xref: /openbmc/linux/drivers/tty/serial/imx.c (revision 95e9fd10)
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/pinctrl/consumer.h>
51 
52 #include <asm/io.h>
53 #include <asm/irq.h>
54 #include <mach/imx-uart.h>
55 
56 /* Register definitions */
57 #define URXD0 0x0  /* Receiver Register */
58 #define URTX0 0x40 /* Transmitter Register */
59 #define UCR1  0x80 /* Control Register 1 */
60 #define UCR2  0x84 /* Control Register 2 */
61 #define UCR3  0x88 /* Control Register 3 */
62 #define UCR4  0x8c /* Control Register 4 */
63 #define UFCR  0x90 /* FIFO Control Register */
64 #define USR1  0x94 /* Status Register 1 */
65 #define USR2  0x98 /* Status Register 2 */
66 #define UESC  0x9c /* Escape Character Register */
67 #define UTIM  0xa0 /* Escape Timer Register */
68 #define UBIR  0xa4 /* BRM Incremental Register */
69 #define UBMR  0xa8 /* BRM Modulator Register */
70 #define UBRC  0xac /* Baud Rate Count Register */
71 #define IMX21_ONEMS 0xb0 /* One Millisecond register */
72 #define IMX1_UTS 0xd0 /* UART Test Register on i.mx1 */
73 #define IMX21_UTS 0xb4 /* UART Test Register on all other i.mx*/
74 
75 /* UART Control Register Bit Fields.*/
76 #define  URXD_CHARRDY    (1<<15)
77 #define  URXD_ERR        (1<<14)
78 #define  URXD_OVRRUN     (1<<13)
79 #define  URXD_FRMERR     (1<<12)
80 #define  URXD_BRK        (1<<11)
81 #define  URXD_PRERR      (1<<10)
82 #define  UCR1_ADEN       (1<<15) /* Auto detect interrupt */
83 #define  UCR1_ADBR       (1<<14) /* Auto detect baud rate */
84 #define  UCR1_TRDYEN     (1<<13) /* Transmitter ready interrupt enable */
85 #define  UCR1_IDEN       (1<<12) /* Idle condition interrupt */
86 #define  UCR1_RRDYEN     (1<<9)	 /* Recv ready interrupt enable */
87 #define  UCR1_RDMAEN     (1<<8)	 /* Recv ready DMA enable */
88 #define  UCR1_IREN       (1<<7)	 /* Infrared interface enable */
89 #define  UCR1_TXMPTYEN   (1<<6)	 /* Transimitter empty interrupt enable */
90 #define  UCR1_RTSDEN     (1<<5)	 /* RTS delta interrupt enable */
91 #define  UCR1_SNDBRK     (1<<4)	 /* Send break */
92 #define  UCR1_TDMAEN     (1<<3)	 /* Transmitter ready DMA enable */
93 #define  IMX1_UCR1_UARTCLKEN  (1<<2)  /* UART clock enabled, i.mx1 only */
94 #define  UCR1_DOZE       (1<<1)	 /* Doze */
95 #define  UCR1_UARTEN     (1<<0)	 /* UART enabled */
96 #define  UCR2_ESCI     	 (1<<15) /* Escape seq interrupt enable */
97 #define  UCR2_IRTS  	 (1<<14) /* Ignore RTS pin */
98 #define  UCR2_CTSC  	 (1<<13) /* CTS pin control */
99 #define  UCR2_CTS        (1<<12) /* Clear to send */
100 #define  UCR2_ESCEN      (1<<11) /* Escape enable */
101 #define  UCR2_PREN       (1<<8)  /* Parity enable */
102 #define  UCR2_PROE       (1<<7)  /* Parity odd/even */
103 #define  UCR2_STPB       (1<<6)	 /* Stop */
104 #define  UCR2_WS         (1<<5)	 /* Word size */
105 #define  UCR2_RTSEN      (1<<4)	 /* Request to send interrupt enable */
106 #define  UCR2_ATEN       (1<<3)  /* Aging Timer Enable */
107 #define  UCR2_TXEN       (1<<2)	 /* Transmitter enabled */
108 #define  UCR2_RXEN       (1<<1)	 /* Receiver enabled */
109 #define  UCR2_SRST 	 (1<<0)	 /* SW reset */
110 #define  UCR3_DTREN 	 (1<<13) /* DTR interrupt enable */
111 #define  UCR3_PARERREN   (1<<12) /* Parity enable */
112 #define  UCR3_FRAERREN   (1<<11) /* Frame error interrupt enable */
113 #define  UCR3_DSR        (1<<10) /* Data set ready */
114 #define  UCR3_DCD        (1<<9)  /* Data carrier detect */
115 #define  UCR3_RI         (1<<8)  /* Ring indicator */
116 #define  UCR3_TIMEOUTEN  (1<<7)  /* Timeout interrupt enable */
117 #define  UCR3_RXDSEN	 (1<<6)  /* Receive status interrupt enable */
118 #define  UCR3_AIRINTEN   (1<<5)  /* Async IR wake interrupt enable */
119 #define  UCR3_AWAKEN	 (1<<4)  /* Async wake interrupt enable */
120 #define  IMX21_UCR3_RXDMUXSEL	 (1<<2)  /* RXD Muxed Input Select */
121 #define  UCR3_INVT  	 (1<<1)  /* Inverted Infrared transmission */
122 #define  UCR3_BPEN  	 (1<<0)  /* Preset registers enable */
123 #define  UCR4_CTSTL_SHF  10      /* CTS trigger level shift */
124 #define  UCR4_CTSTL_MASK 0x3F    /* CTS trigger is 6 bits wide */
125 #define  UCR4_INVR  	 (1<<9)  /* Inverted infrared reception */
126 #define  UCR4_ENIRI 	 (1<<8)  /* Serial infrared interrupt enable */
127 #define  UCR4_WKEN  	 (1<<7)  /* Wake interrupt enable */
128 #define  UCR4_REF16 	 (1<<6)  /* Ref freq 16 MHz */
129 #define  UCR4_IRSC  	 (1<<5)  /* IR special case */
130 #define  UCR4_TCEN  	 (1<<3)  /* Transmit complete interrupt enable */
131 #define  UCR4_BKEN  	 (1<<2)  /* Break condition interrupt enable */
132 #define  UCR4_OREN  	 (1<<1)  /* Receiver overrun interrupt enable */
133 #define  UCR4_DREN  	 (1<<0)  /* Recv data ready interrupt enable */
134 #define  UFCR_RXTL_SHF   0       /* Receiver trigger level shift */
135 #define  UFCR_RFDIV      (7<<7)  /* Reference freq divider mask */
136 #define  UFCR_RFDIV_REG(x)	(((x) < 7 ? 6 - (x) : 6) << 7)
137 #define  UFCR_TXTL_SHF   10      /* Transmitter trigger level shift */
138 #define  USR1_PARITYERR  (1<<15) /* Parity error interrupt flag */
139 #define  USR1_RTSS  	 (1<<14) /* RTS pin status */
140 #define  USR1_TRDY  	 (1<<13) /* Transmitter ready interrupt/dma flag */
141 #define  USR1_RTSD  	 (1<<12) /* RTS delta */
142 #define  USR1_ESCF  	 (1<<11) /* Escape seq interrupt flag */
143 #define  USR1_FRAMERR    (1<<10) /* Frame error interrupt flag */
144 #define  USR1_RRDY       (1<<9)	 /* Receiver ready interrupt/dma flag */
145 #define  USR1_TIMEOUT    (1<<7)	 /* Receive timeout interrupt status */
146 #define  USR1_RXDS  	 (1<<6)	 /* Receiver idle interrupt flag */
147 #define  USR1_AIRINT	 (1<<5)	 /* Async IR wake interrupt flag */
148 #define  USR1_AWAKE 	 (1<<4)	 /* Aysnc wake interrupt flag */
149 #define  USR2_ADET  	 (1<<15) /* Auto baud rate detect complete */
150 #define  USR2_TXFE  	 (1<<14) /* Transmit buffer FIFO empty */
151 #define  USR2_DTRF  	 (1<<13) /* DTR edge interrupt flag */
152 #define  USR2_IDLE  	 (1<<12) /* Idle condition */
153 #define  USR2_IRINT 	 (1<<8)	 /* Serial infrared interrupt flag */
154 #define  USR2_WAKE  	 (1<<7)	 /* Wake */
155 #define  USR2_RTSF  	 (1<<4)	 /* RTS edge interrupt flag */
156 #define  USR2_TXDC  	 (1<<3)	 /* Transmitter complete */
157 #define  USR2_BRCD  	 (1<<2)	 /* Break condition */
158 #define  USR2_ORE        (1<<1)	 /* Overrun error */
159 #define  USR2_RDR        (1<<0)	 /* Recv data ready */
160 #define  UTS_FRCPERR	 (1<<13) /* Force parity error */
161 #define  UTS_LOOP        (1<<12) /* Loop tx and rx */
162 #define  UTS_TXEMPTY	 (1<<6)	 /* TxFIFO empty */
163 #define  UTS_RXEMPTY	 (1<<5)	 /* RxFIFO empty */
164 #define  UTS_TXFULL 	 (1<<4)	 /* TxFIFO full */
165 #define  UTS_RXFULL 	 (1<<3)	 /* RxFIFO full */
166 #define  UTS_SOFTRST	 (1<<0)	 /* Software reset */
167 
168 /* We've been assigned a range on the "Low-density serial ports" major */
169 #define SERIAL_IMX_MAJOR        207
170 #define MINOR_START	        16
171 #define DEV_NAME		"ttymxc"
172 
173 /*
174  * This determines how often we check the modem status signals
175  * for any change.  They generally aren't connected to an IRQ
176  * so we have to poll them.  We also check immediately before
177  * filling the TX fifo incase CTS has been dropped.
178  */
179 #define MCTRL_TIMEOUT	(250*HZ/1000)
180 
181 #define DRIVER_NAME "IMX-uart"
182 
183 #define UART_NR 8
184 
185 /* i.mx21 type uart runs on all i.mx except i.mx1 */
186 enum imx_uart_type {
187 	IMX1_UART,
188 	IMX21_UART,
189 };
190 
191 /* device type dependent stuff */
192 struct imx_uart_data {
193 	unsigned uts_reg;
194 	enum imx_uart_type devtype;
195 };
196 
197 struct imx_port {
198 	struct uart_port	port;
199 	struct timer_list	timer;
200 	unsigned int		old_status;
201 	int			txirq,rxirq,rtsirq;
202 	unsigned int		have_rtscts:1;
203 	unsigned int		use_irda:1;
204 	unsigned int		irda_inv_rx:1;
205 	unsigned int		irda_inv_tx:1;
206 	unsigned short		trcv_delay; /* transceiver delay */
207 	struct clk		*clk_ipg;
208 	struct clk		*clk_per;
209 	struct imx_uart_data	*devdata;
210 };
211 
212 struct imx_port_ucrs {
213 	unsigned int	ucr1;
214 	unsigned int	ucr2;
215 	unsigned int	ucr3;
216 };
217 
218 #ifdef CONFIG_IRDA
219 #define USE_IRDA(sport)	((sport)->use_irda)
220 #else
221 #define USE_IRDA(sport)	(0)
222 #endif
223 
224 static struct imx_uart_data imx_uart_devdata[] = {
225 	[IMX1_UART] = {
226 		.uts_reg = IMX1_UTS,
227 		.devtype = IMX1_UART,
228 	},
229 	[IMX21_UART] = {
230 		.uts_reg = IMX21_UTS,
231 		.devtype = IMX21_UART,
232 	},
233 };
234 
235 static struct platform_device_id imx_uart_devtype[] = {
236 	{
237 		.name = "imx1-uart",
238 		.driver_data = (kernel_ulong_t) &imx_uart_devdata[IMX1_UART],
239 	}, {
240 		.name = "imx21-uart",
241 		.driver_data = (kernel_ulong_t) &imx_uart_devdata[IMX21_UART],
242 	}, {
243 		/* sentinel */
244 	}
245 };
246 MODULE_DEVICE_TABLE(platform, imx_uart_devtype);
247 
248 static struct of_device_id imx_uart_dt_ids[] = {
249 	{ .compatible = "fsl,imx1-uart", .data = &imx_uart_devdata[IMX1_UART], },
250 	{ .compatible = "fsl,imx21-uart", .data = &imx_uart_devdata[IMX21_UART], },
251 	{ /* sentinel */ }
252 };
253 MODULE_DEVICE_TABLE(of, imx_uart_dt_ids);
254 
255 static inline unsigned uts_reg(struct imx_port *sport)
256 {
257 	return sport->devdata->uts_reg;
258 }
259 
260 static inline int is_imx1_uart(struct imx_port *sport)
261 {
262 	return sport->devdata->devtype == IMX1_UART;
263 }
264 
265 static inline int is_imx21_uart(struct imx_port *sport)
266 {
267 	return sport->devdata->devtype == IMX21_UART;
268 }
269 
270 /*
271  * Save and restore functions for UCR1, UCR2 and UCR3 registers
272  */
273 static void imx_port_ucrs_save(struct uart_port *port,
274 			       struct imx_port_ucrs *ucr)
275 {
276 	/* save control registers */
277 	ucr->ucr1 = readl(port->membase + UCR1);
278 	ucr->ucr2 = readl(port->membase + UCR2);
279 	ucr->ucr3 = readl(port->membase + UCR3);
280 }
281 
282 static void imx_port_ucrs_restore(struct uart_port *port,
283 				  struct imx_port_ucrs *ucr)
284 {
285 	/* restore control registers */
286 	writel(ucr->ucr1, port->membase + UCR1);
287 	writel(ucr->ucr2, port->membase + UCR2);
288 	writel(ucr->ucr3, port->membase + UCR3);
289 }
290 
291 /*
292  * Handle any change of modem status signal since we were last called.
293  */
294 static void imx_mctrl_check(struct imx_port *sport)
295 {
296 	unsigned int status, changed;
297 
298 	status = sport->port.ops->get_mctrl(&sport->port);
299 	changed = status ^ sport->old_status;
300 
301 	if (changed == 0)
302 		return;
303 
304 	sport->old_status = status;
305 
306 	if (changed & TIOCM_RI)
307 		sport->port.icount.rng++;
308 	if (changed & TIOCM_DSR)
309 		sport->port.icount.dsr++;
310 	if (changed & TIOCM_CAR)
311 		uart_handle_dcd_change(&sport->port, status & TIOCM_CAR);
312 	if (changed & TIOCM_CTS)
313 		uart_handle_cts_change(&sport->port, status & TIOCM_CTS);
314 
315 	wake_up_interruptible(&sport->port.state->port.delta_msr_wait);
316 }
317 
318 /*
319  * This is our per-port timeout handler, for checking the
320  * modem status signals.
321  */
322 static void imx_timeout(unsigned long data)
323 {
324 	struct imx_port *sport = (struct imx_port *)data;
325 	unsigned long flags;
326 
327 	if (sport->port.state) {
328 		spin_lock_irqsave(&sport->port.lock, flags);
329 		imx_mctrl_check(sport);
330 		spin_unlock_irqrestore(&sport->port.lock, flags);
331 
332 		mod_timer(&sport->timer, jiffies + MCTRL_TIMEOUT);
333 	}
334 }
335 
336 /*
337  * interrupts disabled on entry
338  */
339 static void imx_stop_tx(struct uart_port *port)
340 {
341 	struct imx_port *sport = (struct imx_port *)port;
342 	unsigned long temp;
343 
344 	if (USE_IRDA(sport)) {
345 		/* half duplex - wait for end of transmission */
346 		int n = 256;
347 		while ((--n > 0) &&
348 		      !(readl(sport->port.membase + USR2) & USR2_TXDC)) {
349 			udelay(5);
350 			barrier();
351 		}
352 		/*
353 		 * irda transceiver - wait a bit more to avoid
354 		 * cutoff, hardware dependent
355 		 */
356 		udelay(sport->trcv_delay);
357 
358 		/*
359 		 * half duplex - reactivate receive mode,
360 		 * flush receive pipe echo crap
361 		 */
362 		if (readl(sport->port.membase + USR2) & USR2_TXDC) {
363 			temp = readl(sport->port.membase + UCR1);
364 			temp &= ~(UCR1_TXMPTYEN | UCR1_TRDYEN);
365 			writel(temp, sport->port.membase + UCR1);
366 
367 			temp = readl(sport->port.membase + UCR4);
368 			temp &= ~(UCR4_TCEN);
369 			writel(temp, sport->port.membase + UCR4);
370 
371 			while (readl(sport->port.membase + URXD0) &
372 			       URXD_CHARRDY)
373 				barrier();
374 
375 			temp = readl(sport->port.membase + UCR1);
376 			temp |= UCR1_RRDYEN;
377 			writel(temp, sport->port.membase + UCR1);
378 
379 			temp = readl(sport->port.membase + UCR4);
380 			temp |= UCR4_DREN;
381 			writel(temp, sport->port.membase + UCR4);
382 		}
383 		return;
384 	}
385 
386 	temp = readl(sport->port.membase + UCR1);
387 	writel(temp & ~UCR1_TXMPTYEN, sport->port.membase + UCR1);
388 }
389 
390 /*
391  * interrupts disabled on entry
392  */
393 static void imx_stop_rx(struct uart_port *port)
394 {
395 	struct imx_port *sport = (struct imx_port *)port;
396 	unsigned long temp;
397 
398 	temp = readl(sport->port.membase + UCR2);
399 	writel(temp &~ UCR2_RXEN, sport->port.membase + UCR2);
400 }
401 
402 /*
403  * Set the modem control timer to fire immediately.
404  */
405 static void imx_enable_ms(struct uart_port *port)
406 {
407 	struct imx_port *sport = (struct imx_port *)port;
408 
409 	mod_timer(&sport->timer, jiffies);
410 }
411 
412 static inline void imx_transmit_buffer(struct imx_port *sport)
413 {
414 	struct circ_buf *xmit = &sport->port.state->xmit;
415 
416 	while (!uart_circ_empty(xmit) &&
417 			!(readl(sport->port.membase + uts_reg(sport))
418 				& UTS_TXFULL)) {
419 		/* send xmit->buf[xmit->tail]
420 		 * out the port here */
421 		writel(xmit->buf[xmit->tail], sport->port.membase + URTX0);
422 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
423 		sport->port.icount.tx++;
424 	}
425 
426 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
427 		uart_write_wakeup(&sport->port);
428 
429 	if (uart_circ_empty(xmit))
430 		imx_stop_tx(&sport->port);
431 }
432 
433 /*
434  * interrupts disabled on entry
435  */
436 static void imx_start_tx(struct uart_port *port)
437 {
438 	struct imx_port *sport = (struct imx_port *)port;
439 	unsigned long temp;
440 
441 	if (USE_IRDA(sport)) {
442 		/* half duplex in IrDA mode; have to disable receive mode */
443 		temp = readl(sport->port.membase + UCR4);
444 		temp &= ~(UCR4_DREN);
445 		writel(temp, sport->port.membase + UCR4);
446 
447 		temp = readl(sport->port.membase + UCR1);
448 		temp &= ~(UCR1_RRDYEN);
449 		writel(temp, sport->port.membase + UCR1);
450 	}
451 
452 	temp = readl(sport->port.membase + UCR1);
453 	writel(temp | UCR1_TXMPTYEN, sport->port.membase + UCR1);
454 
455 	if (USE_IRDA(sport)) {
456 		temp = readl(sport->port.membase + UCR1);
457 		temp |= UCR1_TRDYEN;
458 		writel(temp, sport->port.membase + UCR1);
459 
460 		temp = readl(sport->port.membase + UCR4);
461 		temp |= UCR4_TCEN;
462 		writel(temp, sport->port.membase + UCR4);
463 	}
464 
465 	if (readl(sport->port.membase + uts_reg(sport)) & UTS_TXEMPTY)
466 		imx_transmit_buffer(sport);
467 }
468 
469 static irqreturn_t imx_rtsint(int irq, void *dev_id)
470 {
471 	struct imx_port *sport = dev_id;
472 	unsigned int val;
473 	unsigned long flags;
474 
475 	spin_lock_irqsave(&sport->port.lock, flags);
476 
477 	writel(USR1_RTSD, sport->port.membase + USR1);
478 	val = readl(sport->port.membase + USR1) & USR1_RTSS;
479 	uart_handle_cts_change(&sport->port, !!val);
480 	wake_up_interruptible(&sport->port.state->port.delta_msr_wait);
481 
482 	spin_unlock_irqrestore(&sport->port.lock, flags);
483 	return IRQ_HANDLED;
484 }
485 
486 static irqreturn_t imx_txint(int irq, void *dev_id)
487 {
488 	struct imx_port *sport = dev_id;
489 	struct circ_buf *xmit = &sport->port.state->xmit;
490 	unsigned long flags;
491 
492 	spin_lock_irqsave(&sport->port.lock,flags);
493 	if (sport->port.x_char)
494 	{
495 		/* Send next char */
496 		writel(sport->port.x_char, sport->port.membase + URTX0);
497 		goto out;
498 	}
499 
500 	if (uart_circ_empty(xmit) || uart_tx_stopped(&sport->port)) {
501 		imx_stop_tx(&sport->port);
502 		goto out;
503 	}
504 
505 	imx_transmit_buffer(sport);
506 
507 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
508 		uart_write_wakeup(&sport->port);
509 
510 out:
511 	spin_unlock_irqrestore(&sport->port.lock,flags);
512 	return IRQ_HANDLED;
513 }
514 
515 static irqreturn_t imx_rxint(int irq, void *dev_id)
516 {
517 	struct imx_port *sport = dev_id;
518 	unsigned int rx,flg,ignored = 0;
519 	struct tty_struct *tty = sport->port.state->port.tty;
520 	unsigned long flags, temp;
521 
522 	spin_lock_irqsave(&sport->port.lock,flags);
523 
524 	while (readl(sport->port.membase + USR2) & USR2_RDR) {
525 		flg = TTY_NORMAL;
526 		sport->port.icount.rx++;
527 
528 		rx = readl(sport->port.membase + URXD0);
529 
530 		temp = readl(sport->port.membase + USR2);
531 		if (temp & USR2_BRCD) {
532 			writel(USR2_BRCD, sport->port.membase + USR2);
533 			if (uart_handle_break(&sport->port))
534 				continue;
535 		}
536 
537 		if (uart_handle_sysrq_char(&sport->port, (unsigned char)rx))
538 			continue;
539 
540 		if (unlikely(rx & URXD_ERR)) {
541 			if (rx & URXD_BRK)
542 				sport->port.icount.brk++;
543 			else if (rx & URXD_PRERR)
544 				sport->port.icount.parity++;
545 			else if (rx & URXD_FRMERR)
546 				sport->port.icount.frame++;
547 			if (rx & URXD_OVRRUN)
548 				sport->port.icount.overrun++;
549 
550 			if (rx & sport->port.ignore_status_mask) {
551 				if (++ignored > 100)
552 					goto out;
553 				continue;
554 			}
555 
556 			rx &= sport->port.read_status_mask;
557 
558 			if (rx & URXD_BRK)
559 				flg = TTY_BREAK;
560 			else if (rx & URXD_PRERR)
561 				flg = TTY_PARITY;
562 			else if (rx & URXD_FRMERR)
563 				flg = TTY_FRAME;
564 			if (rx & URXD_OVRRUN)
565 				flg = TTY_OVERRUN;
566 
567 #ifdef SUPPORT_SYSRQ
568 			sport->port.sysrq = 0;
569 #endif
570 		}
571 
572 		tty_insert_flip_char(tty, rx, flg);
573 	}
574 
575 out:
576 	spin_unlock_irqrestore(&sport->port.lock,flags);
577 	tty_flip_buffer_push(tty);
578 	return IRQ_HANDLED;
579 }
580 
581 static irqreturn_t imx_int(int irq, void *dev_id)
582 {
583 	struct imx_port *sport = dev_id;
584 	unsigned int sts;
585 
586 	sts = readl(sport->port.membase + USR1);
587 
588 	if (sts & USR1_RRDY)
589 		imx_rxint(irq, dev_id);
590 
591 	if (sts & USR1_TRDY &&
592 			readl(sport->port.membase + UCR1) & UCR1_TXMPTYEN)
593 		imx_txint(irq, dev_id);
594 
595 	if (sts & USR1_RTSD)
596 		imx_rtsint(irq, dev_id);
597 
598 	if (sts & USR1_AWAKE)
599 		writel(USR1_AWAKE, sport->port.membase + USR1);
600 
601 	return IRQ_HANDLED;
602 }
603 
604 /*
605  * Return TIOCSER_TEMT when transmitter is not busy.
606  */
607 static unsigned int imx_tx_empty(struct uart_port *port)
608 {
609 	struct imx_port *sport = (struct imx_port *)port;
610 
611 	return (readl(sport->port.membase + USR2) & USR2_TXDC) ?  TIOCSER_TEMT : 0;
612 }
613 
614 /*
615  * We have a modem side uart, so the meanings of RTS and CTS are inverted.
616  */
617 static unsigned int imx_get_mctrl(struct uart_port *port)
618 {
619 	struct imx_port *sport = (struct imx_port *)port;
620 	unsigned int tmp = TIOCM_DSR | TIOCM_CAR;
621 
622 	if (readl(sport->port.membase + USR1) & USR1_RTSS)
623 		tmp |= TIOCM_CTS;
624 
625 	if (readl(sport->port.membase + UCR2) & UCR2_CTS)
626 		tmp |= TIOCM_RTS;
627 
628 	return tmp;
629 }
630 
631 static void imx_set_mctrl(struct uart_port *port, unsigned int mctrl)
632 {
633 	struct imx_port *sport = (struct imx_port *)port;
634 	unsigned long temp;
635 
636 	temp = readl(sport->port.membase + UCR2) & ~UCR2_CTS;
637 
638 	if (mctrl & TIOCM_RTS)
639 		temp |= UCR2_CTS;
640 
641 	writel(temp, sport->port.membase + UCR2);
642 }
643 
644 /*
645  * Interrupts always disabled.
646  */
647 static void imx_break_ctl(struct uart_port *port, int break_state)
648 {
649 	struct imx_port *sport = (struct imx_port *)port;
650 	unsigned long flags, temp;
651 
652 	spin_lock_irqsave(&sport->port.lock, flags);
653 
654 	temp = readl(sport->port.membase + UCR1) & ~UCR1_SNDBRK;
655 
656 	if ( break_state != 0 )
657 		temp |= UCR1_SNDBRK;
658 
659 	writel(temp, sport->port.membase + UCR1);
660 
661 	spin_unlock_irqrestore(&sport->port.lock, flags);
662 }
663 
664 #define TXTL 2 /* reset default */
665 #define RXTL 1 /* reset default */
666 
667 static int imx_setup_ufcr(struct imx_port *sport, unsigned int mode)
668 {
669 	unsigned int val;
670 	unsigned int ufcr_rfdiv;
671 
672 	/* set receiver / transmitter trigger level.
673 	 * RFDIV is set such way to satisfy requested uartclk value
674 	 */
675 	val = TXTL << 10 | RXTL;
676 	ufcr_rfdiv = (clk_get_rate(sport->clk_per) + sport->port.uartclk / 2)
677 			/ sport->port.uartclk;
678 
679 	if(!ufcr_rfdiv)
680 		ufcr_rfdiv = 1;
681 
682 	val |= UFCR_RFDIV_REG(ufcr_rfdiv);
683 
684 	writel(val, sport->port.membase + UFCR);
685 
686 	return 0;
687 }
688 
689 /* half the RX buffer size */
690 #define CTSTL 16
691 
692 static int imx_startup(struct uart_port *port)
693 {
694 	struct imx_port *sport = (struct imx_port *)port;
695 	int retval;
696 	unsigned long flags, temp;
697 
698 	imx_setup_ufcr(sport, 0);
699 
700 	/* disable the DREN bit (Data Ready interrupt enable) before
701 	 * requesting IRQs
702 	 */
703 	temp = readl(sport->port.membase + UCR4);
704 
705 	if (USE_IRDA(sport))
706 		temp |= UCR4_IRSC;
707 
708 	/* set the trigger level for CTS */
709 	temp &= ~(UCR4_CTSTL_MASK<<  UCR4_CTSTL_SHF);
710 	temp |= CTSTL<<  UCR4_CTSTL_SHF;
711 
712 	writel(temp & ~UCR4_DREN, sport->port.membase + UCR4);
713 
714 	if (USE_IRDA(sport)) {
715 		/* reset fifo's and state machines */
716 		int i = 100;
717 		temp = readl(sport->port.membase + UCR2);
718 		temp &= ~UCR2_SRST;
719 		writel(temp, sport->port.membase + UCR2);
720 		while (!(readl(sport->port.membase + UCR2) & UCR2_SRST) &&
721 		    (--i > 0)) {
722 			udelay(1);
723 		}
724 	}
725 
726 	/*
727 	 * Allocate the IRQ(s) i.MX1 has three interrupts whereas later
728 	 * chips only have one interrupt.
729 	 */
730 	if (sport->txirq > 0) {
731 		retval = request_irq(sport->rxirq, imx_rxint, 0,
732 				DRIVER_NAME, sport);
733 		if (retval)
734 			goto error_out1;
735 
736 		retval = request_irq(sport->txirq, imx_txint, 0,
737 				DRIVER_NAME, sport);
738 		if (retval)
739 			goto error_out2;
740 
741 		/* do not use RTS IRQ on IrDA */
742 		if (!USE_IRDA(sport)) {
743 			retval = request_irq(sport->rtsirq, imx_rtsint, 0,
744 					DRIVER_NAME, sport);
745 			if (retval)
746 				goto error_out3;
747 		}
748 	} else {
749 		retval = request_irq(sport->port.irq, imx_int, 0,
750 				DRIVER_NAME, sport);
751 		if (retval) {
752 			free_irq(sport->port.irq, sport);
753 			goto error_out1;
754 		}
755 	}
756 
757 	/*
758 	 * Finally, clear and enable interrupts
759 	 */
760 	writel(USR1_RTSD, sport->port.membase + USR1);
761 
762 	temp = readl(sport->port.membase + UCR1);
763 	temp |= UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN;
764 
765 	if (USE_IRDA(sport)) {
766 		temp |= UCR1_IREN;
767 		temp &= ~(UCR1_RTSDEN);
768 	}
769 
770 	writel(temp, sport->port.membase + UCR1);
771 
772 	temp = readl(sport->port.membase + UCR2);
773 	temp |= (UCR2_RXEN | UCR2_TXEN);
774 	writel(temp, sport->port.membase + UCR2);
775 
776 	if (USE_IRDA(sport)) {
777 		/* clear RX-FIFO */
778 		int i = 64;
779 		while ((--i > 0) &&
780 			(readl(sport->port.membase + URXD0) & URXD_CHARRDY)) {
781 			barrier();
782 		}
783 	}
784 
785 	if (is_imx21_uart(sport)) {
786 		temp = readl(sport->port.membase + UCR3);
787 		temp |= IMX21_UCR3_RXDMUXSEL;
788 		writel(temp, sport->port.membase + UCR3);
789 	}
790 
791 	if (USE_IRDA(sport)) {
792 		temp = readl(sport->port.membase + UCR4);
793 		if (sport->irda_inv_rx)
794 			temp |= UCR4_INVR;
795 		else
796 			temp &= ~(UCR4_INVR);
797 		writel(temp | UCR4_DREN, sport->port.membase + UCR4);
798 
799 		temp = readl(sport->port.membase + UCR3);
800 		if (sport->irda_inv_tx)
801 			temp |= UCR3_INVT;
802 		else
803 			temp &= ~(UCR3_INVT);
804 		writel(temp, sport->port.membase + UCR3);
805 	}
806 
807 	/*
808 	 * Enable modem status interrupts
809 	 */
810 	spin_lock_irqsave(&sport->port.lock,flags);
811 	imx_enable_ms(&sport->port);
812 	spin_unlock_irqrestore(&sport->port.lock,flags);
813 
814 	if (USE_IRDA(sport)) {
815 		struct imxuart_platform_data *pdata;
816 		pdata = sport->port.dev->platform_data;
817 		sport->irda_inv_rx = pdata->irda_inv_rx;
818 		sport->irda_inv_tx = pdata->irda_inv_tx;
819 		sport->trcv_delay = pdata->transceiver_delay;
820 		if (pdata->irda_enable)
821 			pdata->irda_enable(1);
822 	}
823 
824 	return 0;
825 
826 error_out3:
827 	if (sport->txirq)
828 		free_irq(sport->txirq, sport);
829 error_out2:
830 	if (sport->rxirq)
831 		free_irq(sport->rxirq, sport);
832 error_out1:
833 	return retval;
834 }
835 
836 static void imx_shutdown(struct uart_port *port)
837 {
838 	struct imx_port *sport = (struct imx_port *)port;
839 	unsigned long temp;
840 
841 	temp = readl(sport->port.membase + UCR2);
842 	temp &= ~(UCR2_TXEN);
843 	writel(temp, sport->port.membase + UCR2);
844 
845 	if (USE_IRDA(sport)) {
846 		struct imxuart_platform_data *pdata;
847 		pdata = sport->port.dev->platform_data;
848 		if (pdata->irda_enable)
849 			pdata->irda_enable(0);
850 	}
851 
852 	/*
853 	 * Stop our timer.
854 	 */
855 	del_timer_sync(&sport->timer);
856 
857 	/*
858 	 * Free the interrupts
859 	 */
860 	if (sport->txirq > 0) {
861 		if (!USE_IRDA(sport))
862 			free_irq(sport->rtsirq, sport);
863 		free_irq(sport->txirq, sport);
864 		free_irq(sport->rxirq, sport);
865 	} else
866 		free_irq(sport->port.irq, sport);
867 
868 	/*
869 	 * Disable all interrupts, port and break condition.
870 	 */
871 
872 	temp = readl(sport->port.membase + UCR1);
873 	temp &= ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN);
874 	if (USE_IRDA(sport))
875 		temp &= ~(UCR1_IREN);
876 
877 	writel(temp, sport->port.membase + UCR1);
878 }
879 
880 static void
881 imx_set_termios(struct uart_port *port, struct ktermios *termios,
882 		   struct ktermios *old)
883 {
884 	struct imx_port *sport = (struct imx_port *)port;
885 	unsigned long flags;
886 	unsigned int ucr2, old_ucr1, old_txrxen, baud, quot;
887 	unsigned int old_csize = old ? old->c_cflag & CSIZE : CS8;
888 	unsigned int div, ufcr;
889 	unsigned long num, denom;
890 	uint64_t tdiv64;
891 
892 	/*
893 	 * If we don't support modem control lines, don't allow
894 	 * these to be set.
895 	 */
896 	if (0) {
897 		termios->c_cflag &= ~(HUPCL | CRTSCTS | CMSPAR);
898 		termios->c_cflag |= CLOCAL;
899 	}
900 
901 	/*
902 	 * We only support CS7 and CS8.
903 	 */
904 	while ((termios->c_cflag & CSIZE) != CS7 &&
905 	       (termios->c_cflag & CSIZE) != CS8) {
906 		termios->c_cflag &= ~CSIZE;
907 		termios->c_cflag |= old_csize;
908 		old_csize = CS8;
909 	}
910 
911 	if ((termios->c_cflag & CSIZE) == CS8)
912 		ucr2 = UCR2_WS | UCR2_SRST | UCR2_IRTS;
913 	else
914 		ucr2 = UCR2_SRST | UCR2_IRTS;
915 
916 	if (termios->c_cflag & CRTSCTS) {
917 		if( sport->have_rtscts ) {
918 			ucr2 &= ~UCR2_IRTS;
919 			ucr2 |= UCR2_CTSC;
920 		} else {
921 			termios->c_cflag &= ~CRTSCTS;
922 		}
923 	}
924 
925 	if (termios->c_cflag & CSTOPB)
926 		ucr2 |= UCR2_STPB;
927 	if (termios->c_cflag & PARENB) {
928 		ucr2 |= UCR2_PREN;
929 		if (termios->c_cflag & PARODD)
930 			ucr2 |= UCR2_PROE;
931 	}
932 
933 	del_timer_sync(&sport->timer);
934 
935 	/*
936 	 * Ask the core to calculate the divisor for us.
937 	 */
938 	baud = uart_get_baud_rate(port, termios, old, 50, port->uartclk / 16);
939 	quot = uart_get_divisor(port, baud);
940 
941 	spin_lock_irqsave(&sport->port.lock, flags);
942 
943 	sport->port.read_status_mask = 0;
944 	if (termios->c_iflag & INPCK)
945 		sport->port.read_status_mask |= (URXD_FRMERR | URXD_PRERR);
946 	if (termios->c_iflag & (BRKINT | PARMRK))
947 		sport->port.read_status_mask |= URXD_BRK;
948 
949 	/*
950 	 * Characters to ignore
951 	 */
952 	sport->port.ignore_status_mask = 0;
953 	if (termios->c_iflag & IGNPAR)
954 		sport->port.ignore_status_mask |= URXD_PRERR;
955 	if (termios->c_iflag & IGNBRK) {
956 		sport->port.ignore_status_mask |= URXD_BRK;
957 		/*
958 		 * If we're ignoring parity and break indicators,
959 		 * ignore overruns too (for real raw support).
960 		 */
961 		if (termios->c_iflag & IGNPAR)
962 			sport->port.ignore_status_mask |= URXD_OVRRUN;
963 	}
964 
965 	/*
966 	 * Update the per-port timeout.
967 	 */
968 	uart_update_timeout(port, termios->c_cflag, baud);
969 
970 	/*
971 	 * disable interrupts and drain transmitter
972 	 */
973 	old_ucr1 = readl(sport->port.membase + UCR1);
974 	writel(old_ucr1 & ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN),
975 			sport->port.membase + UCR1);
976 
977 	while ( !(readl(sport->port.membase + USR2) & USR2_TXDC))
978 		barrier();
979 
980 	/* then, disable everything */
981 	old_txrxen = readl(sport->port.membase + UCR2);
982 	writel(old_txrxen & ~( UCR2_TXEN | UCR2_RXEN),
983 			sport->port.membase + UCR2);
984 	old_txrxen &= (UCR2_TXEN | UCR2_RXEN);
985 
986 	if (USE_IRDA(sport)) {
987 		/*
988 		 * use maximum available submodule frequency to
989 		 * avoid missing short pulses due to low sampling rate
990 		 */
991 		div = 1;
992 	} else {
993 		div = sport->port.uartclk / (baud * 16);
994 		if (div > 7)
995 			div = 7;
996 		if (!div)
997 			div = 1;
998 	}
999 
1000 	rational_best_approximation(16 * div * baud, sport->port.uartclk,
1001 		1 << 16, 1 << 16, &num, &denom);
1002 
1003 	tdiv64 = sport->port.uartclk;
1004 	tdiv64 *= num;
1005 	do_div(tdiv64, denom * 16 * div);
1006 	tty_termios_encode_baud_rate(termios,
1007 				(speed_t)tdiv64, (speed_t)tdiv64);
1008 
1009 	num -= 1;
1010 	denom -= 1;
1011 
1012 	ufcr = readl(sport->port.membase + UFCR);
1013 	ufcr = (ufcr & (~UFCR_RFDIV)) | UFCR_RFDIV_REG(div);
1014 	writel(ufcr, sport->port.membase + UFCR);
1015 
1016 	writel(num, sport->port.membase + UBIR);
1017 	writel(denom, sport->port.membase + UBMR);
1018 
1019 	if (is_imx21_uart(sport))
1020 		writel(sport->port.uartclk / div / 1000,
1021 				sport->port.membase + IMX21_ONEMS);
1022 
1023 	writel(old_ucr1, sport->port.membase + UCR1);
1024 
1025 	/* set the parity, stop bits and data size */
1026 	writel(ucr2 | old_txrxen, sport->port.membase + UCR2);
1027 
1028 	if (UART_ENABLE_MS(&sport->port, termios->c_cflag))
1029 		imx_enable_ms(&sport->port);
1030 
1031 	spin_unlock_irqrestore(&sport->port.lock, flags);
1032 }
1033 
1034 static const char *imx_type(struct uart_port *port)
1035 {
1036 	struct imx_port *sport = (struct imx_port *)port;
1037 
1038 	return sport->port.type == PORT_IMX ? "IMX" : NULL;
1039 }
1040 
1041 /*
1042  * Release the memory region(s) being used by 'port'.
1043  */
1044 static void imx_release_port(struct uart_port *port)
1045 {
1046 	struct platform_device *pdev = to_platform_device(port->dev);
1047 	struct resource *mmres;
1048 
1049 	mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1050 	release_mem_region(mmres->start, resource_size(mmres));
1051 }
1052 
1053 /*
1054  * Request the memory region(s) being used by 'port'.
1055  */
1056 static int imx_request_port(struct uart_port *port)
1057 {
1058 	struct platform_device *pdev = to_platform_device(port->dev);
1059 	struct resource *mmres;
1060 	void *ret;
1061 
1062 	mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1063 	if (!mmres)
1064 		return -ENODEV;
1065 
1066 	ret = request_mem_region(mmres->start, resource_size(mmres), "imx-uart");
1067 
1068 	return  ret ? 0 : -EBUSY;
1069 }
1070 
1071 /*
1072  * Configure/autoconfigure the port.
1073  */
1074 static void imx_config_port(struct uart_port *port, int flags)
1075 {
1076 	struct imx_port *sport = (struct imx_port *)port;
1077 
1078 	if (flags & UART_CONFIG_TYPE &&
1079 	    imx_request_port(&sport->port) == 0)
1080 		sport->port.type = PORT_IMX;
1081 }
1082 
1083 /*
1084  * Verify the new serial_struct (for TIOCSSERIAL).
1085  * The only change we allow are to the flags and type, and
1086  * even then only between PORT_IMX and PORT_UNKNOWN
1087  */
1088 static int
1089 imx_verify_port(struct uart_port *port, struct serial_struct *ser)
1090 {
1091 	struct imx_port *sport = (struct imx_port *)port;
1092 	int ret = 0;
1093 
1094 	if (ser->type != PORT_UNKNOWN && ser->type != PORT_IMX)
1095 		ret = -EINVAL;
1096 	if (sport->port.irq != ser->irq)
1097 		ret = -EINVAL;
1098 	if (ser->io_type != UPIO_MEM)
1099 		ret = -EINVAL;
1100 	if (sport->port.uartclk / 16 != ser->baud_base)
1101 		ret = -EINVAL;
1102 	if ((void *)sport->port.mapbase != ser->iomem_base)
1103 		ret = -EINVAL;
1104 	if (sport->port.iobase != ser->port)
1105 		ret = -EINVAL;
1106 	if (ser->hub6 != 0)
1107 		ret = -EINVAL;
1108 	return ret;
1109 }
1110 
1111 #if defined(CONFIG_CONSOLE_POLL)
1112 static int imx_poll_get_char(struct uart_port *port)
1113 {
1114 	struct imx_port_ucrs old_ucr;
1115 	unsigned int status;
1116 	unsigned char c;
1117 
1118 	/* save control registers */
1119 	imx_port_ucrs_save(port, &old_ucr);
1120 
1121 	/* disable interrupts */
1122 	writel(UCR1_UARTEN, port->membase + UCR1);
1123 	writel(old_ucr.ucr2 & ~(UCR2_ATEN | UCR2_RTSEN | UCR2_ESCI),
1124 	       port->membase + UCR2);
1125 	writel(old_ucr.ucr3 & ~(UCR3_DCD | UCR3_RI | UCR3_DTREN),
1126 	       port->membase + UCR3);
1127 
1128 	/* poll */
1129 	do {
1130 		status = readl(port->membase + USR2);
1131 	} while (~status & USR2_RDR);
1132 
1133 	/* read */
1134 	c = readl(port->membase + URXD0);
1135 
1136 	/* restore control registers */
1137 	imx_port_ucrs_restore(port, &old_ucr);
1138 
1139 	return c;
1140 }
1141 
1142 static void imx_poll_put_char(struct uart_port *port, unsigned char c)
1143 {
1144 	struct imx_port_ucrs old_ucr;
1145 	unsigned int status;
1146 
1147 	/* save control registers */
1148 	imx_port_ucrs_save(port, &old_ucr);
1149 
1150 	/* disable interrupts */
1151 	writel(UCR1_UARTEN, port->membase + UCR1);
1152 	writel(old_ucr.ucr2 & ~(UCR2_ATEN | UCR2_RTSEN | UCR2_ESCI),
1153 	       port->membase + UCR2);
1154 	writel(old_ucr.ucr3 & ~(UCR3_DCD | UCR3_RI | UCR3_DTREN),
1155 	       port->membase + UCR3);
1156 
1157 	/* drain */
1158 	do {
1159 		status = readl(port->membase + USR1);
1160 	} while (~status & USR1_TRDY);
1161 
1162 	/* write */
1163 	writel(c, port->membase + URTX0);
1164 
1165 	/* flush */
1166 	do {
1167 		status = readl(port->membase + USR2);
1168 	} while (~status & USR2_TXDC);
1169 
1170 	/* restore control registers */
1171 	imx_port_ucrs_restore(port, &old_ucr);
1172 }
1173 #endif
1174 
1175 static struct uart_ops imx_pops = {
1176 	.tx_empty	= imx_tx_empty,
1177 	.set_mctrl	= imx_set_mctrl,
1178 	.get_mctrl	= imx_get_mctrl,
1179 	.stop_tx	= imx_stop_tx,
1180 	.start_tx	= imx_start_tx,
1181 	.stop_rx	= imx_stop_rx,
1182 	.enable_ms	= imx_enable_ms,
1183 	.break_ctl	= imx_break_ctl,
1184 	.startup	= imx_startup,
1185 	.shutdown	= imx_shutdown,
1186 	.set_termios	= imx_set_termios,
1187 	.type		= imx_type,
1188 	.release_port	= imx_release_port,
1189 	.request_port	= imx_request_port,
1190 	.config_port	= imx_config_port,
1191 	.verify_port	= imx_verify_port,
1192 #if defined(CONFIG_CONSOLE_POLL)
1193 	.poll_get_char  = imx_poll_get_char,
1194 	.poll_put_char  = imx_poll_put_char,
1195 #endif
1196 };
1197 
1198 static struct imx_port *imx_ports[UART_NR];
1199 
1200 #ifdef CONFIG_SERIAL_IMX_CONSOLE
1201 static void imx_console_putchar(struct uart_port *port, int ch)
1202 {
1203 	struct imx_port *sport = (struct imx_port *)port;
1204 
1205 	while (readl(sport->port.membase + uts_reg(sport)) & UTS_TXFULL)
1206 		barrier();
1207 
1208 	writel(ch, sport->port.membase + URTX0);
1209 }
1210 
1211 /*
1212  * Interrupts are disabled on entering
1213  */
1214 static void
1215 imx_console_write(struct console *co, const char *s, unsigned int count)
1216 {
1217 	struct imx_port *sport = imx_ports[co->index];
1218 	struct imx_port_ucrs old_ucr;
1219 	unsigned int ucr1;
1220 
1221 	/*
1222 	 *	First, save UCR1/2/3 and then disable interrupts
1223 	 */
1224 	imx_port_ucrs_save(&sport->port, &old_ucr);
1225 	ucr1 = old_ucr.ucr1;
1226 
1227 	if (is_imx1_uart(sport))
1228 		ucr1 |= IMX1_UCR1_UARTCLKEN;
1229 	ucr1 |= UCR1_UARTEN;
1230 	ucr1 &= ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN);
1231 
1232 	writel(ucr1, sport->port.membase + UCR1);
1233 
1234 	writel(old_ucr.ucr2 | UCR2_TXEN, sport->port.membase + UCR2);
1235 
1236 	uart_console_write(&sport->port, s, count, imx_console_putchar);
1237 
1238 	/*
1239 	 *	Finally, wait for transmitter to become empty
1240 	 *	and restore UCR1/2/3
1241 	 */
1242 	while (!(readl(sport->port.membase + USR2) & USR2_TXDC));
1243 
1244 	imx_port_ucrs_restore(&sport->port, &old_ucr);
1245 }
1246 
1247 /*
1248  * If the port was already initialised (eg, by a boot loader),
1249  * try to determine the current setup.
1250  */
1251 static void __init
1252 imx_console_get_options(struct imx_port *sport, int *baud,
1253 			   int *parity, int *bits)
1254 {
1255 
1256 	if (readl(sport->port.membase + UCR1) & UCR1_UARTEN) {
1257 		/* ok, the port was enabled */
1258 		unsigned int ucr2, ubir,ubmr, uartclk;
1259 		unsigned int baud_raw;
1260 		unsigned int ucfr_rfdiv;
1261 
1262 		ucr2 = readl(sport->port.membase + UCR2);
1263 
1264 		*parity = 'n';
1265 		if (ucr2 & UCR2_PREN) {
1266 			if (ucr2 & UCR2_PROE)
1267 				*parity = 'o';
1268 			else
1269 				*parity = 'e';
1270 		}
1271 
1272 		if (ucr2 & UCR2_WS)
1273 			*bits = 8;
1274 		else
1275 			*bits = 7;
1276 
1277 		ubir = readl(sport->port.membase + UBIR) & 0xffff;
1278 		ubmr = readl(sport->port.membase + UBMR) & 0xffff;
1279 
1280 		ucfr_rfdiv = (readl(sport->port.membase + UFCR) & UFCR_RFDIV) >> 7;
1281 		if (ucfr_rfdiv == 6)
1282 			ucfr_rfdiv = 7;
1283 		else
1284 			ucfr_rfdiv = 6 - ucfr_rfdiv;
1285 
1286 		uartclk = clk_get_rate(sport->clk_per);
1287 		uartclk /= ucfr_rfdiv;
1288 
1289 		{	/*
1290 			 * The next code provides exact computation of
1291 			 *   baud_raw = round(((uartclk/16) * (ubir + 1)) / (ubmr + 1))
1292 			 * without need of float support or long long division,
1293 			 * which would be required to prevent 32bit arithmetic overflow
1294 			 */
1295 			unsigned int mul = ubir + 1;
1296 			unsigned int div = 16 * (ubmr + 1);
1297 			unsigned int rem = uartclk % div;
1298 
1299 			baud_raw = (uartclk / div) * mul;
1300 			baud_raw += (rem * mul + div / 2) / div;
1301 			*baud = (baud_raw + 50) / 100 * 100;
1302 		}
1303 
1304 		if(*baud != baud_raw)
1305 			printk(KERN_INFO "Serial: Console IMX rounded baud rate from %d to %d\n",
1306 				baud_raw, *baud);
1307 	}
1308 }
1309 
1310 static int __init
1311 imx_console_setup(struct console *co, char *options)
1312 {
1313 	struct imx_port *sport;
1314 	int baud = 9600;
1315 	int bits = 8;
1316 	int parity = 'n';
1317 	int flow = 'n';
1318 
1319 	/*
1320 	 * Check whether an invalid uart number has been specified, and
1321 	 * if so, search for the first available port that does have
1322 	 * console support.
1323 	 */
1324 	if (co->index == -1 || co->index >= ARRAY_SIZE(imx_ports))
1325 		co->index = 0;
1326 	sport = imx_ports[co->index];
1327 	if(sport == NULL)
1328 		return -ENODEV;
1329 
1330 	if (options)
1331 		uart_parse_options(options, &baud, &parity, &bits, &flow);
1332 	else
1333 		imx_console_get_options(sport, &baud, &parity, &bits);
1334 
1335 	imx_setup_ufcr(sport, 0);
1336 
1337 	return uart_set_options(&sport->port, co, baud, parity, bits, flow);
1338 }
1339 
1340 static struct uart_driver imx_reg;
1341 static struct console imx_console = {
1342 	.name		= DEV_NAME,
1343 	.write		= imx_console_write,
1344 	.device		= uart_console_device,
1345 	.setup		= imx_console_setup,
1346 	.flags		= CON_PRINTBUFFER,
1347 	.index		= -1,
1348 	.data		= &imx_reg,
1349 };
1350 
1351 #define IMX_CONSOLE	&imx_console
1352 #else
1353 #define IMX_CONSOLE	NULL
1354 #endif
1355 
1356 static struct uart_driver imx_reg = {
1357 	.owner          = THIS_MODULE,
1358 	.driver_name    = DRIVER_NAME,
1359 	.dev_name       = DEV_NAME,
1360 	.major          = SERIAL_IMX_MAJOR,
1361 	.minor          = MINOR_START,
1362 	.nr             = ARRAY_SIZE(imx_ports),
1363 	.cons           = IMX_CONSOLE,
1364 };
1365 
1366 static int serial_imx_suspend(struct platform_device *dev, pm_message_t state)
1367 {
1368 	struct imx_port *sport = platform_get_drvdata(dev);
1369 	unsigned int val;
1370 
1371 	/* enable wakeup from i.MX UART */
1372 	val = readl(sport->port.membase + UCR3);
1373 	val |= UCR3_AWAKEN;
1374 	writel(val, sport->port.membase + UCR3);
1375 
1376 	if (sport)
1377 		uart_suspend_port(&imx_reg, &sport->port);
1378 
1379 	return 0;
1380 }
1381 
1382 static int serial_imx_resume(struct platform_device *dev)
1383 {
1384 	struct imx_port *sport = platform_get_drvdata(dev);
1385 	unsigned int val;
1386 
1387 	/* disable wakeup from i.MX UART */
1388 	val = readl(sport->port.membase + UCR3);
1389 	val &= ~UCR3_AWAKEN;
1390 	writel(val, sport->port.membase + UCR3);
1391 
1392 	if (sport)
1393 		uart_resume_port(&imx_reg, &sport->port);
1394 
1395 	return 0;
1396 }
1397 
1398 #ifdef CONFIG_OF
1399 /*
1400  * This function returns 1 iff pdev isn't a device instatiated by dt, 0 iff it
1401  * could successfully get all information from dt or a negative errno.
1402  */
1403 static int serial_imx_probe_dt(struct imx_port *sport,
1404 		struct platform_device *pdev)
1405 {
1406 	struct device_node *np = pdev->dev.of_node;
1407 	const struct of_device_id *of_id =
1408 			of_match_device(imx_uart_dt_ids, &pdev->dev);
1409 	int ret;
1410 
1411 	if (!np)
1412 		/* no device tree device */
1413 		return 1;
1414 
1415 	ret = of_alias_get_id(np, "serial");
1416 	if (ret < 0) {
1417 		dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
1418 		return ret;
1419 	}
1420 	sport->port.line = ret;
1421 
1422 	if (of_get_property(np, "fsl,uart-has-rtscts", NULL))
1423 		sport->have_rtscts = 1;
1424 
1425 	if (of_get_property(np, "fsl,irda-mode", NULL))
1426 		sport->use_irda = 1;
1427 
1428 	sport->devdata = of_id->data;
1429 
1430 	return 0;
1431 }
1432 #else
1433 static inline int serial_imx_probe_dt(struct imx_port *sport,
1434 		struct platform_device *pdev)
1435 {
1436 	return 1;
1437 }
1438 #endif
1439 
1440 static void serial_imx_probe_pdata(struct imx_port *sport,
1441 		struct platform_device *pdev)
1442 {
1443 	struct imxuart_platform_data *pdata = pdev->dev.platform_data;
1444 
1445 	sport->port.line = pdev->id;
1446 	sport->devdata = (struct imx_uart_data	*) pdev->id_entry->driver_data;
1447 
1448 	if (!pdata)
1449 		return;
1450 
1451 	if (pdata->flags & IMXUART_HAVE_RTSCTS)
1452 		sport->have_rtscts = 1;
1453 
1454 	if (pdata->flags & IMXUART_IRDA)
1455 		sport->use_irda = 1;
1456 }
1457 
1458 static int serial_imx_probe(struct platform_device *pdev)
1459 {
1460 	struct imx_port *sport;
1461 	struct imxuart_platform_data *pdata;
1462 	void __iomem *base;
1463 	int ret = 0;
1464 	struct resource *res;
1465 	struct pinctrl *pinctrl;
1466 
1467 	sport = kzalloc(sizeof(*sport), GFP_KERNEL);
1468 	if (!sport)
1469 		return -ENOMEM;
1470 
1471 	ret = serial_imx_probe_dt(sport, pdev);
1472 	if (ret > 0)
1473 		serial_imx_probe_pdata(sport, pdev);
1474 	else if (ret < 0)
1475 		goto free;
1476 
1477 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1478 	if (!res) {
1479 		ret = -ENODEV;
1480 		goto free;
1481 	}
1482 
1483 	base = ioremap(res->start, PAGE_SIZE);
1484 	if (!base) {
1485 		ret = -ENOMEM;
1486 		goto free;
1487 	}
1488 
1489 	sport->port.dev = &pdev->dev;
1490 	sport->port.mapbase = res->start;
1491 	sport->port.membase = base;
1492 	sport->port.type = PORT_IMX,
1493 	sport->port.iotype = UPIO_MEM;
1494 	sport->port.irq = platform_get_irq(pdev, 0);
1495 	sport->rxirq = platform_get_irq(pdev, 0);
1496 	sport->txirq = platform_get_irq(pdev, 1);
1497 	sport->rtsirq = platform_get_irq(pdev, 2);
1498 	sport->port.fifosize = 32;
1499 	sport->port.ops = &imx_pops;
1500 	sport->port.flags = UPF_BOOT_AUTOCONF;
1501 	init_timer(&sport->timer);
1502 	sport->timer.function = imx_timeout;
1503 	sport->timer.data     = (unsigned long)sport;
1504 
1505 	pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
1506 	if (IS_ERR(pinctrl)) {
1507 		ret = PTR_ERR(pinctrl);
1508 		goto unmap;
1509 	}
1510 
1511 	sport->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
1512 	if (IS_ERR(sport->clk_ipg)) {
1513 		ret = PTR_ERR(sport->clk_ipg);
1514 		goto unmap;
1515 	}
1516 
1517 	sport->clk_per = devm_clk_get(&pdev->dev, "per");
1518 	if (IS_ERR(sport->clk_per)) {
1519 		ret = PTR_ERR(sport->clk_per);
1520 		goto unmap;
1521 	}
1522 
1523 	clk_prepare_enable(sport->clk_per);
1524 	clk_prepare_enable(sport->clk_ipg);
1525 
1526 	sport->port.uartclk = clk_get_rate(sport->clk_per);
1527 
1528 	imx_ports[sport->port.line] = sport;
1529 
1530 	pdata = pdev->dev.platform_data;
1531 	if (pdata && pdata->init) {
1532 		ret = pdata->init(pdev);
1533 		if (ret)
1534 			goto clkput;
1535 	}
1536 
1537 	ret = uart_add_one_port(&imx_reg, &sport->port);
1538 	if (ret)
1539 		goto deinit;
1540 	platform_set_drvdata(pdev, &sport->port);
1541 
1542 	return 0;
1543 deinit:
1544 	if (pdata && pdata->exit)
1545 		pdata->exit(pdev);
1546 clkput:
1547 	clk_disable_unprepare(sport->clk_per);
1548 	clk_disable_unprepare(sport->clk_ipg);
1549 unmap:
1550 	iounmap(sport->port.membase);
1551 free:
1552 	kfree(sport);
1553 
1554 	return ret;
1555 }
1556 
1557 static int serial_imx_remove(struct platform_device *pdev)
1558 {
1559 	struct imxuart_platform_data *pdata;
1560 	struct imx_port *sport = platform_get_drvdata(pdev);
1561 
1562 	pdata = pdev->dev.platform_data;
1563 
1564 	platform_set_drvdata(pdev, NULL);
1565 
1566 	uart_remove_one_port(&imx_reg, &sport->port);
1567 
1568 	clk_disable_unprepare(sport->clk_per);
1569 	clk_disable_unprepare(sport->clk_ipg);
1570 
1571 	if (pdata && pdata->exit)
1572 		pdata->exit(pdev);
1573 
1574 	iounmap(sport->port.membase);
1575 	kfree(sport);
1576 
1577 	return 0;
1578 }
1579 
1580 static struct platform_driver serial_imx_driver = {
1581 	.probe		= serial_imx_probe,
1582 	.remove		= serial_imx_remove,
1583 
1584 	.suspend	= serial_imx_suspend,
1585 	.resume		= serial_imx_resume,
1586 	.id_table	= imx_uart_devtype,
1587 	.driver		= {
1588 		.name	= "imx-uart",
1589 		.owner	= THIS_MODULE,
1590 		.of_match_table = imx_uart_dt_ids,
1591 	},
1592 };
1593 
1594 static int __init imx_serial_init(void)
1595 {
1596 	int ret;
1597 
1598 	printk(KERN_INFO "Serial: IMX driver\n");
1599 
1600 	ret = uart_register_driver(&imx_reg);
1601 	if (ret)
1602 		return ret;
1603 
1604 	ret = platform_driver_register(&serial_imx_driver);
1605 	if (ret != 0)
1606 		uart_unregister_driver(&imx_reg);
1607 
1608 	return ret;
1609 }
1610 
1611 static void __exit imx_serial_exit(void)
1612 {
1613 	platform_driver_unregister(&serial_imx_driver);
1614 	uart_unregister_driver(&imx_reg);
1615 }
1616 
1617 module_init(imx_serial_init);
1618 module_exit(imx_serial_exit);
1619 
1620 MODULE_AUTHOR("Sascha Hauer");
1621 MODULE_DESCRIPTION("IMX generic serial port driver");
1622 MODULE_LICENSE("GPL");
1623 MODULE_ALIAS("platform:imx-uart");
1624