5e8a27620f6f339045981b5994b4138c69be073a
[linux-3.10.git] / drivers / tc / zs.c
1 /*
2  * decserial.c: Serial port driver for IOASIC DECstations.
3  *
4  * Derived from drivers/sbus/char/sunserial.c by Paul Mackerras.
5  * Derived from drivers/macintosh/macserial.c by Harald Koerfgen.
6  *
7  * DECstation changes
8  * Copyright (C) 1998-2000 Harald Koerfgen
9  * Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005  Maciej W. Rozycki
10  *
11  * For the rest of the code the original Copyright applies:
12  * Copyright (C) 1996 Paul Mackerras (Paul.Mackerras@cs.anu.edu.au)
13  * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
14  *
15  *
16  * Note: for IOASIC systems the wiring is as follows:
17  *
18  * mouse/keyboard:
19  * DIN-7 MJ-4  signal        SCC
20  * 2     1     TxD       <-  A.TxD
21  * 3     4     RxD       ->  A.RxD
22  *
23  * EIA-232/EIA-423:
24  * DB-25 MMJ-6 signal        SCC
25  * 2     2     TxD       <-  B.TxD
26  * 3     5     RxD       ->  B.RxD
27  * 4           RTS       <- ~A.RTS
28  * 5           CTS       -> ~B.CTS
29  * 6     6     DSR       -> ~A.SYNC
30  * 8           CD        -> ~B.DCD
31  * 12          DSRS(DCE) -> ~A.CTS  (*)
32  * 15          TxC       ->  B.TxC
33  * 17          RxC       ->  B.RxC
34  * 20    1     DTR       <- ~A.DTR
35  * 22          RI        -> ~A.DCD
36  * 23          DSRS(DTE) <- ~B.RTS
37  *
38  * (*) EIA-232 defines the signal at this pin to be SCD, while DSRS(DCE)
39  *     is shared with DSRS(DTE) at pin 23.
40  */
41
42 #include <linux/errno.h>
43 #include <linux/signal.h>
44 #include <linux/sched.h>
45 #include <linux/timer.h>
46 #include <linux/interrupt.h>
47 #include <linux/tty.h>
48 #include <linux/tty_flip.h>
49 #include <linux/major.h>
50 #include <linux/string.h>
51 #include <linux/fcntl.h>
52 #include <linux/mm.h>
53 #include <linux/kernel.h>
54 #include <linux/delay.h>
55 #include <linux/init.h>
56 #include <linux/ioport.h>
57 #include <linux/spinlock.h>
58 #ifdef CONFIG_SERIAL_DEC_CONSOLE
59 #include <linux/console.h>
60 #endif
61
62 #include <asm/io.h>
63 #include <asm/pgtable.h>
64 #include <asm/irq.h>
65 #include <asm/system.h>
66 #include <asm/bootinfo.h>
67
68 #include <asm/dec/interrupts.h>
69 #include <asm/dec/ioasic_addrs.h>
70 #include <asm/dec/machtype.h>
71 #include <asm/dec/serial.h>
72 #include <asm/dec/system.h>
73 #include <asm/dec/tc.h>
74
75 #ifdef CONFIG_KGDB
76 #include <asm/kgdb.h>
77 #endif
78 #ifdef CONFIG_MAGIC_SYSRQ
79 #include <linux/sysrq.h>
80 #endif
81
82 #include "zs.h"
83
84 /*
85  * It would be nice to dynamically allocate everything that
86  * depends on NUM_SERIAL, so we could support any number of
87  * Z8530s, but for now...
88  */
89 #define NUM_SERIAL      2               /* Max number of ZS chips supported */
90 #define NUM_CHANNELS    (NUM_SERIAL * 2)        /* 2 channels per chip */
91 #define CHANNEL_A_NR  (zs_parms->channel_a_offset > zs_parms->channel_b_offset)
92                                         /* Number of channel A in the chip */
93 #define ZS_CHAN_IO_SIZE 8
94 #define ZS_CLOCK        7372800         /* Z8530 RTxC input clock rate */
95
96 #define RECOVERY_DELAY  udelay(2)
97
98 struct zs_parms {
99         unsigned long scc0;
100         unsigned long scc1;
101         int channel_a_offset;
102         int channel_b_offset;
103         int irq0;
104         int irq1;
105         int clock;
106 };
107
108 static struct zs_parms *zs_parms;
109
110 #ifdef CONFIG_MACH_DECSTATION
111 static struct zs_parms ds_parms = {
112         scc0 : IOASIC_SCC0,
113         scc1 : IOASIC_SCC1,
114         channel_a_offset : 1,
115         channel_b_offset : 9,
116         irq0 : -1,
117         irq1 : -1,
118         clock : ZS_CLOCK
119 };
120 #endif
121
122 #ifdef CONFIG_MACH_DECSTATION
123 #define DS_BUS_PRESENT (IOASIC)
124 #else
125 #define DS_BUS_PRESENT 0
126 #endif
127
128 #define BUS_PRESENT (DS_BUS_PRESENT)
129
130 DEFINE_SPINLOCK(zs_lock);
131
132 struct dec_zschannel zs_channels[NUM_CHANNELS];
133 struct dec_serial zs_soft[NUM_CHANNELS];
134 int zs_channels_found;
135 struct dec_serial *zs_chain;    /* list of all channels */
136
137 struct tty_struct zs_ttys[NUM_CHANNELS];
138
139 #ifdef CONFIG_SERIAL_DEC_CONSOLE
140 static struct console sercons;
141 #endif
142 #if defined(CONFIG_SERIAL_DEC_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) && \
143    !defined(MODULE)
144 static unsigned long break_pressed; /* break, really ... */
145 #endif
146
147 static unsigned char zs_init_regs[16] __initdata = {
148         0,                              /* write 0 */
149         0,                              /* write 1 */
150         0,                              /* write 2 */
151         0,                              /* write 3 */
152         (X16CLK),                       /* write 4 */
153         0,                              /* write 5 */
154         0, 0, 0,                        /* write 6, 7, 8 */
155         (MIE | DLC | NV),               /* write 9 */
156         (NRZ),                          /* write 10 */
157         (TCBR | RCBR),                  /* write 11 */
158         0, 0,                           /* BRG time constant, write 12 + 13 */
159         (BRSRC | BRENABL),              /* write 14 */
160         0                               /* write 15 */
161 };
162
163 static struct tty_driver *serial_driver;
164
165 /* serial subtype definitions */
166 #define SERIAL_TYPE_NORMAL      1
167
168 /* number of characters left in xmit buffer before we ask for more */
169 #define WAKEUP_CHARS 256
170
171 /*
172  * Debugging.
173  */
174 #undef SERIAL_DEBUG_OPEN
175 #undef SERIAL_DEBUG_FLOW
176 #undef SERIAL_DEBUG_THROTTLE
177 #undef SERIAL_PARANOIA_CHECK
178
179 #undef ZS_DEBUG_REGS
180
181 #ifdef SERIAL_DEBUG_THROTTLE
182 #define _tty_name(tty,buf) tty_name(tty,buf)
183 #endif
184
185 #define RS_STROBE_TIME 10
186 #define RS_ISR_PASS_LIMIT 256
187
188 static void probe_sccs(void);
189 static void change_speed(struct dec_serial *info);
190 static void rs_wait_until_sent(struct tty_struct *tty, int timeout);
191
192 static inline int serial_paranoia_check(struct dec_serial *info,
193                                         char *name, const char *routine)
194 {
195 #ifdef SERIAL_PARANOIA_CHECK
196         static const char *badmagic =
197                 "Warning: bad magic number for serial struct %s in %s\n";
198         static const char *badinfo =
199                 "Warning: null mac_serial for %s in %s\n";
200
201         if (!info) {
202                 printk(badinfo, name, routine);
203                 return 1;
204         }
205         if (info->magic != SERIAL_MAGIC) {
206                 printk(badmagic, name, routine);
207                 return 1;
208         }
209 #endif
210         return 0;
211 }
212
213 /*
214  * This is used to figure out the divisor speeds and the timeouts
215  */
216 static int baud_table[] = {
217         0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
218         9600, 19200, 38400, 57600, 115200, 0 };
219
220 /*
221  * Reading and writing Z8530 registers.
222  */
223 static inline unsigned char read_zsreg(struct dec_zschannel *channel,
224                                        unsigned char reg)
225 {
226         unsigned char retval;
227
228         if (reg != 0) {
229                 *channel->control = reg & 0xf;
230                 fast_iob(); RECOVERY_DELAY;
231         }
232         retval = *channel->control;
233         RECOVERY_DELAY;
234         return retval;
235 }
236
237 static inline void write_zsreg(struct dec_zschannel *channel,
238                                unsigned char reg, unsigned char value)
239 {
240         if (reg != 0) {
241                 *channel->control = reg & 0xf;
242                 fast_iob(); RECOVERY_DELAY;
243         }
244         *channel->control = value;
245         fast_iob(); RECOVERY_DELAY;
246         return;
247 }
248
249 static inline unsigned char read_zsdata(struct dec_zschannel *channel)
250 {
251         unsigned char retval;
252
253         retval = *channel->data;
254         RECOVERY_DELAY;
255         return retval;
256 }
257
258 static inline void write_zsdata(struct dec_zschannel *channel,
259                                 unsigned char value)
260 {
261         *channel->data = value;
262         fast_iob(); RECOVERY_DELAY;
263         return;
264 }
265
266 static inline void load_zsregs(struct dec_zschannel *channel,
267                                unsigned char *regs)
268 {
269 /*      ZS_CLEARERR(channel);
270         ZS_CLEARFIFO(channel); */
271         /* Load 'em up */
272         write_zsreg(channel, R3, regs[R3] & ~RxENABLE);
273         write_zsreg(channel, R5, regs[R5] & ~TxENAB);
274         write_zsreg(channel, R4, regs[R4]);
275         write_zsreg(channel, R9, regs[R9]);
276         write_zsreg(channel, R1, regs[R1]);
277         write_zsreg(channel, R2, regs[R2]);
278         write_zsreg(channel, R10, regs[R10]);
279         write_zsreg(channel, R11, regs[R11]);
280         write_zsreg(channel, R12, regs[R12]);
281         write_zsreg(channel, R13, regs[R13]);
282         write_zsreg(channel, R14, regs[R14]);
283         write_zsreg(channel, R15, regs[R15]);
284         write_zsreg(channel, R3, regs[R3]);
285         write_zsreg(channel, R5, regs[R5]);
286         return;
287 }
288
289 /* Sets or clears DTR/RTS on the requested line */
290 static inline void zs_rtsdtr(struct dec_serial *info, int which, int set)
291 {
292         unsigned long flags;
293
294         spin_lock_irqsave(&zs_lock, flags);
295         if (info->zs_channel != info->zs_chan_a) {
296                 if (set) {
297                         info->zs_chan_a->curregs[5] |= (which & (RTS | DTR));
298                 } else {
299                         info->zs_chan_a->curregs[5] &= ~(which & (RTS | DTR));
300                 }
301                 write_zsreg(info->zs_chan_a, 5, info->zs_chan_a->curregs[5]);
302         }
303         spin_unlock_irqrestore(&zs_lock, flags);
304 }
305
306 /* Utility routines for the Zilog */
307 static inline int get_zsbaud(struct dec_serial *ss)
308 {
309         struct dec_zschannel *channel = ss->zs_channel;
310         int brg;
311
312         /* The baud rate is split up between two 8-bit registers in
313          * what is termed 'BRG time constant' format in my docs for
314          * the chip, it is a function of the clk rate the chip is
315          * receiving which happens to be constant.
316          */
317         brg = (read_zsreg(channel, 13) << 8);
318         brg |= read_zsreg(channel, 12);
319         return BRG_TO_BPS(brg, (zs_parms->clock/(ss->clk_divisor)));
320 }
321
322 /* On receive, this clears errors and the receiver interrupts */
323 static inline void rs_recv_clear(struct dec_zschannel *zsc)
324 {
325         write_zsreg(zsc, 0, ERR_RES);
326         write_zsreg(zsc, 0, RES_H_IUS); /* XXX this is unnecessary */
327 }
328
329 /*
330  * ----------------------------------------------------------------------
331  *
332  * Here starts the interrupt handling routines.  All of the following
333  * subroutines are declared as inline and are folded into
334  * rs_interrupt().  They were separated out for readability's sake.
335  *
336  *                              - Ted Ts'o (tytso@mit.edu), 7-Mar-93
337  * -----------------------------------------------------------------------
338  */
339
340 /*
341  * This routine is used by the interrupt handler to schedule
342  * processing in the software interrupt portion of the driver.
343  */
344 static void rs_sched_event(struct dec_serial *info, int event)
345 {
346         info->event |= 1 << event;
347         tasklet_schedule(&info->tlet);
348 }
349
350 static void receive_chars(struct dec_serial *info, struct pt_regs *regs)
351 {
352         struct tty_struct *tty = info->tty;
353         unsigned char ch, stat, flag;
354
355         while ((read_zsreg(info->zs_channel, R0) & Rx_CH_AV) != 0) {
356
357                 stat = read_zsreg(info->zs_channel, R1);
358                 ch = read_zsdata(info->zs_channel);
359
360                 if (!tty && (!info->hook || !info->hook->rx_char))
361                         continue;
362
363                 flag = TTY_NORMAL;
364                 if (info->tty_break) {
365                         info->tty_break = 0;
366                         flag = TTY_BREAK;
367                         if (info->flags & ZILOG_SAK)
368                                 do_SAK(tty);
369                         /* Ignore the null char got when BREAK is removed.  */
370                         if (ch == 0)
371                                 continue;
372                 } else {
373                         if (stat & Rx_OVR) {
374                                 flag = TTY_OVERRUN;
375                         } else if (stat & FRM_ERR) {
376                                 flag = TTY_FRAME;
377                         } else if (stat & PAR_ERR) {
378                                 flag = TTY_PARITY;
379                         }
380                         if (flag != TTY_NORMAL)
381                                 /* reset the error indication */
382                                 write_zsreg(info->zs_channel, R0, ERR_RES);
383                 }
384
385 #if defined(CONFIG_SERIAL_DEC_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) && \
386    !defined(MODULE)
387                 if (break_pressed && info->line == sercons.index) {
388                         /* Ignore the null char got when BREAK is removed.  */
389                         if (ch == 0)
390                                 continue;
391                         if (time_before(jiffies, break_pressed + HZ * 5)) {
392                                 handle_sysrq(ch, regs, NULL);
393                                 break_pressed = 0;
394                                 continue;
395                         }
396                         break_pressed = 0;
397                 }
398 #endif
399
400                 if (info->hook && info->hook->rx_char) {
401                         (*info->hook->rx_char)(ch, flag);
402                         return;
403                 }
404
405                 tty_insert_flip_char(tty, ch, flag);
406         }
407         if (tty)
408                 tty_flip_buffer_push(tty);
409 }
410
411 static void transmit_chars(struct dec_serial *info)
412 {
413         if ((read_zsreg(info->zs_channel, R0) & Tx_BUF_EMP) == 0)
414                 return;
415         info->tx_active = 0;
416
417         if (info->x_char) {
418                 /* Send next char */
419                 write_zsdata(info->zs_channel, info->x_char);
420                 info->x_char = 0;
421                 info->tx_active = 1;
422                 return;
423         }
424
425         if ((info->xmit_cnt <= 0) || (info->tty && info->tty->stopped)
426             || info->tx_stopped) {
427                 write_zsreg(info->zs_channel, R0, RES_Tx_P);
428                 return;
429         }
430         /* Send char */
431         write_zsdata(info->zs_channel, info->xmit_buf[info->xmit_tail++]);
432         info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
433         info->xmit_cnt--;
434         info->tx_active = 1;
435
436         if (info->xmit_cnt < WAKEUP_CHARS)
437                 rs_sched_event(info, RS_EVENT_WRITE_WAKEUP);
438 }
439
440 static void status_handle(struct dec_serial *info)
441 {
442         unsigned char stat;
443
444         /* Get status from Read Register 0 */
445         stat = read_zsreg(info->zs_channel, R0);
446
447         if ((stat & BRK_ABRT) && !(info->read_reg_zero & BRK_ABRT)) {
448 #if defined(CONFIG_SERIAL_DEC_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) && \
449    !defined(MODULE)
450                 if (info->line == sercons.index) {
451                         if (!break_pressed)
452                                 break_pressed = jiffies;
453                 } else
454 #endif
455                         info->tty_break = 1;
456         }
457
458         if (info->zs_channel != info->zs_chan_a) {
459
460                 /* Check for DCD transitions */
461                 if (info->tty && !C_CLOCAL(info->tty) &&
462                     ((stat ^ info->read_reg_zero) & DCD) != 0 ) {
463                         if (stat & DCD) {
464                                 wake_up_interruptible(&info->open_wait);
465                         } else {
466                                 tty_hangup(info->tty);
467                         }
468                 }
469
470                 /* Check for CTS transitions */
471                 if (info->tty && C_CRTSCTS(info->tty)) {
472                         if ((stat & CTS) != 0) {
473                                 if (info->tx_stopped) {
474                                         info->tx_stopped = 0;
475                                         if (!info->tx_active)
476                                                 transmit_chars(info);
477                                 }
478                         } else {
479                                 info->tx_stopped = 1;
480                         }
481                 }
482
483         }
484
485         /* Clear status condition... */
486         write_zsreg(info->zs_channel, R0, RES_EXT_INT);
487         info->read_reg_zero = stat;
488 }
489
490 /*
491  * This is the serial driver's generic interrupt routine
492  */
493 static irqreturn_t rs_interrupt(int irq, void *dev_id, struct pt_regs *regs)
494 {
495         struct dec_serial *info = (struct dec_serial *) dev_id;
496         irqreturn_t status = IRQ_NONE;
497         unsigned char zs_intreg;
498         int shift;
499
500         /* NOTE: The read register 3, which holds the irq status,
501          *       does so for both channels on each chip.  Although
502          *       the status value itself must be read from the A
503          *       channel and is only valid when read from channel A.
504          *       Yes... broken hardware...
505          */
506 #define CHAN_IRQMASK (CHBRxIP | CHBTxIP | CHBEXT)
507
508         if (info->zs_chan_a == info->zs_channel)
509                 shift = 3;      /* Channel A */
510         else
511                 shift = 0;      /* Channel B */
512
513         for (;;) {
514                 zs_intreg = read_zsreg(info->zs_chan_a, R3) >> shift;
515                 if ((zs_intreg & CHAN_IRQMASK) == 0)
516                         break;
517
518                 status = IRQ_HANDLED;
519
520                 if (zs_intreg & CHBRxIP) {
521                         receive_chars(info, regs);
522                 }
523                 if (zs_intreg & CHBTxIP) {
524                         transmit_chars(info);
525                 }
526                 if (zs_intreg & CHBEXT) {
527                         status_handle(info);
528                 }
529         }
530
531         /* Why do we need this ? */
532         write_zsreg(info->zs_channel, 0, RES_H_IUS);
533
534         return status;
535 }
536
537 #ifdef ZS_DEBUG_REGS
538 void zs_dump (void) {
539         int i, j;
540         for (i = 0; i < zs_channels_found; i++) {
541                 struct dec_zschannel *ch = &zs_channels[i];
542                 if ((long)ch->control == UNI_IO_BASE+UNI_SCC1A_CTRL) {
543                         for (j = 0; j < 15; j++) {
544                                 printk("W%d = 0x%x\t",
545                                        j, (int)ch->curregs[j]);
546                         }
547                         for (j = 0; j < 15; j++) {
548                                 printk("R%d = 0x%x\t",
549                                        j, (int)read_zsreg(ch,j));
550                         }
551                         printk("\n\n");
552                 }
553         }
554 }
555 #endif
556
557 /*
558  * -------------------------------------------------------------------
559  * Here ends the serial interrupt routines.
560  * -------------------------------------------------------------------
561  */
562
563 /*
564  * ------------------------------------------------------------
565  * rs_stop() and rs_start()
566  *
567  * This routines are called before setting or resetting tty->stopped.
568  * ------------------------------------------------------------
569  */
570 static void rs_stop(struct tty_struct *tty)
571 {
572         struct dec_serial *info = (struct dec_serial *)tty->driver_data;
573         unsigned long flags;
574
575         if (serial_paranoia_check(info, tty->name, "rs_stop"))
576                 return;
577
578 #if 1
579         spin_lock_irqsave(&zs_lock, flags);
580         if (info->zs_channel->curregs[5] & TxENAB) {
581                 info->zs_channel->curregs[5] &= ~TxENAB;
582                 write_zsreg(info->zs_channel, 5, info->zs_channel->curregs[5]);
583         }
584         spin_unlock_irqrestore(&zs_lock, flags);
585 #endif
586 }
587
588 static void rs_start(struct tty_struct *tty)
589 {
590         struct dec_serial *info = (struct dec_serial *)tty->driver_data;
591         unsigned long flags;
592
593         if (serial_paranoia_check(info, tty->name, "rs_start"))
594                 return;
595
596         spin_lock_irqsave(&zs_lock, flags);
597 #if 1
598         if (info->xmit_cnt && info->xmit_buf && !(info->zs_channel->curregs[5] & TxENAB)) {
599                 info->zs_channel->curregs[5] |= TxENAB;
600                 write_zsreg(info->zs_channel, 5, info->zs_channel->curregs[5]);
601         }
602 #else
603         if (info->xmit_cnt && info->xmit_buf && !info->tx_active) {
604                 transmit_chars(info);
605         }
606 #endif
607         spin_unlock_irqrestore(&zs_lock, flags);
608 }
609
610 /*
611  * This routine is used to handle the "bottom half" processing for the
612  * serial driver, known also the "software interrupt" processing.
613  * This processing is done at the kernel interrupt level, after the
614  * rs_interrupt() has returned, BUT WITH INTERRUPTS TURNED ON.  This
615  * is where time-consuming activities which can not be done in the
616  * interrupt driver proper are done; the interrupt driver schedules
617  * them using rs_sched_event(), and they get done here.
618  */
619
620 static void do_softint(unsigned long private_)
621 {
622         struct dec_serial       *info = (struct dec_serial *) private_;
623         struct tty_struct       *tty;
624
625         tty = info->tty;
626         if (!tty)
627                 return;
628
629         if (test_and_clear_bit(RS_EVENT_WRITE_WAKEUP, &info->event)) {
630                 tty_wakeup(tty);
631                 wake_up_interruptible(&tty->write_wait);
632         }
633 }
634
635 static int zs_startup(struct dec_serial * info)
636 {
637         unsigned long flags;
638
639         if (info->flags & ZILOG_INITIALIZED)
640                 return 0;
641
642         if (!info->xmit_buf) {
643                 info->xmit_buf = (unsigned char *) get_zeroed_page(GFP_KERNEL);
644                 if (!info->xmit_buf)
645                         return -ENOMEM;
646         }
647
648         spin_lock_irqsave(&zs_lock, flags);
649
650 #ifdef SERIAL_DEBUG_OPEN
651         printk("starting up ttyS%d (irq %d)...", info->line, info->irq);
652 #endif
653
654         /*
655          * Clear the receive FIFO.
656          */
657         ZS_CLEARFIFO(info->zs_channel);
658         info->xmit_fifo_size = 1;
659
660         /*
661          * Clear the interrupt registers.
662          */
663         write_zsreg(info->zs_channel, R0, ERR_RES);
664         write_zsreg(info->zs_channel, R0, RES_H_IUS);
665
666         /*
667          * Set the speed of the serial port
668          */
669         change_speed(info);
670
671         /*
672          * Turn on RTS and DTR.
673          */
674         zs_rtsdtr(info, RTS | DTR, 1);
675
676         /*
677          * Finally, enable sequencing and interrupts
678          */
679         info->zs_channel->curregs[R1] &= ~RxINT_MASK;
680         info->zs_channel->curregs[R1] |= (RxINT_ALL | TxINT_ENAB |
681                                           EXT_INT_ENAB);
682         info->zs_channel->curregs[R3] |= RxENABLE;
683         info->zs_channel->curregs[R5] |= TxENAB;
684         info->zs_channel->curregs[R15] |= (DCDIE | CTSIE | TxUIE | BRKIE);
685         write_zsreg(info->zs_channel, R1, info->zs_channel->curregs[R1]);
686         write_zsreg(info->zs_channel, R3, info->zs_channel->curregs[R3]);
687         write_zsreg(info->zs_channel, R5, info->zs_channel->curregs[R5]);
688         write_zsreg(info->zs_channel, R15, info->zs_channel->curregs[R15]);
689
690         /*
691          * And clear the interrupt registers again for luck.
692          */
693         write_zsreg(info->zs_channel, R0, ERR_RES);
694         write_zsreg(info->zs_channel, R0, RES_H_IUS);
695
696         /* Save the current value of RR0 */
697         info->read_reg_zero = read_zsreg(info->zs_channel, R0);
698
699         if (info->tty)
700                 clear_bit(TTY_IO_ERROR, &info->tty->flags);
701         info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
702
703         info->flags |= ZILOG_INITIALIZED;
704         spin_unlock_irqrestore(&zs_lock, flags);
705         return 0;
706 }
707
708 /*
709  * This routine will shutdown a serial port; interrupts are disabled, and
710  * DTR is dropped if the hangup on close termio flag is on.
711  */
712 static void shutdown(struct dec_serial * info)
713 {
714         unsigned long   flags;
715
716         if (!(info->flags & ZILOG_INITIALIZED))
717                 return;
718
719 #ifdef SERIAL_DEBUG_OPEN
720         printk("Shutting down serial port %d (irq %d)....", info->line,
721                info->irq);
722 #endif
723
724         spin_lock_irqsave(&zs_lock, flags);
725
726         if (info->xmit_buf) {
727                 free_page((unsigned long) info->xmit_buf);
728                 info->xmit_buf = 0;
729         }
730
731         info->zs_channel->curregs[1] = 0;
732         write_zsreg(info->zs_channel, 1, info->zs_channel->curregs[1]); /* no interrupts */
733
734         info->zs_channel->curregs[3] &= ~RxENABLE;
735         write_zsreg(info->zs_channel, 3, info->zs_channel->curregs[3]);
736
737         info->zs_channel->curregs[5] &= ~TxENAB;
738         write_zsreg(info->zs_channel, 5, info->zs_channel->curregs[5]);
739         if (!info->tty || C_HUPCL(info->tty)) {
740                 zs_rtsdtr(info, RTS | DTR, 0);
741         }
742
743         if (info->tty)
744                 set_bit(TTY_IO_ERROR, &info->tty->flags);
745
746         info->flags &= ~ZILOG_INITIALIZED;
747         spin_unlock_irqrestore(&zs_lock, flags);
748 }
749
750 /*
751  * This routine is called to set the UART divisor registers to match
752  * the specified baud rate for a serial port.
753  */
754 static void change_speed(struct dec_serial *info)
755 {
756         unsigned cflag;
757         int     i;
758         int     brg, bits;
759         unsigned long flags;
760
761         if (!info->hook) {
762                 if (!info->tty || !info->tty->termios)
763                         return;
764                 cflag = info->tty->termios->c_cflag;
765                 if (!info->port)
766                         return;
767         } else {
768                 cflag = info->hook->cflags;
769         }
770
771         i = cflag & CBAUD;
772         if (i & CBAUDEX) {
773                 i &= ~CBAUDEX;
774                 if (i < 1 || i > 2) {
775                         if (!info->hook)
776                                 info->tty->termios->c_cflag &= ~CBAUDEX;
777                         else
778                                 info->hook->cflags &= ~CBAUDEX;
779                 } else
780                         i += 15;
781         }
782
783         spin_lock_irqsave(&zs_lock, flags);
784         info->zs_baud = baud_table[i];
785         if (info->zs_baud) {
786                 brg = BPS_TO_BRG(info->zs_baud, zs_parms->clock/info->clk_divisor);
787                 info->zs_channel->curregs[12] = (brg & 255);
788                 info->zs_channel->curregs[13] = ((brg >> 8) & 255);
789                 zs_rtsdtr(info, DTR, 1);
790         } else {
791                 zs_rtsdtr(info, RTS | DTR, 0);
792                 return;
793         }
794
795         /* byte size and parity */
796         info->zs_channel->curregs[3] &= ~RxNBITS_MASK;
797         info->zs_channel->curregs[5] &= ~TxNBITS_MASK;
798         switch (cflag & CSIZE) {
799         case CS5:
800                 bits = 7;
801                 info->zs_channel->curregs[3] |= Rx5;
802                 info->zs_channel->curregs[5] |= Tx5;
803                 break;
804         case CS6:
805                 bits = 8;
806                 info->zs_channel->curregs[3] |= Rx6;
807                 info->zs_channel->curregs[5] |= Tx6;
808                 break;
809         case CS7:
810                 bits = 9;
811                 info->zs_channel->curregs[3] |= Rx7;
812                 info->zs_channel->curregs[5] |= Tx7;
813                 break;
814         case CS8:
815         default: /* defaults to 8 bits */
816                 bits = 10;
817                 info->zs_channel->curregs[3] |= Rx8;
818                 info->zs_channel->curregs[5] |= Tx8;
819                 break;
820         }
821
822         info->timeout = ((info->xmit_fifo_size*HZ*bits) / info->zs_baud);
823         info->timeout += HZ/50;         /* Add .02 seconds of slop */
824
825         info->zs_channel->curregs[4] &= ~(SB_MASK | PAR_ENA | PAR_EVEN);
826         if (cflag & CSTOPB) {
827                 info->zs_channel->curregs[4] |= SB2;
828         } else {
829                 info->zs_channel->curregs[4] |= SB1;
830         }
831         if (cflag & PARENB) {
832                 info->zs_channel->curregs[4] |= PAR_ENA;
833         }
834         if (!(cflag & PARODD)) {
835                 info->zs_channel->curregs[4] |= PAR_EVEN;
836         }
837
838         if (!(cflag & CLOCAL)) {
839                 if (!(info->zs_channel->curregs[15] & DCDIE))
840                         info->read_reg_zero = read_zsreg(info->zs_channel, 0);
841                 info->zs_channel->curregs[15] |= DCDIE;
842         } else
843                 info->zs_channel->curregs[15] &= ~DCDIE;
844         if (cflag & CRTSCTS) {
845                 info->zs_channel->curregs[15] |= CTSIE;
846                 if ((read_zsreg(info->zs_channel, 0) & CTS) == 0)
847                         info->tx_stopped = 1;
848         } else {
849                 info->zs_channel->curregs[15] &= ~CTSIE;
850                 info->tx_stopped = 0;
851         }
852
853         /* Load up the new values */
854         load_zsregs(info->zs_channel, info->zs_channel->curregs);
855
856         spin_unlock_irqrestore(&zs_lock, flags);
857 }
858
859 static void rs_flush_chars(struct tty_struct *tty)
860 {
861         struct dec_serial *info = (struct dec_serial *)tty->driver_data;
862         unsigned long flags;
863
864         if (serial_paranoia_check(info, tty->name, "rs_flush_chars"))
865                 return;
866
867         if (info->xmit_cnt <= 0 || tty->stopped || info->tx_stopped ||
868             !info->xmit_buf)
869                 return;
870
871         /* Enable transmitter */
872         spin_lock_irqsave(&zs_lock, flags);
873         transmit_chars(info);
874         spin_unlock_irqrestore(&zs_lock, flags);
875 }
876
877 static int rs_write(struct tty_struct * tty,
878                     const unsigned char *buf, int count)
879 {
880         int     c, total = 0;
881         struct dec_serial *info = (struct dec_serial *)tty->driver_data;
882         unsigned long flags;
883
884         if (serial_paranoia_check(info, tty->name, "rs_write"))
885                 return 0;
886
887         if (!tty || !info->xmit_buf)
888                 return 0;
889
890         while (1) {
891                 spin_lock_irqsave(&zs_lock, flags);
892                 c = min(count, min(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
893                                    SERIAL_XMIT_SIZE - info->xmit_head));
894                 if (c <= 0)
895                         break;
896
897                 memcpy(info->xmit_buf + info->xmit_head, buf, c);
898                 info->xmit_head = (info->xmit_head + c) & (SERIAL_XMIT_SIZE-1);
899                 info->xmit_cnt += c;
900                 spin_unlock_irqrestore(&zs_lock, flags);
901                 buf += c;
902                 count -= c;
903                 total += c;
904         }
905
906         if (info->xmit_cnt && !tty->stopped && !info->tx_stopped
907             && !info->tx_active)
908                 transmit_chars(info);
909         spin_unlock_irqrestore(&zs_lock, flags);
910         return total;
911 }
912
913 static int rs_write_room(struct tty_struct *tty)
914 {
915         struct dec_serial *info = (struct dec_serial *)tty->driver_data;
916         int     ret;
917
918         if (serial_paranoia_check(info, tty->name, "rs_write_room"))
919                 return 0;
920         ret = SERIAL_XMIT_SIZE - info->xmit_cnt - 1;
921         if (ret < 0)
922                 ret = 0;
923         return ret;
924 }
925
926 static int rs_chars_in_buffer(struct tty_struct *tty)
927 {
928         struct dec_serial *info = (struct dec_serial *)tty->driver_data;
929
930         if (serial_paranoia_check(info, tty->name, "rs_chars_in_buffer"))
931                 return 0;
932         return info->xmit_cnt;
933 }
934
935 static void rs_flush_buffer(struct tty_struct *tty)
936 {
937         struct dec_serial *info = (struct dec_serial *)tty->driver_data;
938
939         if (serial_paranoia_check(info, tty->name, "rs_flush_buffer"))
940                 return;
941         spin_lock_irq(&zs_lock);
942         info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
943         spin_unlock_irq(&zs_lock);
944         tty_wakeup(tty);
945 }
946
947 /*
948  * ------------------------------------------------------------
949  * rs_throttle()
950  *
951  * This routine is called by the upper-layer tty layer to signal that
952  * incoming characters should be throttled.
953  * ------------------------------------------------------------
954  */
955 static void rs_throttle(struct tty_struct * tty)
956 {
957         struct dec_serial *info = (struct dec_serial *)tty->driver_data;
958         unsigned long flags;
959
960 #ifdef SERIAL_DEBUG_THROTTLE
961         char    buf[64];
962
963         printk("throttle %s: %d....\n", _tty_name(tty, buf),
964                tty->ldisc.chars_in_buffer(tty));
965 #endif
966
967         if (serial_paranoia_check(info, tty->name, "rs_throttle"))
968                 return;
969
970         if (I_IXOFF(tty)) {
971                 spin_lock_irqsave(&zs_lock, flags);
972                 info->x_char = STOP_CHAR(tty);
973                 if (!info->tx_active)
974                         transmit_chars(info);
975                 spin_unlock_irqrestore(&zs_lock, flags);
976         }
977
978         if (C_CRTSCTS(tty)) {
979                 zs_rtsdtr(info, RTS, 0);
980         }
981 }
982
983 static void rs_unthrottle(struct tty_struct * tty)
984 {
985         struct dec_serial *info = (struct dec_serial *)tty->driver_data;
986         unsigned long flags;
987
988 #ifdef SERIAL_DEBUG_THROTTLE
989         char    buf[64];
990
991         printk("unthrottle %s: %d....\n", _tty_name(tty, buf),
992                tty->ldisc.chars_in_buffer(tty));
993 #endif
994
995         if (serial_paranoia_check(info, tty->name, "rs_unthrottle"))
996                 return;
997
998         if (I_IXOFF(tty)) {
999                 spin_lock_irqsave(&zs_lock, flags);
1000                 if (info->x_char)
1001                         info->x_char = 0;
1002                 else {
1003                         info->x_char = START_CHAR(tty);
1004                         if (!info->tx_active)
1005                                 transmit_chars(info);
1006                 }
1007                 spin_unlock_irqrestore(&zs_lock, flags);
1008         }
1009
1010         if (C_CRTSCTS(tty)) {
1011                 zs_rtsdtr(info, RTS, 1);
1012         }
1013 }
1014
1015 /*
1016  * ------------------------------------------------------------
1017  * rs_ioctl() and friends
1018  * ------------------------------------------------------------
1019  */
1020
1021 static int get_serial_info(struct dec_serial * info,
1022                            struct serial_struct * retinfo)
1023 {
1024         struct serial_struct tmp;
1025
1026         if (!retinfo)
1027                 return -EFAULT;
1028         memset(&tmp, 0, sizeof(tmp));
1029         tmp.type = info->type;
1030         tmp.line = info->line;
1031         tmp.port = info->port;
1032         tmp.irq = info->irq;
1033         tmp.flags = info->flags;
1034         tmp.baud_base = info->baud_base;
1035         tmp.close_delay = info->close_delay;
1036         tmp.closing_wait = info->closing_wait;
1037         tmp.custom_divisor = info->custom_divisor;
1038         return copy_to_user(retinfo,&tmp,sizeof(*retinfo)) ? -EFAULT : 0;
1039 }
1040
1041 static int set_serial_info(struct dec_serial * info,
1042                            struct serial_struct * new_info)
1043 {
1044         struct serial_struct new_serial;
1045         struct dec_serial old_info;
1046         int                     retval = 0;
1047
1048         if (!new_info)
1049                 return -EFAULT;
1050         copy_from_user(&new_serial,new_info,sizeof(new_serial));
1051         old_info = *info;
1052
1053         if (!capable(CAP_SYS_ADMIN)) {
1054                 if ((new_serial.baud_base != info->baud_base) ||
1055                     (new_serial.type != info->type) ||
1056                     (new_serial.close_delay != info->close_delay) ||
1057                     ((new_serial.flags & ~ZILOG_USR_MASK) !=
1058                      (info->flags & ~ZILOG_USR_MASK)))
1059                         return -EPERM;
1060                 info->flags = ((info->flags & ~ZILOG_USR_MASK) |
1061                                (new_serial.flags & ZILOG_USR_MASK));
1062                 info->custom_divisor = new_serial.custom_divisor;
1063                 goto check_and_exit;
1064         }
1065
1066         if (info->count > 1)
1067                 return -EBUSY;
1068
1069         /*
1070          * OK, past this point, all the error checking has been done.
1071          * At this point, we start making changes.....
1072          */
1073
1074         info->baud_base = new_serial.baud_base;
1075         info->flags = ((info->flags & ~ZILOG_FLAGS) |
1076                         (new_serial.flags & ZILOG_FLAGS));
1077         info->type = new_serial.type;
1078         info->close_delay = new_serial.close_delay;
1079         info->closing_wait = new_serial.closing_wait;
1080
1081 check_and_exit:
1082         retval = zs_startup(info);
1083         return retval;
1084 }
1085
1086 /*
1087  * get_lsr_info - get line status register info
1088  *
1089  * Purpose: Let user call ioctl() to get info when the UART physically
1090  *          is emptied.  On bus types like RS485, the transmitter must
1091  *          release the bus after transmitting. This must be done when
1092  *          the transmit shift register is empty, not be done when the
1093  *          transmit holding register is empty.  This functionality
1094  *          allows an RS485 driver to be written in user space.
1095  */
1096 static int get_lsr_info(struct dec_serial * info, unsigned int *value)
1097 {
1098         unsigned char status;
1099
1100         spin_lock(&zs_lock);
1101         status = read_zsreg(info->zs_channel, 0);
1102         spin_unlock_irq(&zs_lock);
1103         put_user(status,value);
1104         return 0;
1105 }
1106
1107 static int rs_tiocmget(struct tty_struct *tty, struct file *file)
1108 {
1109         struct dec_serial * info = (struct dec_serial *)tty->driver_data;
1110         unsigned char control, status_a, status_b;
1111         unsigned int result;
1112
1113         if (info->hook)
1114                 return -ENODEV;
1115
1116         if (serial_paranoia_check(info, tty->name, __FUNCTION__))
1117                 return -ENODEV;
1118
1119         if (tty->flags & (1 << TTY_IO_ERROR))
1120                 return -EIO;
1121
1122         if (info->zs_channel == info->zs_chan_a)
1123                 result = 0;
1124         else {
1125                 spin_lock(&zs_lock);
1126                 control = info->zs_chan_a->curregs[5];
1127                 status_a = read_zsreg(info->zs_chan_a, 0);
1128                 status_b = read_zsreg(info->zs_channel, 0);
1129                 spin_unlock_irq(&zs_lock);
1130                 result =  ((control  & RTS) ? TIOCM_RTS: 0)
1131                         | ((control  & DTR) ? TIOCM_DTR: 0)
1132                         | ((status_b & DCD) ? TIOCM_CAR: 0)
1133                         | ((status_a & DCD) ? TIOCM_RNG: 0)
1134                         | ((status_a & SYNC_HUNT) ? TIOCM_DSR: 0)
1135                         | ((status_b & CTS) ? TIOCM_CTS: 0);
1136         }
1137         return result;
1138 }
1139
1140 static int rs_tiocmset(struct tty_struct *tty, struct file *file,
1141                        unsigned int set, unsigned int clear)
1142 {
1143         struct dec_serial * info = (struct dec_serial *)tty->driver_data;
1144
1145         if (info->hook)
1146                 return -ENODEV;
1147
1148         if (serial_paranoia_check(info, tty->name, __FUNCTION__))
1149                 return -ENODEV;
1150
1151         if (tty->flags & (1 << TTY_IO_ERROR))
1152                 return -EIO;
1153
1154         if (info->zs_channel == info->zs_chan_a)
1155                 return 0;
1156
1157         spin_lock(&zs_lock);
1158         if (set & TIOCM_RTS)
1159                 info->zs_chan_a->curregs[5] |= RTS;
1160         if (set & TIOCM_DTR)
1161                 info->zs_chan_a->curregs[5] |= DTR;
1162         if (clear & TIOCM_RTS)
1163                 info->zs_chan_a->curregs[5] &= ~RTS;
1164         if (clear & TIOCM_DTR)
1165                 info->zs_chan_a->curregs[5] &= ~DTR;
1166         write_zsreg(info->zs_chan_a, 5, info->zs_chan_a->curregs[5]);
1167         spin_unlock_irq(&zs_lock);
1168         return 0;
1169 }
1170
1171 /*
1172  * rs_break - turn transmit break condition on/off
1173  */
1174 static void rs_break(struct tty_struct *tty, int break_state)
1175 {
1176         struct dec_serial *info = (struct dec_serial *) tty->driver_data;
1177         unsigned long flags;
1178
1179         if (serial_paranoia_check(info, tty->name, "rs_break"))
1180                 return;
1181         if (!info->port)
1182                 return;
1183
1184         spin_lock_irqsave(&zs_lock, flags);
1185         if (break_state == -1)
1186                 info->zs_channel->curregs[5] |= SND_BRK;
1187         else
1188                 info->zs_channel->curregs[5] &= ~SND_BRK;
1189         write_zsreg(info->zs_channel, 5, info->zs_channel->curregs[5]);
1190         spin_unlock_irqrestore(&zs_lock, flags);
1191 }
1192
1193 static int rs_ioctl(struct tty_struct *tty, struct file * file,
1194                     unsigned int cmd, unsigned long arg)
1195 {
1196         struct dec_serial * info = (struct dec_serial *)tty->driver_data;
1197
1198         if (info->hook)
1199                 return -ENODEV;
1200
1201         if (serial_paranoia_check(info, tty->name, "rs_ioctl"))
1202                 return -ENODEV;
1203
1204         if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
1205             (cmd != TIOCSERCONFIG) && (cmd != TIOCSERGWILD)  &&
1206             (cmd != TIOCSERSWILD) && (cmd != TIOCSERGSTRUCT)) {
1207                 if (tty->flags & (1 << TTY_IO_ERROR))
1208                     return -EIO;
1209         }
1210
1211         switch (cmd) {
1212         case TIOCGSERIAL:
1213                 if (!access_ok(VERIFY_WRITE, (void *)arg,
1214                                sizeof(struct serial_struct)))
1215                         return -EFAULT;
1216                 return get_serial_info(info, (struct serial_struct *)arg);
1217
1218         case TIOCSSERIAL:
1219                 return set_serial_info(info, (struct serial_struct *)arg);
1220
1221         case TIOCSERGETLSR:                     /* Get line status register */
1222                 if (!access_ok(VERIFY_WRITE, (void *)arg,
1223                                sizeof(unsigned int)))
1224                         return -EFAULT;
1225                 return get_lsr_info(info, (unsigned int *)arg);
1226
1227         case TIOCSERGSTRUCT:
1228                 if (!access_ok(VERIFY_WRITE, (void *)arg,
1229                                sizeof(struct dec_serial)))
1230                         return -EFAULT;
1231                 copy_from_user((struct dec_serial *)arg, info,
1232                                sizeof(struct dec_serial));
1233                 return 0;
1234
1235         default:
1236                 return -ENOIOCTLCMD;
1237         }
1238         return 0;
1239 }
1240
1241 static void rs_set_termios(struct tty_struct *tty, struct termios *old_termios)
1242 {
1243         struct dec_serial *info = (struct dec_serial *)tty->driver_data;
1244         int was_stopped;
1245
1246         if (tty->termios->c_cflag == old_termios->c_cflag)
1247                 return;
1248         was_stopped = info->tx_stopped;
1249
1250         change_speed(info);
1251
1252         if (was_stopped && !info->tx_stopped)
1253                 rs_start(tty);
1254 }
1255
1256 /*
1257  * ------------------------------------------------------------
1258  * rs_close()
1259  *
1260  * This routine is called when the serial port gets closed.
1261  * Wait for the last remaining data to be sent.
1262  * ------------------------------------------------------------
1263  */
1264 static void rs_close(struct tty_struct *tty, struct file * filp)
1265 {
1266         struct dec_serial * info = (struct dec_serial *)tty->driver_data;
1267         unsigned long flags;
1268
1269         if (!info || serial_paranoia_check(info, tty->name, "rs_close"))
1270                 return;
1271
1272         spin_lock_irqsave(&zs_lock, flags);
1273
1274         if (tty_hung_up_p(filp)) {
1275                 spin_unlock_irqrestore(&zs_lock, flags);
1276                 return;
1277         }
1278
1279 #ifdef SERIAL_DEBUG_OPEN
1280         printk("rs_close ttyS%d, count = %d\n", info->line, info->count);
1281 #endif
1282         if ((tty->count == 1) && (info->count != 1)) {
1283                 /*
1284                  * Uh, oh.  tty->count is 1, which means that the tty
1285                  * structure will be freed.  Info->count should always
1286                  * be one in these conditions.  If it's greater than
1287                  * one, we've got real problems, since it means the
1288                  * serial port won't be shutdown.
1289                  */
1290                 printk("rs_close: bad serial port count; tty->count is 1, "
1291                        "info->count is %d\n", info->count);
1292                 info->count = 1;
1293         }
1294         if (--info->count < 0) {
1295                 printk("rs_close: bad serial port count for ttyS%d: %d\n",
1296                        info->line, info->count);
1297                 info->count = 0;
1298         }
1299         if (info->count) {
1300                 spin_unlock_irqrestore(&zs_lock, flags);
1301                 return;
1302         }
1303         info->flags |= ZILOG_CLOSING;
1304         /*
1305          * Now we wait for the transmit buffer to clear; and we notify
1306          * the line discipline to only process XON/XOFF characters.
1307          */
1308         tty->closing = 1;
1309         if (info->closing_wait != ZILOG_CLOSING_WAIT_NONE)
1310                 tty_wait_until_sent(tty, info->closing_wait);
1311         /*
1312          * At this point we stop accepting input.  To do this, we
1313          * disable the receiver and receive interrupts.
1314          */
1315         info->zs_channel->curregs[3] &= ~RxENABLE;
1316         write_zsreg(info->zs_channel, 3, info->zs_channel->curregs[3]);
1317         info->zs_channel->curregs[1] = 0;       /* disable any rx ints */
1318         write_zsreg(info->zs_channel, 1, info->zs_channel->curregs[1]);
1319         ZS_CLEARFIFO(info->zs_channel);
1320         if (info->flags & ZILOG_INITIALIZED) {
1321                 /*
1322                  * Before we drop DTR, make sure the SCC transmitter
1323                  * has completely drained.
1324                  */
1325                 rs_wait_until_sent(tty, info->timeout);
1326         }
1327
1328         shutdown(info);
1329         if (tty->driver->flush_buffer)
1330                 tty->driver->flush_buffer(tty);
1331         tty_ldisc_flush(tty);
1332         tty->closing = 0;
1333         info->event = 0;
1334         info->tty = 0;
1335         if (info->blocked_open) {
1336                 if (info->close_delay) {
1337                         msleep_interruptible(jiffies_to_msecs(info->close_delay));
1338                 }
1339                 wake_up_interruptible(&info->open_wait);
1340         }
1341         info->flags &= ~(ZILOG_NORMAL_ACTIVE|ZILOG_CLOSING);
1342         wake_up_interruptible(&info->close_wait);
1343         spin_unlock_irqrestore(&zs_lock, flags);
1344 }
1345
1346 /*
1347  * rs_wait_until_sent() --- wait until the transmitter is empty
1348  */
1349 static void rs_wait_until_sent(struct tty_struct *tty, int timeout)
1350 {
1351         struct dec_serial *info = (struct dec_serial *) tty->driver_data;
1352         unsigned long orig_jiffies;
1353         int char_time;
1354
1355         if (serial_paranoia_check(info, tty->name, "rs_wait_until_sent"))
1356                 return;
1357
1358         orig_jiffies = jiffies;
1359         /*
1360          * Set the check interval to be 1/5 of the estimated time to
1361          * send a single character, and make it at least 1.  The check
1362          * interval should also be less than the timeout.
1363          */
1364         char_time = (info->timeout - HZ/50) / info->xmit_fifo_size;
1365         char_time = char_time / 5;
1366         if (char_time == 0)
1367                 char_time = 1;
1368         if (timeout)
1369                 char_time = min(char_time, timeout);
1370         while ((read_zsreg(info->zs_channel, 1) & Tx_BUF_EMP) == 0) {
1371                 msleep_interruptible(jiffies_to_msecs(char_time));
1372                 if (signal_pending(current))
1373                         break;
1374                 if (timeout && time_after(jiffies, orig_jiffies + timeout))
1375                         break;
1376         }
1377         current->state = TASK_RUNNING;
1378 }
1379
1380 /*
1381  * rs_hangup() --- called by tty_hangup() when a hangup is signaled.
1382  */
1383 static void rs_hangup(struct tty_struct *tty)
1384 {
1385         struct dec_serial * info = (struct dec_serial *)tty->driver_data;
1386
1387         if (serial_paranoia_check(info, tty->name, "rs_hangup"))
1388                 return;
1389
1390         rs_flush_buffer(tty);
1391         shutdown(info);
1392         info->event = 0;
1393         info->count = 0;
1394         info->flags &= ~ZILOG_NORMAL_ACTIVE;
1395         info->tty = 0;
1396         wake_up_interruptible(&info->open_wait);
1397 }
1398
1399 /*
1400  * ------------------------------------------------------------
1401  * rs_open() and friends
1402  * ------------------------------------------------------------
1403  */
1404 static int block_til_ready(struct tty_struct *tty, struct file * filp,
1405                            struct dec_serial *info)
1406 {
1407         DECLARE_WAITQUEUE(wait, current);
1408         int             retval;
1409         int             do_clocal = 0;
1410
1411         /*
1412          * If the device is in the middle of being closed, then block
1413          * until it's done, and then try again.
1414          */
1415         if (info->flags & ZILOG_CLOSING) {
1416                 interruptible_sleep_on(&info->close_wait);
1417 #ifdef SERIAL_DO_RESTART
1418                 return ((info->flags & ZILOG_HUP_NOTIFY) ?
1419                         -EAGAIN : -ERESTARTSYS);
1420 #else
1421                 return -EAGAIN;
1422 #endif
1423         }
1424
1425         /*
1426          * If non-blocking mode is set, or the port is not enabled,
1427          * then make the check up front and then exit.
1428          */
1429         if ((filp->f_flags & O_NONBLOCK) ||
1430             (tty->flags & (1 << TTY_IO_ERROR))) {
1431                 info->flags |= ZILOG_NORMAL_ACTIVE;
1432                 return 0;
1433         }
1434
1435         if (tty->termios->c_cflag & CLOCAL)
1436                 do_clocal = 1;
1437
1438         /*
1439          * Block waiting for the carrier detect and the line to become
1440          * free (i.e., not in use by the callout).  While we are in
1441          * this loop, info->count is dropped by one, so that
1442          * rs_close() knows when to free things.  We restore it upon
1443          * exit, either normal or abnormal.
1444          */
1445         retval = 0;
1446         add_wait_queue(&info->open_wait, &wait);
1447 #ifdef SERIAL_DEBUG_OPEN
1448         printk("block_til_ready before block: ttyS%d, count = %d\n",
1449                info->line, info->count);
1450 #endif
1451         spin_lock(&zs_lock);
1452         if (!tty_hung_up_p(filp))
1453                 info->count--;
1454         spin_unlock_irq(&zs_lock);
1455         info->blocked_open++;
1456         while (1) {
1457                 spin_lock(&zs_lock);
1458                 if (tty->termios->c_cflag & CBAUD)
1459                         zs_rtsdtr(info, RTS | DTR, 1);
1460                 spin_unlock_irq(&zs_lock);
1461                 set_current_state(TASK_INTERRUPTIBLE);
1462                 if (tty_hung_up_p(filp) ||
1463                     !(info->flags & ZILOG_INITIALIZED)) {
1464 #ifdef SERIAL_DO_RESTART
1465                         if (info->flags & ZILOG_HUP_NOTIFY)
1466                                 retval = -EAGAIN;
1467                         else
1468                                 retval = -ERESTARTSYS;
1469 #else
1470                         retval = -EAGAIN;
1471 #endif
1472                         break;
1473                 }
1474                 if (!(info->flags & ZILOG_CLOSING) &&
1475                     (do_clocal || (read_zsreg(info->zs_channel, 0) & DCD)))
1476                         break;
1477                 if (signal_pending(current)) {
1478                         retval = -ERESTARTSYS;
1479                         break;
1480                 }
1481 #ifdef SERIAL_DEBUG_OPEN
1482                 printk("block_til_ready blocking: ttyS%d, count = %d\n",
1483                        info->line, info->count);
1484 #endif
1485                 schedule();
1486         }
1487         current->state = TASK_RUNNING;
1488         remove_wait_queue(&info->open_wait, &wait);
1489         if (!tty_hung_up_p(filp))
1490                 info->count++;
1491         info->blocked_open--;
1492 #ifdef SERIAL_DEBUG_OPEN
1493         printk("block_til_ready after blocking: ttyS%d, count = %d\n",
1494                info->line, info->count);
1495 #endif
1496         if (retval)
1497                 return retval;
1498         info->flags |= ZILOG_NORMAL_ACTIVE;
1499         return 0;
1500 }
1501
1502 /*
1503  * This routine is called whenever a serial port is opened.  It
1504  * enables interrupts for a serial port, linking in its ZILOG structure into
1505  * the IRQ chain.   It also performs the serial-specific
1506  * initialization for the tty structure.
1507  */
1508 static int rs_open(struct tty_struct *tty, struct file * filp)
1509 {
1510         struct dec_serial       *info;
1511         int                     retval, line;
1512
1513         line = tty->index;
1514         if ((line < 0) || (line >= zs_channels_found))
1515                 return -ENODEV;
1516         info = zs_soft + line;
1517
1518         if (info->hook)
1519                 return -ENODEV;
1520
1521         if (serial_paranoia_check(info, tty->name, "rs_open"))
1522                 return -ENODEV;
1523 #ifdef SERIAL_DEBUG_OPEN
1524         printk("rs_open %s, count = %d\n", tty->name, info->count);
1525 #endif
1526
1527         info->count++;
1528         tty->driver_data = info;
1529         info->tty = tty;
1530
1531         /*
1532          * If the port is the middle of closing, bail out now
1533          */
1534         if (tty_hung_up_p(filp) ||
1535             (info->flags & ZILOG_CLOSING)) {
1536                 if (info->flags & ZILOG_CLOSING)
1537                         interruptible_sleep_on(&info->close_wait);
1538 #ifdef SERIAL_DO_RESTART
1539                 return ((info->flags & ZILOG_HUP_NOTIFY) ?
1540                         -EAGAIN : -ERESTARTSYS);
1541 #else
1542                 return -EAGAIN;
1543 #endif
1544         }
1545
1546         /*
1547          * Start up serial port
1548          */
1549         retval = zs_startup(info);
1550         if (retval)
1551                 return retval;
1552
1553         retval = block_til_ready(tty, filp, info);
1554         if (retval) {
1555 #ifdef SERIAL_DEBUG_OPEN
1556                 printk("rs_open returning after block_til_ready with %d\n",
1557                        retval);
1558 #endif
1559                 return retval;
1560         }
1561
1562 #ifdef CONFIG_SERIAL_DEC_CONSOLE
1563         if (sercons.cflag && sercons.index == line) {
1564                 tty->termios->c_cflag = sercons.cflag;
1565                 sercons.cflag = 0;
1566                 change_speed(info);
1567         }
1568 #endif
1569
1570 #ifdef SERIAL_DEBUG_OPEN
1571         printk("rs_open %s successful...", tty->name);
1572 #endif
1573 /* tty->low_latency = 1; */
1574         return 0;
1575 }
1576
1577 /* Finally, routines used to initialize the serial driver. */
1578
1579 static void __init show_serial_version(void)
1580 {
1581         printk("DECstation Z8530 serial driver version 0.09\n");
1582 }
1583
1584 /*  Initialize Z8530s zs_channels
1585  */
1586
1587 static void __init probe_sccs(void)
1588 {
1589         struct dec_serial **pp;
1590         int i, n, n_chips = 0, n_channels, chip, channel;
1591         unsigned long flags;
1592
1593         /*
1594          * did we get here by accident?
1595          */
1596         if(!BUS_PRESENT) {
1597                 printk("Not on JUNKIO machine, skipping probe_sccs\n");
1598                 return;
1599         }
1600
1601         switch(mips_machtype) {
1602 #ifdef CONFIG_MACH_DECSTATION
1603         case MACH_DS5000_2X0:
1604         case MACH_DS5900:
1605                 n_chips = 2;
1606                 zs_parms = &ds_parms;
1607                 zs_parms->irq0 = dec_interrupt[DEC_IRQ_SCC0];
1608                 zs_parms->irq1 = dec_interrupt[DEC_IRQ_SCC1];
1609                 break;
1610         case MACH_DS5000_1XX:
1611                 n_chips = 2;
1612                 zs_parms = &ds_parms;
1613                 zs_parms->irq0 = dec_interrupt[DEC_IRQ_SCC0];
1614                 zs_parms->irq1 = dec_interrupt[DEC_IRQ_SCC1];
1615                 break;
1616         case MACH_DS5000_XX:
1617                 n_chips = 1;
1618                 zs_parms = &ds_parms;
1619                 zs_parms->irq0 = dec_interrupt[DEC_IRQ_SCC0];
1620                 break;
1621 #endif
1622         default:
1623                 panic("zs: unsupported bus");
1624         }
1625         if (!zs_parms)
1626                 panic("zs: uninitialized parms");
1627
1628         pp = &zs_chain;
1629
1630         n_channels = 0;
1631
1632         for (chip = 0; chip < n_chips; chip++) {
1633                 for (channel = 0; channel <= 1; channel++) {
1634                         /*
1635                          * The sccs reside on the high byte of the 16 bit IOBUS
1636                          */
1637                         zs_channels[n_channels].control =
1638                                 (volatile void *)CKSEG1ADDR(dec_kn_slot_base +
1639                           (0 == chip ? zs_parms->scc0 : zs_parms->scc1) +
1640                           (0 == channel ? zs_parms->channel_a_offset :
1641                                           zs_parms->channel_b_offset));
1642                         zs_channels[n_channels].data =
1643                                 zs_channels[n_channels].control + 4;
1644
1645 #ifndef CONFIG_SERIAL_DEC_CONSOLE
1646                         /*
1647                          * We're called early and memory managment isn't up, yet.
1648                          * Thus request_region would fail.
1649                          */
1650                         if (!request_region((unsigned long)
1651                                          zs_channels[n_channels].control,
1652                                          ZS_CHAN_IO_SIZE, "SCC"))
1653                                 panic("SCC I/O region is not free");
1654 #endif
1655                         zs_soft[n_channels].zs_channel = &zs_channels[n_channels];
1656                         /* HACK alert! */
1657                         if (!(chip & 1))
1658                                 zs_soft[n_channels].irq = zs_parms->irq0;
1659                         else
1660                                 zs_soft[n_channels].irq = zs_parms->irq1;
1661
1662                         /*
1663                          *  Identification of channel A. Location of channel A
1664                          *  inside chip depends on mapping of internal address
1665                          *  the chip decodes channels by.
1666                          *  CHANNEL_A_NR returns either 0 (in case of
1667                          *  DECstations) or 1 (in case of Baget).
1668                          */
1669                         if (CHANNEL_A_NR == channel)
1670                                 zs_soft[n_channels].zs_chan_a =
1671                                     &zs_channels[n_channels+1-2*CHANNEL_A_NR];
1672                         else
1673                                 zs_soft[n_channels].zs_chan_a =
1674                                     &zs_channels[n_channels];
1675
1676                         *pp = &zs_soft[n_channels];
1677                         pp = &zs_soft[n_channels].zs_next;
1678                         n_channels++;
1679                 }
1680         }
1681
1682         *pp = 0;
1683         zs_channels_found = n_channels;
1684
1685         for (n = 0; n < zs_channels_found; n++) {
1686                 for (i = 0; i < 16; i++) {
1687                         zs_soft[n].zs_channel->curregs[i] = zs_init_regs[i];
1688                 }
1689         }
1690
1691         spin_lock_irqsave(&zs_lock, flags);
1692         for (n = 0; n < zs_channels_found; n++) {
1693                 if (n % 2 == 0) {
1694                         write_zsreg(zs_soft[n].zs_chan_a, R9, FHWRES);
1695                         udelay(10);
1696                         write_zsreg(zs_soft[n].zs_chan_a, R9, 0);
1697                 }
1698                 load_zsregs(zs_soft[n].zs_channel,
1699                             zs_soft[n].zs_channel->curregs);
1700         }
1701         spin_unlock_irqrestore(&zs_lock, flags);
1702 }
1703
1704 static struct tty_operations serial_ops = {
1705         .open = rs_open,
1706         .close = rs_close,
1707         .write = rs_write,
1708         .flush_chars = rs_flush_chars,
1709         .write_room = rs_write_room,
1710         .chars_in_buffer = rs_chars_in_buffer,
1711         .flush_buffer = rs_flush_buffer,
1712         .ioctl = rs_ioctl,
1713         .throttle = rs_throttle,
1714         .unthrottle = rs_unthrottle,
1715         .set_termios = rs_set_termios,
1716         .stop = rs_stop,
1717         .start = rs_start,
1718         .hangup = rs_hangup,
1719         .break_ctl = rs_break,
1720         .wait_until_sent = rs_wait_until_sent,
1721         .tiocmget = rs_tiocmget,
1722         .tiocmset = rs_tiocmset,
1723 };
1724
1725 /* zs_init inits the driver */
1726 int __init zs_init(void)
1727 {
1728         int channel, i;
1729         struct dec_serial *info;
1730
1731         if(!BUS_PRESENT)
1732                 return -ENODEV;
1733
1734         /* Find out how many Z8530 SCCs we have */
1735         if (zs_chain == 0)
1736                 probe_sccs();
1737         serial_driver = alloc_tty_driver(zs_channels_found);
1738         if (!serial_driver)
1739                 return -ENOMEM;
1740
1741         show_serial_version();
1742
1743         /* Initialize the tty_driver structure */
1744         /* Not all of this is exactly right for us. */
1745
1746         serial_driver->owner = THIS_MODULE;
1747         serial_driver->name = "ttyS";
1748         serial_driver->major = TTY_MAJOR;
1749         serial_driver->minor_start = 64;
1750         serial_driver->type = TTY_DRIVER_TYPE_SERIAL;
1751         serial_driver->subtype = SERIAL_TYPE_NORMAL;
1752         serial_driver->init_termios = tty_std_termios;
1753         serial_driver->init_termios.c_cflag =
1754                 B9600 | CS8 | CREAD | HUPCL | CLOCAL;
1755         serial_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
1756         tty_set_operations(serial_driver, &serial_ops);
1757
1758         if (tty_register_driver(serial_driver))
1759                 panic("Couldn't register serial driver");
1760
1761         for (info = zs_chain, i = 0; info; info = info->zs_next, i++) {
1762
1763                 /* Needed before interrupts are enabled. */
1764                 info->tty = 0;
1765                 info->x_char = 0;
1766
1767                 if (info->hook && info->hook->init_info) {
1768                         (*info->hook->init_info)(info);
1769                         continue;
1770                 }
1771
1772                 info->magic = SERIAL_MAGIC;
1773                 info->port = (int) info->zs_channel->control;
1774                 info->line = i;
1775                 info->custom_divisor = 16;
1776                 info->close_delay = 50;
1777                 info->closing_wait = 3000;
1778                 info->event = 0;
1779                 info->count = 0;
1780                 info->blocked_open = 0;
1781                 tasklet_init(&info->tlet, do_softint, (unsigned long)info);
1782                 init_waitqueue_head(&info->open_wait);
1783                 init_waitqueue_head(&info->close_wait);
1784                 printk("ttyS%02d at 0x%08x (irq = %d) is a Z85C30 SCC\n",
1785                        info->line, info->port, info->irq);
1786                 tty_register_device(serial_driver, info->line, NULL);
1787
1788         }
1789
1790         for (channel = 0; channel < zs_channels_found; ++channel) {
1791                 zs_soft[channel].clk_divisor = 16;
1792                 zs_soft[channel].zs_baud = get_zsbaud(&zs_soft[channel]);
1793
1794                 if (request_irq(zs_soft[channel].irq, rs_interrupt, IRQF_SHARED,
1795                                 "scc", &zs_soft[channel]))
1796                         printk(KERN_ERR "decserial: can't get irq %d\n",
1797                                zs_soft[channel].irq);
1798
1799                 if (zs_soft[channel].hook) {
1800                         zs_startup(&zs_soft[channel]);
1801                         if (zs_soft[channel].hook->init_channel)
1802                                 (*zs_soft[channel].hook->init_channel)
1803                                         (&zs_soft[channel]);
1804                 }
1805         }
1806
1807         return 0;
1808 }
1809
1810 /*
1811  * polling I/O routines
1812  */
1813 static int zs_poll_tx_char(void *handle, unsigned char ch)
1814 {
1815         struct dec_serial *info = handle;
1816         struct dec_zschannel *chan = info->zs_channel;
1817         int    ret;
1818
1819         if(chan) {
1820                 int loops = 10000;
1821
1822                 while (loops && !(read_zsreg(chan, 0) & Tx_BUF_EMP))
1823                         loops--;
1824
1825                 if (loops) {
1826                         write_zsdata(chan, ch);
1827                         ret = 0;
1828                 } else
1829                         ret = -EAGAIN;
1830
1831                 return ret;
1832         } else
1833                 return -ENODEV;
1834 }
1835
1836 static int zs_poll_rx_char(void *handle)
1837 {
1838         struct dec_serial *info = handle;
1839         struct dec_zschannel *chan = info->zs_channel;
1840         int    ret;
1841
1842         if(chan) {
1843                 int loops = 10000;
1844
1845                 while (loops && !(read_zsreg(chan, 0) & Rx_CH_AV))
1846                         loops--;
1847
1848                 if (loops)
1849                         ret = read_zsdata(chan);
1850                 else
1851                         ret = -EAGAIN;
1852
1853                 return ret;
1854         } else
1855                 return -ENODEV;
1856 }
1857
1858 int register_zs_hook(unsigned int channel, struct dec_serial_hook *hook)
1859 {
1860         struct dec_serial *info = &zs_soft[channel];
1861
1862         if (info->hook) {
1863                 printk("%s: line %d has already a hook registered\n",
1864                        __FUNCTION__, channel);
1865
1866                 return 0;
1867         } else {
1868                 hook->poll_rx_char = zs_poll_rx_char;
1869                 hook->poll_tx_char = zs_poll_tx_char;
1870                 info->hook = hook;
1871
1872                 return 1;
1873         }
1874 }
1875
1876 int unregister_zs_hook(unsigned int channel)
1877 {
1878         struct dec_serial *info = &zs_soft[channel];
1879
1880         if (info->hook) {
1881                 info->hook = NULL;
1882                 return 1;
1883         } else {
1884                 printk("%s: trying to unregister hook on line %d,"
1885                        " but none is registered\n", __FUNCTION__, channel);
1886                 return 0;
1887         }
1888 }
1889
1890 /*
1891  * ------------------------------------------------------------
1892  * Serial console driver
1893  * ------------------------------------------------------------
1894  */
1895 #ifdef CONFIG_SERIAL_DEC_CONSOLE
1896
1897
1898 /*
1899  *      Print a string to the serial port trying not to disturb
1900  *      any possible real use of the port...
1901  */
1902 static void serial_console_write(struct console *co, const char *s,
1903                                  unsigned count)
1904 {
1905         struct dec_serial *info;
1906         int i;
1907
1908         info = zs_soft + co->index;
1909
1910         for (i = 0; i < count; i++, s++) {
1911                 if(*s == '\n')
1912                         zs_poll_tx_char(info, '\r');
1913                 zs_poll_tx_char(info, *s);
1914         }
1915 }
1916
1917 static struct tty_driver *serial_console_device(struct console *c, int *index)
1918 {
1919         *index = c->index;
1920         return serial_driver;
1921 }
1922
1923 /*
1924  *      Setup initial baud/bits/parity. We do two things here:
1925  *      - construct a cflag setting for the first rs_open()
1926  *      - initialize the serial port
1927  *      Return non-zero if we didn't find a serial port.
1928  */
1929 static int __init serial_console_setup(struct console *co, char *options)
1930 {
1931         struct dec_serial *info;
1932         int baud = 9600;
1933         int bits = 8;
1934         int parity = 'n';
1935         int cflag = CREAD | HUPCL | CLOCAL;
1936         int clk_divisor = 16;
1937         int brg;
1938         char *s;
1939         unsigned long flags;
1940
1941         if(!BUS_PRESENT)
1942                 return -ENODEV;
1943
1944         info = zs_soft + co->index;
1945
1946         if (zs_chain == 0)
1947                 probe_sccs();
1948
1949         info->is_cons = 1;
1950
1951         if (options) {
1952                 baud = simple_strtoul(options, NULL, 10);
1953                 s = options;
1954                 while(*s >= '0' && *s <= '9')
1955                         s++;
1956                 if (*s)
1957                         parity = *s++;
1958                 if (*s)
1959                         bits   = *s - '0';
1960         }
1961
1962         /*
1963          *      Now construct a cflag setting.
1964          */
1965         switch(baud) {
1966         case 1200:
1967                 cflag |= B1200;
1968                 break;
1969         case 2400:
1970                 cflag |= B2400;
1971                 break;
1972         case 4800:
1973                 cflag |= B4800;
1974                 break;
1975         case 19200:
1976                 cflag |= B19200;
1977                 break;
1978         case 38400:
1979                 cflag |= B38400;
1980                 break;
1981         case 57600:
1982                 cflag |= B57600;
1983                 break;
1984         case 115200:
1985                 cflag |= B115200;
1986                 break;
1987         case 9600:
1988         default:
1989                 cflag |= B9600;
1990                 /*
1991                  * Set this to a sane value to prevent a divide error.
1992                  */
1993                 baud  = 9600;
1994                 break;
1995         }
1996         switch(bits) {
1997         case 7:
1998                 cflag |= CS7;
1999                 break;
2000         default:
2001         case 8:
2002                 cflag |= CS8;
2003                 break;
2004         }
2005         switch(parity) {
2006         case 'o': case 'O':
2007                 cflag |= PARODD;
2008                 break;
2009         case 'e': case 'E':
2010                 cflag |= PARENB;
2011                 break;
2012         }
2013         co->cflag = cflag;
2014
2015         spin_lock_irqsave(&zs_lock, flags);
2016
2017         /*
2018          * Set up the baud rate generator.
2019          */
2020         brg = BPS_TO_BRG(baud, zs_parms->clock / clk_divisor);
2021         info->zs_channel->curregs[R12] = (brg & 255);
2022         info->zs_channel->curregs[R13] = ((brg >> 8) & 255);
2023
2024         /*
2025          * Set byte size and parity.
2026          */
2027         if (bits == 7) {
2028                 info->zs_channel->curregs[R3] |= Rx7;
2029                 info->zs_channel->curregs[R5] |= Tx7;
2030         } else {
2031                 info->zs_channel->curregs[R3] |= Rx8;
2032                 info->zs_channel->curregs[R5] |= Tx8;
2033         }
2034         if (cflag & PARENB) {
2035                 info->zs_channel->curregs[R4] |= PAR_ENA;
2036         }
2037         if (!(cflag & PARODD)) {
2038                 info->zs_channel->curregs[R4] |= PAR_EVEN;
2039         }
2040         info->zs_channel->curregs[R4] |= SB1;
2041
2042         /*
2043          * Turn on RTS and DTR.
2044          */
2045         zs_rtsdtr(info, RTS | DTR, 1);
2046
2047         /*
2048          * Finally, enable sequencing.
2049          */
2050         info->zs_channel->curregs[R3] |= RxENABLE;
2051         info->zs_channel->curregs[R5] |= TxENAB;
2052
2053         /*
2054          * Clear the interrupt registers.
2055          */
2056         write_zsreg(info->zs_channel, R0, ERR_RES);
2057         write_zsreg(info->zs_channel, R0, RES_H_IUS);
2058
2059         /*
2060          * Load up the new values.
2061          */
2062         load_zsregs(info->zs_channel, info->zs_channel->curregs);
2063
2064         /* Save the current value of RR0 */
2065         info->read_reg_zero = read_zsreg(info->zs_channel, R0);
2066
2067         zs_soft[co->index].clk_divisor = clk_divisor;
2068         zs_soft[co->index].zs_baud = get_zsbaud(&zs_soft[co->index]);
2069
2070         spin_unlock_irqrestore(&zs_lock, flags);
2071
2072         return 0;
2073 }
2074
2075 static struct console sercons = {
2076         .name           = "ttyS",
2077         .write          = serial_console_write,
2078         .device         = serial_console_device,
2079         .setup          = serial_console_setup,
2080         .flags          = CON_PRINTBUFFER,
2081         .index          = -1,
2082 };
2083
2084 /*
2085  *      Register console.
2086  */
2087 void __init zs_serial_console_init(void)
2088 {
2089         register_console(&sercons);
2090 }
2091 #endif /* ifdef CONFIG_SERIAL_DEC_CONSOLE */
2092
2093 #ifdef CONFIG_KGDB
2094 struct dec_zschannel *zs_kgdbchan;
2095 static unsigned char scc_inittab[] = {
2096         9,  0x80,       /* reset A side (CHRA) */
2097         13, 0,          /* set baud rate divisor */
2098         12, 1,
2099         14, 1,          /* baud rate gen enable, src=rtxc (BRENABL) */
2100         11, 0x50,       /* clocks = br gen (RCBR | TCBR) */
2101         5,  0x6a,       /* tx 8 bits, assert RTS (Tx8 | TxENAB | RTS) */
2102         4,  0x44,       /* x16 clock, 1 stop (SB1 | X16CLK)*/
2103         3,  0xc1,       /* rx enable, 8 bits (RxENABLE | Rx8)*/
2104 };
2105
2106 /* These are for receiving and sending characters under the kgdb
2107  * source level kernel debugger.
2108  */
2109 void putDebugChar(char kgdb_char)
2110 {
2111         struct dec_zschannel *chan = zs_kgdbchan;
2112         while ((read_zsreg(chan, 0) & Tx_BUF_EMP) == 0)
2113                 RECOVERY_DELAY;
2114         write_zsdata(chan, kgdb_char);
2115 }
2116 char getDebugChar(void)
2117 {
2118         struct dec_zschannel *chan = zs_kgdbchan;
2119         while((read_zsreg(chan, 0) & Rx_CH_AV) == 0)
2120                 eieio(); /*barrier();*/
2121         return read_zsdata(chan);
2122 }
2123 void kgdb_interruptible(int yes)
2124 {
2125         struct dec_zschannel *chan = zs_kgdbchan;
2126         int one, nine;
2127         nine = read_zsreg(chan, 9);
2128         if (yes == 1) {
2129                 one = EXT_INT_ENAB|RxINT_ALL;
2130                 nine |= MIE;
2131                 printk("turning serial ints on\n");
2132         } else {
2133                 one = RxINT_DISAB;
2134                 nine &= ~MIE;
2135                 printk("turning serial ints off\n");
2136         }
2137         write_zsreg(chan, 1, one);
2138         write_zsreg(chan, 9, nine);
2139 }
2140
2141 static int kgdbhook_init_channel(void *handle)
2142 {
2143         return 0;
2144 }
2145
2146 static void kgdbhook_init_info(void *handle)
2147 {
2148 }
2149
2150 static void kgdbhook_rx_char(void *handle, unsigned char ch, unsigned char fl)
2151 {
2152         struct dec_serial *info = handle;
2153
2154         if (fl != TTY_NORMAL)
2155                 return;
2156         if (ch == 0x03 || ch == '$')
2157                 breakpoint();
2158 }
2159
2160 /* This sets up the serial port we're using, and turns on
2161  * interrupts for that channel, so kgdb is usable once we're done.
2162  */
2163 static inline void kgdb_chaninit(struct dec_zschannel *ms, int intson, int bps)
2164 {
2165         int brg;
2166         int i, x;
2167         volatile char *sccc = ms->control;
2168         brg = BPS_TO_BRG(bps, zs_parms->clock/16);
2169         printk("setting bps on kgdb line to %d [brg=%x]\n", bps, brg);
2170         for (i = 20000; i != 0; --i) {
2171                 x = *sccc; eieio();
2172         }
2173         for (i = 0; i < sizeof(scc_inittab); ++i) {
2174                 write_zsreg(ms, scc_inittab[i], scc_inittab[i+1]);
2175                 i++;
2176         }
2177 }
2178 /* This is called at boot time to prime the kgdb serial debugging
2179  * serial line.  The 'tty_num' argument is 0 for /dev/ttya and 1
2180  * for /dev/ttyb which is determined in setup_arch() from the
2181  * boot command line flags.
2182  */
2183 struct dec_serial_hook zs_kgdbhook = {
2184         .init_channel   = kgdbhook_init_channel,
2185         .init_info      = kgdbhook_init_info,
2186         .rx_char        = kgdbhook_rx_char,
2187         .cflags         = B38400 | CS8 | CLOCAL,
2188 }
2189
2190 void __init zs_kgdb_hook(int tty_num)
2191 {
2192         /* Find out how many Z8530 SCCs we have */
2193         if (zs_chain == 0)
2194                 probe_sccs();
2195         zs_soft[tty_num].zs_channel = &zs_channels[tty_num];
2196         zs_kgdbchan = zs_soft[tty_num].zs_channel;
2197         zs_soft[tty_num].change_needed = 0;
2198         zs_soft[tty_num].clk_divisor = 16;
2199         zs_soft[tty_num].zs_baud = 38400;
2200         zs_soft[tty_num].hook = &zs_kgdbhook; /* This runs kgdb */
2201         /* Turn on transmitter/receiver at 8-bits/char */
2202         kgdb_chaninit(zs_soft[tty_num].zs_channel, 1, 38400);
2203         printk("KGDB: on channel %d initialized\n", tty_num);
2204         set_debug_traps(); /* init stub */
2205 }
2206 #endif /* ifdef CONFIG_KGDB */