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Linux/drivers/tty/serial/imx.c

  1 /*
  2  * Driver for Motorola/Freescale 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  * This program is free software; you can redistribute it and/or modify
 10  * it under the terms of the GNU General Public License as published by
 11  * the Free Software Foundation; either version 2 of the License, or
 12  * (at your option) any later version.
 13  *
 14  * This program is distributed in the hope that it will be useful,
 15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 17  * GNU General Public License for more details.
 18  */
 19 
 20 #if defined(CONFIG_SERIAL_IMX_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
 21 #define SUPPORT_SYSRQ
 22 #endif
 23 
 24 #include <linux/module.h>
 25 #include <linux/ioport.h>
 26 #include <linux/init.h>
 27 #include <linux/console.h>
 28 #include <linux/sysrq.h>
 29 #include <linux/platform_device.h>
 30 #include <linux/tty.h>
 31 #include <linux/tty_flip.h>
 32 #include <linux/serial_core.h>
 33 #include <linux/serial.h>
 34 #include <linux/clk.h>
 35 #include <linux/delay.h>
 36 #include <linux/rational.h>
 37 #include <linux/slab.h>
 38 #include <linux/of.h>
 39 #include <linux/of_device.h>
 40 #include <linux/io.h>
 41 #include <linux/dma-mapping.h>
 42 
 43 #include <asm/irq.h>
 44 #include <linux/platform_data/serial-imx.h>
 45 #include <linux/platform_data/dma-imx.h>
 46 
 47 /* Register definitions */
 48 #define URXD0 0x0  /* Receiver Register */
 49 #define URTX0 0x40 /* Transmitter Register */
 50 #define UCR1  0x80 /* Control Register 1 */
 51 #define UCR2  0x84 /* Control Register 2 */
 52 #define UCR3  0x88 /* Control Register 3 */
 53 #define UCR4  0x8c /* Control Register 4 */
 54 #define UFCR  0x90 /* FIFO Control Register */
 55 #define USR1  0x94 /* Status Register 1 */
 56 #define USR2  0x98 /* Status Register 2 */
 57 #define UESC  0x9c /* Escape Character Register */
 58 #define UTIM  0xa0 /* Escape Timer Register */
 59 #define UBIR  0xa4 /* BRM Incremental Register */
 60 #define UBMR  0xa8 /* BRM Modulator Register */
 61 #define UBRC  0xac /* Baud Rate Count Register */
 62 #define IMX21_ONEMS 0xb0 /* One Millisecond register */
 63 #define IMX1_UTS 0xd0 /* UART Test Register on i.mx1 */
 64 #define IMX21_UTS 0xb4 /* UART Test Register on all other i.mx*/
 65 
 66 /* UART Control Register Bit Fields.*/
 67 #define URXD_DUMMY_READ (1<<16)
 68 #define URXD_CHARRDY    (1<<15)
 69 #define URXD_ERR        (1<<14)
 70 #define URXD_OVRRUN     (1<<13)
 71 #define URXD_FRMERR     (1<<12)
 72 #define URXD_BRK        (1<<11)
 73 #define URXD_PRERR      (1<<10)
 74 #define URXD_RX_DATA    (0xFF<<0)
 75 #define UCR1_ADEN       (1<<15) /* Auto detect interrupt */
 76 #define UCR1_ADBR       (1<<14) /* Auto detect baud rate */
 77 #define UCR1_TRDYEN     (1<<13) /* Transmitter ready interrupt enable */
 78 #define UCR1_IDEN       (1<<12) /* Idle condition interrupt */
 79 #define UCR1_ICD_REG(x) (((x) & 3) << 10) /* idle condition detect */
 80 #define UCR1_RRDYEN     (1<<9)  /* Recv ready interrupt enable */
 81 #define UCR1_RDMAEN     (1<<8)  /* Recv ready DMA enable */
 82 #define UCR1_IREN       (1<<7)  /* Infrared interface enable */
 83 #define UCR1_TXMPTYEN   (1<<6)  /* Transimitter empty interrupt enable */
 84 #define UCR1_RTSDEN     (1<<5)  /* RTS delta interrupt enable */
 85 #define UCR1_SNDBRK     (1<<4)  /* Send break */
 86 #define UCR1_TDMAEN     (1<<3)  /* Transmitter ready DMA enable */
 87 #define IMX1_UCR1_UARTCLKEN (1<<2) /* UART clock enabled, i.mx1 only */
 88 #define UCR1_ATDMAEN    (1<<2)  /* Aging DMA Timer Enable */
 89 #define UCR1_DOZE       (1<<1)  /* Doze */
 90 #define UCR1_UARTEN     (1<<0)  /* UART enabled */
 91 #define UCR2_ESCI       (1<<15) /* Escape seq interrupt enable */
 92 #define UCR2_IRTS       (1<<14) /* Ignore RTS pin */
 93 #define UCR2_CTSC       (1<<13) /* CTS pin control */
 94 #define UCR2_CTS        (1<<12) /* Clear to send */
 95 #define UCR2_ESCEN      (1<<11) /* Escape enable */
 96 #define UCR2_PREN       (1<<8)  /* Parity enable */
 97 #define UCR2_PROE       (1<<7)  /* Parity odd/even */
 98 #define UCR2_STPB       (1<<6)  /* Stop */
 99 #define UCR2_WS         (1<<5)  /* Word size */
100 #define UCR2_RTSEN      (1<<4)  /* Request to send interrupt enable */
101 #define UCR2_ATEN       (1<<3)  /* Aging Timer Enable */
102 #define UCR2_TXEN       (1<<2)  /* Transmitter enabled */
103 #define UCR2_RXEN       (1<<1)  /* Receiver enabled */
104 #define UCR2_SRST       (1<<0)  /* SW reset */
105 #define UCR3_DTREN      (1<<13) /* DTR interrupt enable */
106 #define UCR3_PARERREN   (1<<12) /* Parity enable */
107 #define UCR3_FRAERREN   (1<<11) /* Frame error interrupt enable */
108 #define UCR3_DSR        (1<<10) /* Data set ready */
109 #define UCR3_DCD        (1<<9)  /* Data carrier detect */
110 #define UCR3_RI         (1<<8)  /* Ring indicator */
111 #define UCR3_ADNIMP     (1<<7)  /* Autobaud Detection Not Improved */
112 #define UCR3_RXDSEN     (1<<6)  /* Receive status interrupt enable */
113 #define UCR3_AIRINTEN   (1<<5)  /* Async IR wake interrupt enable */
114 #define UCR3_AWAKEN     (1<<4)  /* Async wake interrupt enable */
115 #define IMX21_UCR3_RXDMUXSEL    (1<<2)  /* RXD Muxed Input Select */
116 #define UCR3_INVT       (1<<1)  /* Inverted Infrared transmission */
117 #define UCR3_BPEN       (1<<0)  /* Preset registers enable */
118 #define UCR4_CTSTL_SHF  10      /* CTS trigger level shift */
119 #define UCR4_CTSTL_MASK 0x3F    /* CTS trigger is 6 bits wide */
120 #define UCR4_INVR       (1<<9)  /* Inverted infrared reception */
121 #define UCR4_ENIRI      (1<<8)  /* Serial infrared interrupt enable */
122 #define UCR4_WKEN       (1<<7)  /* Wake interrupt enable */
123 #define UCR4_REF16      (1<<6)  /* Ref freq 16 MHz */
124 #define UCR4_IDDMAEN    (1<<6)  /* DMA IDLE Condition Detected */
125 #define UCR4_IRSC       (1<<5)  /* IR special case */
126 #define UCR4_TCEN       (1<<3)  /* Transmit complete interrupt enable */
127 #define UCR4_BKEN       (1<<2)  /* Break condition interrupt enable */
128 #define UCR4_OREN       (1<<1)  /* Receiver overrun interrupt enable */
129 #define UCR4_DREN       (1<<0)  /* Recv data ready interrupt enable */
130 #define UFCR_RXTL_SHF   0       /* Receiver trigger level shift */
131 #define UFCR_DCEDTE     (1<<6)  /* DCE/DTE mode select */
132 #define UFCR_RFDIV      (7<<7)  /* Reference freq divider mask */
133 #define UFCR_RFDIV_REG(x)       (((x) < 7 ? 6 - (x) : 6) << 7)
134 #define UFCR_TXTL_SHF   10      /* Transmitter trigger level shift */
135 #define USR1_PARITYERR  (1<<15) /* Parity error interrupt flag */
136 #define USR1_RTSS       (1<<14) /* RTS pin status */
137 #define USR1_TRDY       (1<<13) /* Transmitter ready interrupt/dma flag */
138 #define USR1_RTSD       (1<<12) /* RTS delta */
139 #define USR1_ESCF       (1<<11) /* Escape seq interrupt flag */
140 #define USR1_FRAMERR    (1<<10) /* Frame error interrupt flag */
141 #define USR1_RRDY       (1<<9)   /* Receiver ready interrupt/dma flag */
142 #define USR1_AGTIM      (1<<8)   /* Ageing timer interrupt flag */
143 #define USR1_TIMEOUT    (1<<7)   /* Receive timeout interrupt status */
144 #define USR1_RXDS        (1<<6)  /* Receiver idle interrupt flag */
145 #define USR1_AIRINT      (1<<5)  /* Async IR wake interrupt flag */
146 #define USR1_AWAKE       (1<<4)  /* Aysnc wake interrupt flag */
147 #define USR2_ADET        (1<<15) /* Auto baud rate detect complete */
148 #define USR2_TXFE        (1<<14) /* Transmit buffer FIFO empty */
149 #define USR2_DTRF        (1<<13) /* DTR edge interrupt flag */
150 #define USR2_IDLE        (1<<12) /* Idle condition */
151 #define USR2_IRINT       (1<<8)  /* Serial infrared interrupt flag */
152 #define USR2_WAKE        (1<<7)  /* Wake */
153 #define USR2_RTSF        (1<<4)  /* RTS edge interrupt flag */
154 #define USR2_TXDC        (1<<3)  /* Transmitter complete */
155 #define USR2_BRCD        (1<<2)  /* Break condition */
156 #define USR2_ORE        (1<<1)   /* Overrun error */
157 #define USR2_RDR        (1<<0)   /* Recv data ready */
158 #define UTS_FRCPERR     (1<<13) /* Force parity error */
159 #define UTS_LOOP        (1<<12)  /* Loop tx and rx */
160 #define UTS_TXEMPTY      (1<<6)  /* TxFIFO empty */
161 #define UTS_RXEMPTY      (1<<5)  /* RxFIFO empty */
162 #define UTS_TXFULL       (1<<4)  /* TxFIFO full */
163 #define UTS_RXFULL       (1<<3)  /* RxFIFO full */
164 #define UTS_SOFTRST      (1<<0)  /* Software reset */
165 
166 /* We've been assigned a range on the "Low-density serial ports" major */
167 #define SERIAL_IMX_MAJOR        207
168 #define MINOR_START             16
169 #define DEV_NAME                "ttymxc"
170 
171 /*
172  * This determines how often we check the modem status signals
173  * for any change.  They generally aren't connected to an IRQ
174  * so we have to poll them.  We also check immediately before
175  * filling the TX fifo incase CTS has been dropped.
176  */
177 #define MCTRL_TIMEOUT   (250*HZ/1000)
178 
179 #define DRIVER_NAME "IMX-uart"
180 
181 #define UART_NR 8
182 
183 /* i.MX21 type uart runs on all i.mx except i.MX1 and i.MX6q */
184 enum imx_uart_type {
185         IMX1_UART,
186         IMX21_UART,
187         IMX6Q_UART,
188 };
189 
190 /* device type dependent stuff */
191 struct imx_uart_data {
192         unsigned uts_reg;
193         enum imx_uart_type devtype;
194 };
195 
196 struct imx_port {
197         struct uart_port        port;
198         struct timer_list       timer;
199         unsigned int            old_status;
200         unsigned int            have_rtscts:1;
201         unsigned int            dte_mode:1;
202         unsigned int            irda_inv_rx:1;
203         unsigned int            irda_inv_tx:1;
204         unsigned short          trcv_delay; /* transceiver delay */
205         struct clk              *clk_ipg;
206         struct clk              *clk_per;
207         const struct imx_uart_data *devdata;
208 
209         /* DMA fields */
210         unsigned int            dma_is_inited:1;
211         unsigned int            dma_is_enabled:1;
212         unsigned int            dma_is_rxing:1;
213         unsigned int            dma_is_txing:1;
214         struct dma_chan         *dma_chan_rx, *dma_chan_tx;
215         struct scatterlist      rx_sgl, tx_sgl[2];
216         void                    *rx_buf;
217         unsigned int            tx_bytes;
218         unsigned int            dma_tx_nents;
219         wait_queue_head_t       dma_wait;
220         unsigned int            saved_reg[10];
221         bool                    context_saved;
222 };
223 
224 struct imx_port_ucrs {
225         unsigned int    ucr1;
226         unsigned int    ucr2;
227         unsigned int    ucr3;
228 };
229 
230 static struct imx_uart_data imx_uart_devdata[] = {
231         [IMX1_UART] = {
232                 .uts_reg = IMX1_UTS,
233                 .devtype = IMX1_UART,
234         },
235         [IMX21_UART] = {
236                 .uts_reg = IMX21_UTS,
237                 .devtype = IMX21_UART,
238         },
239         [IMX6Q_UART] = {
240                 .uts_reg = IMX21_UTS,
241                 .devtype = IMX6Q_UART,
242         },
243 };
244 
245 static const struct platform_device_id imx_uart_devtype[] = {
246         {
247                 .name = "imx1-uart",
248                 .driver_data = (kernel_ulong_t) &imx_uart_devdata[IMX1_UART],
249         }, {
250                 .name = "imx21-uart",
251                 .driver_data = (kernel_ulong_t) &imx_uart_devdata[IMX21_UART],
252         }, {
253                 .name = "imx6q-uart",
254                 .driver_data = (kernel_ulong_t) &imx_uart_devdata[IMX6Q_UART],
255         }, {
256                 /* sentinel */
257         }
258 };
259 MODULE_DEVICE_TABLE(platform, imx_uart_devtype);
260 
261 static const struct of_device_id imx_uart_dt_ids[] = {
262         { .compatible = "fsl,imx6q-uart", .data = &imx_uart_devdata[IMX6Q_UART], },
263         { .compatible = "fsl,imx1-uart", .data = &imx_uart_devdata[IMX1_UART], },
264         { .compatible = "fsl,imx21-uart", .data = &imx_uart_devdata[IMX21_UART], },
265         { /* sentinel */ }
266 };
267 MODULE_DEVICE_TABLE(of, imx_uart_dt_ids);
268 
269 static inline unsigned uts_reg(struct imx_port *sport)
270 {
271         return sport->devdata->uts_reg;
272 }
273 
274 static inline int is_imx1_uart(struct imx_port *sport)
275 {
276         return sport->devdata->devtype == IMX1_UART;
277 }
278 
279 static inline int is_imx21_uart(struct imx_port *sport)
280 {
281         return sport->devdata->devtype == IMX21_UART;
282 }
283 
284 static inline int is_imx6q_uart(struct imx_port *sport)
285 {
286         return sport->devdata->devtype == IMX6Q_UART;
287 }
288 /*
289  * Save and restore functions for UCR1, UCR2 and UCR3 registers
290  */
291 #if defined(CONFIG_SERIAL_IMX_CONSOLE)
292 static void imx_port_ucrs_save(struct uart_port *port,
293                                struct imx_port_ucrs *ucr)
294 {
295         /* save control registers */
296         ucr->ucr1 = readl(port->membase + UCR1);
297         ucr->ucr2 = readl(port->membase + UCR2);
298         ucr->ucr3 = readl(port->membase + UCR3);
299 }
300 
301 static void imx_port_ucrs_restore(struct uart_port *port,
302                                   struct imx_port_ucrs *ucr)
303 {
304         /* restore control registers */
305         writel(ucr->ucr1, port->membase + UCR1);
306         writel(ucr->ucr2, port->membase + UCR2);
307         writel(ucr->ucr3, port->membase + UCR3);
308 }
309 #endif
310 
311 /*
312  * Handle any change of modem status signal since we were last called.
313  */
314 static void imx_mctrl_check(struct imx_port *sport)
315 {
316         unsigned int status, changed;
317 
318         status = sport->port.ops->get_mctrl(&sport->port);
319         changed = status ^ sport->old_status;
320 
321         if (changed == 0)
322                 return;
323 
324         sport->old_status = status;
325 
326         if (changed & TIOCM_RI)
327                 sport->port.icount.rng++;
328         if (changed & TIOCM_DSR)
329                 sport->port.icount.dsr++;
330         if (changed & TIOCM_CAR)
331                 uart_handle_dcd_change(&sport->port, status & TIOCM_CAR);
332         if (changed & TIOCM_CTS)
333                 uart_handle_cts_change(&sport->port, status & TIOCM_CTS);
334 
335         wake_up_interruptible(&sport->port.state->port.delta_msr_wait);
336 }
337 
338 /*
339  * This is our per-port timeout handler, for checking the
340  * modem status signals.
341  */
342 static void imx_timeout(unsigned long data)
343 {
344         struct imx_port *sport = (struct imx_port *)data;
345         unsigned long flags;
346 
347         if (sport->port.state) {
348                 spin_lock_irqsave(&sport->port.lock, flags);
349                 imx_mctrl_check(sport);
350                 spin_unlock_irqrestore(&sport->port.lock, flags);
351 
352                 mod_timer(&sport->timer, jiffies + MCTRL_TIMEOUT);
353         }
354 }
355 
356 /*
357  * interrupts disabled on entry
358  */
359 static void imx_stop_tx(struct uart_port *port)
360 {
361         struct imx_port *sport = (struct imx_port *)port;
362         unsigned long temp;
363 
364         /*
365          * We are maybe in the SMP context, so if the DMA TX thread is running
366          * on other cpu, we have to wait for it to finish.
367          */
368         if (sport->dma_is_enabled && sport->dma_is_txing)
369                 return;
370 
371         temp = readl(port->membase + UCR1);
372         writel(temp & ~UCR1_TXMPTYEN, port->membase + UCR1);
373 
374         /* in rs485 mode disable transmitter if shifter is empty */
375         if (port->rs485.flags & SER_RS485_ENABLED &&
376             readl(port->membase + USR2) & USR2_TXDC) {
377                 temp = readl(port->membase + UCR2);
378                 if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND)
379                         temp &= ~UCR2_CTS;
380                 else
381                         temp |= UCR2_CTS;
382                 writel(temp, port->membase + UCR2);
383 
384                 temp = readl(port->membase + UCR4);
385                 temp &= ~UCR4_TCEN;
386                 writel(temp, port->membase + UCR4);
387         }
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         if (sport->dma_is_enabled && sport->dma_is_rxing) {
399                 if (sport->port.suspended) {
400                         dmaengine_terminate_all(sport->dma_chan_rx);
401                         sport->dma_is_rxing = 0;
402                 } else {
403                         return;
404                 }
405         }
406 
407         temp = readl(sport->port.membase + UCR2);
408         writel(temp & ~UCR2_RXEN, sport->port.membase + UCR2);
409 
410         /* disable the `Receiver Ready Interrrupt` */
411         temp = readl(sport->port.membase + UCR1);
412         writel(temp & ~UCR1_RRDYEN, sport->port.membase + UCR1);
413 }
414 
415 /*
416  * Set the modem control timer to fire immediately.
417  */
418 static void imx_enable_ms(struct uart_port *port)
419 {
420         struct imx_port *sport = (struct imx_port *)port;
421 
422         mod_timer(&sport->timer, jiffies);
423 }
424 
425 static void imx_dma_tx(struct imx_port *sport);
426 static inline void imx_transmit_buffer(struct imx_port *sport)
427 {
428         struct circ_buf *xmit = &sport->port.state->xmit;
429         unsigned long temp;
430 
431         if (sport->port.x_char) {
432                 /* Send next char */
433                 writel(sport->port.x_char, sport->port.membase + URTX0);
434                 sport->port.icount.tx++;
435                 sport->port.x_char = 0;
436                 return;
437         }
438 
439         if (uart_circ_empty(xmit) || uart_tx_stopped(&sport->port)) {
440                 imx_stop_tx(&sport->port);
441                 return;
442         }
443 
444         if (sport->dma_is_enabled) {
445                 /*
446                  * We've just sent a X-char Ensure the TX DMA is enabled
447                  * and the TX IRQ is disabled.
448                  **/
449                 temp = readl(sport->port.membase + UCR1);
450                 temp &= ~UCR1_TXMPTYEN;
451                 if (sport->dma_is_txing) {
452                         temp |= UCR1_TDMAEN;
453                         writel(temp, sport->port.membase + UCR1);
454                 } else {
455                         writel(temp, sport->port.membase + UCR1);
456                         imx_dma_tx(sport);
457                 }
458         }
459 
460         while (!uart_circ_empty(xmit) &&
461                !(readl(sport->port.membase + uts_reg(sport)) & UTS_TXFULL)) {
462                 /* send xmit->buf[xmit->tail]
463                  * out the port here */
464                 writel(xmit->buf[xmit->tail], sport->port.membase + URTX0);
465                 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
466                 sport->port.icount.tx++;
467         }
468 
469         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
470                 uart_write_wakeup(&sport->port);
471 
472         if (uart_circ_empty(xmit))
473                 imx_stop_tx(&sport->port);
474 }
475 
476 static void dma_tx_callback(void *data)
477 {
478         struct imx_port *sport = data;
479         struct scatterlist *sgl = &sport->tx_sgl[0];
480         struct circ_buf *xmit = &sport->port.state->xmit;
481         unsigned long flags;
482         unsigned long temp;
483 
484         spin_lock_irqsave(&sport->port.lock, flags);
485 
486         dma_unmap_sg(sport->port.dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE);
487 
488         temp = readl(sport->port.membase + UCR1);
489         temp &= ~UCR1_TDMAEN;
490         writel(temp, sport->port.membase + UCR1);
491 
492         /* update the stat */
493         xmit->tail = (xmit->tail + sport->tx_bytes) & (UART_XMIT_SIZE - 1);
494         sport->port.icount.tx += sport->tx_bytes;
495 
496         dev_dbg(sport->port.dev, "we finish the TX DMA.\n");
497 
498         sport->dma_is_txing = 0;
499 
500         spin_unlock_irqrestore(&sport->port.lock, flags);
501 
502         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
503                 uart_write_wakeup(&sport->port);
504 
505         if (waitqueue_active(&sport->dma_wait)) {
506                 wake_up(&sport->dma_wait);
507                 dev_dbg(sport->port.dev, "exit in %s.\n", __func__);
508                 return;
509         }
510 
511         spin_lock_irqsave(&sport->port.lock, flags);
512         if (!uart_circ_empty(xmit) && !uart_tx_stopped(&sport->port))
513                 imx_dma_tx(sport);
514         spin_unlock_irqrestore(&sport->port.lock, flags);
515 }
516 
517 static void imx_dma_tx(struct imx_port *sport)
518 {
519         struct circ_buf *xmit = &sport->port.state->xmit;
520         struct scatterlist *sgl = sport->tx_sgl;
521         struct dma_async_tx_descriptor *desc;
522         struct dma_chan *chan = sport->dma_chan_tx;
523         struct device *dev = sport->port.dev;
524         unsigned long temp;
525         int ret;
526 
527         if (sport->dma_is_txing)
528                 return;
529 
530         sport->tx_bytes = uart_circ_chars_pending(xmit);
531 
532         if (xmit->tail < xmit->head) {
533                 sport->dma_tx_nents = 1;
534                 sg_init_one(sgl, xmit->buf + xmit->tail, sport->tx_bytes);
535         } else {
536                 sport->dma_tx_nents = 2;
537                 sg_init_table(sgl, 2);
538                 sg_set_buf(sgl, xmit->buf + xmit->tail,
539                                 UART_XMIT_SIZE - xmit->tail);
540                 sg_set_buf(sgl + 1, xmit->buf, xmit->head);
541         }
542 
543         ret = dma_map_sg(dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE);
544         if (ret == 0) {
545                 dev_err(dev, "DMA mapping error for TX.\n");
546                 return;
547         }
548         desc = dmaengine_prep_slave_sg(chan, sgl, sport->dma_tx_nents,
549                                         DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT);
550         if (!desc) {
551                 dma_unmap_sg(dev, sgl, sport->dma_tx_nents,
552                              DMA_TO_DEVICE);
553                 dev_err(dev, "We cannot prepare for the TX slave dma!\n");
554                 return;
555         }
556         desc->callback = dma_tx_callback;
557         desc->callback_param = sport;
558 
559         dev_dbg(dev, "TX: prepare to send %lu bytes by DMA.\n",
560                         uart_circ_chars_pending(xmit));
561 
562         temp = readl(sport->port.membase + UCR1);
563         temp |= UCR1_TDMAEN;
564         writel(temp, sport->port.membase + UCR1);
565 
566         /* fire it */
567         sport->dma_is_txing = 1;
568         dmaengine_submit(desc);
569         dma_async_issue_pending(chan);
570         return;
571 }
572 
573 /*
574  * interrupts disabled on entry
575  */
576 static void imx_start_tx(struct uart_port *port)
577 {
578         struct imx_port *sport = (struct imx_port *)port;
579         unsigned long temp;
580 
581         if (port->rs485.flags & SER_RS485_ENABLED) {
582                 /* enable transmitter and shifter empty irq */
583                 temp = readl(port->membase + UCR2);
584                 if (port->rs485.flags & SER_RS485_RTS_ON_SEND)
585                         temp &= ~UCR2_CTS;
586                 else
587                         temp |= UCR2_CTS;
588                 writel(temp, port->membase + UCR2);
589 
590                 temp = readl(port->membase + UCR4);
591                 temp |= UCR4_TCEN;
592                 writel(temp, port->membase + UCR4);
593         }
594 
595         if (!sport->dma_is_enabled) {
596                 temp = readl(sport->port.membase + UCR1);
597                 writel(temp | UCR1_TXMPTYEN, sport->port.membase + UCR1);
598         }
599 
600         if (sport->dma_is_enabled) {
601                 if (sport->port.x_char) {
602                         /* We have X-char to send, so enable TX IRQ and
603                          * disable TX DMA to let TX interrupt to send X-char */
604                         temp = readl(sport->port.membase + UCR1);
605                         temp &= ~UCR1_TDMAEN;
606                         temp |= UCR1_TXMPTYEN;
607                         writel(temp, sport->port.membase + UCR1);
608                         return;
609                 }
610 
611                 if (!uart_circ_empty(&port->state->xmit) &&
612                     !uart_tx_stopped(port))
613                         imx_dma_tx(sport);
614                 return;
615         }
616 }
617 
618 static irqreturn_t imx_rtsint(int irq, void *dev_id)
619 {
620         struct imx_port *sport = dev_id;
621         unsigned int val;
622         unsigned long flags;
623 
624         spin_lock_irqsave(&sport->port.lock, flags);
625 
626         writel(USR1_RTSD, sport->port.membase + USR1);
627         val = readl(sport->port.membase + USR1) & USR1_RTSS;
628         uart_handle_cts_change(&sport->port, !!val);
629         wake_up_interruptible(&sport->port.state->port.delta_msr_wait);
630 
631         spin_unlock_irqrestore(&sport->port.lock, flags);
632         return IRQ_HANDLED;
633 }
634 
635 static irqreturn_t imx_txint(int irq, void *dev_id)
636 {
637         struct imx_port *sport = dev_id;
638         unsigned long flags;
639 
640         spin_lock_irqsave(&sport->port.lock, flags);
641         imx_transmit_buffer(sport);
642         spin_unlock_irqrestore(&sport->port.lock, flags);
643         return IRQ_HANDLED;
644 }
645 
646 static irqreturn_t imx_rxint(int irq, void *dev_id)
647 {
648         struct imx_port *sport = dev_id;
649         unsigned int rx, flg, ignored = 0;
650         struct tty_port *port = &sport->port.state->port;
651         unsigned long flags, temp;
652 
653         spin_lock_irqsave(&sport->port.lock, flags);
654 
655         while (readl(sport->port.membase + USR2) & USR2_RDR) {
656                 flg = TTY_NORMAL;
657                 sport->port.icount.rx++;
658 
659                 rx = readl(sport->port.membase + URXD0);
660 
661                 temp = readl(sport->port.membase + USR2);
662                 if (temp & USR2_BRCD) {
663                         writel(USR2_BRCD, sport->port.membase + USR2);
664                         if (uart_handle_break(&sport->port))
665                                 continue;
666                 }
667 
668                 if (uart_handle_sysrq_char(&sport->port, (unsigned char)rx))
669                         continue;
670 
671                 if (unlikely(rx & URXD_ERR)) {
672                         if (rx & URXD_BRK)
673                                 sport->port.icount.brk++;
674                         else if (rx & URXD_PRERR)
675                                 sport->port.icount.parity++;
676                         else if (rx & URXD_FRMERR)
677                                 sport->port.icount.frame++;
678                         if (rx & URXD_OVRRUN)
679                                 sport->port.icount.overrun++;
680 
681                         if (rx & sport->port.ignore_status_mask) {
682                                 if (++ignored > 100)
683                                         goto out;
684                                 continue;
685                         }
686 
687                         rx &= (sport->port.read_status_mask | 0xFF);
688 
689                         if (rx & URXD_BRK)
690                                 flg = TTY_BREAK;
691                         else if (rx & URXD_PRERR)
692                                 flg = TTY_PARITY;
693                         else if (rx & URXD_FRMERR)
694                                 flg = TTY_FRAME;
695                         if (rx & URXD_OVRRUN)
696                                 flg = TTY_OVERRUN;
697 
698 #ifdef SUPPORT_SYSRQ
699                         sport->port.sysrq = 0;
700 #endif
701                 }
702 
703                 if (sport->port.ignore_status_mask & URXD_DUMMY_READ)
704                         goto out;
705 
706                 if (tty_insert_flip_char(port, rx, flg) == 0)
707                         sport->port.icount.buf_overrun++;
708         }
709 
710 out:
711         spin_unlock_irqrestore(&sport->port.lock, flags);
712         tty_flip_buffer_push(port);
713         return IRQ_HANDLED;
714 }
715 
716 static int start_rx_dma(struct imx_port *sport);
717 /*
718  * If the RXFIFO is filled with some data, and then we
719  * arise a DMA operation to receive them.
720  */
721 static void imx_dma_rxint(struct imx_port *sport)
722 {
723         unsigned long temp;
724         unsigned long flags;
725 
726         spin_lock_irqsave(&sport->port.lock, flags);
727 
728         temp = readl(sport->port.membase + USR2);
729         if ((temp & USR2_RDR) && !sport->dma_is_rxing) {
730                 sport->dma_is_rxing = 1;
731 
732                 /* disable the receiver ready and aging timer interrupts */
733                 temp = readl(sport->port.membase + UCR1);
734                 temp &= ~(UCR1_RRDYEN);
735                 writel(temp, sport->port.membase + UCR1);
736 
737                 temp = readl(sport->port.membase + UCR2);
738                 temp &= ~(UCR2_ATEN);
739                 writel(temp, sport->port.membase + UCR2);
740 
741                 /* tell the DMA to receive the data. */
742                 start_rx_dma(sport);
743         }
744 
745         spin_unlock_irqrestore(&sport->port.lock, flags);
746 }
747 
748 static irqreturn_t imx_int(int irq, void *dev_id)
749 {
750         struct imx_port *sport = dev_id;
751         unsigned int sts;
752         unsigned int sts2;
753 
754         sts = readl(sport->port.membase + USR1);
755         sts2 = readl(sport->port.membase + USR2);
756 
757         if (sts & (USR1_RRDY | USR1_AGTIM)) {
758                 if (sport->dma_is_enabled)
759                         imx_dma_rxint(sport);
760                 else
761                         imx_rxint(irq, dev_id);
762         }
763 
764         if ((sts & USR1_TRDY &&
765              readl(sport->port.membase + UCR1) & UCR1_TXMPTYEN) ||
766             (sts2 & USR2_TXDC &&
767              readl(sport->port.membase + UCR4) & UCR4_TCEN))
768                 imx_txint(irq, dev_id);
769 
770         if (sts & USR1_RTSD)
771                 imx_rtsint(irq, dev_id);
772 
773         if (sts & USR1_AWAKE)
774                 writel(USR1_AWAKE, sport->port.membase + USR1);
775 
776         if (sts2 & USR2_ORE) {
777                 sport->port.icount.overrun++;
778                 writel(USR2_ORE, sport->port.membase + USR2);
779         }
780 
781         return IRQ_HANDLED;
782 }
783 
784 /*
785  * Return TIOCSER_TEMT when transmitter is not busy.
786  */
787 static unsigned int imx_tx_empty(struct uart_port *port)
788 {
789         struct imx_port *sport = (struct imx_port *)port;
790         unsigned int ret;
791 
792         ret = (readl(sport->port.membase + USR2) & USR2_TXDC) ?  TIOCSER_TEMT : 0;
793 
794         /* If the TX DMA is working, return 0. */
795         if (sport->dma_is_enabled && sport->dma_is_txing)
796                 ret = 0;
797 
798         return ret;
799 }
800 
801 /*
802  * We have a modem side uart, so the meanings of RTS and CTS are inverted.
803  */
804 static unsigned int imx_get_mctrl(struct uart_port *port)
805 {
806         struct imx_port *sport = (struct imx_port *)port;
807         unsigned int tmp = TIOCM_DSR | TIOCM_CAR;
808 
809         if (readl(sport->port.membase + USR1) & USR1_RTSS)
810                 tmp |= TIOCM_CTS;
811 
812         if (readl(sport->port.membase + UCR2) & UCR2_CTS)
813                 tmp |= TIOCM_RTS;
814 
815         if (readl(sport->port.membase + uts_reg(sport)) & UTS_LOOP)
816                 tmp |= TIOCM_LOOP;
817 
818         return tmp;
819 }
820 
821 static void imx_set_mctrl(struct uart_port *port, unsigned int mctrl)
822 {
823         struct imx_port *sport = (struct imx_port *)port;
824         unsigned long temp;
825 
826         if (!(port->rs485.flags & SER_RS485_ENABLED)) {
827                 temp = readl(sport->port.membase + UCR2);
828                 temp &= ~(UCR2_CTS | UCR2_CTSC);
829                 if (mctrl & TIOCM_RTS)
830                         temp |= UCR2_CTS | UCR2_CTSC;
831                 writel(temp, sport->port.membase + UCR2);
832         }
833 
834         temp = readl(sport->port.membase + uts_reg(sport)) & ~UTS_LOOP;
835         if (mctrl & TIOCM_LOOP)
836                 temp |= UTS_LOOP;
837         writel(temp, sport->port.membase + uts_reg(sport));
838 }
839 
840 /*
841  * Interrupts always disabled.
842  */
843 static void imx_break_ctl(struct uart_port *port, int break_state)
844 {
845         struct imx_port *sport = (struct imx_port *)port;
846         unsigned long flags, temp;
847 
848         spin_lock_irqsave(&sport->port.lock, flags);
849 
850         temp = readl(sport->port.membase + UCR1) & ~UCR1_SNDBRK;
851 
852         if (break_state != 0)
853                 temp |= UCR1_SNDBRK;
854 
855         writel(temp, sport->port.membase + UCR1);
856 
857         spin_unlock_irqrestore(&sport->port.lock, flags);
858 }
859 
860 #define RX_BUF_SIZE     (PAGE_SIZE)
861 static void imx_rx_dma_done(struct imx_port *sport)
862 {
863         unsigned long temp;
864         unsigned long flags;
865 
866         spin_lock_irqsave(&sport->port.lock, flags);
867 
868         /* re-enable interrupts to get notified when new symbols are incoming */
869         temp = readl(sport->port.membase + UCR1);
870         temp |= UCR1_RRDYEN;
871         writel(temp, sport->port.membase + UCR1);
872 
873         temp = readl(sport->port.membase + UCR2);
874         temp |= UCR2_ATEN;
875         writel(temp, sport->port.membase + UCR2);
876 
877         sport->dma_is_rxing = 0;
878 
879         /* Is the shutdown waiting for us? */
880         if (waitqueue_active(&sport->dma_wait))
881                 wake_up(&sport->dma_wait);
882 
883         spin_unlock_irqrestore(&sport->port.lock, flags);
884 }
885 
886 /*
887  * There are two kinds of RX DMA interrupts(such as in the MX6Q):
888  *   [1] the RX DMA buffer is full.
889  *   [2] the aging timer expires
890  *
891  * Condition [2] is triggered when a character has been sitting in the FIFO
892  * for at least 8 byte durations.
893  */
894 static void dma_rx_callback(void *data)
895 {
896         struct imx_port *sport = data;
897         struct dma_chan *chan = sport->dma_chan_rx;
898         struct scatterlist *sgl = &sport->rx_sgl;
899         struct tty_port *port = &sport->port.state->port;
900         struct dma_tx_state state;
901         enum dma_status status;
902         unsigned int count;
903 
904         /* unmap it first */
905         dma_unmap_sg(sport->port.dev, sgl, 1, DMA_FROM_DEVICE);
906 
907         status = dmaengine_tx_status(chan, (dma_cookie_t)0, &state);
908         count = RX_BUF_SIZE - state.residue;
909 
910         dev_dbg(sport->port.dev, "We get %d bytes.\n", count);
911 
912         if (count) {
913                 if (!(sport->port.ignore_status_mask & URXD_DUMMY_READ)) {
914                         int bytes = tty_insert_flip_string(port, sport->rx_buf,
915                                         count);
916 
917                         if (bytes != count)
918                                 sport->port.icount.buf_overrun++;
919                 }
920                 tty_flip_buffer_push(port);
921                 sport->port.icount.rx += count;
922         }
923 
924         /*
925          * Restart RX DMA directly if more data is available in order to skip
926          * the roundtrip through the IRQ handler. If there is some data already
927          * in the FIFO, DMA needs to be restarted soon anyways.
928          *
929          * Otherwise stop the DMA and reactivate FIFO IRQs to restart DMA once
930          * data starts to arrive again.
931          */
932         if (readl(sport->port.membase + USR2) & USR2_RDR)
933                 start_rx_dma(sport);
934         else
935                 imx_rx_dma_done(sport);
936 }
937 
938 static int start_rx_dma(struct imx_port *sport)
939 {
940         struct scatterlist *sgl = &sport->rx_sgl;
941         struct dma_chan *chan = sport->dma_chan_rx;
942         struct device *dev = sport->port.dev;
943         struct dma_async_tx_descriptor *desc;
944         int ret;
945 
946         sg_init_one(sgl, sport->rx_buf, RX_BUF_SIZE);
947         ret = dma_map_sg(dev, sgl, 1, DMA_FROM_DEVICE);
948         if (ret == 0) {
949                 dev_err(dev, "DMA mapping error for RX.\n");
950                 return -EINVAL;
951         }
952         desc = dmaengine_prep_slave_sg(chan, sgl, 1, DMA_DEV_TO_MEM,
953                                         DMA_PREP_INTERRUPT);
954         if (!desc) {
955                 dma_unmap_sg(dev, sgl, 1, DMA_FROM_DEVICE);
956                 dev_err(dev, "We cannot prepare for the RX slave dma!\n");
957                 return -EINVAL;
958         }
959         desc->callback = dma_rx_callback;
960         desc->callback_param = sport;
961 
962         dev_dbg(dev, "RX: prepare for the DMA.\n");
963         dmaengine_submit(desc);
964         dma_async_issue_pending(chan);
965         return 0;
966 }
967 
968 #define TXTL_DEFAULT 2 /* reset default */
969 #define RXTL_DEFAULT 1 /* reset default */
970 #define TXTL_DMA 8 /* DMA burst setting */
971 #define RXTL_DMA 9 /* DMA burst setting */
972 
973 static void imx_setup_ufcr(struct imx_port *sport,
974                           unsigned char txwl, unsigned char rxwl)
975 {
976         unsigned int val;
977 
978         /* set receiver / transmitter trigger level */
979         val = readl(sport->port.membase + UFCR) & (UFCR_RFDIV | UFCR_DCEDTE);
980         val |= txwl << UFCR_TXTL_SHF | rxwl;
981         writel(val, sport->port.membase + UFCR);
982 }
983 
984 static void imx_uart_dma_exit(struct imx_port *sport)
985 {
986         if (sport->dma_chan_rx) {
987                 dma_release_channel(sport->dma_chan_rx);
988                 sport->dma_chan_rx = NULL;
989 
990                 kfree(sport->rx_buf);
991                 sport->rx_buf = NULL;
992         }
993 
994         if (sport->dma_chan_tx) {
995                 dma_release_channel(sport->dma_chan_tx);
996                 sport->dma_chan_tx = NULL;
997         }
998 
999         sport->dma_is_inited = 0;
1000 }
1001 
1002 static int imx_uart_dma_init(struct imx_port *sport)
1003 {
1004         struct dma_slave_config slave_config = {};
1005         struct device *dev = sport->port.dev;
1006         int ret;
1007 
1008         /* Prepare for RX : */
1009         sport->dma_chan_rx = dma_request_slave_channel(dev, "rx");
1010         if (!sport->dma_chan_rx) {
1011                 dev_dbg(dev, "cannot get the DMA channel.\n");
1012                 ret = -EINVAL;
1013                 goto err;
1014         }
1015 
1016         slave_config.direction = DMA_DEV_TO_MEM;
1017         slave_config.src_addr = sport->port.mapbase + URXD0;
1018         slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1019         /* one byte less than the watermark level to enable the aging timer */
1020         slave_config.src_maxburst = RXTL_DMA - 1;
1021         ret = dmaengine_slave_config(sport->dma_chan_rx, &slave_config);
1022         if (ret) {
1023                 dev_err(dev, "error in RX dma configuration.\n");
1024                 goto err;
1025         }
1026 
1027         sport->rx_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
1028         if (!sport->rx_buf) {
1029                 ret = -ENOMEM;
1030                 goto err;
1031         }
1032 
1033         /* Prepare for TX : */
1034         sport->dma_chan_tx = dma_request_slave_channel(dev, "tx");
1035         if (!sport->dma_chan_tx) {
1036                 dev_err(dev, "cannot get the TX DMA channel!\n");
1037                 ret = -EINVAL;
1038                 goto err;
1039         }
1040 
1041         slave_config.direction = DMA_MEM_TO_DEV;
1042         slave_config.dst_addr = sport->port.mapbase + URTX0;
1043         slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1044         slave_config.dst_maxburst = TXTL_DMA;
1045         ret = dmaengine_slave_config(sport->dma_chan_tx, &slave_config);
1046         if (ret) {
1047                 dev_err(dev, "error in TX dma configuration.");
1048                 goto err;
1049         }
1050 
1051         sport->dma_is_inited = 1;
1052 
1053         return 0;
1054 err:
1055         imx_uart_dma_exit(sport);
1056         return ret;
1057 }
1058 
1059 static void imx_enable_dma(struct imx_port *sport)
1060 {
1061         unsigned long temp;
1062 
1063         init_waitqueue_head(&sport->dma_wait);
1064 
1065         /* set UCR1 */
1066         temp = readl(sport->port.membase + UCR1);
1067         temp |= UCR1_RDMAEN | UCR1_TDMAEN | UCR1_ATDMAEN;
1068         writel(temp, sport->port.membase + UCR1);
1069 
1070         temp = readl(sport->port.membase + UCR2);
1071         temp |= UCR2_ATEN;
1072         writel(temp, sport->port.membase + UCR2);
1073 
1074         imx_setup_ufcr(sport, TXTL_DMA, RXTL_DMA);
1075 
1076         sport->dma_is_enabled = 1;
1077 }
1078 
1079 static void imx_disable_dma(struct imx_port *sport)
1080 {
1081         unsigned long temp;
1082 
1083         /* clear UCR1 */
1084         temp = readl(sport->port.membase + UCR1);
1085         temp &= ~(UCR1_RDMAEN | UCR1_TDMAEN | UCR1_ATDMAEN);
1086         writel(temp, sport->port.membase + UCR1);
1087 
1088         /* clear UCR2 */
1089         temp = readl(sport->port.membase + UCR2);
1090         temp &= ~(UCR2_CTSC | UCR2_CTS | UCR2_ATEN);
1091         writel(temp, sport->port.membase + UCR2);
1092 
1093         imx_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT);
1094 
1095         sport->dma_is_enabled = 0;
1096 }
1097 
1098 /* half the RX buffer size */
1099 #define CTSTL 16
1100 
1101 static int imx_startup(struct uart_port *port)
1102 {
1103         struct imx_port *sport = (struct imx_port *)port;
1104         int retval, i;
1105         unsigned long flags, temp;
1106 
1107         retval = clk_prepare_enable(sport->clk_per);
1108         if (retval)
1109                 return retval;
1110         retval = clk_prepare_enable(sport->clk_ipg);
1111         if (retval) {
1112                 clk_disable_unprepare(sport->clk_per);
1113                 return retval;
1114         }
1115 
1116         imx_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT);
1117 
1118         /* disable the DREN bit (Data Ready interrupt enable) before
1119          * requesting IRQs
1120          */
1121         temp = readl(sport->port.membase + UCR4);
1122 
1123         /* set the trigger level for CTS */
1124         temp &= ~(UCR4_CTSTL_MASK << UCR4_CTSTL_SHF);
1125         temp |= CTSTL << UCR4_CTSTL_SHF;
1126 
1127         writel(temp & ~UCR4_DREN, sport->port.membase + UCR4);
1128 
1129         /* Can we enable the DMA support? */
1130         if (is_imx6q_uart(sport) && !uart_console(port) &&
1131             !sport->dma_is_inited)
1132                 imx_uart_dma_init(sport);
1133 
1134         spin_lock_irqsave(&sport->port.lock, flags);
1135         /* Reset fifo's and state machines */
1136         i = 100;
1137 
1138         temp = readl(sport->port.membase + UCR2);
1139         temp &= ~UCR2_SRST;
1140         writel(temp, sport->port.membase + UCR2);
1141 
1142         while (!(readl(sport->port.membase + UCR2) & UCR2_SRST) && (--i > 0))
1143                 udelay(1);
1144 
1145         /*
1146          * Finally, clear and enable interrupts
1147          */
1148         writel(USR1_RTSD, sport->port.membase + USR1);
1149         writel(USR2_ORE, sport->port.membase + USR2);
1150 
1151         if (sport->dma_is_inited && !sport->dma_is_enabled)
1152                 imx_enable_dma(sport);
1153 
1154         temp = readl(sport->port.membase + UCR1);
1155         temp |= UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN;
1156 
1157         writel(temp, sport->port.membase + UCR1);
1158 
1159         temp = readl(sport->port.membase + UCR4);
1160         temp |= UCR4_OREN;
1161         writel(temp, sport->port.membase + UCR4);
1162 
1163         temp = readl(sport->port.membase + UCR2);
1164         temp |= (UCR2_RXEN | UCR2_TXEN);
1165         if (!sport->have_rtscts)
1166                 temp |= UCR2_IRTS;
1167         writel(temp, sport->port.membase + UCR2);
1168 
1169         if (!is_imx1_uart(sport)) {
1170                 temp = readl(sport->port.membase + UCR3);
1171                 temp |= IMX21_UCR3_RXDMUXSEL | UCR3_ADNIMP;
1172                 writel(temp, sport->port.membase + UCR3);
1173         }
1174 
1175         /*
1176          * Enable modem status interrupts
1177          */
1178         imx_enable_ms(&sport->port);
1179         spin_unlock_irqrestore(&sport->port.lock, flags);
1180 
1181         return 0;
1182 }
1183 
1184 static void imx_shutdown(struct uart_port *port)
1185 {
1186         struct imx_port *sport = (struct imx_port *)port;
1187         unsigned long temp;
1188         unsigned long flags;
1189 
1190         if (sport->dma_is_enabled) {
1191                 int ret;
1192 
1193                 /* We have to wait for the DMA to finish. */
1194                 ret = wait_event_interruptible(sport->dma_wait,
1195                         !sport->dma_is_rxing && !sport->dma_is_txing);
1196                 if (ret != 0) {
1197                         sport->dma_is_rxing = 0;
1198                         sport->dma_is_txing = 0;
1199                         dmaengine_terminate_all(sport->dma_chan_tx);
1200                         dmaengine_terminate_all(sport->dma_chan_rx);
1201                 }
1202                 spin_lock_irqsave(&sport->port.lock, flags);
1203                 imx_stop_tx(port);
1204                 imx_stop_rx(port);
1205                 imx_disable_dma(sport);
1206                 spin_unlock_irqrestore(&sport->port.lock, flags);
1207                 imx_uart_dma_exit(sport);
1208         }
1209 
1210         spin_lock_irqsave(&sport->port.lock, flags);
1211         temp = readl(sport->port.membase + UCR2);
1212         temp &= ~(UCR2_TXEN);
1213         writel(temp, sport->port.membase + UCR2);
1214         spin_unlock_irqrestore(&sport->port.lock, flags);
1215 
1216         /*
1217          * Stop our timer.
1218          */
1219         del_timer_sync(&sport->timer);
1220 
1221         /*
1222          * Disable all interrupts, port and break condition.
1223          */
1224 
1225         spin_lock_irqsave(&sport->port.lock, flags);
1226         temp = readl(sport->port.membase + UCR1);
1227         temp &= ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN);
1228 
1229         writel(temp, sport->port.membase + UCR1);
1230         spin_unlock_irqrestore(&sport->port.lock, flags);
1231 
1232         clk_disable_unprepare(sport->clk_per);
1233         clk_disable_unprepare(sport->clk_ipg);
1234 }
1235 
1236 static void imx_flush_buffer(struct uart_port *port)
1237 {
1238         struct imx_port *sport = (struct imx_port *)port;
1239         struct scatterlist *sgl = &sport->tx_sgl[0];
1240         unsigned long temp;
1241         int i = 100, ubir, ubmr, uts;
1242 
1243         if (!sport->dma_chan_tx)
1244                 return;
1245 
1246         sport->tx_bytes = 0;
1247         dmaengine_terminate_all(sport->dma_chan_tx);
1248         if (sport->dma_is_txing) {
1249                 dma_unmap_sg(sport->port.dev, sgl, sport->dma_tx_nents,
1250                              DMA_TO_DEVICE);
1251                 temp = readl(sport->port.membase + UCR1);
1252                 temp &= ~UCR1_TDMAEN;
1253                 writel(temp, sport->port.membase + UCR1);
1254                 sport->dma_is_txing = false;
1255         }
1256 
1257         /*
1258          * According to the Reference Manual description of the UART SRST bit:
1259          * "Reset the transmit and receive state machines,
1260          * all FIFOs and register USR1, USR2, UBIR, UBMR, UBRC, URXD, UTXD
1261          * and UTS[6-3]". As we don't need to restore the old values from
1262          * USR1, USR2, URXD, UTXD, only save/restore the other four registers
1263          */
1264         ubir = readl(sport->port.membase + UBIR);
1265         ubmr = readl(sport->port.membase + UBMR);
1266         uts = readl(sport->port.membase + IMX21_UTS);
1267 
1268         temp = readl(sport->port.membase + UCR2);
1269         temp &= ~UCR2_SRST;
1270         writel(temp, sport->port.membase + UCR2);
1271 
1272         while (!(readl(sport->port.membase + UCR2) & UCR2_SRST) && (--i > 0))
1273                 udelay(1);
1274 
1275         /* Restore the registers */
1276         writel(ubir, sport->port.membase + UBIR);
1277         writel(ubmr, sport->port.membase + UBMR);
1278         writel(uts, sport->port.membase + IMX21_UTS);
1279 }
1280 
1281 static void
1282 imx_set_termios(struct uart_port *port, struct ktermios *termios,
1283                    struct ktermios *old)
1284 {
1285         struct imx_port *sport = (struct imx_port *)port;
1286         unsigned long flags;
1287         unsigned int ucr2, old_ucr1, old_ucr2, baud, quot;
1288         unsigned int old_csize = old ? old->c_cflag & CSIZE : CS8;
1289         unsigned int div, ufcr;
1290         unsigned long num, denom;
1291         uint64_t tdiv64;
1292 
1293         /*
1294          * We only support CS7 and CS8.
1295          */
1296         while ((termios->c_cflag & CSIZE) != CS7 &&
1297                (termios->c_cflag & CSIZE) != CS8) {
1298                 termios->c_cflag &= ~CSIZE;
1299                 termios->c_cflag |= old_csize;
1300                 old_csize = CS8;
1301         }
1302 
1303         if ((termios->c_cflag & CSIZE) == CS8)
1304                 ucr2 = UCR2_WS | UCR2_SRST | UCR2_IRTS;
1305         else
1306                 ucr2 = UCR2_SRST | UCR2_IRTS;
1307 
1308         if (termios->c_cflag & CRTSCTS) {
1309                 if (sport->have_rtscts) {
1310                         ucr2 &= ~UCR2_IRTS;
1311 
1312                         if (port->rs485.flags & SER_RS485_ENABLED) {
1313                                 /*
1314                                  * RTS is mandatory for rs485 operation, so keep
1315                                  * it under manual control and keep transmitter
1316                                  * disabled.
1317                                  */
1318                                 if (!(port->rs485.flags &
1319                                       SER_RS485_RTS_AFTER_SEND))
1320                                         ucr2 |= UCR2_CTS;
1321                         } else {
1322                                 ucr2 |= UCR2_CTSC;
1323                         }
1324                 } else {
1325                         termios->c_cflag &= ~CRTSCTS;
1326                 }
1327         } else if (port->rs485.flags & SER_RS485_ENABLED)
1328                 /* disable transmitter */
1329                 if (!(port->rs485.flags & SER_RS485_RTS_AFTER_SEND))
1330                         ucr2 |= UCR2_CTS;
1331 
1332         if (termios->c_cflag & CSTOPB)
1333                 ucr2 |= UCR2_STPB;
1334         if (termios->c_cflag & PARENB) {
1335                 ucr2 |= UCR2_PREN;
1336                 if (termios->c_cflag & PARODD)
1337                         ucr2 |= UCR2_PROE;
1338         }
1339 
1340         del_timer_sync(&sport->timer);
1341 
1342         /*
1343          * Ask the core to calculate the divisor for us.
1344          */
1345         baud = uart_get_baud_rate(port, termios, old, 50, port->uartclk / 16);
1346         quot = uart_get_divisor(port, baud);
1347 
1348         spin_lock_irqsave(&sport->port.lock, flags);
1349 
1350         sport->port.read_status_mask = 0;
1351         if (termios->c_iflag & INPCK)
1352                 sport->port.read_status_mask |= (URXD_FRMERR | URXD_PRERR);
1353         if (termios->c_iflag & (BRKINT | PARMRK))
1354                 sport->port.read_status_mask |= URXD_BRK;
1355 
1356         /*
1357          * Characters to ignore
1358          */
1359         sport->port.ignore_status_mask = 0;
1360         if (termios->c_iflag & IGNPAR)
1361                 sport->port.ignore_status_mask |= URXD_PRERR | URXD_FRMERR;
1362         if (termios->c_iflag & IGNBRK) {
1363                 sport->port.ignore_status_mask |= URXD_BRK;
1364                 /*
1365                  * If we're ignoring parity and break indicators,
1366                  * ignore overruns too (for real raw support).
1367                  */
1368                 if (termios->c_iflag & IGNPAR)
1369                         sport->port.ignore_status_mask |= URXD_OVRRUN;
1370         }
1371 
1372         if ((termios->c_cflag & CREAD) == 0)
1373                 sport->port.ignore_status_mask |= URXD_DUMMY_READ;
1374 
1375         /*
1376          * Update the per-port timeout.
1377          */
1378         uart_update_timeout(port, termios->c_cflag, baud);
1379 
1380         /*
1381          * disable interrupts and drain transmitter
1382          */
1383         old_ucr1 = readl(sport->port.membase + UCR1);
1384         writel(old_ucr1 & ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN),
1385                         sport->port.membase + UCR1);
1386 
1387         while (!(readl(sport->port.membase + USR2) & USR2_TXDC))
1388                 barrier();
1389 
1390         /* then, disable everything */
1391         old_ucr2 = readl(sport->port.membase + UCR2);
1392         writel(old_ucr2 & ~(UCR2_TXEN | UCR2_RXEN),
1393                         sport->port.membase + UCR2);
1394         old_ucr2 &= (UCR2_TXEN | UCR2_RXEN | UCR2_ATEN);
1395 
1396         /* custom-baudrate handling */
1397         div = sport->port.uartclk / (baud * 16);
1398         if (baud == 38400 && quot != div)
1399                 baud = sport->port.uartclk / (quot * 16);
1400 
1401         div = sport->port.uartclk / (baud * 16);
1402         if (div > 7)
1403                 div = 7;
1404         if (!div)
1405                 div = 1;
1406 
1407         rational_best_approximation(16 * div * baud, sport->port.uartclk,
1408                 1 << 16, 1 << 16, &num, &denom);
1409 
1410         tdiv64 = sport->port.uartclk;
1411         tdiv64 *= num;
1412         do_div(tdiv64, denom * 16 * div);
1413         tty_termios_encode_baud_rate(termios,
1414                                 (speed_t)tdiv64, (speed_t)tdiv64);
1415 
1416         num -= 1;
1417         denom -= 1;
1418 
1419         ufcr = readl(sport->port.membase + UFCR);
1420         ufcr = (ufcr & (~UFCR_RFDIV)) | UFCR_RFDIV_REG(div);
1421         if (sport->dte_mode)
1422                 ufcr |= UFCR_DCEDTE;
1423         writel(ufcr, sport->port.membase + UFCR);
1424 
1425         writel(num, sport->port.membase + UBIR);
1426         writel(denom, sport->port.membase + UBMR);
1427 
1428         if (!is_imx1_uart(sport))
1429                 writel(sport->port.uartclk / div / 1000,
1430                                 sport->port.membase + IMX21_ONEMS);
1431 
1432         writel(old_ucr1, sport->port.membase + UCR1);
1433 
1434         /* set the parity, stop bits and data size */
1435         writel(ucr2 | old_ucr2, sport->port.membase + UCR2);
1436 
1437         if (UART_ENABLE_MS(&sport->port, termios->c_cflag))
1438                 imx_enable_ms(&sport->port);
1439 
1440         spin_unlock_irqrestore(&sport->port.lock, flags);
1441 }
1442 
1443 static const char *imx_type(struct uart_port *port)
1444 {
1445         struct imx_port *sport = (struct imx_port *)port;
1446 
1447         return sport->port.type == PORT_IMX ? "IMX" : NULL;
1448 }
1449 
1450 /*
1451  * Configure/autoconfigure the port.
1452  */
1453 static void imx_config_port(struct uart_port *port, int flags)
1454 {
1455         struct imx_port *sport = (struct imx_port *)port;
1456 
1457         if (flags & UART_CONFIG_TYPE)
1458                 sport->port.type = PORT_IMX;
1459 }
1460 
1461 /*
1462  * Verify the new serial_struct (for TIOCSSERIAL).
1463  * The only change we allow are to the flags and type, and
1464  * even then only between PORT_IMX and PORT_UNKNOWN
1465  */
1466 static int
1467 imx_verify_port(struct uart_port *port, struct serial_struct *ser)
1468 {
1469         struct imx_port *sport = (struct imx_port *)port;
1470         int ret = 0;
1471 
1472         if (ser->type != PORT_UNKNOWN && ser->type != PORT_IMX)
1473                 ret = -EINVAL;
1474         if (sport->port.irq != ser->irq)
1475                 ret = -EINVAL;
1476         if (ser->io_type != UPIO_MEM)
1477                 ret = -EINVAL;
1478         if (sport->port.uartclk / 16 != ser->baud_base)
1479                 ret = -EINVAL;
1480         if (sport->port.mapbase != (unsigned long)ser->iomem_base)
1481                 ret = -EINVAL;
1482         if (sport->port.iobase != ser->port)
1483                 ret = -EINVAL;
1484         if (ser->hub6 != 0)
1485                 ret = -EINVAL;
1486         return ret;
1487 }
1488 
1489 #if defined(CONFIG_CONSOLE_POLL)
1490 
1491 static int imx_poll_init(struct uart_port *port)
1492 {
1493         struct imx_port *sport = (struct imx_port *)port;
1494         unsigned long flags;
1495         unsigned long temp;
1496         int retval;
1497 
1498         retval = clk_prepare_enable(sport->clk_ipg);
1499         if (retval)
1500                 return retval;
1501         retval = clk_prepare_enable(sport->clk_per);
1502         if (retval)
1503                 clk_disable_unprepare(sport->clk_ipg);
1504 
1505         imx_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT);
1506 
1507         spin_lock_irqsave(&sport->port.lock, flags);
1508 
1509         temp = readl(sport->port.membase + UCR1);
1510         if (is_imx1_uart(sport))
1511                 temp |= IMX1_UCR1_UARTCLKEN;
1512         temp |= UCR1_UARTEN | UCR1_RRDYEN;
1513         temp &= ~(UCR1_TXMPTYEN | UCR1_RTSDEN);
1514         writel(temp, sport->port.membase + UCR1);
1515 
1516         temp = readl(sport->port.membase + UCR2);
1517         temp |= UCR2_RXEN;
1518         writel(temp, sport->port.membase + UCR2);
1519 
1520         spin_unlock_irqrestore(&sport->port.lock, flags);
1521 
1522         return 0;
1523 }
1524 
1525 static int imx_poll_get_char(struct uart_port *port)
1526 {
1527         if (!(readl_relaxed(port->membase + USR2) & USR2_RDR))
1528                 return NO_POLL_CHAR;
1529 
1530         return readl_relaxed(port->membase + URXD0) & URXD_RX_DATA;
1531 }
1532 
1533 static void imx_poll_put_char(struct uart_port *port, unsigned char c)
1534 {
1535         unsigned int status;
1536 
1537         /* drain */
1538         do {
1539                 status = readl_relaxed(port->membase + USR1);
1540         } while (~status & USR1_TRDY);
1541 
1542         /* write */
1543         writel_relaxed(c, port->membase + URTX0);
1544 
1545         /* flush */
1546         do {
1547                 status = readl_relaxed(port->membase + USR2);
1548         } while (~status & USR2_TXDC);
1549 }
1550 #endif
1551 
1552 static int imx_rs485_config(struct uart_port *port,
1553                             struct serial_rs485 *rs485conf)
1554 {
1555         struct imx_port *sport = (struct imx_port *)port;
1556 
1557         /* unimplemented */
1558         rs485conf->delay_rts_before_send = 0;
1559         rs485conf->delay_rts_after_send = 0;
1560         rs485conf->flags |= SER_RS485_RX_DURING_TX;
1561 
1562         /* RTS is required to control the transmitter */
1563         if (!sport->have_rtscts)
1564                 rs485conf->flags &= ~SER_RS485_ENABLED;
1565 
1566         if (rs485conf->flags & SER_RS485_ENABLED) {
1567                 unsigned long temp;
1568 
1569                 /* disable transmitter */
1570                 temp = readl(sport->port.membase + UCR2);
1571                 temp &= ~UCR2_CTSC;
1572                 if (rs485conf->flags & SER_RS485_RTS_AFTER_SEND)
1573                         temp &= ~UCR2_CTS;
1574                 else
1575                         temp |= UCR2_CTS;
1576                 writel(temp, sport->port.membase + UCR2);
1577         }
1578 
1579         port->rs485 = *rs485conf;
1580 
1581         return 0;
1582 }
1583 
1584 static struct uart_ops imx_pops = {
1585         .tx_empty       = imx_tx_empty,
1586         .set_mctrl      = imx_set_mctrl,
1587         .get_mctrl      = imx_get_mctrl,
1588         .stop_tx        = imx_stop_tx,
1589         .start_tx       = imx_start_tx,
1590         .stop_rx        = imx_stop_rx,
1591         .enable_ms      = imx_enable_ms,
1592         .break_ctl      = imx_break_ctl,
1593         .startup        = imx_startup,
1594         .shutdown       = imx_shutdown,
1595         .flush_buffer   = imx_flush_buffer,
1596         .set_termios    = imx_set_termios,
1597         .type           = imx_type,
1598         .config_port    = imx_config_port,
1599         .verify_port    = imx_verify_port,
1600 #if defined(CONFIG_CONSOLE_POLL)
1601         .poll_init      = imx_poll_init,
1602         .poll_get_char  = imx_poll_get_char,
1603         .poll_put_char  = imx_poll_put_char,
1604 #endif
1605 };
1606 
1607 static struct imx_port *imx_ports[UART_NR];
1608 
1609 #ifdef CONFIG_SERIAL_IMX_CONSOLE
1610 static void imx_console_putchar(struct uart_port *port, int ch)
1611 {
1612         struct imx_port *sport = (struct imx_port *)port;
1613 
1614         while (readl(sport->port.membase + uts_reg(sport)) & UTS_TXFULL)
1615                 barrier();
1616 
1617         writel(ch, sport->port.membase + URTX0);
1618 }
1619 
1620 /*
1621  * Interrupts are disabled on entering
1622  */
1623 static void
1624 imx_console_write(struct console *co, const char *s, unsigned int count)
1625 {
1626         struct imx_port *sport = imx_ports[co->index];
1627         struct imx_port_ucrs old_ucr;
1628         unsigned int ucr1;
1629         unsigned long flags = 0;
1630         int locked = 1;
1631         int retval;
1632 
1633         retval = clk_enable(sport->clk_per);
1634         if (retval)
1635                 return;
1636         retval = clk_enable(sport->clk_ipg);
1637         if (retval) {
1638                 clk_disable(sport->clk_per);
1639                 return;
1640         }
1641 
1642         if (sport->port.sysrq)
1643                 locked = 0;
1644         else if (oops_in_progress)
1645                 locked = spin_trylock_irqsave(&sport->port.lock, flags);
1646         else
1647                 spin_lock_irqsave(&sport->port.lock, flags);
1648 
1649         /*
1650          *      First, save UCR1/2/3 and then disable interrupts
1651          */
1652         imx_port_ucrs_save(&sport->port, &old_ucr);
1653         ucr1 = old_ucr.ucr1;
1654 
1655         if (is_imx1_uart(sport))
1656                 ucr1 |= IMX1_UCR1_UARTCLKEN;
1657         ucr1 |= UCR1_UARTEN;
1658         ucr1 &= ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN);
1659 
1660         writel(ucr1, sport->port.membase + UCR1);
1661 
1662         writel(old_ucr.ucr2 | UCR2_TXEN, sport->port.membase + UCR2);
1663 
1664         uart_console_write(&sport->port, s, count, imx_console_putchar);
1665 
1666         /*
1667          *      Finally, wait for transmitter to become empty
1668          *      and restore UCR1/2/3
1669          */
1670         while (!(readl(sport->port.membase + USR2) & USR2_TXDC));
1671 
1672         imx_port_ucrs_restore(&sport->port, &old_ucr);
1673 
1674         if (locked)
1675                 spin_unlock_irqrestore(&sport->port.lock, flags);
1676 
1677         clk_disable(sport->clk_ipg);
1678         clk_disable(sport->clk_per);
1679 }
1680 
1681 /*
1682  * If the port was already initialised (eg, by a boot loader),
1683  * try to determine the current setup.
1684  */
1685 static void __init
1686 imx_console_get_options(struct imx_port *sport, int *baud,
1687                            int *parity, int *bits)
1688 {
1689 
1690         if (readl(sport->port.membase + UCR1) & UCR1_UARTEN) {
1691                 /* ok, the port was enabled */
1692                 unsigned int ucr2, ubir, ubmr, uartclk;
1693                 unsigned int baud_raw;
1694                 unsigned int ucfr_rfdiv;
1695 
1696                 ucr2 = readl(sport->port.membase + UCR2);
1697 
1698                 *parity = 'n';
1699                 if (ucr2 & UCR2_PREN) {
1700                         if (ucr2 & UCR2_PROE)
1701                                 *parity = 'o';
1702                         else
1703                                 *parity = 'e';
1704                 }
1705 
1706                 if (ucr2 & UCR2_WS)
1707                         *bits = 8;
1708                 else
1709                         *bits = 7;
1710 
1711                 ubir = readl(sport->port.membase + UBIR) & 0xffff;
1712                 ubmr = readl(sport->port.membase + UBMR) & 0xffff;
1713 
1714                 ucfr_rfdiv = (readl(sport->port.membase + UFCR) & UFCR_RFDIV) >> 7;
1715                 if (ucfr_rfdiv == 6)
1716                         ucfr_rfdiv = 7;
1717                 else
1718                         ucfr_rfdiv = 6 - ucfr_rfdiv;
1719 
1720                 uartclk = clk_get_rate(sport->clk_per);
1721                 uartclk /= ucfr_rfdiv;
1722 
1723                 {       /*
1724                          * The next code provides exact computation of
1725                          *   baud_raw = round(((uartclk/16) * (ubir + 1)) / (ubmr + 1))
1726                          * without need of float support or long long division,
1727                          * which would be required to prevent 32bit arithmetic overflow
1728                          */
1729                         unsigned int mul = ubir + 1;
1730                         unsigned int div = 16 * (ubmr + 1);
1731                         unsigned int rem = uartclk % div;
1732 
1733                         baud_raw = (uartclk / div) * mul;
1734                         baud_raw += (rem * mul + div / 2) / div;
1735                         *baud = (baud_raw + 50) / 100 * 100;
1736                 }
1737 
1738                 if (*baud != baud_raw)
1739                         pr_info("Console IMX rounded baud rate from %d to %d\n",
1740                                 baud_raw, *baud);
1741         }
1742 }
1743 
1744 static int __init
1745 imx_console_setup(struct console *co, char *options)
1746 {
1747         struct imx_port *sport;
1748         int baud = 9600;
1749         int bits = 8;
1750         int parity = 'n';
1751         int flow = 'n';
1752         int retval;
1753 
1754         /*
1755          * Check whether an invalid uart number has been specified, and
1756          * if so, search for the first available port that does have
1757          * console support.
1758          */
1759         if (co->index == -1 || co->index >= ARRAY_SIZE(imx_ports))
1760                 co->index = 0;
1761         sport = imx_ports[co->index];
1762         if (sport == NULL)
1763                 return -ENODEV;
1764 
1765         /* For setting the registers, we only need to enable the ipg clock. */
1766         retval = clk_prepare_enable(sport->clk_ipg);
1767         if (retval)
1768                 goto error_console;
1769 
1770         if (options)
1771                 uart_parse_options(options, &baud, &parity, &bits, &flow);
1772         else
1773                 imx_console_get_options(sport, &baud, &parity, &bits);
1774 
1775         imx_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT);
1776 
1777         retval = uart_set_options(&sport->port, co, baud, parity, bits, flow);
1778 
1779         clk_disable(sport->clk_ipg);
1780         if (retval) {
1781                 clk_unprepare(sport->clk_ipg);
1782                 goto error_console;
1783         }
1784 
1785         retval = clk_prepare(sport->clk_per);
1786         if (retval)
1787                 clk_disable_unprepare(sport->clk_ipg);
1788 
1789 error_console:
1790         return retval;
1791 }
1792 
1793 static struct uart_driver imx_reg;
1794 static struct console imx_console = {
1795         .name           = DEV_NAME,
1796         .write          = imx_console_write,
1797         .device         = uart_console_device,
1798         .setup          = imx_console_setup,
1799         .flags          = CON_PRINTBUFFER,
1800         .index          = -1,
1801         .data           = &imx_reg,
1802 };
1803 
1804 #define IMX_CONSOLE     &imx_console
1805 
1806 #ifdef CONFIG_OF
1807 static void imx_console_early_putchar(struct uart_port *port, int ch)
1808 {
1809         while (readl_relaxed(port->membase + IMX21_UTS) & UTS_TXFULL)
1810                 cpu_relax();
1811 
1812         writel_relaxed(ch, port->membase + URTX0);
1813 }
1814 
1815 static void imx_console_early_write(struct console *con, const char *s,
1816                                     unsigned count)
1817 {
1818         struct earlycon_device *dev = con->data;
1819 
1820         uart_console_write(&dev->port, s, count, imx_console_early_putchar);
1821 }
1822 
1823 static int __init
1824 imx_console_early_setup(struct earlycon_device *dev, const char *opt)
1825 {
1826         if (!dev->port.membase)
1827                 return -ENODEV;
1828 
1829         dev->con->write = imx_console_early_write;
1830 
1831         return 0;
1832 }
1833 OF_EARLYCON_DECLARE(ec_imx6q, "fsl,imx6q-uart", imx_console_early_setup);
1834 OF_EARLYCON_DECLARE(ec_imx21, "fsl,imx21-uart", imx_console_early_setup);
1835 #endif
1836 
1837 #else
1838 #define IMX_CONSOLE     NULL
1839 #endif
1840 
1841 static struct uart_driver imx_reg = {
1842         .owner          = THIS_MODULE,
1843         .driver_name    = DRIVER_NAME,
1844         .dev_name       = DEV_NAME,
1845         .major          = SERIAL_IMX_MAJOR,
1846         .minor          = MINOR_START,
1847         .nr             = ARRAY_SIZE(imx_ports),
1848         .cons           = IMX_CONSOLE,
1849 };
1850 
1851 #ifdef CONFIG_OF
1852 /*
1853  * This function returns 1 iff pdev isn't a device instatiated by dt, 0 iff it
1854  * could successfully get all information from dt or a negative errno.
1855  */
1856 static int serial_imx_probe_dt(struct imx_port *sport,
1857                 struct platform_device *pdev)
1858 {
1859         struct device_node *np = pdev->dev.of_node;
1860         const struct of_device_id *of_id =
1861                         of_match_device(imx_uart_dt_ids, &pdev->dev);
1862         int ret;
1863 
1864         if (!np)
1865                 /* no device tree device */
1866                 return 1;
1867 
1868         ret = of_alias_get_id(np, "serial");
1869         if (ret < 0) {
1870                 dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
1871                 return ret;
1872         }
1873         sport->port.line = ret;
1874 
1875         if (of_get_property(np, "fsl,uart-has-rtscts", NULL))
1876                 sport->have_rtscts = 1;
1877 
1878         if (of_get_property(np, "fsl,dte-mode", NULL))
1879                 sport->dte_mode = 1;
1880 
1881         sport->devdata = of_id->data;
1882 
1883         return 0;
1884 }
1885 #else
1886 static inline int serial_imx_probe_dt(struct imx_port *sport,
1887                 struct platform_device *pdev)
1888 {
1889         return 1;
1890 }
1891 #endif
1892 
1893 static void serial_imx_probe_pdata(struct imx_port *sport,
1894                 struct platform_device *pdev)
1895 {
1896         struct imxuart_platform_data *pdata = dev_get_platdata(&pdev->dev);
1897 
1898         sport->port.line = pdev->id;
1899         sport->devdata = (struct imx_uart_data  *) pdev->id_entry->driver_data;
1900 
1901         if (!pdata)
1902                 return;
1903 
1904         if (pdata->flags & IMXUART_HAVE_RTSCTS)
1905                 sport->have_rtscts = 1;
1906 }
1907 
1908 static int serial_imx_probe(struct platform_device *pdev)
1909 {
1910         struct imx_port *sport;
1911         void __iomem *base;
1912         int ret = 0, reg;
1913         struct resource *res;
1914         int txirq, rxirq, rtsirq;
1915 
1916         sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL);
1917         if (!sport)
1918                 return -ENOMEM;
1919 
1920         ret = serial_imx_probe_dt(sport, pdev);
1921         if (ret > 0)
1922                 serial_imx_probe_pdata(sport, pdev);
1923         else if (ret < 0)
1924                 return ret;
1925 
1926         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1927         base = devm_ioremap_resource(&pdev->dev, res);
1928         if (IS_ERR(base))
1929                 return PTR_ERR(base);
1930 
1931         rxirq = platform_get_irq(pdev, 0);
1932         txirq = platform_get_irq(pdev, 1);
1933         rtsirq = platform_get_irq(pdev, 2);
1934 
1935         sport->port.dev = &pdev->dev;
1936         sport->port.mapbase = res->start;
1937         sport->port.membase = base;
1938         sport->port.type = PORT_IMX,
1939         sport->port.iotype = UPIO_MEM;
1940         sport->port.irq = rxirq;
1941         sport->port.fifosize = 32;
1942         sport->port.ops = &imx_pops;
1943         sport->port.rs485_config = imx_rs485_config;
1944         sport->port.rs485.flags =
1945                 SER_RS485_RTS_ON_SEND | SER_RS485_RX_DURING_TX;
1946         sport->port.flags = UPF_BOOT_AUTOCONF;
1947         init_timer(&sport->timer);
1948         sport->timer.function = imx_timeout;
1949         sport->timer.data     = (unsigned long)sport;
1950 
1951         sport->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
1952         if (IS_ERR(sport->clk_ipg)) {
1953                 ret = PTR_ERR(sport->clk_ipg);
1954                 dev_err(&pdev->dev, "failed to get ipg clk: %d\n", ret);
1955                 return ret;
1956         }
1957 
1958         sport->clk_per = devm_clk_get(&pdev->dev, "per");
1959         if (IS_ERR(sport->clk_per)) {
1960                 ret = PTR_ERR(sport->clk_per);
1961                 dev_err(&pdev->dev, "failed to get per clk: %d\n", ret);
1962                 return ret;
1963         }
1964 
1965         sport->port.uartclk = clk_get_rate(sport->clk_per);
1966 
1967         /* For register access, we only need to enable the ipg clock. */
1968         ret = clk_prepare_enable(sport->clk_ipg);
1969         if (ret)
1970                 return ret;
1971 
1972         /* Disable interrupts before requesting them */
1973         reg = readl_relaxed(sport->port.membase + UCR1);
1974         reg &= ~(UCR1_ADEN | UCR1_TRDYEN | UCR1_IDEN | UCR1_RRDYEN |
1975                  UCR1_TXMPTYEN | UCR1_RTSDEN);
1976         writel_relaxed(reg, sport->port.membase + UCR1);
1977 
1978         clk_disable_unprepare(sport->clk_ipg);
1979 
1980         /*
1981          * Allocate the IRQ(s) i.MX1 has three interrupts whereas later
1982          * chips only have one interrupt.
1983          */
1984         if (txirq > 0) {
1985                 ret = devm_request_irq(&pdev->dev, rxirq, imx_rxint, 0,
1986                                        dev_name(&pdev->dev), sport);
1987                 if (ret)
1988                         return ret;
1989 
1990                 ret = devm_request_irq(&pdev->dev, txirq, imx_txint, 0,
1991                                        dev_name(&pdev->dev), sport);
1992                 if (ret)
1993                         return ret;
1994         } else {
1995                 ret = devm_request_irq(&pdev->dev, rxirq, imx_int, 0,
1996                                        dev_name(&pdev->dev), sport);
1997                 if (ret)
1998                         return ret;
1999         }
2000 
2001         imx_ports[sport->port.line] = sport;
2002 
2003         platform_set_drvdata(pdev, sport);
2004 
2005         return uart_add_one_port(&imx_reg, &sport->port);
2006 }
2007 
2008 static int serial_imx_remove(struct platform_device *pdev)
2009 {
2010         struct imx_port *sport = platform_get_drvdata(pdev);
2011 
2012         return uart_remove_one_port(&imx_reg, &sport->port);
2013 }
2014 
2015 static void serial_imx_restore_context(struct imx_port *sport)
2016 {
2017         if (!sport->context_saved)
2018                 return;
2019 
2020         writel(sport->saved_reg[4], sport->port.membase + UFCR);
2021         writel(sport->saved_reg[5], sport->port.membase + UESC);
2022         writel(sport->saved_reg[6], sport->port.membase + UTIM);
2023         writel(sport->saved_reg[7], sport->port.membase + UBIR);
2024         writel(sport->saved_reg[8], sport->port.membase + UBMR);
2025         writel(sport->saved_reg[9], sport->port.membase + IMX21_UTS);
2026         writel(sport->saved_reg[0], sport->port.membase + UCR1);
2027         writel(sport->saved_reg[1] | UCR2_SRST, sport->port.membase + UCR2);
2028         writel(sport->saved_reg[2], sport->port.membase + UCR3);
2029         writel(sport->saved_reg[3], sport->port.membase + UCR4);
2030         sport->context_saved = false;
2031 }
2032 
2033 static void serial_imx_save_context(struct imx_port *sport)
2034 {
2035         /* Save necessary regs */
2036         sport->saved_reg[0] = readl(sport->port.membase + UCR1);
2037         sport->saved_reg[1] = readl(sport->port.membase + UCR2);
2038         sport->saved_reg[2] = readl(sport->port.membase + UCR3);
2039         sport->saved_reg[3] = readl(sport->port.membase + UCR4);
2040         sport->saved_reg[4] = readl(sport->port.membase + UFCR);
2041         sport->saved_reg[5] = readl(sport->port.membase + UESC);
2042         sport->saved_reg[6] = readl(sport->port.membase + UTIM);
2043         sport->saved_reg[7] = readl(sport->port.membase + UBIR);
2044         sport->saved_reg[8] = readl(sport->port.membase + UBMR);
2045         sport->saved_reg[9] = readl(sport->port.membase + IMX21_UTS);
2046         sport->context_saved = true;
2047 }
2048 
2049 static void serial_imx_enable_wakeup(struct imx_port *sport, bool on)
2050 {
2051         unsigned int val;
2052 
2053         val = readl(sport->port.membase + UCR3);
2054         if (on)
2055                 val |= UCR3_AWAKEN;
2056         else
2057                 val &= ~UCR3_AWAKEN;
2058         writel(val, sport->port.membase + UCR3);
2059 
2060         val = readl(sport->port.membase + UCR1);
2061         if (on)
2062                 val |= UCR1_RTSDEN;
2063         else
2064                 val &= ~UCR1_RTSDEN;
2065         writel(val, sport->port.membase + UCR1);
2066 }
2067 
2068 static int imx_serial_port_suspend_noirq(struct device *dev)
2069 {
2070         struct platform_device *pdev = to_platform_device(dev);
2071         struct imx_port *sport = platform_get_drvdata(pdev);
2072         int ret;
2073 
2074         ret = clk_enable(sport->clk_ipg);
2075         if (ret)
2076                 return ret;
2077 
2078         serial_imx_save_context(sport);
2079 
2080         clk_disable(sport->clk_ipg);
2081 
2082         return 0;
2083 }
2084 
2085 static int imx_serial_port_resume_noirq(struct device *dev)
2086 {
2087         struct platform_device *pdev = to_platform_device(dev);
2088         struct imx_port *sport = platform_get_drvdata(pdev);
2089         int ret;
2090 
2091         ret = clk_enable(sport->clk_ipg);
2092         if (ret)
2093                 return ret;
2094 
2095         serial_imx_restore_context(sport);
2096 
2097         clk_disable(sport->clk_ipg);
2098 
2099         return 0;
2100 }
2101 
2102 static int imx_serial_port_suspend(struct device *dev)
2103 {
2104         struct platform_device *pdev = to_platform_device(dev);
2105         struct imx_port *sport = platform_get_drvdata(pdev);
2106 
2107         /* enable wakeup from i.MX UART */
2108         serial_imx_enable_wakeup(sport, true);
2109 
2110         uart_suspend_port(&imx_reg, &sport->port);
2111 
2112         return 0;
2113 }
2114 
2115 static int imx_serial_port_resume(struct device *dev)
2116 {
2117         struct platform_device *pdev = to_platform_device(dev);
2118         struct imx_port *sport = platform_get_drvdata(pdev);
2119 
2120         /* disable wakeup from i.MX UART */
2121         serial_imx_enable_wakeup(sport, false);
2122 
2123         uart_resume_port(&imx_reg, &sport->port);
2124 
2125         return 0;
2126 }
2127 
2128 static const struct dev_pm_ops imx_serial_port_pm_ops = {
2129         .suspend_noirq = imx_serial_port_suspend_noirq,
2130         .resume_noirq = imx_serial_port_resume_noirq,
2131         .suspend = imx_serial_port_suspend,
2132         .resume = imx_serial_port_resume,
2133 };
2134 
2135 static struct platform_driver serial_imx_driver = {
2136         .probe          = serial_imx_probe,
2137         .remove         = serial_imx_remove,
2138 
2139         .id_table       = imx_uart_devtype,
2140         .driver         = {
2141                 .name   = "imx-uart",
2142                 .of_match_table = imx_uart_dt_ids,
2143                 .pm     = &imx_serial_port_pm_ops,
2144         },
2145 };
2146 
2147 static int __init imx_serial_init(void)
2148 {
2149         int ret = uart_register_driver(&imx_reg);
2150 
2151         if (ret)
2152                 return ret;
2153 
2154         ret = platform_driver_register(&serial_imx_driver);
2155         if (ret != 0)
2156                 uart_unregister_driver(&imx_reg);
2157 
2158         return ret;
2159 }
2160 
2161 static void __exit imx_serial_exit(void)
2162 {
2163         platform_driver_unregister(&serial_imx_driver);
2164         uart_unregister_driver(&imx_reg);
2165 }
2166 
2167 module_init(imx_serial_init);
2168 module_exit(imx_serial_exit);
2169 
2170 MODULE_AUTHOR("Sascha Hauer");
2171 MODULE_DESCRIPTION("IMX generic serial port driver");
2172 MODULE_LICENSE("GPL");
2173 MODULE_ALIAS("platform:imx-uart");
2174 

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