[PATCH] powerpc: fix trigger handling in the new irq code
[linux-2.6.git] / drivers / char / hvsi.c
1 /*
2  * Copyright (C) 2004 Hollis Blanchard <hollisb@us.ibm.com>, IBM
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
17  */
18
19 /* Host Virtual Serial Interface (HVSI) is a protocol between the hosted OS
20  * and the service processor on IBM pSeries servers. On these servers, there
21  * are no serial ports under the OS's control, and sometimes there is no other
22  * console available either. However, the service processor has two standard
23  * serial ports, so this over-complicated protocol allows the OS to control
24  * those ports by proxy.
25  *
26  * Besides data, the procotol supports the reading/writing of the serial
27  * port's DTR line, and the reading of the CD line. This is to allow the OS to
28  * control a modem attached to the service processor's serial port. Note that
29  * the OS cannot change the speed of the port through this protocol.
30  */
31
32 #undef DEBUG
33
34 #include <linux/console.h>
35 #include <linux/ctype.h>
36 #include <linux/delay.h>
37 #include <linux/init.h>
38 #include <linux/interrupt.h>
39 #include <linux/module.h>
40 #include <linux/major.h>
41 #include <linux/kernel.h>
42 #include <linux/sched.h>
43 #include <linux/spinlock.h>
44 #include <linux/sysrq.h>
45 #include <linux/tty.h>
46 #include <linux/tty_flip.h>
47 #include <asm/hvcall.h>
48 #include <asm/hvconsole.h>
49 #include <asm/prom.h>
50 #include <asm/uaccess.h>
51 #include <asm/vio.h>
52 #include <asm/param.h>
53
54 #define HVSI_MAJOR      229
55 #define HVSI_MINOR      128
56 #define MAX_NR_HVSI_CONSOLES 4
57
58 #define HVSI_TIMEOUT (5*HZ)
59 #define HVSI_VERSION 1
60 #define HVSI_MAX_PACKET 256
61 #define HVSI_MAX_READ 16
62 #define HVSI_MAX_OUTGOING_DATA 12
63 #define N_OUTBUF 12
64
65 /*
66  * we pass data via two 8-byte registers, so we would like our char arrays
67  * properly aligned for those loads.
68  */
69 #define __ALIGNED__     __attribute__((__aligned__(sizeof(long))))
70
71 struct hvsi_struct {
72         struct work_struct writer;
73         struct work_struct handshaker;
74         wait_queue_head_t emptyq; /* woken when outbuf is emptied */
75         wait_queue_head_t stateq; /* woken when HVSI state changes */
76         spinlock_t lock;
77         int index;
78         struct tty_struct *tty;
79         unsigned int count;
80         uint8_t throttle_buf[128];
81         uint8_t outbuf[N_OUTBUF]; /* to implement write_room and chars_in_buffer */
82         /* inbuf is for packet reassembly. leave a little room for leftovers. */
83         uint8_t inbuf[HVSI_MAX_PACKET + HVSI_MAX_READ];
84         uint8_t *inbuf_end;
85         int n_throttle;
86         int n_outbuf;
87         uint32_t vtermno;
88         uint32_t virq;
89         atomic_t seqno; /* HVSI packet sequence number */
90         uint16_t mctrl;
91         uint8_t state;  /* HVSI protocol state */
92         uint8_t flags;
93 #ifdef CONFIG_MAGIC_SYSRQ
94         uint8_t sysrq;
95 #endif /* CONFIG_MAGIC_SYSRQ */
96 };
97 static struct hvsi_struct hvsi_ports[MAX_NR_HVSI_CONSOLES];
98
99 static struct tty_driver *hvsi_driver;
100 static int hvsi_count;
101 static int (*hvsi_wait)(struct hvsi_struct *hp, int state);
102
103 enum HVSI_PROTOCOL_STATE {
104         HVSI_CLOSED,
105         HVSI_WAIT_FOR_VER_RESPONSE,
106         HVSI_WAIT_FOR_VER_QUERY,
107         HVSI_OPEN,
108         HVSI_WAIT_FOR_MCTRL_RESPONSE,
109         HVSI_FSP_DIED,
110 };
111 #define HVSI_CONSOLE 0x1
112
113 #define VS_DATA_PACKET_HEADER           0xff
114 #define VS_CONTROL_PACKET_HEADER        0xfe
115 #define VS_QUERY_PACKET_HEADER          0xfd
116 #define VS_QUERY_RESPONSE_PACKET_HEADER 0xfc
117
118 /* control verbs */
119 #define VSV_SET_MODEM_CTL    1 /* to service processor only */
120 #define VSV_MODEM_CTL_UPDATE 2 /* from service processor only */
121 #define VSV_CLOSE_PROTOCOL   3
122
123 /* query verbs */
124 #define VSV_SEND_VERSION_NUMBER 1
125 #define VSV_SEND_MODEM_CTL_STATUS 2
126
127 /* yes, these masks are not consecutive. */
128 #define HVSI_TSDTR 0x01
129 #define HVSI_TSCD  0x20
130
131 struct hvsi_header {
132         uint8_t  type;
133         uint8_t  len;
134         uint16_t seqno;
135 } __attribute__((packed));
136
137 struct hvsi_data {
138         uint8_t  type;
139         uint8_t  len;
140         uint16_t seqno;
141         uint8_t  data[HVSI_MAX_OUTGOING_DATA];
142 } __attribute__((packed));
143
144 struct hvsi_control {
145         uint8_t  type;
146         uint8_t  len;
147         uint16_t seqno;
148         uint16_t verb;
149         /* optional depending on verb: */
150         uint32_t word;
151         uint32_t mask;
152 } __attribute__((packed));
153
154 struct hvsi_query {
155         uint8_t  type;
156         uint8_t  len;
157         uint16_t seqno;
158         uint16_t verb;
159 } __attribute__((packed));
160
161 struct hvsi_query_response {
162         uint8_t  type;
163         uint8_t  len;
164         uint16_t seqno;
165         uint16_t verb;
166         uint16_t query_seqno;
167         union {
168                 uint8_t  version;
169                 uint32_t mctrl_word;
170         } u;
171 } __attribute__((packed));
172
173
174
175 static inline int is_console(struct hvsi_struct *hp)
176 {
177         return hp->flags & HVSI_CONSOLE;
178 }
179
180 static inline int is_open(struct hvsi_struct *hp)
181 {
182         /* if we're waiting for an mctrl then we're already open */
183         return (hp->state == HVSI_OPEN)
184                         || (hp->state == HVSI_WAIT_FOR_MCTRL_RESPONSE);
185 }
186
187 static inline void print_state(struct hvsi_struct *hp)
188 {
189 #ifdef DEBUG
190         static const char *state_names[] = {
191                 "HVSI_CLOSED",
192                 "HVSI_WAIT_FOR_VER_RESPONSE",
193                 "HVSI_WAIT_FOR_VER_QUERY",
194                 "HVSI_OPEN",
195                 "HVSI_WAIT_FOR_MCTRL_RESPONSE",
196                 "HVSI_FSP_DIED",
197         };
198         const char *name = state_names[hp->state];
199
200         if (hp->state > ARRAY_SIZE(state_names))
201                 name = "UNKNOWN";
202
203         pr_debug("hvsi%i: state = %s\n", hp->index, name);
204 #endif /* DEBUG */
205 }
206
207 static inline void __set_state(struct hvsi_struct *hp, int state)
208 {
209         hp->state = state;
210         print_state(hp);
211         wake_up_all(&hp->stateq);
212 }
213
214 static inline void set_state(struct hvsi_struct *hp, int state)
215 {
216         unsigned long flags;
217
218         spin_lock_irqsave(&hp->lock, flags);
219         __set_state(hp, state);
220         spin_unlock_irqrestore(&hp->lock, flags);
221 }
222
223 static inline int len_packet(const uint8_t *packet)
224 {
225         return (int)((struct hvsi_header *)packet)->len;
226 }
227
228 static inline int is_header(const uint8_t *packet)
229 {
230         struct hvsi_header *header = (struct hvsi_header *)packet;
231         return header->type >= VS_QUERY_RESPONSE_PACKET_HEADER;
232 }
233
234 static inline int got_packet(const struct hvsi_struct *hp, uint8_t *packet)
235 {
236         if (hp->inbuf_end < packet + sizeof(struct hvsi_header))
237                 return 0; /* don't even have the packet header */
238
239         if (hp->inbuf_end < (packet + len_packet(packet)))
240                 return 0; /* don't have the rest of the packet */
241
242         return 1;
243 }
244
245 /* shift remaining bytes in packetbuf down */
246 static void compact_inbuf(struct hvsi_struct *hp, uint8_t *read_to)
247 {
248         int remaining = (int)(hp->inbuf_end - read_to);
249
250         pr_debug("%s: %i chars remain\n", __FUNCTION__, remaining);
251
252         if (read_to != hp->inbuf)
253                 memmove(hp->inbuf, read_to, remaining);
254
255         hp->inbuf_end = hp->inbuf + remaining;
256 }
257
258 #ifdef DEBUG
259 #define dbg_dump_packet(packet) dump_packet(packet)
260 #define dbg_dump_hex(data, len) dump_hex(data, len)
261 #else
262 #define dbg_dump_packet(packet) do { } while (0)
263 #define dbg_dump_hex(data, len) do { } while (0)
264 #endif
265
266 static void dump_hex(const uint8_t *data, int len)
267 {
268         int i;
269
270         printk("    ");
271         for (i=0; i < len; i++)
272                 printk("%.2x", data[i]);
273
274         printk("\n    ");
275         for (i=0; i < len; i++) {
276                 if (isprint(data[i]))
277                         printk("%c", data[i]);
278                 else
279                         printk(".");
280         }
281         printk("\n");
282 }
283
284 static void dump_packet(uint8_t *packet)
285 {
286         struct hvsi_header *header = (struct hvsi_header *)packet;
287
288         printk("type 0x%x, len %i, seqno %i:\n", header->type, header->len,
289                         header->seqno);
290
291         dump_hex(packet, header->len);
292 }
293
294 static int hvsi_read(struct hvsi_struct *hp, char *buf, int count)
295 {
296         unsigned long got;
297
298         got = hvc_get_chars(hp->vtermno, buf, count);
299
300         return got;
301 }
302
303 static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet,
304         struct tty_struct **to_hangup, struct hvsi_struct **to_handshake)
305 {
306         struct hvsi_control *header = (struct hvsi_control *)packet;
307
308         switch (header->verb) {
309                 case VSV_MODEM_CTL_UPDATE:
310                         if ((header->word & HVSI_TSCD) == 0) {
311                                 /* CD went away; no more connection */
312                                 pr_debug("hvsi%i: CD dropped\n", hp->index);
313                                 hp->mctrl &= TIOCM_CD;
314                                 if (!(hp->tty->flags & CLOCAL))
315                                         *to_hangup = hp->tty;
316                         }
317                         break;
318                 case VSV_CLOSE_PROTOCOL:
319                         pr_debug("hvsi%i: service processor came back\n", hp->index);
320                         if (hp->state != HVSI_CLOSED) {
321                                 *to_handshake = hp;
322                         }
323                         break;
324                 default:
325                         printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ",
326                                 hp->index);
327                         dump_packet(packet);
328                         break;
329         }
330 }
331
332 static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet)
333 {
334         struct hvsi_query_response *resp = (struct hvsi_query_response *)packet;
335
336         switch (hp->state) {
337                 case HVSI_WAIT_FOR_VER_RESPONSE:
338                         __set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
339                         break;
340                 case HVSI_WAIT_FOR_MCTRL_RESPONSE:
341                         hp->mctrl = 0;
342                         if (resp->u.mctrl_word & HVSI_TSDTR)
343                                 hp->mctrl |= TIOCM_DTR;
344                         if (resp->u.mctrl_word & HVSI_TSCD)
345                                 hp->mctrl |= TIOCM_CD;
346                         __set_state(hp, HVSI_OPEN);
347                         break;
348                 default:
349                         printk(KERN_ERR "hvsi%i: unexpected query response: ", hp->index);
350                         dump_packet(packet);
351                         break;
352         }
353 }
354
355 /* respond to service processor's version query */
356 static int hvsi_version_respond(struct hvsi_struct *hp, uint16_t query_seqno)
357 {
358         struct hvsi_query_response packet __ALIGNED__;
359         int wrote;
360
361         packet.type = VS_QUERY_RESPONSE_PACKET_HEADER;
362         packet.len = sizeof(struct hvsi_query_response);
363         packet.seqno = atomic_inc_return(&hp->seqno);
364         packet.verb = VSV_SEND_VERSION_NUMBER;
365         packet.u.version = HVSI_VERSION;
366         packet.query_seqno = query_seqno+1;
367
368         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
369         dbg_dump_hex((uint8_t*)&packet, packet.len);
370
371         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
372         if (wrote != packet.len) {
373                 printk(KERN_ERR "hvsi%i: couldn't send query response!\n",
374                         hp->index);
375                 return -EIO;
376         }
377
378         return 0;
379 }
380
381 static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet)
382 {
383         struct hvsi_query *query = (struct hvsi_query *)packet;
384
385         switch (hp->state) {
386                 case HVSI_WAIT_FOR_VER_QUERY:
387                         hvsi_version_respond(hp, query->seqno);
388                         __set_state(hp, HVSI_OPEN);
389                         break;
390                 default:
391                         printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index);
392                         dump_packet(packet);
393                         break;
394         }
395 }
396
397 static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len)
398 {
399         int i;
400
401         for (i=0; i < len; i++) {
402                 char c = buf[i];
403 #ifdef CONFIG_MAGIC_SYSRQ
404                 if (c == '\0') {
405                         hp->sysrq = 1;
406                         continue;
407                 } else if (hp->sysrq) {
408                         handle_sysrq(c, NULL, hp->tty);
409                         hp->sysrq = 0;
410                         continue;
411                 }
412 #endif /* CONFIG_MAGIC_SYSRQ */
413                 tty_insert_flip_char(hp->tty, c, 0);
414         }
415 }
416
417 /*
418  * We could get 252 bytes of data at once here. But the tty layer only
419  * throttles us at TTY_THRESHOLD_THROTTLE (128) bytes, so we could overflow
420  * it. Accordingly we won't send more than 128 bytes at a time to the flip
421  * buffer, which will give the tty buffer a chance to throttle us. Should the
422  * value of TTY_THRESHOLD_THROTTLE change in n_tty.c, this code should be
423  * revisited.
424  */
425 #define TTY_THRESHOLD_THROTTLE 128
426 static struct tty_struct *hvsi_recv_data(struct hvsi_struct *hp,
427                 const uint8_t *packet)
428 {
429         const struct hvsi_header *header = (const struct hvsi_header *)packet;
430         const uint8_t *data = packet + sizeof(struct hvsi_header);
431         int datalen = header->len - sizeof(struct hvsi_header);
432         int overflow = datalen - TTY_THRESHOLD_THROTTLE;
433
434         pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data);
435
436         if (datalen == 0)
437                 return NULL;
438
439         if (overflow > 0) {
440                 pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __FUNCTION__);
441                 datalen = TTY_THRESHOLD_THROTTLE;
442         }
443
444         hvsi_insert_chars(hp, data, datalen);
445
446         if (overflow > 0) {
447                 /*
448                  * we still have more data to deliver, so we need to save off the
449                  * overflow and send it later
450                  */
451                 pr_debug("%s: deferring overflow\n", __FUNCTION__);
452                 memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow);
453                 hp->n_throttle = overflow;
454         }
455
456         return hp->tty;
457 }
458
459 /*
460  * Returns true/false indicating data successfully read from hypervisor.
461  * Used both to get packets for tty connections and to advance the state
462  * machine during console handshaking (in which case tty = NULL and we ignore
463  * incoming data).
464  */
465 static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip,
466                 struct tty_struct **hangup, struct hvsi_struct **handshake)
467 {
468         uint8_t *packet = hp->inbuf;
469         int chunklen;
470
471         *flip = NULL;
472         *hangup = NULL;
473         *handshake = NULL;
474
475         chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
476         if (chunklen == 0) {
477                 pr_debug("%s: 0-length read\n", __FUNCTION__);
478                 return 0;
479         }
480
481         pr_debug("%s: got %i bytes\n", __FUNCTION__, chunklen);
482         dbg_dump_hex(hp->inbuf_end, chunklen);
483
484         hp->inbuf_end += chunklen;
485
486         /* handle all completed packets */
487         while ((packet < hp->inbuf_end) && got_packet(hp, packet)) {
488                 struct hvsi_header *header = (struct hvsi_header *)packet;
489
490                 if (!is_header(packet)) {
491                         printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index);
492                         /* skip bytes until we find a header or run out of data */
493                         while ((packet < hp->inbuf_end) && (!is_header(packet)))
494                                 packet++;
495                         continue;
496                 }
497
498                 pr_debug("%s: handling %i-byte packet\n", __FUNCTION__,
499                                 len_packet(packet));
500                 dbg_dump_packet(packet);
501
502                 switch (header->type) {
503                         case VS_DATA_PACKET_HEADER:
504                                 if (!is_open(hp))
505                                         break;
506                                 if (hp->tty == NULL)
507                                         break; /* no tty buffer to put data in */
508                                 *flip = hvsi_recv_data(hp, packet);
509                                 break;
510                         case VS_CONTROL_PACKET_HEADER:
511                                 hvsi_recv_control(hp, packet, hangup, handshake);
512                                 break;
513                         case VS_QUERY_RESPONSE_PACKET_HEADER:
514                                 hvsi_recv_response(hp, packet);
515                                 break;
516                         case VS_QUERY_PACKET_HEADER:
517                                 hvsi_recv_query(hp, packet);
518                                 break;
519                         default:
520                                 printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
521                                                 hp->index, header->type);
522                                 dump_packet(packet);
523                                 break;
524                 }
525
526                 packet += len_packet(packet);
527
528                 if (*hangup || *handshake) {
529                         pr_debug("%s: hangup or handshake\n", __FUNCTION__);
530                         /*
531                          * we need to send the hangup now before receiving any more data.
532                          * If we get "data, hangup, data", we can't deliver the second
533                          * data before the hangup.
534                          */
535                         break;
536                 }
537         }
538
539         compact_inbuf(hp, packet);
540
541         return 1;
542 }
543
544 static void hvsi_send_overflow(struct hvsi_struct *hp)
545 {
546         pr_debug("%s: delivering %i bytes overflow\n", __FUNCTION__,
547                         hp->n_throttle);
548
549         hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);
550         hp->n_throttle = 0;
551 }
552
553 /*
554  * must get all pending data because we only get an irq on empty->non-empty
555  * transition
556  */
557 static irqreturn_t hvsi_interrupt(int irq, void *arg, struct pt_regs *regs)
558 {
559         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
560         struct tty_struct *flip;
561         struct tty_struct *hangup;
562         struct hvsi_struct *handshake;
563         unsigned long flags;
564         int again = 1;
565
566         pr_debug("%s\n", __FUNCTION__);
567
568         while (again) {
569                 spin_lock_irqsave(&hp->lock, flags);
570                 again = hvsi_load_chunk(hp, &flip, &hangup, &handshake);
571                 spin_unlock_irqrestore(&hp->lock, flags);
572
573                 /*
574                  * we have to call tty_flip_buffer_push() and tty_hangup() outside our
575                  * spinlock. But we also have to keep going until we've read all the
576                  * available data.
577                  */
578
579                 if (flip) {
580                         /* there was data put in the tty flip buffer */
581                         tty_flip_buffer_push(flip);
582                         flip = NULL;
583                 }
584
585                 if (hangup) {
586                         tty_hangup(hangup);
587                 }
588
589                 if (handshake) {
590                         pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
591                         schedule_work(&handshake->handshaker);
592                 }
593         }
594
595         spin_lock_irqsave(&hp->lock, flags);
596         if (hp->tty && hp->n_throttle
597                         && (!test_bit(TTY_THROTTLED, &hp->tty->flags))) {
598                 /* we weren't hung up and we weren't throttled, so we can deliver the
599                  * rest now */
600                 flip = hp->tty;
601                 hvsi_send_overflow(hp);
602         }
603         spin_unlock_irqrestore(&hp->lock, flags);
604
605         if (flip) {
606                 tty_flip_buffer_push(flip);
607         }
608
609         return IRQ_HANDLED;
610 }
611
612 /* for boot console, before the irq handler is running */
613 static int __init poll_for_state(struct hvsi_struct *hp, int state)
614 {
615         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
616
617         for (;;) {
618                 hvsi_interrupt(hp->virq, (void *)hp, NULL); /* get pending data */
619
620                 if (hp->state == state)
621                         return 0;
622
623                 mdelay(5);
624                 if (time_after(jiffies, end_jiffies))
625                         return -EIO;
626         }
627 }
628
629 /* wait for irq handler to change our state */
630 static int wait_for_state(struct hvsi_struct *hp, int state)
631 {
632         int ret = 0;
633
634         if (!wait_event_timeout(hp->stateq, (hp->state == state), HVSI_TIMEOUT))
635                 ret = -EIO;
636
637         return ret;
638 }
639
640 static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
641 {
642         struct hvsi_query packet __ALIGNED__;
643         int wrote;
644
645         packet.type = VS_QUERY_PACKET_HEADER;
646         packet.len = sizeof(struct hvsi_query);
647         packet.seqno = atomic_inc_return(&hp->seqno);
648         packet.verb = verb;
649
650         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
651         dbg_dump_hex((uint8_t*)&packet, packet.len);
652
653         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
654         if (wrote != packet.len) {
655                 printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
656                         wrote);
657                 return -EIO;
658         }
659
660         return 0;
661 }
662
663 static int hvsi_get_mctrl(struct hvsi_struct *hp)
664 {
665         int ret;
666
667         set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
668         hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
669
670         ret = hvsi_wait(hp, HVSI_OPEN);
671         if (ret < 0) {
672                 printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
673                 set_state(hp, HVSI_OPEN);
674                 return ret;
675         }
676
677         pr_debug("%s: mctrl 0x%x\n", __FUNCTION__, hp->mctrl);
678
679         return 0;
680 }
681
682 /* note that we can only set DTR */
683 static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
684 {
685         struct hvsi_control packet __ALIGNED__;
686         int wrote;
687
688         packet.type = VS_CONTROL_PACKET_HEADER,
689         packet.seqno = atomic_inc_return(&hp->seqno);
690         packet.len = sizeof(struct hvsi_control);
691         packet.verb = VSV_SET_MODEM_CTL;
692         packet.mask = HVSI_TSDTR;
693
694         if (mctrl & TIOCM_DTR)
695                 packet.word = HVSI_TSDTR;
696
697         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
698         dbg_dump_hex((uint8_t*)&packet, packet.len);
699
700         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
701         if (wrote != packet.len) {
702                 printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
703                 return -EIO;
704         }
705
706         return 0;
707 }
708
709 static void hvsi_drain_input(struct hvsi_struct *hp)
710 {
711         uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
712         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
713
714         while (time_before(end_jiffies, jiffies))
715                 if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
716                         break;
717 }
718
719 static int hvsi_handshake(struct hvsi_struct *hp)
720 {
721         int ret;
722
723         /*
724          * We could have a CLOSE or other data waiting for us before we even try
725          * to open; try to throw it all away so we don't get confused. (CLOSE
726          * is the first message sent up the pipe when the FSP comes online. We
727          * need to distinguish between "it came up a while ago and we're the first
728          * user" and "it was just reset before it saw our handshake packet".)
729          */
730         hvsi_drain_input(hp);
731
732         set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
733         ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
734         if (ret < 0) {
735                 printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
736                 return ret;
737         }
738
739         ret = hvsi_wait(hp, HVSI_OPEN);
740         if (ret < 0)
741                 return ret;
742
743         return 0;
744 }
745
746 static void hvsi_handshaker(void *arg)
747 {
748         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
749
750         if (hvsi_handshake(hp) >= 0)
751                 return;
752
753         printk(KERN_ERR "hvsi%i: re-handshaking failed\n", hp->index);
754         if (is_console(hp)) {
755                 /*
756                  * ttys will re-attempt the handshake via hvsi_open, but
757                  * the console will not.
758                  */
759                 printk(KERN_ERR "hvsi%i: lost console!\n", hp->index);
760         }
761 }
762
763 static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
764 {
765         struct hvsi_data packet __ALIGNED__;
766         int ret;
767
768         BUG_ON(count > HVSI_MAX_OUTGOING_DATA);
769
770         packet.type = VS_DATA_PACKET_HEADER;
771         packet.seqno = atomic_inc_return(&hp->seqno);
772         packet.len = count + sizeof(struct hvsi_header);
773         memcpy(&packet.data, buf, count);
774
775         ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
776         if (ret == packet.len) {
777                 /* return the number of chars written, not the packet length */
778                 return count;
779         }
780         return ret; /* return any errors */
781 }
782
783 static void hvsi_close_protocol(struct hvsi_struct *hp)
784 {
785         struct hvsi_control packet __ALIGNED__;
786
787         packet.type = VS_CONTROL_PACKET_HEADER;
788         packet.seqno = atomic_inc_return(&hp->seqno);
789         packet.len = 6;
790         packet.verb = VSV_CLOSE_PROTOCOL;
791
792         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
793         dbg_dump_hex((uint8_t*)&packet, packet.len);
794
795         hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
796 }
797
798 static int hvsi_open(struct tty_struct *tty, struct file *filp)
799 {
800         struct hvsi_struct *hp;
801         unsigned long flags;
802         int line = tty->index;
803         int ret;
804
805         pr_debug("%s\n", __FUNCTION__);
806
807         if (line < 0 || line >= hvsi_count)
808                 return -ENODEV;
809         hp = &hvsi_ports[line];
810
811         tty->driver_data = hp;
812         tty->low_latency = 1; /* avoid throttle/tty_flip_buffer_push race */
813
814         mb();
815         if (hp->state == HVSI_FSP_DIED)
816                 return -EIO;
817
818         spin_lock_irqsave(&hp->lock, flags);
819         hp->tty = tty;
820         hp->count++;
821         atomic_set(&hp->seqno, 0);
822         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
823         spin_unlock_irqrestore(&hp->lock, flags);
824
825         if (is_console(hp))
826                 return 0; /* this has already been handshaked as the console */
827
828         ret = hvsi_handshake(hp);
829         if (ret < 0) {
830                 printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
831                 return ret;
832         }
833
834         ret = hvsi_get_mctrl(hp);
835         if (ret < 0) {
836                 printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name);
837                 return ret;
838         }
839
840         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
841         if (ret < 0) {
842                 printk(KERN_ERR "%s: couldn't set DTR\n", tty->name);
843                 return ret;
844         }
845
846         return 0;
847 }
848
849 /* wait for hvsi_write_worker to empty hp->outbuf */
850 static void hvsi_flush_output(struct hvsi_struct *hp)
851 {
852         wait_event_timeout(hp->emptyq, (hp->n_outbuf <= 0), HVSI_TIMEOUT);
853
854         /* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */
855         cancel_delayed_work(&hp->writer);
856         flush_scheduled_work();
857
858         /*
859          * it's also possible that our timeout expired and hvsi_write_worker
860          * didn't manage to push outbuf. poof.
861          */
862         hp->n_outbuf = 0;
863 }
864
865 static void hvsi_close(struct tty_struct *tty, struct file *filp)
866 {
867         struct hvsi_struct *hp = tty->driver_data;
868         unsigned long flags;
869
870         pr_debug("%s\n", __FUNCTION__);
871
872         if (tty_hung_up_p(filp))
873                 return;
874
875         spin_lock_irqsave(&hp->lock, flags);
876
877         if (--hp->count == 0) {
878                 hp->tty = NULL;
879                 hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
880
881                 /* only close down connection if it is not the console */
882                 if (!is_console(hp)) {
883                         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */
884                         __set_state(hp, HVSI_CLOSED);
885                         /*
886                          * any data delivered to the tty layer after this will be
887                          * discarded (except for XON/XOFF)
888                          */
889                         tty->closing = 1;
890
891                         spin_unlock_irqrestore(&hp->lock, flags);
892
893                         /* let any existing irq handlers finish. no more will start. */
894                         synchronize_irq(hp->virq);
895
896                         /* hvsi_write_worker will re-schedule until outbuf is empty. */
897                         hvsi_flush_output(hp);
898
899                         /* tell FSP to stop sending data */
900                         hvsi_close_protocol(hp);
901
902                         /*
903                          * drain anything FSP is still in the middle of sending, and let
904                          * hvsi_handshake drain the rest on the next open.
905                          */
906                         hvsi_drain_input(hp);
907
908                         spin_lock_irqsave(&hp->lock, flags);
909                 }
910         } else if (hp->count < 0)
911                 printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n",
912                        hp - hvsi_ports, hp->count);
913
914         spin_unlock_irqrestore(&hp->lock, flags);
915 }
916
917 static void hvsi_hangup(struct tty_struct *tty)
918 {
919         struct hvsi_struct *hp = tty->driver_data;
920         unsigned long flags;
921
922         pr_debug("%s\n", __FUNCTION__);
923
924         spin_lock_irqsave(&hp->lock, flags);
925
926         hp->count = 0;
927         hp->n_outbuf = 0;
928         hp->tty = NULL;
929
930         spin_unlock_irqrestore(&hp->lock, flags);
931 }
932
933 /* called with hp->lock held */
934 static void hvsi_push(struct hvsi_struct *hp)
935 {
936         int n;
937
938         if (hp->n_outbuf <= 0)
939                 return;
940
941         n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf);
942         if (n > 0) {
943                 /* success */
944                 pr_debug("%s: wrote %i chars\n", __FUNCTION__, n);
945                 hp->n_outbuf = 0;
946         } else if (n == -EIO) {
947                 __set_state(hp, HVSI_FSP_DIED);
948                 printk(KERN_ERR "hvsi%i: service processor died\n", hp->index);
949         }
950 }
951
952 /* hvsi_write_worker will keep rescheduling itself until outbuf is empty */
953 static void hvsi_write_worker(void *arg)
954 {
955         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
956         unsigned long flags;
957 #ifdef DEBUG
958         static long start_j = 0;
959
960         if (start_j == 0)
961                 start_j = jiffies;
962 #endif /* DEBUG */
963
964         spin_lock_irqsave(&hp->lock, flags);
965
966         pr_debug("%s: %i chars in buffer\n", __FUNCTION__, hp->n_outbuf);
967
968         if (!is_open(hp)) {
969                 /*
970                  * We could have a non-open connection if the service processor died
971                  * while we were busily scheduling ourselves. In that case, it could
972                  * be minutes before the service processor comes back, so only try
973                  * again once a second.
974                  */
975                 schedule_delayed_work(&hp->writer, HZ);
976                 goto out;
977         }
978
979         hvsi_push(hp);
980         if (hp->n_outbuf > 0)
981                 schedule_delayed_work(&hp->writer, 10);
982         else {
983 #ifdef DEBUG
984                 pr_debug("%s: outbuf emptied after %li jiffies\n", __FUNCTION__,
985                                 jiffies - start_j);
986                 start_j = 0;
987 #endif /* DEBUG */
988                 wake_up_all(&hp->emptyq);
989                 if (test_bit(TTY_DO_WRITE_WAKEUP, &hp->tty->flags)
990                                 && hp->tty->ldisc.write_wakeup)
991                         hp->tty->ldisc.write_wakeup(hp->tty);
992                 wake_up_interruptible(&hp->tty->write_wait);
993         }
994
995 out:
996         spin_unlock_irqrestore(&hp->lock, flags);
997 }
998
999 static int hvsi_write_room(struct tty_struct *tty)
1000 {
1001         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1002
1003         return N_OUTBUF - hp->n_outbuf;
1004 }
1005
1006 static int hvsi_chars_in_buffer(struct tty_struct *tty)
1007 {
1008         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1009
1010         return hp->n_outbuf;
1011 }
1012
1013 static int hvsi_write(struct tty_struct *tty,
1014                      const unsigned char *buf, int count)
1015 {
1016         struct hvsi_struct *hp = tty->driver_data;
1017         const char *source = buf;
1018         unsigned long flags;
1019         int total = 0;
1020         int origcount = count;
1021
1022         spin_lock_irqsave(&hp->lock, flags);
1023
1024         pr_debug("%s: %i chars in buffer\n", __FUNCTION__, hp->n_outbuf);
1025
1026         if (!is_open(hp)) {
1027                 /* we're either closing or not yet open; don't accept data */
1028                 pr_debug("%s: not open\n", __FUNCTION__);
1029                 goto out;
1030         }
1031
1032         /*
1033          * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf
1034          * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls
1035          * will see there is no room in outbuf and return.
1036          */
1037         while ((count > 0) && (hvsi_write_room(hp->tty) > 0)) {
1038                 int chunksize = min(count, hvsi_write_room(hp->tty));
1039
1040                 BUG_ON(hp->n_outbuf < 0);
1041                 memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
1042                 hp->n_outbuf += chunksize;
1043
1044                 total += chunksize;
1045                 source += chunksize;
1046                 count -= chunksize;
1047                 hvsi_push(hp);
1048         }
1049
1050         if (hp->n_outbuf > 0) {
1051                 /*
1052                  * we weren't able to write it all to the hypervisor.
1053                  * schedule another push attempt.
1054                  */
1055                 schedule_delayed_work(&hp->writer, 10);
1056         }
1057
1058 out:
1059         spin_unlock_irqrestore(&hp->lock, flags);
1060
1061         if (total != origcount)
1062                 pr_debug("%s: wanted %i, only wrote %i\n", __FUNCTION__, origcount,
1063                         total);
1064
1065         return total;
1066 }
1067
1068 /*
1069  * I have never seen throttle or unthrottle called, so this little throttle
1070  * buffering scheme may or may not work.
1071  */
1072 static void hvsi_throttle(struct tty_struct *tty)
1073 {
1074         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1075
1076         pr_debug("%s\n", __FUNCTION__);
1077
1078         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE);
1079 }
1080
1081 static void hvsi_unthrottle(struct tty_struct *tty)
1082 {
1083         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1084         unsigned long flags;
1085         int shouldflip = 0;
1086
1087         pr_debug("%s\n", __FUNCTION__);
1088
1089         spin_lock_irqsave(&hp->lock, flags);
1090         if (hp->n_throttle) {
1091                 hvsi_send_overflow(hp);
1092                 shouldflip = 1;
1093         }
1094         spin_unlock_irqrestore(&hp->lock, flags);
1095
1096         if (shouldflip)
1097                 tty_flip_buffer_push(hp->tty);
1098
1099         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
1100 }
1101
1102 static int hvsi_tiocmget(struct tty_struct *tty, struct file *file)
1103 {
1104         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1105
1106         hvsi_get_mctrl(hp);
1107         return hp->mctrl;
1108 }
1109
1110 static int hvsi_tiocmset(struct tty_struct *tty, struct file *file,
1111                 unsigned int set, unsigned int clear)
1112 {
1113         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1114         unsigned long flags;
1115         uint16_t new_mctrl;
1116
1117         /* we can only alter DTR */
1118         clear &= TIOCM_DTR;
1119         set &= TIOCM_DTR;
1120
1121         spin_lock_irqsave(&hp->lock, flags);
1122
1123         new_mctrl = (hp->mctrl & ~clear) | set;
1124
1125         if (hp->mctrl != new_mctrl) {
1126                 hvsi_set_mctrl(hp, new_mctrl);
1127                 hp->mctrl = new_mctrl;
1128         }
1129         spin_unlock_irqrestore(&hp->lock, flags);
1130
1131         return 0;
1132 }
1133
1134
1135 static struct tty_operations hvsi_ops = {
1136         .open = hvsi_open,
1137         .close = hvsi_close,
1138         .write = hvsi_write,
1139         .hangup = hvsi_hangup,
1140         .write_room = hvsi_write_room,
1141         .chars_in_buffer = hvsi_chars_in_buffer,
1142         .throttle = hvsi_throttle,
1143         .unthrottle = hvsi_unthrottle,
1144         .tiocmget = hvsi_tiocmget,
1145         .tiocmset = hvsi_tiocmset,
1146 };
1147
1148 static int __init hvsi_init(void)
1149 {
1150         int i;
1151
1152         hvsi_driver = alloc_tty_driver(hvsi_count);
1153         if (!hvsi_driver)
1154                 return -ENOMEM;
1155
1156         hvsi_driver->owner = THIS_MODULE;
1157         hvsi_driver->driver_name = "hvsi";
1158         hvsi_driver->name = "hvsi";
1159         hvsi_driver->major = HVSI_MAJOR;
1160         hvsi_driver->minor_start = HVSI_MINOR;
1161         hvsi_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1162         hvsi_driver->init_termios = tty_std_termios;
1163         hvsi_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
1164         hvsi_driver->flags = TTY_DRIVER_REAL_RAW;
1165         tty_set_operations(hvsi_driver, &hvsi_ops);
1166
1167         for (i=0; i < hvsi_count; i++) {
1168                 struct hvsi_struct *hp = &hvsi_ports[i];
1169                 int ret = 1;
1170
1171                 ret = request_irq(hp->virq, hvsi_interrupt, IRQF_DISABLED, "hvsi", hp);
1172                 if (ret)
1173                         printk(KERN_ERR "HVSI: couldn't reserve irq 0x%x (error %i)\n",
1174                                 hp->virq, ret);
1175         }
1176         hvsi_wait = wait_for_state; /* irqs active now */
1177
1178         if (tty_register_driver(hvsi_driver))
1179                 panic("Couldn't register hvsi console driver\n");
1180
1181         printk(KERN_DEBUG "HVSI: registered %i devices\n", hvsi_count);
1182
1183         return 0;
1184 }
1185 device_initcall(hvsi_init);
1186
1187 /***** console (not tty) code: *****/
1188
1189 static void hvsi_console_print(struct console *console, const char *buf,
1190                 unsigned int count)
1191 {
1192         struct hvsi_struct *hp = &hvsi_ports[console->index];
1193         char c[HVSI_MAX_OUTGOING_DATA] __ALIGNED__;
1194         unsigned int i = 0, n = 0;
1195         int ret, donecr = 0;
1196
1197         mb();
1198         if (!is_open(hp))
1199                 return;
1200
1201         /*
1202          * ugh, we have to translate LF -> CRLF ourselves, in place.
1203          * copied from hvc_console.c:
1204          */
1205         while (count > 0 || i > 0) {
1206                 if (count > 0 && i < sizeof(c)) {
1207                         if (buf[n] == '\n' && !donecr) {
1208                                 c[i++] = '\r';
1209                                 donecr = 1;
1210                         } else {
1211                                 c[i++] = buf[n++];
1212                                 donecr = 0;
1213                                 --count;
1214                         }
1215                 } else {
1216                         ret = hvsi_put_chars(hp, c, i);
1217                         if (ret < 0)
1218                                 i = 0;
1219                         i -= ret;
1220                 }
1221         }
1222 }
1223
1224 static struct tty_driver *hvsi_console_device(struct console *console,
1225         int *index)
1226 {
1227         *index = console->index;
1228         return hvsi_driver;
1229 }
1230
1231 static int __init hvsi_console_setup(struct console *console, char *options)
1232 {
1233         struct hvsi_struct *hp = &hvsi_ports[console->index];
1234         int ret;
1235
1236         if (console->index < 0 || console->index >= hvsi_count)
1237                 return -1;
1238
1239         /* give the FSP a chance to change the baud rate when we re-open */
1240         hvsi_close_protocol(hp);
1241
1242         ret = hvsi_handshake(hp);
1243         if (ret < 0)
1244                 return ret;
1245
1246         ret = hvsi_get_mctrl(hp);
1247         if (ret < 0)
1248                 return ret;
1249
1250         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
1251         if (ret < 0)
1252                 return ret;
1253
1254         hp->flags |= HVSI_CONSOLE;
1255
1256         return 0;
1257 }
1258
1259 static struct console hvsi_con_driver = {
1260         .name           = "hvsi",
1261         .write          = hvsi_console_print,
1262         .device         = hvsi_console_device,
1263         .setup          = hvsi_console_setup,
1264         .flags          = CON_PRINTBUFFER,
1265         .index          = -1,
1266 };
1267
1268 static int __init hvsi_console_init(void)
1269 {
1270         struct device_node *vty;
1271
1272         hvsi_wait = poll_for_state; /* no irqs yet; must poll */
1273
1274         /* search device tree for vty nodes */
1275         for (vty = of_find_compatible_node(NULL, "serial", "hvterm-protocol");
1276                         vty != NULL;
1277                         vty = of_find_compatible_node(vty, "serial", "hvterm-protocol")) {
1278                 struct hvsi_struct *hp;
1279                 uint32_t *vtermno;
1280                 uint32_t *irq;
1281
1282                 vtermno = (uint32_t *)get_property(vty, "reg", NULL);
1283                 irq = (uint32_t *)get_property(vty, "interrupts", NULL);
1284                 if (!vtermno || !irq)
1285                         continue;
1286
1287                 if (hvsi_count >= MAX_NR_HVSI_CONSOLES) {
1288                         of_node_put(vty);
1289                         break;
1290                 }
1291
1292                 hp = &hvsi_ports[hvsi_count];
1293                 INIT_WORK(&hp->writer, hvsi_write_worker, hp);
1294                 INIT_WORK(&hp->handshaker, hvsi_handshaker, hp);
1295                 init_waitqueue_head(&hp->emptyq);
1296                 init_waitqueue_head(&hp->stateq);
1297                 spin_lock_init(&hp->lock);
1298                 hp->index = hvsi_count;
1299                 hp->inbuf_end = hp->inbuf;
1300                 hp->state = HVSI_CLOSED;
1301                 hp->vtermno = *vtermno;
1302                 hp->virq = irq_create_mapping(NULL, irq[0]);
1303                 if (hp->virq == NO_IRQ) {
1304                         printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
1305                                 __FUNCTION__, irq[0]);
1306                         continue;
1307                 }
1308
1309                 hvsi_count++;
1310         }
1311
1312         if (hvsi_count)
1313                 register_console(&hvsi_con_driver);
1314         return 0;
1315 }
1316 console_initcall(hvsi_console_init);