1 // SPDX-License-Identifier: GPL-2.0+
3 * Driver for Atmel AT91 Serial ports
4 * Copyright (C) 2003 Rick Bronson
6 * Based on drivers/char/serial_sa1100.c, by Deep Blue Solutions Ltd.
7 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
9 * DMA support added by Chip Coldwell.
11 #include <linux/tty.h>
12 #include <linux/ioport.h>
13 #include <linux/slab.h>
14 #include <linux/init.h>
15 #include <linux/serial.h>
16 #include <linux/clk.h>
17 #include <linux/console.h>
18 #include <linux/sysrq.h>
19 #include <linux/tty_flip.h>
20 #include <linux/platform_device.h>
22 #include <linux/of_device.h>
23 #include <linux/of_gpio.h>
24 #include <linux/dma-mapping.h>
25 #include <linux/dmaengine.h>
26 #include <linux/atmel_pdc.h>
27 #include <linux/uaccess.h>
28 #include <linux/platform_data/atmel.h>
29 #include <linux/timer.h>
30 #include <linux/gpio.h>
31 #include <linux/gpio/consumer.h>
32 #include <linux/err.h>
33 #include <linux/irq.h>
34 #include <linux/suspend.h>
37 #include <asm/div64.h>
39 #include <asm/ioctls.h>
41 #define PDC_BUFFER_SIZE 512
42 /* Revisit: We should calculate this based on the actual port settings */
43 #define PDC_RX_TIMEOUT (3 * 10) /* 3 bytes */
45 /* The minium number of data FIFOs should be able to contain */
46 #define ATMEL_MIN_FIFO_SIZE 8
48 * These two offsets are substracted from the RX FIFO size to define the RTS
49 * high and low thresholds
51 #define ATMEL_RTS_HIGH_OFFSET 16
52 #define ATMEL_RTS_LOW_OFFSET 20
54 #if defined(CONFIG_SERIAL_ATMEL_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
58 #include <linux/serial_core.h>
60 #include "serial_mctrl_gpio.h"
61 #include "atmel_serial.h"
63 static void atmel_start_rx(struct uart_port *port);
64 static void atmel_stop_rx(struct uart_port *port);
66 #ifdef CONFIG_SERIAL_ATMEL_TTYAT
68 /* Use device name ttyAT, major 204 and minor 154-169. This is necessary if we
69 * should coexist with the 8250 driver, such as if we have an external 16C550
71 #define SERIAL_ATMEL_MAJOR 204
72 #define MINOR_START 154
73 #define ATMEL_DEVICENAME "ttyAT"
77 /* Use device name ttyS, major 4, minor 64-68. This is the usual serial port
78 * name, but it is legally reserved for the 8250 driver. */
79 #define SERIAL_ATMEL_MAJOR TTY_MAJOR
80 #define MINOR_START 64
81 #define ATMEL_DEVICENAME "ttyS"
85 #define ATMEL_ISR_PASS_LIMIT 256
87 struct atmel_dma_buffer {
90 unsigned int dma_size;
94 struct atmel_uart_char {
100 * Be careful, the real size of the ring buffer is
101 * sizeof(atmel_uart_char) * ATMEL_SERIAL_RINGSIZE. It means that ring buffer
102 * can contain up to 1024 characters in PIO mode and up to 4096 characters in
105 #define ATMEL_SERIAL_RINGSIZE 1024
108 * at91: 6 USARTs and one DBGU port (SAM9260)
109 * samx7: 3 USARTs and 5 UARTs
111 #define ATMEL_MAX_UART 8
114 * We wrap our port structure around the generic uart_port.
116 struct atmel_uart_port {
117 struct uart_port uart; /* uart */
118 struct clk *clk; /* uart clock */
119 int may_wakeup; /* cached value of device_may_wakeup for times we need to disable it */
120 u32 backup_imr; /* IMR saved during suspend */
121 int break_active; /* break being received */
123 bool use_dma_rx; /* enable DMA receiver */
124 bool use_pdc_rx; /* enable PDC receiver */
125 short pdc_rx_idx; /* current PDC RX buffer */
126 struct atmel_dma_buffer pdc_rx[2]; /* PDC receier */
128 bool use_dma_tx; /* enable DMA transmitter */
129 bool use_pdc_tx; /* enable PDC transmitter */
130 struct atmel_dma_buffer pdc_tx; /* PDC transmitter */
132 spinlock_t lock_tx; /* port lock */
133 spinlock_t lock_rx; /* port lock */
134 struct dma_chan *chan_tx;
135 struct dma_chan *chan_rx;
136 struct dma_async_tx_descriptor *desc_tx;
137 struct dma_async_tx_descriptor *desc_rx;
138 dma_cookie_t cookie_tx;
139 dma_cookie_t cookie_rx;
140 struct scatterlist sg_tx;
141 struct scatterlist sg_rx;
142 struct tasklet_struct tasklet_rx;
143 struct tasklet_struct tasklet_tx;
144 atomic_t tasklet_shutdown;
145 unsigned int irq_status_prev;
148 struct circ_buf rx_ring;
150 struct mctrl_gpios *gpios;
151 u32 backup_mode; /* MR saved during iso7816 operations */
152 u32 backup_brgr; /* BRGR saved during iso7816 operations */
153 unsigned int tx_done_mask;
158 u32 rtor; /* address of receiver timeout register if it exists */
159 bool has_frac_baudrate;
161 struct timer_list uart_timer;
165 unsigned int pending;
166 unsigned int pending_status;
167 spinlock_t lock_suspended;
169 bool hd_start_rx; /* can start RX during half-duplex operation */
172 unsigned int fidi_min;
173 unsigned int fidi_max;
188 int (*prepare_rx)(struct uart_port *port);
189 int (*prepare_tx)(struct uart_port *port);
190 void (*schedule_rx)(struct uart_port *port);
191 void (*schedule_tx)(struct uart_port *port);
192 void (*release_rx)(struct uart_port *port);
193 void (*release_tx)(struct uart_port *port);
196 static struct atmel_uart_port atmel_ports[ATMEL_MAX_UART];
197 static DECLARE_BITMAP(atmel_ports_in_use, ATMEL_MAX_UART);
200 static struct console atmel_console;
203 #if defined(CONFIG_OF)
204 static const struct of_device_id atmel_serial_dt_ids[] = {
205 { .compatible = "atmel,at91rm9200-usart-serial" },
210 static inline struct atmel_uart_port *
211 to_atmel_uart_port(struct uart_port *uart)
213 return container_of(uart, struct atmel_uart_port, uart);
216 static inline u32 atmel_uart_readl(struct uart_port *port, u32 reg)
218 return __raw_readl(port->membase + reg);
221 static inline void atmel_uart_writel(struct uart_port *port, u32 reg, u32 value)
223 __raw_writel(value, port->membase + reg);
226 static inline u8 atmel_uart_read_char(struct uart_port *port)
228 return __raw_readb(port->membase + ATMEL_US_RHR);
231 static inline void atmel_uart_write_char(struct uart_port *port, u8 value)
233 __raw_writeb(value, port->membase + ATMEL_US_THR);
236 static inline int atmel_uart_is_half_duplex(struct uart_port *port)
238 return ((port->rs485.flags & SER_RS485_ENABLED) &&
239 !(port->rs485.flags & SER_RS485_RX_DURING_TX)) ||
240 (port->iso7816.flags & SER_ISO7816_ENABLED);
243 #ifdef CONFIG_SERIAL_ATMEL_PDC
244 static bool atmel_use_pdc_rx(struct uart_port *port)
246 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
248 return atmel_port->use_pdc_rx;
251 static bool atmel_use_pdc_tx(struct uart_port *port)
253 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
255 return atmel_port->use_pdc_tx;
258 static bool atmel_use_pdc_rx(struct uart_port *port)
263 static bool atmel_use_pdc_tx(struct uart_port *port)
269 static bool atmel_use_dma_tx(struct uart_port *port)
271 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
273 return atmel_port->use_dma_tx;
276 static bool atmel_use_dma_rx(struct uart_port *port)
278 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
280 return atmel_port->use_dma_rx;
283 static bool atmel_use_fifo(struct uart_port *port)
285 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
287 return atmel_port->fifo_size;
290 static void atmel_tasklet_schedule(struct atmel_uart_port *atmel_port,
291 struct tasklet_struct *t)
293 if (!atomic_read(&atmel_port->tasklet_shutdown))
297 /* Enable or disable the rs485 support */
298 static int atmel_config_rs485(struct uart_port *port,
299 struct serial_rs485 *rs485conf)
301 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
304 /* Disable interrupts */
305 atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask);
307 mode = atmel_uart_readl(port, ATMEL_US_MR);
309 /* Resetting serial mode to RS232 (0x0) */
310 mode &= ~ATMEL_US_USMODE;
312 port->rs485 = *rs485conf;
314 if (rs485conf->flags & SER_RS485_ENABLED) {
315 dev_dbg(port->dev, "Setting UART to RS485\n");
316 atmel_port->tx_done_mask = ATMEL_US_TXEMPTY;
317 atmel_uart_writel(port, ATMEL_US_TTGR,
318 rs485conf->delay_rts_after_send);
319 mode |= ATMEL_US_USMODE_RS485;
321 dev_dbg(port->dev, "Setting UART to RS232\n");
322 if (atmel_use_pdc_tx(port))
323 atmel_port->tx_done_mask = ATMEL_US_ENDTX |
326 atmel_port->tx_done_mask = ATMEL_US_TXRDY;
328 atmel_uart_writel(port, ATMEL_US_MR, mode);
330 /* Enable interrupts */
331 atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask);
336 static unsigned int atmel_calc_cd(struct uart_port *port,
337 struct serial_iso7816 *iso7816conf)
339 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
343 mck_rate = (u64)clk_get_rate(atmel_port->clk);
344 do_div(mck_rate, iso7816conf->clk);
349 static unsigned int atmel_calc_fidi(struct uart_port *port,
350 struct serial_iso7816 *iso7816conf)
354 if (iso7816conf->sc_fi && iso7816conf->sc_di) {
355 fidi = (u64)iso7816conf->sc_fi;
356 do_div(fidi, iso7816conf->sc_di);
361 /* Enable or disable the iso7816 support */
362 /* Called with interrupts disabled */
363 static int atmel_config_iso7816(struct uart_port *port,
364 struct serial_iso7816 *iso7816conf)
366 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
368 unsigned int cd, fidi;
371 /* Disable interrupts */
372 atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask);
374 mode = atmel_uart_readl(port, ATMEL_US_MR);
376 if (iso7816conf->flags & SER_ISO7816_ENABLED) {
377 mode &= ~ATMEL_US_USMODE;
379 if (iso7816conf->tg > 255) {
380 dev_err(port->dev, "ISO7816: Timeguard exceeding 255\n");
381 memset(iso7816conf, 0, sizeof(struct serial_iso7816));
386 if ((iso7816conf->flags & SER_ISO7816_T_PARAM)
387 == SER_ISO7816_T(0)) {
388 mode |= ATMEL_US_USMODE_ISO7816_T0 | ATMEL_US_DSNACK;
389 } else if ((iso7816conf->flags & SER_ISO7816_T_PARAM)
390 == SER_ISO7816_T(1)) {
391 mode |= ATMEL_US_USMODE_ISO7816_T1 | ATMEL_US_INACK;
393 dev_err(port->dev, "ISO7816: Type not supported\n");
394 memset(iso7816conf, 0, sizeof(struct serial_iso7816));
399 mode &= ~(ATMEL_US_USCLKS | ATMEL_US_NBSTOP | ATMEL_US_PAR);
401 /* select mck clock, and output */
402 mode |= ATMEL_US_USCLKS_MCK | ATMEL_US_CLKO;
403 /* set parity for normal/inverse mode + max iterations */
404 mode |= ATMEL_US_PAR_EVEN | ATMEL_US_NBSTOP_1 | ATMEL_US_MAX_ITER(3);
406 cd = atmel_calc_cd(port, iso7816conf);
407 fidi = atmel_calc_fidi(port, iso7816conf);
409 dev_warn(port->dev, "ISO7816 fidi = 0, Generator generates no signal\n");
410 } else if (fidi < atmel_port->fidi_min
411 || fidi > atmel_port->fidi_max) {
412 dev_err(port->dev, "ISO7816 fidi = %u, value not supported\n", fidi);
413 memset(iso7816conf, 0, sizeof(struct serial_iso7816));
418 if (!(port->iso7816.flags & SER_ISO7816_ENABLED)) {
419 /* port not yet in iso7816 mode: store configuration */
420 atmel_port->backup_mode = atmel_uart_readl(port, ATMEL_US_MR);
421 atmel_port->backup_brgr = atmel_uart_readl(port, ATMEL_US_BRGR);
424 atmel_uart_writel(port, ATMEL_US_TTGR, iso7816conf->tg);
425 atmel_uart_writel(port, ATMEL_US_BRGR, cd);
426 atmel_uart_writel(port, ATMEL_US_FIDI, fidi);
428 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXDIS | ATMEL_US_RXEN);
429 atmel_port->tx_done_mask = ATMEL_US_TXEMPTY | ATMEL_US_NACK | ATMEL_US_ITERATION;
431 dev_dbg(port->dev, "Setting UART back to RS232\n");
432 /* back to last RS232 settings */
433 mode = atmel_port->backup_mode;
434 memset(iso7816conf, 0, sizeof(struct serial_iso7816));
435 atmel_uart_writel(port, ATMEL_US_TTGR, 0);
436 atmel_uart_writel(port, ATMEL_US_BRGR, atmel_port->backup_brgr);
437 atmel_uart_writel(port, ATMEL_US_FIDI, 0x174);
439 if (atmel_use_pdc_tx(port))
440 atmel_port->tx_done_mask = ATMEL_US_ENDTX |
443 atmel_port->tx_done_mask = ATMEL_US_TXRDY;
446 port->iso7816 = *iso7816conf;
448 atmel_uart_writel(port, ATMEL_US_MR, mode);
451 /* Enable interrupts */
452 atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask);
458 * Return TIOCSER_TEMT when transmitter FIFO and Shift register is empty.
460 static u_int atmel_tx_empty(struct uart_port *port)
462 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
464 if (atmel_port->tx_stopped)
466 return (atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXEMPTY) ?
472 * Set state of the modem control output lines
474 static void atmel_set_mctrl(struct uart_port *port, u_int mctrl)
476 unsigned int control = 0;
477 unsigned int mode = atmel_uart_readl(port, ATMEL_US_MR);
478 unsigned int rts_paused, rts_ready;
479 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
481 /* override mode to RS485 if needed, otherwise keep the current mode */
482 if (port->rs485.flags & SER_RS485_ENABLED) {
483 atmel_uart_writel(port, ATMEL_US_TTGR,
484 port->rs485.delay_rts_after_send);
485 mode &= ~ATMEL_US_USMODE;
486 mode |= ATMEL_US_USMODE_RS485;
489 /* set the RTS line state according to the mode */
490 if ((mode & ATMEL_US_USMODE) == ATMEL_US_USMODE_HWHS) {
491 /* force RTS line to high level */
492 rts_paused = ATMEL_US_RTSEN;
494 /* give the control of the RTS line back to the hardware */
495 rts_ready = ATMEL_US_RTSDIS;
497 /* force RTS line to high level */
498 rts_paused = ATMEL_US_RTSDIS;
500 /* force RTS line to low level */
501 rts_ready = ATMEL_US_RTSEN;
504 if (mctrl & TIOCM_RTS)
505 control |= rts_ready;
507 control |= rts_paused;
509 if (mctrl & TIOCM_DTR)
510 control |= ATMEL_US_DTREN;
512 control |= ATMEL_US_DTRDIS;
514 atmel_uart_writel(port, ATMEL_US_CR, control);
516 mctrl_gpio_set(atmel_port->gpios, mctrl);
518 /* Local loopback mode? */
519 mode &= ~ATMEL_US_CHMODE;
520 if (mctrl & TIOCM_LOOP)
521 mode |= ATMEL_US_CHMODE_LOC_LOOP;
523 mode |= ATMEL_US_CHMODE_NORMAL;
525 atmel_uart_writel(port, ATMEL_US_MR, mode);
529 * Get state of the modem control input lines
531 static u_int atmel_get_mctrl(struct uart_port *port)
533 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
534 unsigned int ret = 0, status;
536 status = atmel_uart_readl(port, ATMEL_US_CSR);
539 * The control signals are active low.
541 if (!(status & ATMEL_US_DCD))
543 if (!(status & ATMEL_US_CTS))
545 if (!(status & ATMEL_US_DSR))
547 if (!(status & ATMEL_US_RI))
550 return mctrl_gpio_get(atmel_port->gpios, &ret);
556 static void atmel_stop_tx(struct uart_port *port)
558 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
560 if (atmel_use_pdc_tx(port)) {
561 /* disable PDC transmit */
562 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTDIS);
566 * Disable the transmitter.
567 * This is mandatory when DMA is used, otherwise the DMA buffer
568 * is fully transmitted.
570 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXDIS);
571 atmel_port->tx_stopped = true;
573 /* Disable interrupts */
574 atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask);
576 if (atmel_uart_is_half_duplex(port))
577 atmel_start_rx(port);
582 * Start transmitting.
584 static void atmel_start_tx(struct uart_port *port)
586 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
588 if (atmel_use_pdc_tx(port) && (atmel_uart_readl(port, ATMEL_PDC_PTSR)
590 /* The transmitter is already running. Yes, we
594 if (atmel_use_pdc_tx(port) || atmel_use_dma_tx(port))
595 if (atmel_uart_is_half_duplex(port))
598 if (atmel_use_pdc_tx(port))
599 /* re-enable PDC transmit */
600 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTEN);
602 /* Enable interrupts */
603 atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask);
605 /* re-enable the transmitter */
606 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN);
607 atmel_port->tx_stopped = false;
611 * start receiving - port is in process of being opened.
613 static void atmel_start_rx(struct uart_port *port)
615 /* reset status and receiver */
616 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA);
618 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RXEN);
620 if (atmel_use_pdc_rx(port)) {
621 /* enable PDC controller */
622 atmel_uart_writel(port, ATMEL_US_IER,
623 ATMEL_US_ENDRX | ATMEL_US_TIMEOUT |
624 port->read_status_mask);
625 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_RXTEN);
627 atmel_uart_writel(port, ATMEL_US_IER, ATMEL_US_RXRDY);
632 * Stop receiving - port is in process of being closed.
634 static void atmel_stop_rx(struct uart_port *port)
636 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RXDIS);
638 if (atmel_use_pdc_rx(port)) {
639 /* disable PDC receive */
640 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_RXTDIS);
641 atmel_uart_writel(port, ATMEL_US_IDR,
642 ATMEL_US_ENDRX | ATMEL_US_TIMEOUT |
643 port->read_status_mask);
645 atmel_uart_writel(port, ATMEL_US_IDR, ATMEL_US_RXRDY);
650 * Enable modem status interrupts
652 static void atmel_enable_ms(struct uart_port *port)
654 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
658 * Interrupt should not be enabled twice
660 if (atmel_port->ms_irq_enabled)
663 atmel_port->ms_irq_enabled = true;
665 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS))
666 ier |= ATMEL_US_CTSIC;
668 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_DSR))
669 ier |= ATMEL_US_DSRIC;
671 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_RI))
672 ier |= ATMEL_US_RIIC;
674 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_DCD))
675 ier |= ATMEL_US_DCDIC;
677 atmel_uart_writel(port, ATMEL_US_IER, ier);
679 mctrl_gpio_enable_ms(atmel_port->gpios);
683 * Disable modem status interrupts
685 static void atmel_disable_ms(struct uart_port *port)
687 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
691 * Interrupt should not be disabled twice
693 if (!atmel_port->ms_irq_enabled)
696 atmel_port->ms_irq_enabled = false;
698 mctrl_gpio_disable_ms(atmel_port->gpios);
700 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS))
701 idr |= ATMEL_US_CTSIC;
703 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_DSR))
704 idr |= ATMEL_US_DSRIC;
706 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_RI))
707 idr |= ATMEL_US_RIIC;
709 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_DCD))
710 idr |= ATMEL_US_DCDIC;
712 atmel_uart_writel(port, ATMEL_US_IDR, idr);
716 * Control the transmission of a break signal
718 static void atmel_break_ctl(struct uart_port *port, int break_state)
720 if (break_state != 0)
722 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STTBRK);
725 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STPBRK);
729 * Stores the incoming character in the ring buffer
732 atmel_buffer_rx_char(struct uart_port *port, unsigned int status,
735 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
736 struct circ_buf *ring = &atmel_port->rx_ring;
737 struct atmel_uart_char *c;
739 if (!CIRC_SPACE(ring->head, ring->tail, ATMEL_SERIAL_RINGSIZE))
740 /* Buffer overflow, ignore char */
743 c = &((struct atmel_uart_char *)ring->buf)[ring->head];
747 /* Make sure the character is stored before we update head. */
750 ring->head = (ring->head + 1) & (ATMEL_SERIAL_RINGSIZE - 1);
754 * Deal with parity, framing and overrun errors.
756 static void atmel_pdc_rxerr(struct uart_port *port, unsigned int status)
759 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA);
761 if (status & ATMEL_US_RXBRK) {
762 /* ignore side-effect */
763 status &= ~(ATMEL_US_PARE | ATMEL_US_FRAME);
766 if (status & ATMEL_US_PARE)
767 port->icount.parity++;
768 if (status & ATMEL_US_FRAME)
769 port->icount.frame++;
770 if (status & ATMEL_US_OVRE)
771 port->icount.overrun++;
775 * Characters received (called from interrupt handler)
777 static void atmel_rx_chars(struct uart_port *port)
779 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
780 unsigned int status, ch;
782 status = atmel_uart_readl(port, ATMEL_US_CSR);
783 while (status & ATMEL_US_RXRDY) {
784 ch = atmel_uart_read_char(port);
787 * note that the error handling code is
788 * out of the main execution path
790 if (unlikely(status & (ATMEL_US_PARE | ATMEL_US_FRAME
791 | ATMEL_US_OVRE | ATMEL_US_RXBRK)
792 || atmel_port->break_active)) {
795 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA);
797 if (status & ATMEL_US_RXBRK
798 && !atmel_port->break_active) {
799 atmel_port->break_active = 1;
800 atmel_uart_writel(port, ATMEL_US_IER,
804 * This is either the end-of-break
805 * condition or we've received at
806 * least one character without RXBRK
807 * being set. In both cases, the next
808 * RXBRK will indicate start-of-break.
810 atmel_uart_writel(port, ATMEL_US_IDR,
812 status &= ~ATMEL_US_RXBRK;
813 atmel_port->break_active = 0;
817 atmel_buffer_rx_char(port, status, ch);
818 status = atmel_uart_readl(port, ATMEL_US_CSR);
821 atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_rx);
825 * Transmit characters (called from tasklet with TXRDY interrupt
828 static void atmel_tx_chars(struct uart_port *port)
830 struct circ_buf *xmit = &port->state->xmit;
831 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
834 (atmel_uart_readl(port, ATMEL_US_CSR) & atmel_port->tx_done_mask)) {
835 atmel_uart_write_char(port, port->x_char);
839 if (uart_circ_empty(xmit) || uart_tx_stopped(port))
842 while (atmel_uart_readl(port, ATMEL_US_CSR) &
843 atmel_port->tx_done_mask) {
844 atmel_uart_write_char(port, xmit->buf[xmit->tail]);
845 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
847 if (uart_circ_empty(xmit))
851 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
852 uart_write_wakeup(port);
854 if (!uart_circ_empty(xmit))
855 /* Enable interrupts */
856 atmel_uart_writel(port, ATMEL_US_IER,
857 atmel_port->tx_done_mask);
860 static void atmel_complete_tx_dma(void *arg)
862 struct atmel_uart_port *atmel_port = arg;
863 struct uart_port *port = &atmel_port->uart;
864 struct circ_buf *xmit = &port->state->xmit;
865 struct dma_chan *chan = atmel_port->chan_tx;
868 spin_lock_irqsave(&port->lock, flags);
871 dmaengine_terminate_all(chan);
872 xmit->tail += atmel_port->tx_len;
873 xmit->tail &= UART_XMIT_SIZE - 1;
875 port->icount.tx += atmel_port->tx_len;
877 spin_lock_irq(&atmel_port->lock_tx);
878 async_tx_ack(atmel_port->desc_tx);
879 atmel_port->cookie_tx = -EINVAL;
880 atmel_port->desc_tx = NULL;
881 spin_unlock_irq(&atmel_port->lock_tx);
883 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
884 uart_write_wakeup(port);
887 * xmit is a circular buffer so, if we have just send data from
888 * xmit->tail to the end of xmit->buf, now we have to transmit the
889 * remaining data from the beginning of xmit->buf to xmit->head.
891 if (!uart_circ_empty(xmit))
892 atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_tx);
893 else if (atmel_uart_is_half_duplex(port)) {
895 * DMA done, re-enable TXEMPTY and signal that we can stop
896 * TX and start RX for RS485
898 atmel_port->hd_start_rx = true;
899 atmel_uart_writel(port, ATMEL_US_IER,
900 atmel_port->tx_done_mask);
903 spin_unlock_irqrestore(&port->lock, flags);
906 static void atmel_release_tx_dma(struct uart_port *port)
908 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
909 struct dma_chan *chan = atmel_port->chan_tx;
912 dmaengine_terminate_all(chan);
913 dma_release_channel(chan);
914 dma_unmap_sg(port->dev, &atmel_port->sg_tx, 1,
918 atmel_port->desc_tx = NULL;
919 atmel_port->chan_tx = NULL;
920 atmel_port->cookie_tx = -EINVAL;
924 * Called from tasklet with TXRDY interrupt is disabled.
926 static void atmel_tx_dma(struct uart_port *port)
928 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
929 struct circ_buf *xmit = &port->state->xmit;
930 struct dma_chan *chan = atmel_port->chan_tx;
931 struct dma_async_tx_descriptor *desc;
932 struct scatterlist sgl[2], *sg, *sg_tx = &atmel_port->sg_tx;
933 unsigned int tx_len, part1_len, part2_len, sg_len;
934 dma_addr_t phys_addr;
936 /* Make sure we have an idle channel */
937 if (atmel_port->desc_tx != NULL)
940 if (!uart_circ_empty(xmit) && !uart_tx_stopped(port)) {
943 * Port xmit buffer is already mapped,
944 * and it is one page... Just adjust
945 * offsets and lengths. Since it is a circular buffer,
946 * we have to transmit till the end, and then the rest.
947 * Take the port lock to get a
948 * consistent xmit buffer state.
950 tx_len = CIRC_CNT_TO_END(xmit->head,
954 if (atmel_port->fifo_size) {
955 /* multi data mode */
956 part1_len = (tx_len & ~0x3); /* DWORD access */
957 part2_len = (tx_len & 0x3); /* BYTE access */
959 /* single data (legacy) mode */
961 part2_len = tx_len; /* BYTE access only */
964 sg_init_table(sgl, 2);
966 phys_addr = sg_dma_address(sg_tx) + xmit->tail;
969 sg_dma_address(sg) = phys_addr;
970 sg_dma_len(sg) = part1_len;
972 phys_addr += part1_len;
977 sg_dma_address(sg) = phys_addr;
978 sg_dma_len(sg) = part2_len;
982 * save tx_len so atmel_complete_tx_dma() will increase
983 * xmit->tail correctly
985 atmel_port->tx_len = tx_len;
987 desc = dmaengine_prep_slave_sg(chan,
994 dev_err(port->dev, "Failed to send via dma!\n");
998 dma_sync_sg_for_device(port->dev, sg_tx, 1, DMA_TO_DEVICE);
1000 atmel_port->desc_tx = desc;
1001 desc->callback = atmel_complete_tx_dma;
1002 desc->callback_param = atmel_port;
1003 atmel_port->cookie_tx = dmaengine_submit(desc);
1006 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
1007 uart_write_wakeup(port);
1010 static int atmel_prepare_tx_dma(struct uart_port *port)
1012 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1013 struct device *mfd_dev = port->dev->parent;
1014 dma_cap_mask_t mask;
1015 struct dma_slave_config config;
1019 dma_cap_set(DMA_SLAVE, mask);
1021 atmel_port->chan_tx = dma_request_slave_channel(mfd_dev, "tx");
1022 if (atmel_port->chan_tx == NULL)
1024 dev_info(port->dev, "using %s for tx DMA transfers\n",
1025 dma_chan_name(atmel_port->chan_tx));
1027 spin_lock_init(&atmel_port->lock_tx);
1028 sg_init_table(&atmel_port->sg_tx, 1);
1029 /* UART circular tx buffer is an aligned page. */
1030 BUG_ON(!PAGE_ALIGNED(port->state->xmit.buf));
1031 sg_set_page(&atmel_port->sg_tx,
1032 virt_to_page(port->state->xmit.buf),
1034 offset_in_page(port->state->xmit.buf));
1035 nent = dma_map_sg(port->dev,
1041 dev_dbg(port->dev, "need to release resource of dma\n");
1044 dev_dbg(port->dev, "%s: mapped %d@%p to %pad\n", __func__,
1045 sg_dma_len(&atmel_port->sg_tx),
1046 port->state->xmit.buf,
1047 &sg_dma_address(&atmel_port->sg_tx));
1050 /* Configure the slave DMA */
1051 memset(&config, 0, sizeof(config));
1052 config.direction = DMA_MEM_TO_DEV;
1053 config.dst_addr_width = (atmel_port->fifo_size) ?
1054 DMA_SLAVE_BUSWIDTH_4_BYTES :
1055 DMA_SLAVE_BUSWIDTH_1_BYTE;
1056 config.dst_addr = port->mapbase + ATMEL_US_THR;
1057 config.dst_maxburst = 1;
1059 ret = dmaengine_slave_config(atmel_port->chan_tx,
1062 dev_err(port->dev, "DMA tx slave configuration failed\n");
1069 dev_err(port->dev, "TX channel not available, switch to pio\n");
1070 atmel_port->use_dma_tx = 0;
1071 if (atmel_port->chan_tx)
1072 atmel_release_tx_dma(port);
1076 static void atmel_complete_rx_dma(void *arg)
1078 struct uart_port *port = arg;
1079 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1081 atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_rx);
1084 static void atmel_release_rx_dma(struct uart_port *port)
1086 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1087 struct dma_chan *chan = atmel_port->chan_rx;
1090 dmaengine_terminate_all(chan);
1091 dma_release_channel(chan);
1092 dma_unmap_sg(port->dev, &atmel_port->sg_rx, 1,
1096 atmel_port->desc_rx = NULL;
1097 atmel_port->chan_rx = NULL;
1098 atmel_port->cookie_rx = -EINVAL;
1101 static void atmel_rx_from_dma(struct uart_port *port)
1103 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1104 struct tty_port *tport = &port->state->port;
1105 struct circ_buf *ring = &atmel_port->rx_ring;
1106 struct dma_chan *chan = atmel_port->chan_rx;
1107 struct dma_tx_state state;
1108 enum dma_status dmastat;
1112 /* Reset the UART timeout early so that we don't miss one */
1113 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STTTO);
1114 dmastat = dmaengine_tx_status(chan,
1115 atmel_port->cookie_rx,
1117 /* Restart a new tasklet if DMA status is error */
1118 if (dmastat == DMA_ERROR) {
1119 dev_dbg(port->dev, "Get residue error, restart tasklet\n");
1120 atmel_uart_writel(port, ATMEL_US_IER, ATMEL_US_TIMEOUT);
1121 atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_rx);
1125 /* CPU claims ownership of RX DMA buffer */
1126 dma_sync_sg_for_cpu(port->dev,
1132 * ring->head points to the end of data already written by the DMA.
1133 * ring->tail points to the beginning of data to be read by the
1135 * The current transfer size should not be larger than the dma buffer
1138 ring->head = sg_dma_len(&atmel_port->sg_rx) - state.residue;
1139 BUG_ON(ring->head > sg_dma_len(&atmel_port->sg_rx));
1141 * At this point ring->head may point to the first byte right after the
1142 * last byte of the dma buffer:
1143 * 0 <= ring->head <= sg_dma_len(&atmel_port->sg_rx)
1145 * However ring->tail must always points inside the dma buffer:
1146 * 0 <= ring->tail <= sg_dma_len(&atmel_port->sg_rx) - 1
1148 * Since we use a ring buffer, we have to handle the case
1149 * where head is lower than tail. In such a case, we first read from
1150 * tail to the end of the buffer then reset tail.
1152 if (ring->head < ring->tail) {
1153 count = sg_dma_len(&atmel_port->sg_rx) - ring->tail;
1155 tty_insert_flip_string(tport, ring->buf + ring->tail, count);
1157 port->icount.rx += count;
1160 /* Finally we read data from tail to head */
1161 if (ring->tail < ring->head) {
1162 count = ring->head - ring->tail;
1164 tty_insert_flip_string(tport, ring->buf + ring->tail, count);
1165 /* Wrap ring->head if needed */
1166 if (ring->head >= sg_dma_len(&atmel_port->sg_rx))
1168 ring->tail = ring->head;
1169 port->icount.rx += count;
1172 /* USART retreives ownership of RX DMA buffer */
1173 dma_sync_sg_for_device(port->dev,
1179 * Drop the lock here since it might end up calling
1180 * uart_start(), which takes the lock.
1182 spin_unlock(&port->lock);
1183 tty_flip_buffer_push(tport);
1184 spin_lock(&port->lock);
1186 atmel_uart_writel(port, ATMEL_US_IER, ATMEL_US_TIMEOUT);
1189 static int atmel_prepare_rx_dma(struct uart_port *port)
1191 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1192 struct device *mfd_dev = port->dev->parent;
1193 struct dma_async_tx_descriptor *desc;
1194 dma_cap_mask_t mask;
1195 struct dma_slave_config config;
1196 struct circ_buf *ring;
1199 ring = &atmel_port->rx_ring;
1202 dma_cap_set(DMA_CYCLIC, mask);
1204 atmel_port->chan_rx = dma_request_slave_channel(mfd_dev, "rx");
1205 if (atmel_port->chan_rx == NULL)
1207 dev_info(port->dev, "using %s for rx DMA transfers\n",
1208 dma_chan_name(atmel_port->chan_rx));
1210 spin_lock_init(&atmel_port->lock_rx);
1211 sg_init_table(&atmel_port->sg_rx, 1);
1212 /* UART circular rx buffer is an aligned page. */
1213 BUG_ON(!PAGE_ALIGNED(ring->buf));
1214 sg_set_page(&atmel_port->sg_rx,
1215 virt_to_page(ring->buf),
1216 sizeof(struct atmel_uart_char) * ATMEL_SERIAL_RINGSIZE,
1217 offset_in_page(ring->buf));
1218 nent = dma_map_sg(port->dev,
1224 dev_dbg(port->dev, "need to release resource of dma\n");
1227 dev_dbg(port->dev, "%s: mapped %d@%p to %pad\n", __func__,
1228 sg_dma_len(&atmel_port->sg_rx),
1230 &sg_dma_address(&atmel_port->sg_rx));
1233 /* Configure the slave DMA */
1234 memset(&config, 0, sizeof(config));
1235 config.direction = DMA_DEV_TO_MEM;
1236 config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1237 config.src_addr = port->mapbase + ATMEL_US_RHR;
1238 config.src_maxburst = 1;
1240 ret = dmaengine_slave_config(atmel_port->chan_rx,
1243 dev_err(port->dev, "DMA rx slave configuration failed\n");
1247 * Prepare a cyclic dma transfer, assign 2 descriptors,
1248 * each one is half ring buffer size
1250 desc = dmaengine_prep_dma_cyclic(atmel_port->chan_rx,
1251 sg_dma_address(&atmel_port->sg_rx),
1252 sg_dma_len(&atmel_port->sg_rx),
1253 sg_dma_len(&atmel_port->sg_rx)/2,
1255 DMA_PREP_INTERRUPT);
1257 dev_err(port->dev, "Preparing DMA cyclic failed\n");
1260 desc->callback = atmel_complete_rx_dma;
1261 desc->callback_param = port;
1262 atmel_port->desc_rx = desc;
1263 atmel_port->cookie_rx = dmaengine_submit(desc);
1268 dev_err(port->dev, "RX channel not available, switch to pio\n");
1269 atmel_port->use_dma_rx = 0;
1270 if (atmel_port->chan_rx)
1271 atmel_release_rx_dma(port);
1275 static void atmel_uart_timer_callback(struct timer_list *t)
1277 struct atmel_uart_port *atmel_port = from_timer(atmel_port, t,
1279 struct uart_port *port = &atmel_port->uart;
1281 if (!atomic_read(&atmel_port->tasklet_shutdown)) {
1282 tasklet_schedule(&atmel_port->tasklet_rx);
1283 mod_timer(&atmel_port->uart_timer,
1284 jiffies + uart_poll_timeout(port));
1289 * receive interrupt handler.
1292 atmel_handle_receive(struct uart_port *port, unsigned int pending)
1294 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1296 if (atmel_use_pdc_rx(port)) {
1298 * PDC receive. Just schedule the tasklet and let it
1299 * figure out the details.
1301 * TODO: We're not handling error flags correctly at
1304 if (pending & (ATMEL_US_ENDRX | ATMEL_US_TIMEOUT)) {
1305 atmel_uart_writel(port, ATMEL_US_IDR,
1306 (ATMEL_US_ENDRX | ATMEL_US_TIMEOUT));
1307 atmel_tasklet_schedule(atmel_port,
1308 &atmel_port->tasklet_rx);
1311 if (pending & (ATMEL_US_RXBRK | ATMEL_US_OVRE |
1312 ATMEL_US_FRAME | ATMEL_US_PARE))
1313 atmel_pdc_rxerr(port, pending);
1316 if (atmel_use_dma_rx(port)) {
1317 if (pending & ATMEL_US_TIMEOUT) {
1318 atmel_uart_writel(port, ATMEL_US_IDR,
1320 atmel_tasklet_schedule(atmel_port,
1321 &atmel_port->tasklet_rx);
1325 /* Interrupt receive */
1326 if (pending & ATMEL_US_RXRDY)
1327 atmel_rx_chars(port);
1328 else if (pending & ATMEL_US_RXBRK) {
1330 * End of break detected. If it came along with a
1331 * character, atmel_rx_chars will handle it.
1333 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA);
1334 atmel_uart_writel(port, ATMEL_US_IDR, ATMEL_US_RXBRK);
1335 atmel_port->break_active = 0;
1340 * transmit interrupt handler. (Transmit is IRQF_NODELAY safe)
1343 atmel_handle_transmit(struct uart_port *port, unsigned int pending)
1345 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1347 if (pending & atmel_port->tx_done_mask) {
1348 atmel_uart_writel(port, ATMEL_US_IDR,
1349 atmel_port->tx_done_mask);
1351 /* Start RX if flag was set and FIFO is empty */
1352 if (atmel_port->hd_start_rx) {
1353 if (!(atmel_uart_readl(port, ATMEL_US_CSR)
1354 & ATMEL_US_TXEMPTY))
1355 dev_warn(port->dev, "Should start RX, but TX fifo is not empty\n");
1357 atmel_port->hd_start_rx = false;
1358 atmel_start_rx(port);
1361 atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_tx);
1366 * status flags interrupt handler.
1369 atmel_handle_status(struct uart_port *port, unsigned int pending,
1370 unsigned int status)
1372 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1373 unsigned int status_change;
1375 if (pending & (ATMEL_US_RIIC | ATMEL_US_DSRIC | ATMEL_US_DCDIC
1376 | ATMEL_US_CTSIC)) {
1377 status_change = status ^ atmel_port->irq_status_prev;
1378 atmel_port->irq_status_prev = status;
1380 if (status_change & (ATMEL_US_RI | ATMEL_US_DSR
1381 | ATMEL_US_DCD | ATMEL_US_CTS)) {
1382 /* TODO: All reads to CSR will clear these interrupts! */
1383 if (status_change & ATMEL_US_RI)
1385 if (status_change & ATMEL_US_DSR)
1387 if (status_change & ATMEL_US_DCD)
1388 uart_handle_dcd_change(port, !(status & ATMEL_US_DCD));
1389 if (status_change & ATMEL_US_CTS)
1390 uart_handle_cts_change(port, !(status & ATMEL_US_CTS));
1392 wake_up_interruptible(&port->state->port.delta_msr_wait);
1396 if (pending & (ATMEL_US_NACK | ATMEL_US_ITERATION))
1397 dev_dbg(port->dev, "ISO7816 ERROR (0x%08x)\n", pending);
1403 static irqreturn_t atmel_interrupt(int irq, void *dev_id)
1405 struct uart_port *port = dev_id;
1406 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1407 unsigned int status, pending, mask, pass_counter = 0;
1409 spin_lock(&atmel_port->lock_suspended);
1412 status = atmel_uart_readl(port, ATMEL_US_CSR);
1413 mask = atmel_uart_readl(port, ATMEL_US_IMR);
1414 pending = status & mask;
1418 if (atmel_port->suspended) {
1419 atmel_port->pending |= pending;
1420 atmel_port->pending_status = status;
1421 atmel_uart_writel(port, ATMEL_US_IDR, mask);
1426 atmel_handle_receive(port, pending);
1427 atmel_handle_status(port, pending, status);
1428 atmel_handle_transmit(port, pending);
1429 } while (pass_counter++ < ATMEL_ISR_PASS_LIMIT);
1431 spin_unlock(&atmel_port->lock_suspended);
1433 return pass_counter ? IRQ_HANDLED : IRQ_NONE;
1436 static void atmel_release_tx_pdc(struct uart_port *port)
1438 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1439 struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;
1441 dma_unmap_single(port->dev,
1448 * Called from tasklet with ENDTX and TXBUFE interrupts disabled.
1450 static void atmel_tx_pdc(struct uart_port *port)
1452 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1453 struct circ_buf *xmit = &port->state->xmit;
1454 struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;
1457 /* nothing left to transmit? */
1458 if (atmel_uart_readl(port, ATMEL_PDC_TCR))
1461 xmit->tail += pdc->ofs;
1462 xmit->tail &= UART_XMIT_SIZE - 1;
1464 port->icount.tx += pdc->ofs;
1467 /* more to transmit - setup next transfer */
1469 /* disable PDC transmit */
1470 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTDIS);
1472 if (!uart_circ_empty(xmit) && !uart_tx_stopped(port)) {
1473 dma_sync_single_for_device(port->dev,
1478 count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
1481 atmel_uart_writel(port, ATMEL_PDC_TPR,
1482 pdc->dma_addr + xmit->tail);
1483 atmel_uart_writel(port, ATMEL_PDC_TCR, count);
1484 /* re-enable PDC transmit */
1485 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTEN);
1486 /* Enable interrupts */
1487 atmel_uart_writel(port, ATMEL_US_IER,
1488 atmel_port->tx_done_mask);
1490 if (atmel_uart_is_half_duplex(port)) {
1491 /* DMA done, stop TX, start RX for RS485 */
1492 atmel_start_rx(port);
1496 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
1497 uart_write_wakeup(port);
1500 static int atmel_prepare_tx_pdc(struct uart_port *port)
1502 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1503 struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;
1504 struct circ_buf *xmit = &port->state->xmit;
1506 pdc->buf = xmit->buf;
1507 pdc->dma_addr = dma_map_single(port->dev,
1511 pdc->dma_size = UART_XMIT_SIZE;
1517 static void atmel_rx_from_ring(struct uart_port *port)
1519 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1520 struct circ_buf *ring = &atmel_port->rx_ring;
1522 unsigned int status;
1524 while (ring->head != ring->tail) {
1525 struct atmel_uart_char c;
1527 /* Make sure c is loaded after head. */
1530 c = ((struct atmel_uart_char *)ring->buf)[ring->tail];
1532 ring->tail = (ring->tail + 1) & (ATMEL_SERIAL_RINGSIZE - 1);
1539 * note that the error handling code is
1540 * out of the main execution path
1542 if (unlikely(status & (ATMEL_US_PARE | ATMEL_US_FRAME
1543 | ATMEL_US_OVRE | ATMEL_US_RXBRK))) {
1544 if (status & ATMEL_US_RXBRK) {
1545 /* ignore side-effect */
1546 status &= ~(ATMEL_US_PARE | ATMEL_US_FRAME);
1549 if (uart_handle_break(port))
1552 if (status & ATMEL_US_PARE)
1553 port->icount.parity++;
1554 if (status & ATMEL_US_FRAME)
1555 port->icount.frame++;
1556 if (status & ATMEL_US_OVRE)
1557 port->icount.overrun++;
1559 status &= port->read_status_mask;
1561 if (status & ATMEL_US_RXBRK)
1563 else if (status & ATMEL_US_PARE)
1565 else if (status & ATMEL_US_FRAME)
1570 if (uart_handle_sysrq_char(port, c.ch))
1573 uart_insert_char(port, status, ATMEL_US_OVRE, c.ch, flg);
1577 * Drop the lock here since it might end up calling
1578 * uart_start(), which takes the lock.
1580 spin_unlock(&port->lock);
1581 tty_flip_buffer_push(&port->state->port);
1582 spin_lock(&port->lock);
1585 static void atmel_release_rx_pdc(struct uart_port *port)
1587 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1590 for (i = 0; i < 2; i++) {
1591 struct atmel_dma_buffer *pdc = &atmel_port->pdc_rx[i];
1593 dma_unmap_single(port->dev,
1601 static void atmel_rx_from_pdc(struct uart_port *port)
1603 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1604 struct tty_port *tport = &port->state->port;
1605 struct atmel_dma_buffer *pdc;
1606 int rx_idx = atmel_port->pdc_rx_idx;
1612 /* Reset the UART timeout early so that we don't miss one */
1613 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STTTO);
1615 pdc = &atmel_port->pdc_rx[rx_idx];
1616 head = atmel_uart_readl(port, ATMEL_PDC_RPR) - pdc->dma_addr;
1619 /* If the PDC has switched buffers, RPR won't contain
1620 * any address within the current buffer. Since head
1621 * is unsigned, we just need a one-way comparison to
1624 * In this case, we just need to consume the entire
1625 * buffer and resubmit it for DMA. This will clear the
1626 * ENDRX bit as well, so that we can safely re-enable
1627 * all interrupts below.
1629 head = min(head, pdc->dma_size);
1631 if (likely(head != tail)) {
1632 dma_sync_single_for_cpu(port->dev, pdc->dma_addr,
1633 pdc->dma_size, DMA_FROM_DEVICE);
1636 * head will only wrap around when we recycle
1637 * the DMA buffer, and when that happens, we
1638 * explicitly set tail to 0. So head will
1639 * always be greater than tail.
1641 count = head - tail;
1643 tty_insert_flip_string(tport, pdc->buf + pdc->ofs,
1646 dma_sync_single_for_device(port->dev, pdc->dma_addr,
1647 pdc->dma_size, DMA_FROM_DEVICE);
1649 port->icount.rx += count;
1654 * If the current buffer is full, we need to check if
1655 * the next one contains any additional data.
1657 if (head >= pdc->dma_size) {
1659 atmel_uart_writel(port, ATMEL_PDC_RNPR, pdc->dma_addr);
1660 atmel_uart_writel(port, ATMEL_PDC_RNCR, pdc->dma_size);
1663 atmel_port->pdc_rx_idx = rx_idx;
1665 } while (head >= pdc->dma_size);
1668 * Drop the lock here since it might end up calling
1669 * uart_start(), which takes the lock.
1671 spin_unlock(&port->lock);
1672 tty_flip_buffer_push(tport);
1673 spin_lock(&port->lock);
1675 atmel_uart_writel(port, ATMEL_US_IER,
1676 ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);
1679 static int atmel_prepare_rx_pdc(struct uart_port *port)
1681 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1684 for (i = 0; i < 2; i++) {
1685 struct atmel_dma_buffer *pdc = &atmel_port->pdc_rx[i];
1687 pdc->buf = kmalloc(PDC_BUFFER_SIZE, GFP_KERNEL);
1688 if (pdc->buf == NULL) {
1690 dma_unmap_single(port->dev,
1691 atmel_port->pdc_rx[0].dma_addr,
1694 kfree(atmel_port->pdc_rx[0].buf);
1696 atmel_port->use_pdc_rx = 0;
1699 pdc->dma_addr = dma_map_single(port->dev,
1703 pdc->dma_size = PDC_BUFFER_SIZE;
1707 atmel_port->pdc_rx_idx = 0;
1709 atmel_uart_writel(port, ATMEL_PDC_RPR, atmel_port->pdc_rx[0].dma_addr);
1710 atmel_uart_writel(port, ATMEL_PDC_RCR, PDC_BUFFER_SIZE);
1712 atmel_uart_writel(port, ATMEL_PDC_RNPR,
1713 atmel_port->pdc_rx[1].dma_addr);
1714 atmel_uart_writel(port, ATMEL_PDC_RNCR, PDC_BUFFER_SIZE);
1720 * tasklet handling tty stuff outside the interrupt handler.
1722 static void atmel_tasklet_rx_func(unsigned long data)
1724 struct uart_port *port = (struct uart_port *)data;
1725 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1727 /* The interrupt handler does not take the lock */
1728 spin_lock(&port->lock);
1729 atmel_port->schedule_rx(port);
1730 spin_unlock(&port->lock);
1733 static void atmel_tasklet_tx_func(unsigned long data)
1735 struct uart_port *port = (struct uart_port *)data;
1736 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1738 /* The interrupt handler does not take the lock */
1739 spin_lock(&port->lock);
1740 atmel_port->schedule_tx(port);
1741 spin_unlock(&port->lock);
1744 static void atmel_init_property(struct atmel_uart_port *atmel_port,
1745 struct platform_device *pdev)
1747 struct device_node *np = pdev->dev.of_node;
1749 /* DMA/PDC usage specification */
1750 if (of_property_read_bool(np, "atmel,use-dma-rx")) {
1751 if (of_property_read_bool(np, "dmas")) {
1752 atmel_port->use_dma_rx = true;
1753 atmel_port->use_pdc_rx = false;
1755 atmel_port->use_dma_rx = false;
1756 atmel_port->use_pdc_rx = true;
1759 atmel_port->use_dma_rx = false;
1760 atmel_port->use_pdc_rx = false;
1763 if (of_property_read_bool(np, "atmel,use-dma-tx")) {
1764 if (of_property_read_bool(np, "dmas")) {
1765 atmel_port->use_dma_tx = true;
1766 atmel_port->use_pdc_tx = false;
1768 atmel_port->use_dma_tx = false;
1769 atmel_port->use_pdc_tx = true;
1772 atmel_port->use_dma_tx = false;
1773 atmel_port->use_pdc_tx = false;
1777 static void atmel_set_ops(struct uart_port *port)
1779 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1781 if (atmel_use_dma_rx(port)) {
1782 atmel_port->prepare_rx = &atmel_prepare_rx_dma;
1783 atmel_port->schedule_rx = &atmel_rx_from_dma;
1784 atmel_port->release_rx = &atmel_release_rx_dma;
1785 } else if (atmel_use_pdc_rx(port)) {
1786 atmel_port->prepare_rx = &atmel_prepare_rx_pdc;
1787 atmel_port->schedule_rx = &atmel_rx_from_pdc;
1788 atmel_port->release_rx = &atmel_release_rx_pdc;
1790 atmel_port->prepare_rx = NULL;
1791 atmel_port->schedule_rx = &atmel_rx_from_ring;
1792 atmel_port->release_rx = NULL;
1795 if (atmel_use_dma_tx(port)) {
1796 atmel_port->prepare_tx = &atmel_prepare_tx_dma;
1797 atmel_port->schedule_tx = &atmel_tx_dma;
1798 atmel_port->release_tx = &atmel_release_tx_dma;
1799 } else if (atmel_use_pdc_tx(port)) {
1800 atmel_port->prepare_tx = &atmel_prepare_tx_pdc;
1801 atmel_port->schedule_tx = &atmel_tx_pdc;
1802 atmel_port->release_tx = &atmel_release_tx_pdc;
1804 atmel_port->prepare_tx = NULL;
1805 atmel_port->schedule_tx = &atmel_tx_chars;
1806 atmel_port->release_tx = NULL;
1811 * Get ip name usart or uart
1813 static void atmel_get_ip_name(struct uart_port *port)
1815 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1816 int name = atmel_uart_readl(port, ATMEL_US_NAME);
1818 u32 usart, dbgu_uart, new_uart;
1819 /* ASCII decoding for IP version */
1820 usart = 0x55534152; /* USAR(T) */
1821 dbgu_uart = 0x44424755; /* DBGU */
1822 new_uart = 0x55415254; /* UART */
1825 * Only USART devices from at91sam9260 SOC implement fractional
1826 * baudrate. It is available for all asynchronous modes, with the
1827 * following restriction: the sampling clock's duty cycle is not
1830 atmel_port->has_frac_baudrate = false;
1831 atmel_port->has_hw_timer = false;
1833 if (name == new_uart) {
1834 dev_dbg(port->dev, "Uart with hw timer");
1835 atmel_port->has_hw_timer = true;
1836 atmel_port->rtor = ATMEL_UA_RTOR;
1837 } else if (name == usart) {
1838 dev_dbg(port->dev, "Usart\n");
1839 atmel_port->has_frac_baudrate = true;
1840 atmel_port->has_hw_timer = true;
1841 atmel_port->rtor = ATMEL_US_RTOR;
1842 version = atmel_uart_readl(port, ATMEL_US_VERSION);
1844 case 0x814: /* sama5d2 */
1846 case 0x701: /* sama5d4 */
1847 atmel_port->fidi_min = 3;
1848 atmel_port->fidi_max = 65535;
1850 case 0x502: /* sam9x5, sama5d3 */
1851 atmel_port->fidi_min = 3;
1852 atmel_port->fidi_max = 2047;
1855 atmel_port->fidi_min = 1;
1856 atmel_port->fidi_max = 2047;
1858 } else if (name == dbgu_uart) {
1859 dev_dbg(port->dev, "Dbgu or uart without hw timer\n");
1861 /* fallback for older SoCs: use version field */
1862 version = atmel_uart_readl(port, ATMEL_US_VERSION);
1867 dev_dbg(port->dev, "This version is usart\n");
1868 atmel_port->has_frac_baudrate = true;
1869 atmel_port->has_hw_timer = true;
1870 atmel_port->rtor = ATMEL_US_RTOR;
1874 dev_dbg(port->dev, "This version is uart\n");
1877 dev_err(port->dev, "Not supported ip name nor version, set to uart\n");
1883 * Perform initialization and enable port for reception
1885 static int atmel_startup(struct uart_port *port)
1887 struct platform_device *pdev = to_platform_device(port->dev);
1888 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1892 * Ensure that no interrupts are enabled otherwise when
1893 * request_irq() is called we could get stuck trying to
1894 * handle an unexpected interrupt
1896 atmel_uart_writel(port, ATMEL_US_IDR, -1);
1897 atmel_port->ms_irq_enabled = false;
1902 retval = request_irq(port->irq, atmel_interrupt,
1903 IRQF_SHARED | IRQF_COND_SUSPEND,
1904 dev_name(&pdev->dev), port);
1906 dev_err(port->dev, "atmel_startup - Can't get irq\n");
1910 atomic_set(&atmel_port->tasklet_shutdown, 0);
1911 tasklet_init(&atmel_port->tasklet_rx, atmel_tasklet_rx_func,
1912 (unsigned long)port);
1913 tasklet_init(&atmel_port->tasklet_tx, atmel_tasklet_tx_func,
1914 (unsigned long)port);
1917 * Initialize DMA (if necessary)
1919 atmel_init_property(atmel_port, pdev);
1920 atmel_set_ops(port);
1922 if (atmel_port->prepare_rx) {
1923 retval = atmel_port->prepare_rx(port);
1925 atmel_set_ops(port);
1928 if (atmel_port->prepare_tx) {
1929 retval = atmel_port->prepare_tx(port);
1931 atmel_set_ops(port);
1935 * Enable FIFO when available
1937 if (atmel_port->fifo_size) {
1938 unsigned int txrdym = ATMEL_US_ONE_DATA;
1939 unsigned int rxrdym = ATMEL_US_ONE_DATA;
1942 atmel_uart_writel(port, ATMEL_US_CR,
1947 if (atmel_use_dma_tx(port))
1948 txrdym = ATMEL_US_FOUR_DATA;
1950 fmr = ATMEL_US_TXRDYM(txrdym) | ATMEL_US_RXRDYM(rxrdym);
1951 if (atmel_port->rts_high &&
1952 atmel_port->rts_low)
1953 fmr |= ATMEL_US_FRTSC |
1954 ATMEL_US_RXFTHRES(atmel_port->rts_high) |
1955 ATMEL_US_RXFTHRES2(atmel_port->rts_low);
1957 atmel_uart_writel(port, ATMEL_US_FMR, fmr);
1960 /* Save current CSR for comparison in atmel_tasklet_func() */
1961 atmel_port->irq_status_prev = atmel_uart_readl(port, ATMEL_US_CSR);
1964 * Finally, enable the serial port
1966 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
1967 /* enable xmit & rcvr */
1968 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN);
1969 atmel_port->tx_stopped = false;
1971 timer_setup(&atmel_port->uart_timer, atmel_uart_timer_callback, 0);
1973 if (atmel_use_pdc_rx(port)) {
1974 /* set UART timeout */
1975 if (!atmel_port->has_hw_timer) {
1976 mod_timer(&atmel_port->uart_timer,
1977 jiffies + uart_poll_timeout(port));
1978 /* set USART timeout */
1980 atmel_uart_writel(port, atmel_port->rtor,
1982 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STTTO);
1984 atmel_uart_writel(port, ATMEL_US_IER,
1985 ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);
1987 /* enable PDC controller */
1988 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_RXTEN);
1989 } else if (atmel_use_dma_rx(port)) {
1990 /* set UART timeout */
1991 if (!atmel_port->has_hw_timer) {
1992 mod_timer(&atmel_port->uart_timer,
1993 jiffies + uart_poll_timeout(port));
1994 /* set USART timeout */
1996 atmel_uart_writel(port, atmel_port->rtor,
1998 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STTTO);
2000 atmel_uart_writel(port, ATMEL_US_IER,
2004 /* enable receive only */
2005 atmel_uart_writel(port, ATMEL_US_IER, ATMEL_US_RXRDY);
2012 * Flush any TX data submitted for DMA. Called when the TX circular
2015 static void atmel_flush_buffer(struct uart_port *port)
2017 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2019 if (atmel_use_pdc_tx(port)) {
2020 atmel_uart_writel(port, ATMEL_PDC_TCR, 0);
2021 atmel_port->pdc_tx.ofs = 0;
2024 * in uart_flush_buffer(), the xmit circular buffer has just
2025 * been cleared, so we have to reset tx_len accordingly.
2027 atmel_port->tx_len = 0;
2033 static void atmel_shutdown(struct uart_port *port)
2035 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2037 /* Disable modem control lines interrupts */
2038 atmel_disable_ms(port);
2040 /* Disable interrupts at device level */
2041 atmel_uart_writel(port, ATMEL_US_IDR, -1);
2043 /* Prevent spurious interrupts from scheduling the tasklet */
2044 atomic_inc(&atmel_port->tasklet_shutdown);
2047 * Prevent any tasklets being scheduled during
2050 del_timer_sync(&atmel_port->uart_timer);
2052 /* Make sure that no interrupt is on the fly */
2053 synchronize_irq(port->irq);
2056 * Clear out any scheduled tasklets before
2057 * we destroy the buffers
2059 tasklet_kill(&atmel_port->tasklet_rx);
2060 tasklet_kill(&atmel_port->tasklet_tx);
2063 * Ensure everything is stopped and
2064 * disable port and break condition.
2066 atmel_stop_rx(port);
2067 atmel_stop_tx(port);
2069 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA);
2072 * Shut-down the DMA.
2074 if (atmel_port->release_rx)
2075 atmel_port->release_rx(port);
2076 if (atmel_port->release_tx)
2077 atmel_port->release_tx(port);
2080 * Reset ring buffer pointers
2082 atmel_port->rx_ring.head = 0;
2083 atmel_port->rx_ring.tail = 0;
2086 * Free the interrupts
2088 free_irq(port->irq, port);
2090 atmel_flush_buffer(port);
2094 * Power / Clock management.
2096 static void atmel_serial_pm(struct uart_port *port, unsigned int state,
2097 unsigned int oldstate)
2099 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2104 * Enable the peripheral clock for this serial port.
2105 * This is called on uart_open() or a resume event.
2107 clk_prepare_enable(atmel_port->clk);
2109 /* re-enable interrupts if we disabled some on suspend */
2110 atmel_uart_writel(port, ATMEL_US_IER, atmel_port->backup_imr);
2113 /* Back up the interrupt mask and disable all interrupts */
2114 atmel_port->backup_imr = atmel_uart_readl(port, ATMEL_US_IMR);
2115 atmel_uart_writel(port, ATMEL_US_IDR, -1);
2118 * Disable the peripheral clock for this serial port.
2119 * This is called on uart_close() or a suspend event.
2121 clk_disable_unprepare(atmel_port->clk);
2124 dev_err(port->dev, "atmel_serial: unknown pm %d\n", state);
2129 * Change the port parameters
2131 static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
2132 struct ktermios *old)
2134 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2135 unsigned long flags;
2136 unsigned int old_mode, mode, imr, quot, baud, div, cd, fp = 0;
2138 /* save the current mode register */
2139 mode = old_mode = atmel_uart_readl(port, ATMEL_US_MR);
2141 /* reset the mode, clock divisor, parity, stop bits and data size */
2142 mode &= ~(ATMEL_US_USCLKS | ATMEL_US_CHRL | ATMEL_US_NBSTOP |
2143 ATMEL_US_PAR | ATMEL_US_USMODE);
2145 baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
2148 switch (termios->c_cflag & CSIZE) {
2150 mode |= ATMEL_US_CHRL_5;
2153 mode |= ATMEL_US_CHRL_6;
2156 mode |= ATMEL_US_CHRL_7;
2159 mode |= ATMEL_US_CHRL_8;
2164 if (termios->c_cflag & CSTOPB)
2165 mode |= ATMEL_US_NBSTOP_2;
2168 if (termios->c_cflag & PARENB) {
2169 /* Mark or Space parity */
2170 if (termios->c_cflag & CMSPAR) {
2171 if (termios->c_cflag & PARODD)
2172 mode |= ATMEL_US_PAR_MARK;
2174 mode |= ATMEL_US_PAR_SPACE;
2175 } else if (termios->c_cflag & PARODD)
2176 mode |= ATMEL_US_PAR_ODD;
2178 mode |= ATMEL_US_PAR_EVEN;
2180 mode |= ATMEL_US_PAR_NONE;
2182 spin_lock_irqsave(&port->lock, flags);
2184 port->read_status_mask = ATMEL_US_OVRE;
2185 if (termios->c_iflag & INPCK)
2186 port->read_status_mask |= (ATMEL_US_FRAME | ATMEL_US_PARE);
2187 if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
2188 port->read_status_mask |= ATMEL_US_RXBRK;
2190 if (atmel_use_pdc_rx(port))
2191 /* need to enable error interrupts */
2192 atmel_uart_writel(port, ATMEL_US_IER, port->read_status_mask);
2195 * Characters to ignore
2197 port->ignore_status_mask = 0;
2198 if (termios->c_iflag & IGNPAR)
2199 port->ignore_status_mask |= (ATMEL_US_FRAME | ATMEL_US_PARE);
2200 if (termios->c_iflag & IGNBRK) {
2201 port->ignore_status_mask |= ATMEL_US_RXBRK;
2203 * If we're ignoring parity and break indicators,
2204 * ignore overruns too (for real raw support).
2206 if (termios->c_iflag & IGNPAR)
2207 port->ignore_status_mask |= ATMEL_US_OVRE;
2209 /* TODO: Ignore all characters if CREAD is set.*/
2211 /* update the per-port timeout */
2212 uart_update_timeout(port, termios->c_cflag, baud);
2215 * save/disable interrupts. The tty layer will ensure that the
2216 * transmitter is empty if requested by the caller, so there's
2217 * no need to wait for it here.
2219 imr = atmel_uart_readl(port, ATMEL_US_IMR);
2220 atmel_uart_writel(port, ATMEL_US_IDR, -1);
2222 /* disable receiver and transmitter */
2223 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXDIS | ATMEL_US_RXDIS);
2224 atmel_port->tx_stopped = true;
2227 if (port->rs485.flags & SER_RS485_ENABLED) {
2228 atmel_uart_writel(port, ATMEL_US_TTGR,
2229 port->rs485.delay_rts_after_send);
2230 mode |= ATMEL_US_USMODE_RS485;
2231 } else if (port->iso7816.flags & SER_ISO7816_ENABLED) {
2232 atmel_uart_writel(port, ATMEL_US_TTGR, port->iso7816.tg);
2233 /* select mck clock, and output */
2234 mode |= ATMEL_US_USCLKS_MCK | ATMEL_US_CLKO;
2235 /* set max iterations */
2236 mode |= ATMEL_US_MAX_ITER(3);
2237 if ((port->iso7816.flags & SER_ISO7816_T_PARAM)
2238 == SER_ISO7816_T(0))
2239 mode |= ATMEL_US_USMODE_ISO7816_T0;
2241 mode |= ATMEL_US_USMODE_ISO7816_T1;
2242 } else if (termios->c_cflag & CRTSCTS) {
2243 /* RS232 with hardware handshake (RTS/CTS) */
2244 if (atmel_use_fifo(port) &&
2245 !mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS)) {
2247 * with ATMEL_US_USMODE_HWHS set, the controller will
2248 * be able to drive the RTS pin high/low when the RX
2249 * FIFO is above RXFTHRES/below RXFTHRES2.
2250 * It will also disable the transmitter when the CTS
2252 * This mode is not activated if CTS pin is a GPIO
2253 * because in this case, the transmitter is always
2254 * disabled (there must be an internal pull-up
2255 * responsible for this behaviour).
2256 * If the RTS pin is a GPIO, the controller won't be
2257 * able to drive it according to the FIFO thresholds,
2258 * but it will be handled by the driver.
2260 mode |= ATMEL_US_USMODE_HWHS;
2263 * For platforms without FIFO, the flow control is
2264 * handled by the driver.
2266 mode |= ATMEL_US_USMODE_NORMAL;
2269 /* RS232 without hadware handshake */
2270 mode |= ATMEL_US_USMODE_NORMAL;
2274 * Set the baud rate:
2275 * Fractional baudrate allows to setup output frequency more
2276 * accurately. This feature is enabled only when using normal mode.
2277 * baudrate = selected clock / (8 * (2 - OVER) * (CD + FP / 8))
2278 * Currently, OVER is always set to 0 so we get
2279 * baudrate = selected clock / (16 * (CD + FP / 8))
2281 * 8 CD + FP = selected clock / (2 * baudrate)
2283 if (atmel_port->has_frac_baudrate) {
2284 div = DIV_ROUND_CLOSEST(port->uartclk, baud * 2);
2286 fp = div & ATMEL_US_FP_MASK;
2288 cd = uart_get_divisor(port, baud);
2291 if (cd > 65535) { /* BRGR is 16-bit, so switch to slower clock */
2293 mode |= ATMEL_US_USCLKS_MCK_DIV8;
2295 quot = cd | fp << ATMEL_US_FP_OFFSET;
2297 if (!(port->iso7816.flags & SER_ISO7816_ENABLED))
2298 atmel_uart_writel(port, ATMEL_US_BRGR, quot);
2300 /* set the mode, clock divisor, parity, stop bits and data size */
2301 atmel_uart_writel(port, ATMEL_US_MR, mode);
2304 * when switching the mode, set the RTS line state according to the
2305 * new mode, otherwise keep the former state
2307 if ((old_mode & ATMEL_US_USMODE) != (mode & ATMEL_US_USMODE)) {
2308 unsigned int rts_state;
2310 if ((mode & ATMEL_US_USMODE) == ATMEL_US_USMODE_HWHS) {
2311 /* let the hardware control the RTS line */
2312 rts_state = ATMEL_US_RTSDIS;
2314 /* force RTS line to low level */
2315 rts_state = ATMEL_US_RTSEN;
2318 atmel_uart_writel(port, ATMEL_US_CR, rts_state);
2321 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
2322 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN);
2323 atmel_port->tx_stopped = false;
2325 /* restore interrupts */
2326 atmel_uart_writel(port, ATMEL_US_IER, imr);
2328 /* CTS flow-control and modem-status interrupts */
2329 if (UART_ENABLE_MS(port, termios->c_cflag))
2330 atmel_enable_ms(port);
2332 atmel_disable_ms(port);
2334 spin_unlock_irqrestore(&port->lock, flags);
2337 static void atmel_set_ldisc(struct uart_port *port, struct ktermios *termios)
2339 if (termios->c_line == N_PPS) {
2340 port->flags |= UPF_HARDPPS_CD;
2341 spin_lock_irq(&port->lock);
2342 atmel_enable_ms(port);
2343 spin_unlock_irq(&port->lock);
2345 port->flags &= ~UPF_HARDPPS_CD;
2346 if (!UART_ENABLE_MS(port, termios->c_cflag)) {
2347 spin_lock_irq(&port->lock);
2348 atmel_disable_ms(port);
2349 spin_unlock_irq(&port->lock);
2355 * Return string describing the specified port
2357 static const char *atmel_type(struct uart_port *port)
2359 return (port->type == PORT_ATMEL) ? "ATMEL_SERIAL" : NULL;
2363 * Release the memory region(s) being used by 'port'.
2365 static void atmel_release_port(struct uart_port *port)
2367 struct platform_device *mpdev = to_platform_device(port->dev->parent);
2368 int size = resource_size(mpdev->resource);
2370 release_mem_region(port->mapbase, size);
2372 if (port->flags & UPF_IOREMAP) {
2373 iounmap(port->membase);
2374 port->membase = NULL;
2379 * Request the memory region(s) being used by 'port'.
2381 static int atmel_request_port(struct uart_port *port)
2383 struct platform_device *mpdev = to_platform_device(port->dev->parent);
2384 int size = resource_size(mpdev->resource);
2386 if (!request_mem_region(port->mapbase, size, "atmel_serial"))
2389 if (port->flags & UPF_IOREMAP) {
2390 port->membase = ioremap(port->mapbase, size);
2391 if (port->membase == NULL) {
2392 release_mem_region(port->mapbase, size);
2401 * Configure/autoconfigure the port.
2403 static void atmel_config_port(struct uart_port *port, int flags)
2405 if (flags & UART_CONFIG_TYPE) {
2406 port->type = PORT_ATMEL;
2407 atmel_request_port(port);
2412 * Verify the new serial_struct (for TIOCSSERIAL).
2414 static int atmel_verify_port(struct uart_port *port, struct serial_struct *ser)
2417 if (ser->type != PORT_UNKNOWN && ser->type != PORT_ATMEL)
2419 if (port->irq != ser->irq)
2421 if (ser->io_type != SERIAL_IO_MEM)
2423 if (port->uartclk / 16 != ser->baud_base)
2425 if (port->mapbase != (unsigned long)ser->iomem_base)
2427 if (port->iobase != ser->port)
2434 #ifdef CONFIG_CONSOLE_POLL
2435 static int atmel_poll_get_char(struct uart_port *port)
2437 while (!(atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_RXRDY))
2440 return atmel_uart_read_char(port);
2443 static void atmel_poll_put_char(struct uart_port *port, unsigned char ch)
2445 while (!(atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXRDY))
2448 atmel_uart_write_char(port, ch);
2452 static const struct uart_ops atmel_pops = {
2453 .tx_empty = atmel_tx_empty,
2454 .set_mctrl = atmel_set_mctrl,
2455 .get_mctrl = atmel_get_mctrl,
2456 .stop_tx = atmel_stop_tx,
2457 .start_tx = atmel_start_tx,
2458 .stop_rx = atmel_stop_rx,
2459 .enable_ms = atmel_enable_ms,
2460 .break_ctl = atmel_break_ctl,
2461 .startup = atmel_startup,
2462 .shutdown = atmel_shutdown,
2463 .flush_buffer = atmel_flush_buffer,
2464 .set_termios = atmel_set_termios,
2465 .set_ldisc = atmel_set_ldisc,
2467 .release_port = atmel_release_port,
2468 .request_port = atmel_request_port,
2469 .config_port = atmel_config_port,
2470 .verify_port = atmel_verify_port,
2471 .pm = atmel_serial_pm,
2472 #ifdef CONFIG_CONSOLE_POLL
2473 .poll_get_char = atmel_poll_get_char,
2474 .poll_put_char = atmel_poll_put_char,
2479 * Configure the port from the platform device resource info.
2481 static int atmel_init_port(struct atmel_uart_port *atmel_port,
2482 struct platform_device *pdev)
2485 struct uart_port *port = &atmel_port->uart;
2486 struct platform_device *mpdev = to_platform_device(pdev->dev.parent);
2488 atmel_init_property(atmel_port, pdev);
2489 atmel_set_ops(port);
2491 uart_get_rs485_mode(&mpdev->dev, &port->rs485);
2493 port->iotype = UPIO_MEM;
2494 port->flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP;
2495 port->ops = &atmel_pops;
2497 port->dev = &pdev->dev;
2498 port->mapbase = mpdev->resource[0].start;
2499 port->irq = mpdev->resource[1].start;
2500 port->rs485_config = atmel_config_rs485;
2501 port->iso7816_config = atmel_config_iso7816;
2502 port->membase = NULL;
2504 memset(&atmel_port->rx_ring, 0, sizeof(atmel_port->rx_ring));
2506 /* for console, the clock could already be configured */
2507 if (!atmel_port->clk) {
2508 atmel_port->clk = clk_get(&mpdev->dev, "usart");
2509 if (IS_ERR(atmel_port->clk)) {
2510 ret = PTR_ERR(atmel_port->clk);
2511 atmel_port->clk = NULL;
2514 ret = clk_prepare_enable(atmel_port->clk);
2516 clk_put(atmel_port->clk);
2517 atmel_port->clk = NULL;
2520 port->uartclk = clk_get_rate(atmel_port->clk);
2521 clk_disable_unprepare(atmel_port->clk);
2522 /* only enable clock when USART is in use */
2526 * Use TXEMPTY for interrupt when rs485 or ISO7816 else TXRDY or
2529 if (port->rs485.flags & SER_RS485_ENABLED ||
2530 port->iso7816.flags & SER_ISO7816_ENABLED)
2531 atmel_port->tx_done_mask = ATMEL_US_TXEMPTY;
2532 else if (atmel_use_pdc_tx(port)) {
2533 port->fifosize = PDC_BUFFER_SIZE;
2534 atmel_port->tx_done_mask = ATMEL_US_ENDTX | ATMEL_US_TXBUFE;
2536 atmel_port->tx_done_mask = ATMEL_US_TXRDY;
2542 #ifdef CONFIG_SERIAL_ATMEL_CONSOLE
2543 static void atmel_console_putchar(struct uart_port *port, int ch)
2545 while (!(atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXRDY))
2547 atmel_uart_write_char(port, ch);
2551 * Interrupts are disabled on entering
2553 static void atmel_console_write(struct console *co, const char *s, u_int count)
2555 struct uart_port *port = &atmel_ports[co->index].uart;
2556 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2557 unsigned int status, imr;
2558 unsigned int pdc_tx;
2561 * First, save IMR and then disable interrupts
2563 imr = atmel_uart_readl(port, ATMEL_US_IMR);
2564 atmel_uart_writel(port, ATMEL_US_IDR,
2565 ATMEL_US_RXRDY | atmel_port->tx_done_mask);
2567 /* Store PDC transmit status and disable it */
2568 pdc_tx = atmel_uart_readl(port, ATMEL_PDC_PTSR) & ATMEL_PDC_TXTEN;
2569 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTDIS);
2571 /* Make sure that tx path is actually able to send characters */
2572 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN);
2573 atmel_port->tx_stopped = false;
2575 uart_console_write(port, s, count, atmel_console_putchar);
2578 * Finally, wait for transmitter to become empty
2582 status = atmel_uart_readl(port, ATMEL_US_CSR);
2583 } while (!(status & ATMEL_US_TXRDY));
2585 /* Restore PDC transmit status */
2587 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTEN);
2589 /* set interrupts back the way they were */
2590 atmel_uart_writel(port, ATMEL_US_IER, imr);
2594 * If the port was already initialised (eg, by a boot loader),
2595 * try to determine the current setup.
2597 static void __init atmel_console_get_options(struct uart_port *port, int *baud,
2598 int *parity, int *bits)
2600 unsigned int mr, quot;
2603 * If the baud rate generator isn't running, the port wasn't
2604 * initialized by the boot loader.
2606 quot = atmel_uart_readl(port, ATMEL_US_BRGR) & ATMEL_US_CD;
2610 mr = atmel_uart_readl(port, ATMEL_US_MR) & ATMEL_US_CHRL;
2611 if (mr == ATMEL_US_CHRL_8)
2616 mr = atmel_uart_readl(port, ATMEL_US_MR) & ATMEL_US_PAR;
2617 if (mr == ATMEL_US_PAR_EVEN)
2619 else if (mr == ATMEL_US_PAR_ODD)
2623 * The serial core only rounds down when matching this to a
2624 * supported baud rate. Make sure we don't end up slightly
2625 * lower than one of those, as it would make us fall through
2626 * to a much lower baud rate than we really want.
2628 *baud = port->uartclk / (16 * (quot - 1));
2631 static int __init atmel_console_setup(struct console *co, char *options)
2634 struct uart_port *port = &atmel_ports[co->index].uart;
2635 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2641 if (port->membase == NULL) {
2642 /* Port not initialized yet - delay setup */
2646 ret = clk_prepare_enable(atmel_ports[co->index].clk);
2650 atmel_uart_writel(port, ATMEL_US_IDR, -1);
2651 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
2652 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN);
2653 atmel_port->tx_stopped = false;
2656 uart_parse_options(options, &baud, &parity, &bits, &flow);
2658 atmel_console_get_options(port, &baud, &parity, &bits);
2660 return uart_set_options(port, co, baud, parity, bits, flow);
2663 static struct uart_driver atmel_uart;
2665 static struct console atmel_console = {
2666 .name = ATMEL_DEVICENAME,
2667 .write = atmel_console_write,
2668 .device = uart_console_device,
2669 .setup = atmel_console_setup,
2670 .flags = CON_PRINTBUFFER,
2672 .data = &atmel_uart,
2675 #define ATMEL_CONSOLE_DEVICE (&atmel_console)
2677 static inline bool atmel_is_console_port(struct uart_port *port)
2679 return port->cons && port->cons->index == port->line;
2683 #define ATMEL_CONSOLE_DEVICE NULL
2685 static inline bool atmel_is_console_port(struct uart_port *port)
2691 static struct uart_driver atmel_uart = {
2692 .owner = THIS_MODULE,
2693 .driver_name = "atmel_serial",
2694 .dev_name = ATMEL_DEVICENAME,
2695 .major = SERIAL_ATMEL_MAJOR,
2696 .minor = MINOR_START,
2697 .nr = ATMEL_MAX_UART,
2698 .cons = ATMEL_CONSOLE_DEVICE,
2702 static bool atmel_serial_clk_will_stop(void)
2704 #ifdef CONFIG_ARCH_AT91
2705 return at91_suspend_entering_slow_clock();
2711 static int atmel_serial_suspend(struct platform_device *pdev,
2714 struct uart_port *port = platform_get_drvdata(pdev);
2715 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2717 if (atmel_is_console_port(port) && console_suspend_enabled) {
2718 /* Drain the TX shifter */
2719 while (!(atmel_uart_readl(port, ATMEL_US_CSR) &
2724 if (atmel_is_console_port(port) && !console_suspend_enabled) {
2725 /* Cache register values as we won't get a full shutdown/startup
2728 atmel_port->cache.mr = atmel_uart_readl(port, ATMEL_US_MR);
2729 atmel_port->cache.imr = atmel_uart_readl(port, ATMEL_US_IMR);
2730 atmel_port->cache.brgr = atmel_uart_readl(port, ATMEL_US_BRGR);
2731 atmel_port->cache.rtor = atmel_uart_readl(port,
2733 atmel_port->cache.ttgr = atmel_uart_readl(port, ATMEL_US_TTGR);
2734 atmel_port->cache.fmr = atmel_uart_readl(port, ATMEL_US_FMR);
2735 atmel_port->cache.fimr = atmel_uart_readl(port, ATMEL_US_FIMR);
2738 /* we can not wake up if we're running on slow clock */
2739 atmel_port->may_wakeup = device_may_wakeup(&pdev->dev);
2740 if (atmel_serial_clk_will_stop()) {
2741 unsigned long flags;
2743 spin_lock_irqsave(&atmel_port->lock_suspended, flags);
2744 atmel_port->suspended = true;
2745 spin_unlock_irqrestore(&atmel_port->lock_suspended, flags);
2746 device_set_wakeup_enable(&pdev->dev, 0);
2749 uart_suspend_port(&atmel_uart, port);
2754 static int atmel_serial_resume(struct platform_device *pdev)
2756 struct uart_port *port = platform_get_drvdata(pdev);
2757 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2758 unsigned long flags;
2760 if (atmel_is_console_port(port) && !console_suspend_enabled) {
2761 atmel_uart_writel(port, ATMEL_US_MR, atmel_port->cache.mr);
2762 atmel_uart_writel(port, ATMEL_US_IER, atmel_port->cache.imr);
2763 atmel_uart_writel(port, ATMEL_US_BRGR, atmel_port->cache.brgr);
2764 atmel_uart_writel(port, atmel_port->rtor,
2765 atmel_port->cache.rtor);
2766 atmel_uart_writel(port, ATMEL_US_TTGR, atmel_port->cache.ttgr);
2768 if (atmel_port->fifo_size) {
2769 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_FIFOEN |
2770 ATMEL_US_RXFCLR | ATMEL_US_TXFLCLR);
2771 atmel_uart_writel(port, ATMEL_US_FMR,
2772 atmel_port->cache.fmr);
2773 atmel_uart_writel(port, ATMEL_US_FIER,
2774 atmel_port->cache.fimr);
2776 atmel_start_rx(port);
2779 spin_lock_irqsave(&atmel_port->lock_suspended, flags);
2780 if (atmel_port->pending) {
2781 atmel_handle_receive(port, atmel_port->pending);
2782 atmel_handle_status(port, atmel_port->pending,
2783 atmel_port->pending_status);
2784 atmel_handle_transmit(port, atmel_port->pending);
2785 atmel_port->pending = 0;
2787 atmel_port->suspended = false;
2788 spin_unlock_irqrestore(&atmel_port->lock_suspended, flags);
2790 uart_resume_port(&atmel_uart, port);
2791 device_set_wakeup_enable(&pdev->dev, atmel_port->may_wakeup);
2796 #define atmel_serial_suspend NULL
2797 #define atmel_serial_resume NULL
2800 static void atmel_serial_probe_fifos(struct atmel_uart_port *atmel_port,
2801 struct platform_device *pdev)
2803 atmel_port->fifo_size = 0;
2804 atmel_port->rts_low = 0;
2805 atmel_port->rts_high = 0;
2807 if (of_property_read_u32(pdev->dev.of_node,
2809 &atmel_port->fifo_size))
2812 if (!atmel_port->fifo_size)
2815 if (atmel_port->fifo_size < ATMEL_MIN_FIFO_SIZE) {
2816 atmel_port->fifo_size = 0;
2817 dev_err(&pdev->dev, "Invalid FIFO size\n");
2822 * 0 <= rts_low <= rts_high <= fifo_size
2823 * Once their CTS line asserted by the remote peer, some x86 UARTs tend
2824 * to flush their internal TX FIFO, commonly up to 16 data, before
2825 * actually stopping to send new data. So we try to set the RTS High
2826 * Threshold to a reasonably high value respecting this 16 data
2827 * empirical rule when possible.
2829 atmel_port->rts_high = max_t(int, atmel_port->fifo_size >> 1,
2830 atmel_port->fifo_size - ATMEL_RTS_HIGH_OFFSET);
2831 atmel_port->rts_low = max_t(int, atmel_port->fifo_size >> 2,
2832 atmel_port->fifo_size - ATMEL_RTS_LOW_OFFSET);
2834 dev_info(&pdev->dev, "Using FIFO (%u data)\n",
2835 atmel_port->fifo_size);
2836 dev_dbg(&pdev->dev, "RTS High Threshold : %2u data\n",
2837 atmel_port->rts_high);
2838 dev_dbg(&pdev->dev, "RTS Low Threshold : %2u data\n",
2839 atmel_port->rts_low);
2842 static int atmel_serial_probe(struct platform_device *pdev)
2844 struct atmel_uart_port *atmel_port;
2845 struct device_node *np = pdev->dev.parent->of_node;
2850 BUILD_BUG_ON(ATMEL_SERIAL_RINGSIZE & (ATMEL_SERIAL_RINGSIZE - 1));
2853 * In device tree there is no node with "atmel,at91rm9200-usart-serial"
2854 * as compatible string. This driver is probed by at91-usart mfd driver
2855 * which is just a wrapper over the atmel_serial driver and
2856 * spi-at91-usart driver. All attributes needed by this driver are
2857 * found in of_node of parent.
2859 pdev->dev.of_node = np;
2861 ret = of_alias_get_id(np, "serial");
2863 /* port id not found in platform data nor device-tree aliases:
2864 * auto-enumerate it */
2865 ret = find_first_zero_bit(atmel_ports_in_use, ATMEL_MAX_UART);
2867 if (ret >= ATMEL_MAX_UART) {
2872 if (test_and_set_bit(ret, atmel_ports_in_use)) {
2873 /* port already in use */
2878 atmel_port = &atmel_ports[ret];
2879 atmel_port->backup_imr = 0;
2880 atmel_port->uart.line = ret;
2881 atmel_serial_probe_fifos(atmel_port, pdev);
2883 atomic_set(&atmel_port->tasklet_shutdown, 0);
2884 spin_lock_init(&atmel_port->lock_suspended);
2886 ret = atmel_init_port(atmel_port, pdev);
2890 atmel_port->gpios = mctrl_gpio_init(&atmel_port->uart, 0);
2891 if (IS_ERR(atmel_port->gpios)) {
2892 ret = PTR_ERR(atmel_port->gpios);
2896 if (!atmel_use_pdc_rx(&atmel_port->uart)) {
2898 data = kmalloc_array(ATMEL_SERIAL_RINGSIZE,
2899 sizeof(struct atmel_uart_char),
2902 goto err_alloc_ring;
2903 atmel_port->rx_ring.buf = data;
2906 rs485_enabled = atmel_port->uart.rs485.flags & SER_RS485_ENABLED;
2908 ret = uart_add_one_port(&atmel_uart, &atmel_port->uart);
2912 #ifdef CONFIG_SERIAL_ATMEL_CONSOLE
2913 if (atmel_is_console_port(&atmel_port->uart)
2914 && ATMEL_CONSOLE_DEVICE->flags & CON_ENABLED) {
2916 * The serial core enabled the clock for us, so undo
2917 * the clk_prepare_enable() in atmel_console_setup()
2919 clk_disable_unprepare(atmel_port->clk);
2923 device_init_wakeup(&pdev->dev, 1);
2924 platform_set_drvdata(pdev, atmel_port);
2927 * The peripheral clock has been disabled by atmel_init_port():
2928 * enable it before accessing I/O registers
2930 clk_prepare_enable(atmel_port->clk);
2932 if (rs485_enabled) {
2933 atmel_uart_writel(&atmel_port->uart, ATMEL_US_MR,
2934 ATMEL_US_USMODE_NORMAL);
2935 atmel_uart_writel(&atmel_port->uart, ATMEL_US_CR,
2940 * Get port name of usart or uart
2942 atmel_get_ip_name(&atmel_port->uart);
2945 * The peripheral clock can now safely be disabled till the port
2948 clk_disable_unprepare(atmel_port->clk);
2953 kfree(atmel_port->rx_ring.buf);
2954 atmel_port->rx_ring.buf = NULL;
2956 if (!atmel_is_console_port(&atmel_port->uart)) {
2957 clk_put(atmel_port->clk);
2958 atmel_port->clk = NULL;
2961 clear_bit(atmel_port->uart.line, atmel_ports_in_use);
2967 * Even if the driver is not modular, it makes sense to be able to
2968 * unbind a device: there can be many bound devices, and there are
2969 * situations where dynamic binding and unbinding can be useful.
2971 * For example, a connected device can require a specific firmware update
2972 * protocol that needs bitbanging on IO lines, but use the regular serial
2973 * port in the normal case.
2975 static int atmel_serial_remove(struct platform_device *pdev)
2977 struct uart_port *port = platform_get_drvdata(pdev);
2978 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2981 tasklet_kill(&atmel_port->tasklet_rx);
2982 tasklet_kill(&atmel_port->tasklet_tx);
2984 device_init_wakeup(&pdev->dev, 0);
2986 ret = uart_remove_one_port(&atmel_uart, port);
2988 kfree(atmel_port->rx_ring.buf);
2990 /* "port" is allocated statically, so we shouldn't free it */
2992 clear_bit(port->line, atmel_ports_in_use);
2994 clk_put(atmel_port->clk);
2995 atmel_port->clk = NULL;
2996 pdev->dev.of_node = NULL;
3001 static struct platform_driver atmel_serial_driver = {
3002 .probe = atmel_serial_probe,
3003 .remove = atmel_serial_remove,
3004 .suspend = atmel_serial_suspend,
3005 .resume = atmel_serial_resume,
3007 .name = "atmel_usart_serial",
3008 .of_match_table = of_match_ptr(atmel_serial_dt_ids),
3012 static int __init atmel_serial_init(void)
3016 ret = uart_register_driver(&atmel_uart);
3020 ret = platform_driver_register(&atmel_serial_driver);
3022 uart_unregister_driver(&atmel_uart);
3026 device_initcall(atmel_serial_init);