1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *	Support for the asynchronous serial interface (DUART) included
4  *	in the BCM1250 and derived System-On-a-Chip (SOC) devices.
5  *
6  *	Copyright (c) 2007  Maciej W. Rozycki
7  *
8  *	Derived from drivers/char/sb1250_duart.c for which the following
9  *	copyright applies:
10  *
11  *	Copyright (c) 2000, 2001, 2002, 2003, 2004  Broadcom Corporation
12  *
13  *	References:
14  *
15  *	"BCM1250/BCM1125/BCM1125H User Manual", Broadcom Corporation
16  */
17 
18 #include <linux/compiler.h>
19 #include <linux/console.h>
20 #include <linux/delay.h>
21 #include <linux/errno.h>
22 #include <linux/init.h>
23 #include <linux/interrupt.h>
24 #include <linux/ioport.h>
25 #include <linux/kernel.h>
26 #include <linux/module.h>
27 #include <linux/major.h>
28 #include <linux/serial.h>
29 #include <linux/serial_core.h>
30 #include <linux/spinlock.h>
31 #include <linux/sysrq.h>
32 #include <linux/tty.h>
33 #include <linux/tty_flip.h>
34 #include <linux/types.h>
35 
36 #include <linux/refcount.h>
37 #include <linux/io.h>
38 
39 #include <asm/sibyte/sb1250.h>
40 #include <asm/sibyte/sb1250_uart.h>
41 #include <asm/sibyte/swarm.h>
42 
43 
44 #if defined(CONFIG_SIBYTE_BCM1x80)
45 #include <asm/sibyte/bcm1480_regs.h>
46 #include <asm/sibyte/bcm1480_int.h>
47 
48 #define SBD_CHANREGS(line)	A_BCM1480_DUART_CHANREG((line), 0)
49 #define SBD_CTRLREGS(line)	A_BCM1480_DUART_CTRLREG((line), 0)
50 #define SBD_INT(line)		(K_BCM1480_INT_UART_0 + (line))
51 
52 #define DUART_CHANREG_SPACING	BCM1480_DUART_CHANREG_SPACING
53 
54 #define R_DUART_IMRREG(line)	R_BCM1480_DUART_IMRREG(line)
55 #define R_DUART_INCHREG(line)	R_BCM1480_DUART_INCHREG(line)
56 #define R_DUART_ISRREG(line)	R_BCM1480_DUART_ISRREG(line)
57 
58 #elif defined(CONFIG_SIBYTE_SB1250) || defined(CONFIG_SIBYTE_BCM112X)
59 #include <asm/sibyte/sb1250_regs.h>
60 #include <asm/sibyte/sb1250_int.h>
61 
62 #define SBD_CHANREGS(line)	A_DUART_CHANREG((line), 0)
63 #define SBD_CTRLREGS(line)	A_DUART_CTRLREG(0)
64 #define SBD_INT(line)		(K_INT_UART_0 + (line))
65 
66 #else
67 #error invalid SB1250 UART configuration
68 
69 #endif
70 
71 
72 MODULE_AUTHOR("Maciej W. Rozycki <macro@linux-mips.org>");
73 MODULE_DESCRIPTION("BCM1xxx on-chip DUART serial driver");
74 MODULE_LICENSE("GPL");
75 
76 
77 #define DUART_MAX_CHIP 2
78 #define DUART_MAX_SIDE 2
79 
80 /*
81  * Per-port state.
82  */
83 struct sbd_port {
84 	struct sbd_duart	*duart;
85 	struct uart_port	port;
86 	unsigned char __iomem	*memctrl;
87 	int			tx_stopped;
88 	int			initialised;
89 };
90 
91 /*
92  * Per-DUART state for the shared register space.
93  */
94 struct sbd_duart {
95 	struct sbd_port		sport[2];
96 	unsigned long		mapctrl;
97 	refcount_t		map_guard;
98 };
99 
100 #define to_sport(uport) container_of(uport, struct sbd_port, port)
101 
102 static struct sbd_duart sbd_duarts[DUART_MAX_CHIP];
103 
104 
105 /*
106  * Reading and writing SB1250 DUART registers.
107  *
108  * There are three register spaces: two per-channel ones and
109  * a shared one.  We have to define accessors appropriately.
110  * All registers are 64-bit and all but the Baud Rate Clock
111  * registers only define 8 least significant bits.  There is
112  * also a workaround to take into account.  Raw accessors use
113  * the full register width, but cooked ones truncate it
114  * intentionally so that the rest of the driver does not care.
115  */
116 static u64 __read_sbdchn(struct sbd_port *sport, int reg)
117 {
118 	void __iomem *csr = sport->port.membase + reg;
119 
120 	return __raw_readq(csr);
121 }
122 
123 static u64 __read_sbdshr(struct sbd_port *sport, int reg)
124 {
125 	void __iomem *csr = sport->memctrl + reg;
126 
127 	return __raw_readq(csr);
128 }
129 
130 static void __write_sbdchn(struct sbd_port *sport, int reg, u64 value)
131 {
132 	void __iomem *csr = sport->port.membase + reg;
133 
134 	__raw_writeq(value, csr);
135 }
136 
137 static void __write_sbdshr(struct sbd_port *sport, int reg, u64 value)
138 {
139 	void __iomem *csr = sport->memctrl + reg;
140 
141 	__raw_writeq(value, csr);
142 }
143 
144 /*
145  * In bug 1956, we get glitches that can mess up uart registers.  This
146  * "read-mode-reg after any register access" is an accepted workaround.
147  */
148 static void __war_sbd1956(struct sbd_port *sport)
149 {
150 	__read_sbdchn(sport, R_DUART_MODE_REG_1);
151 	__read_sbdchn(sport, R_DUART_MODE_REG_2);
152 }
153 
154 static unsigned char read_sbdchn(struct sbd_port *sport, int reg)
155 {
156 	unsigned char retval;
157 
158 	retval = __read_sbdchn(sport, reg);
159 	if (IS_ENABLED(CONFIG_SB1_PASS_2_WORKAROUNDS))
160 		__war_sbd1956(sport);
161 	return retval;
162 }
163 
164 static unsigned char read_sbdshr(struct sbd_port *sport, int reg)
165 {
166 	unsigned char retval;
167 
168 	retval = __read_sbdshr(sport, reg);
169 	if (IS_ENABLED(CONFIG_SB1_PASS_2_WORKAROUNDS))
170 		__war_sbd1956(sport);
171 	return retval;
172 }
173 
174 static void write_sbdchn(struct sbd_port *sport, int reg, unsigned int value)
175 {
176 	__write_sbdchn(sport, reg, value);
177 	if (IS_ENABLED(CONFIG_SB1_PASS_2_WORKAROUNDS))
178 		__war_sbd1956(sport);
179 }
180 
181 static void write_sbdshr(struct sbd_port *sport, int reg, unsigned int value)
182 {
183 	__write_sbdshr(sport, reg, value);
184 	if (IS_ENABLED(CONFIG_SB1_PASS_2_WORKAROUNDS))
185 		__war_sbd1956(sport);
186 }
187 
188 
189 static int sbd_receive_ready(struct sbd_port *sport)
190 {
191 	return read_sbdchn(sport, R_DUART_STATUS) & M_DUART_RX_RDY;
192 }
193 
194 static int sbd_receive_drain(struct sbd_port *sport)
195 {
196 	int loops = 10000;
197 
198 	while (sbd_receive_ready(sport) && --loops)
199 		read_sbdchn(sport, R_DUART_RX_HOLD);
200 	return loops;
201 }
202 
203 static int __maybe_unused sbd_transmit_ready(struct sbd_port *sport)
204 {
205 	return read_sbdchn(sport, R_DUART_STATUS) & M_DUART_TX_RDY;
206 }
207 
208 static int __maybe_unused sbd_transmit_drain(struct sbd_port *sport)
209 {
210 	int loops = 10000;
211 
212 	while (!sbd_transmit_ready(sport) && --loops)
213 		udelay(2);
214 	return loops;
215 }
216 
217 static int sbd_transmit_empty(struct sbd_port *sport)
218 {
219 	return read_sbdchn(sport, R_DUART_STATUS) & M_DUART_TX_EMT;
220 }
221 
222 static int sbd_line_drain(struct sbd_port *sport)
223 {
224 	int loops = 10000;
225 
226 	while (!sbd_transmit_empty(sport) && --loops)
227 		udelay(2);
228 	return loops;
229 }
230 
231 
232 static unsigned int sbd_tx_empty(struct uart_port *uport)
233 {
234 	struct sbd_port *sport = to_sport(uport);
235 
236 	return sbd_transmit_empty(sport) ? TIOCSER_TEMT : 0;
237 }
238 
239 static unsigned int sbd_get_mctrl(struct uart_port *uport)
240 {
241 	struct sbd_port *sport = to_sport(uport);
242 	unsigned int mctrl, status;
243 
244 	status = read_sbdshr(sport, R_DUART_IN_PORT);
245 	status >>= (uport->line) % 2;
246 	mctrl = (!(status & M_DUART_IN_PIN0_VAL) ? TIOCM_CTS : 0) |
247 		(!(status & M_DUART_IN_PIN4_VAL) ? TIOCM_CAR : 0) |
248 		(!(status & M_DUART_RIN0_PIN) ? TIOCM_RNG : 0) |
249 		(!(status & M_DUART_IN_PIN2_VAL) ? TIOCM_DSR : 0);
250 	return mctrl;
251 }
252 
253 static void sbd_set_mctrl(struct uart_port *uport, unsigned int mctrl)
254 {
255 	struct sbd_port *sport = to_sport(uport);
256 	unsigned int clr = 0, set = 0, mode2;
257 
258 	if (mctrl & TIOCM_DTR)
259 		set |= M_DUART_SET_OPR2;
260 	else
261 		clr |= M_DUART_CLR_OPR2;
262 	if (mctrl & TIOCM_RTS)
263 		set |= M_DUART_SET_OPR0;
264 	else
265 		clr |= M_DUART_CLR_OPR0;
266 	clr <<= (uport->line) % 2;
267 	set <<= (uport->line) % 2;
268 
269 	mode2 = read_sbdchn(sport, R_DUART_MODE_REG_2);
270 	mode2 &= ~M_DUART_CHAN_MODE;
271 	if (mctrl & TIOCM_LOOP)
272 		mode2 |= V_DUART_CHAN_MODE_LCL_LOOP;
273 	else
274 		mode2 |= V_DUART_CHAN_MODE_NORMAL;
275 
276 	write_sbdshr(sport, R_DUART_CLEAR_OPR, clr);
277 	write_sbdshr(sport, R_DUART_SET_OPR, set);
278 	write_sbdchn(sport, R_DUART_MODE_REG_2, mode2);
279 }
280 
281 static void sbd_stop_tx(struct uart_port *uport)
282 {
283 	struct sbd_port *sport = to_sport(uport);
284 
285 	write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_DIS);
286 	sport->tx_stopped = 1;
287 };
288 
289 static void sbd_start_tx(struct uart_port *uport)
290 {
291 	struct sbd_port *sport = to_sport(uport);
292 	unsigned int mask;
293 
294 	/* Enable tx interrupts.  */
295 	mask = read_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2));
296 	mask |= M_DUART_IMR_TX;
297 	write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2), mask);
298 
299 	/* Go!, go!, go!...  */
300 	write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_EN);
301 	sport->tx_stopped = 0;
302 };
303 
304 static void sbd_stop_rx(struct uart_port *uport)
305 {
306 	struct sbd_port *sport = to_sport(uport);
307 
308 	write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2), 0);
309 };
310 
311 static void sbd_enable_ms(struct uart_port *uport)
312 {
313 	struct sbd_port *sport = to_sport(uport);
314 
315 	write_sbdchn(sport, R_DUART_AUXCTL_X,
316 		     M_DUART_CIN_CHNG_ENA | M_DUART_CTS_CHNG_ENA);
317 }
318 
319 static void sbd_break_ctl(struct uart_port *uport, int break_state)
320 {
321 	struct sbd_port *sport = to_sport(uport);
322 
323 	if (break_state == -1)
324 		write_sbdchn(sport, R_DUART_CMD, V_DUART_MISC_CMD_START_BREAK);
325 	else
326 		write_sbdchn(sport, R_DUART_CMD, V_DUART_MISC_CMD_STOP_BREAK);
327 }
328 
329 
330 static void sbd_receive_chars(struct sbd_port *sport)
331 {
332 	struct uart_port *uport = &sport->port;
333 	struct uart_icount *icount;
334 	unsigned int status;
335 	int count;
336 	u8 ch, flag;
337 
338 	for (count = 16; count; count--) {
339 		status = read_sbdchn(sport, R_DUART_STATUS);
340 		if (!(status & M_DUART_RX_RDY))
341 			break;
342 
343 		ch = read_sbdchn(sport, R_DUART_RX_HOLD);
344 
345 		flag = TTY_NORMAL;
346 
347 		icount = &uport->icount;
348 		icount->rx++;
349 
350 		if (unlikely(status &
351 			     (M_DUART_RCVD_BRK | M_DUART_FRM_ERR |
352 			      M_DUART_PARITY_ERR | M_DUART_OVRUN_ERR))) {
353 			if (status & M_DUART_RCVD_BRK) {
354 				icount->brk++;
355 				if (uart_handle_break(uport))
356 					continue;
357 			} else if (status & M_DUART_FRM_ERR)
358 				icount->frame++;
359 			else if (status & M_DUART_PARITY_ERR)
360 				icount->parity++;
361 			if (status & M_DUART_OVRUN_ERR)
362 				icount->overrun++;
363 
364 			status &= uport->read_status_mask;
365 			if (status & M_DUART_RCVD_BRK)
366 				flag = TTY_BREAK;
367 			else if (status & M_DUART_FRM_ERR)
368 				flag = TTY_FRAME;
369 			else if (status & M_DUART_PARITY_ERR)
370 				flag = TTY_PARITY;
371 		}
372 
373 		if (uart_handle_sysrq_char(uport, ch))
374 			continue;
375 
376 		uart_insert_char(uport, status, M_DUART_OVRUN_ERR, ch, flag);
377 	}
378 
379 	tty_flip_buffer_push(&uport->state->port);
380 }
381 
382 static void sbd_transmit_chars(struct sbd_port *sport)
383 {
384 	struct uart_port *uport = &sport->port;
385 	struct circ_buf *xmit = &sport->port.state->xmit;
386 	unsigned int mask;
387 	int stop_tx;
388 
389 	/* XON/XOFF chars.  */
390 	if (sport->port.x_char) {
391 		write_sbdchn(sport, R_DUART_TX_HOLD, sport->port.x_char);
392 		sport->port.icount.tx++;
393 		sport->port.x_char = 0;
394 		return;
395 	}
396 
397 	/* If nothing to do or stopped or hardware stopped.  */
398 	stop_tx = (uart_circ_empty(xmit) || uart_tx_stopped(&sport->port));
399 
400 	/* Send char.  */
401 	if (!stop_tx) {
402 		write_sbdchn(sport, R_DUART_TX_HOLD, xmit->buf[xmit->tail]);
403 		uart_xmit_advance(&sport->port, 1);
404 
405 		if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
406 			uart_write_wakeup(&sport->port);
407 	}
408 
409 	/* Are we are done?  */
410 	if (stop_tx || uart_circ_empty(xmit)) {
411 		/* Disable tx interrupts.  */
412 		mask = read_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2));
413 		mask &= ~M_DUART_IMR_TX;
414 		write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2), mask);
415 	}
416 }
417 
418 static void sbd_status_handle(struct sbd_port *sport)
419 {
420 	struct uart_port *uport = &sport->port;
421 	unsigned int delta;
422 
423 	delta = read_sbdshr(sport, R_DUART_INCHREG((uport->line) % 2));
424 	delta >>= (uport->line) % 2;
425 
426 	if (delta & (M_DUART_IN_PIN0_VAL << S_DUART_IN_PIN_CHNG))
427 		uart_handle_cts_change(uport, !(delta & M_DUART_IN_PIN0_VAL));
428 
429 	if (delta & (M_DUART_IN_PIN2_VAL << S_DUART_IN_PIN_CHNG))
430 		uport->icount.dsr++;
431 
432 	if (delta & ((M_DUART_IN_PIN2_VAL | M_DUART_IN_PIN0_VAL) <<
433 		     S_DUART_IN_PIN_CHNG))
434 		wake_up_interruptible(&uport->state->port.delta_msr_wait);
435 }
436 
437 static irqreturn_t sbd_interrupt(int irq, void *dev_id)
438 {
439 	struct sbd_port *sport = dev_id;
440 	struct uart_port *uport = &sport->port;
441 	irqreturn_t status = IRQ_NONE;
442 	unsigned int intstat;
443 	int count;
444 
445 	for (count = 16; count; count--) {
446 		intstat = read_sbdshr(sport,
447 				      R_DUART_ISRREG((uport->line) % 2));
448 		intstat &= read_sbdshr(sport,
449 				       R_DUART_IMRREG((uport->line) % 2));
450 		intstat &= M_DUART_ISR_ALL;
451 		if (!intstat)
452 			break;
453 
454 		if (intstat & M_DUART_ISR_RX)
455 			sbd_receive_chars(sport);
456 		if (intstat & M_DUART_ISR_IN)
457 			sbd_status_handle(sport);
458 		if (intstat & M_DUART_ISR_TX)
459 			sbd_transmit_chars(sport);
460 
461 		status = IRQ_HANDLED;
462 	}
463 
464 	return status;
465 }
466 
467 
468 static int sbd_startup(struct uart_port *uport)
469 {
470 	struct sbd_port *sport = to_sport(uport);
471 	unsigned int mode1;
472 	int ret;
473 
474 	ret = request_irq(sport->port.irq, sbd_interrupt,
475 			  IRQF_SHARED, "sb1250-duart", sport);
476 	if (ret)
477 		return ret;
478 
479 	/* Clear the receive FIFO.  */
480 	sbd_receive_drain(sport);
481 
482 	/* Clear the interrupt registers.  */
483 	write_sbdchn(sport, R_DUART_CMD, V_DUART_MISC_CMD_RESET_BREAK_INT);
484 	read_sbdshr(sport, R_DUART_INCHREG((uport->line) % 2));
485 
486 	/* Set rx/tx interrupt to FIFO available.  */
487 	mode1 = read_sbdchn(sport, R_DUART_MODE_REG_1);
488 	mode1 &= ~(M_DUART_RX_IRQ_SEL_RXFULL | M_DUART_TX_IRQ_SEL_TXEMPT);
489 	write_sbdchn(sport, R_DUART_MODE_REG_1, mode1);
490 
491 	/* Disable tx, enable rx.  */
492 	write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_DIS | M_DUART_RX_EN);
493 	sport->tx_stopped = 1;
494 
495 	/* Enable interrupts.  */
496 	write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2),
497 		     M_DUART_IMR_IN | M_DUART_IMR_RX);
498 
499 	return 0;
500 }
501 
502 static void sbd_shutdown(struct uart_port *uport)
503 {
504 	struct sbd_port *sport = to_sport(uport);
505 
506 	write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_DIS | M_DUART_RX_DIS);
507 	sport->tx_stopped = 1;
508 	free_irq(sport->port.irq, sport);
509 }
510 
511 
512 static void sbd_init_port(struct sbd_port *sport)
513 {
514 	struct uart_port *uport = &sport->port;
515 
516 	if (sport->initialised)
517 		return;
518 
519 	/* There is no DUART reset feature, so just set some sane defaults.  */
520 	write_sbdchn(sport, R_DUART_CMD, V_DUART_MISC_CMD_RESET_TX);
521 	write_sbdchn(sport, R_DUART_CMD, V_DUART_MISC_CMD_RESET_RX);
522 	write_sbdchn(sport, R_DUART_MODE_REG_1, V_DUART_BITS_PER_CHAR_8);
523 	write_sbdchn(sport, R_DUART_MODE_REG_2, 0);
524 	write_sbdchn(sport, R_DUART_FULL_CTL,
525 		     V_DUART_INT_TIME(0) | V_DUART_SIG_FULL(15));
526 	write_sbdchn(sport, R_DUART_OPCR_X, 0);
527 	write_sbdchn(sport, R_DUART_AUXCTL_X, 0);
528 	write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2), 0);
529 
530 	sport->initialised = 1;
531 }
532 
533 static void sbd_set_termios(struct uart_port *uport, struct ktermios *termios,
534 			    const struct ktermios *old_termios)
535 {
536 	struct sbd_port *sport = to_sport(uport);
537 	unsigned int mode1 = 0, mode2 = 0, aux = 0;
538 	unsigned int mode1mask = 0, mode2mask = 0, auxmask = 0;
539 	unsigned int oldmode1, oldmode2, oldaux;
540 	unsigned int baud, brg;
541 	unsigned int command;
542 
543 	mode1mask |= ~(M_DUART_PARITY_MODE | M_DUART_PARITY_TYPE_ODD |
544 		       M_DUART_BITS_PER_CHAR);
545 	mode2mask |= ~M_DUART_STOP_BIT_LEN_2;
546 	auxmask |= ~M_DUART_CTS_CHNG_ENA;
547 
548 	/* Byte size.  */
549 	switch (termios->c_cflag & CSIZE) {
550 	case CS5:
551 	case CS6:
552 		/* Unsupported, leave unchanged.  */
553 		mode1mask |= M_DUART_PARITY_MODE;
554 		break;
555 	case CS7:
556 		mode1 |= V_DUART_BITS_PER_CHAR_7;
557 		break;
558 	case CS8:
559 	default:
560 		mode1 |= V_DUART_BITS_PER_CHAR_8;
561 		break;
562 	}
563 
564 	/* Parity and stop bits.  */
565 	if (termios->c_cflag & CSTOPB)
566 		mode2 |= M_DUART_STOP_BIT_LEN_2;
567 	else
568 		mode2 |= M_DUART_STOP_BIT_LEN_1;
569 	if (termios->c_cflag & PARENB)
570 		mode1 |= V_DUART_PARITY_MODE_ADD;
571 	else
572 		mode1 |= V_DUART_PARITY_MODE_NONE;
573 	if (termios->c_cflag & PARODD)
574 		mode1 |= M_DUART_PARITY_TYPE_ODD;
575 	else
576 		mode1 |= M_DUART_PARITY_TYPE_EVEN;
577 
578 	baud = uart_get_baud_rate(uport, termios, old_termios, 1200, 5000000);
579 	brg = V_DUART_BAUD_RATE(baud);
580 	/* The actual lower bound is 1221bps, so compensate.  */
581 	if (brg > M_DUART_CLK_COUNTER)
582 		brg = M_DUART_CLK_COUNTER;
583 
584 	uart_update_timeout(uport, termios->c_cflag, baud);
585 
586 	uport->read_status_mask = M_DUART_OVRUN_ERR;
587 	if (termios->c_iflag & INPCK)
588 		uport->read_status_mask |= M_DUART_FRM_ERR |
589 					   M_DUART_PARITY_ERR;
590 	if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
591 		uport->read_status_mask |= M_DUART_RCVD_BRK;
592 
593 	uport->ignore_status_mask = 0;
594 	if (termios->c_iflag & IGNPAR)
595 		uport->ignore_status_mask |= M_DUART_FRM_ERR |
596 					     M_DUART_PARITY_ERR;
597 	if (termios->c_iflag & IGNBRK) {
598 		uport->ignore_status_mask |= M_DUART_RCVD_BRK;
599 		if (termios->c_iflag & IGNPAR)
600 			uport->ignore_status_mask |= M_DUART_OVRUN_ERR;
601 	}
602 
603 	if (termios->c_cflag & CREAD)
604 		command = M_DUART_RX_EN;
605 	else
606 		command = M_DUART_RX_DIS;
607 
608 	if (termios->c_cflag & CRTSCTS)
609 		aux |= M_DUART_CTS_CHNG_ENA;
610 	else
611 		aux &= ~M_DUART_CTS_CHNG_ENA;
612 
613 	spin_lock(&uport->lock);
614 
615 	if (sport->tx_stopped)
616 		command |= M_DUART_TX_DIS;
617 	else
618 		command |= M_DUART_TX_EN;
619 
620 	oldmode1 = read_sbdchn(sport, R_DUART_MODE_REG_1) & mode1mask;
621 	oldmode2 = read_sbdchn(sport, R_DUART_MODE_REG_2) & mode2mask;
622 	oldaux = read_sbdchn(sport, R_DUART_AUXCTL_X) & auxmask;
623 
624 	if (!sport->tx_stopped)
625 		sbd_line_drain(sport);
626 	write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_DIS | M_DUART_RX_DIS);
627 
628 	write_sbdchn(sport, R_DUART_MODE_REG_1, mode1 | oldmode1);
629 	write_sbdchn(sport, R_DUART_MODE_REG_2, mode2 | oldmode2);
630 	write_sbdchn(sport, R_DUART_CLK_SEL, brg);
631 	write_sbdchn(sport, R_DUART_AUXCTL_X, aux | oldaux);
632 
633 	write_sbdchn(sport, R_DUART_CMD, command);
634 
635 	spin_unlock(&uport->lock);
636 }
637 
638 
639 static const char *sbd_type(struct uart_port *uport)
640 {
641 	return "SB1250 DUART";
642 }
643 
644 static void sbd_release_port(struct uart_port *uport)
645 {
646 	struct sbd_port *sport = to_sport(uport);
647 	struct sbd_duart *duart = sport->duart;
648 
649 	iounmap(sport->memctrl);
650 	sport->memctrl = NULL;
651 	iounmap(uport->membase);
652 	uport->membase = NULL;
653 
654 	if(refcount_dec_and_test(&duart->map_guard))
655 		release_mem_region(duart->mapctrl, DUART_CHANREG_SPACING);
656 	release_mem_region(uport->mapbase, DUART_CHANREG_SPACING);
657 }
658 
659 static int sbd_map_port(struct uart_port *uport)
660 {
661 	const char *err = KERN_ERR "sbd: Cannot map MMIO\n";
662 	struct sbd_port *sport = to_sport(uport);
663 	struct sbd_duart *duart = sport->duart;
664 
665 	if (!uport->membase)
666 		uport->membase = ioremap(uport->mapbase,
667 						 DUART_CHANREG_SPACING);
668 	if (!uport->membase) {
669 		printk(err);
670 		return -ENOMEM;
671 	}
672 
673 	if (!sport->memctrl)
674 		sport->memctrl = ioremap(duart->mapctrl,
675 						 DUART_CHANREG_SPACING);
676 	if (!sport->memctrl) {
677 		printk(err);
678 		iounmap(uport->membase);
679 		uport->membase = NULL;
680 		return -ENOMEM;
681 	}
682 
683 	return 0;
684 }
685 
686 static int sbd_request_port(struct uart_port *uport)
687 {
688 	const char *err = KERN_ERR "sbd: Unable to reserve MMIO resource\n";
689 	struct sbd_duart *duart = to_sport(uport)->duart;
690 	int ret = 0;
691 
692 	if (!request_mem_region(uport->mapbase, DUART_CHANREG_SPACING,
693 				"sb1250-duart")) {
694 		printk(err);
695 		return -EBUSY;
696 	}
697 	refcount_inc(&duart->map_guard);
698 	if (refcount_read(&duart->map_guard) == 1) {
699 		if (!request_mem_region(duart->mapctrl, DUART_CHANREG_SPACING,
700 					"sb1250-duart")) {
701 			refcount_dec(&duart->map_guard);
702 			printk(err);
703 			ret = -EBUSY;
704 		}
705 	}
706 	if (!ret) {
707 		ret = sbd_map_port(uport);
708 		if (ret) {
709 			if (refcount_dec_and_test(&duart->map_guard))
710 				release_mem_region(duart->mapctrl,
711 						   DUART_CHANREG_SPACING);
712 		}
713 	}
714 	if (ret) {
715 		release_mem_region(uport->mapbase, DUART_CHANREG_SPACING);
716 		return ret;
717 	}
718 	return 0;
719 }
720 
721 static void sbd_config_port(struct uart_port *uport, int flags)
722 {
723 	struct sbd_port *sport = to_sport(uport);
724 
725 	if (flags & UART_CONFIG_TYPE) {
726 		if (sbd_request_port(uport))
727 			return;
728 
729 		uport->type = PORT_SB1250_DUART;
730 
731 		sbd_init_port(sport);
732 	}
733 }
734 
735 static int sbd_verify_port(struct uart_port *uport, struct serial_struct *ser)
736 {
737 	int ret = 0;
738 
739 	if (ser->type != PORT_UNKNOWN && ser->type != PORT_SB1250_DUART)
740 		ret = -EINVAL;
741 	if (ser->irq != uport->irq)
742 		ret = -EINVAL;
743 	if (ser->baud_base != uport->uartclk / 16)
744 		ret = -EINVAL;
745 	return ret;
746 }
747 
748 
749 static const struct uart_ops sbd_ops = {
750 	.tx_empty	= sbd_tx_empty,
751 	.set_mctrl	= sbd_set_mctrl,
752 	.get_mctrl	= sbd_get_mctrl,
753 	.stop_tx	= sbd_stop_tx,
754 	.start_tx	= sbd_start_tx,
755 	.stop_rx	= sbd_stop_rx,
756 	.enable_ms	= sbd_enable_ms,
757 	.break_ctl	= sbd_break_ctl,
758 	.startup	= sbd_startup,
759 	.shutdown	= sbd_shutdown,
760 	.set_termios	= sbd_set_termios,
761 	.type		= sbd_type,
762 	.release_port	= sbd_release_port,
763 	.request_port	= sbd_request_port,
764 	.config_port	= sbd_config_port,
765 	.verify_port	= sbd_verify_port,
766 };
767 
768 /* Initialize SB1250 DUART port structures.  */
769 static void __init sbd_probe_duarts(void)
770 {
771 	static int probed;
772 	int chip, side;
773 	int max_lines, line;
774 
775 	if (probed)
776 		return;
777 
778 	/* Set the number of available units based on the SOC type.  */
779 	switch (soc_type) {
780 	case K_SYS_SOC_TYPE_BCM1x55:
781 	case K_SYS_SOC_TYPE_BCM1x80:
782 		max_lines = 4;
783 		break;
784 	default:
785 		/* Assume at least two serial ports at the normal address.  */
786 		max_lines = 2;
787 		break;
788 	}
789 
790 	probed = 1;
791 
792 	for (chip = 0, line = 0; chip < DUART_MAX_CHIP && line < max_lines;
793 	     chip++) {
794 		sbd_duarts[chip].mapctrl = SBD_CTRLREGS(line);
795 
796 		for (side = 0; side < DUART_MAX_SIDE && line < max_lines;
797 		     side++, line++) {
798 			struct sbd_port *sport = &sbd_duarts[chip].sport[side];
799 			struct uart_port *uport = &sport->port;
800 
801 			sport->duart	= &sbd_duarts[chip];
802 
803 			uport->irq	= SBD_INT(line);
804 			uport->uartclk	= 100000000 / 20 * 16;
805 			uport->fifosize	= 16;
806 			uport->iotype	= UPIO_MEM;
807 			uport->flags	= UPF_BOOT_AUTOCONF;
808 			uport->ops	= &sbd_ops;
809 			uport->line	= line;
810 			uport->mapbase	= SBD_CHANREGS(line);
811 			uport->has_sysrq = IS_ENABLED(CONFIG_SERIAL_SB1250_DUART_CONSOLE);
812 		}
813 	}
814 }
815 
816 
817 #ifdef CONFIG_SERIAL_SB1250_DUART_CONSOLE
818 /*
819  * Serial console stuff.  Very basic, polling driver for doing serial
820  * console output.  The console_lock is held by the caller, so we
821  * shouldn't be interrupted for more console activity.
822  */
823 static void sbd_console_putchar(struct uart_port *uport, unsigned char ch)
824 {
825 	struct sbd_port *sport = to_sport(uport);
826 
827 	sbd_transmit_drain(sport);
828 	write_sbdchn(sport, R_DUART_TX_HOLD, ch);
829 }
830 
831 static void sbd_console_write(struct console *co, const char *s,
832 			      unsigned int count)
833 {
834 	int chip = co->index / DUART_MAX_SIDE;
835 	int side = co->index % DUART_MAX_SIDE;
836 	struct sbd_port *sport = &sbd_duarts[chip].sport[side];
837 	struct uart_port *uport = &sport->port;
838 	unsigned long flags;
839 	unsigned int mask;
840 
841 	/* Disable transmit interrupts and enable the transmitter. */
842 	spin_lock_irqsave(&uport->lock, flags);
843 	mask = read_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2));
844 	write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2),
845 		     mask & ~M_DUART_IMR_TX);
846 	write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_EN);
847 	spin_unlock_irqrestore(&uport->lock, flags);
848 
849 	uart_console_write(&sport->port, s, count, sbd_console_putchar);
850 
851 	/* Restore transmit interrupts and the transmitter enable. */
852 	spin_lock_irqsave(&uport->lock, flags);
853 	sbd_line_drain(sport);
854 	if (sport->tx_stopped)
855 		write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_DIS);
856 	write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2), mask);
857 	spin_unlock_irqrestore(&uport->lock, flags);
858 }
859 
860 static int __init sbd_console_setup(struct console *co, char *options)
861 {
862 	int chip = co->index / DUART_MAX_SIDE;
863 	int side = co->index % DUART_MAX_SIDE;
864 	struct sbd_port *sport = &sbd_duarts[chip].sport[side];
865 	struct uart_port *uport = &sport->port;
866 	int baud = 115200;
867 	int bits = 8;
868 	int parity = 'n';
869 	int flow = 'n';
870 	int ret;
871 
872 	if (!sport->duart)
873 		return -ENXIO;
874 
875 	ret = sbd_map_port(uport);
876 	if (ret)
877 		return ret;
878 
879 	sbd_init_port(sport);
880 
881 	if (options)
882 		uart_parse_options(options, &baud, &parity, &bits, &flow);
883 	return uart_set_options(uport, co, baud, parity, bits, flow);
884 }
885 
886 static struct uart_driver sbd_reg;
887 static struct console sbd_console = {
888 	.name	= "duart",
889 	.write	= sbd_console_write,
890 	.device	= uart_console_device,
891 	.setup	= sbd_console_setup,
892 	.flags	= CON_PRINTBUFFER,
893 	.index	= -1,
894 	.data	= &sbd_reg
895 };
896 
897 static int __init sbd_serial_console_init(void)
898 {
899 	sbd_probe_duarts();
900 	register_console(&sbd_console);
901 
902 	return 0;
903 }
904 
905 console_initcall(sbd_serial_console_init);
906 
907 #define SERIAL_SB1250_DUART_CONSOLE	&sbd_console
908 #else
909 #define SERIAL_SB1250_DUART_CONSOLE	NULL
910 #endif /* CONFIG_SERIAL_SB1250_DUART_CONSOLE */
911 
912 
913 static struct uart_driver sbd_reg = {
914 	.owner		= THIS_MODULE,
915 	.driver_name	= "sb1250_duart",
916 	.dev_name	= "duart",
917 	.major		= TTY_MAJOR,
918 	.minor		= SB1250_DUART_MINOR_BASE,
919 	.nr		= DUART_MAX_CHIP * DUART_MAX_SIDE,
920 	.cons		= SERIAL_SB1250_DUART_CONSOLE,
921 };
922 
923 /* Set up the driver and register it.  */
924 static int __init sbd_init(void)
925 {
926 	int i, ret;
927 
928 	sbd_probe_duarts();
929 
930 	ret = uart_register_driver(&sbd_reg);
931 	if (ret)
932 		return ret;
933 
934 	for (i = 0; i < DUART_MAX_CHIP * DUART_MAX_SIDE; i++) {
935 		struct sbd_duart *duart = &sbd_duarts[i / DUART_MAX_SIDE];
936 		struct sbd_port *sport = &duart->sport[i % DUART_MAX_SIDE];
937 		struct uart_port *uport = &sport->port;
938 
939 		if (sport->duart)
940 			uart_add_one_port(&sbd_reg, uport);
941 	}
942 
943 	return 0;
944 }
945 
946 /* Unload the driver.  Unregister stuff, get ready to go away.  */
947 static void __exit sbd_exit(void)
948 {
949 	int i;
950 
951 	for (i = DUART_MAX_CHIP * DUART_MAX_SIDE - 1; i >= 0; i--) {
952 		struct sbd_duart *duart = &sbd_duarts[i / DUART_MAX_SIDE];
953 		struct sbd_port *sport = &duart->sport[i % DUART_MAX_SIDE];
954 		struct uart_port *uport = &sport->port;
955 
956 		if (sport->duart)
957 			uart_remove_one_port(&sbd_reg, uport);
958 	}
959 
960 	uart_unregister_driver(&sbd_reg);
961 }
962 
963 module_init(sbd_init);
964 module_exit(sbd_exit);
965