1 // SPDX-License-Identifier: GPL-2.0+
3 * Driver for Motorola/Freescale IMX serial ports
5 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
7 * Author: Sascha Hauer <sascha@saschahauer.de>
8 * Copyright (C) 2004 Pengutronix
11 #include <linux/module.h>
12 #include <linux/ioport.h>
13 #include <linux/init.h>
14 #include <linux/console.h>
15 #include <linux/sysrq.h>
16 #include <linux/platform_device.h>
17 #include <linux/tty.h>
18 #include <linux/tty_flip.h>
19 #include <linux/serial_core.h>
20 #include <linux/serial.h>
21 #include <linux/clk.h>
22 #include <linux/delay.h>
23 #include <linux/ktime.h>
24 #include <linux/pinctrl/consumer.h>
25 #include <linux/rational.h>
26 #include <linux/slab.h>
29 #include <linux/dma-mapping.h>
32 #include <linux/dma/imx-dma.h>
34 #include "serial_mctrl_gpio.h"
36 /* Register definitions */
37 #define URXD0 0x0 /* Receiver Register */
38 #define URTX0 0x40 /* Transmitter Register */
39 #define UCR1 0x80 /* Control Register 1 */
40 #define UCR2 0x84 /* Control Register 2 */
41 #define UCR3 0x88 /* Control Register 3 */
42 #define UCR4 0x8c /* Control Register 4 */
43 #define UFCR 0x90 /* FIFO Control Register */
44 #define USR1 0x94 /* Status Register 1 */
45 #define USR2 0x98 /* Status Register 2 */
46 #define UESC 0x9c /* Escape Character Register */
47 #define UTIM 0xa0 /* Escape Timer Register */
48 #define UBIR 0xa4 /* BRM Incremental Register */
49 #define UBMR 0xa8 /* BRM Modulator Register */
50 #define UBRC 0xac /* Baud Rate Count Register */
51 #define IMX21_ONEMS 0xb0 /* One Millisecond register */
52 #define IMX1_UTS 0xd0 /* UART Test Register on i.mx1 */
53 #define IMX21_UTS 0xb4 /* UART Test Register on all other i.mx*/
55 /* UART Control Register Bit Fields.*/
56 #define URXD_DUMMY_READ (1<<16)
57 #define URXD_CHARRDY (1<<15)
58 #define URXD_ERR (1<<14)
59 #define URXD_OVRRUN (1<<13)
60 #define URXD_FRMERR (1<<12)
61 #define URXD_BRK (1<<11)
62 #define URXD_PRERR (1<<10)
63 #define URXD_RX_DATA (0xFF<<0)
64 #define UCR1_ADEN (1<<15) /* Auto detect interrupt */
65 #define UCR1_ADBR (1<<14) /* Auto detect baud rate */
66 #define UCR1_TRDYEN (1<<13) /* Transmitter ready interrupt enable */
67 #define UCR1_IDEN (1<<12) /* Idle condition interrupt */
68 #define UCR1_ICD_REG(x) (((x) & 3) << 10) /* idle condition detect */
69 #define UCR1_RRDYEN (1<<9) /* Recv ready interrupt enable */
70 #define UCR1_RXDMAEN (1<<8) /* Recv ready DMA enable */
71 #define UCR1_IREN (1<<7) /* Infrared interface enable */
72 #define UCR1_TXMPTYEN (1<<6) /* Transimitter empty interrupt enable */
73 #define UCR1_RTSDEN (1<<5) /* RTS delta interrupt enable */
74 #define UCR1_SNDBRK (1<<4) /* Send break */
75 #define UCR1_TXDMAEN (1<<3) /* Transmitter ready DMA enable */
76 #define IMX1_UCR1_UARTCLKEN (1<<2) /* UART clock enabled, i.mx1 only */
77 #define UCR1_ATDMAEN (1<<2) /* Aging DMA Timer Enable */
78 #define UCR1_DOZE (1<<1) /* Doze */
79 #define UCR1_UARTEN (1<<0) /* UART enabled */
80 #define UCR2_ESCI (1<<15) /* Escape seq interrupt enable */
81 #define UCR2_IRTS (1<<14) /* Ignore RTS pin */
82 #define UCR2_CTSC (1<<13) /* CTS pin control */
83 #define UCR2_CTS (1<<12) /* Clear to send */
84 #define UCR2_ESCEN (1<<11) /* Escape enable */
85 #define UCR2_PREN (1<<8) /* Parity enable */
86 #define UCR2_PROE (1<<7) /* Parity odd/even */
87 #define UCR2_STPB (1<<6) /* Stop */
88 #define UCR2_WS (1<<5) /* Word size */
89 #define UCR2_RTSEN (1<<4) /* Request to send interrupt enable */
90 #define UCR2_ATEN (1<<3) /* Aging Timer Enable */
91 #define UCR2_TXEN (1<<2) /* Transmitter enabled */
92 #define UCR2_RXEN (1<<1) /* Receiver enabled */
93 #define UCR2_SRST (1<<0) /* SW reset */
94 #define UCR3_DTREN (1<<13) /* DTR interrupt enable */
95 #define UCR3_PARERREN (1<<12) /* Parity enable */
96 #define UCR3_FRAERREN (1<<11) /* Frame error interrupt enable */
97 #define UCR3_DSR (1<<10) /* Data set ready */
98 #define UCR3_DCD (1<<9) /* Data carrier detect */
99 #define UCR3_RI (1<<8) /* Ring indicator */
100 #define UCR3_ADNIMP (1<<7) /* Autobaud Detection Not Improved */
101 #define UCR3_RXDSEN (1<<6) /* Receive status interrupt enable */
102 #define UCR3_AIRINTEN (1<<5) /* Async IR wake interrupt enable */
103 #define UCR3_AWAKEN (1<<4) /* Async wake interrupt enable */
104 #define UCR3_DTRDEN (1<<3) /* Data Terminal Ready Delta Enable. */
105 #define IMX21_UCR3_RXDMUXSEL (1<<2) /* RXD Muxed Input Select */
106 #define UCR3_INVT (1<<1) /* Inverted Infrared transmission */
107 #define UCR3_BPEN (1<<0) /* Preset registers enable */
108 #define UCR4_CTSTL_SHF 10 /* CTS trigger level shift */
109 #define UCR4_CTSTL_MASK 0x3F /* CTS trigger is 6 bits wide */
110 #define UCR4_INVR (1<<9) /* Inverted infrared reception */
111 #define UCR4_ENIRI (1<<8) /* Serial infrared interrupt enable */
112 #define UCR4_WKEN (1<<7) /* Wake interrupt enable */
113 #define UCR4_REF16 (1<<6) /* Ref freq 16 MHz */
114 #define UCR4_IDDMAEN (1<<6) /* DMA IDLE Condition Detected */
115 #define UCR4_IRSC (1<<5) /* IR special case */
116 #define UCR4_TCEN (1<<3) /* Transmit complete interrupt enable */
117 #define UCR4_BKEN (1<<2) /* Break condition interrupt enable */
118 #define UCR4_OREN (1<<1) /* Receiver overrun interrupt enable */
119 #define UCR4_DREN (1<<0) /* Recv data ready interrupt enable */
120 #define UFCR_RXTL_SHF 0 /* Receiver trigger level shift */
121 #define UFCR_DCEDTE (1<<6) /* DCE/DTE mode select */
122 #define UFCR_RFDIV (7<<7) /* Reference freq divider mask */
123 #define UFCR_RFDIV_REG(x) (((x) < 7 ? 6 - (x) : 6) << 7)
124 #define UFCR_TXTL_SHF 10 /* Transmitter trigger level shift */
125 #define USR1_PARITYERR (1<<15) /* Parity error interrupt flag */
126 #define USR1_RTSS (1<<14) /* RTS pin status */
127 #define USR1_TRDY (1<<13) /* Transmitter ready interrupt/dma flag */
128 #define USR1_RTSD (1<<12) /* RTS delta */
129 #define USR1_ESCF (1<<11) /* Escape seq interrupt flag */
130 #define USR1_FRAMERR (1<<10) /* Frame error interrupt flag */
131 #define USR1_RRDY (1<<9) /* Receiver ready interrupt/dma flag */
132 #define USR1_AGTIM (1<<8) /* Ageing timer interrupt flag */
133 #define USR1_DTRD (1<<7) /* DTR Delta */
134 #define USR1_RXDS (1<<6) /* Receiver idle interrupt flag */
135 #define USR1_AIRINT (1<<5) /* Async IR wake interrupt flag */
136 #define USR1_AWAKE (1<<4) /* Aysnc wake interrupt flag */
137 #define USR2_ADET (1<<15) /* Auto baud rate detect complete */
138 #define USR2_TXFE (1<<14) /* Transmit buffer FIFO empty */
139 #define USR2_DTRF (1<<13) /* DTR edge interrupt flag */
140 #define USR2_IDLE (1<<12) /* Idle condition */
141 #define USR2_RIDELT (1<<10) /* Ring Interrupt Delta */
142 #define USR2_RIIN (1<<9) /* Ring Indicator Input */
143 #define USR2_IRINT (1<<8) /* Serial infrared interrupt flag */
144 #define USR2_WAKE (1<<7) /* Wake */
145 #define USR2_DCDIN (1<<5) /* Data Carrier Detect Input */
146 #define USR2_RTSF (1<<4) /* RTS edge interrupt flag */
147 #define USR2_TXDC (1<<3) /* Transmitter complete */
148 #define USR2_BRCD (1<<2) /* Break condition */
149 #define USR2_ORE (1<<1) /* Overrun error */
150 #define USR2_RDR (1<<0) /* Recv data ready */
151 #define UTS_FRCPERR (1<<13) /* Force parity error */
152 #define UTS_LOOP (1<<12) /* Loop tx and rx */
153 #define UTS_TXEMPTY (1<<6) /* TxFIFO empty */
154 #define UTS_RXEMPTY (1<<5) /* RxFIFO empty */
155 #define UTS_TXFULL (1<<4) /* TxFIFO full */
156 #define UTS_RXFULL (1<<3) /* RxFIFO full */
157 #define UTS_SOFTRST (1<<0) /* Software reset */
159 /* We've been assigned a range on the "Low-density serial ports" major */
160 #define SERIAL_IMX_MAJOR 207
161 #define MINOR_START 16
162 #define DEV_NAME "ttymxc"
165 * This determines how often we check the modem status signals
166 * for any change. They generally aren't connected to an IRQ
167 * so we have to poll them. We also check immediately before
168 * filling the TX fifo incase CTS has been dropped.
170 #define MCTRL_TIMEOUT (250*HZ/1000)
172 #define DRIVER_NAME "IMX-uart"
176 /* i.MX21 type uart runs on all i.mx except i.MX1 and i.MX6q */
182 /* device type dependent stuff */
183 struct imx_uart_data {
185 enum imx_uart_type devtype;
196 struct uart_port port;
197 struct timer_list timer;
198 unsigned int old_status;
199 unsigned int have_rtscts:1;
200 unsigned int have_rtsgpio:1;
201 unsigned int dte_mode:1;
202 unsigned int inverted_tx:1;
203 unsigned int inverted_rx:1;
206 const struct imx_uart_data *devdata;
208 struct mctrl_gpios *gpios;
210 /* counter to stop 0xff flood */
214 unsigned int dma_is_enabled:1;
215 unsigned int dma_is_rxing:1;
216 unsigned int dma_is_txing:1;
217 struct dma_chan *dma_chan_rx, *dma_chan_tx;
218 struct scatterlist rx_sgl, tx_sgl[2];
220 struct circ_buf rx_ring;
221 unsigned int rx_buf_size;
222 unsigned int rx_period_length;
223 unsigned int rx_periods;
224 dma_cookie_t rx_cookie;
225 unsigned int tx_bytes;
226 unsigned int dma_tx_nents;
227 unsigned int saved_reg[10];
230 enum imx_tx_state tx_state;
231 struct hrtimer trigger_start_tx;
232 struct hrtimer trigger_stop_tx;
235 struct imx_port_ucrs {
241 static const struct imx_uart_data imx_uart_imx1_devdata = {
243 .devtype = IMX1_UART,
246 static const struct imx_uart_data imx_uart_imx21_devdata = {
247 .uts_reg = IMX21_UTS,
248 .devtype = IMX21_UART,
251 static const struct of_device_id imx_uart_dt_ids[] = {
253 * For reasons unknown to me, some UART devices (e.g. imx6ul's) are
254 * compatible to fsl,imx6q-uart, but not fsl,imx21-uart, while the
255 * original imx6q's UART is compatible to fsl,imx21-uart. This driver
256 * doesn't make any distinction between these two variants.
258 { .compatible = "fsl,imx6q-uart", .data = &imx_uart_imx21_devdata, },
259 { .compatible = "fsl,imx1-uart", .data = &imx_uart_imx1_devdata, },
260 { .compatible = "fsl,imx21-uart", .data = &imx_uart_imx21_devdata, },
263 MODULE_DEVICE_TABLE(of, imx_uart_dt_ids);
265 static inline void imx_uart_writel(struct imx_port *sport, u32 val, u32 offset)
267 writel(val, sport->port.membase + offset);
270 static inline u32 imx_uart_readl(struct imx_port *sport, u32 offset)
272 return readl(sport->port.membase + offset);
275 static inline unsigned imx_uart_uts_reg(struct imx_port *sport)
277 return sport->devdata->uts_reg;
280 static inline int imx_uart_is_imx1(struct imx_port *sport)
282 return sport->devdata->devtype == IMX1_UART;
286 * Save and restore functions for UCR1, UCR2 and UCR3 registers
288 #if IS_ENABLED(CONFIG_SERIAL_IMX_CONSOLE)
289 static void imx_uart_ucrs_save(struct imx_port *sport,
290 struct imx_port_ucrs *ucr)
292 /* save control registers */
293 ucr->ucr1 = imx_uart_readl(sport, UCR1);
294 ucr->ucr2 = imx_uart_readl(sport, UCR2);
295 ucr->ucr3 = imx_uart_readl(sport, UCR3);
298 static void imx_uart_ucrs_restore(struct imx_port *sport,
299 struct imx_port_ucrs *ucr)
301 /* restore control registers */
302 imx_uart_writel(sport, ucr->ucr1, UCR1);
303 imx_uart_writel(sport, ucr->ucr2, UCR2);
304 imx_uart_writel(sport, ucr->ucr3, UCR3);
308 /* called with port.lock taken and irqs caller dependent */
309 static void imx_uart_rts_active(struct imx_port *sport, u32 *ucr2)
311 *ucr2 &= ~(UCR2_CTSC | UCR2_CTS);
313 mctrl_gpio_set(sport->gpios, sport->port.mctrl | TIOCM_RTS);
316 /* called with port.lock taken and irqs caller dependent */
317 static void imx_uart_rts_inactive(struct imx_port *sport, u32 *ucr2)
322 mctrl_gpio_set(sport->gpios, sport->port.mctrl & ~TIOCM_RTS);
325 static void start_hrtimer_ms(struct hrtimer *hrt, unsigned long msec)
327 hrtimer_start(hrt, ms_to_ktime(msec), HRTIMER_MODE_REL);
330 /* called with port.lock taken and irqs off */
331 static void imx_uart_soft_reset(struct imx_port *sport)
334 u32 ucr2, ubir, ubmr, uts;
337 * According to the Reference Manual description of the UART SRST bit:
339 * "Reset the transmit and receive state machines,
340 * all FIFOs and register USR1, USR2, UBIR, UBMR, UBRC, URXD, UTXD
343 * We don't need to restore the old values from USR1, USR2, URXD and
344 * UTXD. UBRC is read only, so only save/restore the other three
347 ubir = imx_uart_readl(sport, UBIR);
348 ubmr = imx_uart_readl(sport, UBMR);
349 uts = imx_uart_readl(sport, IMX21_UTS);
351 ucr2 = imx_uart_readl(sport, UCR2);
352 imx_uart_writel(sport, ucr2 & ~UCR2_SRST, UCR2);
354 while (!(imx_uart_readl(sport, UCR2) & UCR2_SRST) && (--i > 0))
357 /* Restore the registers */
358 imx_uart_writel(sport, ubir, UBIR);
359 imx_uart_writel(sport, ubmr, UBMR);
360 imx_uart_writel(sport, uts, IMX21_UTS);
362 sport->idle_counter = 0;
365 static void imx_uart_disable_loopback_rs485(struct imx_port *sport)
369 /* See SER_RS485_ENABLED/UTS_LOOP comment in imx_uart_probe() */
370 uts = imx_uart_readl(sport, imx_uart_uts_reg(sport));
372 imx_uart_writel(sport, uts, imx_uart_uts_reg(sport));
375 /* called with port.lock taken and irqs off */
376 static void imx_uart_start_rx(struct uart_port *port)
378 struct imx_port *sport = (struct imx_port *)port;
379 unsigned int ucr1, ucr2;
381 ucr1 = imx_uart_readl(sport, UCR1);
382 ucr2 = imx_uart_readl(sport, UCR2);
386 if (sport->dma_is_enabled) {
387 ucr1 |= UCR1_RXDMAEN | UCR1_ATDMAEN;
393 /* Write UCR2 first as it includes RXEN */
394 imx_uart_writel(sport, ucr2, UCR2);
395 imx_uart_writel(sport, ucr1, UCR1);
396 imx_uart_disable_loopback_rs485(sport);
399 /* called with port.lock taken and irqs off */
400 static void imx_uart_stop_tx(struct uart_port *port)
402 struct imx_port *sport = (struct imx_port *)port;
403 u32 ucr1, ucr4, usr2;
405 if (sport->tx_state == OFF)
409 * We are maybe in the SMP context, so if the DMA TX thread is running
410 * on other cpu, we have to wait for it to finish.
412 if (sport->dma_is_txing)
415 ucr1 = imx_uart_readl(sport, UCR1);
416 imx_uart_writel(sport, ucr1 & ~UCR1_TRDYEN, UCR1);
418 ucr4 = imx_uart_readl(sport, UCR4);
419 usr2 = imx_uart_readl(sport, USR2);
420 if ((!(usr2 & USR2_TXDC)) && (ucr4 & UCR4_TCEN)) {
421 /* The shifter is still busy, so retry once TC triggers */
426 imx_uart_writel(sport, ucr4, UCR4);
428 /* in rs485 mode disable transmitter */
429 if (port->rs485.flags & SER_RS485_ENABLED) {
430 if (sport->tx_state == SEND) {
431 sport->tx_state = WAIT_AFTER_SEND;
433 if (port->rs485.delay_rts_after_send > 0) {
434 start_hrtimer_ms(&sport->trigger_stop_tx,
435 port->rs485.delay_rts_after_send);
439 /* continue without any delay */
442 if (sport->tx_state == WAIT_AFTER_RTS ||
443 sport->tx_state == WAIT_AFTER_SEND) {
446 hrtimer_try_to_cancel(&sport->trigger_start_tx);
448 ucr2 = imx_uart_readl(sport, UCR2);
449 if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND)
450 imx_uart_rts_active(sport, &ucr2);
452 imx_uart_rts_inactive(sport, &ucr2);
453 imx_uart_writel(sport, ucr2, UCR2);
455 if (!port->rs485_rx_during_tx_gpio)
456 imx_uart_start_rx(port);
458 sport->tx_state = OFF;
461 sport->tx_state = OFF;
465 /* called with port.lock taken and irqs off */
466 static void imx_uart_stop_rx(struct uart_port *port)
468 struct imx_port *sport = (struct imx_port *)port;
469 u32 ucr1, ucr2, ucr4, uts;
471 ucr1 = imx_uart_readl(sport, UCR1);
472 ucr2 = imx_uart_readl(sport, UCR2);
473 ucr4 = imx_uart_readl(sport, UCR4);
475 if (sport->dma_is_enabled) {
476 ucr1 &= ~(UCR1_RXDMAEN | UCR1_ATDMAEN);
478 ucr1 &= ~UCR1_RRDYEN;
482 imx_uart_writel(sport, ucr1, UCR1);
483 imx_uart_writel(sport, ucr4, UCR4);
485 /* See SER_RS485_ENABLED/UTS_LOOP comment in imx_uart_probe() */
486 if (port->rs485.flags & SER_RS485_ENABLED &&
487 port->rs485.flags & SER_RS485_RTS_ON_SEND &&
488 sport->have_rtscts && !sport->have_rtsgpio) {
489 uts = imx_uart_readl(sport, imx_uart_uts_reg(sport));
491 imx_uart_writel(sport, uts, imx_uart_uts_reg(sport));
497 imx_uart_writel(sport, ucr2, UCR2);
500 /* called with port.lock taken and irqs off */
501 static void imx_uart_enable_ms(struct uart_port *port)
503 struct imx_port *sport = (struct imx_port *)port;
505 mod_timer(&sport->timer, jiffies);
507 mctrl_gpio_enable_ms(sport->gpios);
510 static void imx_uart_dma_tx(struct imx_port *sport);
512 /* called with port.lock taken and irqs off */
513 static inline void imx_uart_transmit_buffer(struct imx_port *sport)
515 struct circ_buf *xmit = &sport->port.state->xmit;
517 if (sport->port.x_char) {
519 imx_uart_writel(sport, sport->port.x_char, URTX0);
520 sport->port.icount.tx++;
521 sport->port.x_char = 0;
525 if (uart_circ_empty(xmit) || uart_tx_stopped(&sport->port)) {
526 imx_uart_stop_tx(&sport->port);
530 if (sport->dma_is_enabled) {
533 * We've just sent a X-char Ensure the TX DMA is enabled
534 * and the TX IRQ is disabled.
536 ucr1 = imx_uart_readl(sport, UCR1);
537 ucr1 &= ~UCR1_TRDYEN;
538 if (sport->dma_is_txing) {
539 ucr1 |= UCR1_TXDMAEN;
540 imx_uart_writel(sport, ucr1, UCR1);
542 imx_uart_writel(sport, ucr1, UCR1);
543 imx_uart_dma_tx(sport);
549 while (!uart_circ_empty(xmit) &&
550 !(imx_uart_readl(sport, imx_uart_uts_reg(sport)) & UTS_TXFULL)) {
551 /* send xmit->buf[xmit->tail]
552 * out the port here */
553 imx_uart_writel(sport, xmit->buf[xmit->tail], URTX0);
554 uart_xmit_advance(&sport->port, 1);
557 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
558 uart_write_wakeup(&sport->port);
560 if (uart_circ_empty(xmit))
561 imx_uart_stop_tx(&sport->port);
564 static void imx_uart_dma_tx_callback(void *data)
566 struct imx_port *sport = data;
567 struct scatterlist *sgl = &sport->tx_sgl[0];
568 struct circ_buf *xmit = &sport->port.state->xmit;
572 uart_port_lock_irqsave(&sport->port, &flags);
574 dma_unmap_sg(sport->port.dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE);
576 ucr1 = imx_uart_readl(sport, UCR1);
577 ucr1 &= ~UCR1_TXDMAEN;
578 imx_uart_writel(sport, ucr1, UCR1);
580 uart_xmit_advance(&sport->port, sport->tx_bytes);
582 dev_dbg(sport->port.dev, "we finish the TX DMA.\n");
584 sport->dma_is_txing = 0;
586 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
587 uart_write_wakeup(&sport->port);
589 if (!uart_circ_empty(xmit) && !uart_tx_stopped(&sport->port))
590 imx_uart_dma_tx(sport);
591 else if (sport->port.rs485.flags & SER_RS485_ENABLED) {
592 u32 ucr4 = imx_uart_readl(sport, UCR4);
594 imx_uart_writel(sport, ucr4, UCR4);
597 uart_port_unlock_irqrestore(&sport->port, flags);
600 /* called with port.lock taken and irqs off */
601 static void imx_uart_dma_tx(struct imx_port *sport)
603 struct circ_buf *xmit = &sport->port.state->xmit;
604 struct scatterlist *sgl = sport->tx_sgl;
605 struct dma_async_tx_descriptor *desc;
606 struct dma_chan *chan = sport->dma_chan_tx;
607 struct device *dev = sport->port.dev;
611 if (sport->dma_is_txing)
614 ucr4 = imx_uart_readl(sport, UCR4);
616 imx_uart_writel(sport, ucr4, UCR4);
618 sport->tx_bytes = uart_circ_chars_pending(xmit);
620 if (xmit->tail < xmit->head || xmit->head == 0) {
621 sport->dma_tx_nents = 1;
622 sg_init_one(sgl, xmit->buf + xmit->tail, sport->tx_bytes);
624 sport->dma_tx_nents = 2;
625 sg_init_table(sgl, 2);
626 sg_set_buf(sgl, xmit->buf + xmit->tail,
627 UART_XMIT_SIZE - xmit->tail);
628 sg_set_buf(sgl + 1, xmit->buf, xmit->head);
631 ret = dma_map_sg(dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE);
633 dev_err(dev, "DMA mapping error for TX.\n");
636 desc = dmaengine_prep_slave_sg(chan, sgl, ret,
637 DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT);
639 dma_unmap_sg(dev, sgl, sport->dma_tx_nents,
641 dev_err(dev, "We cannot prepare for the TX slave dma!\n");
644 desc->callback = imx_uart_dma_tx_callback;
645 desc->callback_param = sport;
647 dev_dbg(dev, "TX: prepare to send %lu bytes by DMA.\n",
648 uart_circ_chars_pending(xmit));
650 ucr1 = imx_uart_readl(sport, UCR1);
651 ucr1 |= UCR1_TXDMAEN;
652 imx_uart_writel(sport, ucr1, UCR1);
655 sport->dma_is_txing = 1;
656 dmaengine_submit(desc);
657 dma_async_issue_pending(chan);
661 /* called with port.lock taken and irqs off */
662 static void imx_uart_start_tx(struct uart_port *port)
664 struct imx_port *sport = (struct imx_port *)port;
667 if (!sport->port.x_char && uart_circ_empty(&port->state->xmit))
671 * We cannot simply do nothing here if sport->tx_state == SEND already
672 * because UCR1_TXMPTYEN might already have been cleared in
673 * imx_uart_stop_tx(), but tx_state is still SEND.
676 if (port->rs485.flags & SER_RS485_ENABLED) {
677 if (sport->tx_state == OFF) {
678 u32 ucr2 = imx_uart_readl(sport, UCR2);
679 if (port->rs485.flags & SER_RS485_RTS_ON_SEND)
680 imx_uart_rts_active(sport, &ucr2);
682 imx_uart_rts_inactive(sport, &ucr2);
683 imx_uart_writel(sport, ucr2, UCR2);
685 if (!(port->rs485.flags & SER_RS485_RX_DURING_TX) &&
686 !port->rs485_rx_during_tx_gpio)
687 imx_uart_stop_rx(port);
689 sport->tx_state = WAIT_AFTER_RTS;
691 if (port->rs485.delay_rts_before_send > 0) {
692 start_hrtimer_ms(&sport->trigger_start_tx,
693 port->rs485.delay_rts_before_send);
697 /* continue without any delay */
700 if (sport->tx_state == WAIT_AFTER_SEND
701 || sport->tx_state == WAIT_AFTER_RTS) {
703 hrtimer_try_to_cancel(&sport->trigger_stop_tx);
706 * Enable transmitter and shifter empty irq only if DMA
707 * is off. In the DMA case this is done in the
710 if (!sport->dma_is_enabled) {
711 u32 ucr4 = imx_uart_readl(sport, UCR4);
713 imx_uart_writel(sport, ucr4, UCR4);
716 sport->tx_state = SEND;
719 sport->tx_state = SEND;
722 if (!sport->dma_is_enabled) {
723 ucr1 = imx_uart_readl(sport, UCR1);
724 imx_uart_writel(sport, ucr1 | UCR1_TRDYEN, UCR1);
727 if (sport->dma_is_enabled) {
728 if (sport->port.x_char) {
729 /* We have X-char to send, so enable TX IRQ and
730 * disable TX DMA to let TX interrupt to send X-char */
731 ucr1 = imx_uart_readl(sport, UCR1);
732 ucr1 &= ~UCR1_TXDMAEN;
734 imx_uart_writel(sport, ucr1, UCR1);
738 if (!uart_circ_empty(&port->state->xmit) &&
739 !uart_tx_stopped(port))
740 imx_uart_dma_tx(sport);
745 static irqreturn_t __imx_uart_rtsint(int irq, void *dev_id)
747 struct imx_port *sport = dev_id;
750 imx_uart_writel(sport, USR1_RTSD, USR1);
751 usr1 = imx_uart_readl(sport, USR1) & USR1_RTSS;
752 uart_handle_cts_change(&sport->port, usr1);
753 wake_up_interruptible(&sport->port.state->port.delta_msr_wait);
758 static irqreturn_t imx_uart_rtsint(int irq, void *dev_id)
760 struct imx_port *sport = dev_id;
763 uart_port_lock(&sport->port);
765 ret = __imx_uart_rtsint(irq, dev_id);
767 uart_port_unlock(&sport->port);
772 static irqreturn_t imx_uart_txint(int irq, void *dev_id)
774 struct imx_port *sport = dev_id;
776 uart_port_lock(&sport->port);
777 imx_uart_transmit_buffer(sport);
778 uart_port_unlock(&sport->port);
782 /* Check if hardware Rx flood is in progress, and issue soft reset to stop it.
783 * This is to be called from Rx ISRs only when some bytes were actually
786 * A way to reproduce the flood (checked on iMX6SX) is: open iMX UART at 9600
787 * 8N1, and from external source send 0xf0 char at 115200 8N1. In about 90% of
788 * cases this starts a flood of "receiving" of 0xff characters by the iMX6 UART
789 * that is terminated by any activity on RxD line, or could be stopped by
790 * issuing soft reset to the UART (just stop/start of RX does not help). Note
791 * that what we do here is sending isolated start bit about 2.4 times shorter
792 * than it is to be on UART configured baud rate.
794 static void imx_uart_check_flood(struct imx_port *sport, u32 usr2)
796 /* To detect hardware 0xff flood we monitor RxD line between RX
797 * interrupts to isolate "receiving" of char(s) with no activity
798 * on RxD line, that'd never happen on actual data transfers.
800 * We use USR2_WAKE bit to check for activity on RxD line, but we have a
801 * race here if we clear USR2_WAKE when receiving of a char is in
802 * progress, so we might get RX interrupt later with USR2_WAKE bit
803 * cleared. Note though that as we don't try to clear USR2_WAKE when we
804 * detected no activity, this race may hide actual activity only once.
806 * Yet another case where receive interrupt may occur without RxD
807 * activity is expiration of aging timer, so we consider this as well.
809 * We use 'idle_counter' to ensure that we got at least so many RX
810 * interrupts without any detected activity on RxD line. 2 cases
811 * described plus 1 to be on the safe side gives us a margin of 3,
812 * below. In practice I was not able to produce a false positive to
813 * induce soft reset at regular data transfers even using 1 as the
814 * margin, so 3 is actually very strong.
816 * We count interrupts, not chars in 'idle-counter' for simplicity.
819 if (usr2 & USR2_WAKE) {
820 imx_uart_writel(sport, USR2_WAKE, USR2);
821 sport->idle_counter = 0;
822 } else if (++sport->idle_counter > 3) {
823 dev_warn(sport->port.dev, "RX flood detected: soft reset.");
824 imx_uart_soft_reset(sport); /* also clears 'sport->idle_counter' */
828 static irqreturn_t __imx_uart_rxint(int irq, void *dev_id)
830 struct imx_port *sport = dev_id;
831 struct tty_port *port = &sport->port.state->port;
834 /* If we received something, check for 0xff flood */
835 usr2 = imx_uart_readl(sport, USR2);
837 imx_uart_check_flood(sport, usr2);
839 while ((rx = imx_uart_readl(sport, URXD0)) & URXD_CHARRDY) {
840 unsigned int flg = TTY_NORMAL;
841 sport->port.icount.rx++;
843 if (unlikely(rx & URXD_ERR)) {
845 sport->port.icount.brk++;
846 if (uart_handle_break(&sport->port))
849 else if (rx & URXD_PRERR)
850 sport->port.icount.parity++;
851 else if (rx & URXD_FRMERR)
852 sport->port.icount.frame++;
853 if (rx & URXD_OVRRUN)
854 sport->port.icount.overrun++;
856 if (rx & sport->port.ignore_status_mask)
859 rx &= (sport->port.read_status_mask | 0xFF);
863 else if (rx & URXD_PRERR)
865 else if (rx & URXD_FRMERR)
867 if (rx & URXD_OVRRUN)
870 sport->port.sysrq = 0;
871 } else if (uart_handle_sysrq_char(&sport->port, (unsigned char)rx)) {
875 if (sport->port.ignore_status_mask & URXD_DUMMY_READ)
878 if (tty_insert_flip_char(port, rx, flg) == 0)
879 sport->port.icount.buf_overrun++;
882 tty_flip_buffer_push(port);
887 static irqreturn_t imx_uart_rxint(int irq, void *dev_id)
889 struct imx_port *sport = dev_id;
892 uart_port_lock(&sport->port);
894 ret = __imx_uart_rxint(irq, dev_id);
896 uart_port_unlock(&sport->port);
901 static void imx_uart_clear_rx_errors(struct imx_port *sport);
904 * We have a modem side uart, so the meanings of RTS and CTS are inverted.
906 static unsigned int imx_uart_get_hwmctrl(struct imx_port *sport)
908 unsigned int tmp = TIOCM_DSR;
909 unsigned usr1 = imx_uart_readl(sport, USR1);
910 unsigned usr2 = imx_uart_readl(sport, USR2);
912 if (usr1 & USR1_RTSS)
915 /* in DCE mode DCDIN is always 0 */
916 if (!(usr2 & USR2_DCDIN))
920 if (!(imx_uart_readl(sport, USR2) & USR2_RIIN))
927 * Handle any change of modem status signal since we were last called.
929 static void imx_uart_mctrl_check(struct imx_port *sport)
931 unsigned int status, changed;
933 status = imx_uart_get_hwmctrl(sport);
934 changed = status ^ sport->old_status;
939 sport->old_status = status;
941 if (changed & TIOCM_RI && status & TIOCM_RI)
942 sport->port.icount.rng++;
943 if (changed & TIOCM_DSR)
944 sport->port.icount.dsr++;
945 if (changed & TIOCM_CAR)
946 uart_handle_dcd_change(&sport->port, status & TIOCM_CAR);
947 if (changed & TIOCM_CTS)
948 uart_handle_cts_change(&sport->port, status & TIOCM_CTS);
950 wake_up_interruptible(&sport->port.state->port.delta_msr_wait);
953 static irqreturn_t imx_uart_int(int irq, void *dev_id)
955 struct imx_port *sport = dev_id;
956 unsigned int usr1, usr2, ucr1, ucr2, ucr3, ucr4;
957 irqreturn_t ret = IRQ_NONE;
959 uart_port_lock(&sport->port);
961 usr1 = imx_uart_readl(sport, USR1);
962 usr2 = imx_uart_readl(sport, USR2);
963 ucr1 = imx_uart_readl(sport, UCR1);
964 ucr2 = imx_uart_readl(sport, UCR2);
965 ucr3 = imx_uart_readl(sport, UCR3);
966 ucr4 = imx_uart_readl(sport, UCR4);
969 * Even if a condition is true that can trigger an irq only handle it if
970 * the respective irq source is enabled. This prevents some undesired
971 * actions, for example if a character that sits in the RX FIFO and that
972 * should be fetched via DMA is tried to be fetched using PIO. Or the
973 * receiver is currently off and so reading from URXD0 results in an
974 * exception. So just mask the (raw) status bits for disabled irqs.
976 if ((ucr1 & UCR1_RRDYEN) == 0)
978 if ((ucr2 & UCR2_ATEN) == 0)
980 if ((ucr1 & UCR1_TRDYEN) == 0)
982 if ((ucr4 & UCR4_TCEN) == 0)
984 if ((ucr3 & UCR3_DTRDEN) == 0)
986 if ((ucr1 & UCR1_RTSDEN) == 0)
988 if ((ucr3 & UCR3_AWAKEN) == 0)
990 if ((ucr4 & UCR4_OREN) == 0)
993 if (usr1 & (USR1_RRDY | USR1_AGTIM)) {
994 imx_uart_writel(sport, USR1_AGTIM, USR1);
996 __imx_uart_rxint(irq, dev_id);
1000 if ((usr1 & USR1_TRDY) || (usr2 & USR2_TXDC)) {
1001 imx_uart_transmit_buffer(sport);
1005 if (usr1 & USR1_DTRD) {
1006 imx_uart_writel(sport, USR1_DTRD, USR1);
1008 imx_uart_mctrl_check(sport);
1013 if (usr1 & USR1_RTSD) {
1014 __imx_uart_rtsint(irq, dev_id);
1018 if (usr1 & USR1_AWAKE) {
1019 imx_uart_writel(sport, USR1_AWAKE, USR1);
1023 if (usr2 & USR2_ORE) {
1024 sport->port.icount.overrun++;
1025 imx_uart_writel(sport, USR2_ORE, USR2);
1029 uart_port_unlock(&sport->port);
1035 * Return TIOCSER_TEMT when transmitter is not busy.
1037 static unsigned int imx_uart_tx_empty(struct uart_port *port)
1039 struct imx_port *sport = (struct imx_port *)port;
1042 ret = (imx_uart_readl(sport, USR2) & USR2_TXDC) ? TIOCSER_TEMT : 0;
1044 /* If the TX DMA is working, return 0. */
1045 if (sport->dma_is_txing)
1051 /* called with port.lock taken and irqs off */
1052 static unsigned int imx_uart_get_mctrl(struct uart_port *port)
1054 struct imx_port *sport = (struct imx_port *)port;
1055 unsigned int ret = imx_uart_get_hwmctrl(sport);
1057 mctrl_gpio_get(sport->gpios, &ret);
1062 /* called with port.lock taken and irqs off */
1063 static void imx_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
1065 struct imx_port *sport = (struct imx_port *)port;
1068 if (!(port->rs485.flags & SER_RS485_ENABLED)) {
1072 * Turn off autoRTS if RTS is lowered and restore autoRTS
1073 * setting if RTS is raised.
1075 ucr2 = imx_uart_readl(sport, UCR2);
1076 ucr2 &= ~(UCR2_CTS | UCR2_CTSC);
1077 if (mctrl & TIOCM_RTS) {
1080 * UCR2_IRTS is unset if and only if the port is
1081 * configured for CRTSCTS, so we use inverted UCR2_IRTS
1082 * to get the state to restore to.
1084 if (!(ucr2 & UCR2_IRTS))
1087 imx_uart_writel(sport, ucr2, UCR2);
1090 ucr3 = imx_uart_readl(sport, UCR3) & ~UCR3_DSR;
1091 if (!(mctrl & TIOCM_DTR))
1093 imx_uart_writel(sport, ucr3, UCR3);
1095 uts = imx_uart_readl(sport, imx_uart_uts_reg(sport)) & ~UTS_LOOP;
1096 if (mctrl & TIOCM_LOOP)
1098 imx_uart_writel(sport, uts, imx_uart_uts_reg(sport));
1100 mctrl_gpio_set(sport->gpios, mctrl);
1104 * Interrupts always disabled.
1106 static void imx_uart_break_ctl(struct uart_port *port, int break_state)
1108 struct imx_port *sport = (struct imx_port *)port;
1109 unsigned long flags;
1112 uart_port_lock_irqsave(&sport->port, &flags);
1114 ucr1 = imx_uart_readl(sport, UCR1) & ~UCR1_SNDBRK;
1116 if (break_state != 0)
1117 ucr1 |= UCR1_SNDBRK;
1119 imx_uart_writel(sport, ucr1, UCR1);
1121 uart_port_unlock_irqrestore(&sport->port, flags);
1125 * This is our per-port timeout handler, for checking the
1126 * modem status signals.
1128 static void imx_uart_timeout(struct timer_list *t)
1130 struct imx_port *sport = from_timer(sport, t, timer);
1131 unsigned long flags;
1133 if (sport->port.state) {
1134 uart_port_lock_irqsave(&sport->port, &flags);
1135 imx_uart_mctrl_check(sport);
1136 uart_port_unlock_irqrestore(&sport->port, flags);
1138 mod_timer(&sport->timer, jiffies + MCTRL_TIMEOUT);
1143 * There are two kinds of RX DMA interrupts(such as in the MX6Q):
1144 * [1] the RX DMA buffer is full.
1145 * [2] the aging timer expires
1147 * Condition [2] is triggered when a character has been sitting in the FIFO
1148 * for at least 8 byte durations.
1150 static void imx_uart_dma_rx_callback(void *data)
1152 struct imx_port *sport = data;
1153 struct dma_chan *chan = sport->dma_chan_rx;
1154 struct scatterlist *sgl = &sport->rx_sgl;
1155 struct tty_port *port = &sport->port.state->port;
1156 struct dma_tx_state state;
1157 struct circ_buf *rx_ring = &sport->rx_ring;
1158 enum dma_status status;
1159 unsigned int w_bytes = 0;
1160 unsigned int r_bytes;
1161 unsigned int bd_size;
1163 status = dmaengine_tx_status(chan, sport->rx_cookie, &state);
1165 if (status == DMA_ERROR) {
1166 uart_port_lock(&sport->port);
1167 imx_uart_clear_rx_errors(sport);
1168 uart_port_unlock(&sport->port);
1173 * The state-residue variable represents the empty space
1174 * relative to the entire buffer. Taking this in consideration
1175 * the head is always calculated base on the buffer total
1176 * length - DMA transaction residue. The UART script from the
1177 * SDMA firmware will jump to the next buffer descriptor,
1178 * once a DMA transaction if finalized (IMX53 RM - A.4.1.2.4).
1179 * Taking this in consideration the tail is always at the
1180 * beginning of the buffer descriptor that contains the head.
1183 /* Calculate the head */
1184 rx_ring->head = sg_dma_len(sgl) - state.residue;
1186 /* Calculate the tail. */
1187 bd_size = sg_dma_len(sgl) / sport->rx_periods;
1188 rx_ring->tail = ((rx_ring->head-1) / bd_size) * bd_size;
1190 if (rx_ring->head <= sg_dma_len(sgl) &&
1191 rx_ring->head > rx_ring->tail) {
1193 /* Move data from tail to head */
1194 r_bytes = rx_ring->head - rx_ring->tail;
1196 /* If we received something, check for 0xff flood */
1197 uart_port_lock(&sport->port);
1198 imx_uart_check_flood(sport, imx_uart_readl(sport, USR2));
1199 uart_port_unlock(&sport->port);
1201 if (!(sport->port.ignore_status_mask & URXD_DUMMY_READ)) {
1203 /* CPU claims ownership of RX DMA buffer */
1204 dma_sync_sg_for_cpu(sport->port.dev, sgl, 1,
1207 w_bytes = tty_insert_flip_string(port,
1208 sport->rx_buf + rx_ring->tail, r_bytes);
1210 /* UART retrieves ownership of RX DMA buffer */
1211 dma_sync_sg_for_device(sport->port.dev, sgl, 1,
1214 if (w_bytes != r_bytes)
1215 sport->port.icount.buf_overrun++;
1217 sport->port.icount.rx += w_bytes;
1220 WARN_ON(rx_ring->head > sg_dma_len(sgl));
1221 WARN_ON(rx_ring->head <= rx_ring->tail);
1225 tty_flip_buffer_push(port);
1226 dev_dbg(sport->port.dev, "We get %d bytes.\n", w_bytes);
1230 static int imx_uart_start_rx_dma(struct imx_port *sport)
1232 struct scatterlist *sgl = &sport->rx_sgl;
1233 struct dma_chan *chan = sport->dma_chan_rx;
1234 struct device *dev = sport->port.dev;
1235 struct dma_async_tx_descriptor *desc;
1238 sport->rx_ring.head = 0;
1239 sport->rx_ring.tail = 0;
1241 sg_init_one(sgl, sport->rx_buf, sport->rx_buf_size);
1242 ret = dma_map_sg(dev, sgl, 1, DMA_FROM_DEVICE);
1244 dev_err(dev, "DMA mapping error for RX.\n");
1248 desc = dmaengine_prep_dma_cyclic(chan, sg_dma_address(sgl),
1249 sg_dma_len(sgl), sg_dma_len(sgl) / sport->rx_periods,
1250 DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT);
1253 dma_unmap_sg(dev, sgl, 1, DMA_FROM_DEVICE);
1254 dev_err(dev, "We cannot prepare for the RX slave dma!\n");
1257 desc->callback = imx_uart_dma_rx_callback;
1258 desc->callback_param = sport;
1260 dev_dbg(dev, "RX: prepare for the DMA.\n");
1261 sport->dma_is_rxing = 1;
1262 sport->rx_cookie = dmaengine_submit(desc);
1263 dma_async_issue_pending(chan);
1267 static void imx_uart_clear_rx_errors(struct imx_port *sport)
1269 struct tty_port *port = &sport->port.state->port;
1272 usr1 = imx_uart_readl(sport, USR1);
1273 usr2 = imx_uart_readl(sport, USR2);
1275 if (usr2 & USR2_BRCD) {
1276 sport->port.icount.brk++;
1277 imx_uart_writel(sport, USR2_BRCD, USR2);
1278 uart_handle_break(&sport->port);
1279 if (tty_insert_flip_char(port, 0, TTY_BREAK) == 0)
1280 sport->port.icount.buf_overrun++;
1281 tty_flip_buffer_push(port);
1283 if (usr1 & USR1_FRAMERR) {
1284 sport->port.icount.frame++;
1285 imx_uart_writel(sport, USR1_FRAMERR, USR1);
1286 } else if (usr1 & USR1_PARITYERR) {
1287 sport->port.icount.parity++;
1288 imx_uart_writel(sport, USR1_PARITYERR, USR1);
1292 if (usr2 & USR2_ORE) {
1293 sport->port.icount.overrun++;
1294 imx_uart_writel(sport, USR2_ORE, USR2);
1297 sport->idle_counter = 0;
1301 #define TXTL_DEFAULT 2 /* reset default */
1302 #define RXTL_DEFAULT 8 /* 8 characters or aging timer */
1303 #define TXTL_DMA 8 /* DMA burst setting */
1304 #define RXTL_DMA 9 /* DMA burst setting */
1306 static void imx_uart_setup_ufcr(struct imx_port *sport,
1307 unsigned char txwl, unsigned char rxwl)
1311 /* set receiver / transmitter trigger level */
1312 val = imx_uart_readl(sport, UFCR) & (UFCR_RFDIV | UFCR_DCEDTE);
1313 val |= txwl << UFCR_TXTL_SHF | rxwl;
1314 imx_uart_writel(sport, val, UFCR);
1317 static void imx_uart_dma_exit(struct imx_port *sport)
1319 if (sport->dma_chan_rx) {
1320 dmaengine_terminate_sync(sport->dma_chan_rx);
1321 dma_release_channel(sport->dma_chan_rx);
1322 sport->dma_chan_rx = NULL;
1323 sport->rx_cookie = -EINVAL;
1324 kfree(sport->rx_buf);
1325 sport->rx_buf = NULL;
1328 if (sport->dma_chan_tx) {
1329 dmaengine_terminate_sync(sport->dma_chan_tx);
1330 dma_release_channel(sport->dma_chan_tx);
1331 sport->dma_chan_tx = NULL;
1335 static int imx_uart_dma_init(struct imx_port *sport)
1337 struct dma_slave_config slave_config = {};
1338 struct device *dev = sport->port.dev;
1339 struct dma_chan *chan;
1342 /* Prepare for RX : */
1343 chan = dma_request_chan(dev, "rx");
1345 dev_dbg(dev, "cannot get the DMA channel.\n");
1346 sport->dma_chan_rx = NULL;
1347 ret = PTR_ERR(chan);
1350 sport->dma_chan_rx = chan;
1352 slave_config.direction = DMA_DEV_TO_MEM;
1353 slave_config.src_addr = sport->port.mapbase + URXD0;
1354 slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1355 /* one byte less than the watermark level to enable the aging timer */
1356 slave_config.src_maxburst = RXTL_DMA - 1;
1357 ret = dmaengine_slave_config(sport->dma_chan_rx, &slave_config);
1359 dev_err(dev, "error in RX dma configuration.\n");
1363 sport->rx_buf_size = sport->rx_period_length * sport->rx_periods;
1364 sport->rx_buf = kzalloc(sport->rx_buf_size, GFP_KERNEL);
1365 if (!sport->rx_buf) {
1369 sport->rx_ring.buf = sport->rx_buf;
1371 /* Prepare for TX : */
1372 chan = dma_request_chan(dev, "tx");
1374 dev_err(dev, "cannot get the TX DMA channel!\n");
1375 sport->dma_chan_tx = NULL;
1376 ret = PTR_ERR(chan);
1379 sport->dma_chan_tx = chan;
1381 slave_config.direction = DMA_MEM_TO_DEV;
1382 slave_config.dst_addr = sport->port.mapbase + URTX0;
1383 slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1384 slave_config.dst_maxburst = TXTL_DMA;
1385 ret = dmaengine_slave_config(sport->dma_chan_tx, &slave_config);
1387 dev_err(dev, "error in TX dma configuration.");
1393 imx_uart_dma_exit(sport);
1397 static void imx_uart_enable_dma(struct imx_port *sport)
1401 imx_uart_setup_ufcr(sport, TXTL_DMA, RXTL_DMA);
1404 ucr1 = imx_uart_readl(sport, UCR1);
1405 ucr1 |= UCR1_RXDMAEN | UCR1_TXDMAEN | UCR1_ATDMAEN;
1406 imx_uart_writel(sport, ucr1, UCR1);
1408 sport->dma_is_enabled = 1;
1411 static void imx_uart_disable_dma(struct imx_port *sport)
1416 ucr1 = imx_uart_readl(sport, UCR1);
1417 ucr1 &= ~(UCR1_RXDMAEN | UCR1_TXDMAEN | UCR1_ATDMAEN);
1418 imx_uart_writel(sport, ucr1, UCR1);
1420 imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT);
1422 sport->dma_is_enabled = 0;
1425 /* half the RX buffer size */
1428 static int imx_uart_startup(struct uart_port *port)
1430 struct imx_port *sport = (struct imx_port *)port;
1432 unsigned long flags;
1433 int dma_is_inited = 0;
1434 u32 ucr1, ucr2, ucr3, ucr4;
1436 retval = clk_prepare_enable(sport->clk_per);
1439 retval = clk_prepare_enable(sport->clk_ipg);
1441 clk_disable_unprepare(sport->clk_per);
1445 imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT);
1447 /* disable the DREN bit (Data Ready interrupt enable) before
1450 ucr4 = imx_uart_readl(sport, UCR4);
1452 /* set the trigger level for CTS */
1453 ucr4 &= ~(UCR4_CTSTL_MASK << UCR4_CTSTL_SHF);
1454 ucr4 |= CTSTL << UCR4_CTSTL_SHF;
1456 imx_uart_writel(sport, ucr4 & ~UCR4_DREN, UCR4);
1458 /* Can we enable the DMA support? */
1459 if (!uart_console(port) && imx_uart_dma_init(sport) == 0) {
1460 lockdep_set_subclass(&port->lock, 1);
1464 uart_port_lock_irqsave(&sport->port, &flags);
1466 /* Reset fifo's and state machines */
1467 imx_uart_soft_reset(sport);
1470 * Finally, clear and enable interrupts
1472 imx_uart_writel(sport, USR1_RTSD | USR1_DTRD, USR1);
1473 imx_uart_writel(sport, USR2_ORE, USR2);
1475 ucr1 = imx_uart_readl(sport, UCR1) & ~UCR1_RRDYEN;
1476 ucr1 |= UCR1_UARTEN;
1477 if (sport->have_rtscts)
1478 ucr1 |= UCR1_RTSDEN;
1480 imx_uart_writel(sport, ucr1, UCR1);
1482 ucr4 = imx_uart_readl(sport, UCR4) & ~(UCR4_OREN | UCR4_INVR);
1485 if (sport->inverted_rx)
1487 imx_uart_writel(sport, ucr4, UCR4);
1489 ucr3 = imx_uart_readl(sport, UCR3) & ~UCR3_INVT;
1491 * configure tx polarity before enabling tx
1493 if (sport->inverted_tx)
1496 if (!imx_uart_is_imx1(sport)) {
1497 ucr3 |= UCR3_DTRDEN | UCR3_RI | UCR3_DCD;
1499 if (sport->dte_mode)
1500 /* disable broken interrupts */
1501 ucr3 &= ~(UCR3_RI | UCR3_DCD);
1503 imx_uart_writel(sport, ucr3, UCR3);
1505 ucr2 = imx_uart_readl(sport, UCR2) & ~UCR2_ATEN;
1506 ucr2 |= (UCR2_RXEN | UCR2_TXEN);
1507 if (!sport->have_rtscts)
1510 * make sure the edge sensitive RTS-irq is disabled,
1511 * we're using RTSD instead.
1513 if (!imx_uart_is_imx1(sport))
1514 ucr2 &= ~UCR2_RTSEN;
1515 imx_uart_writel(sport, ucr2, UCR2);
1518 * Enable modem status interrupts
1520 imx_uart_enable_ms(&sport->port);
1522 if (dma_is_inited) {
1523 imx_uart_enable_dma(sport);
1524 imx_uart_start_rx_dma(sport);
1526 ucr1 = imx_uart_readl(sport, UCR1);
1527 ucr1 |= UCR1_RRDYEN;
1528 imx_uart_writel(sport, ucr1, UCR1);
1530 ucr2 = imx_uart_readl(sport, UCR2);
1532 imx_uart_writel(sport, ucr2, UCR2);
1535 imx_uart_disable_loopback_rs485(sport);
1537 uart_port_unlock_irqrestore(&sport->port, flags);
1542 static void imx_uart_shutdown(struct uart_port *port)
1544 struct imx_port *sport = (struct imx_port *)port;
1545 unsigned long flags;
1546 u32 ucr1, ucr2, ucr4, uts;
1548 if (sport->dma_is_enabled) {
1549 dmaengine_terminate_sync(sport->dma_chan_tx);
1550 if (sport->dma_is_txing) {
1551 dma_unmap_sg(sport->port.dev, &sport->tx_sgl[0],
1552 sport->dma_tx_nents, DMA_TO_DEVICE);
1553 sport->dma_is_txing = 0;
1555 dmaengine_terminate_sync(sport->dma_chan_rx);
1556 if (sport->dma_is_rxing) {
1557 dma_unmap_sg(sport->port.dev, &sport->rx_sgl,
1558 1, DMA_FROM_DEVICE);
1559 sport->dma_is_rxing = 0;
1562 uart_port_lock_irqsave(&sport->port, &flags);
1563 imx_uart_stop_tx(port);
1564 imx_uart_stop_rx(port);
1565 imx_uart_disable_dma(sport);
1566 uart_port_unlock_irqrestore(&sport->port, flags);
1567 imx_uart_dma_exit(sport);
1570 mctrl_gpio_disable_ms(sport->gpios);
1572 uart_port_lock_irqsave(&sport->port, &flags);
1573 ucr2 = imx_uart_readl(sport, UCR2);
1574 ucr2 &= ~(UCR2_TXEN | UCR2_ATEN);
1575 imx_uart_writel(sport, ucr2, UCR2);
1576 uart_port_unlock_irqrestore(&sport->port, flags);
1581 del_timer_sync(&sport->timer);
1584 * Disable all interrupts, port and break condition.
1587 uart_port_lock_irqsave(&sport->port, &flags);
1589 ucr1 = imx_uart_readl(sport, UCR1);
1590 ucr1 &= ~(UCR1_TRDYEN | UCR1_RRDYEN | UCR1_RTSDEN | UCR1_RXDMAEN |
1591 UCR1_ATDMAEN | UCR1_SNDBRK);
1592 /* See SER_RS485_ENABLED/UTS_LOOP comment in imx_uart_probe() */
1593 if (port->rs485.flags & SER_RS485_ENABLED &&
1594 port->rs485.flags & SER_RS485_RTS_ON_SEND &&
1595 sport->have_rtscts && !sport->have_rtsgpio) {
1596 uts = imx_uart_readl(sport, imx_uart_uts_reg(sport));
1598 imx_uart_writel(sport, uts, imx_uart_uts_reg(sport));
1599 ucr1 |= UCR1_UARTEN;
1601 ucr1 &= ~UCR1_UARTEN;
1603 imx_uart_writel(sport, ucr1, UCR1);
1605 ucr4 = imx_uart_readl(sport, UCR4);
1607 imx_uart_writel(sport, ucr4, UCR4);
1609 uart_port_unlock_irqrestore(&sport->port, flags);
1611 clk_disable_unprepare(sport->clk_per);
1612 clk_disable_unprepare(sport->clk_ipg);
1615 /* called with port.lock taken and irqs off */
1616 static void imx_uart_flush_buffer(struct uart_port *port)
1618 struct imx_port *sport = (struct imx_port *)port;
1619 struct scatterlist *sgl = &sport->tx_sgl[0];
1621 if (!sport->dma_chan_tx)
1624 sport->tx_bytes = 0;
1625 dmaengine_terminate_all(sport->dma_chan_tx);
1626 if (sport->dma_is_txing) {
1629 dma_unmap_sg(sport->port.dev, sgl, sport->dma_tx_nents,
1631 ucr1 = imx_uart_readl(sport, UCR1);
1632 ucr1 &= ~UCR1_TXDMAEN;
1633 imx_uart_writel(sport, ucr1, UCR1);
1634 sport->dma_is_txing = 0;
1637 imx_uart_soft_reset(sport);
1642 imx_uart_set_termios(struct uart_port *port, struct ktermios *termios,
1643 const struct ktermios *old)
1645 struct imx_port *sport = (struct imx_port *)port;
1646 unsigned long flags;
1647 u32 ucr2, old_ucr2, ufcr;
1648 unsigned int baud, quot;
1649 unsigned int old_csize = old ? old->c_cflag & CSIZE : CS8;
1651 unsigned long num, denom, old_ubir, old_ubmr;
1655 * We only support CS7 and CS8.
1657 while ((termios->c_cflag & CSIZE) != CS7 &&
1658 (termios->c_cflag & CSIZE) != CS8) {
1659 termios->c_cflag &= ~CSIZE;
1660 termios->c_cflag |= old_csize;
1664 del_timer_sync(&sport->timer);
1667 * Ask the core to calculate the divisor for us.
1669 baud = uart_get_baud_rate(port, termios, old, 50, port->uartclk / 16);
1670 quot = uart_get_divisor(port, baud);
1672 uart_port_lock_irqsave(&sport->port, &flags);
1675 * Read current UCR2 and save it for future use, then clear all the bits
1676 * except those we will or may need to preserve.
1678 old_ucr2 = imx_uart_readl(sport, UCR2);
1679 ucr2 = old_ucr2 & (UCR2_TXEN | UCR2_RXEN | UCR2_ATEN | UCR2_CTS);
1681 ucr2 |= UCR2_SRST | UCR2_IRTS;
1682 if ((termios->c_cflag & CSIZE) == CS8)
1685 if (!sport->have_rtscts)
1686 termios->c_cflag &= ~CRTSCTS;
1688 if (port->rs485.flags & SER_RS485_ENABLED) {
1690 * RTS is mandatory for rs485 operation, so keep
1691 * it under manual control and keep transmitter
1694 if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND)
1695 imx_uart_rts_active(sport, &ucr2);
1697 imx_uart_rts_inactive(sport, &ucr2);
1699 } else if (termios->c_cflag & CRTSCTS) {
1701 * Only let receiver control RTS output if we were not requested
1702 * to have RTS inactive (which then should take precedence).
1704 if (ucr2 & UCR2_CTS)
1708 if (termios->c_cflag & CRTSCTS)
1710 if (termios->c_cflag & CSTOPB)
1712 if (termios->c_cflag & PARENB) {
1714 if (termios->c_cflag & PARODD)
1718 sport->port.read_status_mask = 0;
1719 if (termios->c_iflag & INPCK)
1720 sport->port.read_status_mask |= (URXD_FRMERR | URXD_PRERR);
1721 if (termios->c_iflag & (BRKINT | PARMRK))
1722 sport->port.read_status_mask |= URXD_BRK;
1725 * Characters to ignore
1727 sport->port.ignore_status_mask = 0;
1728 if (termios->c_iflag & IGNPAR)
1729 sport->port.ignore_status_mask |= URXD_PRERR | URXD_FRMERR;
1730 if (termios->c_iflag & IGNBRK) {
1731 sport->port.ignore_status_mask |= URXD_BRK;
1733 * If we're ignoring parity and break indicators,
1734 * ignore overruns too (for real raw support).
1736 if (termios->c_iflag & IGNPAR)
1737 sport->port.ignore_status_mask |= URXD_OVRRUN;
1740 if ((termios->c_cflag & CREAD) == 0)
1741 sport->port.ignore_status_mask |= URXD_DUMMY_READ;
1744 * Update the per-port timeout.
1746 uart_update_timeout(port, termios->c_cflag, baud);
1748 /* custom-baudrate handling */
1749 div = sport->port.uartclk / (baud * 16);
1750 if (baud == 38400 && quot != div)
1751 baud = sport->port.uartclk / (quot * 16);
1753 div = sport->port.uartclk / (baud * 16);
1759 rational_best_approximation(16 * div * baud, sport->port.uartclk,
1760 1 << 16, 1 << 16, &num, &denom);
1762 tdiv64 = sport->port.uartclk;
1764 do_div(tdiv64, denom * 16 * div);
1765 tty_termios_encode_baud_rate(termios,
1766 (speed_t)tdiv64, (speed_t)tdiv64);
1771 ufcr = imx_uart_readl(sport, UFCR);
1772 ufcr = (ufcr & (~UFCR_RFDIV)) | UFCR_RFDIV_REG(div);
1773 imx_uart_writel(sport, ufcr, UFCR);
1776 * Two registers below should always be written both and in this
1777 * particular order. One consequence is that we need to check if any of
1778 * them changes and then update both. We do need the check for change
1779 * as even writing the same values seem to "restart"
1780 * transmission/receiving logic in the hardware, that leads to data
1781 * breakage even when rate doesn't in fact change. E.g., user switches
1782 * RTS/CTS handshake and suddenly gets broken bytes.
1784 old_ubir = imx_uart_readl(sport, UBIR);
1785 old_ubmr = imx_uart_readl(sport, UBMR);
1786 if (old_ubir != num || old_ubmr != denom) {
1787 imx_uart_writel(sport, num, UBIR);
1788 imx_uart_writel(sport, denom, UBMR);
1791 if (!imx_uart_is_imx1(sport))
1792 imx_uart_writel(sport, sport->port.uartclk / div / 1000,
1795 imx_uart_writel(sport, ucr2, UCR2);
1797 if (UART_ENABLE_MS(&sport->port, termios->c_cflag))
1798 imx_uart_enable_ms(&sport->port);
1800 uart_port_unlock_irqrestore(&sport->port, flags);
1803 static const char *imx_uart_type(struct uart_port *port)
1805 return port->type == PORT_IMX ? "IMX" : NULL;
1809 * Configure/autoconfigure the port.
1811 static void imx_uart_config_port(struct uart_port *port, int flags)
1813 if (flags & UART_CONFIG_TYPE)
1814 port->type = PORT_IMX;
1818 * Verify the new serial_struct (for TIOCSSERIAL).
1819 * The only change we allow are to the flags and type, and
1820 * even then only between PORT_IMX and PORT_UNKNOWN
1823 imx_uart_verify_port(struct uart_port *port, struct serial_struct *ser)
1827 if (ser->type != PORT_UNKNOWN && ser->type != PORT_IMX)
1829 if (port->irq != ser->irq)
1831 if (ser->io_type != UPIO_MEM)
1833 if (port->uartclk / 16 != ser->baud_base)
1835 if (port->mapbase != (unsigned long)ser->iomem_base)
1837 if (port->iobase != ser->port)
1844 #if defined(CONFIG_CONSOLE_POLL)
1846 static int imx_uart_poll_init(struct uart_port *port)
1848 struct imx_port *sport = (struct imx_port *)port;
1849 unsigned long flags;
1853 retval = clk_prepare_enable(sport->clk_ipg);
1856 retval = clk_prepare_enable(sport->clk_per);
1858 clk_disable_unprepare(sport->clk_ipg);
1860 imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT);
1862 uart_port_lock_irqsave(&sport->port, &flags);
1865 * Be careful about the order of enabling bits here. First enable the
1866 * receiver (UARTEN + RXEN) and only then the corresponding irqs.
1867 * This prevents that a character that already sits in the RX fifo is
1868 * triggering an irq but the try to fetch it from there results in an
1869 * exception because UARTEN or RXEN is still off.
1871 ucr1 = imx_uart_readl(sport, UCR1);
1872 ucr2 = imx_uart_readl(sport, UCR2);
1874 if (imx_uart_is_imx1(sport))
1875 ucr1 |= IMX1_UCR1_UARTCLKEN;
1877 ucr1 |= UCR1_UARTEN;
1878 ucr1 &= ~(UCR1_TRDYEN | UCR1_RTSDEN | UCR1_RRDYEN);
1880 ucr2 |= UCR2_RXEN | UCR2_TXEN;
1883 imx_uart_writel(sport, ucr1, UCR1);
1884 imx_uart_writel(sport, ucr2, UCR2);
1886 /* now enable irqs */
1887 imx_uart_writel(sport, ucr1 | UCR1_RRDYEN, UCR1);
1888 imx_uart_writel(sport, ucr2 | UCR2_ATEN, UCR2);
1890 uart_port_unlock_irqrestore(&sport->port, flags);
1895 static int imx_uart_poll_get_char(struct uart_port *port)
1897 struct imx_port *sport = (struct imx_port *)port;
1898 if (!(imx_uart_readl(sport, USR2) & USR2_RDR))
1899 return NO_POLL_CHAR;
1901 return imx_uart_readl(sport, URXD0) & URXD_RX_DATA;
1904 static void imx_uart_poll_put_char(struct uart_port *port, unsigned char c)
1906 struct imx_port *sport = (struct imx_port *)port;
1907 unsigned int status;
1911 status = imx_uart_readl(sport, USR1);
1912 } while (~status & USR1_TRDY);
1915 imx_uart_writel(sport, c, URTX0);
1919 status = imx_uart_readl(sport, USR2);
1920 } while (~status & USR2_TXDC);
1924 /* called with port.lock taken and irqs off or from .probe without locking */
1925 static int imx_uart_rs485_config(struct uart_port *port, struct ktermios *termios,
1926 struct serial_rs485 *rs485conf)
1928 struct imx_port *sport = (struct imx_port *)port;
1931 if (rs485conf->flags & SER_RS485_ENABLED) {
1932 /* Enable receiver if low-active RTS signal is requested */
1933 if (sport->have_rtscts && !sport->have_rtsgpio &&
1934 !(rs485conf->flags & SER_RS485_RTS_ON_SEND))
1935 rs485conf->flags |= SER_RS485_RX_DURING_TX;
1937 /* disable transmitter */
1938 ucr2 = imx_uart_readl(sport, UCR2);
1939 if (rs485conf->flags & SER_RS485_RTS_AFTER_SEND)
1940 imx_uart_rts_active(sport, &ucr2);
1942 imx_uart_rts_inactive(sport, &ucr2);
1943 imx_uart_writel(sport, ucr2, UCR2);
1946 /* Make sure Rx is enabled in case Tx is active with Rx disabled */
1947 if (!(rs485conf->flags & SER_RS485_ENABLED) ||
1948 rs485conf->flags & SER_RS485_RX_DURING_TX)
1949 imx_uart_start_rx(port);
1954 static const struct uart_ops imx_uart_pops = {
1955 .tx_empty = imx_uart_tx_empty,
1956 .set_mctrl = imx_uart_set_mctrl,
1957 .get_mctrl = imx_uart_get_mctrl,
1958 .stop_tx = imx_uart_stop_tx,
1959 .start_tx = imx_uart_start_tx,
1960 .stop_rx = imx_uart_stop_rx,
1961 .enable_ms = imx_uart_enable_ms,
1962 .break_ctl = imx_uart_break_ctl,
1963 .startup = imx_uart_startup,
1964 .shutdown = imx_uart_shutdown,
1965 .flush_buffer = imx_uart_flush_buffer,
1966 .set_termios = imx_uart_set_termios,
1967 .type = imx_uart_type,
1968 .config_port = imx_uart_config_port,
1969 .verify_port = imx_uart_verify_port,
1970 #if defined(CONFIG_CONSOLE_POLL)
1971 .poll_init = imx_uart_poll_init,
1972 .poll_get_char = imx_uart_poll_get_char,
1973 .poll_put_char = imx_uart_poll_put_char,
1977 static struct imx_port *imx_uart_ports[UART_NR];
1979 #if IS_ENABLED(CONFIG_SERIAL_IMX_CONSOLE)
1980 static void imx_uart_console_putchar(struct uart_port *port, unsigned char ch)
1982 struct imx_port *sport = (struct imx_port *)port;
1984 while (imx_uart_readl(sport, imx_uart_uts_reg(sport)) & UTS_TXFULL)
1987 imx_uart_writel(sport, ch, URTX0);
1991 * Interrupts are disabled on entering
1994 imx_uart_console_write(struct console *co, const char *s, unsigned int count)
1996 struct imx_port *sport = imx_uart_ports[co->index];
1997 struct imx_port_ucrs old_ucr;
1998 unsigned long flags;
2002 if (sport->port.sysrq)
2004 else if (oops_in_progress)
2005 locked = uart_port_trylock_irqsave(&sport->port, &flags);
2007 uart_port_lock_irqsave(&sport->port, &flags);
2010 * First, save UCR1/2/3 and then disable interrupts
2012 imx_uart_ucrs_save(sport, &old_ucr);
2013 ucr1 = old_ucr.ucr1;
2015 if (imx_uart_is_imx1(sport))
2016 ucr1 |= IMX1_UCR1_UARTCLKEN;
2017 ucr1 |= UCR1_UARTEN;
2018 ucr1 &= ~(UCR1_TRDYEN | UCR1_RRDYEN | UCR1_RTSDEN);
2020 imx_uart_writel(sport, ucr1, UCR1);
2022 imx_uart_writel(sport, old_ucr.ucr2 | UCR2_TXEN, UCR2);
2024 uart_console_write(&sport->port, s, count, imx_uart_console_putchar);
2027 * Finally, wait for transmitter to become empty
2028 * and restore UCR1/2/3
2030 while (!(imx_uart_readl(sport, USR2) & USR2_TXDC));
2032 imx_uart_ucrs_restore(sport, &old_ucr);
2035 uart_port_unlock_irqrestore(&sport->port, flags);
2039 * If the port was already initialised (eg, by a boot loader),
2040 * try to determine the current setup.
2043 imx_uart_console_get_options(struct imx_port *sport, int *baud,
2044 int *parity, int *bits)
2047 if (imx_uart_readl(sport, UCR1) & UCR1_UARTEN) {
2048 /* ok, the port was enabled */
2049 unsigned int ucr2, ubir, ubmr, uartclk;
2050 unsigned int baud_raw;
2051 unsigned int ucfr_rfdiv;
2053 ucr2 = imx_uart_readl(sport, UCR2);
2056 if (ucr2 & UCR2_PREN) {
2057 if (ucr2 & UCR2_PROE)
2068 ubir = imx_uart_readl(sport, UBIR) & 0xffff;
2069 ubmr = imx_uart_readl(sport, UBMR) & 0xffff;
2071 ucfr_rfdiv = (imx_uart_readl(sport, UFCR) & UFCR_RFDIV) >> 7;
2072 if (ucfr_rfdiv == 6)
2075 ucfr_rfdiv = 6 - ucfr_rfdiv;
2077 uartclk = clk_get_rate(sport->clk_per);
2078 uartclk /= ucfr_rfdiv;
2081 * The next code provides exact computation of
2082 * baud_raw = round(((uartclk/16) * (ubir + 1)) / (ubmr + 1))
2083 * without need of float support or long long division,
2084 * which would be required to prevent 32bit arithmetic overflow
2086 unsigned int mul = ubir + 1;
2087 unsigned int div = 16 * (ubmr + 1);
2088 unsigned int rem = uartclk % div;
2090 baud_raw = (uartclk / div) * mul;
2091 baud_raw += (rem * mul + div / 2) / div;
2092 *baud = (baud_raw + 50) / 100 * 100;
2095 if (*baud != baud_raw)
2096 dev_info(sport->port.dev, "Console IMX rounded baud rate from %d to %d\n",
2102 imx_uart_console_setup(struct console *co, char *options)
2104 struct imx_port *sport;
2112 * Check whether an invalid uart number has been specified, and
2113 * if so, search for the first available port that does have
2116 if (co->index == -1 || co->index >= ARRAY_SIZE(imx_uart_ports))
2118 sport = imx_uart_ports[co->index];
2122 /* For setting the registers, we only need to enable the ipg clock. */
2123 retval = clk_prepare_enable(sport->clk_ipg);
2128 uart_parse_options(options, &baud, &parity, &bits, &flow);
2130 imx_uart_console_get_options(sport, &baud, &parity, &bits);
2132 imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT);
2134 retval = uart_set_options(&sport->port, co, baud, parity, bits, flow);
2137 clk_disable_unprepare(sport->clk_ipg);
2141 retval = clk_prepare_enable(sport->clk_per);
2143 clk_disable_unprepare(sport->clk_ipg);
2150 imx_uart_console_exit(struct console *co)
2152 struct imx_port *sport = imx_uart_ports[co->index];
2154 clk_disable_unprepare(sport->clk_per);
2155 clk_disable_unprepare(sport->clk_ipg);
2160 static struct uart_driver imx_uart_uart_driver;
2161 static struct console imx_uart_console = {
2163 .write = imx_uart_console_write,
2164 .device = uart_console_device,
2165 .setup = imx_uart_console_setup,
2166 .exit = imx_uart_console_exit,
2167 .flags = CON_PRINTBUFFER,
2169 .data = &imx_uart_uart_driver,
2172 #define IMX_CONSOLE &imx_uart_console
2175 #define IMX_CONSOLE NULL
2178 static struct uart_driver imx_uart_uart_driver = {
2179 .owner = THIS_MODULE,
2180 .driver_name = DRIVER_NAME,
2181 .dev_name = DEV_NAME,
2182 .major = SERIAL_IMX_MAJOR,
2183 .minor = MINOR_START,
2184 .nr = ARRAY_SIZE(imx_uart_ports),
2185 .cons = IMX_CONSOLE,
2188 static enum hrtimer_restart imx_trigger_start_tx(struct hrtimer *t)
2190 struct imx_port *sport = container_of(t, struct imx_port, trigger_start_tx);
2191 unsigned long flags;
2193 uart_port_lock_irqsave(&sport->port, &flags);
2194 if (sport->tx_state == WAIT_AFTER_RTS)
2195 imx_uart_start_tx(&sport->port);
2196 uart_port_unlock_irqrestore(&sport->port, flags);
2198 return HRTIMER_NORESTART;
2201 static enum hrtimer_restart imx_trigger_stop_tx(struct hrtimer *t)
2203 struct imx_port *sport = container_of(t, struct imx_port, trigger_stop_tx);
2204 unsigned long flags;
2206 uart_port_lock_irqsave(&sport->port, &flags);
2207 if (sport->tx_state == WAIT_AFTER_SEND)
2208 imx_uart_stop_tx(&sport->port);
2209 uart_port_unlock_irqrestore(&sport->port, flags);
2211 return HRTIMER_NORESTART;
2214 static const struct serial_rs485 imx_rs485_supported = {
2215 .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND |
2216 SER_RS485_RX_DURING_TX,
2217 .delay_rts_before_send = 1,
2218 .delay_rts_after_send = 1,
2221 /* Default RX DMA buffer configuration */
2222 #define RX_DMA_PERIODS 16
2223 #define RX_DMA_PERIOD_LEN (PAGE_SIZE / 4)
2225 static int imx_uart_probe(struct platform_device *pdev)
2227 struct device_node *np = pdev->dev.of_node;
2228 struct imx_port *sport;
2230 u32 dma_buf_conf[2];
2232 u32 ucr1, ucr2, uts;
2233 struct resource *res;
2234 int txirq, rxirq, rtsirq;
2236 sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL);
2240 sport->devdata = of_device_get_match_data(&pdev->dev);
2242 ret = of_alias_get_id(np, "serial");
2244 dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
2247 sport->port.line = ret;
2249 sport->have_rtscts = of_property_read_bool(np, "uart-has-rtscts") ||
2250 of_property_read_bool(np, "fsl,uart-has-rtscts"); /* deprecated */
2252 sport->dte_mode = of_property_read_bool(np, "fsl,dte-mode");
2254 sport->have_rtsgpio = of_property_present(np, "rts-gpios");
2256 sport->inverted_tx = of_property_read_bool(np, "fsl,inverted-tx");
2258 sport->inverted_rx = of_property_read_bool(np, "fsl,inverted-rx");
2260 if (!of_property_read_u32_array(np, "fsl,dma-info", dma_buf_conf, 2)) {
2261 sport->rx_period_length = dma_buf_conf[0];
2262 sport->rx_periods = dma_buf_conf[1];
2264 sport->rx_period_length = RX_DMA_PERIOD_LEN;
2265 sport->rx_periods = RX_DMA_PERIODS;
2268 if (sport->port.line >= ARRAY_SIZE(imx_uart_ports)) {
2269 dev_err(&pdev->dev, "serial%d out of range\n",
2274 base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
2276 return PTR_ERR(base);
2278 rxirq = platform_get_irq(pdev, 0);
2281 txirq = platform_get_irq_optional(pdev, 1);
2282 rtsirq = platform_get_irq_optional(pdev, 2);
2284 sport->port.dev = &pdev->dev;
2285 sport->port.mapbase = res->start;
2286 sport->port.membase = base;
2287 sport->port.type = PORT_IMX;
2288 sport->port.iotype = UPIO_MEM;
2289 sport->port.irq = rxirq;
2290 sport->port.fifosize = 32;
2291 sport->port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_IMX_CONSOLE);
2292 sport->port.ops = &imx_uart_pops;
2293 sport->port.rs485_config = imx_uart_rs485_config;
2294 /* RTS is required to control the RS485 transmitter */
2295 if (sport->have_rtscts || sport->have_rtsgpio)
2296 sport->port.rs485_supported = imx_rs485_supported;
2297 sport->port.flags = UPF_BOOT_AUTOCONF;
2298 timer_setup(&sport->timer, imx_uart_timeout, 0);
2300 sport->gpios = mctrl_gpio_init(&sport->port, 0);
2301 if (IS_ERR(sport->gpios))
2302 return PTR_ERR(sport->gpios);
2304 sport->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
2305 if (IS_ERR(sport->clk_ipg)) {
2306 ret = PTR_ERR(sport->clk_ipg);
2307 dev_err(&pdev->dev, "failed to get ipg clk: %d\n", ret);
2311 sport->clk_per = devm_clk_get(&pdev->dev, "per");
2312 if (IS_ERR(sport->clk_per)) {
2313 ret = PTR_ERR(sport->clk_per);
2314 dev_err(&pdev->dev, "failed to get per clk: %d\n", ret);
2318 sport->port.uartclk = clk_get_rate(sport->clk_per);
2320 /* For register access, we only need to enable the ipg clock. */
2321 ret = clk_prepare_enable(sport->clk_ipg);
2323 dev_err(&pdev->dev, "failed to enable ipg clk: %d\n", ret);
2327 ret = uart_get_rs485_mode(&sport->port);
2332 * If using the i.MX UART RTS/CTS control then the RTS (CTS_B)
2333 * signal cannot be set low during transmission in case the
2334 * receiver is off (limitation of the i.MX UART IP).
2336 if (sport->port.rs485.flags & SER_RS485_ENABLED &&
2337 sport->have_rtscts && !sport->have_rtsgpio &&
2338 (!(sport->port.rs485.flags & SER_RS485_RTS_ON_SEND) &&
2339 !(sport->port.rs485.flags & SER_RS485_RX_DURING_TX)))
2341 "low-active RTS not possible when receiver is off, enabling receiver\n");
2343 /* Disable interrupts before requesting them */
2344 ucr1 = imx_uart_readl(sport, UCR1);
2345 ucr1 &= ~(UCR1_ADEN | UCR1_TRDYEN | UCR1_IDEN | UCR1_RRDYEN | UCR1_RTSDEN);
2346 imx_uart_writel(sport, ucr1, UCR1);
2348 /* Disable Ageing Timer interrupt */
2349 ucr2 = imx_uart_readl(sport, UCR2);
2351 imx_uart_writel(sport, ucr2, UCR2);
2354 * In case RS485 is enabled without GPIO RTS control, the UART IP
2355 * is used to control CTS signal. Keep both the UART and Receiver
2356 * enabled, otherwise the UART IP pulls CTS signal always HIGH no
2357 * matter how the UCR2 CTSC and CTS bits are set. To prevent any
2358 * data from being fed into the RX FIFO, enable loopback mode in
2359 * UTS register, which disconnects the RX path from external RXD
2360 * pin and connects it to the Transceiver, which is disabled, so
2361 * no data can be fed to the RX FIFO that way.
2363 if (sport->port.rs485.flags & SER_RS485_ENABLED &&
2364 sport->have_rtscts && !sport->have_rtsgpio) {
2365 uts = imx_uart_readl(sport, imx_uart_uts_reg(sport));
2367 imx_uart_writel(sport, uts, imx_uart_uts_reg(sport));
2369 ucr1 = imx_uart_readl(sport, UCR1);
2370 ucr1 |= UCR1_UARTEN;
2371 imx_uart_writel(sport, ucr1, UCR1);
2373 ucr2 = imx_uart_readl(sport, UCR2);
2375 imx_uart_writel(sport, ucr2, UCR2);
2378 if (!imx_uart_is_imx1(sport) && sport->dte_mode) {
2380 * The DCEDTE bit changes the direction of DSR, DCD, DTR and RI
2381 * and influences if UCR3_RI and UCR3_DCD changes the level of RI
2382 * and DCD (when they are outputs) or enables the respective
2383 * irqs. So set this bit early, i.e. before requesting irqs.
2385 u32 ufcr = imx_uart_readl(sport, UFCR);
2386 if (!(ufcr & UFCR_DCEDTE))
2387 imx_uart_writel(sport, ufcr | UFCR_DCEDTE, UFCR);
2390 * Disable UCR3_RI and UCR3_DCD irqs. They are also not
2391 * enabled later because they cannot be cleared
2392 * (confirmed on i.MX25) which makes them unusable.
2394 imx_uart_writel(sport,
2395 IMX21_UCR3_RXDMUXSEL | UCR3_ADNIMP | UCR3_DSR,
2399 u32 ucr3 = UCR3_DSR;
2400 u32 ufcr = imx_uart_readl(sport, UFCR);
2401 if (ufcr & UFCR_DCEDTE)
2402 imx_uart_writel(sport, ufcr & ~UFCR_DCEDTE, UFCR);
2404 if (!imx_uart_is_imx1(sport))
2405 ucr3 |= IMX21_UCR3_RXDMUXSEL | UCR3_ADNIMP;
2406 imx_uart_writel(sport, ucr3, UCR3);
2409 hrtimer_init(&sport->trigger_start_tx, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
2410 hrtimer_init(&sport->trigger_stop_tx, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
2411 sport->trigger_start_tx.function = imx_trigger_start_tx;
2412 sport->trigger_stop_tx.function = imx_trigger_stop_tx;
2415 * Allocate the IRQ(s) i.MX1 has three interrupts whereas later
2416 * chips only have one interrupt.
2419 ret = devm_request_irq(&pdev->dev, rxirq, imx_uart_rxint, 0,
2420 dev_name(&pdev->dev), sport);
2422 dev_err(&pdev->dev, "failed to request rx irq: %d\n",
2427 ret = devm_request_irq(&pdev->dev, txirq, imx_uart_txint, 0,
2428 dev_name(&pdev->dev), sport);
2430 dev_err(&pdev->dev, "failed to request tx irq: %d\n",
2435 ret = devm_request_irq(&pdev->dev, rtsirq, imx_uart_rtsint, 0,
2436 dev_name(&pdev->dev), sport);
2438 dev_err(&pdev->dev, "failed to request rts irq: %d\n",
2443 ret = devm_request_irq(&pdev->dev, rxirq, imx_uart_int, 0,
2444 dev_name(&pdev->dev), sport);
2446 dev_err(&pdev->dev, "failed to request irq: %d\n", ret);
2451 imx_uart_ports[sport->port.line] = sport;
2453 platform_set_drvdata(pdev, sport);
2455 ret = uart_add_one_port(&imx_uart_uart_driver, &sport->port);
2458 clk_disable_unprepare(sport->clk_ipg);
2463 static void imx_uart_remove(struct platform_device *pdev)
2465 struct imx_port *sport = platform_get_drvdata(pdev);
2467 uart_remove_one_port(&imx_uart_uart_driver, &sport->port);
2470 static void imx_uart_restore_context(struct imx_port *sport)
2472 unsigned long flags;
2474 uart_port_lock_irqsave(&sport->port, &flags);
2475 if (!sport->context_saved) {
2476 uart_port_unlock_irqrestore(&sport->port, flags);
2480 imx_uart_writel(sport, sport->saved_reg[4], UFCR);
2481 imx_uart_writel(sport, sport->saved_reg[5], UESC);
2482 imx_uart_writel(sport, sport->saved_reg[6], UTIM);
2483 imx_uart_writel(sport, sport->saved_reg[7], UBIR);
2484 imx_uart_writel(sport, sport->saved_reg[8], UBMR);
2485 imx_uart_writel(sport, sport->saved_reg[9], IMX21_UTS);
2486 imx_uart_writel(sport, sport->saved_reg[0], UCR1);
2487 imx_uart_writel(sport, sport->saved_reg[1] | UCR2_SRST, UCR2);
2488 imx_uart_writel(sport, sport->saved_reg[2], UCR3);
2489 imx_uart_writel(sport, sport->saved_reg[3], UCR4);
2490 sport->context_saved = false;
2491 uart_port_unlock_irqrestore(&sport->port, flags);
2494 static void imx_uart_save_context(struct imx_port *sport)
2496 unsigned long flags;
2498 /* Save necessary regs */
2499 uart_port_lock_irqsave(&sport->port, &flags);
2500 sport->saved_reg[0] = imx_uart_readl(sport, UCR1);
2501 sport->saved_reg[1] = imx_uart_readl(sport, UCR2);
2502 sport->saved_reg[2] = imx_uart_readl(sport, UCR3);
2503 sport->saved_reg[3] = imx_uart_readl(sport, UCR4);
2504 sport->saved_reg[4] = imx_uart_readl(sport, UFCR);
2505 sport->saved_reg[5] = imx_uart_readl(sport, UESC);
2506 sport->saved_reg[6] = imx_uart_readl(sport, UTIM);
2507 sport->saved_reg[7] = imx_uart_readl(sport, UBIR);
2508 sport->saved_reg[8] = imx_uart_readl(sport, UBMR);
2509 sport->saved_reg[9] = imx_uart_readl(sport, IMX21_UTS);
2510 sport->context_saved = true;
2511 uart_port_unlock_irqrestore(&sport->port, flags);
2514 static void imx_uart_enable_wakeup(struct imx_port *sport, bool on)
2518 ucr3 = imx_uart_readl(sport, UCR3);
2520 imx_uart_writel(sport, USR1_AWAKE, USR1);
2521 ucr3 |= UCR3_AWAKEN;
2523 ucr3 &= ~UCR3_AWAKEN;
2525 imx_uart_writel(sport, ucr3, UCR3);
2527 if (sport->have_rtscts) {
2528 u32 ucr1 = imx_uart_readl(sport, UCR1);
2530 imx_uart_writel(sport, USR1_RTSD, USR1);
2531 ucr1 |= UCR1_RTSDEN;
2533 ucr1 &= ~UCR1_RTSDEN;
2535 imx_uart_writel(sport, ucr1, UCR1);
2539 static int imx_uart_suspend_noirq(struct device *dev)
2541 struct imx_port *sport = dev_get_drvdata(dev);
2543 imx_uart_save_context(sport);
2545 clk_disable(sport->clk_ipg);
2547 pinctrl_pm_select_sleep_state(dev);
2552 static int imx_uart_resume_noirq(struct device *dev)
2554 struct imx_port *sport = dev_get_drvdata(dev);
2557 pinctrl_pm_select_default_state(dev);
2559 ret = clk_enable(sport->clk_ipg);
2563 imx_uart_restore_context(sport);
2568 static int imx_uart_suspend(struct device *dev)
2570 struct imx_port *sport = dev_get_drvdata(dev);
2573 uart_suspend_port(&imx_uart_uart_driver, &sport->port);
2574 disable_irq(sport->port.irq);
2576 ret = clk_prepare_enable(sport->clk_ipg);
2580 /* enable wakeup from i.MX UART */
2581 imx_uart_enable_wakeup(sport, true);
2586 static int imx_uart_resume(struct device *dev)
2588 struct imx_port *sport = dev_get_drvdata(dev);
2590 /* disable wakeup from i.MX UART */
2591 imx_uart_enable_wakeup(sport, false);
2593 uart_resume_port(&imx_uart_uart_driver, &sport->port);
2594 enable_irq(sport->port.irq);
2596 clk_disable_unprepare(sport->clk_ipg);
2601 static int imx_uart_freeze(struct device *dev)
2603 struct imx_port *sport = dev_get_drvdata(dev);
2605 uart_suspend_port(&imx_uart_uart_driver, &sport->port);
2607 return clk_prepare_enable(sport->clk_ipg);
2610 static int imx_uart_thaw(struct device *dev)
2612 struct imx_port *sport = dev_get_drvdata(dev);
2614 uart_resume_port(&imx_uart_uart_driver, &sport->port);
2616 clk_disable_unprepare(sport->clk_ipg);
2621 static const struct dev_pm_ops imx_uart_pm_ops = {
2622 .suspend_noirq = imx_uart_suspend_noirq,
2623 .resume_noirq = imx_uart_resume_noirq,
2624 .freeze_noirq = imx_uart_suspend_noirq,
2625 .thaw_noirq = imx_uart_resume_noirq,
2626 .restore_noirq = imx_uart_resume_noirq,
2627 .suspend = imx_uart_suspend,
2628 .resume = imx_uart_resume,
2629 .freeze = imx_uart_freeze,
2630 .thaw = imx_uart_thaw,
2631 .restore = imx_uart_thaw,
2634 static struct platform_driver imx_uart_platform_driver = {
2635 .probe = imx_uart_probe,
2636 .remove_new = imx_uart_remove,
2640 .of_match_table = imx_uart_dt_ids,
2641 .pm = &imx_uart_pm_ops,
2645 static int __init imx_uart_init(void)
2647 int ret = uart_register_driver(&imx_uart_uart_driver);
2652 ret = platform_driver_register(&imx_uart_platform_driver);
2654 uart_unregister_driver(&imx_uart_uart_driver);
2659 static void __exit imx_uart_exit(void)
2661 platform_driver_unregister(&imx_uart_platform_driver);
2662 uart_unregister_driver(&imx_uart_uart_driver);
2665 module_init(imx_uart_init);
2666 module_exit(imx_uart_exit);
2668 MODULE_AUTHOR("Sascha Hauer");
2669 MODULE_DESCRIPTION("IMX generic serial port driver");
2670 MODULE_LICENSE("GPL");
2671 MODULE_ALIAS("platform:imx-uart");