Merge ../to-linus-stable/
[linux-2.6] / drivers / serial / ip22zilog.c
1 /*
2  * Driver for Zilog serial chips found on SGI workstations and
3  * servers.  This driver could actually be made more generic.
4  *
5  * This is based on the drivers/serial/sunzilog.c code as of 2.6.0-test7 and the
6  * old drivers/sgi/char/sgiserial.c code which itself is based of the original
7  * drivers/sbus/char/zs.c code.  A lot of code has been simply moved over
8  * directly from there but much has been rewritten.  Credits therefore go out
9  * to David S. Miller, Eddie C. Dost, Pete Zaitcev, Ted Ts'o and Alex Buell
10  * for their work there.
11  *
12  *  Copyright (C) 2002 Ralf Baechle (ralf@linux-mips.org)
13  *  Copyright (C) 2002 David S. Miller (davem@redhat.com)
14  */
15 #include <linux/config.h>
16 #include <linux/module.h>
17 #include <linux/kernel.h>
18 #include <linux/sched.h>
19 #include <linux/errno.h>
20 #include <linux/delay.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/slab.h>
28 #include <linux/circ_buf.h>
29 #include <linux/serial.h>
30 #include <linux/sysrq.h>
31 #include <linux/console.h>
32 #include <linux/spinlock.h>
33 #include <linux/init.h>
34
35 #include <asm/io.h>
36 #include <asm/irq.h>
37 #include <asm/sgialib.h>
38 #include <asm/sgi/ioc.h>
39 #include <asm/sgi/hpc3.h>
40 #include <asm/sgi/ip22.h>
41
42 #if defined(CONFIG_SERIAL_IP22_ZILOG_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
43 #define SUPPORT_SYSRQ
44 #endif
45
46 #include <linux/serial_core.h>
47
48 #include "ip22zilog.h"
49
50 void ip22_do_break(void);
51
52 /*
53  * On IP22 we need to delay after register accesses but we do not need to
54  * flush writes.
55  */
56 #define ZSDELAY()               udelay(5)
57 #define ZSDELAY_LONG()          udelay(20)
58 #define ZS_WSYNC(channel)       do { } while (0)
59
60 #define NUM_IP22ZILOG           1
61 #define NUM_CHANNELS            (NUM_IP22ZILOG * 2)
62
63 #define ZS_CLOCK                3672000 /* Zilog input clock rate. */
64 #define ZS_CLOCK_DIVISOR        16      /* Divisor this driver uses. */
65
66 /*
67  * We wrap our port structure around the generic uart_port.
68  */
69 struct uart_ip22zilog_port {
70         struct uart_port                port;
71
72         /* IRQ servicing chain.  */
73         struct uart_ip22zilog_port      *next;
74
75         /* Current values of Zilog write registers.  */
76         unsigned char                   curregs[NUM_ZSREGS];
77
78         unsigned int                    flags;
79 #define IP22ZILOG_FLAG_IS_CONS          0x00000004
80 #define IP22ZILOG_FLAG_IS_KGDB          0x00000008
81 #define IP22ZILOG_FLAG_MODEM_STATUS     0x00000010
82 #define IP22ZILOG_FLAG_IS_CHANNEL_A     0x00000020
83 #define IP22ZILOG_FLAG_REGS_HELD        0x00000040
84 #define IP22ZILOG_FLAG_TX_STOPPED       0x00000080
85 #define IP22ZILOG_FLAG_TX_ACTIVE        0x00000100
86
87         unsigned int                    cflag;
88
89         /* L1-A keyboard break state.  */
90         int                             kbd_id;
91         int                             l1_down;
92
93         unsigned char                   parity_mask;
94         unsigned char                   prev_status;
95 };
96
97 #define ZILOG_CHANNEL_FROM_PORT(PORT)   ((struct zilog_channel *)((PORT)->membase))
98 #define UART_ZILOG(PORT)                ((struct uart_ip22zilog_port *)(PORT))
99 #define IP22ZILOG_GET_CURR_REG(PORT, REGNUM)            \
100         (UART_ZILOG(PORT)->curregs[REGNUM])
101 #define IP22ZILOG_SET_CURR_REG(PORT, REGNUM, REGVAL)    \
102         ((UART_ZILOG(PORT)->curregs[REGNUM]) = (REGVAL))
103 #define ZS_IS_CONS(UP)  ((UP)->flags & IP22ZILOG_FLAG_IS_CONS)
104 #define ZS_IS_KGDB(UP)  ((UP)->flags & IP22ZILOG_FLAG_IS_KGDB)
105 #define ZS_WANTS_MODEM_STATUS(UP)       ((UP)->flags & IP22ZILOG_FLAG_MODEM_STATUS)
106 #define ZS_IS_CHANNEL_A(UP)     ((UP)->flags & IP22ZILOG_FLAG_IS_CHANNEL_A)
107 #define ZS_REGS_HELD(UP)        ((UP)->flags & IP22ZILOG_FLAG_REGS_HELD)
108 #define ZS_TX_STOPPED(UP)       ((UP)->flags & IP22ZILOG_FLAG_TX_STOPPED)
109 #define ZS_TX_ACTIVE(UP)        ((UP)->flags & IP22ZILOG_FLAG_TX_ACTIVE)
110
111 /* Reading and writing Zilog8530 registers.  The delays are to make this
112  * driver work on the IP22 which needs a settling delay after each chip
113  * register access, other machines handle this in hardware via auxiliary
114  * flip-flops which implement the settle time we do in software.
115  *
116  * The port lock must be held and local IRQs must be disabled
117  * when {read,write}_zsreg is invoked.
118  */
119 static unsigned char read_zsreg(struct zilog_channel *channel,
120                                 unsigned char reg)
121 {
122         unsigned char retval;
123
124         writeb(reg, &channel->control);
125         ZSDELAY();
126         retval = readb(&channel->control);
127         ZSDELAY();
128
129         return retval;
130 }
131
132 static void write_zsreg(struct zilog_channel *channel,
133                         unsigned char reg, unsigned char value)
134 {
135         writeb(reg, &channel->control);
136         ZSDELAY();
137         writeb(value, &channel->control);
138         ZSDELAY();
139 }
140
141 static void ip22zilog_clear_fifo(struct zilog_channel *channel)
142 {
143         int i;
144
145         for (i = 0; i < 32; i++) {
146                 unsigned char regval;
147
148                 regval = readb(&channel->control);
149                 ZSDELAY();
150                 if (regval & Rx_CH_AV)
151                         break;
152
153                 regval = read_zsreg(channel, R1);
154                 readb(&channel->data);
155                 ZSDELAY();
156
157                 if (regval & (PAR_ERR | Rx_OVR | CRC_ERR)) {
158                         writeb(ERR_RES, &channel->control);
159                         ZSDELAY();
160                         ZS_WSYNC(channel);
161                 }
162         }
163 }
164
165 /* This function must only be called when the TX is not busy.  The UART
166  * port lock must be held and local interrupts disabled.
167  */
168 static void __load_zsregs(struct zilog_channel *channel, unsigned char *regs)
169 {
170         int i;
171
172         /* Let pending transmits finish.  */
173         for (i = 0; i < 1000; i++) {
174                 unsigned char stat = read_zsreg(channel, R1);
175                 if (stat & ALL_SNT)
176                         break;
177                 udelay(100);
178         }
179
180         writeb(ERR_RES, &channel->control);
181         ZSDELAY();
182         ZS_WSYNC(channel);
183
184         ip22zilog_clear_fifo(channel);
185
186         /* Disable all interrupts.  */
187         write_zsreg(channel, R1,
188                     regs[R1] & ~(RxINT_MASK | TxINT_ENAB | EXT_INT_ENAB));
189
190         /* Set parity, sync config, stop bits, and clock divisor.  */
191         write_zsreg(channel, R4, regs[R4]);
192
193         /* Set misc. TX/RX control bits.  */
194         write_zsreg(channel, R10, regs[R10]);
195
196         /* Set TX/RX controls sans the enable bits.  */
197         write_zsreg(channel, R3, regs[R3] & ~RxENAB);
198         write_zsreg(channel, R5, regs[R5] & ~TxENAB);
199
200         /* Synchronous mode config.  */
201         write_zsreg(channel, R6, regs[R6]);
202         write_zsreg(channel, R7, regs[R7]);
203
204         /* Don't mess with the interrupt vector (R2, unused by us) and
205          * master interrupt control (R9).  We make sure this is setup
206          * properly at probe time then never touch it again.
207          */
208
209         /* Disable baud generator.  */
210         write_zsreg(channel, R14, regs[R14] & ~BRENAB);
211
212         /* Clock mode control.  */
213         write_zsreg(channel, R11, regs[R11]);
214
215         /* Lower and upper byte of baud rate generator divisor.  */
216         write_zsreg(channel, R12, regs[R12]);
217         write_zsreg(channel, R13, regs[R13]);
218         
219         /* Now rewrite R14, with BRENAB (if set).  */
220         write_zsreg(channel, R14, regs[R14]);
221
222         /* External status interrupt control.  */
223         write_zsreg(channel, R15, regs[R15]);
224
225         /* Reset external status interrupts.  */
226         write_zsreg(channel, R0, RES_EXT_INT);
227         write_zsreg(channel, R0, RES_EXT_INT);
228
229         /* Rewrite R3/R5, this time without enables masked.  */
230         write_zsreg(channel, R3, regs[R3]);
231         write_zsreg(channel, R5, regs[R5]);
232
233         /* Rewrite R1, this time without IRQ enabled masked.  */
234         write_zsreg(channel, R1, regs[R1]);
235 }
236
237 /* Reprogram the Zilog channel HW registers with the copies found in the
238  * software state struct.  If the transmitter is busy, we defer this update
239  * until the next TX complete interrupt.  Else, we do it right now.
240  *
241  * The UART port lock must be held and local interrupts disabled.
242  */
243 static void ip22zilog_maybe_update_regs(struct uart_ip22zilog_port *up,
244                                        struct zilog_channel *channel)
245 {
246         if (!ZS_REGS_HELD(up)) {
247                 if (ZS_TX_ACTIVE(up)) {
248                         up->flags |= IP22ZILOG_FLAG_REGS_HELD;
249                 } else {
250                         __load_zsregs(channel, up->curregs);
251                 }
252         }
253 }
254
255 static void ip22zilog_receive_chars(struct uart_ip22zilog_port *up,
256                                    struct zilog_channel *channel,
257                                    struct pt_regs *regs)
258 {
259         struct tty_struct *tty = up->port.info->tty;    /* XXX info==NULL? */
260
261         while (1) {
262                 unsigned char ch, r1;
263
264                 if (unlikely(tty->flip.count >= TTY_FLIPBUF_SIZE)) {
265                         tty->flip.work.func((void *)tty);
266                         if (tty->flip.count >= TTY_FLIPBUF_SIZE)
267                                 return;         /* XXX Ignores SysRq when we need it most. Fix. */
268                 }
269
270                 r1 = read_zsreg(channel, R1);
271                 if (r1 & (PAR_ERR | Rx_OVR | CRC_ERR)) {
272                         writeb(ERR_RES, &channel->control);
273                         ZSDELAY();
274                         ZS_WSYNC(channel);
275                 }
276
277                 ch = readb(&channel->control);
278                 ZSDELAY();
279
280                 /* This funny hack depends upon BRK_ABRT not interfering
281                  * with the other bits we care about in R1.
282                  */
283                 if (ch & BRK_ABRT)
284                         r1 |= BRK_ABRT;
285
286                 ch = readb(&channel->data);
287                 ZSDELAY();
288
289                 ch &= up->parity_mask;
290
291                 if (ZS_IS_CONS(up) && (r1 & BRK_ABRT)) {
292                         /* Wait for BREAK to deassert to avoid potentially
293                          * confusing the PROM.
294                          */
295                         while (1) {
296                                 ch = readb(&channel->control);
297                                 ZSDELAY();
298                                 if (!(ch & BRK_ABRT))
299                                         break;
300                         }
301                         ip22_do_break();
302                         return;
303                 }
304
305                 /* A real serial line, record the character and status.  */
306                 *tty->flip.char_buf_ptr = ch;
307                 *tty->flip.flag_buf_ptr = TTY_NORMAL;
308                 up->port.icount.rx++;
309                 if (r1 & (BRK_ABRT | PAR_ERR | Rx_OVR | CRC_ERR)) {
310                         if (r1 & BRK_ABRT) {
311                                 r1 &= ~(PAR_ERR | CRC_ERR);
312                                 up->port.icount.brk++;
313                                 if (uart_handle_break(&up->port))
314                                         goto next_char;
315                         }
316                         else if (r1 & PAR_ERR)
317                                 up->port.icount.parity++;
318                         else if (r1 & CRC_ERR)
319                                 up->port.icount.frame++;
320                         if (r1 & Rx_OVR)
321                                 up->port.icount.overrun++;
322                         r1 &= up->port.read_status_mask;
323                         if (r1 & BRK_ABRT)
324                                 *tty->flip.flag_buf_ptr = TTY_BREAK;
325                         else if (r1 & PAR_ERR)
326                                 *tty->flip.flag_buf_ptr = TTY_PARITY;
327                         else if (r1 & CRC_ERR)
328                                 *tty->flip.flag_buf_ptr = TTY_FRAME;
329                 }
330                 if (uart_handle_sysrq_char(&up->port, ch, regs))
331                         goto next_char;
332
333                 if (up->port.ignore_status_mask == 0xff ||
334                     (r1 & up->port.ignore_status_mask) == 0) {
335                         tty->flip.flag_buf_ptr++;
336                         tty->flip.char_buf_ptr++;
337                         tty->flip.count++;
338                 }
339                 if ((r1 & Rx_OVR) &&
340                     tty->flip.count < TTY_FLIPBUF_SIZE) {
341                         *tty->flip.flag_buf_ptr = TTY_OVERRUN;
342                         tty->flip.flag_buf_ptr++;
343                         tty->flip.char_buf_ptr++;
344                         tty->flip.count++;
345                 }
346         next_char:
347                 ch = readb(&channel->control);
348                 ZSDELAY();
349                 if (!(ch & Rx_CH_AV))
350                         break;
351         }
352
353         tty_flip_buffer_push(tty);
354 }
355
356 static void ip22zilog_status_handle(struct uart_ip22zilog_port *up,
357                                    struct zilog_channel *channel,
358                                    struct pt_regs *regs)
359 {
360         unsigned char status;
361
362         status = readb(&channel->control);
363         ZSDELAY();
364
365         writeb(RES_EXT_INT, &channel->control);
366         ZSDELAY();
367         ZS_WSYNC(channel);
368
369         if (ZS_WANTS_MODEM_STATUS(up)) {
370                 if (status & SYNC)
371                         up->port.icount.dsr++;
372
373                 /* The Zilog just gives us an interrupt when DCD/CTS/etc. change.
374                  * But it does not tell us which bit has changed, we have to keep
375                  * track of this ourselves.
376                  */
377                 if ((status & DCD) ^ up->prev_status)
378                         uart_handle_dcd_change(&up->port,
379                                                (status & DCD));
380                 if ((status & CTS) ^ up->prev_status)
381                         uart_handle_cts_change(&up->port,
382                                                (status & CTS));
383
384                 wake_up_interruptible(&up->port.info->delta_msr_wait);
385         }
386
387         up->prev_status = status;
388 }
389
390 static void ip22zilog_transmit_chars(struct uart_ip22zilog_port *up,
391                                     struct zilog_channel *channel)
392 {
393         struct circ_buf *xmit;
394
395         if (ZS_IS_CONS(up)) {
396                 unsigned char status = readb(&channel->control);
397                 ZSDELAY();
398
399                 /* TX still busy?  Just wait for the next TX done interrupt.
400                  *
401                  * It can occur because of how we do serial console writes.  It would
402                  * be nice to transmit console writes just like we normally would for
403                  * a TTY line. (ie. buffered and TX interrupt driven).  That is not
404                  * easy because console writes cannot sleep.  One solution might be
405                  * to poll on enough port->xmit space becomming free.  -DaveM
406                  */
407                 if (!(status & Tx_BUF_EMP))
408                         return;
409         }
410
411         up->flags &= ~IP22ZILOG_FLAG_TX_ACTIVE;
412
413         if (ZS_REGS_HELD(up)) {
414                 __load_zsregs(channel, up->curregs);
415                 up->flags &= ~IP22ZILOG_FLAG_REGS_HELD;
416         }
417
418         if (ZS_TX_STOPPED(up)) {
419                 up->flags &= ~IP22ZILOG_FLAG_TX_STOPPED;
420                 goto ack_tx_int;
421         }
422
423         if (up->port.x_char) {
424                 up->flags |= IP22ZILOG_FLAG_TX_ACTIVE;
425                 writeb(up->port.x_char, &channel->data);
426                 ZSDELAY();
427                 ZS_WSYNC(channel);
428
429                 up->port.icount.tx++;
430                 up->port.x_char = 0;
431                 return;
432         }
433
434         if (up->port.info == NULL)
435                 goto ack_tx_int;
436         xmit = &up->port.info->xmit;
437         if (uart_circ_empty(xmit)) {
438                 uart_write_wakeup(&up->port);
439                 goto ack_tx_int;
440         }
441         if (uart_tx_stopped(&up->port))
442                 goto ack_tx_int;
443
444         up->flags |= IP22ZILOG_FLAG_TX_ACTIVE;
445         writeb(xmit->buf[xmit->tail], &channel->data);
446         ZSDELAY();
447         ZS_WSYNC(channel);
448
449         xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
450         up->port.icount.tx++;
451
452         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
453                 uart_write_wakeup(&up->port);
454
455         return;
456
457 ack_tx_int:
458         writeb(RES_Tx_P, &channel->control);
459         ZSDELAY();
460         ZS_WSYNC(channel);
461 }
462
463 static irqreturn_t ip22zilog_interrupt(int irq, void *dev_id, struct pt_regs *regs)
464 {
465         struct uart_ip22zilog_port *up = dev_id;
466
467         while (up) {
468                 struct zilog_channel *channel
469                         = ZILOG_CHANNEL_FROM_PORT(&up->port);
470                 unsigned char r3;
471
472                 spin_lock(&up->port.lock);
473                 r3 = read_zsreg(channel, R3);
474
475                 /* Channel A */
476                 if (r3 & (CHAEXT | CHATxIP | CHARxIP)) {
477                         writeb(RES_H_IUS, &channel->control);
478                         ZSDELAY();
479                         ZS_WSYNC(channel);
480
481                         if (r3 & CHARxIP)
482                                 ip22zilog_receive_chars(up, channel, regs);
483                         if (r3 & CHAEXT)
484                                 ip22zilog_status_handle(up, channel, regs);
485                         if (r3 & CHATxIP)
486                                 ip22zilog_transmit_chars(up, channel);
487                 }
488                 spin_unlock(&up->port.lock);
489
490                 /* Channel B */
491                 up = up->next;
492                 channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
493
494                 spin_lock(&up->port.lock);
495                 if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) {
496                         writeb(RES_H_IUS, &channel->control);
497                         ZSDELAY();
498                         ZS_WSYNC(channel);
499
500                         if (r3 & CHBRxIP)
501                                 ip22zilog_receive_chars(up, channel, regs);
502                         if (r3 & CHBEXT)
503                                 ip22zilog_status_handle(up, channel, regs);
504                         if (r3 & CHBTxIP)
505                                 ip22zilog_transmit_chars(up, channel);
506                 }
507                 spin_unlock(&up->port.lock);
508
509                 up = up->next;
510         }
511
512         return IRQ_HANDLED;
513 }
514
515 /* A convenient way to quickly get R0 status.  The caller must _not_ hold the
516  * port lock, it is acquired here.
517  */
518 static __inline__ unsigned char ip22zilog_read_channel_status(struct uart_port *port)
519 {
520         struct zilog_channel *channel;
521         unsigned char status;
522
523         channel = ZILOG_CHANNEL_FROM_PORT(port);
524         status = readb(&channel->control);
525         ZSDELAY();
526
527         return status;
528 }
529
530 /* The port lock is not held.  */
531 static unsigned int ip22zilog_tx_empty(struct uart_port *port)
532 {
533         unsigned long flags;
534         unsigned char status;
535         unsigned int ret;
536
537         spin_lock_irqsave(&port->lock, flags);
538
539         status = ip22zilog_read_channel_status(port);
540
541         spin_unlock_irqrestore(&port->lock, flags);
542
543         if (status & Tx_BUF_EMP)
544                 ret = TIOCSER_TEMT;
545         else
546                 ret = 0;
547
548         return ret;
549 }
550
551 /* The port lock is held and interrupts are disabled.  */
552 static unsigned int ip22zilog_get_mctrl(struct uart_port *port)
553 {
554         unsigned char status;
555         unsigned int ret;
556
557         status = ip22zilog_read_channel_status(port);
558
559         ret = 0;
560         if (status & DCD)
561                 ret |= TIOCM_CAR;
562         if (status & SYNC)
563                 ret |= TIOCM_DSR;
564         if (status & CTS)
565                 ret |= TIOCM_CTS;
566
567         return ret;
568 }
569
570 /* The port lock is held and interrupts are disabled.  */
571 static void ip22zilog_set_mctrl(struct uart_port *port, unsigned int mctrl)
572 {
573         struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
574         struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(port);
575         unsigned char set_bits, clear_bits;
576
577         set_bits = clear_bits = 0;
578
579         if (mctrl & TIOCM_RTS)
580                 set_bits |= RTS;
581         else
582                 clear_bits |= RTS;
583         if (mctrl & TIOCM_DTR)
584                 set_bits |= DTR;
585         else
586                 clear_bits |= DTR;
587
588         /* NOTE: Not subject to 'transmitter active' rule.  */ 
589         up->curregs[R5] |= set_bits;
590         up->curregs[R5] &= ~clear_bits;
591         write_zsreg(channel, R5, up->curregs[R5]);
592 }
593
594 /* The port lock is held and interrupts are disabled.  */
595 static void ip22zilog_stop_tx(struct uart_port *port, unsigned int tty_stop)
596 {
597         struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
598
599         up->flags |= IP22ZILOG_FLAG_TX_STOPPED;
600 }
601
602 /* The port lock is held and interrupts are disabled.  */
603 static void ip22zilog_start_tx(struct uart_port *port, unsigned int tty_start)
604 {
605         struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
606         struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(port);
607         unsigned char status;
608
609         up->flags |= IP22ZILOG_FLAG_TX_ACTIVE;
610         up->flags &= ~IP22ZILOG_FLAG_TX_STOPPED;
611
612         status = readb(&channel->control);
613         ZSDELAY();
614
615         /* TX busy?  Just wait for the TX done interrupt.  */
616         if (!(status & Tx_BUF_EMP))
617                 return;
618
619         /* Send the first character to jump-start the TX done
620          * IRQ sending engine.
621          */
622         if (port->x_char) {
623                 writeb(port->x_char, &channel->data);
624                 ZSDELAY();
625                 ZS_WSYNC(channel);
626
627                 port->icount.tx++;
628                 port->x_char = 0;
629         } else {
630                 struct circ_buf *xmit = &port->info->xmit;
631
632                 writeb(xmit->buf[xmit->tail], &channel->data);
633                 ZSDELAY();
634                 ZS_WSYNC(channel);
635
636                 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
637                 port->icount.tx++;
638
639                 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
640                         uart_write_wakeup(&up->port);
641         }
642 }
643
644 /* The port lock is held and interrupts are disabled.  */
645 static void ip22zilog_stop_rx(struct uart_port *port)
646 {
647         struct uart_ip22zilog_port *up = UART_ZILOG(port);
648         struct zilog_channel *channel;
649
650         if (ZS_IS_CONS(up))
651                 return;
652
653         channel = ZILOG_CHANNEL_FROM_PORT(port);
654
655         /* Disable all RX interrupts.  */
656         up->curregs[R1] &= ~RxINT_MASK;
657         ip22zilog_maybe_update_regs(up, channel);
658 }
659
660 /* The port lock is held.  */
661 static void ip22zilog_enable_ms(struct uart_port *port)
662 {
663         struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
664         struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(port);
665         unsigned char new_reg;
666
667         new_reg = up->curregs[R15] | (DCDIE | SYNCIE | CTSIE);
668         if (new_reg != up->curregs[R15]) {
669                 up->curregs[R15] = new_reg;
670
671                 /* NOTE: Not subject to 'transmitter active' rule.  */ 
672                 write_zsreg(channel, R15, up->curregs[R15]);
673         }
674 }
675
676 /* The port lock is not held.  */
677 static void ip22zilog_break_ctl(struct uart_port *port, int break_state)
678 {
679         struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
680         struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(port);
681         unsigned char set_bits, clear_bits, new_reg;
682         unsigned long flags;
683
684         set_bits = clear_bits = 0;
685
686         if (break_state)
687                 set_bits |= SND_BRK;
688         else
689                 clear_bits |= SND_BRK;
690
691         spin_lock_irqsave(&port->lock, flags);
692
693         new_reg = (up->curregs[R5] | set_bits) & ~clear_bits;
694         if (new_reg != up->curregs[R5]) {
695                 up->curregs[R5] = new_reg;
696
697                 /* NOTE: Not subject to 'transmitter active' rule.  */ 
698                 write_zsreg(channel, R5, up->curregs[R5]);
699         }
700
701         spin_unlock_irqrestore(&port->lock, flags);
702 }
703
704 static void __ip22zilog_startup(struct uart_ip22zilog_port *up)
705 {
706         struct zilog_channel *channel;
707
708         channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
709         up->prev_status = readb(&channel->control);
710
711         /* Enable receiver and transmitter.  */
712         up->curregs[R3] |= RxENAB;
713         up->curregs[R5] |= TxENAB;
714
715         up->curregs[R1] |= EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB;
716         ip22zilog_maybe_update_regs(up, channel);
717 }
718
719 static int ip22zilog_startup(struct uart_port *port)
720 {
721         struct uart_ip22zilog_port *up = UART_ZILOG(port);
722         unsigned long flags;
723
724         if (ZS_IS_CONS(up))
725                 return 0;
726
727         spin_lock_irqsave(&port->lock, flags);
728         __ip22zilog_startup(up);
729         spin_unlock_irqrestore(&port->lock, flags);
730         return 0;
731 }
732
733 /*
734  * The test for ZS_IS_CONS is explained by the following e-mail:
735  *****
736  * From: Russell King <rmk@arm.linux.org.uk>
737  * Date: Sun, 8 Dec 2002 10:18:38 +0000
738  *
739  * On Sun, Dec 08, 2002 at 02:43:36AM -0500, Pete Zaitcev wrote:
740  * > I boot my 2.5 boxes using "console=ttyS0,9600" argument,
741  * > and I noticed that something is not right with reference
742  * > counting in this case. It seems that when the console
743  * > is open by kernel initially, this is not accounted
744  * > as an open, and uart_startup is not called.
745  *
746  * That is correct.  We are unable to call uart_startup when the serial
747  * console is initialised because it may need to allocate memory (as
748  * request_irq does) and the memory allocators may not have been
749  * initialised.
750  *
751  * 1. initialise the port into a state where it can send characters in the
752  *    console write method.
753  *
754  * 2. don't do the actual hardware shutdown in your shutdown() method (but
755  *    do the normal software shutdown - ie, free irqs etc)
756  *****
757  */
758 static void ip22zilog_shutdown(struct uart_port *port)
759 {
760         struct uart_ip22zilog_port *up = UART_ZILOG(port);
761         struct zilog_channel *channel;
762         unsigned long flags;
763
764         if (ZS_IS_CONS(up))
765                 return;
766
767         spin_lock_irqsave(&port->lock, flags);
768
769         channel = ZILOG_CHANNEL_FROM_PORT(port);
770
771         /* Disable receiver and transmitter.  */
772         up->curregs[R3] &= ~RxENAB;
773         up->curregs[R5] &= ~TxENAB;
774
775         /* Disable all interrupts and BRK assertion.  */
776         up->curregs[R1] &= ~(EXT_INT_ENAB | TxINT_ENAB | RxINT_MASK);
777         up->curregs[R5] &= ~SND_BRK;
778         ip22zilog_maybe_update_regs(up, channel);
779
780         spin_unlock_irqrestore(&port->lock, flags);
781 }
782
783 /* Shared by TTY driver and serial console setup.  The port lock is held
784  * and local interrupts are disabled.
785  */
786 static void
787 ip22zilog_convert_to_zs(struct uart_ip22zilog_port *up, unsigned int cflag,
788                        unsigned int iflag, int brg)
789 {
790
791         up->curregs[R10] = NRZ;
792         up->curregs[R11] = TCBR | RCBR;
793
794         /* Program BAUD and clock source. */
795         up->curregs[R4] &= ~XCLK_MASK;
796         up->curregs[R4] |= X16CLK;
797         up->curregs[R12] = brg & 0xff;
798         up->curregs[R13] = (brg >> 8) & 0xff;
799         up->curregs[R14] = BRENAB;
800
801         /* Character size, stop bits, and parity. */
802         up->curregs[3] &= ~RxN_MASK;
803         up->curregs[5] &= ~TxN_MASK;
804         switch (cflag & CSIZE) {
805         case CS5:
806                 up->curregs[3] |= Rx5;
807                 up->curregs[5] |= Tx5;
808                 up->parity_mask = 0x1f;
809                 break;
810         case CS6:
811                 up->curregs[3] |= Rx6;
812                 up->curregs[5] |= Tx6;
813                 up->parity_mask = 0x3f;
814                 break;
815         case CS7:
816                 up->curregs[3] |= Rx7;
817                 up->curregs[5] |= Tx7;
818                 up->parity_mask = 0x7f;
819                 break;
820         case CS8:
821         default:
822                 up->curregs[3] |= Rx8;
823                 up->curregs[5] |= Tx8;
824                 up->parity_mask = 0xff;
825                 break;
826         };
827         up->curregs[4] &= ~0x0c;
828         if (cflag & CSTOPB)
829                 up->curregs[4] |= SB2;
830         else
831                 up->curregs[4] |= SB1;
832         if (cflag & PARENB)
833                 up->curregs[4] |= PAR_ENAB;
834         else
835                 up->curregs[4] &= ~PAR_ENAB;
836         if (!(cflag & PARODD))
837                 up->curregs[4] |= PAR_EVEN;
838         else
839                 up->curregs[4] &= ~PAR_EVEN;
840
841         up->port.read_status_mask = Rx_OVR;
842         if (iflag & INPCK)
843                 up->port.read_status_mask |= CRC_ERR | PAR_ERR;
844         if (iflag & (BRKINT | PARMRK))
845                 up->port.read_status_mask |= BRK_ABRT;
846
847         up->port.ignore_status_mask = 0;
848         if (iflag & IGNPAR)
849                 up->port.ignore_status_mask |= CRC_ERR | PAR_ERR;
850         if (iflag & IGNBRK) {
851                 up->port.ignore_status_mask |= BRK_ABRT;
852                 if (iflag & IGNPAR)
853                         up->port.ignore_status_mask |= Rx_OVR;
854         }
855
856         if ((cflag & CREAD) == 0)
857                 up->port.ignore_status_mask = 0xff;
858 }
859
860 /* The port lock is not held.  */
861 static void
862 ip22zilog_set_termios(struct uart_port *port, struct termios *termios,
863                       struct termios *old)
864 {
865         struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
866         unsigned long flags;
867         int baud, brg;
868
869         baud = uart_get_baud_rate(port, termios, old, 1200, 76800);
870
871         spin_lock_irqsave(&up->port.lock, flags);
872
873         brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);
874
875         ip22zilog_convert_to_zs(up, termios->c_cflag, termios->c_iflag, brg);
876
877         if (UART_ENABLE_MS(&up->port, termios->c_cflag))
878                 up->flags |= IP22ZILOG_FLAG_MODEM_STATUS;
879         else
880                 up->flags &= ~IP22ZILOG_FLAG_MODEM_STATUS;
881
882         up->cflag = termios->c_cflag;
883
884         ip22zilog_maybe_update_regs(up, ZILOG_CHANNEL_FROM_PORT(port));
885
886         spin_unlock_irqrestore(&up->port.lock, flags);
887 }
888
889 static const char *ip22zilog_type(struct uart_port *port)
890 {
891         return "IP22-Zilog";
892 }
893
894 /* We do not request/release mappings of the registers here, this
895  * happens at early serial probe time.
896  */
897 static void ip22zilog_release_port(struct uart_port *port)
898 {
899 }
900
901 static int ip22zilog_request_port(struct uart_port *port)
902 {
903         return 0;
904 }
905
906 /* These do not need to do anything interesting either.  */
907 static void ip22zilog_config_port(struct uart_port *port, int flags)
908 {
909 }
910
911 /* We do not support letting the user mess with the divisor, IRQ, etc. */
912 static int ip22zilog_verify_port(struct uart_port *port, struct serial_struct *ser)
913 {
914         return -EINVAL;
915 }
916
917 static struct uart_ops ip22zilog_pops = {
918         .tx_empty       =       ip22zilog_tx_empty,
919         .set_mctrl      =       ip22zilog_set_mctrl,
920         .get_mctrl      =       ip22zilog_get_mctrl,
921         .stop_tx        =       ip22zilog_stop_tx,
922         .start_tx       =       ip22zilog_start_tx,
923         .stop_rx        =       ip22zilog_stop_rx,
924         .enable_ms      =       ip22zilog_enable_ms,
925         .break_ctl      =       ip22zilog_break_ctl,
926         .startup        =       ip22zilog_startup,
927         .shutdown       =       ip22zilog_shutdown,
928         .set_termios    =       ip22zilog_set_termios,
929         .type           =       ip22zilog_type,
930         .release_port   =       ip22zilog_release_port,
931         .request_port   =       ip22zilog_request_port,
932         .config_port    =       ip22zilog_config_port,
933         .verify_port    =       ip22zilog_verify_port,
934 };
935
936 static struct uart_ip22zilog_port *ip22zilog_port_table;
937 static struct zilog_layout **ip22zilog_chip_regs;
938
939 static struct uart_ip22zilog_port *ip22zilog_irq_chain;
940 static int zilog_irq = -1;
941
942 static void * __init alloc_one_table(unsigned long size)
943 {
944         void *ret;
945
946         ret = kmalloc(size, GFP_KERNEL);
947         if (ret != NULL)
948                 memset(ret, 0, size);
949
950         return ret;
951 }
952
953 static void __init ip22zilog_alloc_tables(void)
954 {
955         ip22zilog_port_table = (struct uart_ip22zilog_port *)
956                 alloc_one_table(NUM_CHANNELS * sizeof(struct uart_ip22zilog_port));
957         ip22zilog_chip_regs = (struct zilog_layout **)
958                 alloc_one_table(NUM_IP22ZILOG * sizeof(struct zilog_layout *));
959
960         if (ip22zilog_port_table == NULL || ip22zilog_chip_regs == NULL) {
961                 panic("IP22-Zilog: Cannot allocate IP22-Zilog tables.");
962         }
963 }
964
965 /* Get the address of the registers for IP22-Zilog instance CHIP.  */
966 static struct zilog_layout * __init get_zs(int chip)
967 {
968         unsigned long base;
969
970         if (chip < 0 || chip >= NUM_IP22ZILOG) {
971                 panic("IP22-Zilog: Illegal chip number %d in get_zs.", chip);
972         }
973
974         /* Not probe-able, hard code it. */
975         base = (unsigned long) &sgioc->uart;
976
977         zilog_irq = SGI_SERIAL_IRQ;
978         request_mem_region(base, 8, "IP22-Zilog");
979
980         return (struct zilog_layout *) base;
981 }
982
983 #define ZS_PUT_CHAR_MAX_DELAY   2000    /* 10 ms */
984
985 #ifdef CONFIG_SERIAL_IP22_ZILOG_CONSOLE
986 static void ip22zilog_put_char(struct zilog_channel *channel, unsigned char ch)
987 {
988         int loops = ZS_PUT_CHAR_MAX_DELAY;
989
990         /* This is a timed polling loop so do not switch the explicit
991          * udelay with ZSDELAY as that is a NOP on some platforms.  -DaveM
992          */
993         do {
994                 unsigned char val = readb(&channel->control);
995                 if (val & Tx_BUF_EMP) {
996                         ZSDELAY();
997                         break;
998                 }
999                 udelay(5);
1000         } while (--loops);
1001
1002         writeb(ch, &channel->data);
1003         ZSDELAY();
1004         ZS_WSYNC(channel);
1005 }
1006
1007 static void
1008 ip22zilog_console_write(struct console *con, const char *s, unsigned int count)
1009 {
1010         struct uart_ip22zilog_port *up = &ip22zilog_port_table[con->index];
1011         struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
1012         unsigned long flags;
1013         int i;
1014
1015         spin_lock_irqsave(&up->port.lock, flags);
1016         for (i = 0; i < count; i++, s++) {
1017                 ip22zilog_put_char(channel, *s);
1018                 if (*s == 10)
1019                         ip22zilog_put_char(channel, 13);
1020         }
1021         udelay(2);
1022         spin_unlock_irqrestore(&up->port.lock, flags);
1023 }
1024
1025 void
1026 ip22serial_console_termios(struct console *con, char *options)
1027 {
1028         int baud = 9600, bits = 8, cflag;
1029         int parity = 'n';
1030         int flow = 'n';
1031
1032         if (options)
1033                 uart_parse_options(options, &baud, &parity, &bits, &flow);
1034
1035         cflag = CREAD | HUPCL | CLOCAL;
1036
1037         switch (baud) {
1038                 case 150: cflag |= B150; break;
1039                 case 300: cflag |= B300; break;
1040                 case 600: cflag |= B600; break;
1041                 case 1200: cflag |= B1200; break;
1042                 case 2400: cflag |= B2400; break;
1043                 case 4800: cflag |= B4800; break;
1044                 case 9600: cflag |= B9600; break;
1045                 case 19200: cflag |= B19200; break;
1046                 case 38400: cflag |= B38400; break;
1047                 default: baud = 9600; cflag |= B9600; break;
1048         }
1049
1050         con->cflag = cflag | CS8;                       /* 8N1 */
1051 }
1052
1053 static int __init ip22zilog_console_setup(struct console *con, char *options)
1054 {
1055         struct uart_ip22zilog_port *up = &ip22zilog_port_table[con->index];
1056         unsigned long flags;
1057         int baud, brg;
1058
1059         printk("Console: ttyS%d (IP22-Zilog)\n", con->index);
1060
1061         /* Get firmware console settings.  */
1062         ip22serial_console_termios(con, options);
1063
1064         /* Firmware console speed is limited to 150-->38400 baud so
1065          * this hackish cflag thing is OK.
1066          */
1067         switch (con->cflag & CBAUD) {
1068         case B150: baud = 150; break;
1069         case B300: baud = 300; break;
1070         case B600: baud = 600; break;
1071         case B1200: baud = 1200; break;
1072         case B2400: baud = 2400; break;
1073         case B4800: baud = 4800; break;
1074         default: case B9600: baud = 9600; break;
1075         case B19200: baud = 19200; break;
1076         case B38400: baud = 38400; break;
1077         };
1078
1079         brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);
1080
1081         spin_lock_irqsave(&up->port.lock, flags);
1082
1083         up->curregs[R15] = BRKIE;
1084         ip22zilog_convert_to_zs(up, con->cflag, 0, brg);
1085
1086         __ip22zilog_startup(up);
1087
1088         spin_unlock_irqrestore(&up->port.lock, flags);
1089
1090         return 0;
1091 }
1092
1093 static struct uart_driver ip22zilog_reg;
1094
1095 static struct console ip22zilog_console = {
1096         .name   =       "ttyS",
1097         .write  =       ip22zilog_console_write,
1098         .device =       uart_console_device,
1099         .setup  =       ip22zilog_console_setup,
1100         .flags  =       CON_PRINTBUFFER,
1101         .index  =       -1,
1102         .data   =       &ip22zilog_reg,
1103 };
1104 #endif /* CONFIG_SERIAL_IP22_ZILOG_CONSOLE */
1105
1106 static struct uart_driver ip22zilog_reg = {
1107         .owner          = THIS_MODULE,
1108         .driver_name    = "serial",
1109         .devfs_name     = "tts/",
1110         .dev_name       = "ttyS",
1111         .major          = TTY_MAJOR,
1112         .minor          = 64,
1113         .nr             = NUM_CHANNELS,
1114 #ifdef CONFIG_SERIAL_IP22_ZILOG_CONSOLE
1115         .cons           = &ip22zilog_console,
1116 #endif
1117 };
1118
1119 static void __init ip22zilog_prepare(void)
1120 {
1121         struct uart_ip22zilog_port *up;
1122         struct zilog_layout *rp;
1123         int channel, chip;
1124
1125         /*
1126          * Temporary fix.
1127          */
1128         for (channel = 0; channel < NUM_CHANNELS; channel++)
1129                 spin_lock_init(&ip22zilog_port_table[channel].port.lock);
1130
1131         ip22zilog_irq_chain = &ip22zilog_port_table[NUM_CHANNELS - 1];
1132         up = &ip22zilog_port_table[0];
1133         for (channel = NUM_CHANNELS - 1 ; channel > 0; channel--)
1134                 up[channel].next = &up[channel - 1];
1135         up[channel].next = NULL;
1136
1137         for (chip = 0; chip < NUM_IP22ZILOG; chip++) {
1138                 if (!ip22zilog_chip_regs[chip]) {
1139                         ip22zilog_chip_regs[chip] = rp = get_zs(chip);
1140
1141                         up[(chip * 2) + 0].port.membase = (char *) &rp->channelB;
1142                         up[(chip * 2) + 1].port.membase = (char *) &rp->channelA;
1143
1144                         /* In theory mapbase is the physical address ...  */
1145                         up[(chip * 2) + 0].port.mapbase =
1146                                 (unsigned long) ioremap((unsigned long) &rp->channelB, 8);
1147                         up[(chip * 2) + 1].port.mapbase =
1148                                 (unsigned long) ioremap((unsigned long) &rp->channelA, 8);
1149                 }
1150
1151                 /* Channel A */
1152                 up[(chip * 2) + 0].port.iotype = UPIO_MEM;
1153                 up[(chip * 2) + 0].port.irq = zilog_irq;
1154                 up[(chip * 2) + 0].port.uartclk = ZS_CLOCK;
1155                 up[(chip * 2) + 0].port.fifosize = 1;
1156                 up[(chip * 2) + 0].port.ops = &ip22zilog_pops;
1157                 up[(chip * 2) + 0].port.type = PORT_IP22ZILOG;
1158                 up[(chip * 2) + 0].port.flags = 0;
1159                 up[(chip * 2) + 0].port.line = (chip * 2) + 0;
1160                 up[(chip * 2) + 0].flags = 0;
1161
1162                 /* Channel B */
1163                 up[(chip * 2) + 1].port.iotype = UPIO_MEM;
1164                 up[(chip * 2) + 1].port.irq = zilog_irq;
1165                 up[(chip * 2) + 1].port.uartclk = ZS_CLOCK;
1166                 up[(chip * 2) + 1].port.fifosize = 1;
1167                 up[(chip * 2) + 1].port.ops = &ip22zilog_pops;
1168                 up[(chip * 2) + 1].port.type = PORT_IP22ZILOG;
1169                 up[(chip * 2) + 1].port.flags |= IP22ZILOG_FLAG_IS_CHANNEL_A;
1170                 up[(chip * 2) + 1].port.line = (chip * 2) + 1;
1171                 up[(chip * 2) + 1].flags = 0;
1172         }
1173 }
1174
1175 static void __init ip22zilog_init_hw(void)
1176 {
1177         int i;
1178
1179         for (i = 0; i < NUM_CHANNELS; i++) {
1180                 struct uart_ip22zilog_port *up = &ip22zilog_port_table[i];
1181                 struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
1182                 unsigned long flags;
1183                 int baud, brg;
1184
1185                 spin_lock_irqsave(&up->port.lock, flags);
1186
1187                 if (ZS_IS_CHANNEL_A(up)) {
1188                         write_zsreg(channel, R9, FHWRES);
1189                         ZSDELAY_LONG();
1190                         (void) read_zsreg(channel, R0);
1191                 }
1192
1193                 /* Normal serial TTY. */
1194                 up->parity_mask = 0xff;
1195                 up->curregs[R1] = EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB;
1196                 up->curregs[R4] = PAR_EVEN | X16CLK | SB1;
1197                 up->curregs[R3] = RxENAB | Rx8;
1198                 up->curregs[R5] = TxENAB | Tx8;
1199                 up->curregs[R9] = NV | MIE;
1200                 up->curregs[R10] = NRZ;
1201                 up->curregs[R11] = TCBR | RCBR;
1202                 baud = 9600;
1203                 brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);
1204                 up->curregs[R12] = (brg & 0xff);
1205                 up->curregs[R13] = (brg >> 8) & 0xff;
1206                 up->curregs[R14] = BRENAB;
1207                 __load_zsregs(channel, up->curregs);
1208                 /* set master interrupt enable */
1209                 write_zsreg(channel, R9, up->curregs[R9]);
1210
1211                 spin_unlock_irqrestore(&up->port.lock, flags);
1212         }
1213 }
1214
1215 static int __init ip22zilog_ports_init(void)
1216 {
1217         int ret;
1218
1219         printk(KERN_INFO "Serial: IP22 Zilog driver (%d chips).\n", NUM_IP22ZILOG);
1220
1221         ip22zilog_prepare();
1222
1223         if (request_irq(zilog_irq, ip22zilog_interrupt, 0,
1224                         "IP22-Zilog", ip22zilog_irq_chain)) {
1225                 panic("IP22-Zilog: Unable to register zs interrupt handler.\n");
1226         }
1227
1228         ip22zilog_init_hw();
1229
1230         ret = uart_register_driver(&ip22zilog_reg);
1231         if (ret == 0) {
1232                 int i;
1233
1234                 for (i = 0; i < NUM_CHANNELS; i++) {
1235                         struct uart_ip22zilog_port *up = &ip22zilog_port_table[i];
1236
1237                         uart_add_one_port(&ip22zilog_reg, &up->port);
1238                 }
1239         }
1240
1241         return ret;
1242 }
1243
1244 static int __init ip22zilog_init(void)
1245 {
1246         /* IP22 Zilog setup is hard coded, no probing to do.  */
1247         ip22zilog_alloc_tables();
1248         ip22zilog_ports_init();
1249
1250         return 0;
1251 }
1252
1253 static void __exit ip22zilog_exit(void)
1254 {
1255         int i;
1256
1257         for (i = 0; i < NUM_CHANNELS; i++) {
1258                 struct uart_ip22zilog_port *up = &ip22zilog_port_table[i];
1259
1260                 uart_remove_one_port(&ip22zilog_reg, &up->port);
1261         }
1262
1263         uart_unregister_driver(&ip22zilog_reg);
1264 }
1265
1266 module_init(ip22zilog_init);
1267 module_exit(ip22zilog_exit);
1268
1269 /* David wrote it but I'm to blame for the bugs ...  */
1270 MODULE_AUTHOR("Ralf Baechle <ralf@linux-mips.org>");
1271 MODULE_DESCRIPTION("SGI Zilog serial port driver");
1272 MODULE_LICENSE("GPL");