->tail + sport->tx_bytes) & (UART_XMIT_SIZE - 1);
536 	sport->port.icount.tx += sport->tx_bytes;
537 
538 	dev_dbg(sport->port.dev, "we finish the TX DMA.\n");
539 
540 	sport->dma_is_txing = 0;
541 
542 	spin_unlock_irqrestore(&sport->port.lock, flags);
543 
544 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
545 		uart_write_wakeup(&sport->port);
546 
547 	if (waitqueue_active(&sport->dma_wait)) {
548 		wake_up(&sport->dma_wait);
549 		dev_dbg(sport->port.dev, "exit in %s.\n", __func__);
550 		return;
551 	}
552 
553 	spin_lock_irqsave(&sport->port.lock, flags);
554 	if (!uart_circ_empty(xmit) && !uart_tx_stopped(&sport->port))
555 		imx_dma_tx(sport);
556 	spin_unlock_irqrestore(&sport->port.lock, flags);
557 }
558 
559 static void imx_dma_tx(struct imx_port *sport)
560 {
561 	struct circ_buf *xmit = &sport->port.state->xmit;
562 	struct scatterlist *sgl = sport->tx_sgl;
563 	struct dma_async_tx_descriptor *desc;
564 	struct dma_chan	*chan = sport->dma_chan_tx;
565 	struct device *dev = sport->port.dev;
566 	unsigned long temp;
567 	int ret;
568 
569 	if (sport->dma_is_txing)
570 		return;
571 
572 	sport->tx_bytes = uart_circ_chars_pending(xmit);
573 
574 	if (xmit->tail < xmit->head) {
575 		sport->dma_tx_nents = 1;
576 		sg_init_one(sgl, xmit->buf + xmit->tail, sport->tx_bytes);
577 	} else {
578 		sport->dma_tx_nents = 2;
579 		sg_init_table(sgl, 2);
580 		sg_set_buf(sgl, xmit->buf + xmit->tail,
581 				UART_XMIT_SIZE - xmit->tail);
582 		sg_set_buf(sgl + 1, xmit->buf, xmit->head);
583 	}
584 
585 	ret = dma_map_sg(dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE);
586 	if (ret == 0) {
587 		dev_err(dev, "DMA mapping error for TX.\n");
588 		return;
589 	}
590 	desc = dmaengine_prep_slave_sg(chan, sgl, sport->dma_tx_nents,
591 					DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT);
592 	if (!desc) {
593 		dma_unmap_sg(dev, sgl, sport->dma_tx_nents,
594 			     DMA_TO_DEVICE);
595 		dev_err(dev, "We cannot prepare for the TX slave dma!\n");
596 		return;
597 	}
598 	desc->callback = dma_tx_callback;
599 	desc->callback_param = sport;
600 
601 	dev_dbg(dev, "TX: prepare to send %lu bytes by DMA.\n",
602 			uart_circ_chars_pending(xmit));
603 
604 	temp = readl(sport->port.membase + UCR1);
605 	temp |= UCR1_TDMAEN;
606 	writel(temp, sport->port.membase + UCR1);
607 
608 	/* fire it */
609 	sport->dma_is_txing = 1;
610 	dmaengine_submit(desc);
611 	dma_async_issue_pending(chan);
612 	return;
613 }
614 
615 /*
616  * interrupts disabled on entry
617  */
618 static void imx_start_tx(struct uart_port *port)
619 {
620 	struct imx_port *sport = (struct imx_port *)port;
621 	unsigned long temp;
622 
623 	if (USE_IRDA(sport)) {
624 		/* half duplex in IrDA mode; have to disable receive mode */
625 		temp = readl(sport->port.membase + UCR4);
626 		temp &= ~(UCR4_DREN);
627 		writel(temp, sport->port.membase + UCR4);
628 
629 		temp = readl(sport->port.membase + UCR1);
630 		temp &= ~(UCR1_RRDYEN);
631 		writel(temp, sport->port.membase + UCR1);
632 	}
633 
634 	if (!sport->dma_is_enabled) {
635 		temp = readl(sport->port.membase + UCR1);
636 		writel(temp | UCR1_TXMPTYEN, sport->port.membase + UCR1);
637 	}
638 
639 	if (USE_IRDA(sport)) {
640 		temp = readl(sport->port.membase + UCR1);
641 		temp |= UCR1_TRDYEN;
642 		writel(temp, sport->port.membase + UCR1);
643 
644 		temp = readl(sport->port.membase + UCR4);
645 		temp |= UCR4_TCEN;
646 		writel(temp, sport->port.membase + UCR4);
647 	}
648 
649 	if (sport->dma_is_enabled) {
650 		if (sport->port.x_char) {
651 			/* We have X-char to send, so enable TX IRQ and
652 			 * disable TX DMA to let TX interrupt to send X-char */
653 			temp = readl(sport->port.membase + UCR1);
654 			temp &= ~UCR1_TDMAEN;
655 			temp |= UCR1_TXMPTYEN;
656 			writel(temp, sport->port.membase + UCR1);
657 			return;
658 		}
659 
660 		if (!uart_circ_empty(&port->state->xmit) &&
661 		    !uart_tx_stopped(port))
662 			imx_dma_tx(sport);
663 		return;
664 	}
665 }
666 
667 static irqreturn_t imx_rtsint(int irq, void *dev_id)
668 {
669 	struct imx_port *sport = dev_id;
670 	unsigned int val;
671 	unsigned long flags;
672 
673 	spin_lock_irqsave(&sport->port.lock, flags);
674 
675 	writel(USR1_RTSD, sport->port.membase + USR1);
676 	val = readl(sport->port.membase + USR1) & USR1_RTSS;
677 	uart_handle_cts_change(&sport->port, !!val);
678 	wake_up_interruptible(&sport->port.state->port.delta_msr_wait);
679 
680 	spin_unlock_irqrestore(&sport->port.lock, flags);
681 	return IRQ_HANDLED;
682 }
683 
684 static irqreturn_t imx_txint(int irq, void *dev_id)
685 {
686 	struct imx_port *sport = dev_id;
687 	unsigned long flags;
688 
689 	spin_lock_irqsave(&sport->port.lock, flags);
690 	imx_transmit_buffer(sport);
691 	spin_unlock_irqrestore(&sport->port.lock, flags);
692 	return IRQ_HANDLED;
693 }
694 
695 static irqreturn_t imx_rxint(int irq, void *dev_id)
696 {
697 	struct imx_port *sport = dev_id;
698 	unsigned int rx, flg, ignored = 0;
699 	struct tty_port *port = &sport->port.state->port;
700 	unsigned long flags, temp;
701 
702 	spin_lock_irqsave(&sport->port.lock, flags);
703 
704 	while (readl(sport->port.membase + USR2) & USR2_RDR) {
705 		flg = TTY_NORMAL;
706 		sport->port.icount.rx++;
707 
708 		rx = readl(sport->port.membase + URXD0);
709 
710 		temp = readl(sport->port.membase + USR2);
711 		if (temp & USR2_BRCD) {
712 			writel(USR2_BRCD, sport->port.membase + USR2);
713 			if (uart_handle_break(&sport->port))
714 				continue;
715 		}
716 
717 		if (uart_handle_sysrq_char(&sport->port, (unsigned char)rx))
718 			continue;
719 
720 		if (unlikely(rx & URXD_ERR)) {
721 			if (rx & URXD_BRK)
722 				sport->port.icount.brk++;
723 			else if (rx & URXD_PRERR)
724 				sport->port.icount.parity++;
725 			else if (rx & URXD_FRMERR)
726 				sport->port.icount.frame++;
727 			if (rx & URXD_OVRRUN)
728 				sport->port.icount.overrun++;
729 
730 			if (rx & sport->port.ignore_status_mask) {
731 				if (++ignored > 100)
732 					goto out;
733 				continue;
734 			}
735 
736 			rx &= (sport->port.read_status_mask | 0xFF);
737 
738 			if (rx & URXD_BRK)
739 				flg = TTY_BREAK;
740 			else if (rx & URXD_PRERR)
741 				flg = TTY_PARITY;
742 			else if (rx & URXD_FRMERR)
743 				flg = TTY_FRAME;
744 			if (rx & URXD_OVRRUN)
745 				flg = TTY_OVERRUN;
746 
747 #ifdef SUPPORT_SYSRQ
748 			sport->port.sysrq = 0;
749 #endif
750 		}
751 
752 		if (sport->port.ignore_status_mask & URXD_DUMMY_READ)
753 			goto out;
754 
755 		tty_insert_flip_char(port, rx, flg);
756 	}
757 
758 out:
759 	spin_unlock_irqrestore(&sport->port.lock, flags);
760 	tty_flip_buffer_push(port);
761 	return IRQ_HANDLED;
762 }
763 
764 static int start_rx_dma(struct imx_port *sport);
765 /*
766  * If the RXFIFO is filled with some data, and then we
767  * arise a DMA operation to receive them.
768  */
769 static void imx_dma_rxint(struct imx_port *sport)
770 {
771 	unsigned long temp;
772 	unsigned long flags;
773 
774 	spin_lock_irqsave(&sport->port.lock, flags);
775 
776 	temp = readl(sport->port.membase + USR2);
777 	if ((temp & USR2_RDR) && !sport->dma_is_rxing) {
778 		sport->dma_is_rxing = 1;
779 
780 		/* disable the `Recerver Ready Interrrupt` */
781 		temp = readl(sport->port.membase + UCR1);
782 		temp &= ~(UCR1_RRDYEN);
783 		writel(temp, sport->port.membase + UCR1);
784 
785 		/* tell the DMA to receive the data. */
786 		start_rx_dma(sport);
787 	}
788 
789 	spin_unlock_irqrestore(&sport->port.lock, flags);
790 }
791 
792 static irqreturn_t imx_int(int irq, void *dev_id)
793 {
794 	struct imx_port *sport = dev_id;
795 	unsigned int sts;
796 	unsigned int sts2;
797 
798 	sts = readl(sport->port.membase + USR1);
799 
800 	if (sts & USR1_RRDY) {
801 		if (sport->dma_is_enabled)
802 			imx_dma_rxint(sport);
803 		else
804 			imx_rxint(irq, dev_id);
805 	}
806 
807 	if (sts & USR1_TRDY &&
808 			readl(sport->port.membase + UCR1) & UCR1_TXMPTYEN)
809 		imx_txint(irq, dev_id);
810 
811 	if (sts & USR1_RTSD)
812 		imx_rtsint(irq, dev_id);
813 
814 	if (sts & USR1_AWAKE)
815 		writel(USR1_AWAKE, sport->port.membase + USR1);
816 
817 	sts2 = readl(sport->port.membase + USR2);
818 	if (sts2 & USR2_ORE) {
819 		dev_err(sport->port.dev, "Rx FIFO overrun\n");
820 		sport->port.icount.overrun++;
821 		writel(sts2 | USR2_ORE, sport->port.membase + USR2);
822 	}
823 
824 	return IRQ_HANDLED;
825 }
826 
827 /*
828  * Return TIOCSER_TEMT when transmitter is not busy.
829  */
830 static unsigned int imx_tx_empty(struct uart_port *port)
831 {
832 	struct imx_port *sport = (struct imx_port *)port;
833 	unsigned int ret;
834 
835 	ret = (readl(sport->port.membase + USR2) & USR2_TXDC) ?  TIOCSER_TEMT : 0;
836 
837 	/* If the TX DMA is working, return 0. */
838 	if (sport->dma_is_enabled && sport->dma_is_txing)
839 		ret = 0;
840 
841 	return ret;
842 }
843 
844 /*
845  * We have a modem side uart, so the meanings of RTS and CTS are inverted.
846  */
847 static unsigned int imx_get_mctrl(struct uart_port *port)
848 {
849 	struct imx_port *sport = (struct imx_port *)port;
850 	unsigned int tmp = TIOCM_DSR | TIOCM_CAR;
851 
852 	if (readl(sport->port.membase + USR1) & USR1_RTSS)
853 		tmp |= TIOCM_CTS;
854 
855 	if (readl(sport->port.membase + UCR2) & UCR2_CTS)
856 		tmp |= TIOCM_RTS;
857 
858 	if (readl(sport->port.membase + uts_reg(sport)) & UTS_LOOP)
859 		tmp |= TIOCM_LOOP;
860 
861 	return tmp;
862 }
863 
864 static void imx_set_mctrl(struct uart_port *port, unsigned int mctrl)
865 {
866 	struct imx_port *sport = (struct imx_port *)port;
867 	unsigned long temp;
868 
869 	temp = readl(sport->port.membase + UCR2) & ~(UCR2_CTS | UCR2_CTSC);
870 	if (mctrl & TIOCM_RTS)
871 		temp |= UCR2_CTS | UCR2_CTSC;
872 
873 	writel(temp, sport->port.membase + UCR2);
874 
875 	temp = readl(sport->port.membase + uts_reg(sport)) & ~UTS_LOOP;
876 	if (mctrl & TIOCM_LOOP)
877 		temp |= UTS_LOOP;
878 	writel(temp, sport->port.membase + uts_reg(sport));
879 }
880 
881 /*
882  * Interrupts always disabled.
883  */
884 static void imx_break_ctl(struct uart_port *port, int break_state)
885 {
886 	struct imx_port *sport = (struct imx_port *)port;
887 	unsigned long flags, temp;
888 
889 	spin_lock_irqsave(&sport->port.lock, flags);
890 
891 	temp = readl(sport->port.membase + UCR1) & ~UCR1_SNDBRK;
892 
893 	if (break_state != 0)
894 		temp |= UCR1_SNDBRK;
895 
896 	writel(temp, sport->port.membase + UCR1);
897 
898 	spin_unlock_irqrestore(&sport->port.lock, flags);
899 }
900 
901 #define TXTL 2 /* reset default */
902 #define RXTL 1 /* reset default */
903 
904 static int imx_setup_ufcr(struct imx_port *sport, unsigned int mode)
905 {
906 	unsigned int val;
907 
908 	/* set receiver / transmitter trigger level */
909 	val = readl(sport->port.membase + UFCR) & (UFCR_RFDIV | UFCR_DCEDTE);
910 	val |= TXTL << UFCR_TXTL_SHF | RXTL;
911 	writel(val, sport->port.membase + UFCR);
912 	return 0;
913 }
914 
915 #define RX_BUF_SIZE	(PAGE_SIZE)
916 static void imx_rx_dma_done(struct imx_port *sport)
917 {
918 	unsigned long temp;
919 	unsigned long flags;
920 
921 	spin_lock_irqsave(&sport->port.lock, flags);
922 
923 	/* Enable this interrupt when the RXFIFO is empty. */
924 	temp = readl(sport->port.membase + UCR1);
925 	temp |= UCR1_RRDYEN;
926 	writel(temp, sport->port.membase + UCR1);
927 
928 	sport->dma_is_rxing = 0;
929 
930 	/* Is the shutdown waiting for us? */
931 	if (waitqueue_active(&sport->dma_wait))
932 		wake_up(&sport->dma_wait);
933 
934 	spin_unlock_irqrestore(&sport->port.lock, flags);
935 }
936 
937 /*
938  * There are three kinds of RX DMA interrupts(such as in the MX6Q):
939  *   [1] the RX DMA buffer is full.
940  *   [2] the Aging timer expires(wait for 8 bytes long)
941  *   [3] the Idle Condition Detect(enabled the UCR4_IDDMAEN).
942  *
943  * The [2] is trigger when a character was been sitting in the FIFO
944  * meanwhile [3] can wait for 32 bytes long when the RX line is
945  * on IDLE state and RxFIFO is empty.
946  */
947 static void dma_rx_callback(void *data)
948 {
949 	struct imx_port *sport = data;
950 	struct dma_chan	*chan = sport->dma_chan_rx;
951 	struct scatterlist *sgl = &sport->rx_sgl;
952 	struct tty_port *port = &sport->port.state->port;
953 	struct dma_tx_state state;
954 	enum dma_status status;
955 	unsigned int count;
956 
957 	/* unmap it first */
958 	dma_unmap_sg(sport->port.dev, sgl, 1, DMA_FROM_DEVICE);
959 
960 	status = dmaengine_tx_status(chan, (dma_cookie_t)0, &state);
961 	count = RX_BUF_SIZE - state.residue;
962 	dev_dbg(sport->port.dev, "We get %d bytes.\n", count);
963 
964 	if (count) {
965 		if (!(sport->port.ignore_status_mask & URXD_DUMMY_READ))
966 			tty_insert_flip_string(port, sport->rx_buf, count);
967 		tty_flip_buffer_push(port);
968 
969 		start_rx_dma(sport);
970 	} else if (readl(sport->port.membase + USR2) & USR2_RDR) {
971 		/*
972 		 * start rx_dma directly once data in RXFIFO, more efficient
973 		 * than before:
974 		 *	1. call imx_rx_dma_done to stop dma if no data received
975 		 *	2. wait next  RDR interrupt to start dma transfer.
976 		 */
977 		start_rx_dma(sport);
978 	} else {
979 		/*
980 		 * stop dma to prevent too many IDLE event trigged if no data
981 		 * in RXFIFO
982 		 */
983 		imx_rx_dma_done(sport);
984 	}
985 }
986 
987 static int start_rx_dma(struct imx_port *sport)
988 {
989 	struct scatterlist *sgl = &sport->rx_sgl;
990 	struct dma_chan	*chan = sport->dma_chan_rx;
991 	struct device *dev = sport->port.dev;
992 	struct dma_async_tx_descriptor *desc;
993 	int ret;
994 
995 	sg_init_one(sgl, sport->rx_buf, RX_BUF_SIZE);
996 	ret = dma_map_sg(dev, sgl, 1, DMA_FROM_DEVICE);
997 	if (ret == 0) {
998 		dev_err(dev, "DMA mapping error for RX.\n");
999 		return -EINVAL;
1000 	}
1001 	desc = dmaengine_prep_slave_sg(chan, sgl, 1, DMA_DEV_TO_MEM,
1002 					DMA_PREP_INTERRUPT);
1003 	if (!desc) {
1004 		dma_unmap_sg(dev, sgl, 1, DMA_FROM_DEVICE);
1005 		dev_err(dev, "We cannot prepare for the RX slave dma!\n");
1006 		return -EINVAL;
1007 	}
1008 	desc->callback = dma_rx_callback;
1009 	desc->callback_param = sport;
1010 
1011 	dev_dbg(dev, "RX: prepare for the DMA.\n");
1012 	dmaengine_submit(desc);
1013 	dma_async_issue_pending(chan);
1014 	return 0;
1015 }
1016 
1017 static void imx_uart_dma_exit(struct imx_port *sport)
1018 {
1019 	if (sport->dma_chan_rx) {
1020 		dma_release_channel(sport->dma_chan_rx);
1021 		sport->dma_chan_rx = NULL;
1022 
1023 		kfree(sport->rx_buf);
1024 		sport->rx_buf = NULL;
1025 	}
1026 
1027 	if (sport->dma_chan_tx) {
1028 		dma_release_channel(sport->dma_chan_tx);
1029 		sport->dma_chan_tx = NULL;
1030 	}
1031 
1032 	sport->dma_is_inited = 0;
1033 }
1034 
1035 static int imx_uart_dma_init(struct imx_port *sport)
1036 {
1037 	struct dma_slave_config slave_config = {};
1038 	struct device *dev = sport->port.dev;
1039 	int ret;
1040 
1041 	/* Prepare for RX : */
1042 	sport->dma_chan_rx = dma_request_slave_channel(dev, "rx");
1043 	if (!sport->dma_chan_rx) {
1044 		dev_dbg(dev, "cannot get the DMA channel.\n");
1045 		ret = -EINVAL;
1046 		goto err;
1047 	}
1048 
1049 	slave_config.direction = DMA_DEV_TO_MEM;
1050 	slave_config.src_addr = sport->port.mapbase + URXD0;
1051 	slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1052 	slave_config.src_maxburst = RXTL;
1053 	ret = dmaengine_slave_config(sport->dma_chan_rx, &slave_config);
1054 	if (ret) {
1055 		dev_err(dev, "error in RX dma configuration.\n");
1056 		goto err;
1057 	}
1058 
1059 	sport->rx_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
1060 	if (!sport->rx_buf) {
1061 		ret = -ENOMEM;
1062 		goto err;
1063 	}
1064 
1065 	/* Prepare for TX : */
1066 	sport->dma_chan_tx = dma_request_slave_channel(dev, "tx");
1067 	if (!sport->dma_chan_tx) {
1068 		dev_err(dev, "cannot get the TX DMA channel!\n");
1069 		ret = -EINVAL;
1070 		goto err;
1071 	}
1072 
1073 	slave_config.direction = DMA_MEM_TO_DEV;
1074 	slave_config.dst_addr = sport->port.mapbase + URTX0;
1075 	slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1076 	slave_config.dst_maxburst = TXTL;
1077 	ret = dmaengine_slave_config(sport->dma_chan_tx, &slave_config);
1078 	if (ret) {
1079 		dev_err(dev, "error in TX dma configuration.");
1080 		goto err;
1081 	}
1082 
1083 	sport->dma_is_inited = 1;
1084 
1085 	return 0;
1086 err:
1087 	imx_uart_dma_exit(sport);
1088 	return ret;
1089 }
1090 
1091 static void imx_enable_dma(struct imx_port *sport)
1092 {
1093 	unsigned long temp;
1094 
1095 	init_waitqueue_head(&sport->dma_wait);
1096 
1097 	/* set UCR1 */
1098 	temp = readl(sport->port.membase + UCR1);
1099 	temp |= UCR1_RDMAEN | UCR1_TDMAEN | UCR1_ATDMAEN |
1100 		/* wait for 32 idle frames for IDDMA interrupt */
1101 		UCR1_ICD_REG(3);
1102 	writel(temp, sport->port.membase + UCR1);
1103 
1104 	/* set UCR4 */
1105 	temp = readl(sport->port.membase + UCR4);
1106 	temp |= UCR4_IDDMAEN;
1107 	writel(temp, sport->port.membase + UCR4);
1108 
1109 	sport->dma_is_enabled = 1;
1110 }
1111 
1112 static void imx_disable_dma(struct imx_port *sport)
1113 {
1114 	unsigned long temp;
1115 
1116 	/* clear UCR1 */
1117 	temp = readl(sport->port.membase + UCR1);
1118 	temp &= ~(UCR1_RDMAEN | UCR1_TDMAEN | UCR1_ATDMAEN);
1119 	writel(temp, sport->port.membase + UCR1);
1120 
1121 	/* clear UCR2 */
1122 	temp = readl(sport->port.membase + UCR2);
1123 	temp &= ~(UCR2_CTSC | UCR2_CTS);
1124 	writel(temp, sport->port.membase + UCR2);
1125 
1126 	/* clear UCR4 */
1127 	temp = readl(sport->port.membase + UCR4);
1128 	temp &= ~UCR4_IDDMAEN;
1129 	writel(temp, sport->port.membase + UCR4);
1130 
1131 	sport->dma_is_enabled = 0;
1132 }
1133 
1134 /* half the RX buffer size */
1135 #define CTSTL 16
1136 
1137 static int imx_startup(struct uart_port *port)
1138 {
1139 	struct imx_port *sport = (struct imx_port *)port;
1140 	int retval, i;
1141 	unsigned long flags, temp;
1142 
1143 	retval = clk_prepare_enable(sport->clk_per);
1144 	if (retval)
1145 		return retval;
1146 	retval = clk_prepare_enable(sport->clk_ipg);
1147 	if (retval) {
1148 		clk_disable_unprepare(sport->clk_per);
1149 		return retval;
1150 	}
1151 
1152 	imx_setup_ufcr(sport, 0);
1153 
1154 	/* disable the DREN bit (Data Ready interrupt enable) before
1155 	 * requesting IRQs
1156 	 */
1157 	temp = readl(sport->port.membase + UCR4);
1158 
1159 	if (USE_IRDA(sport))
1160 		temp |= UCR4_IRSC;
1161 
1162 	/* set the trigger level for CTS */
1163 	temp &= ~(UCR4_CTSTL_MASK << UCR4_CTSTL_SHF);
1164 	temp |= CTSTL << UCR4_CTSTL_SHF;
1165 
1166 	writel(temp & ~UCR4_DREN, sport->port.membase + UCR4);
1167 
1168 	/* Reset fifo's and state machines */
1169 	i = 100;
1170 
1171 	temp = readl(sport->port.membase + UCR2);
1172 	temp &= ~UCR2_SRST;
1173 	writel(temp, sport->port.membase + UCR2);
1174 
1175 	while (!(readl(sport->port.membase + UCR2) & UCR2_SRST) && (--i > 0))
1176 		udelay(1);
1177 
1178 	/* Can we enable the DMA support? */
1179 	if (is_imx6q_uart(sport) && !uart_console(port) &&
1180 	    !sport->dma_is_inited)
1181 		imx_uart_dma_init(sport);
1182 
1183 	spin_lock_irqsave(&sport->port.lock, flags);
1184 	/*
1185 	 * Finally, clear and enable interrupts
1186 	 */
1187 	writel(USR1_RTSD, sport->port.membase + USR1);
1188 
1189 	if (sport->dma_is_inited && !sport->dma_is_enabled)
1190 		imx_enable_dma(sport);
1191 
1192 	temp = readl(sport->port.membase + UCR1);
1193 	temp |= UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN;
1194 
1195 	if (USE_IRDA(sport)) {
1196 		temp |= UCR1_IREN;
1197 		temp &= ~(UCR1_RTSDEN);
1198 	}
1199 
1200 	writel(temp, sport->port.membase + UCR1);
1201 
1202 	/* Clear any pending ORE flag before enabling interrupt */
1203 	temp = readl(sport->port.membase + USR2);
1204 	writel(temp | USR2_ORE, sport->port.membase + USR2);
1205 
1206 	temp = readl(sport->port.membase + UCR4);
1207 	temp |= UCR4_OREN;
1208 	writel(temp, sport->port.membase + UCR4);
1209 
1210 	temp = readl(sport->port.membase + UCR2);
1211 	temp |= (UCR2_RXEN | UCR2_TXEN);
1212 	if (!sport->have_rtscts)
1213 		temp |= UCR2_IRTS;
1214 	writel(temp, sport->port.membase + UCR2);
1215 
1216 	if (!is_imx1_uart(sport)) {
1217 		temp = readl(sport->port.membase + UCR3);
1218 		temp |= IMX21_UCR3_RXDMUXSEL | UCR3_ADNIMP;
1219 		writel(temp, sport->port.membase + UCR3);
1220 	}
1221 
1222 	if (USE_IRDA(sport)) {
1223 		temp = readl(sport->port.membase + UCR4);
1224 		if (sport->irda_inv_rx)
1225 			temp |= UCR4_INVR;
1226 		else
1227 			temp &= ~(UCR4_INVR);
1228 		writel(temp | UCR4_DREN, sport->port.membase + UCR4);
1229 
1230 		temp = readl(sport->port.membase + UCR3);
1231 		if (sport->irda_inv_tx)
1232 			temp |= UCR3_INVT;
1233 		else
1234 			temp &= ~(UCR3_INVT);
1235 		writel(temp, sport->port.membase + UCR3);
1236 	}
1237 
1238 	/*
1239 	 * Enable modem status interrupts
1240 	 */
1241 	imx_enable_ms(&sport->port);
1242 	spin_unlock_irqrestore(&sport->port.lock, flags);
1243 
1244 	if (USE_IRDA(sport)) {
1245 		struct imxuart_platform_data *pdata;
1246 		pdata = dev_get_platdata(sport->port.dev);
1247 		sport->irda_inv_rx = pdata->irda_inv_rx;
1248 		sport->irda_inv_tx = pdata->irda_inv_tx;
1249 		sport->trcv_delay = pdata->transceiver_delay;
1250 		if (pdata->irda_enable)
1251 			pdata->irda_enable(1);
1252 	}
1253 
1254 	return 0;
1255 }
1256 
1257 static void imx_shutdown(struct uart_port *port)
1258 {
1259 	struct imx_port *sport = (struct imx_port *)port;
1260 	unsigned long temp;
1261 	unsigned long flags;
1262 
1263 	if (sport->dma_is_enabled) {
1264 		int ret;
1265 
1266 		/* We have to wait for the DMA to finish. */
1267 		ret = wait_event_interruptible(sport->dma_wait,
1268 			!sport->dma_is_rxing && !sport->dma_is_txing);
1269 		if (ret != 0) {
1270 			sport->dma_is_rxing = 0;
1271 			sport->dma_is_txing = 0;
1272 			dmaengine_terminate_all(sport->dma_chan_tx);
1273 			dmaengine_terminate_all(sport->dma_chan_rx);
1274 		}
1275 		spin_lock_irqsave(&sport->port.lock, flags);
1276 		imx_stop_tx(port);
1277 		imx_stop_rx(port);
1278 		imx_disable_dma(sport);
1279 		spin_unlock_irqrestore(&sport->port.lock, flags);
1280 		imx_uart_dma_exit(sport);
1281 	}
1282 
1283 	spin_lock_irqsave(&sport->port.lock, flags);
1284 	temp = readl(sport->port.membase + UCR2);
1285 	temp &= ~(UCR2_TXEN);
1286 	writel(temp, sport->port.membase + UCR2);
1287 	spin_unlock_irqrestore(&sport->port.lock, flags);
1288 
1289 	if (USE_IRDA(sport)) {
1290 		struct imxuart_platform_data *pdata;
1291 		pdata = dev_get_platdata(sport->port.dev);
1292 		if (pdata->irda_enable)
1293 			pdata->irda_enable(0);
1294 	}
1295 
1296 	/*
1297 	 * Stop our timer.
1298 	 */
1299 	del_timer_sync(&sport->timer);
1300 
1301 	/*
1302 	 * Disable all interrupts, port and break condition.
1303 	 */
1304 
1305 	spin_lock_irqsave(&sport->port.lock, flags);
1306 	temp = readl(sport->port.membase + UCR1);
1307 	temp &= ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN);
1308 	if (USE_IRDA(sport))
1309 		temp &= ~(UCR1_IREN);
1310 
1311 	writel(temp, sport->port.membase + UCR1);
1312 	spin_unlock_irqrestore(&sport->port.lock, flags);
1313 
1314 	clk_disable_unprepare(sport->clk_per);
1315 	clk_disable_unprepare(sport->clk_ipg);
1316 }
1317 
1318 static void imx_flush_buffer(struct uart_port *port)
1319 {
1320 	struct imx_port *sport = (struct imx_port *)port;
1321 	struct scatterlist *sgl = &sport->tx_sgl[0];
1322 	unsigned long temp;
1323 	int i = 100, ubir, ubmr, ubrc, uts;
1324 
1325 	if (!sport->dma_chan_tx)
1326 		return;
1327 
1328 	sport->tx_bytes = 0;
1329 	dmaengine_terminate_all(sport->dma_chan_tx);
1330 	if (sport->dma_is_txing) {
1331 		dma_unmap_sg(sport->port.dev, sgl, sport->dma_tx_nents,
1332 			     DMA_TO_DEVICE);
1333 		temp = readl(sport->port.membase + UCR1);
1334 		temp &= ~UCR1_TDMAEN;
1335 		writel(temp, sport->port.membase + UCR1);
1336 		sport->dma_is_txing = false;
1337 	}
1338 
1339 	/*
1340 	 * According to the Reference Manual description of the UART SRST bit:
1341 	 * "Reset the transmit and receive state machines,
1342 	 * all FIFOs and register USR1, USR2, UBIR, UBMR, UBRC, URXD, UTXD
1343 	 * and UTS[6-3]". As we don't need to restore the old values from
1344 	 * USR1, USR2, URXD, UTXD, only save/restore the other four registers
1345 	 */
1346 	ubir = readl(sport->port.membase + UBIR);
1347 	ubmr = readl(sport->port.membase + UBMR);
1348 	ubrc = readl(sport->port.membase + UBRC);
1349 	uts = readl(sport->port.membase + IMX21_UTS);
1350 
1351 	temp = readl(sport->port.membase + UCR2);
1352 	temp &= ~UCR2_SRST;
1353 	writel(temp, sport->port.membase + UCR2);
1354 
1355 	while (!(readl(sport->port.membase + UCR2) & UCR2_SRST) && (--i > 0))
1356 		udelay(1);
1357 
1358 	/* Restore the registers */
1359 	writel(ubir, sport->port.membase + UBIR);
1360 	writel(ubmr, sport->port.membase + UBMR);
1361 	writel(ubrc, sport->port.membase + UBRC);
1362 	writel(uts, sport->port.membase + IMX21_UTS);
1363 }
1364 
1365 static void
1366 imx_set_termios(struct uart_port *port, struct ktermios *termios,
1367 		   struct ktermios *old)
1368 {
1369 	struct imx_port *sport = (struct imx_port *)port;
1370 	unsigned long flags;
1371 	unsigned int ucr2, old_ucr1, old_txrxen, baud, quot;
1372 	unsigned int old_csize = old ? old->c_cflag & CSIZE : CS8;
1373 	unsigned int div, ufcr;
1374 	unsigned long num, denom;
1375 	uint64_t tdiv64;
1376 
1377 	/*
1378 	 * If we don't support modem control lines, don't allow
1379 	 * these to be set.
1380 	 */
1381 	if (0) {
1382 		termios->c_cflag &= ~(HUPCL | CRTSCTS | CMSPAR);
1383 		termios->c_cflag |= CLOCAL;
1384 	}
1385 
1386 	/*
1387 	 * We only support CS7 and CS8.
1388 	 */
1389 	while ((termios->c_cflag & CSIZE) != CS7 &&
1390 	       (termios->c_cflag & CSIZE) != CS8) {
1391 		termios->c_cflag &= ~CSIZE;
1392 		termios->c_cflag |= old_csize;
1393 		old_csize = CS8;
1394 	}
1395 
1396 	if ((termios->c_cflag & CSIZE) == CS8)
1397 		ucr2 = UCR2_WS | UCR2_SRST | UCR2_IRTS;
1398 	else
1399 		ucr2 = UCR2_SRST | UCR2_IRTS;
1400 
1401 	if (termios->c_cflag & CRTSCTS) {
1402 		if (sport->have_rtscts) {
1403 			ucr2 &= ~UCR2_IRTS;
1404 			ucr2 |= UCR2_CTSC;
1405 		} else {
1406 			termios->c_cflag &= ~CRTSCTS;
1407 		}
1408 	}
1409 
1410 	if (termios->c_cflag & CSTOPB)
1411 		ucr2 |= UCR2_STPB;
1412 	if (termios->c_cflag & PARENB) {
1413 		ucr2 |= UCR2_PREN;
1414 		if (termios->c_cflag & PARODD)
1415 			ucr2 |= UCR2_PROE;
1416 	}
1417 
1418 	del_timer_sync(&sport->timer);
1419 
1420 	/*
1421 	 * Ask the core to calculate the divisor for us.
1422 	 */
1423 	baud = uart_get_baud_rate(port, termios, old, 50, port->uartclk / 16);
1424 	quot = uart_get_divisor(port, baud);
1425 
1426 	spin_lock_irqsave(&sport->port.lock, flags);
1427 
1428 	sport->port.read_status_mask = 0;
1429 	if (termios->c_iflag & INPCK)
1430 		sport->port.read_status_mask |= (URXD_FRMERR | URXD_PRERR);
1431 	if (termios->c_iflag & (BRKINT | PARMRK))
1432 		sport->port.read_status_mask |= URXD_BRK;
1433 
1434 	/*
1435 	 * Characters to ignore
1436 	 */
1437 	sport->port.ignore_status_mask = 0;
1438 	if (termios->c_iflag & IGNPAR)
1439 		sport->port.ignore_status_mask |= URXD_PRERR | URXD_FRMERR;
1440 	if (termios->c_iflag & IGNBRK) {
1441 		sport->port.ignore_status_mask |= URXD_BRK;
1442 		/*
1443 		 * If we're ignoring parity and break indicators,
1444 		 * ignore overruns too (for real raw support).
1445 		 */
1446 		if (termios->c_iflag & IGNPAR)
1447 			sport->port.ignore_status_mask |= URXD_OVRRUN;
1448 	}
1449 
1450 	if ((termios->c_cflag & CREAD) == 0)
1451 		sport->port.ignore_status_mask |= URXD_DUMMY_READ;
1452 
1453 	/*
1454 	 * Update the per-port timeout.
1455 	 */
1456 	uart_update_timeout(port, termios->c_cflag, baud);
1457 
1458 	/*
1459 	 * disable interrupts and drain transmitter
1460 	 */
1461 	old_ucr1 = readl(sport->port.membase + UCR1);
1462 	writel(old_ucr1 & ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN),
1463 			sport->port.membase + UCR1);
1464 
1465 	while (!(readl(sport->port.membase + USR2) & USR2_TXDC))
1466 		barrier();
1467 
1468 	/* then, disable everything */
1469 	old_txrxen = readl(sport->port.membase + UCR2);
1470 	writel(old_txrxen & ~(UCR2_TXEN | UCR2_RXEN),
1471 			sport->port.membase + UCR2);
1472 	old_txrxen &= (UCR2_TXEN | UCR2_RXEN);
1473 
1474 	if (USE_IRDA(sport)) {
1475 		/*
1476 		 * use maximum available submodule frequency to
1477 		 * avoid missing short pulses due to low sampling rate
1478 		 */
1479 		div = 1;
1480 	} else {
1481 		/* custom-baudrate handling */
1482 		div = sport->port.uartclk / (baud * 16);
1483 		if (baud == 38400 && quot != div)
1484 			baud = sport->port.uartclk / (quot * 16);
1485 
1486 		div = sport->port.uartclk / (baud * 16);
1487 		if (div > 7)
1488 			div = 7;
1489 		if (!div)
1490 			div = 1;
1491 	}
1492 
1493 	rational_best_approximation(16 * div * baud, sport->port.uartclk,
1494 		1 << 16, 1 << 16, &num, &denom);
1495 
1496 	tdiv64 = sport->port.uartclk;
1497 	tdiv64 *= num;
1498 	do_div(tdiv64, denom * 16 * div);
1499 	tty_termios_encode_baud_rate(termios,
1500 				(speed_t)tdiv64, (speed_t)tdiv64);
1501 
1502 	num -= 1;
1503 	denom -= 1;
1504 
1505 	ufcr = readl(sport->port.membase + UFCR);
1506 	ufcr = (ufcr & (~UFCR_RFDIV)) | UFCR_RFDIV_REG(div);
1507 	if (sport->dte_mode)
1508 		ufcr |= UFCR_DCEDTE;
1509 	writel(ufcr, sport->port.membase + UFCR);
1510 
1511 	writel(num, sport->port.membase + UBIR);
1512 	writel(denom, sport->port.membase + UBMR);
1513 
1514 	if (!is_imx1_uart(sport))
1515 		writel(sport->port.uartclk / div / 1000,
1516 				sport->port.membase + IMX21_ONEMS);
1517 
1518 	writel(old_ucr1, sport->port.membase + UCR1);
1519 
1520 	/* set the parity, stop bits and data size */
1521 	writel(ucr2 | old_txrxen, sport->port.membase + UCR2);
1522 
1523 	if (UART_ENABLE_MS(&sport->port, termios->c_cflag))
1524 		imx_enable_ms(&sport->port);
1525 
1526 	spin_unlock_irqrestore(&sport->port.lock, flags);
1527 }
1528 
1529 static const char *imx_type(struct uart_port *port)
1530 {
1531 	struct imx_port *sport = (struct imx_port *)port;
1532 
1533 	return sport->port.type == PORT_IMX ? "IMX" : NULL;
1534 }
1535 
1536 /*
1537  * Configure/autoconfigure the port.
1538  */
1539 static void imx_config_port(struct uart_port *port, int flags)
1540 {
1541 	struct imx_port *sport = (struct imx_port *)port;
1542 
1543 	if (flags & UART_CONFIG_TYPE)
1544 		sport->port.type = PORT_IMX;
1545 }
1546 
1547 /*
1548  * Verify the new serial_struct (for TIOCSSERIAL).
1549  * The only change we allow are to the flags and type, and
1550  * even then only between PORT_IMX and PORT_UNKNOWN
1551  */
1552 static int
1553 imx_verify_port(struct uart_port *port, struct serial_struct *ser)
1554 {
1555 	struct imx_port *sport = (struct imx_port *)port;
1556 	int ret = 0;
1557 
1558 	if (ser->type != PORT_UNKNOWN && ser->type != PORT_IMX)
1559 		ret = -EINVAL;
1560 	if (sport->port.irq != ser->irq)
1561 		ret = -EINVAL;
1562 	if (ser->io_type != UPIO_MEM)
1563 		ret = -EINVAL;
1564 	if (sport->port.uartclk / 16 != ser->baud_base)
1565 		ret = -EINVAL;
1566 	if (sport->port.mapbase != (unsigned long)ser->iomem_base)
1567 		ret = -EINVAL;
1568 	if (sport->port.iobase != ser->port)
1569 		ret = -EINVAL;
1570 	if (ser->hub6 != 0)
1571 		ret = -EINVAL;
1572 	return ret;
1573 }
1574 
1575 #if defined(CONFIG_CONSOLE_POLL)
1576 
1577 static int imx_poll_init(struct uart_port *port)
1578 {
1579 	struct imx_port *sport = (struct imx_port *)port;
1580 	unsigned long flags;
1581 	unsigned long temp;
1582 	int retval;
1583 
1584 	retval = clk_prepare_enable(sport->clk_ipg);
1585 	if (retval)
1586 		return retval;
1587 	retval = clk_prepare_enable(sport->clk_per);
1588 	if (retval)
1589 		clk_disable_unprepare(sport->clk_ipg);
1590 
1591 	imx_setup_ufcr(sport, 0);
1592 
1593 	spin_lock_irqsave(&sport->port.lock, flags);
1594 
1595 	temp = readl(sport->port.membase + UCR1);
1596 	if (is_imx1_uart(sport))
1597 		temp |= IMX1_UCR1_UARTCLKEN;
1598 	temp |= UCR1_UARTEN | UCR1_RRDYEN;
1599 	temp &= ~(UCR1_TXMPTYEN | UCR1_RTSDEN);
1600 	writel(temp, sport->port.membase + UCR1);
1601 
1602 	temp = readl(sport->port.membase + UCR2);
1603 	temp |= UCR2_RXEN;
1604 	writel(temp, sport->port.membase + UCR2);
1605 
1606 	spin_unlock_irqrestore(&sport->port.lock, flags);
1607 
1608 	return 0;
1609 }
1610 
1611 static int imx_poll_get_char(struct uart_port *port)
1612 {
1613 	if (!(readl_relaxed(port->membase + USR2) & USR2_RDR))
1614 		return NO_POLL_CHAR;
1615 
1616 	return readl_relaxed(port->membase + URXD0) & URXD_RX_DATA;
1617 }
1618 
1619 static void imx_poll_put_char(struct uart_port *port, unsigned char c)
1620 {
1621 	unsigned int status;
1622 
1623 	/* drain */
1624 	do {
1625 		status = readl_relaxed(port->membase + USR1);
1626 	} while (~status & USR1_TRDY);
1627 
1628 	/* write */
1629 	writel_relaxed(c, port->membase + URTX0);
1630 
1631 	/* flush */
1632 	do {
1633 		status = readl_relaxed(port->membase + USR2);
1634 	} while (~status & USR2_TXDC);
1635 }
1636 #endif
1637 
1638 static struct uart_ops imx_pops = {
1639 	.tx_empty	= imx_tx_empty,
1640 	.set_mctrl	= imx_set_mctrl,
1641 	.get_mctrl	= imx_get_mctrl,
1642 	.stop_tx	= imx_stop_tx,
1643 	.start_tx	= imx_start_tx,
1644 	.stop_rx	= imx_stop_rx,
1645 	.enable_ms	= imx_enable_ms,
1646 	.break_ctl	= imx_break_ctl,
1647 	.startup	= imx_startup,
1648 	.shutdown	= imx_shutdown,
1649 	.flush_buffer	= imx_flush_buffer,
1650 	.set_termios	= imx_set_termios,
1651 	.type		= imx_type,
1652 	.config_port	= imx_config_port,
1653 	.verify_port	= imx_verify_port,
1654 #if defined(CONFIG_CONSOLE_POLL)
1655 	.poll_init      = imx_poll_init,
1656 	.poll_get_char  = imx_poll_get_char,
1657 	.poll_put_char  = imx_poll_put_char,
1658 #endif
1659 };
1660 
1661 static struct imx_port *imx_ports[UART_NR];
1662 
1663 #ifdef CONFIG_SERIAL_IMX_CONSOLE
1664 static void imx_console_putchar(struct uart_port *port, int ch)
1665 {
1666 	struct imx_port *sport = (struct imx_port *)port;
1667 
1668 	while (readl(sport->port.membase + uts_reg(sport)) & UTS_TXFULL)
1669 		barrier();
1670 
1671 	writel(ch, sport->port.membase + URTX0);
1672 }
1673 
1674 /*
1675  * Interrupts are disabled on entering
1676  */
1677 static void
1678 imx_console_write(struct console *co, const char *s, unsigned int count)
1679 {
1680 	struct imx_port *sport = imx_ports[co->index];
1681 	struct imx_port_ucrs old_ucr;
1682 	unsigned int ucr1;
1683 	unsigned long flags = 0;
1684 	int locked = 1;
1685 	int retval;
1686 
1687 	retval = clk_enable(sport->clk_per);
1688 	if (retval)
1689 		return;
1690 	retval = clk_enable(sport->clk_ipg);
1691 	if (retval) {
1692 		clk_disable(sport->clk_per);
1693 		return;
1694 	}
1695 
1696 	if (sport->port.sysrq)
1697 		locked = 0;
1698 	else if (oops_in_progress)
1699 		locked = spin_trylock_irqsave(&sport->port.lock, flags);
1700 	else
1701 		spin_lock_irqsave(&sport->port.lock, flags);
1702 
1703 	/*
1704 	 *	First, save UCR1/2/3 and then disable interrupts
1705 	 */
1706 	imx_port_ucrs_save(&sport->port, &old_ucr);
1707 	ucr1 = old_ucr.ucr1;
1708 
1709 	if (is_imx1_uart(sport))
1710 		ucr1 |= IMX1_UCR1_UARTCLKEN;
1711 	ucr1 |= UCR1_UARTEN;
1712 	ucr1 &= ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN);
1713 
1714 	writel(ucr1, sport->port.membase + UCR1);
1715 
1716 	writel(old_ucr.ucr2 | UCR2_TXEN, sport->port.membase + UCR2);
1717 
1718 	uart_console_write(&sport->port, s, count, imx_console_putchar);
1719 
1720 	/*
1721 	 *	Finally, wait for transmitter to become empty
1722 	 *	and restore UCR1/2/3
1723 	 */
1724 	while (!(readl(sport->port.membase + USR2) & USR2_TXDC));
1725 
1726 	imx_port_ucrs_restore(&sport->port, &old_ucr);
1727 
1728 	if (locked)
1729 		spin_unlock_irqrestore(&sport->port.lock, flags);
1730 
1731 	clk_disable(sport->clk_ipg);
1732 	clk_disable(sport->clk_per);
1733 }
1734 
1735 /*
1736  * If the port was already initialised (eg, by a boot loader),
1737  * try to determine the current setup.
1738  */
1739 static void __init
1740 imx_console_get_options(struct imx_port *sport, int *baud,
1741 			   int *parity, int *bits)
1742 {
1743 
1744 	if (readl(sport->port.membase + UCR1) & UCR1_UARTEN) {
1745 		/* ok, the port was enabled */
1746 		unsigned int ucr2, ubir, ubmr, uartclk;
1747 		unsigned int baud_raw;
1748 		unsigned int ucfr_rfdiv;
1749 
1750 		ucr2 = readl(sport->port.membase + UCR2);
1751 
1752 		*parity = 'n';
1753 		if (ucr2 & UCR2_PREN) {
1754 			if (ucr2 & UCR2_PROE)
1755 				*parity = 'o';
1756 			else
1757 				*parity = 'e';
1758 		}
1759 
1760 		if (ucr2 & UCR2_WS)
1761 			*bits = 8;
1762 		else
1763 			*bits = 7;
1764 
1765 		ubir = readl(sport->port.membase + UBIR) & 0xffff;
1766 		ubmr = readl(sport->port.membase + UBMR) & 0xffff;
1767 
1768 		ucfr_rfdiv = (readl(sport->port.membase + UFCR) & UFCR_RFDIV) >> 7;
1769 		if (ucfr_rfdiv == 6)
1770 			ucfr_rfdiv = 7;
1771 		else
1772 			ucfr_rfdiv = 6 - ucfr_rfdiv;
1773 
1774 		uartclk = clk_get_rate(sport->clk_per);
1775 		uartclk /= ucfr_rfdiv;
1776 
1777 		{	/*
1778 			 * The next code provides exact computation of
1779 			 *   baud_raw = round(((uartclk/16) * (ubir + 1)) / (ubmr + 1))
1780 			 * without need of float support or long long division,
1781 			 * which would be required to prevent 32bit arithmetic overflow
1782 			 */
1783 			unsigned int mul = ubir + 1;
1784 			unsigned int div = 16 * (ubmr + 1);
1785 			unsigned int rem = uartclk % div;
1786 
1787 			baud_raw = (uartclk / div) * mul;
1788 			baud_raw += (rem * mul + div / 2) / div;
1789 			*baud = (baud_raw + 50) / 100 * 100;
1790 		}
1791 
1792 		if (*baud != baud_raw)
1793 			pr_info("Console IMX rounded baud rate from %d to %d\n",
1794 				baud_raw, *baud);
1795 	}
1796 }
1797 
1798 static int __init
1799 imx_console_setup(struct console *co, char *options)
1800 {
1801 	struct imx_port *sport;
1802 	int baud = 9600;
1803 	int bits = 8;
1804 	int parity = 'n';
1805 	int flow = 'n';
1806 	int retval;
1807 
1808 	/*
1809 	 * Check whether an invalid uart number has been specified, and
1810 	 * if so, search for the first available port that does have
1811 	 * console support.
1812 	 */
1813 	if (co->index == -1 || co->index >= ARRAY_SIZE(imx_ports))
1814 		co->index = 0;
1815 	sport = imx_ports[co->index];
1816 	if (sport == NULL)
1817 		return -ENODEV;
1818 
1819 	/* For setting the registers, we only need to enable the ipg clock. */
1820 	retval = clk_prepare_enable(sport->clk_ipg);
1821 	if (retval)
1822 		goto error_console;
1823 
1824 	if (options)
1825 		uart_parse_options(options, &baud, &parity, &bits, &flow);
1826 	else
1827 		imx_console_get_options(sport, &baud, &parity, &bits);
1828 
1829 	imx_setup_ufcr(sport, 0);
1830 
1831 	retval = uart_set_options(&sport->port, co, baud, parity, bits, flow);
1832 
1833 	clk_disable(sport->clk_ipg);
1834 	if (retval) {
1835 		clk_unprepare(sport->clk_ipg);
1836 		goto error_console;
1837 	}
1838 
1839 	retval = clk_prepare(sport->clk_per);
1840 	if (retval)
1841 		clk_disable_unprepare(sport->clk_ipg);
1842 
1843 error_console:
1844 	return retval;
1845 }
1846 
1847 static struct uart_driver imx_reg;
1848 static struct console imx_console = {
1849 	.name		= DEV_NAME,
1850 	.write		= imx_console_write,
1851 	.device		= uart_console_device,
1852 	.setup		= imx_console_setup,
1853 	.flags		= CON_PRINTBUFFER,
1854 	.index		= -1,
1855 	.data		= &imx_reg,
1856 };
1857 
1858 #define IMX_CONSOLE	&imx_console
1859 #else
1860 #define IMX_CONSOLE	NULL
1861 #endif
1862 
1863 static struct uart_driver imx_reg = {
1864 	.owner          = THIS_MODULE,
1865 	.driver_name    = DRIVER_NAME,
1866 	.dev_name       = DEV_NAME,
1867 	.major          = SERIAL_IMX_MAJOR,
1868 	.minor          = MINOR_START,
1869 	.nr             = ARRAY_SIZE(imx_ports),
1870 	.cons           = IMX_CONSOLE,
1871 };
1872 
1873 static int serial_imx_suspend(struct platform_device *dev, pm_message_t state)
1874 {
1875 	struct imx_port *sport = platform_get_drvdata(dev);
1876 	unsigned int val;
1877 
1878 	/* enable wakeup from i.MX UART */
1879 	val = readl(sport->port.membase + UCR3);
1880 	val |= UCR3_AWAKEN;
1881 	writel(val, sport->port.membase + UCR3);
1882 
1883 	uart_suspend_port(&imx_reg, &sport->port);
1884 
1885 	return 0;
1886 }
1887 
1888 static int serial_imx_resume(struct platform_device *dev)
1889 {
1890 	struct imx_port *sport = platform_get_drvdata(dev);
1891 	unsigned int val;
1892 
1893 	/* disable wakeup from i.MX UART */
1894 	val = readl(sport->port.membase + UCR3);
1895 	val &= ~UCR3_AWAKEN;
1896 	writel(val, sport->port.membase + UCR3);
1897 
1898 	uart_resume_port(&imx_reg, &sport->port);
1899 
1900 	return 0;
1901 }
1902 
1903 #ifdef CONFIG_OF
1904 /*
1905  * This function returns 1 iff pdev isn't a device instatiated by dt, 0 iff it
1906  * could successfully get all information from dt or a negative errno.
1907  */
1908 static int serial_imx_probe_dt(struct imx_port *sport,
1909 		struct platform_device *pdev)
1910 {
1911 	struct device_node *np = pdev->dev.of_node;
1912 	const struct of_device_id *of_id =
1913 			of_match_device(imx_uart_dt_ids, &pdev->dev);
1914 	int ret;
1915 
1916 	if (!np)
1917 		/* no device tree device */
1918 		return 1;
1919 
1920 	ret = of_alias_get_id(np, "serial");
1921 	if (ret < 0) {
1922 		dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
1923 		return ret;
1924 	}
1925 	sport->port.line = ret;
1926 
1927 	if (of_get_property(np, "fsl,uart-has-rtscts", NULL))
1928 		sport->have_rtscts = 1;
1929 
1930 	if (of_get_property(np, "fsl,irda-mode", NULL))
1931 		sport->use_irda = 1;
1932 
1933 	if (of_get_property(np, "fsl,dte-mode", NULL))
1934 		sport->dte_mode = 1;
1935 
1936 	sport->devdata = of_id->data;
1937 
1938 	return 0;
1939 }
1940 #else
1941 static inline int serial_imx_probe_dt(struct imx_port *sport,
1942 		struct platform_device *pdev)
1943 {
1944 	return 1;
1945 }
1946 #endif
1947 
1948 static void serial_imx_probe_pdata(struct imx_port *sport,
1949 		struct platform_device *pdev)
1950 {
1951 	struct imxuart_platform_data *pdata = dev_get_platdata(&pdev->dev);
1952 
1953 	sport->port.line = pdev->id;
1954 	sport->devdata = (struct imx_uart_data	*) pdev->id_entry->driver_data;
1955 
1956 	if (!pdata)
1957 		return;
1958 
1959 	if (pdata->flags & IMXUART_HAVE_RTSCTS)
1960 		sport->have_rtscts = 1;
1961 
1962 	if (pdata->flags & IMXUART_IRDA)
1963 		sport->use_irda = 1;
1964 }
1965 
1966 static int serial_imx_probe(struct platform_device *pdev)
1967 {
1968 	struct imx_port *sport;
1969 	void __iomem *base;
1970 	int ret = 0;
1971 	struct resource *res;
1972 
1973 	sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL);
1974 	if (!sport)
1975 		return -ENOMEM;
1976 
1977 	ret = serial_imx_probe_dt(sport, pdev);
1978 	if (ret > 0)
1979 		serial_imx_probe_pdata(sport, pdev);
1980 	else if (ret < 0)
1981 		return ret;
1982 
1983 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1984 	base = devm_ioremap_resource(&pdev->dev, res);
1985 	if (IS_ERR(base))
1986 		return PTR_ERR(base);
1987 
1988 	sport->port.dev = &pdev->dev;
1989 	sport->port.mapbase = res->start;
1990 	sport->port.membase = base;
1991 	sport->port.type = PORT_IMX,
1992 	sport->port.iotype = UPIO_MEM;
1993 	sport->port.irq = platform_get_irq(pdev, 0);
1994 	sport->rxirq = platform_get_irq(pdev, 0);
1995 	sport->txirq = platform_get_irq(pdev, 1);
1996 	sport->rtsirq = platform_get_irq(pdev, 2);
1997 	sport->port.fifosize = 32;
1998 	sport->port.ops = &imx_pops;
1999 	sport->port.flags = UPF_BOOT_AUTOCONF;
2000 	init_timer(&sport->timer);
2001 	sport->timer.function = imx_timeout;
2002 	sport->timer.data     = (unsigned long)sport;
2003 
2004 	sport->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
2005 	if (IS_ERR(sport->clk_ipg)) {
2006 		ret = PTR_ERR(sport->clk_ipg);
2007 		dev_err(&pdev->dev, "failed to get ipg clk: %d\n", ret);
2008 		return ret;
2009 	}
2010 
2011 	sport->clk_per = devm_clk_get(&pdev->dev, "per");
2012 	if (IS_ERR(sport->clk_per)) {
2013 		ret = PTR_ERR(sport->clk_per);
2014 		dev_err(&pdev->dev, "failed to get per clk: %d\n", ret);
2015 		return ret;
2016 	}
2017 
2018 	sport->port.uartclk = clk_get_rate(sport->clk_per);
2019 
2020 	/*
2021 	 * Allocate the IRQ(s) i.MX1 has three interrupts whereas later
2022 	 * chips only have one interrupt.
2023 	 */
2024 	if (sport->txirq > 0) {
2025 		ret = devm_request_irq(&pdev->dev, sport->rxirq, imx_rxint, 0,
2026 				       dev_name(&pdev->dev), sport);
2027 		if (ret)
2028 			return ret;
2029 
2030 		ret = devm_request_irq(&pdev->dev, sport->txirq, imx_txint, 0,
2031 				       dev_name(&pdev->dev), sport);
2032 		if (ret)
2033 			return ret;
2034 
2035 		/* do not use RTS IRQ on IrDA */
2036 		if (!USE_IRDA(sport)) {
2037 			ret = devm_request_irq(&pdev->dev, sport->rtsirq,
2038 					       imx_rtsint, 0,
2039 					       dev_name(&pdev->dev), sport);
2040 			if (ret)
2041 				return ret;
2042 		}
2043 	} else {
2044 		ret = devm_request_irq(&pdev->dev, sport->port.irq, imx_int, 0,
2045 				       dev_name(&pdev->dev), sport);
2046 		if (ret)
2047 			return ret;
2048 	}
2049 
2050 	imx_ports[sport->port.line] = sport;
2051 
2052 	platform_set_drvdata(pdev, sport);
2053 
2054 	return uart_add_one_port(&imx_reg, &sport->port);
2055 }
2056 
2057 static int serial_imx_remove(struct platform_device *pdev)
2058 {
2059 	struct imx_port *sport = platform_get_drvdata(pdev);
2060 
2061 	return uart_remove_one_port(&imx_reg, &sport->port);
2062 }
2063 
2064 static struct platform_driver serial_imx_driver = {
2065 	.probe		= serial_imx_probe,
2066 	.remove		= serial_imx_remove,
2067 
2068 	.suspend	= serial_imx_suspend,
2069 	.resume		= serial_imx_resume,
2070 	.id_table	= imx_uart_devtype,
2071 	.driver		= {
2072 		.name	= "imx-uart",
2073 		.of_match_table = imx_uart_dt_ids,
2074 	},
2075 };
2076 
2077 static int __init imx_serial_init(void)
2078 {
2079 	int ret = uart_register_driver(&imx_reg);
2080 
2081 	if (ret)
2082 		return ret;
2083 
2084 	ret = platform_driver_register(&serial_imx_driver);
2085 	if (ret != 0)
2086 		uart_unregister_driver(&imx_reg);
2087 
2088 	return ret;
2089 }
2090 
2091 static void __exit imx_serial_exit(void)
2092 {
2093 	platform_driver_unregister(&serial_imx_driver);
2094 	uart_unregister_driver(&imx_reg);
2095 }
2096 
2097 module_init(imx_serial_init);
2098 module_exit(imx_serial_exit);
2099 
2100 MODULE_AUTHOR("Sascha Hauer");
2101 MODULE_DESCRIPTION("IMX generic serial port driver");
2102 MODULE_LICENSE("GPL");
2103 MODULE_ALIAS("platform:imx-uart");
2104