1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Driver for Atmel AT91 Serial ports
4 * Copyright (C) 2003 Rick Bronson
5 *
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.
8 *
9 * DMA support added by Chip Coldwell.
10 */
11 #include <linux/circ_buf.h>
12 #include <linux/tty.h>
13 #include <linux/ioport.h>
14 #include <linux/slab.h>
15 #include <linux/init.h>
16 #include <linux/serial.h>
17 #include <linux/clk.h>
18 #include <linux/clk-provider.h>
19 #include <linux/console.h>
20 #include <linux/sysrq.h>
21 #include <linux/tty_flip.h>
22 #include <linux/platform_device.h>
23 #include <linux/of.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/err.h>
31 #include <linux/irq.h>
32 #include <linux/suspend.h>
33 #include <linux/mm.h>
34 #include <linux/io.h>
35
36 #include <asm/div64.h>
37 #include <asm/ioctls.h>
38
39 #define PDC_BUFFER_SIZE 512
40 /* Revisit: We should calculate this based on the actual port settings */
41 #define PDC_RX_TIMEOUT (3 * 10) /* 3 bytes */
42
43 /* The minium number of data FIFOs should be able to contain */
44 #define ATMEL_MIN_FIFO_SIZE 8
45 /*
46 * These two offsets are substracted from the RX FIFO size to define the RTS
47 * high and low thresholds
48 */
49 #define ATMEL_RTS_HIGH_OFFSET 16
50 #define ATMEL_RTS_LOW_OFFSET 20
51
52 #include <linux/serial_core.h>
53
54 #include "serial_mctrl_gpio.h"
55 #include "atmel_serial.h"
56
57 static void atmel_start_rx(struct uart_port *port);
58 static void atmel_stop_rx(struct uart_port *port);
59
60 #ifdef CONFIG_SERIAL_ATMEL_TTYAT
61
62 /* Use device name ttyAT, major 204 and minor 154-169. This is necessary if we
63 * should coexist with the 8250 driver, such as if we have an external 16C550
64 * UART. */
65 #define SERIAL_ATMEL_MAJOR 204
66 #define MINOR_START 154
67 #define ATMEL_DEVICENAME "ttyAT"
68
69 #else
70
71 /* Use device name ttyS, major 4, minor 64-68. This is the usual serial port
72 * name, but it is legally reserved for the 8250 driver. */
73 #define SERIAL_ATMEL_MAJOR TTY_MAJOR
74 #define MINOR_START 64
75 #define ATMEL_DEVICENAME "ttyS"
76
77 #endif
78
79 #define ATMEL_ISR_PASS_LIMIT 256
80
81 struct atmel_dma_buffer {
82 unsigned char *buf;
83 dma_addr_t dma_addr;
84 unsigned int dma_size;
85 unsigned int ofs;
86 };
87
88 struct atmel_uart_char {
89 u16 status;
90 u16 ch;
91 };
92
93 /*
94 * Be careful, the real size of the ring buffer is
95 * sizeof(atmel_uart_char) * ATMEL_SERIAL_RINGSIZE. It means that ring buffer
96 * can contain up to 1024 characters in PIO mode and up to 4096 characters in
97 * DMA mode.
98 */
99 #define ATMEL_SERIAL_RINGSIZE 1024
100
101 /*
102 * at91: 6 USARTs and one DBGU port (SAM9260)
103 * samx7: 3 USARTs and 5 UARTs
104 */
105 #define ATMEL_MAX_UART 8
106
107 /*
108 * We wrap our port structure around the generic uart_port.
109 */
110 struct atmel_uart_port {
111 struct uart_port uart; /* uart */
112 struct clk *clk; /* uart clock */
113 struct clk *gclk; /* uart generic clock */
114 int may_wakeup; /* cached value of device_may_wakeup for times we need to disable it */
115 u32 backup_imr; /* IMR saved during suspend */
116 int break_active; /* break being received */
117
118 bool use_dma_rx; /* enable DMA receiver */
119 bool use_pdc_rx; /* enable PDC receiver */
120 short pdc_rx_idx; /* current PDC RX buffer */
121 struct atmel_dma_buffer pdc_rx[2]; /* PDC receier */
122
123 bool use_dma_tx; /* enable DMA transmitter */
124 bool use_pdc_tx; /* enable PDC transmitter */
125 struct atmel_dma_buffer pdc_tx; /* PDC transmitter */
126
127 spinlock_t lock_tx; /* port lock */
128 spinlock_t lock_rx; /* port lock */
129 struct dma_chan *chan_tx;
130 struct dma_chan *chan_rx;
131 struct dma_async_tx_descriptor *desc_tx;
132 struct dma_async_tx_descriptor *desc_rx;
133 dma_cookie_t cookie_tx;
134 dma_cookie_t cookie_rx;
135 struct scatterlist sg_tx;
136 struct scatterlist sg_rx;
137 struct tasklet_struct tasklet_rx;
138 struct tasklet_struct tasklet_tx;
139 atomic_t tasklet_shutdown;
140 unsigned int irq_status_prev;
141 unsigned int tx_len;
142
143 struct circ_buf rx_ring;
144
145 struct mctrl_gpios *gpios;
146 u32 backup_mode; /* MR saved during iso7816 operations */
147 u32 backup_brgr; /* BRGR saved during iso7816 operations */
148 unsigned int tx_done_mask;
149 u32 fifo_size;
150 u32 rts_high;
151 u32 rts_low;
152 bool ms_irq_enabled;
153 u32 rtor; /* address of receiver timeout register if it exists */
154 bool is_usart;
155 bool has_frac_baudrate;
156 bool has_hw_timer;
157 struct timer_list uart_timer;
158
159 bool tx_stopped;
160 bool suspended;
161 unsigned int pending;
162 unsigned int pending_status;
163 spinlock_t lock_suspended;
164
165 bool hd_start_rx; /* can start RX during half-duplex operation */
166
167 /* ISO7816 */
168 unsigned int fidi_min;
169 unsigned int fidi_max;
170
171 struct {
172 u32 cr;
173 u32 mr;
174 u32 imr;
175 u32 brgr;
176 u32 rtor;
177 u32 ttgr;
178 u32 fmr;
179 u32 fimr;
180 } cache;
181
182 int (*prepare_rx)(struct uart_port *port);
183 int (*prepare_tx)(struct uart_port *port);
184 void (*schedule_rx)(struct uart_port *port);
185 void (*schedule_tx)(struct uart_port *port);
186 void (*release_rx)(struct uart_port *port);
187 void (*release_tx)(struct uart_port *port);
188 };
189
190 static struct atmel_uart_port atmel_ports[ATMEL_MAX_UART];
191 static DECLARE_BITMAP(atmel_ports_in_use, ATMEL_MAX_UART);
192
193 #if defined(CONFIG_OF)
194 static const struct of_device_id atmel_serial_dt_ids[] = {
195 { .compatible = "atmel,at91rm9200-usart-serial" },
196 { /* sentinel */ }
197 };
198 #endif
199
200 static inline struct atmel_uart_port *
to_atmel_uart_port(struct uart_port * uart)201 to_atmel_uart_port(struct uart_port *uart)
202 {
203 return container_of(uart, struct atmel_uart_port, uart);
204 }
205
atmel_uart_readl(struct uart_port * port,u32 reg)206 static inline u32 atmel_uart_readl(struct uart_port *port, u32 reg)
207 {
208 return __raw_readl(port->membase + reg);
209 }
210
atmel_uart_writel(struct uart_port * port,u32 reg,u32 value)211 static inline void atmel_uart_writel(struct uart_port *port, u32 reg, u32 value)
212 {
213 __raw_writel(value, port->membase + reg);
214 }
215
atmel_uart_read_char(struct uart_port * port)216 static inline u8 atmel_uart_read_char(struct uart_port *port)
217 {
218 return __raw_readb(port->membase + ATMEL_US_RHR);
219 }
220
atmel_uart_write_char(struct uart_port * port,u8 value)221 static inline void atmel_uart_write_char(struct uart_port *port, u8 value)
222 {
223 __raw_writeb(value, port->membase + ATMEL_US_THR);
224 }
225
atmel_uart_is_half_duplex(struct uart_port * port)226 static inline int atmel_uart_is_half_duplex(struct uart_port *port)
227 {
228 return ((port->rs485.flags & SER_RS485_ENABLED) &&
229 !(port->rs485.flags & SER_RS485_RX_DURING_TX)) ||
230 (port->iso7816.flags & SER_ISO7816_ENABLED);
231 }
232
atmel_error_rate(int desired_value,int actual_value)233 static inline int atmel_error_rate(int desired_value, int actual_value)
234 {
235 return 100 - (desired_value * 100) / actual_value;
236 }
237
238 #ifdef CONFIG_SERIAL_ATMEL_PDC
atmel_use_pdc_rx(struct uart_port * port)239 static bool atmel_use_pdc_rx(struct uart_port *port)
240 {
241 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
242
243 return atmel_port->use_pdc_rx;
244 }
245
atmel_use_pdc_tx(struct uart_port * port)246 static bool atmel_use_pdc_tx(struct uart_port *port)
247 {
248 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
249
250 return atmel_port->use_pdc_tx;
251 }
252 #else
atmel_use_pdc_rx(struct uart_port * port)253 static bool atmel_use_pdc_rx(struct uart_port *port)
254 {
255 return false;
256 }
257
atmel_use_pdc_tx(struct uart_port * port)258 static bool atmel_use_pdc_tx(struct uart_port *port)
259 {
260 return false;
261 }
262 #endif
263
atmel_use_dma_tx(struct uart_port * port)264 static bool atmel_use_dma_tx(struct uart_port *port)
265 {
266 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
267
268 return atmel_port->use_dma_tx;
269 }
270
atmel_use_dma_rx(struct uart_port * port)271 static bool atmel_use_dma_rx(struct uart_port *port)
272 {
273 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
274
275 return atmel_port->use_dma_rx;
276 }
277
atmel_use_fifo(struct uart_port * port)278 static bool atmel_use_fifo(struct uart_port *port)
279 {
280 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
281
282 return atmel_port->fifo_size;
283 }
284
atmel_tasklet_schedule(struct atmel_uart_port * atmel_port,struct tasklet_struct * t)285 static void atmel_tasklet_schedule(struct atmel_uart_port *atmel_port,
286 struct tasklet_struct *t)
287 {
288 if (!atomic_read(&atmel_port->tasklet_shutdown))
289 tasklet_schedule(t);
290 }
291
292 /* Enable or disable the rs485 support */
atmel_config_rs485(struct uart_port * port,struct ktermios * termios,struct serial_rs485 * rs485conf)293 static int atmel_config_rs485(struct uart_port *port, struct ktermios *termios,
294 struct serial_rs485 *rs485conf)
295 {
296 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
297 unsigned int mode;
298
299 /* Disable interrupts */
300 atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask);
301
302 mode = atmel_uart_readl(port, ATMEL_US_MR);
303
304 if (rs485conf->flags & SER_RS485_ENABLED) {
305 dev_dbg(port->dev, "Setting UART to RS485\n");
306 if (rs485conf->flags & SER_RS485_RX_DURING_TX)
307 atmel_port->tx_done_mask = ATMEL_US_TXRDY;
308 else
309 atmel_port->tx_done_mask = ATMEL_US_TXEMPTY;
310
311 atmel_uart_writel(port, ATMEL_US_TTGR,
312 rs485conf->delay_rts_after_send);
313 mode &= ~ATMEL_US_USMODE;
314 mode |= ATMEL_US_USMODE_RS485;
315 } else {
316 dev_dbg(port->dev, "Setting UART to RS232\n");
317 if (atmel_use_pdc_tx(port))
318 atmel_port->tx_done_mask = ATMEL_US_ENDTX |
319 ATMEL_US_TXBUFE;
320 else
321 atmel_port->tx_done_mask = ATMEL_US_TXRDY;
322 }
323 atmel_uart_writel(port, ATMEL_US_MR, mode);
324
325 /* Enable interrupts */
326 atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask);
327
328 return 0;
329 }
330
atmel_calc_cd(struct uart_port * port,struct serial_iso7816 * iso7816conf)331 static unsigned int atmel_calc_cd(struct uart_port *port,
332 struct serial_iso7816 *iso7816conf)
333 {
334 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
335 unsigned int cd;
336 u64 mck_rate;
337
338 mck_rate = (u64)clk_get_rate(atmel_port->clk);
339 do_div(mck_rate, iso7816conf->clk);
340 cd = mck_rate;
341 return cd;
342 }
343
atmel_calc_fidi(struct uart_port * port,struct serial_iso7816 * iso7816conf)344 static unsigned int atmel_calc_fidi(struct uart_port *port,
345 struct serial_iso7816 *iso7816conf)
346 {
347 u64 fidi = 0;
348
349 if (iso7816conf->sc_fi && iso7816conf->sc_di) {
350 fidi = (u64)iso7816conf->sc_fi;
351 do_div(fidi, iso7816conf->sc_di);
352 }
353 return (u32)fidi;
354 }
355
356 /* Enable or disable the iso7816 support */
357 /* Called with interrupts disabled */
atmel_config_iso7816(struct uart_port * port,struct serial_iso7816 * iso7816conf)358 static int atmel_config_iso7816(struct uart_port *port,
359 struct serial_iso7816 *iso7816conf)
360 {
361 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
362 unsigned int mode;
363 unsigned int cd, fidi;
364 int ret = 0;
365
366 /* Disable interrupts */
367 atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask);
368
369 mode = atmel_uart_readl(port, ATMEL_US_MR);
370
371 if (iso7816conf->flags & SER_ISO7816_ENABLED) {
372 mode &= ~ATMEL_US_USMODE;
373
374 if (iso7816conf->tg > 255) {
375 dev_err(port->dev, "ISO7816: Timeguard exceeding 255\n");
376 memset(iso7816conf, 0, sizeof(struct serial_iso7816));
377 ret = -EINVAL;
378 goto err_out;
379 }
380
381 if ((iso7816conf->flags & SER_ISO7816_T_PARAM)
382 == SER_ISO7816_T(0)) {
383 mode |= ATMEL_US_USMODE_ISO7816_T0 | ATMEL_US_DSNACK;
384 } else if ((iso7816conf->flags & SER_ISO7816_T_PARAM)
385 == SER_ISO7816_T(1)) {
386 mode |= ATMEL_US_USMODE_ISO7816_T1 | ATMEL_US_INACK;
387 } else {
388 dev_err(port->dev, "ISO7816: Type not supported\n");
389 memset(iso7816conf, 0, sizeof(struct serial_iso7816));
390 ret = -EINVAL;
391 goto err_out;
392 }
393
394 mode &= ~(ATMEL_US_USCLKS | ATMEL_US_NBSTOP | ATMEL_US_PAR);
395
396 /* select mck clock, and output */
397 mode |= ATMEL_US_USCLKS_MCK | ATMEL_US_CLKO;
398 /* set parity for normal/inverse mode + max iterations */
399 mode |= ATMEL_US_PAR_EVEN | ATMEL_US_NBSTOP_1 | ATMEL_US_MAX_ITER(3);
400
401 cd = atmel_calc_cd(port, iso7816conf);
402 fidi = atmel_calc_fidi(port, iso7816conf);
403 if (fidi == 0) {
404 dev_warn(port->dev, "ISO7816 fidi = 0, Generator generates no signal\n");
405 } else if (fidi < atmel_port->fidi_min
406 || fidi > atmel_port->fidi_max) {
407 dev_err(port->dev, "ISO7816 fidi = %u, value not supported\n", fidi);
408 memset(iso7816conf, 0, sizeof(struct serial_iso7816));
409 ret = -EINVAL;
410 goto err_out;
411 }
412
413 if (!(port->iso7816.flags & SER_ISO7816_ENABLED)) {
414 /* port not yet in iso7816 mode: store configuration */
415 atmel_port->backup_mode = atmel_uart_readl(port, ATMEL_US_MR);
416 atmel_port->backup_brgr = atmel_uart_readl(port, ATMEL_US_BRGR);
417 }
418
419 atmel_uart_writel(port, ATMEL_US_TTGR, iso7816conf->tg);
420 atmel_uart_writel(port, ATMEL_US_BRGR, cd);
421 atmel_uart_writel(port, ATMEL_US_FIDI, fidi);
422
423 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXDIS | ATMEL_US_RXEN);
424 atmel_port->tx_done_mask = ATMEL_US_TXEMPTY | ATMEL_US_NACK | ATMEL_US_ITERATION;
425 } else {
426 dev_dbg(port->dev, "Setting UART back to RS232\n");
427 /* back to last RS232 settings */
428 mode = atmel_port->backup_mode;
429 memset(iso7816conf, 0, sizeof(struct serial_iso7816));
430 atmel_uart_writel(port, ATMEL_US_TTGR, 0);
431 atmel_uart_writel(port, ATMEL_US_BRGR, atmel_port->backup_brgr);
432 atmel_uart_writel(port, ATMEL_US_FIDI, 0x174);
433
434 if (atmel_use_pdc_tx(port))
435 atmel_port->tx_done_mask = ATMEL_US_ENDTX |
436 ATMEL_US_TXBUFE;
437 else
438 atmel_port->tx_done_mask = ATMEL_US_TXRDY;
439 }
440
441 port->iso7816 = *iso7816conf;
442
443 atmel_uart_writel(port, ATMEL_US_MR, mode);
444
445 err_out:
446 /* Enable interrupts */
447 atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask);
448
449 return ret;
450 }
451
452 /*
453 * Return TIOCSER_TEMT when transmitter FIFO and Shift register is empty.
454 */
atmel_tx_empty(struct uart_port * port)455 static u_int atmel_tx_empty(struct uart_port *port)
456 {
457 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
458
459 if (atmel_port->tx_stopped)
460 return TIOCSER_TEMT;
461 return (atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXEMPTY) ?
462 TIOCSER_TEMT :
463 0;
464 }
465
466 /*
467 * Set state of the modem control output lines
468 */
atmel_set_mctrl(struct uart_port * port,u_int mctrl)469 static void atmel_set_mctrl(struct uart_port *port, u_int mctrl)
470 {
471 unsigned int control = 0;
472 unsigned int mode = atmel_uart_readl(port, ATMEL_US_MR);
473 unsigned int rts_paused, rts_ready;
474 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
475
476 /* override mode to RS485 if needed, otherwise keep the current mode */
477 if (port->rs485.flags & SER_RS485_ENABLED) {
478 atmel_uart_writel(port, ATMEL_US_TTGR,
479 port->rs485.delay_rts_after_send);
480 mode &= ~ATMEL_US_USMODE;
481 mode |= ATMEL_US_USMODE_RS485;
482 }
483
484 /* set the RTS line state according to the mode */
485 if ((mode & ATMEL_US_USMODE) == ATMEL_US_USMODE_HWHS) {
486 /* force RTS line to high level */
487 rts_paused = ATMEL_US_RTSEN;
488
489 /* give the control of the RTS line back to the hardware */
490 rts_ready = ATMEL_US_RTSDIS;
491 } else {
492 /* force RTS line to high level */
493 rts_paused = ATMEL_US_RTSDIS;
494
495 /* force RTS line to low level */
496 rts_ready = ATMEL_US_RTSEN;
497 }
498
499 if (mctrl & TIOCM_RTS)
500 control |= rts_ready;
501 else
502 control |= rts_paused;
503
504 if (mctrl & TIOCM_DTR)
505 control |= ATMEL_US_DTREN;
506 else
507 control |= ATMEL_US_DTRDIS;
508
509 atmel_uart_writel(port, ATMEL_US_CR, control);
510
511 mctrl_gpio_set(atmel_port->gpios, mctrl);
512
513 /* Local loopback mode? */
514 mode &= ~ATMEL_US_CHMODE;
515 if (mctrl & TIOCM_LOOP)
516 mode |= ATMEL_US_CHMODE_LOC_LOOP;
517 else
518 mode |= ATMEL_US_CHMODE_NORMAL;
519
520 atmel_uart_writel(port, ATMEL_US_MR, mode);
521 }
522
523 /*
524 * Get state of the modem control input lines
525 */
atmel_get_mctrl(struct uart_port * port)526 static u_int atmel_get_mctrl(struct uart_port *port)
527 {
528 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
529 unsigned int ret = 0, status;
530
531 status = atmel_uart_readl(port, ATMEL_US_CSR);
532
533 /*
534 * The control signals are active low.
535 */
536 if (!(status & ATMEL_US_DCD))
537 ret |= TIOCM_CD;
538 if (!(status & ATMEL_US_CTS))
539 ret |= TIOCM_CTS;
540 if (!(status & ATMEL_US_DSR))
541 ret |= TIOCM_DSR;
542 if (!(status & ATMEL_US_RI))
543 ret |= TIOCM_RI;
544
545 return mctrl_gpio_get(atmel_port->gpios, &ret);
546 }
547
548 /*
549 * Stop transmitting.
550 */
atmel_stop_tx(struct uart_port * port)551 static void atmel_stop_tx(struct uart_port *port)
552 {
553 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
554 bool is_pdc = atmel_use_pdc_tx(port);
555 bool is_dma = is_pdc || atmel_use_dma_tx(port);
556
557 if (is_pdc) {
558 /* disable PDC transmit */
559 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTDIS);
560 }
561
562 if (is_dma) {
563 /*
564 * Disable the transmitter.
565 * This is mandatory when DMA is used, otherwise the DMA buffer
566 * is fully transmitted.
567 */
568 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXDIS);
569 atmel_port->tx_stopped = true;
570 }
571
572 /* Disable interrupts */
573 atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask);
574
575 if (atmel_uart_is_half_duplex(port))
576 if (!atomic_read(&atmel_port->tasklet_shutdown))
577 atmel_start_rx(port);
578 }
579
580 /*
581 * Start transmitting.
582 */
atmel_start_tx(struct uart_port * port)583 static void atmel_start_tx(struct uart_port *port)
584 {
585 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
586 bool is_pdc = atmel_use_pdc_tx(port);
587 bool is_dma = is_pdc || atmel_use_dma_tx(port);
588
589 if (is_pdc && (atmel_uart_readl(port, ATMEL_PDC_PTSR)
590 & ATMEL_PDC_TXTEN))
591 /* The transmitter is already running. Yes, we
592 really need this.*/
593 return;
594
595 if (is_dma && atmel_uart_is_half_duplex(port))
596 atmel_stop_rx(port);
597
598 if (is_pdc) {
599 /* re-enable PDC transmit */
600 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTEN);
601 }
602
603 /* Enable interrupts */
604 atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask);
605
606 if (is_dma) {
607 /* re-enable the transmitter */
608 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN);
609 atmel_port->tx_stopped = false;
610 }
611 }
612
613 /*
614 * start receiving - port is in process of being opened.
615 */
atmel_start_rx(struct uart_port * port)616 static void atmel_start_rx(struct uart_port *port)
617 {
618 /* reset status and receiver */
619 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA);
620
621 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RXEN);
622
623 if (atmel_use_pdc_rx(port)) {
624 /* enable PDC controller */
625 atmel_uart_writel(port, ATMEL_US_IER,
626 ATMEL_US_ENDRX | ATMEL_US_TIMEOUT |
627 port->read_status_mask);
628 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_RXTEN);
629 } else {
630 atmel_uart_writel(port, ATMEL_US_IER, ATMEL_US_RXRDY);
631 }
632 }
633
634 /*
635 * Stop receiving - port is in process of being closed.
636 */
atmel_stop_rx(struct uart_port * port)637 static void atmel_stop_rx(struct uart_port *port)
638 {
639 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RXDIS);
640
641 if (atmel_use_pdc_rx(port)) {
642 /* disable PDC receive */
643 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_RXTDIS);
644 atmel_uart_writel(port, ATMEL_US_IDR,
645 ATMEL_US_ENDRX | ATMEL_US_TIMEOUT |
646 port->read_status_mask);
647 } else {
648 atmel_uart_writel(port, ATMEL_US_IDR, ATMEL_US_RXRDY);
649 }
650 }
651
652 /*
653 * Enable modem status interrupts
654 */
atmel_enable_ms(struct uart_port * port)655 static void atmel_enable_ms(struct uart_port *port)
656 {
657 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
658 uint32_t ier = 0;
659
660 /*
661 * Interrupt should not be enabled twice
662 */
663 if (atmel_port->ms_irq_enabled)
664 return;
665
666 atmel_port->ms_irq_enabled = true;
667
668 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS))
669 ier |= ATMEL_US_CTSIC;
670
671 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_DSR))
672 ier |= ATMEL_US_DSRIC;
673
674 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_RI))
675 ier |= ATMEL_US_RIIC;
676
677 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_DCD))
678 ier |= ATMEL_US_DCDIC;
679
680 atmel_uart_writel(port, ATMEL_US_IER, ier);
681
682 mctrl_gpio_enable_ms(atmel_port->gpios);
683 }
684
685 /*
686 * Disable modem status interrupts
687 */
atmel_disable_ms(struct uart_port * port)688 static void atmel_disable_ms(struct uart_port *port)
689 {
690 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
691 uint32_t idr = 0;
692
693 /*
694 * Interrupt should not be disabled twice
695 */
696 if (!atmel_port->ms_irq_enabled)
697 return;
698
699 atmel_port->ms_irq_enabled = false;
700
701 mctrl_gpio_disable_ms(atmel_port->gpios);
702
703 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS))
704 idr |= ATMEL_US_CTSIC;
705
706 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_DSR))
707 idr |= ATMEL_US_DSRIC;
708
709 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_RI))
710 idr |= ATMEL_US_RIIC;
711
712 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_DCD))
713 idr |= ATMEL_US_DCDIC;
714
715 atmel_uart_writel(port, ATMEL_US_IDR, idr);
716 }
717
718 /*
719 * Control the transmission of a break signal
720 */
atmel_break_ctl(struct uart_port * port,int break_state)721 static void atmel_break_ctl(struct uart_port *port, int break_state)
722 {
723 if (break_state != 0)
724 /* start break */
725 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STTBRK);
726 else
727 /* stop break */
728 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STPBRK);
729 }
730
731 /*
732 * Stores the incoming character in the ring buffer
733 */
734 static void
atmel_buffer_rx_char(struct uart_port * port,unsigned int status,unsigned int ch)735 atmel_buffer_rx_char(struct uart_port *port, unsigned int status,
736 unsigned int ch)
737 {
738 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
739 struct circ_buf *ring = &atmel_port->rx_ring;
740 struct atmel_uart_char *c;
741
742 if (!CIRC_SPACE(ring->head, ring->tail, ATMEL_SERIAL_RINGSIZE))
743 /* Buffer overflow, ignore char */
744 return;
745
746 c = &((struct atmel_uart_char *)ring->buf)[ring->head];
747 c->status = status;
748 c->ch = ch;
749
750 /* Make sure the character is stored before we update head. */
751 smp_wmb();
752
753 ring->head = (ring->head + 1) & (ATMEL_SERIAL_RINGSIZE - 1);
754 }
755
756 /*
757 * Deal with parity, framing and overrun errors.
758 */
atmel_pdc_rxerr(struct uart_port * port,unsigned int status)759 static void atmel_pdc_rxerr(struct uart_port *port, unsigned int status)
760 {
761 /* clear error */
762 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA);
763
764 if (status & ATMEL_US_RXBRK) {
765 /* ignore side-effect */
766 status &= ~(ATMEL_US_PARE | ATMEL_US_FRAME);
767 port->icount.brk++;
768 }
769 if (status & ATMEL_US_PARE)
770 port->icount.parity++;
771 if (status & ATMEL_US_FRAME)
772 port->icount.frame++;
773 if (status & ATMEL_US_OVRE)
774 port->icount.overrun++;
775 }
776
777 /*
778 * Characters received (called from interrupt handler)
779 */
atmel_rx_chars(struct uart_port * port)780 static void atmel_rx_chars(struct uart_port *port)
781 {
782 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
783 unsigned int status, ch;
784
785 status = atmel_uart_readl(port, ATMEL_US_CSR);
786 while (status & ATMEL_US_RXRDY) {
787 ch = atmel_uart_read_char(port);
788
789 /*
790 * note that the error handling code is
791 * out of the main execution path
792 */
793 if (unlikely(status & (ATMEL_US_PARE | ATMEL_US_FRAME
794 | ATMEL_US_OVRE | ATMEL_US_RXBRK)
795 || atmel_port->break_active)) {
796
797 /* clear error */
798 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA);
799
800 if (status & ATMEL_US_RXBRK
801 && !atmel_port->break_active) {
802 atmel_port->break_active = 1;
803 atmel_uart_writel(port, ATMEL_US_IER,
804 ATMEL_US_RXBRK);
805 } else {
806 /*
807 * This is either the end-of-break
808 * condition or we've received at
809 * least one character without RXBRK
810 * being set. In both cases, the next
811 * RXBRK will indicate start-of-break.
812 */
813 atmel_uart_writel(port, ATMEL_US_IDR,
814 ATMEL_US_RXBRK);
815 status &= ~ATMEL_US_RXBRK;
816 atmel_port->break_active = 0;
817 }
818 }
819
820 atmel_buffer_rx_char(port, status, ch);
821 status = atmel_uart_readl(port, ATMEL_US_CSR);
822 }
823
824 atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_rx);
825 }
826
827 /*
828 * Transmit characters (called from tasklet with TXRDY interrupt
829 * disabled)
830 */
atmel_tx_chars(struct uart_port * port)831 static void atmel_tx_chars(struct uart_port *port)
832 {
833 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
834 bool pending;
835 u8 ch;
836
837 pending = uart_port_tx(port, ch,
838 atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXRDY,
839 atmel_uart_write_char(port, ch));
840 if (pending) {
841 /* we still have characters to transmit, so we should continue
842 * transmitting them when TX is ready, regardless of
843 * mode or duplexity
844 */
845 atmel_port->tx_done_mask |= ATMEL_US_TXRDY;
846
847 /* Enable interrupts */
848 atmel_uart_writel(port, ATMEL_US_IER,
849 atmel_port->tx_done_mask);
850 } else {
851 if (atmel_uart_is_half_duplex(port))
852 atmel_port->tx_done_mask &= ~ATMEL_US_TXRDY;
853 }
854 }
855
atmel_complete_tx_dma(void * arg)856 static void atmel_complete_tx_dma(void *arg)
857 {
858 struct atmel_uart_port *atmel_port = arg;
859 struct uart_port *port = &atmel_port->uart;
860 struct circ_buf *xmit = &port->state->xmit;
861 struct dma_chan *chan = atmel_port->chan_tx;
862 unsigned long flags;
863
864 spin_lock_irqsave(&port->lock, flags);
865
866 if (chan)
867 dmaengine_terminate_all(chan);
868 uart_xmit_advance(port, atmel_port->tx_len);
869
870 spin_lock(&atmel_port->lock_tx);
871 async_tx_ack(atmel_port->desc_tx);
872 atmel_port->cookie_tx = -EINVAL;
873 atmel_port->desc_tx = NULL;
874 spin_unlock(&atmel_port->lock_tx);
875
876 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
877 uart_write_wakeup(port);
878
879 /*
880 * xmit is a circular buffer so, if we have just send data from
881 * xmit->tail to the end of xmit->buf, now we have to transmit the
882 * remaining data from the beginning of xmit->buf to xmit->head.
883 */
884 if (!uart_circ_empty(xmit))
885 atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_tx);
886 else if (atmel_uart_is_half_duplex(port)) {
887 /*
888 * DMA done, re-enable TXEMPTY and signal that we can stop
889 * TX and start RX for RS485
890 */
891 atmel_port->hd_start_rx = true;
892 atmel_uart_writel(port, ATMEL_US_IER,
893 atmel_port->tx_done_mask);
894 }
895
896 spin_unlock_irqrestore(&port->lock, flags);
897 }
898
atmel_release_tx_dma(struct uart_port * port)899 static void atmel_release_tx_dma(struct uart_port *port)
900 {
901 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
902 struct dma_chan *chan = atmel_port->chan_tx;
903
904 if (chan) {
905 dmaengine_terminate_all(chan);
906 dma_release_channel(chan);
907 dma_unmap_sg(port->dev, &atmel_port->sg_tx, 1,
908 DMA_TO_DEVICE);
909 }
910
911 atmel_port->desc_tx = NULL;
912 atmel_port->chan_tx = NULL;
913 atmel_port->cookie_tx = -EINVAL;
914 }
915
916 /*
917 * Called from tasklet with TXRDY interrupt is disabled.
918 */
atmel_tx_dma(struct uart_port * port)919 static void atmel_tx_dma(struct uart_port *port)
920 {
921 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
922 struct circ_buf *xmit = &port->state->xmit;
923 struct dma_chan *chan = atmel_port->chan_tx;
924 struct dma_async_tx_descriptor *desc;
925 struct scatterlist sgl[2], *sg, *sg_tx = &atmel_port->sg_tx;
926 unsigned int tx_len, part1_len, part2_len, sg_len;
927 dma_addr_t phys_addr;
928
929 /* Make sure we have an idle channel */
930 if (atmel_port->desc_tx != NULL)
931 return;
932
933 if (!uart_circ_empty(xmit) && !uart_tx_stopped(port)) {
934 /*
935 * DMA is idle now.
936 * Port xmit buffer is already mapped,
937 * and it is one page... Just adjust
938 * offsets and lengths. Since it is a circular buffer,
939 * we have to transmit till the end, and then the rest.
940 * Take the port lock to get a
941 * consistent xmit buffer state.
942 */
943 tx_len = CIRC_CNT_TO_END(xmit->head,
944 xmit->tail,
945 UART_XMIT_SIZE);
946
947 if (atmel_port->fifo_size) {
948 /* multi data mode */
949 part1_len = (tx_len & ~0x3); /* DWORD access */
950 part2_len = (tx_len & 0x3); /* BYTE access */
951 } else {
952 /* single data (legacy) mode */
953 part1_len = 0;
954 part2_len = tx_len; /* BYTE access only */
955 }
956
957 sg_init_table(sgl, 2);
958 sg_len = 0;
959 phys_addr = sg_dma_address(sg_tx) + xmit->tail;
960 if (part1_len) {
961 sg = &sgl[sg_len++];
962 sg_dma_address(sg) = phys_addr;
963 sg_dma_len(sg) = part1_len;
964
965 phys_addr += part1_len;
966 }
967
968 if (part2_len) {
969 sg = &sgl[sg_len++];
970 sg_dma_address(sg) = phys_addr;
971 sg_dma_len(sg) = part2_len;
972 }
973
974 /*
975 * save tx_len so atmel_complete_tx_dma() will increase
976 * xmit->tail correctly
977 */
978 atmel_port->tx_len = tx_len;
979
980 desc = dmaengine_prep_slave_sg(chan,
981 sgl,
982 sg_len,
983 DMA_MEM_TO_DEV,
984 DMA_PREP_INTERRUPT |
985 DMA_CTRL_ACK);
986 if (!desc) {
987 dev_err(port->dev, "Failed to send via dma!\n");
988 return;
989 }
990
991 dma_sync_sg_for_device(port->dev, sg_tx, 1, DMA_TO_DEVICE);
992
993 atmel_port->desc_tx = desc;
994 desc->callback = atmel_complete_tx_dma;
995 desc->callback_param = atmel_port;
996 atmel_port->cookie_tx = dmaengine_submit(desc);
997 if (dma_submit_error(atmel_port->cookie_tx)) {
998 dev_err(port->dev, "dma_submit_error %d\n",
999 atmel_port->cookie_tx);
1000 return;
1001 }
1002
1003 dma_async_issue_pending(chan);
1004 }
1005
1006 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
1007 uart_write_wakeup(port);
1008 }
1009
atmel_prepare_tx_dma(struct uart_port * port)1010 static int atmel_prepare_tx_dma(struct uart_port *port)
1011 {
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;
1016 int ret, nent;
1017
1018 dma_cap_zero(mask);
1019 dma_cap_set(DMA_SLAVE, mask);
1020
1021 atmel_port->chan_tx = dma_request_slave_channel(mfd_dev, "tx");
1022 if (atmel_port->chan_tx == NULL)
1023 goto chan_err;
1024 dev_info(port->dev, "using %s for tx DMA transfers\n",
1025 dma_chan_name(atmel_port->chan_tx));
1026
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),
1033 UART_XMIT_SIZE,
1034 offset_in_page(port->state->xmit.buf));
1035 nent = dma_map_sg(port->dev,
1036 &atmel_port->sg_tx,
1037 1,
1038 DMA_TO_DEVICE);
1039
1040 if (!nent) {
1041 dev_dbg(port->dev, "need to release resource of dma\n");
1042 goto chan_err;
1043 } else {
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));
1048 }
1049
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;
1058
1059 ret = dmaengine_slave_config(atmel_port->chan_tx,
1060 &config);
1061 if (ret) {
1062 dev_err(port->dev, "DMA tx slave configuration failed\n");
1063 goto chan_err;
1064 }
1065
1066 return 0;
1067
1068 chan_err:
1069 dev_err(port->dev, "TX channel not available, switch to pio\n");
1070 atmel_port->use_dma_tx = false;
1071 if (atmel_port->chan_tx)
1072 atmel_release_tx_dma(port);
1073 return -EINVAL;
1074 }
1075
atmel_complete_rx_dma(void * arg)1076 static void atmel_complete_rx_dma(void *arg)
1077 {
1078 struct uart_port *port = arg;
1079 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1080
1081 atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_rx);
1082 }
1083
atmel_release_rx_dma(struct uart_port * port)1084 static void atmel_release_rx_dma(struct uart_port *port)
1085 {
1086 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1087 struct dma_chan *chan = atmel_port->chan_rx;
1088
1089 if (chan) {
1090 dmaengine_terminate_all(chan);
1091 dma_release_channel(chan);
1092 dma_unmap_sg(port->dev, &atmel_port->sg_rx, 1,
1093 DMA_FROM_DEVICE);
1094 }
1095
1096 atmel_port->desc_rx = NULL;
1097 atmel_port->chan_rx = NULL;
1098 atmel_port->cookie_rx = -EINVAL;
1099 }
1100
atmel_rx_from_dma(struct uart_port * port)1101 static void atmel_rx_from_dma(struct uart_port *port)
1102 {
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;
1109 size_t count;
1110
1111
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,
1116 &state);
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);
1122 return;
1123 }
1124
1125 /* CPU claims ownership of RX DMA buffer */
1126 dma_sync_sg_for_cpu(port->dev,
1127 &atmel_port->sg_rx,
1128 1,
1129 DMA_FROM_DEVICE);
1130
1131 /*
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
1134 * framework.
1135 * The current transfer size should not be larger than the dma buffer
1136 * length.
1137 */
1138 ring->head = sg_dma_len(&atmel_port->sg_rx) - state.residue;
1139 BUG_ON(ring->head > sg_dma_len(&atmel_port->sg_rx));
1140 /*
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)
1144 *
1145 * However ring->tail must always points inside the dma buffer:
1146 * 0 <= ring->tail <= sg_dma_len(&atmel_port->sg_rx) - 1
1147 *
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.
1151 */
1152 if (ring->head < ring->tail) {
1153 count = sg_dma_len(&atmel_port->sg_rx) - ring->tail;
1154
1155 tty_insert_flip_string(tport, ring->buf + ring->tail, count);
1156 ring->tail = 0;
1157 port->icount.rx += count;
1158 }
1159
1160 /* Finally we read data from tail to head */
1161 if (ring->tail < ring->head) {
1162 count = ring->head - ring->tail;
1163
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))
1167 ring->head = 0;
1168 ring->tail = ring->head;
1169 port->icount.rx += count;
1170 }
1171
1172 /* USART retreives ownership of RX DMA buffer */
1173 dma_sync_sg_for_device(port->dev,
1174 &atmel_port->sg_rx,
1175 1,
1176 DMA_FROM_DEVICE);
1177
1178 tty_flip_buffer_push(tport);
1179
1180 atmel_uart_writel(port, ATMEL_US_IER, ATMEL_US_TIMEOUT);
1181 }
1182
atmel_prepare_rx_dma(struct uart_port * port)1183 static int atmel_prepare_rx_dma(struct uart_port *port)
1184 {
1185 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1186 struct device *mfd_dev = port->dev->parent;
1187 struct dma_async_tx_descriptor *desc;
1188 dma_cap_mask_t mask;
1189 struct dma_slave_config config;
1190 struct circ_buf *ring;
1191 int ret, nent;
1192
1193 ring = &atmel_port->rx_ring;
1194
1195 dma_cap_zero(mask);
1196 dma_cap_set(DMA_CYCLIC, mask);
1197
1198 atmel_port->chan_rx = dma_request_slave_channel(mfd_dev, "rx");
1199 if (atmel_port->chan_rx == NULL)
1200 goto chan_err;
1201 dev_info(port->dev, "using %s for rx DMA transfers\n",
1202 dma_chan_name(atmel_port->chan_rx));
1203
1204 spin_lock_init(&atmel_port->lock_rx);
1205 sg_init_table(&atmel_port->sg_rx, 1);
1206 /* UART circular rx buffer is an aligned page. */
1207 BUG_ON(!PAGE_ALIGNED(ring->buf));
1208 sg_set_page(&atmel_port->sg_rx,
1209 virt_to_page(ring->buf),
1210 sizeof(struct atmel_uart_char) * ATMEL_SERIAL_RINGSIZE,
1211 offset_in_page(ring->buf));
1212 nent = dma_map_sg(port->dev,
1213 &atmel_port->sg_rx,
1214 1,
1215 DMA_FROM_DEVICE);
1216
1217 if (!nent) {
1218 dev_dbg(port->dev, "need to release resource of dma\n");
1219 goto chan_err;
1220 } else {
1221 dev_dbg(port->dev, "%s: mapped %d@%p to %pad\n", __func__,
1222 sg_dma_len(&atmel_port->sg_rx),
1223 ring->buf,
1224 &sg_dma_address(&atmel_port->sg_rx));
1225 }
1226
1227 /* Configure the slave DMA */
1228 memset(&config, 0, sizeof(config));
1229 config.direction = DMA_DEV_TO_MEM;
1230 config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1231 config.src_addr = port->mapbase + ATMEL_US_RHR;
1232 config.src_maxburst = 1;
1233
1234 ret = dmaengine_slave_config(atmel_port->chan_rx,
1235 &config);
1236 if (ret) {
1237 dev_err(port->dev, "DMA rx slave configuration failed\n");
1238 goto chan_err;
1239 }
1240 /*
1241 * Prepare a cyclic dma transfer, assign 2 descriptors,
1242 * each one is half ring buffer size
1243 */
1244 desc = dmaengine_prep_dma_cyclic(atmel_port->chan_rx,
1245 sg_dma_address(&atmel_port->sg_rx),
1246 sg_dma_len(&atmel_port->sg_rx),
1247 sg_dma_len(&atmel_port->sg_rx)/2,
1248 DMA_DEV_TO_MEM,
1249 DMA_PREP_INTERRUPT);
1250 if (!desc) {
1251 dev_err(port->dev, "Preparing DMA cyclic failed\n");
1252 goto chan_err;
1253 }
1254 desc->callback = atmel_complete_rx_dma;
1255 desc->callback_param = port;
1256 atmel_port->desc_rx = desc;
1257 atmel_port->cookie_rx = dmaengine_submit(desc);
1258 if (dma_submit_error(atmel_port->cookie_rx)) {
1259 dev_err(port->dev, "dma_submit_error %d\n",
1260 atmel_port->cookie_rx);
1261 goto chan_err;
1262 }
1263
1264 dma_async_issue_pending(atmel_port->chan_rx);
1265
1266 return 0;
1267
1268 chan_err:
1269 dev_err(port->dev, "RX channel not available, switch to pio\n");
1270 atmel_port->use_dma_rx = false;
1271 if (atmel_port->chan_rx)
1272 atmel_release_rx_dma(port);
1273 return -EINVAL;
1274 }
1275
atmel_uart_timer_callback(struct timer_list * t)1276 static void atmel_uart_timer_callback(struct timer_list *t)
1277 {
1278 struct atmel_uart_port *atmel_port = from_timer(atmel_port, t,
1279 uart_timer);
1280 struct uart_port *port = &atmel_port->uart;
1281
1282 if (!atomic_read(&atmel_port->tasklet_shutdown)) {
1283 tasklet_schedule(&atmel_port->tasklet_rx);
1284 mod_timer(&atmel_port->uart_timer,
1285 jiffies + uart_poll_timeout(port));
1286 }
1287 }
1288
1289 /*
1290 * receive interrupt handler.
1291 */
1292 static void
atmel_handle_receive(struct uart_port * port,unsigned int pending)1293 atmel_handle_receive(struct uart_port *port, unsigned int pending)
1294 {
1295 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1296
1297 if (atmel_use_pdc_rx(port)) {
1298 /*
1299 * PDC receive. Just schedule the tasklet and let it
1300 * figure out the details.
1301 *
1302 * TODO: We're not handling error flags correctly at
1303 * the moment.
1304 */
1305 if (pending & (ATMEL_US_ENDRX | ATMEL_US_TIMEOUT)) {
1306 atmel_uart_writel(port, ATMEL_US_IDR,
1307 (ATMEL_US_ENDRX | ATMEL_US_TIMEOUT));
1308 atmel_tasklet_schedule(atmel_port,
1309 &atmel_port->tasklet_rx);
1310 }
1311
1312 if (pending & (ATMEL_US_RXBRK | ATMEL_US_OVRE |
1313 ATMEL_US_FRAME | ATMEL_US_PARE))
1314 atmel_pdc_rxerr(port, pending);
1315 }
1316
1317 if (atmel_use_dma_rx(port)) {
1318 if (pending & ATMEL_US_TIMEOUT) {
1319 atmel_uart_writel(port, ATMEL_US_IDR,
1320 ATMEL_US_TIMEOUT);
1321 atmel_tasklet_schedule(atmel_port,
1322 &atmel_port->tasklet_rx);
1323 }
1324 }
1325
1326 /* Interrupt receive */
1327 if (pending & ATMEL_US_RXRDY)
1328 atmel_rx_chars(port);
1329 else if (pending & ATMEL_US_RXBRK) {
1330 /*
1331 * End of break detected. If it came along with a
1332 * character, atmel_rx_chars will handle it.
1333 */
1334 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA);
1335 atmel_uart_writel(port, ATMEL_US_IDR, ATMEL_US_RXBRK);
1336 atmel_port->break_active = 0;
1337 }
1338 }
1339
1340 /*
1341 * transmit interrupt handler. (Transmit is IRQF_NODELAY safe)
1342 */
1343 static void
atmel_handle_transmit(struct uart_port * port,unsigned int pending)1344 atmel_handle_transmit(struct uart_port *port, unsigned int pending)
1345 {
1346 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1347
1348 if (pending & atmel_port->tx_done_mask) {
1349 atmel_uart_writel(port, ATMEL_US_IDR,
1350 atmel_port->tx_done_mask);
1351
1352 /* Start RX if flag was set and FIFO is empty */
1353 if (atmel_port->hd_start_rx) {
1354 if (!(atmel_uart_readl(port, ATMEL_US_CSR)
1355 & ATMEL_US_TXEMPTY))
1356 dev_warn(port->dev, "Should start RX, but TX fifo is not empty\n");
1357
1358 atmel_port->hd_start_rx = false;
1359 atmel_start_rx(port);
1360 }
1361
1362 atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_tx);
1363 }
1364 }
1365
1366 /*
1367 * status flags interrupt handler.
1368 */
1369 static void
atmel_handle_status(struct uart_port * port,unsigned int pending,unsigned int status)1370 atmel_handle_status(struct uart_port *port, unsigned int pending,
1371 unsigned int status)
1372 {
1373 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1374 unsigned int status_change;
1375
1376 if (pending & (ATMEL_US_RIIC | ATMEL_US_DSRIC | ATMEL_US_DCDIC
1377 | ATMEL_US_CTSIC)) {
1378 status_change = status ^ atmel_port->irq_status_prev;
1379 atmel_port->irq_status_prev = status;
1380
1381 if (status_change & (ATMEL_US_RI | ATMEL_US_DSR
1382 | ATMEL_US_DCD | ATMEL_US_CTS)) {
1383 /* TODO: All reads to CSR will clear these interrupts! */
1384 if (status_change & ATMEL_US_RI)
1385 port->icount.rng++;
1386 if (status_change & ATMEL_US_DSR)
1387 port->icount.dsr++;
1388 if (status_change & ATMEL_US_DCD)
1389 uart_handle_dcd_change(port, !(status & ATMEL_US_DCD));
1390 if (status_change & ATMEL_US_CTS)
1391 uart_handle_cts_change(port, !(status & ATMEL_US_CTS));
1392
1393 wake_up_interruptible(&port->state->port.delta_msr_wait);
1394 }
1395 }
1396
1397 if (pending & (ATMEL_US_NACK | ATMEL_US_ITERATION))
1398 dev_dbg(port->dev, "ISO7816 ERROR (0x%08x)\n", pending);
1399 }
1400
1401 /*
1402 * Interrupt handler
1403 */
atmel_interrupt(int irq,void * dev_id)1404 static irqreturn_t atmel_interrupt(int irq, void *dev_id)
1405 {
1406 struct uart_port *port = dev_id;
1407 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1408 unsigned int status, pending, mask, pass_counter = 0;
1409
1410 spin_lock(&atmel_port->lock_suspended);
1411
1412 do {
1413 status = atmel_uart_readl(port, ATMEL_US_CSR);
1414 mask = atmel_uart_readl(port, ATMEL_US_IMR);
1415 pending = status & mask;
1416 if (!pending)
1417 break;
1418
1419 if (atmel_port->suspended) {
1420 atmel_port->pending |= pending;
1421 atmel_port->pending_status = status;
1422 atmel_uart_writel(port, ATMEL_US_IDR, mask);
1423 pm_system_wakeup();
1424 break;
1425 }
1426
1427 atmel_handle_receive(port, pending);
1428 atmel_handle_status(port, pending, status);
1429 atmel_handle_transmit(port, pending);
1430 } while (pass_counter++ < ATMEL_ISR_PASS_LIMIT);
1431
1432 spin_unlock(&atmel_port->lock_suspended);
1433
1434 return pass_counter ? IRQ_HANDLED : IRQ_NONE;
1435 }
1436
atmel_release_tx_pdc(struct uart_port * port)1437 static void atmel_release_tx_pdc(struct uart_port *port)
1438 {
1439 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1440 struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;
1441
1442 dma_unmap_single(port->dev,
1443 pdc->dma_addr,
1444 pdc->dma_size,
1445 DMA_TO_DEVICE);
1446 }
1447
1448 /*
1449 * Called from tasklet with ENDTX and TXBUFE interrupts disabled.
1450 */
atmel_tx_pdc(struct uart_port * port)1451 static void atmel_tx_pdc(struct uart_port *port)
1452 {
1453 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1454 struct circ_buf *xmit = &port->state->xmit;
1455 struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;
1456 int count;
1457
1458 /* nothing left to transmit? */
1459 if (atmel_uart_readl(port, ATMEL_PDC_TCR))
1460 return;
1461 uart_xmit_advance(port, pdc->ofs);
1462 pdc->ofs = 0;
1463
1464 /* more to transmit - setup next transfer */
1465
1466 /* disable PDC transmit */
1467 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTDIS);
1468
1469 if (!uart_circ_empty(xmit) && !uart_tx_stopped(port)) {
1470 dma_sync_single_for_device(port->dev,
1471 pdc->dma_addr,
1472 pdc->dma_size,
1473 DMA_TO_DEVICE);
1474
1475 count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
1476 pdc->ofs = count;
1477
1478 atmel_uart_writel(port, ATMEL_PDC_TPR,
1479 pdc->dma_addr + xmit->tail);
1480 atmel_uart_writel(port, ATMEL_PDC_TCR, count);
1481 /* re-enable PDC transmit */
1482 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTEN);
1483 /* Enable interrupts */
1484 atmel_uart_writel(port, ATMEL_US_IER,
1485 atmel_port->tx_done_mask);
1486 } else {
1487 if (atmel_uart_is_half_duplex(port)) {
1488 /* DMA done, stop TX, start RX for RS485 */
1489 atmel_start_rx(port);
1490 }
1491 }
1492
1493 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
1494 uart_write_wakeup(port);
1495 }
1496
atmel_prepare_tx_pdc(struct uart_port * port)1497 static int atmel_prepare_tx_pdc(struct uart_port *port)
1498 {
1499 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1500 struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;
1501 struct circ_buf *xmit = &port->state->xmit;
1502
1503 pdc->buf = xmit->buf;
1504 pdc->dma_addr = dma_map_single(port->dev,
1505 pdc->buf,
1506 UART_XMIT_SIZE,
1507 DMA_TO_DEVICE);
1508 pdc->dma_size = UART_XMIT_SIZE;
1509 pdc->ofs = 0;
1510
1511 return 0;
1512 }
1513
atmel_rx_from_ring(struct uart_port * port)1514 static void atmel_rx_from_ring(struct uart_port *port)
1515 {
1516 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1517 struct circ_buf *ring = &atmel_port->rx_ring;
1518 unsigned int status;
1519 u8 flg;
1520
1521 while (ring->head != ring->tail) {
1522 struct atmel_uart_char c;
1523
1524 /* Make sure c is loaded after head. */
1525 smp_rmb();
1526
1527 c = ((struct atmel_uart_char *)ring->buf)[ring->tail];
1528
1529 ring->tail = (ring->tail + 1) & (ATMEL_SERIAL_RINGSIZE - 1);
1530
1531 port->icount.rx++;
1532 status = c.status;
1533 flg = TTY_NORMAL;
1534
1535 /*
1536 * note that the error handling code is
1537 * out of the main execution path
1538 */
1539 if (unlikely(status & (ATMEL_US_PARE | ATMEL_US_FRAME
1540 | ATMEL_US_OVRE | ATMEL_US_RXBRK))) {
1541 if (status & ATMEL_US_RXBRK) {
1542 /* ignore side-effect */
1543 status &= ~(ATMEL_US_PARE | ATMEL_US_FRAME);
1544
1545 port->icount.brk++;
1546 if (uart_handle_break(port))
1547 continue;
1548 }
1549 if (status & ATMEL_US_PARE)
1550 port->icount.parity++;
1551 if (status & ATMEL_US_FRAME)
1552 port->icount.frame++;
1553 if (status & ATMEL_US_OVRE)
1554 port->icount.overrun++;
1555
1556 status &= port->read_status_mask;
1557
1558 if (status & ATMEL_US_RXBRK)
1559 flg = TTY_BREAK;
1560 else if (status & ATMEL_US_PARE)
1561 flg = TTY_PARITY;
1562 else if (status & ATMEL_US_FRAME)
1563 flg = TTY_FRAME;
1564 }
1565
1566
1567 if (uart_handle_sysrq_char(port, c.ch))
1568 continue;
1569
1570 uart_insert_char(port, status, ATMEL_US_OVRE, c.ch, flg);
1571 }
1572
1573 tty_flip_buffer_push(&port->state->port);
1574 }
1575
atmel_release_rx_pdc(struct uart_port * port)1576 static void atmel_release_rx_pdc(struct uart_port *port)
1577 {
1578 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1579 int i;
1580
1581 for (i = 0; i < 2; i++) {
1582 struct atmel_dma_buffer *pdc = &atmel_port->pdc_rx[i];
1583
1584 dma_unmap_single(port->dev,
1585 pdc->dma_addr,
1586 pdc->dma_size,
1587 DMA_FROM_DEVICE);
1588 kfree(pdc->buf);
1589 }
1590 }
1591
atmel_rx_from_pdc(struct uart_port * port)1592 static void atmel_rx_from_pdc(struct uart_port *port)
1593 {
1594 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1595 struct tty_port *tport = &port->state->port;
1596 struct atmel_dma_buffer *pdc;
1597 int rx_idx = atmel_port->pdc_rx_idx;
1598 unsigned int head;
1599 unsigned int tail;
1600 unsigned int count;
1601
1602 do {
1603 /* Reset the UART timeout early so that we don't miss one */
1604 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STTTO);
1605
1606 pdc = &atmel_port->pdc_rx[rx_idx];
1607 head = atmel_uart_readl(port, ATMEL_PDC_RPR) - pdc->dma_addr;
1608 tail = pdc->ofs;
1609
1610 /* If the PDC has switched buffers, RPR won't contain
1611 * any address within the current buffer. Since head
1612 * is unsigned, we just need a one-way comparison to
1613 * find out.
1614 *
1615 * In this case, we just need to consume the entire
1616 * buffer and resubmit it for DMA. This will clear the
1617 * ENDRX bit as well, so that we can safely re-enable
1618 * all interrupts below.
1619 */
1620 head = min(head, pdc->dma_size);
1621
1622 if (likely(head != tail)) {
1623 dma_sync_single_for_cpu(port->dev, pdc->dma_addr,
1624 pdc->dma_size, DMA_FROM_DEVICE);
1625
1626 /*
1627 * head will only wrap around when we recycle
1628 * the DMA buffer, and when that happens, we
1629 * explicitly set tail to 0. So head will
1630 * always be greater than tail.
1631 */
1632 count = head - tail;
1633
1634 tty_insert_flip_string(tport, pdc->buf + pdc->ofs,
1635 count);
1636
1637 dma_sync_single_for_device(port->dev, pdc->dma_addr,
1638 pdc->dma_size, DMA_FROM_DEVICE);
1639
1640 port->icount.rx += count;
1641 pdc->ofs = head;
1642 }
1643
1644 /*
1645 * If the current buffer is full, we need to check if
1646 * the next one contains any additional data.
1647 */
1648 if (head >= pdc->dma_size) {
1649 pdc->ofs = 0;
1650 atmel_uart_writel(port, ATMEL_PDC_RNPR, pdc->dma_addr);
1651 atmel_uart_writel(port, ATMEL_PDC_RNCR, pdc->dma_size);
1652
1653 rx_idx = !rx_idx;
1654 atmel_port->pdc_rx_idx = rx_idx;
1655 }
1656 } while (head >= pdc->dma_size);
1657
1658 tty_flip_buffer_push(tport);
1659
1660 atmel_uart_writel(port, ATMEL_US_IER,
1661 ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);
1662 }
1663
atmel_prepare_rx_pdc(struct uart_port * port)1664 static int atmel_prepare_rx_pdc(struct uart_port *port)
1665 {
1666 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1667 int i;
1668
1669 for (i = 0; i < 2; i++) {
1670 struct atmel_dma_buffer *pdc = &atmel_port->pdc_rx[i];
1671
1672 pdc->buf = kmalloc(PDC_BUFFER_SIZE, GFP_KERNEL);
1673 if (pdc->buf == NULL) {
1674 if (i != 0) {
1675 dma_unmap_single(port->dev,
1676 atmel_port->pdc_rx[0].dma_addr,
1677 PDC_BUFFER_SIZE,
1678 DMA_FROM_DEVICE);
1679 kfree(atmel_port->pdc_rx[0].buf);
1680 }
1681 atmel_port->use_pdc_rx = false;
1682 return -ENOMEM;
1683 }
1684 pdc->dma_addr = dma_map_single(port->dev,
1685 pdc->buf,
1686 PDC_BUFFER_SIZE,
1687 DMA_FROM_DEVICE);
1688 pdc->dma_size = PDC_BUFFER_SIZE;
1689 pdc->ofs = 0;
1690 }
1691
1692 atmel_port->pdc_rx_idx = 0;
1693
1694 atmel_uart_writel(port, ATMEL_PDC_RPR, atmel_port->pdc_rx[0].dma_addr);
1695 atmel_uart_writel(port, ATMEL_PDC_RCR, PDC_BUFFER_SIZE);
1696
1697 atmel_uart_writel(port, ATMEL_PDC_RNPR,
1698 atmel_port->pdc_rx[1].dma_addr);
1699 atmel_uart_writel(port, ATMEL_PDC_RNCR, PDC_BUFFER_SIZE);
1700
1701 return 0;
1702 }
1703
1704 /*
1705 * tasklet handling tty stuff outside the interrupt handler.
1706 */
atmel_tasklet_rx_func(struct tasklet_struct * t)1707 static void atmel_tasklet_rx_func(struct tasklet_struct *t)
1708 {
1709 struct atmel_uart_port *atmel_port = from_tasklet(atmel_port, t,
1710 tasklet_rx);
1711 struct uart_port *port = &atmel_port->uart;
1712
1713 /* The interrupt handler does not take the lock */
1714 spin_lock(&port->lock);
1715 atmel_port->schedule_rx(port);
1716 spin_unlock(&port->lock);
1717 }
1718
atmel_tasklet_tx_func(struct tasklet_struct * t)1719 static void atmel_tasklet_tx_func(struct tasklet_struct *t)
1720 {
1721 struct atmel_uart_port *atmel_port = from_tasklet(atmel_port, t,
1722 tasklet_tx);
1723 struct uart_port *port = &atmel_port->uart;
1724
1725 /* The interrupt handler does not take the lock */
1726 spin_lock(&port->lock);
1727 atmel_port->schedule_tx(port);
1728 spin_unlock(&port->lock);
1729 }
1730
atmel_init_property(struct atmel_uart_port * atmel_port,struct platform_device * pdev)1731 static void atmel_init_property(struct atmel_uart_port *atmel_port,
1732 struct platform_device *pdev)
1733 {
1734 struct device_node *np = pdev->dev.of_node;
1735
1736 /* DMA/PDC usage specification */
1737 if (of_property_read_bool(np, "atmel,use-dma-rx")) {
1738 if (of_property_read_bool(np, "dmas")) {
1739 atmel_port->use_dma_rx = true;
1740 atmel_port->use_pdc_rx = false;
1741 } else {
1742 atmel_port->use_dma_rx = false;
1743 atmel_port->use_pdc_rx = true;
1744 }
1745 } else {
1746 atmel_port->use_dma_rx = false;
1747 atmel_port->use_pdc_rx = false;
1748 }
1749
1750 if (of_property_read_bool(np, "atmel,use-dma-tx")) {
1751 if (of_property_read_bool(np, "dmas")) {
1752 atmel_port->use_dma_tx = true;
1753 atmel_port->use_pdc_tx = false;
1754 } else {
1755 atmel_port->use_dma_tx = false;
1756 atmel_port->use_pdc_tx = true;
1757 }
1758 } else {
1759 atmel_port->use_dma_tx = false;
1760 atmel_port->use_pdc_tx = false;
1761 }
1762 }
1763
atmel_set_ops(struct uart_port * port)1764 static void atmel_set_ops(struct uart_port *port)
1765 {
1766 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1767
1768 if (atmel_use_dma_rx(port)) {
1769 atmel_port->prepare_rx = &atmel_prepare_rx_dma;
1770 atmel_port->schedule_rx = &atmel_rx_from_dma;
1771 atmel_port->release_rx = &atmel_release_rx_dma;
1772 } else if (atmel_use_pdc_rx(port)) {
1773 atmel_port->prepare_rx = &atmel_prepare_rx_pdc;
1774 atmel_port->schedule_rx = &atmel_rx_from_pdc;
1775 atmel_port->release_rx = &atmel_release_rx_pdc;
1776 } else {
1777 atmel_port->prepare_rx = NULL;
1778 atmel_port->schedule_rx = &atmel_rx_from_ring;
1779 atmel_port->release_rx = NULL;
1780 }
1781
1782 if (atmel_use_dma_tx(port)) {
1783 atmel_port->prepare_tx = &atmel_prepare_tx_dma;
1784 atmel_port->schedule_tx = &atmel_tx_dma;
1785 atmel_port->release_tx = &atmel_release_tx_dma;
1786 } else if (atmel_use_pdc_tx(port)) {
1787 atmel_port->prepare_tx = &atmel_prepare_tx_pdc;
1788 atmel_port->schedule_tx = &atmel_tx_pdc;
1789 atmel_port->release_tx = &atmel_release_tx_pdc;
1790 } else {
1791 atmel_port->prepare_tx = NULL;
1792 atmel_port->schedule_tx = &atmel_tx_chars;
1793 atmel_port->release_tx = NULL;
1794 }
1795 }
1796
1797 /*
1798 * Get ip name usart or uart
1799 */
atmel_get_ip_name(struct uart_port * port)1800 static void atmel_get_ip_name(struct uart_port *port)
1801 {
1802 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1803 int name = atmel_uart_readl(port, ATMEL_US_NAME);
1804 u32 version;
1805 u32 usart, dbgu_uart, new_uart;
1806 /* ASCII decoding for IP version */
1807 usart = 0x55534152; /* USAR(T) */
1808 dbgu_uart = 0x44424755; /* DBGU */
1809 new_uart = 0x55415254; /* UART */
1810
1811 /*
1812 * Only USART devices from at91sam9260 SOC implement fractional
1813 * baudrate. It is available for all asynchronous modes, with the
1814 * following restriction: the sampling clock's duty cycle is not
1815 * constant.
1816 */
1817 atmel_port->has_frac_baudrate = false;
1818 atmel_port->has_hw_timer = false;
1819 atmel_port->is_usart = false;
1820
1821 if (name == new_uart) {
1822 dev_dbg(port->dev, "Uart with hw timer");
1823 atmel_port->has_hw_timer = true;
1824 atmel_port->rtor = ATMEL_UA_RTOR;
1825 } else if (name == usart) {
1826 dev_dbg(port->dev, "Usart\n");
1827 atmel_port->has_frac_baudrate = true;
1828 atmel_port->has_hw_timer = true;
1829 atmel_port->is_usart = true;
1830 atmel_port->rtor = ATMEL_US_RTOR;
1831 version = atmel_uart_readl(port, ATMEL_US_VERSION);
1832 switch (version) {
1833 case 0x814: /* sama5d2 */
1834 fallthrough;
1835 case 0x701: /* sama5d4 */
1836 atmel_port->fidi_min = 3;
1837 atmel_port->fidi_max = 65535;
1838 break;
1839 case 0x502: /* sam9x5, sama5d3 */
1840 atmel_port->fidi_min = 3;
1841 atmel_port->fidi_max = 2047;
1842 break;
1843 default:
1844 atmel_port->fidi_min = 1;
1845 atmel_port->fidi_max = 2047;
1846 }
1847 } else if (name == dbgu_uart) {
1848 dev_dbg(port->dev, "Dbgu or uart without hw timer\n");
1849 } else {
1850 /* fallback for older SoCs: use version field */
1851 version = atmel_uart_readl(port, ATMEL_US_VERSION);
1852 switch (version) {
1853 case 0x302:
1854 case 0x10213:
1855 case 0x10302:
1856 dev_dbg(port->dev, "This version is usart\n");
1857 atmel_port->has_frac_baudrate = true;
1858 atmel_port->has_hw_timer = true;
1859 atmel_port->is_usart = true;
1860 atmel_port->rtor = ATMEL_US_RTOR;
1861 break;
1862 case 0x203:
1863 case 0x10202:
1864 dev_dbg(port->dev, "This version is uart\n");
1865 break;
1866 default:
1867 dev_err(port->dev, "Not supported ip name nor version, set to uart\n");
1868 }
1869 }
1870 }
1871
1872 /*
1873 * Perform initialization and enable port for reception
1874 */
atmel_startup(struct uart_port * port)1875 static int atmel_startup(struct uart_port *port)
1876 {
1877 struct platform_device *pdev = to_platform_device(port->dev);
1878 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1879 int retval;
1880
1881 /*
1882 * Ensure that no interrupts are enabled otherwise when
1883 * request_irq() is called we could get stuck trying to
1884 * handle an unexpected interrupt
1885 */
1886 atmel_uart_writel(port, ATMEL_US_IDR, -1);
1887 atmel_port->ms_irq_enabled = false;
1888
1889 /*
1890 * Allocate the IRQ
1891 */
1892 retval = request_irq(port->irq, atmel_interrupt,
1893 IRQF_SHARED | IRQF_COND_SUSPEND,
1894 dev_name(&pdev->dev), port);
1895 if (retval) {
1896 dev_err(port->dev, "atmel_startup - Can't get irq\n");
1897 return retval;
1898 }
1899
1900 atomic_set(&atmel_port->tasklet_shutdown, 0);
1901 tasklet_setup(&atmel_port->tasklet_rx, atmel_tasklet_rx_func);
1902 tasklet_setup(&atmel_port->tasklet_tx, atmel_tasklet_tx_func);
1903
1904 /*
1905 * Initialize DMA (if necessary)
1906 */
1907 atmel_init_property(atmel_port, pdev);
1908 atmel_set_ops(port);
1909
1910 if (atmel_port->prepare_rx) {
1911 retval = atmel_port->prepare_rx(port);
1912 if (retval < 0)
1913 atmel_set_ops(port);
1914 }
1915
1916 if (atmel_port->prepare_tx) {
1917 retval = atmel_port->prepare_tx(port);
1918 if (retval < 0)
1919 atmel_set_ops(port);
1920 }
1921
1922 /*
1923 * Enable FIFO when available
1924 */
1925 if (atmel_port->fifo_size) {
1926 unsigned int txrdym = ATMEL_US_ONE_DATA;
1927 unsigned int rxrdym = ATMEL_US_ONE_DATA;
1928 unsigned int fmr;
1929
1930 atmel_uart_writel(port, ATMEL_US_CR,
1931 ATMEL_US_FIFOEN |
1932 ATMEL_US_RXFCLR |
1933 ATMEL_US_TXFLCLR);
1934
1935 if (atmel_use_dma_tx(port))
1936 txrdym = ATMEL_US_FOUR_DATA;
1937
1938 fmr = ATMEL_US_TXRDYM(txrdym) | ATMEL_US_RXRDYM(rxrdym);
1939 if (atmel_port->rts_high &&
1940 atmel_port->rts_low)
1941 fmr |= ATMEL_US_FRTSC |
1942 ATMEL_US_RXFTHRES(atmel_port->rts_high) |
1943 ATMEL_US_RXFTHRES2(atmel_port->rts_low);
1944
1945 atmel_uart_writel(port, ATMEL_US_FMR, fmr);
1946 }
1947
1948 /* Save current CSR for comparison in atmel_tasklet_func() */
1949 atmel_port->irq_status_prev = atmel_uart_readl(port, ATMEL_US_CSR);
1950
1951 /*
1952 * Finally, enable the serial port
1953 */
1954 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
1955 /* enable xmit & rcvr */
1956 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN);
1957 atmel_port->tx_stopped = false;
1958
1959 timer_setup(&atmel_port->uart_timer, atmel_uart_timer_callback, 0);
1960
1961 if (atmel_use_pdc_rx(port)) {
1962 /* set UART timeout */
1963 if (!atmel_port->has_hw_timer) {
1964 mod_timer(&atmel_port->uart_timer,
1965 jiffies + uart_poll_timeout(port));
1966 /* set USART timeout */
1967 } else {
1968 atmel_uart_writel(port, atmel_port->rtor,
1969 PDC_RX_TIMEOUT);
1970 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STTTO);
1971
1972 atmel_uart_writel(port, ATMEL_US_IER,
1973 ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);
1974 }
1975 /* enable PDC controller */
1976 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_RXTEN);
1977 } else if (atmel_use_dma_rx(port)) {
1978 /* set UART timeout */
1979 if (!atmel_port->has_hw_timer) {
1980 mod_timer(&atmel_port->uart_timer,
1981 jiffies + uart_poll_timeout(port));
1982 /* set USART timeout */
1983 } else {
1984 atmel_uart_writel(port, atmel_port->rtor,
1985 PDC_RX_TIMEOUT);
1986 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STTTO);
1987
1988 atmel_uart_writel(port, ATMEL_US_IER,
1989 ATMEL_US_TIMEOUT);
1990 }
1991 } else {
1992 /* enable receive only */
1993 atmel_uart_writel(port, ATMEL_US_IER, ATMEL_US_RXRDY);
1994 }
1995
1996 return 0;
1997 }
1998
1999 /*
2000 * Flush any TX data submitted for DMA. Called when the TX circular
2001 * buffer is reset.
2002 */
atmel_flush_buffer(struct uart_port * port)2003 static void atmel_flush_buffer(struct uart_port *port)
2004 {
2005 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2006
2007 if (atmel_use_pdc_tx(port)) {
2008 atmel_uart_writel(port, ATMEL_PDC_TCR, 0);
2009 atmel_port->pdc_tx.ofs = 0;
2010 }
2011 /*
2012 * in uart_flush_buffer(), the xmit circular buffer has just
2013 * been cleared, so we have to reset tx_len accordingly.
2014 */
2015 atmel_port->tx_len = 0;
2016 }
2017
2018 /*
2019 * Disable the port
2020 */
atmel_shutdown(struct uart_port * port)2021 static void atmel_shutdown(struct uart_port *port)
2022 {
2023 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2024
2025 /* Disable modem control lines interrupts */
2026 atmel_disable_ms(port);
2027
2028 /* Disable interrupts at device level */
2029 atmel_uart_writel(port, ATMEL_US_IDR, -1);
2030
2031 /* Prevent spurious interrupts from scheduling the tasklet */
2032 atomic_inc(&atmel_port->tasklet_shutdown);
2033
2034 /*
2035 * Prevent any tasklets being scheduled during
2036 * cleanup
2037 */
2038 del_timer_sync(&atmel_port->uart_timer);
2039
2040 /* Make sure that no interrupt is on the fly */
2041 synchronize_irq(port->irq);
2042
2043 /*
2044 * Clear out any scheduled tasklets before
2045 * we destroy the buffers
2046 */
2047 tasklet_kill(&atmel_port->tasklet_rx);
2048 tasklet_kill(&atmel_port->tasklet_tx);
2049
2050 /*
2051 * Ensure everything is stopped and
2052 * disable port and break condition.
2053 */
2054 atmel_stop_rx(port);
2055 atmel_stop_tx(port);
2056
2057 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA);
2058
2059 /*
2060 * Shut-down the DMA.
2061 */
2062 if (atmel_port->release_rx)
2063 atmel_port->release_rx(port);
2064 if (atmel_port->release_tx)
2065 atmel_port->release_tx(port);
2066
2067 /*
2068 * Reset ring buffer pointers
2069 */
2070 atmel_port->rx_ring.head = 0;
2071 atmel_port->rx_ring.tail = 0;
2072
2073 /*
2074 * Free the interrupts
2075 */
2076 free_irq(port->irq, port);
2077
2078 atmel_flush_buffer(port);
2079 }
2080
2081 /*
2082 * Power / Clock management.
2083 */
atmel_serial_pm(struct uart_port * port,unsigned int state,unsigned int oldstate)2084 static void atmel_serial_pm(struct uart_port *port, unsigned int state,
2085 unsigned int oldstate)
2086 {
2087 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2088
2089 switch (state) {
2090 case UART_PM_STATE_ON:
2091 /*
2092 * Enable the peripheral clock for this serial port.
2093 * This is called on uart_open() or a resume event.
2094 */
2095 clk_prepare_enable(atmel_port->clk);
2096
2097 /* re-enable interrupts if we disabled some on suspend */
2098 atmel_uart_writel(port, ATMEL_US_IER, atmel_port->backup_imr);
2099 break;
2100 case UART_PM_STATE_OFF:
2101 /* Back up the interrupt mask and disable all interrupts */
2102 atmel_port->backup_imr = atmel_uart_readl(port, ATMEL_US_IMR);
2103 atmel_uart_writel(port, ATMEL_US_IDR, -1);
2104
2105 /*
2106 * Disable the peripheral clock for this serial port.
2107 * This is called on uart_close() or a suspend event.
2108 */
2109 clk_disable_unprepare(atmel_port->clk);
2110 if (__clk_is_enabled(atmel_port->gclk))
2111 clk_disable_unprepare(atmel_port->gclk);
2112 break;
2113 default:
2114 dev_err(port->dev, "atmel_serial: unknown pm %d\n", state);
2115 }
2116 }
2117
2118 /*
2119 * Change the port parameters
2120 */
atmel_set_termios(struct uart_port * port,struct ktermios * termios,const struct ktermios * old)2121 static void atmel_set_termios(struct uart_port *port,
2122 struct ktermios *termios,
2123 const struct ktermios *old)
2124 {
2125 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2126 unsigned long flags;
2127 unsigned int old_mode, mode, imr, quot, div, cd, fp = 0;
2128 unsigned int baud, actual_baud, gclk_rate;
2129 int ret;
2130
2131 /* save the current mode register */
2132 mode = old_mode = atmel_uart_readl(port, ATMEL_US_MR);
2133
2134 /* reset the mode, clock divisor, parity, stop bits and data size */
2135 if (atmel_port->is_usart)
2136 mode &= ~(ATMEL_US_NBSTOP | ATMEL_US_PAR | ATMEL_US_CHRL |
2137 ATMEL_US_USCLKS | ATMEL_US_USMODE);
2138 else
2139 mode &= ~(ATMEL_UA_BRSRCCK | ATMEL_US_PAR | ATMEL_UA_FILTER);
2140
2141 baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
2142
2143 /* byte size */
2144 switch (termios->c_cflag & CSIZE) {
2145 case CS5:
2146 mode |= ATMEL_US_CHRL_5;
2147 break;
2148 case CS6:
2149 mode |= ATMEL_US_CHRL_6;
2150 break;
2151 case CS7:
2152 mode |= ATMEL_US_CHRL_7;
2153 break;
2154 default:
2155 mode |= ATMEL_US_CHRL_8;
2156 break;
2157 }
2158
2159 /* stop bits */
2160 if (termios->c_cflag & CSTOPB)
2161 mode |= ATMEL_US_NBSTOP_2;
2162
2163 /* parity */
2164 if (termios->c_cflag & PARENB) {
2165 /* Mark or Space parity */
2166 if (termios->c_cflag & CMSPAR) {
2167 if (termios->c_cflag & PARODD)
2168 mode |= ATMEL_US_PAR_MARK;
2169 else
2170 mode |= ATMEL_US_PAR_SPACE;
2171 } else if (termios->c_cflag & PARODD)
2172 mode |= ATMEL_US_PAR_ODD;
2173 else
2174 mode |= ATMEL_US_PAR_EVEN;
2175 } else
2176 mode |= ATMEL_US_PAR_NONE;
2177
2178 spin_lock_irqsave(&port->lock, flags);
2179
2180 port->read_status_mask = ATMEL_US_OVRE;
2181 if (termios->c_iflag & INPCK)
2182 port->read_status_mask |= (ATMEL_US_FRAME | ATMEL_US_PARE);
2183 if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
2184 port->read_status_mask |= ATMEL_US_RXBRK;
2185
2186 if (atmel_use_pdc_rx(port))
2187 /* need to enable error interrupts */
2188 atmel_uart_writel(port, ATMEL_US_IER, port->read_status_mask);
2189
2190 /*
2191 * Characters to ignore
2192 */
2193 port->ignore_status_mask = 0;
2194 if (termios->c_iflag & IGNPAR)
2195 port->ignore_status_mask |= (ATMEL_US_FRAME | ATMEL_US_PARE);
2196 if (termios->c_iflag & IGNBRK) {
2197 port->ignore_status_mask |= ATMEL_US_RXBRK;
2198 /*
2199 * If we're ignoring parity and break indicators,
2200 * ignore overruns too (for real raw support).
2201 */
2202 if (termios->c_iflag & IGNPAR)
2203 port->ignore_status_mask |= ATMEL_US_OVRE;
2204 }
2205 /* TODO: Ignore all characters if CREAD is set.*/
2206
2207 /* update the per-port timeout */
2208 uart_update_timeout(port, termios->c_cflag, baud);
2209
2210 /*
2211 * save/disable interrupts. The tty layer will ensure that the
2212 * transmitter is empty if requested by the caller, so there's
2213 * no need to wait for it here.
2214 */
2215 imr = atmel_uart_readl(port, ATMEL_US_IMR);
2216 atmel_uart_writel(port, ATMEL_US_IDR, -1);
2217
2218 /* disable receiver and transmitter */
2219 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXDIS | ATMEL_US_RXDIS);
2220 atmel_port->tx_stopped = true;
2221
2222 /* mode */
2223 if (port->rs485.flags & SER_RS485_ENABLED) {
2224 atmel_uart_writel(port, ATMEL_US_TTGR,
2225 port->rs485.delay_rts_after_send);
2226 mode |= ATMEL_US_USMODE_RS485;
2227 } else if (port->iso7816.flags & SER_ISO7816_ENABLED) {
2228 atmel_uart_writel(port, ATMEL_US_TTGR, port->iso7816.tg);
2229 /* select mck clock, and output */
2230 mode |= ATMEL_US_USCLKS_MCK | ATMEL_US_CLKO;
2231 /* set max iterations */
2232 mode |= ATMEL_US_MAX_ITER(3);
2233 if ((port->iso7816.flags & SER_ISO7816_T_PARAM)
2234 == SER_ISO7816_T(0))
2235 mode |= ATMEL_US_USMODE_ISO7816_T0;
2236 else
2237 mode |= ATMEL_US_USMODE_ISO7816_T1;
2238 } else if (termios->c_cflag & CRTSCTS) {
2239 /* RS232 with hardware handshake (RTS/CTS) */
2240 if (atmel_use_fifo(port) &&
2241 !mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS)) {
2242 /*
2243 * with ATMEL_US_USMODE_HWHS set, the controller will
2244 * be able to drive the RTS pin high/low when the RX
2245 * FIFO is above RXFTHRES/below RXFTHRES2.
2246 * It will also disable the transmitter when the CTS
2247 * pin is high.
2248 * This mode is not activated if CTS pin is a GPIO
2249 * because in this case, the transmitter is always
2250 * disabled (there must be an internal pull-up
2251 * responsible for this behaviour).
2252 * If the RTS pin is a GPIO, the controller won't be
2253 * able to drive it according to the FIFO thresholds,
2254 * but it will be handled by the driver.
2255 */
2256 mode |= ATMEL_US_USMODE_HWHS;
2257 } else {
2258 /*
2259 * For platforms without FIFO, the flow control is
2260 * handled by the driver.
2261 */
2262 mode |= ATMEL_US_USMODE_NORMAL;
2263 }
2264 } else {
2265 /* RS232 without hadware handshake */
2266 mode |= ATMEL_US_USMODE_NORMAL;
2267 }
2268
2269 /*
2270 * Set the baud rate:
2271 * Fractional baudrate allows to setup output frequency more
2272 * accurately. This feature is enabled only when using normal mode.
2273 * baudrate = selected clock / (8 * (2 - OVER) * (CD + FP / 8))
2274 * Currently, OVER is always set to 0 so we get
2275 * baudrate = selected clock / (16 * (CD + FP / 8))
2276 * then
2277 * 8 CD + FP = selected clock / (2 * baudrate)
2278 */
2279 if (atmel_port->has_frac_baudrate) {
2280 div = DIV_ROUND_CLOSEST(port->uartclk, baud * 2);
2281 cd = div >> 3;
2282 fp = div & ATMEL_US_FP_MASK;
2283 } else {
2284 cd = uart_get_divisor(port, baud);
2285 }
2286
2287 /*
2288 * If the current value of the Clock Divisor surpasses the 16 bit
2289 * ATMEL_US_CD mask and the IP is USART, switch to the Peripheral
2290 * Clock implicitly divided by 8.
2291 * If the IP is UART however, keep the highest possible value for
2292 * the CD and avoid needless division of CD, since UART IP's do not
2293 * support implicit division of the Peripheral Clock.
2294 */
2295 if (atmel_port->is_usart && cd > ATMEL_US_CD) {
2296 cd /= 8;
2297 mode |= ATMEL_US_USCLKS_MCK_DIV8;
2298 } else {
2299 cd = min_t(unsigned int, cd, ATMEL_US_CD);
2300 }
2301
2302 /*
2303 * If there is no Fractional Part, there is a high chance that
2304 * we may be able to generate a baudrate closer to the desired one
2305 * if we use the GCLK as the clock source driving the baudrate
2306 * generator.
2307 */
2308 if (!atmel_port->has_frac_baudrate) {
2309 if (__clk_is_enabled(atmel_port->gclk))
2310 clk_disable_unprepare(atmel_port->gclk);
2311 gclk_rate = clk_round_rate(atmel_port->gclk, 16 * baud);
2312 actual_baud = clk_get_rate(atmel_port->clk) / (16 * cd);
2313 if (gclk_rate && abs(atmel_error_rate(baud, actual_baud)) >
2314 abs(atmel_error_rate(baud, gclk_rate / 16))) {
2315 clk_set_rate(atmel_port->gclk, 16 * baud);
2316 ret = clk_prepare_enable(atmel_port->gclk);
2317 if (ret)
2318 goto gclk_fail;
2319
2320 if (atmel_port->is_usart) {
2321 mode &= ~ATMEL_US_USCLKS;
2322 mode |= ATMEL_US_USCLKS_GCLK;
2323 } else {
2324 mode |= ATMEL_UA_BRSRCCK;
2325 }
2326
2327 /*
2328 * Set the Clock Divisor for GCLK to 1.
2329 * Since we were able to generate the smallest
2330 * multiple of the desired baudrate times 16,
2331 * then we surely can generate a bigger multiple
2332 * with the exact error rate for an equally increased
2333 * CD. Thus no need to take into account
2334 * a higher value for CD.
2335 */
2336 cd = 1;
2337 }
2338 }
2339
2340 gclk_fail:
2341 quot = cd | fp << ATMEL_US_FP_OFFSET;
2342
2343 if (!(port->iso7816.flags & SER_ISO7816_ENABLED))
2344 atmel_uart_writel(port, ATMEL_US_BRGR, quot);
2345
2346 /* set the mode, clock divisor, parity, stop bits and data size */
2347 atmel_uart_writel(port, ATMEL_US_MR, mode);
2348
2349 /*
2350 * when switching the mode, set the RTS line state according to the
2351 * new mode, otherwise keep the former state
2352 */
2353 if ((old_mode & ATMEL_US_USMODE) != (mode & ATMEL_US_USMODE)) {
2354 unsigned int rts_state;
2355
2356 if ((mode & ATMEL_US_USMODE) == ATMEL_US_USMODE_HWHS) {
2357 /* let the hardware control the RTS line */
2358 rts_state = ATMEL_US_RTSDIS;
2359 } else {
2360 /* force RTS line to low level */
2361 rts_state = ATMEL_US_RTSEN;
2362 }
2363
2364 atmel_uart_writel(port, ATMEL_US_CR, rts_state);
2365 }
2366
2367 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
2368 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN);
2369 atmel_port->tx_stopped = false;
2370
2371 /* restore interrupts */
2372 atmel_uart_writel(port, ATMEL_US_IER, imr);
2373
2374 /* CTS flow-control and modem-status interrupts */
2375 if (UART_ENABLE_MS(port, termios->c_cflag))
2376 atmel_enable_ms(port);
2377 else
2378 atmel_disable_ms(port);
2379
2380 spin_unlock_irqrestore(&port->lock, flags);
2381 }
2382
atmel_set_ldisc(struct uart_port * port,struct ktermios * termios)2383 static void atmel_set_ldisc(struct uart_port *port, struct ktermios *termios)
2384 {
2385 if (termios->c_line == N_PPS) {
2386 port->flags |= UPF_HARDPPS_CD;
2387 spin_lock_irq(&port->lock);
2388 atmel_enable_ms(port);
2389 spin_unlock_irq(&port->lock);
2390 } else {
2391 port->flags &= ~UPF_HARDPPS_CD;
2392 if (!UART_ENABLE_MS(port, termios->c_cflag)) {
2393 spin_lock_irq(&port->lock);
2394 atmel_disable_ms(port);
2395 spin_unlock_irq(&port->lock);
2396 }
2397 }
2398 }
2399
2400 /*
2401 * Return string describing the specified port
2402 */
atmel_type(struct uart_port * port)2403 static const char *atmel_type(struct uart_port *port)
2404 {
2405 return (port->type == PORT_ATMEL) ? "ATMEL_SERIAL" : NULL;
2406 }
2407
2408 /*
2409 * Release the memory region(s) being used by 'port'.
2410 */
atmel_release_port(struct uart_port * port)2411 static void atmel_release_port(struct uart_port *port)
2412 {
2413 struct platform_device *mpdev = to_platform_device(port->dev->parent);
2414 int size = resource_size(mpdev->resource);
2415
2416 release_mem_region(port->mapbase, size);
2417
2418 if (port->flags & UPF_IOREMAP) {
2419 iounmap(port->membase);
2420 port->membase = NULL;
2421 }
2422 }
2423
2424 /*
2425 * Request the memory region(s) being used by 'port'.
2426 */
atmel_request_port(struct uart_port * port)2427 static int atmel_request_port(struct uart_port *port)
2428 {
2429 struct platform_device *mpdev = to_platform_device(port->dev->parent);
2430 int size = resource_size(mpdev->resource);
2431
2432 if (!request_mem_region(port->mapbase, size, "atmel_serial"))
2433 return -EBUSY;
2434
2435 if (port->flags & UPF_IOREMAP) {
2436 port->membase = ioremap(port->mapbase, size);
2437 if (port->membase == NULL) {
2438 release_mem_region(port->mapbase, size);
2439 return -ENOMEM;
2440 }
2441 }
2442
2443 return 0;
2444 }
2445
2446 /*
2447 * Configure/autoconfigure the port.
2448 */
atmel_config_port(struct uart_port * port,int flags)2449 static void atmel_config_port(struct uart_port *port, int flags)
2450 {
2451 if (flags & UART_CONFIG_TYPE) {
2452 port->type = PORT_ATMEL;
2453 atmel_request_port(port);
2454 }
2455 }
2456
2457 /*
2458 * Verify the new serial_struct (for TIOCSSERIAL).
2459 */
atmel_verify_port(struct uart_port * port,struct serial_struct * ser)2460 static int atmel_verify_port(struct uart_port *port, struct serial_struct *ser)
2461 {
2462 int ret = 0;
2463 if (ser->type != PORT_UNKNOWN && ser->type != PORT_ATMEL)
2464 ret = -EINVAL;
2465 if (port->irq != ser->irq)
2466 ret = -EINVAL;
2467 if (ser->io_type != SERIAL_IO_MEM)
2468 ret = -EINVAL;
2469 if (port->uartclk / 16 != ser->baud_base)
2470 ret = -EINVAL;
2471 if (port->mapbase != (unsigned long)ser->iomem_base)
2472 ret = -EINVAL;
2473 if (port->iobase != ser->port)
2474 ret = -EINVAL;
2475 if (ser->hub6 != 0)
2476 ret = -EINVAL;
2477 return ret;
2478 }
2479
2480 #ifdef CONFIG_CONSOLE_POLL
atmel_poll_get_char(struct uart_port * port)2481 static int atmel_poll_get_char(struct uart_port *port)
2482 {
2483 while (!(atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_RXRDY))
2484 cpu_relax();
2485
2486 return atmel_uart_read_char(port);
2487 }
2488
atmel_poll_put_char(struct uart_port * port,unsigned char ch)2489 static void atmel_poll_put_char(struct uart_port *port, unsigned char ch)
2490 {
2491 while (!(atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXRDY))
2492 cpu_relax();
2493
2494 atmel_uart_write_char(port, ch);
2495 }
2496 #endif
2497
2498 static const struct uart_ops atmel_pops = {
2499 .tx_empty = atmel_tx_empty,
2500 .set_mctrl = atmel_set_mctrl,
2501 .get_mctrl = atmel_get_mctrl,
2502 .stop_tx = atmel_stop_tx,
2503 .start_tx = atmel_start_tx,
2504 .stop_rx = atmel_stop_rx,
2505 .enable_ms = atmel_enable_ms,
2506 .break_ctl = atmel_break_ctl,
2507 .startup = atmel_startup,
2508 .shutdown = atmel_shutdown,
2509 .flush_buffer = atmel_flush_buffer,
2510 .set_termios = atmel_set_termios,
2511 .set_ldisc = atmel_set_ldisc,
2512 .type = atmel_type,
2513 .release_port = atmel_release_port,
2514 .request_port = atmel_request_port,
2515 .config_port = atmel_config_port,
2516 .verify_port = atmel_verify_port,
2517 .pm = atmel_serial_pm,
2518 #ifdef CONFIG_CONSOLE_POLL
2519 .poll_get_char = atmel_poll_get_char,
2520 .poll_put_char = atmel_poll_put_char,
2521 #endif
2522 };
2523
2524 static const struct serial_rs485 atmel_rs485_supported = {
2525 .flags = SER_RS485_ENABLED | SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX,
2526 .delay_rts_before_send = 1,
2527 .delay_rts_after_send = 1,
2528 };
2529
2530 /*
2531 * Configure the port from the platform device resource info.
2532 */
atmel_init_port(struct atmel_uart_port * atmel_port,struct platform_device * pdev)2533 static int atmel_init_port(struct atmel_uart_port *atmel_port,
2534 struct platform_device *pdev)
2535 {
2536 int ret;
2537 struct uart_port *port = &atmel_port->uart;
2538 struct platform_device *mpdev = to_platform_device(pdev->dev.parent);
2539
2540 atmel_init_property(atmel_port, pdev);
2541 atmel_set_ops(port);
2542
2543 port->iotype = UPIO_MEM;
2544 port->flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP;
2545 port->ops = &atmel_pops;
2546 port->fifosize = 1;
2547 port->dev = &pdev->dev;
2548 port->mapbase = mpdev->resource[0].start;
2549 port->irq = platform_get_irq(mpdev, 0);
2550 port->rs485_config = atmel_config_rs485;
2551 port->rs485_supported = atmel_rs485_supported;
2552 port->iso7816_config = atmel_config_iso7816;
2553 port->membase = NULL;
2554
2555 memset(&atmel_port->rx_ring, 0, sizeof(atmel_port->rx_ring));
2556
2557 ret = uart_get_rs485_mode(port);
2558 if (ret)
2559 return ret;
2560
2561 port->uartclk = clk_get_rate(atmel_port->clk);
2562
2563 /*
2564 * Use TXEMPTY for interrupt when rs485 or ISO7816 else TXRDY or
2565 * ENDTX|TXBUFE
2566 */
2567 if (atmel_uart_is_half_duplex(port))
2568 atmel_port->tx_done_mask = ATMEL_US_TXEMPTY;
2569 else if (atmel_use_pdc_tx(port)) {
2570 port->fifosize = PDC_BUFFER_SIZE;
2571 atmel_port->tx_done_mask = ATMEL_US_ENDTX | ATMEL_US_TXBUFE;
2572 } else {
2573 atmel_port->tx_done_mask = ATMEL_US_TXRDY;
2574 }
2575
2576 return 0;
2577 }
2578
2579 #ifdef CONFIG_SERIAL_ATMEL_CONSOLE
atmel_console_putchar(struct uart_port * port,unsigned char ch)2580 static void atmel_console_putchar(struct uart_port *port, unsigned char ch)
2581 {
2582 while (!(atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXRDY))
2583 cpu_relax();
2584 atmel_uart_write_char(port, ch);
2585 }
2586
2587 /*
2588 * Interrupts are disabled on entering
2589 */
atmel_console_write(struct console * co,const char * s,u_int count)2590 static void atmel_console_write(struct console *co, const char *s, u_int count)
2591 {
2592 struct uart_port *port = &atmel_ports[co->index].uart;
2593 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2594 unsigned int status, imr;
2595 unsigned int pdc_tx;
2596
2597 /*
2598 * First, save IMR and then disable interrupts
2599 */
2600 imr = atmel_uart_readl(port, ATMEL_US_IMR);
2601 atmel_uart_writel(port, ATMEL_US_IDR,
2602 ATMEL_US_RXRDY | atmel_port->tx_done_mask);
2603
2604 /* Store PDC transmit status and disable it */
2605 pdc_tx = atmel_uart_readl(port, ATMEL_PDC_PTSR) & ATMEL_PDC_TXTEN;
2606 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTDIS);
2607
2608 /* Make sure that tx path is actually able to send characters */
2609 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN);
2610 atmel_port->tx_stopped = false;
2611
2612 uart_console_write(port, s, count, atmel_console_putchar);
2613
2614 /*
2615 * Finally, wait for transmitter to become empty
2616 * and restore IMR
2617 */
2618 do {
2619 status = atmel_uart_readl(port, ATMEL_US_CSR);
2620 } while (!(status & ATMEL_US_TXRDY));
2621
2622 /* Restore PDC transmit status */
2623 if (pdc_tx)
2624 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTEN);
2625
2626 /* set interrupts back the way they were */
2627 atmel_uart_writel(port, ATMEL_US_IER, imr);
2628 }
2629
2630 /*
2631 * If the port was already initialised (eg, by a boot loader),
2632 * try to determine the current setup.
2633 */
atmel_console_get_options(struct uart_port * port,int * baud,int * parity,int * bits)2634 static void __init atmel_console_get_options(struct uart_port *port, int *baud,
2635 int *parity, int *bits)
2636 {
2637 unsigned int mr, quot;
2638
2639 /*
2640 * If the baud rate generator isn't running, the port wasn't
2641 * initialized by the boot loader.
2642 */
2643 quot = atmel_uart_readl(port, ATMEL_US_BRGR) & ATMEL_US_CD;
2644 if (!quot)
2645 return;
2646
2647 mr = atmel_uart_readl(port, ATMEL_US_MR) & ATMEL_US_CHRL;
2648 if (mr == ATMEL_US_CHRL_8)
2649 *bits = 8;
2650 else
2651 *bits = 7;
2652
2653 mr = atmel_uart_readl(port, ATMEL_US_MR) & ATMEL_US_PAR;
2654 if (mr == ATMEL_US_PAR_EVEN)
2655 *parity = 'e';
2656 else if (mr == ATMEL_US_PAR_ODD)
2657 *parity = 'o';
2658
2659 *baud = port->uartclk / (16 * quot);
2660 }
2661
atmel_console_setup(struct console * co,char * options)2662 static int __init atmel_console_setup(struct console *co, char *options)
2663 {
2664 struct uart_port *port = &atmel_ports[co->index].uart;
2665 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2666 int baud = 115200;
2667 int bits = 8;
2668 int parity = 'n';
2669 int flow = 'n';
2670
2671 if (port->membase == NULL) {
2672 /* Port not initialized yet - delay setup */
2673 return -ENODEV;
2674 }
2675
2676 atmel_uart_writel(port, ATMEL_US_IDR, -1);
2677 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
2678 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN);
2679 atmel_port->tx_stopped = false;
2680
2681 if (options)
2682 uart_parse_options(options, &baud, &parity, &bits, &flow);
2683 else
2684 atmel_console_get_options(port, &baud, &parity, &bits);
2685
2686 return uart_set_options(port, co, baud, parity, bits, flow);
2687 }
2688
2689 static struct uart_driver atmel_uart;
2690
2691 static struct console atmel_console = {
2692 .name = ATMEL_DEVICENAME,
2693 .write = atmel_console_write,
2694 .device = uart_console_device,
2695 .setup = atmel_console_setup,
2696 .flags = CON_PRINTBUFFER,
2697 .index = -1,
2698 .data = &atmel_uart,
2699 };
2700
atmel_serial_early_write(struct console * con,const char * s,unsigned int n)2701 static void atmel_serial_early_write(struct console *con, const char *s,
2702 unsigned int n)
2703 {
2704 struct earlycon_device *dev = con->data;
2705
2706 uart_console_write(&dev->port, s, n, atmel_console_putchar);
2707 }
2708
atmel_early_console_setup(struct earlycon_device * device,const char * options)2709 static int __init atmel_early_console_setup(struct earlycon_device *device,
2710 const char *options)
2711 {
2712 if (!device->port.membase)
2713 return -ENODEV;
2714
2715 device->con->write = atmel_serial_early_write;
2716
2717 return 0;
2718 }
2719
2720 OF_EARLYCON_DECLARE(atmel_serial, "atmel,at91rm9200-usart",
2721 atmel_early_console_setup);
2722 OF_EARLYCON_DECLARE(atmel_serial, "atmel,at91sam9260-usart",
2723 atmel_early_console_setup);
2724
2725 #define ATMEL_CONSOLE_DEVICE (&atmel_console)
2726
2727 #else
2728 #define ATMEL_CONSOLE_DEVICE NULL
2729 #endif
2730
2731 static struct uart_driver atmel_uart = {
2732 .owner = THIS_MODULE,
2733 .driver_name = "atmel_serial",
2734 .dev_name = ATMEL_DEVICENAME,
2735 .major = SERIAL_ATMEL_MAJOR,
2736 .minor = MINOR_START,
2737 .nr = ATMEL_MAX_UART,
2738 .cons = ATMEL_CONSOLE_DEVICE,
2739 };
2740
atmel_serial_clk_will_stop(void)2741 static bool atmel_serial_clk_will_stop(void)
2742 {
2743 #ifdef CONFIG_ARCH_AT91
2744 return at91_suspend_entering_slow_clock();
2745 #else
2746 return false;
2747 #endif
2748 }
2749
atmel_serial_suspend(struct device * dev)2750 static int __maybe_unused atmel_serial_suspend(struct device *dev)
2751 {
2752 struct uart_port *port = dev_get_drvdata(dev);
2753 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2754
2755 if (uart_console(port) && console_suspend_enabled) {
2756 /* Drain the TX shifter */
2757 while (!(atmel_uart_readl(port, ATMEL_US_CSR) &
2758 ATMEL_US_TXEMPTY))
2759 cpu_relax();
2760 }
2761
2762 if (uart_console(port) && !console_suspend_enabled) {
2763 /* Cache register values as we won't get a full shutdown/startup
2764 * cycle
2765 */
2766 atmel_port->cache.mr = atmel_uart_readl(port, ATMEL_US_MR);
2767 atmel_port->cache.imr = atmel_uart_readl(port, ATMEL_US_IMR);
2768 atmel_port->cache.brgr = atmel_uart_readl(port, ATMEL_US_BRGR);
2769 atmel_port->cache.rtor = atmel_uart_readl(port,
2770 atmel_port->rtor);
2771 atmel_port->cache.ttgr = atmel_uart_readl(port, ATMEL_US_TTGR);
2772 atmel_port->cache.fmr = atmel_uart_readl(port, ATMEL_US_FMR);
2773 atmel_port->cache.fimr = atmel_uart_readl(port, ATMEL_US_FIMR);
2774 }
2775
2776 /* we can not wake up if we're running on slow clock */
2777 atmel_port->may_wakeup = device_may_wakeup(dev);
2778 if (atmel_serial_clk_will_stop()) {
2779 unsigned long flags;
2780
2781 spin_lock_irqsave(&atmel_port->lock_suspended, flags);
2782 atmel_port->suspended = true;
2783 spin_unlock_irqrestore(&atmel_port->lock_suspended, flags);
2784 device_set_wakeup_enable(dev, 0);
2785 }
2786
2787 uart_suspend_port(&atmel_uart, port);
2788
2789 return 0;
2790 }
2791
atmel_serial_resume(struct device * dev)2792 static int __maybe_unused atmel_serial_resume(struct device *dev)
2793 {
2794 struct uart_port *port = dev_get_drvdata(dev);
2795 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2796 unsigned long flags;
2797
2798 if (uart_console(port) && !console_suspend_enabled) {
2799 atmel_uart_writel(port, ATMEL_US_MR, atmel_port->cache.mr);
2800 atmel_uart_writel(port, ATMEL_US_IER, atmel_port->cache.imr);
2801 atmel_uart_writel(port, ATMEL_US_BRGR, atmel_port->cache.brgr);
2802 atmel_uart_writel(port, atmel_port->rtor,
2803 atmel_port->cache.rtor);
2804 atmel_uart_writel(port, ATMEL_US_TTGR, atmel_port->cache.ttgr);
2805
2806 if (atmel_port->fifo_size) {
2807 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_FIFOEN |
2808 ATMEL_US_RXFCLR | ATMEL_US_TXFLCLR);
2809 atmel_uart_writel(port, ATMEL_US_FMR,
2810 atmel_port->cache.fmr);
2811 atmel_uart_writel(port, ATMEL_US_FIER,
2812 atmel_port->cache.fimr);
2813 }
2814 atmel_start_rx(port);
2815 }
2816
2817 spin_lock_irqsave(&atmel_port->lock_suspended, flags);
2818 if (atmel_port->pending) {
2819 atmel_handle_receive(port, atmel_port->pending);
2820 atmel_handle_status(port, atmel_port->pending,
2821 atmel_port->pending_status);
2822 atmel_handle_transmit(port, atmel_port->pending);
2823 atmel_port->pending = 0;
2824 }
2825 atmel_port->suspended = false;
2826 spin_unlock_irqrestore(&atmel_port->lock_suspended, flags);
2827
2828 uart_resume_port(&atmel_uart, port);
2829 device_set_wakeup_enable(dev, atmel_port->may_wakeup);
2830
2831 return 0;
2832 }
2833
atmel_serial_probe_fifos(struct atmel_uart_port * atmel_port,struct platform_device * pdev)2834 static void atmel_serial_probe_fifos(struct atmel_uart_port *atmel_port,
2835 struct platform_device *pdev)
2836 {
2837 atmel_port->fifo_size = 0;
2838 atmel_port->rts_low = 0;
2839 atmel_port->rts_high = 0;
2840
2841 if (of_property_read_u32(pdev->dev.of_node,
2842 "atmel,fifo-size",
2843 &atmel_port->fifo_size))
2844 return;
2845
2846 if (!atmel_port->fifo_size)
2847 return;
2848
2849 if (atmel_port->fifo_size < ATMEL_MIN_FIFO_SIZE) {
2850 atmel_port->fifo_size = 0;
2851 dev_err(&pdev->dev, "Invalid FIFO size\n");
2852 return;
2853 }
2854
2855 /*
2856 * 0 <= rts_low <= rts_high <= fifo_size
2857 * Once their CTS line asserted by the remote peer, some x86 UARTs tend
2858 * to flush their internal TX FIFO, commonly up to 16 data, before
2859 * actually stopping to send new data. So we try to set the RTS High
2860 * Threshold to a reasonably high value respecting this 16 data
2861 * empirical rule when possible.
2862 */
2863 atmel_port->rts_high = max_t(int, atmel_port->fifo_size >> 1,
2864 atmel_port->fifo_size - ATMEL_RTS_HIGH_OFFSET);
2865 atmel_port->rts_low = max_t(int, atmel_port->fifo_size >> 2,
2866 atmel_port->fifo_size - ATMEL_RTS_LOW_OFFSET);
2867
2868 dev_info(&pdev->dev, "Using FIFO (%u data)\n",
2869 atmel_port->fifo_size);
2870 dev_dbg(&pdev->dev, "RTS High Threshold : %2u data\n",
2871 atmel_port->rts_high);
2872 dev_dbg(&pdev->dev, "RTS Low Threshold : %2u data\n",
2873 atmel_port->rts_low);
2874 }
2875
atmel_serial_probe(struct platform_device * pdev)2876 static int atmel_serial_probe(struct platform_device *pdev)
2877 {
2878 struct atmel_uart_port *atmel_port;
2879 struct device_node *np = pdev->dev.parent->of_node;
2880 void *data;
2881 int ret;
2882 bool rs485_enabled;
2883
2884 BUILD_BUG_ON(ATMEL_SERIAL_RINGSIZE & (ATMEL_SERIAL_RINGSIZE - 1));
2885
2886 /*
2887 * In device tree there is no node with "atmel,at91rm9200-usart-serial"
2888 * as compatible string. This driver is probed by at91-usart mfd driver
2889 * which is just a wrapper over the atmel_serial driver and
2890 * spi-at91-usart driver. All attributes needed by this driver are
2891 * found in of_node of parent.
2892 */
2893 pdev->dev.of_node = np;
2894
2895 ret = of_alias_get_id(np, "serial");
2896 if (ret < 0)
2897 /* port id not found in platform data nor device-tree aliases:
2898 * auto-enumerate it */
2899 ret = find_first_zero_bit(atmel_ports_in_use, ATMEL_MAX_UART);
2900
2901 if (ret >= ATMEL_MAX_UART) {
2902 ret = -ENODEV;
2903 goto err;
2904 }
2905
2906 if (test_and_set_bit(ret, atmel_ports_in_use)) {
2907 /* port already in use */
2908 ret = -EBUSY;
2909 goto err;
2910 }
2911
2912 atmel_port = &atmel_ports[ret];
2913 atmel_port->backup_imr = 0;
2914 atmel_port->uart.line = ret;
2915 atmel_port->uart.has_sysrq = IS_ENABLED(CONFIG_SERIAL_ATMEL_CONSOLE);
2916 atmel_serial_probe_fifos(atmel_port, pdev);
2917
2918 atomic_set(&atmel_port->tasklet_shutdown, 0);
2919 spin_lock_init(&atmel_port->lock_suspended);
2920
2921 atmel_port->clk = devm_clk_get(&pdev->dev, "usart");
2922 if (IS_ERR(atmel_port->clk)) {
2923 ret = PTR_ERR(atmel_port->clk);
2924 goto err;
2925 }
2926 ret = clk_prepare_enable(atmel_port->clk);
2927 if (ret)
2928 goto err;
2929
2930 atmel_port->gclk = devm_clk_get_optional(&pdev->dev, "gclk");
2931 if (IS_ERR(atmel_port->gclk)) {
2932 ret = PTR_ERR(atmel_port->gclk);
2933 goto err_clk_disable_unprepare;
2934 }
2935
2936 ret = atmel_init_port(atmel_port, pdev);
2937 if (ret)
2938 goto err_clk_disable_unprepare;
2939
2940 atmel_port->gpios = mctrl_gpio_init(&atmel_port->uart, 0);
2941 if (IS_ERR(atmel_port->gpios)) {
2942 ret = PTR_ERR(atmel_port->gpios);
2943 goto err_clk_disable_unprepare;
2944 }
2945
2946 if (!atmel_use_pdc_rx(&atmel_port->uart)) {
2947 ret = -ENOMEM;
2948 data = kmalloc_array(ATMEL_SERIAL_RINGSIZE,
2949 sizeof(struct atmel_uart_char),
2950 GFP_KERNEL);
2951 if (!data)
2952 goto err_clk_disable_unprepare;
2953 atmel_port->rx_ring.buf = data;
2954 }
2955
2956 rs485_enabled = atmel_port->uart.rs485.flags & SER_RS485_ENABLED;
2957
2958 ret = uart_add_one_port(&atmel_uart, &atmel_port->uart);
2959 if (ret)
2960 goto err_add_port;
2961
2962 device_init_wakeup(&pdev->dev, 1);
2963 platform_set_drvdata(pdev, atmel_port);
2964
2965 if (rs485_enabled) {
2966 atmel_uart_writel(&atmel_port->uart, ATMEL_US_MR,
2967 ATMEL_US_USMODE_NORMAL);
2968 atmel_uart_writel(&atmel_port->uart, ATMEL_US_CR,
2969 ATMEL_US_RTSEN);
2970 }
2971
2972 /*
2973 * Get port name of usart or uart
2974 */
2975 atmel_get_ip_name(&atmel_port->uart);
2976
2977 /*
2978 * The peripheral clock can now safely be disabled till the port
2979 * is used
2980 */
2981 clk_disable_unprepare(atmel_port->clk);
2982
2983 return 0;
2984
2985 err_add_port:
2986 kfree(atmel_port->rx_ring.buf);
2987 atmel_port->rx_ring.buf = NULL;
2988 err_clk_disable_unprepare:
2989 clk_disable_unprepare(atmel_port->clk);
2990 clear_bit(atmel_port->uart.line, atmel_ports_in_use);
2991 err:
2992 return ret;
2993 }
2994
2995 /*
2996 * Even if the driver is not modular, it makes sense to be able to
2997 * unbind a device: there can be many bound devices, and there are
2998 * situations where dynamic binding and unbinding can be useful.
2999 *
3000 * For example, a connected device can require a specific firmware update
3001 * protocol that needs bitbanging on IO lines, but use the regular serial
3002 * port in the normal case.
3003 */
atmel_serial_remove(struct platform_device * pdev)3004 static int atmel_serial_remove(struct platform_device *pdev)
3005 {
3006 struct uart_port *port = platform_get_drvdata(pdev);
3007 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
3008
3009 tasklet_kill(&atmel_port->tasklet_rx);
3010 tasklet_kill(&atmel_port->tasklet_tx);
3011
3012 device_init_wakeup(&pdev->dev, 0);
3013
3014 uart_remove_one_port(&atmel_uart, port);
3015
3016 kfree(atmel_port->rx_ring.buf);
3017
3018 /* "port" is allocated statically, so we shouldn't free it */
3019
3020 clear_bit(port->line, atmel_ports_in_use);
3021
3022 pdev->dev.of_node = NULL;
3023
3024 return 0;
3025 }
3026
3027 static SIMPLE_DEV_PM_OPS(atmel_serial_pm_ops, atmel_serial_suspend,
3028 atmel_serial_resume);
3029
3030 static struct platform_driver atmel_serial_driver = {
3031 .probe = atmel_serial_probe,
3032 .remove = atmel_serial_remove,
3033 .driver = {
3034 .name = "atmel_usart_serial",
3035 .of_match_table = of_match_ptr(atmel_serial_dt_ids),
3036 .pm = pm_ptr(&atmel_serial_pm_ops),
3037 },
3038 };
3039
atmel_serial_init(void)3040 static int __init atmel_serial_init(void)
3041 {
3042 int ret;
3043
3044 ret = uart_register_driver(&atmel_uart);
3045 if (ret)
3046 return ret;
3047
3048 ret = platform_driver_register(&atmel_serial_driver);
3049 if (ret)
3050 uart_unregister_driver(&atmel_uart);
3051
3052 return ret;
3053 }
3054 device_initcall(atmel_serial_init);
3055
