xref: /openbmc/linux/drivers/tty/serial/sunsab.c (revision afb46f79)
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 	for (i = 0; i < count; i++) {
161 		unsigned char ch = buf[i], flag;
162 
163 		flag = TTY_NORMAL;
164 		up->port.icount.rx++;
165 
166 		if (unlikely(stat->sreg.isr0 & (SAB82532_ISR0_PERR |
167 						SAB82532_ISR0_FERR |
168 						SAB82532_ISR0_RFO)) ||
169 		    unlikely(stat->sreg.isr1 & SAB82532_ISR1_BRK)) {
170 			/*
171 			 * For statistics only
172 			 */
173 			if (stat->sreg.isr1 & SAB82532_ISR1_BRK) {
174 				stat->sreg.isr0 &= ~(SAB82532_ISR0_PERR |
175 						     SAB82532_ISR0_FERR);
176 				up->port.icount.brk++;
177 				/*
178 				 * We do the SysRQ and SAK checking
179 				 * here because otherwise the break
180 				 * may get masked by ignore_status_mask
181 				 * or read_status_mask.
182 				 */
183 				if (uart_handle_break(&up->port))
184 					continue;
185 			} else if (stat->sreg.isr0 & SAB82532_ISR0_PERR)
186 				up->port.icount.parity++;
187 			else if (stat->sreg.isr0 & SAB82532_ISR0_FERR)
188 				up->port.icount.frame++;
189 			if (stat->sreg.isr0 & SAB82532_ISR0_RFO)
190 				up->port.icount.overrun++;
191 
192 			/*
193 			 * Mask off conditions which should be ingored.
194 			 */
195 			stat->sreg.isr0 &= (up->port.read_status_mask & 0xff);
196 			stat->sreg.isr1 &= ((up->port.read_status_mask >> 8) & 0xff);
197 
198 			if (stat->sreg.isr1 & SAB82532_ISR1_BRK) {
199 				flag = TTY_BREAK;
200 			} else if (stat->sreg.isr0 & SAB82532_ISR0_PERR)
201 				flag = TTY_PARITY;
202 			else if (stat->sreg.isr0 & SAB82532_ISR0_FERR)
203 				flag = TTY_FRAME;
204 		}
205 
206 		if (uart_handle_sysrq_char(&up->port, ch) || !port)
207 			continue;
208 
209 		if ((stat->sreg.isr0 & (up->port.ignore_status_mask & 0xff)) == 0 &&
210 		    (stat->sreg.isr1 & ((up->port.ignore_status_mask >> 8) & 0xff)) == 0)
211 			tty_insert_flip_char(port, ch, flag);
212 		if (stat->sreg.isr0 & SAB82532_ISR0_RFO)
213 			tty_insert_flip_char(port, 0, TTY_OVERRUN);
214 	}
215 
216 	if (saw_console_brk)
217 		sun_do_break();
218 
219 	return port;
220 }
221 
222 static void sunsab_stop_tx(struct uart_port *);
223 static void sunsab_tx_idle(struct uart_sunsab_port *);
224 
225 static void transmit_chars(struct uart_sunsab_port *up,
226 			   union sab82532_irq_status *stat)
227 {
228 	struct circ_buf *xmit = &up->port.state->xmit;
229 	int i;
230 
231 	if (stat->sreg.isr1 & SAB82532_ISR1_ALLS) {
232 		up->interrupt_mask1 |= SAB82532_IMR1_ALLS;
233 		writeb(up->interrupt_mask1, &up->regs->w.imr1);
234 		set_bit(SAB82532_ALLS, &up->irqflags);
235 	}
236 
237 #if 0 /* bde@nwlink.com says this check causes problems */
238 	if (!(stat->sreg.isr1 & SAB82532_ISR1_XPR))
239 		return;
240 #endif
241 
242 	if (!(readb(&up->regs->r.star) & SAB82532_STAR_XFW))
243 		return;
244 
245 	set_bit(SAB82532_XPR, &up->irqflags);
246 	sunsab_tx_idle(up);
247 
248 	if (uart_circ_empty(xmit) || uart_tx_stopped(&up->port)) {
249 		up->interrupt_mask1 |= SAB82532_IMR1_XPR;
250 		writeb(up->interrupt_mask1, &up->regs->w.imr1);
251 		return;
252 	}
253 
254 	up->interrupt_mask1 &= ~(SAB82532_IMR1_ALLS|SAB82532_IMR1_XPR);
255 	writeb(up->interrupt_mask1, &up->regs->w.imr1);
256 	clear_bit(SAB82532_ALLS, &up->irqflags);
257 
258 	/* Stuff 32 bytes into Transmit FIFO. */
259 	clear_bit(SAB82532_XPR, &up->irqflags);
260 	for (i = 0; i < up->port.fifosize; i++) {
261 		writeb(xmit->buf[xmit->tail],
262 		       &up->regs->w.xfifo[i]);
263 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
264 		up->port.icount.tx++;
265 		if (uart_circ_empty(xmit))
266 			break;
267 	}
268 
269 	/* Issue a Transmit Frame command. */
270 	sunsab_cec_wait(up);
271 	writeb(SAB82532_CMDR_XF, &up->regs->w.cmdr);
272 
273 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
274 		uart_write_wakeup(&up->port);
275 
276 	if (uart_circ_empty(xmit))
277 		sunsab_stop_tx(&up->port);
278 }
279 
280 static void check_status(struct uart_sunsab_port *up,
281 			 union sab82532_irq_status *stat)
282 {
283 	if (stat->sreg.isr0 & SAB82532_ISR0_CDSC)
284 		uart_handle_dcd_change(&up->port,
285 				       !(readb(&up->regs->r.vstr) & SAB82532_VSTR_CD));
286 
287 	if (stat->sreg.isr1 & SAB82532_ISR1_CSC)
288 		uart_handle_cts_change(&up->port,
289 				       (readb(&up->regs->r.star) & SAB82532_STAR_CTS));
290 
291 	if ((readb(&up->regs->r.pvr) & up->pvr_dsr_bit) ^ up->dsr) {
292 		up->dsr = (readb(&up->regs->r.pvr) & up->pvr_dsr_bit) ? 0 : 1;
293 		up->port.icount.dsr++;
294 	}
295 
296 	wake_up_interruptible(&up->port.state->port.delta_msr_wait);
297 }
298 
299 static irqreturn_t sunsab_interrupt(int irq, void *dev_id)
300 {
301 	struct uart_sunsab_port *up = dev_id;
302 	struct tty_port *port = NULL;
303 	union sab82532_irq_status status;
304 	unsigned long flags;
305 	unsigned char gis;
306 
307 	spin_lock_irqsave(&up->port.lock, flags);
308 
309 	status.stat = 0;
310 	gis = readb(&up->regs->r.gis) >> up->gis_shift;
311 	if (gis & 1)
312 		status.sreg.isr0 = readb(&up->regs->r.isr0);
313 	if (gis & 2)
314 		status.sreg.isr1 = readb(&up->regs->r.isr1);
315 
316 	if (status.stat) {
317 		if ((status.sreg.isr0 & (SAB82532_ISR0_TCD | SAB82532_ISR0_TIME |
318 					 SAB82532_ISR0_RFO | SAB82532_ISR0_RPF)) ||
319 		    (status.sreg.isr1 & SAB82532_ISR1_BRK))
320 			port = receive_chars(up, &status);
321 		if ((status.sreg.isr0 & SAB82532_ISR0_CDSC) ||
322 		    (status.sreg.isr1 & SAB82532_ISR1_CSC))
323 			check_status(up, &status);
324 		if (status.sreg.isr1 & (SAB82532_ISR1_ALLS | SAB82532_ISR1_XPR))
325 			transmit_chars(up, &status);
326 	}
327 
328 	spin_unlock_irqrestore(&up->port.lock, flags);
329 
330 	if (port)
331 		tty_flip_buffer_push(port);
332 
333 	return IRQ_HANDLED;
334 }
335 
336 /* port->lock is not held.  */
337 static unsigned int sunsab_tx_empty(struct uart_port *port)
338 {
339 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
340 	int ret;
341 
342 	/* Do not need a lock for a state test like this.  */
343 	if (test_bit(SAB82532_ALLS, &up->irqflags))
344 		ret = TIOCSER_TEMT;
345 	else
346 		ret = 0;
347 
348 	return ret;
349 }
350 
351 /* port->lock held by caller.  */
352 static void sunsab_set_mctrl(struct uart_port *port, unsigned int mctrl)
353 {
354 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
355 
356 	if (mctrl & TIOCM_RTS) {
357 		up->cached_mode &= ~SAB82532_MODE_FRTS;
358 		up->cached_mode |= SAB82532_MODE_RTS;
359 	} else {
360 		up->cached_mode |= (SAB82532_MODE_FRTS |
361 				    SAB82532_MODE_RTS);
362 	}
363 	if (mctrl & TIOCM_DTR) {
364 		up->cached_pvr &= ~(up->pvr_dtr_bit);
365 	} else {
366 		up->cached_pvr |= up->pvr_dtr_bit;
367 	}
368 
369 	set_bit(SAB82532_REGS_PENDING, &up->irqflags);
370 	if (test_bit(SAB82532_XPR, &up->irqflags))
371 		sunsab_tx_idle(up);
372 }
373 
374 /* port->lock is held by caller and interrupts are disabled.  */
375 static unsigned int sunsab_get_mctrl(struct uart_port *port)
376 {
377 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
378 	unsigned char val;
379 	unsigned int result;
380 
381 	result = 0;
382 
383 	val = readb(&up->regs->r.pvr);
384 	result |= (val & up->pvr_dsr_bit) ? 0 : TIOCM_DSR;
385 
386 	val = readb(&up->regs->r.vstr);
387 	result |= (val & SAB82532_VSTR_CD) ? 0 : TIOCM_CAR;
388 
389 	val = readb(&up->regs->r.star);
390 	result |= (val & SAB82532_STAR_CTS) ? TIOCM_CTS : 0;
391 
392 	return result;
393 }
394 
395 /* port->lock held by caller.  */
396 static void sunsab_stop_tx(struct uart_port *port)
397 {
398 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
399 
400 	up->interrupt_mask1 |= SAB82532_IMR1_XPR;
401 	writeb(up->interrupt_mask1, &up->regs->w.imr1);
402 }
403 
404 /* port->lock held by caller.  */
405 static void sunsab_tx_idle(struct uart_sunsab_port *up)
406 {
407 	if (test_bit(SAB82532_REGS_PENDING, &up->irqflags)) {
408 		u8 tmp;
409 
410 		clear_bit(SAB82532_REGS_PENDING, &up->irqflags);
411 		writeb(up->cached_mode, &up->regs->rw.mode);
412 		writeb(up->cached_pvr, &up->regs->rw.pvr);
413 		writeb(up->cached_dafo, &up->regs->w.dafo);
414 
415 		writeb(up->cached_ebrg & 0xff, &up->regs->w.bgr);
416 		tmp = readb(&up->regs->rw.ccr2);
417 		tmp &= ~0xc0;
418 		tmp |= (up->cached_ebrg >> 2) & 0xc0;
419 		writeb(tmp, &up->regs->rw.ccr2);
420 	}
421 }
422 
423 /* port->lock held by caller.  */
424 static void sunsab_start_tx(struct uart_port *port)
425 {
426 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
427 	struct circ_buf *xmit = &up->port.state->xmit;
428 	int i;
429 
430 	up->interrupt_mask1 &= ~(SAB82532_IMR1_ALLS|SAB82532_IMR1_XPR);
431 	writeb(up->interrupt_mask1, &up->regs->w.imr1);
432 
433 	if (!test_bit(SAB82532_XPR, &up->irqflags))
434 		return;
435 
436 	clear_bit(SAB82532_ALLS, &up->irqflags);
437 	clear_bit(SAB82532_XPR, &up->irqflags);
438 
439 	for (i = 0; i < up->port.fifosize; i++) {
440 		writeb(xmit->buf[xmit->tail],
441 		       &up->regs->w.xfifo[i]);
442 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
443 		up->port.icount.tx++;
444 		if (uart_circ_empty(xmit))
445 			break;
446 	}
447 
448 	/* Issue a Transmit Frame command.  */
449 	sunsab_cec_wait(up);
450 	writeb(SAB82532_CMDR_XF, &up->regs->w.cmdr);
451 }
452 
453 /* port->lock is not held.  */
454 static void sunsab_send_xchar(struct uart_port *port, char ch)
455 {
456 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
457 	unsigned long flags;
458 
459 	spin_lock_irqsave(&up->port.lock, flags);
460 
461 	sunsab_tec_wait(up);
462 	writeb(ch, &up->regs->w.tic);
463 
464 	spin_unlock_irqrestore(&up->port.lock, flags);
465 }
466 
467 /* port->lock held by caller.  */
468 static void sunsab_stop_rx(struct uart_port *port)
469 {
470 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
471 
472 	up->interrupt_mask0 |= SAB82532_IMR0_TCD;
473 	writeb(up->interrupt_mask1, &up->regs->w.imr0);
474 }
475 
476 /* port->lock held by caller.  */
477 static void sunsab_enable_ms(struct uart_port *port)
478 {
479 	/* For now we always receive these interrupts.  */
480 }
481 
482 /* port->lock is not held.  */
483 static void sunsab_break_ctl(struct uart_port *port, int break_state)
484 {
485 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
486 	unsigned long flags;
487 	unsigned char val;
488 
489 	spin_lock_irqsave(&up->port.lock, flags);
490 
491 	val = up->cached_dafo;
492 	if (break_state)
493 		val |= SAB82532_DAFO_XBRK;
494 	else
495 		val &= ~SAB82532_DAFO_XBRK;
496 	up->cached_dafo = val;
497 
498 	set_bit(SAB82532_REGS_PENDING, &up->irqflags);
499 	if (test_bit(SAB82532_XPR, &up->irqflags))
500 		sunsab_tx_idle(up);
501 
502 	spin_unlock_irqrestore(&up->port.lock, flags);
503 }
504 
505 /* port->lock is not held.  */
506 static int sunsab_startup(struct uart_port *port)
507 {
508 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
509 	unsigned long flags;
510 	unsigned char tmp;
511 	int err = request_irq(up->port.irq, sunsab_interrupt,
512 			      IRQF_SHARED, "sab", up);
513 	if (err)
514 		return err;
515 
516 	spin_lock_irqsave(&up->port.lock, flags);
517 
518 	/*
519 	 * Wait for any commands or immediate characters
520 	 */
521 	sunsab_cec_wait(up);
522 	sunsab_tec_wait(up);
523 
524 	/*
525 	 * Clear the FIFO buffers.
526 	 */
527 	writeb(SAB82532_CMDR_RRES, &up->regs->w.cmdr);
528 	sunsab_cec_wait(up);
529 	writeb(SAB82532_CMDR_XRES, &up->regs->w.cmdr);
530 
531 	/*
532 	 * Clear the interrupt registers.
533 	 */
534 	(void) readb(&up->regs->r.isr0);
535 	(void) readb(&up->regs->r.isr1);
536 
537 	/*
538 	 * Now, initialize the UART
539 	 */
540 	writeb(0, &up->regs->w.ccr0);				/* power-down */
541 	writeb(SAB82532_CCR0_MCE | SAB82532_CCR0_SC_NRZ |
542 	       SAB82532_CCR0_SM_ASYNC, &up->regs->w.ccr0);
543 	writeb(SAB82532_CCR1_ODS | SAB82532_CCR1_BCR | 7, &up->regs->w.ccr1);
544 	writeb(SAB82532_CCR2_BDF | SAB82532_CCR2_SSEL |
545 	       SAB82532_CCR2_TOE, &up->regs->w.ccr2);
546 	writeb(0, &up->regs->w.ccr3);
547 	writeb(SAB82532_CCR4_MCK4 | SAB82532_CCR4_EBRG, &up->regs->w.ccr4);
548 	up->cached_mode = (SAB82532_MODE_RTS | SAB82532_MODE_FCTS |
549 			   SAB82532_MODE_RAC);
550 	writeb(up->cached_mode, &up->regs->w.mode);
551 	writeb(SAB82532_RFC_DPS|SAB82532_RFC_RFTH_32, &up->regs->w.rfc);
552 
553 	tmp = readb(&up->regs->rw.ccr0);
554 	tmp |= SAB82532_CCR0_PU;	/* power-up */
555 	writeb(tmp, &up->regs->rw.ccr0);
556 
557 	/*
558 	 * Finally, enable interrupts
559 	 */
560 	up->interrupt_mask0 = (SAB82532_IMR0_PERR | SAB82532_IMR0_FERR |
561 			       SAB82532_IMR0_PLLA);
562 	writeb(up->interrupt_mask0, &up->regs->w.imr0);
563 	up->interrupt_mask1 = (SAB82532_IMR1_BRKT | SAB82532_IMR1_ALLS |
564 			       SAB82532_IMR1_XOFF | SAB82532_IMR1_TIN |
565 			       SAB82532_IMR1_CSC | SAB82532_IMR1_XON |
566 			       SAB82532_IMR1_XPR);
567 	writeb(up->interrupt_mask1, &up->regs->w.imr1);
568 	set_bit(SAB82532_ALLS, &up->irqflags);
569 	set_bit(SAB82532_XPR, &up->irqflags);
570 
571 	spin_unlock_irqrestore(&up->port.lock, flags);
572 
573 	return 0;
574 }
575 
576 /* port->lock is not held.  */
577 static void sunsab_shutdown(struct uart_port *port)
578 {
579 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
580 	unsigned long flags;
581 
582 	spin_lock_irqsave(&up->port.lock, flags);
583 
584 	/* Disable Interrupts */
585 	up->interrupt_mask0 = 0xff;
586 	writeb(up->interrupt_mask0, &up->regs->w.imr0);
587 	up->interrupt_mask1 = 0xff;
588 	writeb(up->interrupt_mask1, &up->regs->w.imr1);
589 
590 	/* Disable break condition */
591 	up->cached_dafo = readb(&up->regs->rw.dafo);
592 	up->cached_dafo &= ~SAB82532_DAFO_XBRK;
593 	writeb(up->cached_dafo, &up->regs->rw.dafo);
594 
595 	/* Disable Receiver */
596 	up->cached_mode &= ~SAB82532_MODE_RAC;
597 	writeb(up->cached_mode, &up->regs->rw.mode);
598 
599 	/*
600 	 * XXX FIXME
601 	 *
602 	 * If the chip is powered down here the system hangs/crashes during
603 	 * reboot or shutdown.  This needs to be investigated further,
604 	 * similar behaviour occurs in 2.4 when the driver is configured
605 	 * as a module only.  One hint may be that data is sometimes
606 	 * transmitted at 9600 baud during shutdown (regardless of the
607 	 * speed the chip was configured for when the port was open).
608 	 */
609 #if 0
610 	/* Power Down */
611 	tmp = readb(&up->regs->rw.ccr0);
612 	tmp &= ~SAB82532_CCR0_PU;
613 	writeb(tmp, &up->regs->rw.ccr0);
614 #endif
615 
616 	spin_unlock_irqrestore(&up->port.lock, flags);
617 	free_irq(up->port.irq, up);
618 }
619 
620 /*
621  * This is used to figure out the divisor speeds.
622  *
623  * The formula is:    Baud = SAB_BASE_BAUD / ((N + 1) * (1 << M)),
624  *
625  * with               0 <= N < 64 and 0 <= M < 16
626  */
627 
628 static void calc_ebrg(int baud, int *n_ret, int *m_ret)
629 {
630 	int	n, m;
631 
632 	if (baud == 0) {
633 		*n_ret = 0;
634 		*m_ret = 0;
635 		return;
636 	}
637 
638 	/*
639 	 * We scale numbers by 10 so that we get better accuracy
640 	 * without having to use floating point.  Here we increment m
641 	 * until n is within the valid range.
642 	 */
643 	n = (SAB_BASE_BAUD * 10) / baud;
644 	m = 0;
645 	while (n >= 640) {
646 		n = n / 2;
647 		m++;
648 	}
649 	n = (n+5) / 10;
650 	/*
651 	 * We try very hard to avoid speeds with M == 0 since they may
652 	 * not work correctly for XTAL frequences above 10 MHz.
653 	 */
654 	if ((m == 0) && ((n & 1) == 0)) {
655 		n = n / 2;
656 		m++;
657 	}
658 	*n_ret = n - 1;
659 	*m_ret = m;
660 }
661 
662 /* Internal routine, port->lock is held and local interrupts are disabled.  */
663 static void sunsab_convert_to_sab(struct uart_sunsab_port *up, unsigned int cflag,
664 				  unsigned int iflag, unsigned int baud,
665 				  unsigned int quot)
666 {
667 	unsigned char dafo;
668 	int bits, n, m;
669 
670 	/* Byte size and parity */
671 	switch (cflag & CSIZE) {
672 	      case CS5: dafo = SAB82532_DAFO_CHL5; bits = 7; break;
673 	      case CS6: dafo = SAB82532_DAFO_CHL6; bits = 8; break;
674 	      case CS7: dafo = SAB82532_DAFO_CHL7; bits = 9; break;
675 	      case CS8: dafo = SAB82532_DAFO_CHL8; bits = 10; break;
676 	      /* Never happens, but GCC is too dumb to figure it out */
677 	      default:  dafo = SAB82532_DAFO_CHL5; bits = 7; break;
678 	}
679 
680 	if (cflag & CSTOPB) {
681 		dafo |= SAB82532_DAFO_STOP;
682 		bits++;
683 	}
684 
685 	if (cflag & PARENB) {
686 		dafo |= SAB82532_DAFO_PARE;
687 		bits++;
688 	}
689 
690 	if (cflag & PARODD) {
691 		dafo |= SAB82532_DAFO_PAR_ODD;
692 	} else {
693 		dafo |= SAB82532_DAFO_PAR_EVEN;
694 	}
695 	up->cached_dafo = dafo;
696 
697 	calc_ebrg(baud, &n, &m);
698 
699 	up->cached_ebrg = n | (m << 6);
700 
701 	up->tec_timeout = (10 * 1000000) / baud;
702 	up->cec_timeout = up->tec_timeout >> 2;
703 
704 	/* CTS flow control flags */
705 	/* We encode read_status_mask and ignore_status_mask like so:
706 	 *
707 	 * ---------------------
708 	 * | ... | ISR1 | ISR0 |
709 	 * ---------------------
710 	 *  ..    15   8 7    0
711 	 */
712 
713 	up->port.read_status_mask = (SAB82532_ISR0_TCD | SAB82532_ISR0_TIME |
714 				     SAB82532_ISR0_RFO | SAB82532_ISR0_RPF |
715 				     SAB82532_ISR0_CDSC);
716 	up->port.read_status_mask |= (SAB82532_ISR1_CSC |
717 				      SAB82532_ISR1_ALLS |
718 				      SAB82532_ISR1_XPR) << 8;
719 	if (iflag & INPCK)
720 		up->port.read_status_mask |= (SAB82532_ISR0_PERR |
721 					      SAB82532_ISR0_FERR);
722 	if (iflag & (BRKINT | PARMRK))
723 		up->port.read_status_mask |= (SAB82532_ISR1_BRK << 8);
724 
725 	/*
726 	 * Characteres to ignore
727 	 */
728 	up->port.ignore_status_mask = 0;
729 	if (iflag & IGNPAR)
730 		up->port.ignore_status_mask |= (SAB82532_ISR0_PERR |
731 						SAB82532_ISR0_FERR);
732 	if (iflag & IGNBRK) {
733 		up->port.ignore_status_mask |= (SAB82532_ISR1_BRK << 8);
734 		/*
735 		 * If we're ignoring parity and break indicators,
736 		 * ignore overruns too (for real raw support).
737 		 */
738 		if (iflag & IGNPAR)
739 			up->port.ignore_status_mask |= SAB82532_ISR0_RFO;
740 	}
741 
742 	/*
743 	 * ignore all characters if CREAD is not set
744 	 */
745 	if ((cflag & CREAD) == 0)
746 		up->port.ignore_status_mask |= (SAB82532_ISR0_RPF |
747 						SAB82532_ISR0_TCD);
748 
749 	uart_update_timeout(&up->port, cflag,
750 			    (up->port.uartclk / (16 * quot)));
751 
752 	/* Now schedule a register update when the chip's
753 	 * transmitter is idle.
754 	 */
755 	up->cached_mode |= SAB82532_MODE_RAC;
756 	set_bit(SAB82532_REGS_PENDING, &up->irqflags);
757 	if (test_bit(SAB82532_XPR, &up->irqflags))
758 		sunsab_tx_idle(up);
759 }
760 
761 /* port->lock is not held.  */
762 static void sunsab_set_termios(struct uart_port *port, struct ktermios *termios,
763 			       struct ktermios *old)
764 {
765 	struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
766 	unsigned long flags;
767 	unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
768 	unsigned int quot = uart_get_divisor(port, baud);
769 
770 	spin_lock_irqsave(&up->port.lock, flags);
771 	sunsab_convert_to_sab(up, termios->c_cflag, termios->c_iflag, baud, quot);
772 	spin_unlock_irqrestore(&up->port.lock, flags);
773 }
774 
775 static const char *sunsab_type(struct uart_port *port)
776 {
777 	struct uart_sunsab_port *up = (void *)port;
778 	static char buf[36];
779 
780 	sprintf(buf, "SAB82532 %s", sab82532_version[up->type]);
781 	return buf;
782 }
783 
784 static void sunsab_release_port(struct uart_port *port)
785 {
786 }
787 
788 static int sunsab_request_port(struct uart_port *port)
789 {
790 	return 0;
791 }
792 
793 static void sunsab_config_port(struct uart_port *port, int flags)
794 {
795 }
796 
797 static int sunsab_verify_port(struct uart_port *port, struct serial_struct *ser)
798 {
799 	return -EINVAL;
800 }
801 
802 static struct uart_ops sunsab_pops = {
803 	.tx_empty	= sunsab_tx_empty,
804 	.set_mctrl	= sunsab_set_mctrl,
805 	.get_mctrl	= sunsab_get_mctrl,
806 	.stop_tx	= sunsab_stop_tx,
807 	.start_tx	= sunsab_start_tx,
808 	.send_xchar	= sunsab_send_xchar,
809 	.stop_rx	= sunsab_stop_rx,
810 	.enable_ms	= sunsab_enable_ms,
811 	.break_ctl	= sunsab_break_ctl,
812 	.startup	= sunsab_startup,
813 	.shutdown	= sunsab_shutdown,
814 	.set_termios	= sunsab_set_termios,
815 	.type		= sunsab_type,
816 	.release_port	= sunsab_release_port,
817 	.request_port	= sunsab_request_port,
818 	.config_port	= sunsab_config_port,
819 	.verify_port	= sunsab_verify_port,
820 };
821 
822 static struct uart_driver sunsab_reg = {
823 	.owner			= THIS_MODULE,
824 	.driver_name		= "sunsab",
825 	.dev_name		= "ttyS",
826 	.major			= TTY_MAJOR,
827 };
828 
829 static struct uart_sunsab_port *sunsab_ports;
830 
831 #ifdef CONFIG_SERIAL_SUNSAB_CONSOLE
832 
833 static void sunsab_console_putchar(struct uart_port *port, int c)
834 {
835 	struct uart_sunsab_port *up = (struct uart_sunsab_port *)port;
836 
837 	sunsab_tec_wait(up);
838 	writeb(c, &up->regs->w.tic);
839 }
840 
841 static void sunsab_console_write(struct console *con, const char *s, unsigned n)
842 {
843 	struct uart_sunsab_port *up = &sunsab_ports[con->index];
844 	unsigned long flags;
845 	int locked = 1;
846 
847 	if (up->port.sysrq || oops_in_progress)
848 		locked = spin_trylock_irqsave(&up->port.lock, flags);
849 	else
850 		spin_lock_irqsave(&up->port.lock, flags);
851 
852 	uart_console_write(&up->port, s, n, sunsab_console_putchar);
853 	sunsab_tec_wait(up);
854 
855 	if (locked)
856 		spin_unlock_irqrestore(&up->port.lock, flags);
857 }
858 
859 static int sunsab_console_setup(struct console *con, char *options)
860 {
861 	struct uart_sunsab_port *up = &sunsab_ports[con->index];
862 	unsigned long flags;
863 	unsigned int baud, quot;
864 
865 	/*
866 	 * The console framework calls us for each and every port
867 	 * registered. Defer the console setup until the requested
868 	 * port has been properly discovered. A bit of a hack,
869 	 * though...
870 	 */
871 	if (up->port.type != PORT_SUNSAB)
872 		return -1;
873 
874 	printk("Console: ttyS%d (SAB82532)\n",
875 	       (sunsab_reg.minor - 64) + con->index);
876 
877 	sunserial_console_termios(con, up->port.dev->of_node);
878 
879 	switch (con->cflag & CBAUD) {
880 	case B150: baud = 150; break;
881 	case B300: baud = 300; break;
882 	case B600: baud = 600; break;
883 	case B1200: baud = 1200; break;
884 	case B2400: baud = 2400; break;
885 	case B4800: baud = 4800; break;
886 	default: case B9600: baud = 9600; break;
887 	case B19200: baud = 19200; break;
888 	case B38400: baud = 38400; break;
889 	case B57600: baud = 57600; break;
890 	case B115200: baud = 115200; break;
891 	case B230400: baud = 230400; break;
892 	case B460800: baud = 460800; break;
893 	}
894 
895 	/*
896 	 * Temporary fix.
897 	 */
898 	spin_lock_init(&up->port.lock);
899 
900 	/*
901 	 * Initialize the hardware
902 	 */
903 	sunsab_startup(&up->port);
904 
905 	spin_lock_irqsave(&up->port.lock, flags);
906 
907 	/*
908 	 * Finally, enable interrupts
909 	 */
910 	up->interrupt_mask0 = SAB82532_IMR0_PERR | SAB82532_IMR0_FERR |
911 				SAB82532_IMR0_PLLA | SAB82532_IMR0_CDSC;
912 	writeb(up->interrupt_mask0, &up->regs->w.imr0);
913 	up->interrupt_mask1 = SAB82532_IMR1_BRKT | SAB82532_IMR1_ALLS |
914 				SAB82532_IMR1_XOFF | SAB82532_IMR1_TIN |
915 				SAB82532_IMR1_CSC | SAB82532_IMR1_XON |
916 				SAB82532_IMR1_XPR;
917 	writeb(up->interrupt_mask1, &up->regs->w.imr1);
918 
919 	quot = uart_get_divisor(&up->port, baud);
920 	sunsab_convert_to_sab(up, con->cflag, 0, baud, quot);
921 	sunsab_set_mctrl(&up->port, TIOCM_DTR | TIOCM_RTS);
922 
923 	spin_unlock_irqrestore(&up->port.lock, flags);
924 
925 	return 0;
926 }
927 
928 static struct console sunsab_console = {
929 	.name	=	"ttyS",
930 	.write	=	sunsab_console_write,
931 	.device	=	uart_console_device,
932 	.setup	=	sunsab_console_setup,
933 	.flags	=	CON_PRINTBUFFER,
934 	.index	=	-1,
935 	.data	=	&sunsab_reg,
936 };
937 
938 static inline struct console *SUNSAB_CONSOLE(void)
939 {
940 	return &sunsab_console;
941 }
942 #else
943 #define SUNSAB_CONSOLE()	(NULL)
944 #define sunsab_console_init()	do { } while (0)
945 #endif
946 
947 static int sunsab_init_one(struct uart_sunsab_port *up,
948 				     struct platform_device *op,
949 				     unsigned long offset,
950 				     int line)
951 {
952 	up->port.line = line;
953 	up->port.dev = &op->dev;
954 
955 	up->port.mapbase = op->resource[0].start + offset;
956 	up->port.membase = of_ioremap(&op->resource[0], offset,
957 				      sizeof(union sab82532_async_regs),
958 				      "sab");
959 	if (!up->port.membase)
960 		return -ENOMEM;
961 	up->regs = (union sab82532_async_regs __iomem *) up->port.membase;
962 
963 	up->port.irq = op->archdata.irqs[0];
964 
965 	up->port.fifosize = SAB82532_XMIT_FIFO_SIZE;
966 	up->port.iotype = UPIO_MEM;
967 
968 	writeb(SAB82532_IPC_IC_ACT_LOW, &up->regs->w.ipc);
969 
970 	up->port.ops = &sunsab_pops;
971 	up->port.type = PORT_SUNSAB;
972 	up->port.uartclk = SAB_BASE_BAUD;
973 
974 	up->type = readb(&up->regs->r.vstr) & 0x0f;
975 	writeb(~((1 << 1) | (1 << 2) | (1 << 4)), &up->regs->w.pcr);
976 	writeb(0xff, &up->regs->w.pim);
977 	if ((up->port.line & 0x1) == 0) {
978 		up->pvr_dsr_bit = (1 << 0);
979 		up->pvr_dtr_bit = (1 << 1);
980 		up->gis_shift = 2;
981 	} else {
982 		up->pvr_dsr_bit = (1 << 3);
983 		up->pvr_dtr_bit = (1 << 2);
984 		up->gis_shift = 0;
985 	}
986 	up->cached_pvr = (1 << 1) | (1 << 2) | (1 << 4);
987 	writeb(up->cached_pvr, &up->regs->w.pvr);
988 	up->cached_mode = readb(&up->regs->rw.mode);
989 	up->cached_mode |= SAB82532_MODE_FRTS;
990 	writeb(up->cached_mode, &up->regs->rw.mode);
991 	up->cached_mode |= SAB82532_MODE_RTS;
992 	writeb(up->cached_mode, &up->regs->rw.mode);
993 
994 	up->tec_timeout = SAB82532_MAX_TEC_TIMEOUT;
995 	up->cec_timeout = SAB82532_MAX_CEC_TIMEOUT;
996 
997 	return 0;
998 }
999 
1000 static int sab_probe(struct platform_device *op)
1001 {
1002 	static int inst;
1003 	struct uart_sunsab_port *up;
1004 	int err;
1005 
1006 	up = &sunsab_ports[inst * 2];
1007 
1008 	err = sunsab_init_one(&up[0], op,
1009 			      0,
1010 			      (inst * 2) + 0);
1011 	if (err)
1012 		goto out;
1013 
1014 	err = sunsab_init_one(&up[1], op,
1015 			      sizeof(union sab82532_async_regs),
1016 			      (inst * 2) + 1);
1017 	if (err)
1018 		goto out1;
1019 
1020 	sunserial_console_match(SUNSAB_CONSOLE(), op->dev.of_node,
1021 				&sunsab_reg, up[0].port.line,
1022 				false);
1023 
1024 	sunserial_console_match(SUNSAB_CONSOLE(), op->dev.of_node,
1025 				&sunsab_reg, up[1].port.line,
1026 				false);
1027 
1028 	err = uart_add_one_port(&sunsab_reg, &up[0].port);
1029 	if (err)
1030 		goto out2;
1031 
1032 	err = uart_add_one_port(&sunsab_reg, &up[1].port);
1033 	if (err)
1034 		goto out3;
1035 
1036 	platform_set_drvdata(op, &up[0]);
1037 
1038 	inst++;
1039 
1040 	return 0;
1041 
1042 out3:
1043 	uart_remove_one_port(&sunsab_reg, &up[0].port);
1044 out2:
1045 	of_iounmap(&op->resource[0],
1046 		   up[1].port.membase,
1047 		   sizeof(union sab82532_async_regs));
1048 out1:
1049 	of_iounmap(&op->resource[0],
1050 		   up[0].port.membase,
1051 		   sizeof(union sab82532_async_regs));
1052 out:
1053 	return err;
1054 }
1055 
1056 static int sab_remove(struct platform_device *op)
1057 {
1058 	struct uart_sunsab_port *up = platform_get_drvdata(op);
1059 
1060 	uart_remove_one_port(&sunsab_reg, &up[1].port);
1061 	uart_remove_one_port(&sunsab_reg, &up[0].port);
1062 	of_iounmap(&op->resource[0],
1063 		   up[1].port.membase,
1064 		   sizeof(union sab82532_async_regs));
1065 	of_iounmap(&op->resource[0],
1066 		   up[0].port.membase,
1067 		   sizeof(union sab82532_async_regs));
1068 
1069 	return 0;
1070 }
1071 
1072 static const struct of_device_id sab_match[] = {
1073 	{
1074 		.name = "se",
1075 	},
1076 	{
1077 		.name = "serial",
1078 		.compatible = "sab82532",
1079 	},
1080 	{},
1081 };
1082 MODULE_DEVICE_TABLE(of, sab_match);
1083 
1084 static struct platform_driver sab_driver = {
1085 	.driver = {
1086 		.name = "sab",
1087 		.owner = THIS_MODULE,
1088 		.of_match_table = sab_match,
1089 	},
1090 	.probe		= sab_probe,
1091 	.remove		= sab_remove,
1092 };
1093 
1094 static int __init sunsab_init(void)
1095 {
1096 	struct device_node *dp;
1097 	int err;
1098 	int num_channels = 0;
1099 
1100 	for_each_node_by_name(dp, "se")
1101 		num_channels += 2;
1102 	for_each_node_by_name(dp, "serial") {
1103 		if (of_device_is_compatible(dp, "sab82532"))
1104 			num_channels += 2;
1105 	}
1106 
1107 	if (num_channels) {
1108 		sunsab_ports = kzalloc(sizeof(struct uart_sunsab_port) *
1109 				       num_channels, GFP_KERNEL);
1110 		if (!sunsab_ports)
1111 			return -ENOMEM;
1112 
1113 		err = sunserial_register_minors(&sunsab_reg, num_channels);
1114 		if (err) {
1115 			kfree(sunsab_ports);
1116 			sunsab_ports = NULL;
1117 
1118 			return err;
1119 		}
1120 	}
1121 
1122 	return platform_driver_register(&sab_driver);
1123 }
1124 
1125 static void __exit sunsab_exit(void)
1126 {
1127 	platform_driver_unregister(&sab_driver);
1128 	if (sunsab_reg.nr) {
1129 		sunserial_unregister_minors(&sunsab_reg, sunsab_reg.nr);
1130 	}
1131 
1132 	kfree(sunsab_ports);
1133 	sunsab_ports = NULL;
1134 }
1135 
1136 module_init(sunsab_init);
1137 module_exit(sunsab_exit);
1138 
1139 MODULE_AUTHOR("Eddie C. Dost and David S. Miller");
1140 MODULE_DESCRIPTION("Sun SAB82532 serial port driver");
1141 MODULE_LICENSE("GPL");
1142