xref: /openbmc/linux/drivers/tty/serial/sunsab.c (revision 3c6a73cc)
1 /* sunsab.c: ASYNC Driver for the SIEMENS SAB82532 DUSCC.
2  *
3  * Copyright (C) 1997  Eddie C. Dost  (ecd@skynet.be)
4  * Copyright (C) 2002, 2006  David S. Miller (davem@davemloft.net)
5  *
6  * Rewrote buffer handling to use CIRC(Circular Buffer) macros.
7  *   Maxim Krasnyanskiy <maxk@qualcomm.com>
8  *
9  * Fixed to use tty_get_baud_rate, and to allow for arbitrary baud
10  * rates to be programmed into the UART.  Also eliminated a lot of
11  * duplicated code in the console setup.
12  *   Theodore Ts'o <tytso@mit.edu>, 2001-Oct-12
13  *
14  * Ported to new 2.5.x UART layer.
15  *   David S. Miller <davem@davemloft.net>
16  */
17 
18 #include <linux/module.h>
19 #include <linux/kernel.h>
20 #include <linux/errno.h>
21 #include <linux/tty.h>
22 #include <linux/tty_flip.h>
23 #include <linux/major.h>
24 #include <linux/string.h>
25 #include <linux/ptrace.h>
26 #include <linux/ioport.h>
27 #include <linux/circ_buf.h>
28 #include <linux/serial.h>
29 #include <linux/sysrq.h>
30 #include <linux/console.h>
31 #include <linux/spinlock.h>
32 #include <linux/slab.h>
33 #include <linux/delay.h>
34 #include <linux/init.h>
35 #include <linux/of_device.h>
36 
37 #include <asm/io.h>
38 #include <asm/irq.h>
39 #include <asm/prom.h>
40 #include <asm/setup.h>
41 
42 #if defined(CONFIG_SERIAL_SUNSAB_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
43 #define SUPPORT_SYSRQ
44 #endif
45 
46 #include <linux/serial_core.h>
47 #include <linux/sunserialcore.h>
48 
49 #include "sunsab.h"
50 
51 struct uart_sunsab_port {
52 	struct uart_port		port;		/* Generic UART port	*/
53 	union sab82532_async_regs	__iomem *regs;	/* Chip registers	*/
54 	unsigned long			irqflags;	/* IRQ state flags	*/
55 	int				dsr;		/* Current DSR state	*/
56 	unsigned int			cec_timeout;	/* Chip poll timeout... */
57 	unsigned int			tec_timeout;	/* likewise		*/
58 	unsigned char			interrupt_mask0;/* ISR0 masking		*/
59 	unsigned char			interrupt_mask1;/* ISR1 masking		*/
60 	unsigned char			pvr_dtr_bit;	/* Which PVR bit is DTR */
61 	unsigned char			pvr_dsr_bit;	/* Which PVR bit is DSR */
62 	unsigned int			gis_shift;
63 	int				type;		/* SAB82532 version	*/
64 
65 	/* Setting configuration bits while the transmitter is active
66 	 * can cause garbage characters to get emitted by the chip.
67 	 * Therefore, we cache such writes here and do the real register
68 	 * write the next time the transmitter becomes idle.
69 	 */
70 	unsigned int			cached_ebrg;
71 	unsigned char			cached_mode;
72 	unsigned char			cached_pvr;
73 	unsigned char			cached_dafo;
74 };
75 
76 /*
77  * This assumes you have a 29.4912 MHz clock for your UART.
78  */
79 #define SAB_BASE_BAUD ( 29491200 / 16 )
80 
81 static char *sab82532_version[16] = {
82 	"V1.0", "V2.0", "V3.2", "V(0x03)",
83 	"V(0x04)", "V(0x05)", "V(0x06)", "V(0x07)",
84 	"V(0x08)", "V(0x09)", "V(0x0a)", "V(0x0b)",
85 	"V(0x0c)", "V(0x0d)", "V(0x0e)", "V(0x0f)"
86 };
87 
88 #define SAB82532_MAX_TEC_TIMEOUT 200000	/* 1 character time (at 50 baud) */
89 #define SAB82532_MAX_CEC_TIMEOUT  50000	/* 2.5 TX CLKs (at 50 baud) */
90 
91 #define SAB82532_RECV_FIFO_SIZE	32      /* Standard async fifo sizes */
92 #define SAB82532_XMIT_FIFO_SIZE	32
93 
94 static __inline__ void sunsab_tec_wait(struct uart_sunsab_port *up)
95 {
96 	int timeout = up->tec_timeout;
97 
98 	while ((readb(&up->regs->r.star) & SAB82532_STAR_TEC) && --timeout)
99 		udelay(1);
100 }
101 
102 static __inline__ void sunsab_cec_wait(struct uart_sunsab_port *up)
103 {
104 	int timeout = up->cec_timeout;
105 
106 	while ((readb(&up->regs->r.star) & SAB82532_STAR_CEC) && --timeout)
107 		udelay(1);
108 }
109 
110 static struct tty_port *
111 receive_chars(struct uart_sunsab_port *up,
112 	      union sab82532_irq_status *stat)
113 {
114 	struct tty_port *port = NULL;
115 	unsigned char buf[32];
116 	int saw_console_brk = 0;
117 	int free_fifo = 0;
118 	int count = 0;
119 	int i;
120 
121 	if (up->port.state != NULL)		/* Unopened serial console */
122 		port = &up->port.state->port;
123 
124 	/* Read number of BYTES (Character + Status) available. */
125 	if (stat->sreg.isr0 & SAB82532_ISR0_RPF) {
126 		count = SAB82532_RECV_FIFO_SIZE;
127 		free_fifo++;
128 	}
129 
130 	if (stat->sreg.isr0 & SAB82532_ISR0_TCD) {
131 		count = readb(&up->regs->r.rbcl) & (SAB82532_RECV_FIFO_SIZE - 1);
132 		free_fifo++;
133 	}
134 
135 	/* Issue a FIFO read command in case we where idle. */
136 	if (stat->sreg.isr0 & SAB82532_ISR0_TIME) {
137 		sunsab_cec_wait(up);
138 		writeb(SAB82532_CMDR_RFRD, &up->regs->w.cmdr);
139 		return port;
140 	}
141 
142 	if (stat->sreg.isr0 & SAB82532_ISR0_RFO)
143 		free_fifo++;
144 
145 	/* Read the FIFO. */
146 	for (i = 0; i < count; i++)
147 		buf[i] = readb(&up->regs->r.rfifo[i]);
148 
149 	/* Issue Receive Message Complete command. */
150 	if (free_fifo) {
151 		sunsab_cec_wait(up);
152 		writeb(SAB82532_CMDR_RMC, &up->regs->w.cmdr);
153 	}
154 
155 	/* Count may be zero for BRK, so we check for it here */
156 	if ((stat->sreg.isr1 & SAB82532_ISR1_BRK) &&
157 	    (up->port.line == up->port.cons->index))
158 		saw_console_brk = 1;
159 
160 	if (count == 0) {
161 		if (unlikely(stat->sreg.isr1 & SAB82532_ISR1_BRK)) {
162 			stat->sreg.isr0 &= ~(SAB82532_ISR0_PERR |
163 					     SAB82532_ISR0_FERR);
164 			up->port.icount.brk++;
165 			uart_handle_break(&up->port);
166 		}
167 	}
168 
169 	for (i = 0; i < count; i++) {
170 		unsigned char ch = buf[i], flag;
171 
172 		flag = TTY_NORMAL;
173 		up->port.icount.rx++;
174 
175 		if (unlikely(stat->sreg.isr0 & (SAB82532_ISR0_PERR |
176 						SAB82532_ISR0_FERR |
177 						SAB82532_ISR0_RFO)) ||
178 		    unlikely(stat->sreg.isr1 & SAB82532_ISR1_BRK)) {
179 			/*
180 			 * For statistics only
181 			 */
182 			if (stat->sreg.isr1 & SAB82532_ISR1_BRK) {
183 				stat->sreg.isr0 &= ~(SAB82532_ISR0_PERR |
184 						     SAB82532_ISR0_FERR);
185 				up->port.icount.brk++;
186 				/*
187 				 * We do the SysRQ and SAK checking
188 				 * here because otherwise the break
189 				 * may get masked by ignore_status_mask
190 				 * or read_status_mask.
191 				 */
192 				if (uart_handle_break(&up->port))
193 					continue;
194 			} else if (stat->sreg.isr0 & SAB82532_ISR0_PERR)
195 				up->port.icount.parity++;
196 			else if (stat->sreg.isr0 & SAB82532_ISR0_FERR)
197 				up->port.icount.frame++;
198 			if (stat->sreg.isr0 & SAB82532_ISR0_RFO)
199 				up->port.icount.overrun++;
200 
201 			/*
202 			 * Mask off conditions which should be ingored.
203 			 */
204 			stat->sreg.isr0 &= (up->port.read_status_mask & 0xff);
205 			stat->sreg.isr1 &= ((up->port.read_status_mask >> 8) & 0xff);
206 
207 			if (stat->sreg.isr1 & SAB82532_ISR1_BRK) {
208 				flag = TTY_BREAK;
209 			} else if (stat->sreg.isr0 & SAB82532_ISR0_PERR)
210 				flag = TTY_PARITY;
211 			else if (stat->sreg.isr0 & SAB82532_ISR0_FERR)
212 				flag = TTY_FRAME;
213 		}
214 
215 		if (uart_handle_sysrq_char(&up->port, ch) || !port)
216 			continue;
217 
218 		if ((stat->sreg.isr0 & (up->port.ignore_status_mask & 0xff)) == 0 &&
219 		    (stat->sreg.isr1 & ((up->port.ignore_status_mask >> 8) & 0xff)) == 0)
220 			tty_insert_flip_char(port, ch, flag);
221 		if (stat->sreg.isr0 & SAB82532_ISR0_RFO)
222 			tty_insert_flip_char(port, 0, TTY_OVERRUN);
223 	}
224 
225 	if (saw_console_brk)
226 		sun_do_break();
227 
228 	return port;
229 }
230 
231 static void sunsab_stop_tx(struct uart_port *);
232 static void sunsab_tx_idle(struct uart_sunsab_port *);
233 
234 static void transmit_chars(struct uart_sunsab_port *up,
235 			   union sab82532_irq_status *stat)
236 {
237 	struct circ_buf *xmit = &up->port.state->xmit;
238 	int i;
239 
240 	if (stat->sreg.isr1 & SAB82532_ISR1_ALLS) {
241 		up->interrupt_mask1 |= SAB82532_IMR1_ALLS;
242 		writeb(up->interrupt_mask1, &up->regs->w.imr1);
243 		set_bit(SAB82532_ALLS, &up->irqflags);
244 	}
245 
246 #if 0 /* bde@nwlink.com says this check causes problems */
247 	if (!(stat->sreg.isr1 & SAB82532_ISR1_XPR))
248 		return;
249 #endif
250 
251 	if (!(readb(&up->regs->r.star) & SAB82532_STAR_XFW))
252 		return;
253 
254 	set_bit(SAB82532_XPR, &up->irqflags);
255 	sunsab_tx_idle(up);
256 
257 	if (uart_circ_empty(xmit) || uart_tx_stopped(&up->port)) {
258 		up->interrupt_mask1 |= SAB82532_IMR1_XPR;
259 		writeb(up->interrupt_mask1, &up->regs->w.imr1);
260 		return;
261 	}
262 
263 	up->interrupt_mask1 &= ~(SAB82532_IMR1_ALLS|SAB82532_IMR1_XPR);
264 	writeb(up->interrupt_mask1, &up->regs->w.imr1);
265 	clear_bit(SAB82532_ALLS, &up->irqflags);
266 
267 	/* Stuff 32 bytes into Transmit FIFO. */
268 	clear_bit(SAB82532_XPR, &up->irqflags);
269 	for (i = 0; i < up->port.fifosize; i++) {
270 		writeb(xmit->buf[xmit->tail],
271 		       &up->regs->w.xfifo[i]);
272 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
273 		up->port.icount.tx++;
274 		if (uart_circ_empty(xmit))
275 			break;
276 	}
277 
278 	/* Issue a Transmit Frame command. */
279 	sunsab_cec_wait(up);
280 	writeb(SAB82532_CMDR_XF, &up->regs->w.cmdr);
281 
282 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
283 		uart_write_wakeup(&up->port);
284 
285 	if (uart_circ_empty(xmit))
286 		sunsab_stop_tx(&up->port);
287 }
288 
289 static void check_status(struct uart_sunsab_port *up,
290 			 union sab82532_irq_status *stat)
291 {
292 	if (stat->sreg.isr0 & SAB82532_ISR0_CDSC)
293 		uart_handle_dcd_change(&up->port,
294 				       !(readb(&up->regs->r.vstr) & SAB82532_VSTR_CD));
295 
296 	if (stat->sreg.isr1 & SAB82532_ISR1_CSC)
297 		uart_handle_cts_change(&up->port,
298 				       (readb(&up->regs->r.star) & SAB82532_STAR_CTS));
299 
300 	if ((readb(&up->regs->r.pvr) & up->pvr_dsr_bit) ^ up->dsr) {
301 		up->dsr = (readb(&up->regs->r.pvr) & up->pvr_dsr_bit) ? 0 : 1;
302 		up->port.icount.dsr++;
303 	}
304 
305 	wake_up_interruptible(&up->port.state->port.delta_msr_wait);
306 }
307 
308 static irqreturn_t sunsab_interrupt(int irq, void *dev_id)
309 {
310 	struct uart_sunsab_port *up = dev_id;
311 	struct tty_port *port = NULL;
312 	union sab82532_irq_status status;
313 	unsigned long flags;
314 	unsigned char gis;
315 
316 	spin_lock_irqsave(&up->port.lock, flags);
317 
318 	status.stat = 0;
319 	gis = readb(&up->regs->r.gis) >> up->gis_shift;
320 	if (gis & 1)
321 		status.sreg.isr0 = readb(&up->regs->r.isr0);
322 	if (gis & 2)
323 		status.sreg.isr1 = readb(&up->regs->r.isr1);
324 
325 	if (status.stat) {
326 		if ((status.sreg.isr0 & (SAB82532_ISR0_TCD | SAB82532_ISR0_TIME |
327 					 SAB82532_ISR0_RFO | SAB82532_ISR0_RPF)) ||
328 		    (status.sreg.isr1 & SAB82532_ISR1_BRK))
329 			port = receive_chars(up, &status);
330 		if ((status.sreg.isr0 & SAB82532_ISR0_CDSC) ||
331 		    (status.sreg.isr1 & SAB82532_ISR1_CSC))
332 			check_status(up, &status);
333 		if (status.sreg.isr1 & (SAB82532_ISR1_ALLS | SAB82532_ISR1_XPR))
334 			transmit_chars(up, &status);
335 	}
336 
337 	spin_unlock_irqrestore(&up->port.lock, flags);
338 
339 	if (port)
340 		tty_flip_buffer_push(port);
341 
342 	return IRQ_HANDLED;
343 }
344 
345 /* port->lock is not held.  */
346 static unsigned int sunsab_tx_empty(struct uart_port *port)
347 {
348 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
349 	int ret;
350 
351 	/* Do not need a lock for a state test like this.  */
352 	if (test_bit(SAB82532_ALLS, &up->irqflags))
353 		ret = TIOCSER_TEMT;
354 	else
355 		ret = 0;
356 
357 	return ret;
358 }
359 
360 /* port->lock held by caller.  */
361 static void sunsab_set_mctrl(struct uart_port *port, unsigned int mctrl)
362 {
363 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
364 
365 	if (mctrl & TIOCM_RTS) {
366 		up->cached_mode &= ~SAB82532_MODE_FRTS;
367 		up->cached_mode |= SAB82532_MODE_RTS;
368 	} else {
369 		up->cached_mode |= (SAB82532_MODE_FRTS |
370 				    SAB82532_MODE_RTS);
371 	}
372 	if (mctrl & TIOCM_DTR) {
373 		up->cached_pvr &= ~(up->pvr_dtr_bit);
374 	} else {
375 		up->cached_pvr |= up->pvr_dtr_bit;
376 	}
377 
378 	set_bit(SAB82532_REGS_PENDING, &up->irqflags);
379 	if (test_bit(SAB82532_XPR, &up->irqflags))
380 		sunsab_tx_idle(up);
381 }
382 
383 /* port->lock is held by caller and interrupts are disabled.  */
384 static unsigned int sunsab_get_mctrl(struct uart_port *port)
385 {
386 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
387 	unsigned char val;
388 	unsigned int result;
389 
390 	result = 0;
391 
392 	val = readb(&up->regs->r.pvr);
393 	result |= (val & up->pvr_dsr_bit) ? 0 : TIOCM_DSR;
394 
395 	val = readb(&up->regs->r.vstr);
396 	result |= (val & SAB82532_VSTR_CD) ? 0 : TIOCM_CAR;
397 
398 	val = readb(&up->regs->r.star);
399 	result |= (val & SAB82532_STAR_CTS) ? TIOCM_CTS : 0;
400 
401 	return result;
402 }
403 
404 /* port->lock held by caller.  */
405 static void sunsab_stop_tx(struct uart_port *port)
406 {
407 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
408 
409 	up->interrupt_mask1 |= SAB82532_IMR1_XPR;
410 	writeb(up->interrupt_mask1, &up->regs->w.imr1);
411 }
412 
413 /* port->lock held by caller.  */
414 static void sunsab_tx_idle(struct uart_sunsab_port *up)
415 {
416 	if (test_bit(SAB82532_REGS_PENDING, &up->irqflags)) {
417 		u8 tmp;
418 
419 		clear_bit(SAB82532_REGS_PENDING, &up->irqflags);
420 		writeb(up->cached_mode, &up->regs->rw.mode);
421 		writeb(up->cached_pvr, &up->regs->rw.pvr);
422 		writeb(up->cached_dafo, &up->regs->w.dafo);
423 
424 		writeb(up->cached_ebrg & 0xff, &up->regs->w.bgr);
425 		tmp = readb(&up->regs->rw.ccr2);
426 		tmp &= ~0xc0;
427 		tmp |= (up->cached_ebrg >> 2) & 0xc0;
428 		writeb(tmp, &up->regs->rw.ccr2);
429 	}
430 }
431 
432 /* port->lock held by caller.  */
433 static void sunsab_start_tx(struct uart_port *port)
434 {
435 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
436 	struct circ_buf *xmit = &up->port.state->xmit;
437 	int i;
438 
439 	if (uart_circ_empty(xmit) || uart_tx_stopped(port))
440 		return;
441 
442 	up->interrupt_mask1 &= ~(SAB82532_IMR1_ALLS|SAB82532_IMR1_XPR);
443 	writeb(up->interrupt_mask1, &up->regs->w.imr1);
444 
445 	if (!test_bit(SAB82532_XPR, &up->irqflags))
446 		return;
447 
448 	clear_bit(SAB82532_ALLS, &up->irqflags);
449 	clear_bit(SAB82532_XPR, &up->irqflags);
450 
451 	for (i = 0; i < up->port.fifosize; i++) {
452 		writeb(xmit->buf[xmit->tail],
453 		       &up->regs->w.xfifo[i]);
454 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
455 		up->port.icount.tx++;
456 		if (uart_circ_empty(xmit))
457 			break;
458 	}
459 
460 	/* Issue a Transmit Frame command.  */
461 	sunsab_cec_wait(up);
462 	writeb(SAB82532_CMDR_XF, &up->regs->w.cmdr);
463 }
464 
465 /* port->lock is not held.  */
466 static void sunsab_send_xchar(struct uart_port *port, char ch)
467 {
468 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
469 	unsigned long flags;
470 
471 	if (ch == __DISABLED_CHAR)
472 		return;
473 
474 	spin_lock_irqsave(&up->port.lock, flags);
475 
476 	sunsab_tec_wait(up);
477 	writeb(ch, &up->regs->w.tic);
478 
479 	spin_unlock_irqrestore(&up->port.lock, flags);
480 }
481 
482 /* port->lock held by caller.  */
483 static void sunsab_stop_rx(struct uart_port *port)
484 {
485 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
486 
487 	up->interrupt_mask0 |= SAB82532_IMR0_TCD;
488 	writeb(up->interrupt_mask1, &up->regs->w.imr0);
489 }
490 
491 /* port->lock is not held.  */
492 static void sunsab_break_ctl(struct uart_port *port, int break_state)
493 {
494 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
495 	unsigned long flags;
496 	unsigned char val;
497 
498 	spin_lock_irqsave(&up->port.lock, flags);
499 
500 	val = up->cached_dafo;
501 	if (break_state)
502 		val |= SAB82532_DAFO_XBRK;
503 	else
504 		val &= ~SAB82532_DAFO_XBRK;
505 	up->cached_dafo = val;
506 
507 	set_bit(SAB82532_REGS_PENDING, &up->irqflags);
508 	if (test_bit(SAB82532_XPR, &up->irqflags))
509 		sunsab_tx_idle(up);
510 
511 	spin_unlock_irqrestore(&up->port.lock, flags);
512 }
513 
514 /* port->lock is not held.  */
515 static int sunsab_startup(struct uart_port *port)
516 {
517 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
518 	unsigned long flags;
519 	unsigned char tmp;
520 	int err = request_irq(up->port.irq, sunsab_interrupt,
521 			      IRQF_SHARED, "sab", up);
522 	if (err)
523 		return err;
524 
525 	spin_lock_irqsave(&up->port.lock, flags);
526 
527 	/*
528 	 * Wait for any commands or immediate characters
529 	 */
530 	sunsab_cec_wait(up);
531 	sunsab_tec_wait(up);
532 
533 	/*
534 	 * Clear the FIFO buffers.
535 	 */
536 	writeb(SAB82532_CMDR_RRES, &up->regs->w.cmdr);
537 	sunsab_cec_wait(up);
538 	writeb(SAB82532_CMDR_XRES, &up->regs->w.cmdr);
539 
540 	/*
541 	 * Clear the interrupt registers.
542 	 */
543 	(void) readb(&up->regs->r.isr0);
544 	(void) readb(&up->regs->r.isr1);
545 
546 	/*
547 	 * Now, initialize the UART
548 	 */
549 	writeb(0, &up->regs->w.ccr0);				/* power-down */
550 	writeb(SAB82532_CCR0_MCE | SAB82532_CCR0_SC_NRZ |
551 	       SAB82532_CCR0_SM_ASYNC, &up->regs->w.ccr0);
552 	writeb(SAB82532_CCR1_ODS | SAB82532_CCR1_BCR | 7, &up->regs->w.ccr1);
553 	writeb(SAB82532_CCR2_BDF | SAB82532_CCR2_SSEL |
554 	       SAB82532_CCR2_TOE, &up->regs->w.ccr2);
555 	writeb(0, &up->regs->w.ccr3);
556 	writeb(SAB82532_CCR4_MCK4 | SAB82532_CCR4_EBRG, &up->regs->w.ccr4);
557 	up->cached_mode = (SAB82532_MODE_RTS | SAB82532_MODE_FCTS |
558 			   SAB82532_MODE_RAC);
559 	writeb(up->cached_mode, &up->regs->w.mode);
560 	writeb(SAB82532_RFC_DPS|SAB82532_RFC_RFTH_32, &up->regs->w.rfc);
561 
562 	tmp = readb(&up->regs->rw.ccr0);
563 	tmp |= SAB82532_CCR0_PU;	/* power-up */
564 	writeb(tmp, &up->regs->rw.ccr0);
565 
566 	/*
567 	 * Finally, enable interrupts
568 	 */
569 	up->interrupt_mask0 = (SAB82532_IMR0_PERR | SAB82532_IMR0_FERR |
570 			       SAB82532_IMR0_PLLA);
571 	writeb(up->interrupt_mask0, &up->regs->w.imr0);
572 	up->interrupt_mask1 = (SAB82532_IMR1_BRKT | SAB82532_IMR1_ALLS |
573 			       SAB82532_IMR1_XOFF | SAB82532_IMR1_TIN |
574 			       SAB82532_IMR1_CSC | SAB82532_IMR1_XON |
575 			       SAB82532_IMR1_XPR);
576 	writeb(up->interrupt_mask1, &up->regs->w.imr1);
577 	set_bit(SAB82532_ALLS, &up->irqflags);
578 	set_bit(SAB82532_XPR, &up->irqflags);
579 
580 	spin_unlock_irqrestore(&up->port.lock, flags);
581 
582 	return 0;
583 }
584 
585 /* port->lock is not held.  */
586 static void sunsab_shutdown(struct uart_port *port)
587 {
588 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
589 	unsigned long flags;
590 
591 	spin_lock_irqsave(&up->port.lock, flags);
592 
593 	/* Disable Interrupts */
594 	up->interrupt_mask0 = 0xff;
595 	writeb(up->interrupt_mask0, &up->regs->w.imr0);
596 	up->interrupt_mask1 = 0xff;
597 	writeb(up->interrupt_mask1, &up->regs->w.imr1);
598 
599 	/* Disable break condition */
600 	up->cached_dafo = readb(&up->regs->rw.dafo);
601 	up->cached_dafo &= ~SAB82532_DAFO_XBRK;
602 	writeb(up->cached_dafo, &up->regs->rw.dafo);
603 
604 	/* Disable Receiver */
605 	up->cached_mode &= ~SAB82532_MODE_RAC;
606 	writeb(up->cached_mode, &up->regs->rw.mode);
607 
608 	/*
609 	 * XXX FIXME
610 	 *
611 	 * If the chip is powered down here the system hangs/crashes during
612 	 * reboot or shutdown.  This needs to be investigated further,
613 	 * similar behaviour occurs in 2.4 when the driver is configured
614 	 * as a module only.  One hint may be that data is sometimes
615 	 * transmitted at 9600 baud during shutdown (regardless of the
616 	 * speed the chip was configured for when the port was open).
617 	 */
618 #if 0
619 	/* Power Down */
620 	tmp = readb(&up->regs->rw.ccr0);
621 	tmp &= ~SAB82532_CCR0_PU;
622 	writeb(tmp, &up->regs->rw.ccr0);
623 #endif
624 
625 	spin_unlock_irqrestore(&up->port.lock, flags);
626 	free_irq(up->port.irq, up);
627 }
628 
629 /*
630  * This is used to figure out the divisor speeds.
631  *
632  * The formula is:    Baud = SAB_BASE_BAUD / ((N + 1) * (1 << M)),
633  *
634  * with               0 <= N < 64 and 0 <= M < 16
635  */
636 
637 static void calc_ebrg(int baud, int *n_ret, int *m_ret)
638 {
639 	int	n, m;
640 
641 	if (baud == 0) {
642 		*n_ret = 0;
643 		*m_ret = 0;
644 		return;
645 	}
646 
647 	/*
648 	 * We scale numbers by 10 so that we get better accuracy
649 	 * without having to use floating point.  Here we increment m
650 	 * until n is within the valid range.
651 	 */
652 	n = (SAB_BASE_BAUD * 10) / baud;
653 	m = 0;
654 	while (n >= 640) {
655 		n = n / 2;
656 		m++;
657 	}
658 	n = (n+5) / 10;
659 	/*
660 	 * We try very hard to avoid speeds with M == 0 since they may
661 	 * not work correctly for XTAL frequences above 10 MHz.
662 	 */
663 	if ((m == 0) && ((n & 1) == 0)) {
664 		n = n / 2;
665 		m++;
666 	}
667 	*n_ret = n - 1;
668 	*m_ret = m;
669 }
670 
671 /* Internal routine, port->lock is held and local interrupts are disabled.  */
672 static void sunsab_convert_to_sab(struct uart_sunsab_port *up, unsigned int cflag,
673 				  unsigned int iflag, unsigned int baud,
674 				  unsigned int quot)
675 {
676 	unsigned char dafo;
677 	int bits, n, m;
678 
679 	/* Byte size and parity */
680 	switch (cflag & CSIZE) {
681 	      case CS5: dafo = SAB82532_DAFO_CHL5; bits = 7; break;
682 	      case CS6: dafo = SAB82532_DAFO_CHL6; bits = 8; break;
683 	      case CS7: dafo = SAB82532_DAFO_CHL7; bits = 9; break;
684 	      case CS8: dafo = SAB82532_DAFO_CHL8; bits = 10; break;
685 	      /* Never happens, but GCC is too dumb to figure it out */
686 	      default:  dafo = SAB82532_DAFO_CHL5; bits = 7; break;
687 	}
688 
689 	if (cflag & CSTOPB) {
690 		dafo |= SAB82532_DAFO_STOP;
691 		bits++;
692 	}
693 
694 	if (cflag & PARENB) {
695 		dafo |= SAB82532_DAFO_PARE;
696 		bits++;
697 	}
698 
699 	if (cflag & PARODD) {
700 		dafo |= SAB82532_DAFO_PAR_ODD;
701 	} else {
702 		dafo |= SAB82532_DAFO_PAR_EVEN;
703 	}
704 	up->cached_dafo = dafo;
705 
706 	calc_ebrg(baud, &n, &m);
707 
708 	up->cached_ebrg = n | (m << 6);
709 
710 	up->tec_timeout = (10 * 1000000) / baud;
711 	up->cec_timeout = up->tec_timeout >> 2;
712 
713 	/* CTS flow control flags */
714 	/* We encode read_status_mask and ignore_status_mask like so:
715 	 *
716 	 * ---------------------
717 	 * | ... | ISR1 | ISR0 |
718 	 * ---------------------
719 	 *  ..    15   8 7    0
720 	 */
721 
722 	up->port.read_status_mask = (SAB82532_ISR0_TCD | SAB82532_ISR0_TIME |
723 				     SAB82532_ISR0_RFO | SAB82532_ISR0_RPF |
724 				     SAB82532_ISR0_CDSC);
725 	up->port.read_status_mask |= (SAB82532_ISR1_CSC |
726 				      SAB82532_ISR1_ALLS |
727 				      SAB82532_ISR1_XPR) << 8;
728 	if (iflag & INPCK)
729 		up->port.read_status_mask |= (SAB82532_ISR0_PERR |
730 					      SAB82532_ISR0_FERR);
731 	if (iflag & (IGNBRK | BRKINT | PARMRK))
732 		up->port.read_status_mask |= (SAB82532_ISR1_BRK << 8);
733 
734 	/*
735 	 * Characteres to ignore
736 	 */
737 	up->port.ignore_status_mask = 0;
738 	if (iflag & IGNPAR)
739 		up->port.ignore_status_mask |= (SAB82532_ISR0_PERR |
740 						SAB82532_ISR0_FERR);
741 	if (iflag & IGNBRK) {
742 		up->port.ignore_status_mask |= (SAB82532_ISR1_BRK << 8);
743 		/*
744 		 * If we're ignoring parity and break indicators,
745 		 * ignore overruns too (for real raw support).
746 		 */
747 		if (iflag & IGNPAR)
748 			up->port.ignore_status_mask |= SAB82532_ISR0_RFO;
749 	}
750 
751 	/*
752 	 * ignore all characters if CREAD is not set
753 	 */
754 	if ((cflag & CREAD) == 0)
755 		up->port.ignore_status_mask |= (SAB82532_ISR0_RPF |
756 						SAB82532_ISR0_TCD);
757 
758 	uart_update_timeout(&up->port, cflag,
759 			    (up->port.uartclk / (16 * quot)));
760 
761 	/* Now schedule a register update when the chip's
762 	 * transmitter is idle.
763 	 */
764 	up->cached_mode |= SAB82532_MODE_RAC;
765 	set_bit(SAB82532_REGS_PENDING, &up->irqflags);
766 	if (test_bit(SAB82532_XPR, &up->irqflags))
767 		sunsab_tx_idle(up);
768 }
769 
770 /* port->lock is not held.  */
771 static void sunsab_set_termios(struct uart_port *port, struct ktermios *termios,
772 			       struct ktermios *old)
773 {
774 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
775 	unsigned long flags;
776 	unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
777 	unsigned int quot = uart_get_divisor(port, baud);
778 
779 	spin_lock_irqsave(&up->port.lock, flags);
780 	sunsab_convert_to_sab(up, termios->c_cflag, termios->c_iflag, baud, quot);
781 	spin_unlock_irqrestore(&up->port.lock, flags);
782 }
783 
784 static const char *sunsab_type(struct uart_port *port)
785 {
786 	struct uart_sunsab_port *up = (void *)port;
787 	static char buf[36];
788 
789 	sprintf(buf, "SAB82532 %s", sab82532_version[up->type]);
790 	return buf;
791 }
792 
793 static void sunsab_release_port(struct uart_port *port)
794 {
795 }
796 
797 static int sunsab_request_port(struct uart_port *port)
798 {
799 	return 0;
800 }
801 
802 static void sunsab_config_port(struct uart_port *port, int flags)
803 {
804 }
805 
806 static int sunsab_verify_port(struct uart_port *port, struct serial_struct *ser)
807 {
808 	return -EINVAL;
809 }
810 
811 static struct uart_ops sunsab_pops = {
812 	.tx_empty	= sunsab_tx_empty,
813 	.set_mctrl	= sunsab_set_mctrl,
814 	.get_mctrl	= sunsab_get_mctrl,
815 	.stop_tx	= sunsab_stop_tx,
816 	.start_tx	= sunsab_start_tx,
817 	.send_xchar	= sunsab_send_xchar,
818 	.stop_rx	= sunsab_stop_rx,
819 	.break_ctl	= sunsab_break_ctl,
820 	.startup	= sunsab_startup,
821 	.shutdown	= sunsab_shutdown,
822 	.set_termios	= sunsab_set_termios,
823 	.type		= sunsab_type,
824 	.release_port	= sunsab_release_port,
825 	.request_port	= sunsab_request_port,
826 	.config_port	= sunsab_config_port,
827 	.verify_port	= sunsab_verify_port,
828 };
829 
830 static struct uart_driver sunsab_reg = {
831 	.owner			= THIS_MODULE,
832 	.driver_name		= "sunsab",
833 	.dev_name		= "ttyS",
834 	.major			= TTY_MAJOR,
835 };
836 
837 static struct uart_sunsab_port *sunsab_ports;
838 
839 #ifdef CONFIG_SERIAL_SUNSAB_CONSOLE
840 
841 static void sunsab_console_putchar(struct uart_port *port, int c)
842 {
843 	struct uart_sunsab_port *up = (struct uart_sunsab_port *)port;
844 
845 	sunsab_tec_wait(up);
846 	writeb(c, &up->regs->w.tic);
847 }
848 
849 static void sunsab_console_write(struct console *con, const char *s, unsigned n)
850 {
851 	struct uart_sunsab_port *up = &sunsab_ports[con->index];
852 	unsigned long flags;
853 	int locked = 1;
854 
855 	if (up->port.sysrq || oops_in_progress)
856 		locked = spin_trylock_irqsave(&up->port.lock, flags);
857 	else
858 		spin_lock_irqsave(&up->port.lock, flags);
859 
860 	uart_console_write(&up->port, s, n, sunsab_console_putchar);
861 	sunsab_tec_wait(up);
862 
863 	if (locked)
864 		spin_unlock_irqrestore(&up->port.lock, flags);
865 }
866 
867 static int sunsab_console_setup(struct console *con, char *options)
868 {
869 	struct uart_sunsab_port *up = &sunsab_ports[con->index];
870 	unsigned long flags;
871 	unsigned int baud, quot;
872 
873 	/*
874 	 * The console framework calls us for each and every port
875 	 * registered. Defer the console setup until the requested
876 	 * port has been properly discovered. A bit of a hack,
877 	 * though...
878 	 */
879 	if (up->port.type != PORT_SUNSAB)
880 		return -1;
881 
882 	printk("Console: ttyS%d (SAB82532)\n",
883 	       (sunsab_reg.minor - 64) + con->index);
884 
885 	sunserial_console_termios(con, up->port.dev->of_node);
886 
887 	switch (con->cflag & CBAUD) {
888 	case B150: baud = 150; break;
889 	case B300: baud = 300; break;
890 	case B600: baud = 600; break;
891 	case B1200: baud = 1200; break;
892 	case B2400: baud = 2400; break;
893 	case B4800: baud = 4800; break;
894 	default: case B9600: baud = 9600; break;
895 	case B19200: baud = 19200; break;
896 	case B38400: baud = 38400; break;
897 	case B57600: baud = 57600; break;
898 	case B115200: baud = 115200; break;
899 	case B230400: baud = 230400; break;
900 	case B460800: baud = 460800; break;
901 	}
902 
903 	/*
904 	 * Temporary fix.
905 	 */
906 	spin_lock_init(&up->port.lock);
907 
908 	/*
909 	 * Initialize the hardware
910 	 */
911 	sunsab_startup(&up->port);
912 
913 	spin_lock_irqsave(&up->port.lock, flags);
914 
915 	/*
916 	 * Finally, enable interrupts
917 	 */
918 	up->interrupt_mask0 = SAB82532_IMR0_PERR | SAB82532_IMR0_FERR |
919 				SAB82532_IMR0_PLLA | SAB82532_IMR0_CDSC;
920 	writeb(up->interrupt_mask0, &up->regs->w.imr0);
921 	up->interrupt_mask1 = SAB82532_IMR1_BRKT | SAB82532_IMR1_ALLS |
922 				SAB82532_IMR1_XOFF | SAB82532_IMR1_TIN |
923 				SAB82532_IMR1_CSC | SAB82532_IMR1_XON |
924 				SAB82532_IMR1_XPR;
925 	writeb(up->interrupt_mask1, &up->regs->w.imr1);
926 
927 	quot = uart_get_divisor(&up->port, baud);
928 	sunsab_convert_to_sab(up, con->cflag, 0, baud, quot);
929 	sunsab_set_mctrl(&up->port, TIOCM_DTR | TIOCM_RTS);
930 
931 	spin_unlock_irqrestore(&up->port.lock, flags);
932 
933 	return 0;
934 }
935 
936 static struct console sunsab_console = {
937 	.name	=	"ttyS",
938 	.write	=	sunsab_console_write,
939 	.device	=	uart_console_device,
940 	.setup	=	sunsab_console_setup,
941 	.flags	=	CON_PRINTBUFFER,
942 	.index	=	-1,
943 	.data	=	&sunsab_reg,
944 };
945 
946 static inline struct console *SUNSAB_CONSOLE(void)
947 {
948 	return &sunsab_console;
949 }
950 #else
951 #define SUNSAB_CONSOLE()	(NULL)
952 #define sunsab_console_init()	do { } while (0)
953 #endif
954 
955 static int sunsab_init_one(struct uart_sunsab_port *up,
956 				     struct platform_device *op,
957 				     unsigned long offset,
958 				     int line)
959 {
960 	up->port.line = line;
961 	up->port.dev = &op->dev;
962 
963 	up->port.mapbase = op->resource[0].start + offset;
964 	up->port.membase = of_ioremap(&op->resource[0], offset,
965 				      sizeof(union sab82532_async_regs),
966 				      "sab");
967 	if (!up->port.membase)
968 		return -ENOMEM;
969 	up->regs = (union sab82532_async_regs __iomem *) up->port.membase;
970 
971 	up->port.irq = op->archdata.irqs[0];
972 
973 	up->port.fifosize = SAB82532_XMIT_FIFO_SIZE;
974 	up->port.iotype = UPIO_MEM;
975 
976 	writeb(SAB82532_IPC_IC_ACT_LOW, &up->regs->w.ipc);
977 
978 	up->port.ops = &sunsab_pops;
979 	up->port.type = PORT_SUNSAB;
980 	up->port.uartclk = SAB_BASE_BAUD;
981 
982 	up->type = readb(&up->regs->r.vstr) & 0x0f;
983 	writeb(~((1 << 1) | (1 << 2) | (1 << 4)), &up->regs->w.pcr);
984 	writeb(0xff, &up->regs->w.pim);
985 	if ((up->port.line & 0x1) == 0) {
986 		up->pvr_dsr_bit = (1 << 0);
987 		up->pvr_dtr_bit = (1 << 1);
988 		up->gis_shift = 2;
989 	} else {
990 		up->pvr_dsr_bit = (1 << 3);
991 		up->pvr_dtr_bit = (1 << 2);
992 		up->gis_shift = 0;
993 	}
994 	up->cached_pvr = (1 << 1) | (1 << 2) | (1 << 4);
995 	writeb(up->cached_pvr, &up->regs->w.pvr);
996 	up->cached_mode = readb(&up->regs->rw.mode);
997 	up->cached_mode |= SAB82532_MODE_FRTS;
998 	writeb(up->cached_mode, &up->regs->rw.mode);
999 	up->cached_mode |= SAB82532_MODE_RTS;
1000 	writeb(up->cached_mode, &up->regs->rw.mode);
1001 
1002 	up->tec_timeout = SAB82532_MAX_TEC_TIMEOUT;
1003 	up->cec_timeout = SAB82532_MAX_CEC_TIMEOUT;
1004 
1005 	return 0;
1006 }
1007 
1008 static int sab_probe(struct platform_device *op)
1009 {
1010 	static int inst;
1011 	struct uart_sunsab_port *up;
1012 	int err;
1013 
1014 	up = &sunsab_ports[inst * 2];
1015 
1016 	err = sunsab_init_one(&up[0], op,
1017 			      0,
1018 			      (inst * 2) + 0);
1019 	if (err)
1020 		goto out;
1021 
1022 	err = sunsab_init_one(&up[1], op,
1023 			      sizeof(union sab82532_async_regs),
1024 			      (inst * 2) + 1);
1025 	if (err)
1026 		goto out1;
1027 
1028 	sunserial_console_match(SUNSAB_CONSOLE(), op->dev.of_node,
1029 				&sunsab_reg, up[0].port.line,
1030 				false);
1031 
1032 	sunserial_console_match(SUNSAB_CONSOLE(), op->dev.of_node,
1033 				&sunsab_reg, up[1].port.line,
1034 				false);
1035 
1036 	err = uart_add_one_port(&sunsab_reg, &up[0].port);
1037 	if (err)
1038 		goto out2;
1039 
1040 	err = uart_add_one_port(&sunsab_reg, &up[1].port);
1041 	if (err)
1042 		goto out3;
1043 
1044 	platform_set_drvdata(op, &up[0]);
1045 
1046 	inst++;
1047 
1048 	return 0;
1049 
1050 out3:
1051 	uart_remove_one_port(&sunsab_reg, &up[0].port);
1052 out2:
1053 	of_iounmap(&op->resource[0],
1054 		   up[1].port.membase,
1055 		   sizeof(union sab82532_async_regs));
1056 out1:
1057 	of_iounmap(&op->resource[0],
1058 		   up[0].port.membase,
1059 		   sizeof(union sab82532_async_regs));
1060 out:
1061 	return err;
1062 }
1063 
1064 static int sab_remove(struct platform_device *op)
1065 {
1066 	struct uart_sunsab_port *up = platform_get_drvdata(op);
1067 
1068 	uart_remove_one_port(&sunsab_reg, &up[1].port);
1069 	uart_remove_one_port(&sunsab_reg, &up[0].port);
1070 	of_iounmap(&op->resource[0],
1071 		   up[1].port.membase,
1072 		   sizeof(union sab82532_async_regs));
1073 	of_iounmap(&op->resource[0],
1074 		   up[0].port.membase,
1075 		   sizeof(union sab82532_async_regs));
1076 
1077 	return 0;
1078 }
1079 
1080 static const struct of_device_id sab_match[] = {
1081 	{
1082 		.name = "se",
1083 	},
1084 	{
1085 		.name = "serial",
1086 		.compatible = "sab82532",
1087 	},
1088 	{},
1089 };
1090 MODULE_DEVICE_TABLE(of, sab_match);
1091 
1092 static struct platform_driver sab_driver = {
1093 	.driver = {
1094 		.name = "sab",
1095 		.owner = THIS_MODULE,
1096 		.of_match_table = sab_match,
1097 	},
1098 	.probe		= sab_probe,
1099 	.remove		= sab_remove,
1100 };
1101 
1102 static int __init sunsab_init(void)
1103 {
1104 	struct device_node *dp;
1105 	int err;
1106 	int num_channels = 0;
1107 
1108 	for_each_node_by_name(dp, "se")
1109 		num_channels += 2;
1110 	for_each_node_by_name(dp, "serial") {
1111 		if (of_device_is_compatible(dp, "sab82532"))
1112 			num_channels += 2;
1113 	}
1114 
1115 	if (num_channels) {
1116 		sunsab_ports = kzalloc(sizeof(struct uart_sunsab_port) *
1117 				       num_channels, GFP_KERNEL);
1118 		if (!sunsab_ports)
1119 			return -ENOMEM;
1120 
1121 		err = sunserial_register_minors(&sunsab_reg, num_channels);
1122 		if (err) {
1123 			kfree(sunsab_ports);
1124 			sunsab_ports = NULL;
1125 
1126 			return err;
1127 		}
1128 	}
1129 
1130 	return platform_driver_register(&sab_driver);
1131 }
1132 
1133 static void __exit sunsab_exit(void)
1134 {
1135 	platform_driver_unregister(&sab_driver);
1136 	if (sunsab_reg.nr) {
1137 		sunserial_unregister_minors(&sunsab_reg, sunsab_reg.nr);
1138 	}
1139 
1140 	kfree(sunsab_ports);
1141 	sunsab_ports = NULL;
1142 }
1143 
1144 module_init(sunsab_init);
1145 module_exit(sunsab_exit);
1146 
1147 MODULE_AUTHOR("Eddie C. Dost and David S. Miller");
1148 MODULE_DESCRIPTION("Sun SAB82532 serial port driver");
1149 MODULE_LICENSE("GPL");
1150