TTY: remove re-assignments to tty_driver members
[linux-2.6.git] / drivers / tty / hvc / 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/spinlock.h>
43 #include <linux/sysrq.h>
44 #include <linux/tty.h>
45 #include <linux/tty_flip.h>
46 #include <asm/hvcall.h>
47 #include <asm/hvconsole.h>
48 #include <asm/prom.h>
49 #include <asm/uaccess.h>
50 #include <asm/vio.h>
51 #include <asm/param.h>
52 #include <asm/hvsi.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 delayed_work 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         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 static inline int is_console(struct hvsi_struct *hp)
114 {
115         return hp->flags & HVSI_CONSOLE;
116 }
117
118 static inline int is_open(struct hvsi_struct *hp)
119 {
120         /* if we're waiting for an mctrl then we're already open */
121         return (hp->state == HVSI_OPEN)
122                         || (hp->state == HVSI_WAIT_FOR_MCTRL_RESPONSE);
123 }
124
125 static inline void print_state(struct hvsi_struct *hp)
126 {
127 #ifdef DEBUG
128         static const char *state_names[] = {
129                 "HVSI_CLOSED",
130                 "HVSI_WAIT_FOR_VER_RESPONSE",
131                 "HVSI_WAIT_FOR_VER_QUERY",
132                 "HVSI_OPEN",
133                 "HVSI_WAIT_FOR_MCTRL_RESPONSE",
134                 "HVSI_FSP_DIED",
135         };
136         const char *name = (hp->state < ARRAY_SIZE(state_names))
137                 ? state_names[hp->state] : "UNKNOWN";
138
139         pr_debug("hvsi%i: state = %s\n", hp->index, name);
140 #endif /* DEBUG */
141 }
142
143 static inline void __set_state(struct hvsi_struct *hp, int state)
144 {
145         hp->state = state;
146         print_state(hp);
147         wake_up_all(&hp->stateq);
148 }
149
150 static inline void set_state(struct hvsi_struct *hp, int state)
151 {
152         unsigned long flags;
153
154         spin_lock_irqsave(&hp->lock, flags);
155         __set_state(hp, state);
156         spin_unlock_irqrestore(&hp->lock, flags);
157 }
158
159 static inline int len_packet(const uint8_t *packet)
160 {
161         return (int)((struct hvsi_header *)packet)->len;
162 }
163
164 static inline int is_header(const uint8_t *packet)
165 {
166         struct hvsi_header *header = (struct hvsi_header *)packet;
167         return header->type >= VS_QUERY_RESPONSE_PACKET_HEADER;
168 }
169
170 static inline int got_packet(const struct hvsi_struct *hp, uint8_t *packet)
171 {
172         if (hp->inbuf_end < packet + sizeof(struct hvsi_header))
173                 return 0; /* don't even have the packet header */
174
175         if (hp->inbuf_end < (packet + len_packet(packet)))
176                 return 0; /* don't have the rest of the packet */
177
178         return 1;
179 }
180
181 /* shift remaining bytes in packetbuf down */
182 static void compact_inbuf(struct hvsi_struct *hp, uint8_t *read_to)
183 {
184         int remaining = (int)(hp->inbuf_end - read_to);
185
186         pr_debug("%s: %i chars remain\n", __func__, remaining);
187
188         if (read_to != hp->inbuf)
189                 memmove(hp->inbuf, read_to, remaining);
190
191         hp->inbuf_end = hp->inbuf + remaining;
192 }
193
194 #ifdef DEBUG
195 #define dbg_dump_packet(packet) dump_packet(packet)
196 #define dbg_dump_hex(data, len) dump_hex(data, len)
197 #else
198 #define dbg_dump_packet(packet) do { } while (0)
199 #define dbg_dump_hex(data, len) do { } while (0)
200 #endif
201
202 static void dump_hex(const uint8_t *data, int len)
203 {
204         int i;
205
206         printk("    ");
207         for (i=0; i < len; i++)
208                 printk("%.2x", data[i]);
209
210         printk("\n    ");
211         for (i=0; i < len; i++) {
212                 if (isprint(data[i]))
213                         printk("%c", data[i]);
214                 else
215                         printk(".");
216         }
217         printk("\n");
218 }
219
220 static void dump_packet(uint8_t *packet)
221 {
222         struct hvsi_header *header = (struct hvsi_header *)packet;
223
224         printk("type 0x%x, len %i, seqno %i:\n", header->type, header->len,
225                         header->seqno);
226
227         dump_hex(packet, header->len);
228 }
229
230 static int hvsi_read(struct hvsi_struct *hp, char *buf, int count)
231 {
232         unsigned long got;
233
234         got = hvc_get_chars(hp->vtermno, buf, count);
235
236         return got;
237 }
238
239 static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet,
240         struct tty_struct **to_hangup, struct hvsi_struct **to_handshake)
241 {
242         struct hvsi_control *header = (struct hvsi_control *)packet;
243
244         switch (header->verb) {
245                 case VSV_MODEM_CTL_UPDATE:
246                         if ((header->word & HVSI_TSCD) == 0) {
247                                 /* CD went away; no more connection */
248                                 pr_debug("hvsi%i: CD dropped\n", hp->index);
249                                 hp->mctrl &= TIOCM_CD;
250                                 /* If userland hasn't done an open(2) yet, hp->tty is NULL. */
251                                 if (hp->tty && !(hp->tty->flags & CLOCAL))
252                                         *to_hangup = hp->tty;
253                         }
254                         break;
255                 case VSV_CLOSE_PROTOCOL:
256                         pr_debug("hvsi%i: service processor came back\n", hp->index);
257                         if (hp->state != HVSI_CLOSED) {
258                                 *to_handshake = hp;
259                         }
260                         break;
261                 default:
262                         printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ",
263                                 hp->index);
264                         dump_packet(packet);
265                         break;
266         }
267 }
268
269 static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet)
270 {
271         struct hvsi_query_response *resp = (struct hvsi_query_response *)packet;
272
273         switch (hp->state) {
274                 case HVSI_WAIT_FOR_VER_RESPONSE:
275                         __set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
276                         break;
277                 case HVSI_WAIT_FOR_MCTRL_RESPONSE:
278                         hp->mctrl = 0;
279                         if (resp->u.mctrl_word & HVSI_TSDTR)
280                                 hp->mctrl |= TIOCM_DTR;
281                         if (resp->u.mctrl_word & HVSI_TSCD)
282                                 hp->mctrl |= TIOCM_CD;
283                         __set_state(hp, HVSI_OPEN);
284                         break;
285                 default:
286                         printk(KERN_ERR "hvsi%i: unexpected query response: ", hp->index);
287                         dump_packet(packet);
288                         break;
289         }
290 }
291
292 /* respond to service processor's version query */
293 static int hvsi_version_respond(struct hvsi_struct *hp, uint16_t query_seqno)
294 {
295         struct hvsi_query_response packet __ALIGNED__;
296         int wrote;
297
298         packet.hdr.type = VS_QUERY_RESPONSE_PACKET_HEADER;
299         packet.hdr.len = sizeof(struct hvsi_query_response);
300         packet.hdr.seqno = atomic_inc_return(&hp->seqno);
301         packet.verb = VSV_SEND_VERSION_NUMBER;
302         packet.u.version = HVSI_VERSION;
303         packet.query_seqno = query_seqno+1;
304
305         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
306         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
307
308         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
309         if (wrote != packet.hdr.len) {
310                 printk(KERN_ERR "hvsi%i: couldn't send query response!\n",
311                         hp->index);
312                 return -EIO;
313         }
314
315         return 0;
316 }
317
318 static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet)
319 {
320         struct hvsi_query *query = (struct hvsi_query *)packet;
321
322         switch (hp->state) {
323                 case HVSI_WAIT_FOR_VER_QUERY:
324                         hvsi_version_respond(hp, query->hdr.seqno);
325                         __set_state(hp, HVSI_OPEN);
326                         break;
327                 default:
328                         printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index);
329                         dump_packet(packet);
330                         break;
331         }
332 }
333
334 static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len)
335 {
336         int i;
337
338         for (i=0; i < len; i++) {
339                 char c = buf[i];
340 #ifdef CONFIG_MAGIC_SYSRQ
341                 if (c == '\0') {
342                         hp->sysrq = 1;
343                         continue;
344                 } else if (hp->sysrq) {
345                         handle_sysrq(c);
346                         hp->sysrq = 0;
347                         continue;
348                 }
349 #endif /* CONFIG_MAGIC_SYSRQ */
350                 tty_insert_flip_char(hp->tty, c, 0);
351         }
352 }
353
354 /*
355  * We could get 252 bytes of data at once here. But the tty layer only
356  * throttles us at TTY_THRESHOLD_THROTTLE (128) bytes, so we could overflow
357  * it. Accordingly we won't send more than 128 bytes at a time to the flip
358  * buffer, which will give the tty buffer a chance to throttle us. Should the
359  * value of TTY_THRESHOLD_THROTTLE change in n_tty.c, this code should be
360  * revisited.
361  */
362 #define TTY_THRESHOLD_THROTTLE 128
363 static struct tty_struct *hvsi_recv_data(struct hvsi_struct *hp,
364                 const uint8_t *packet)
365 {
366         const struct hvsi_header *header = (const struct hvsi_header *)packet;
367         const uint8_t *data = packet + sizeof(struct hvsi_header);
368         int datalen = header->len - sizeof(struct hvsi_header);
369         int overflow = datalen - TTY_THRESHOLD_THROTTLE;
370
371         pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data);
372
373         if (datalen == 0)
374                 return NULL;
375
376         if (overflow > 0) {
377                 pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __func__);
378                 datalen = TTY_THRESHOLD_THROTTLE;
379         }
380
381         hvsi_insert_chars(hp, data, datalen);
382
383         if (overflow > 0) {
384                 /*
385                  * we still have more data to deliver, so we need to save off the
386                  * overflow and send it later
387                  */
388                 pr_debug("%s: deferring overflow\n", __func__);
389                 memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow);
390                 hp->n_throttle = overflow;
391         }
392
393         return hp->tty;
394 }
395
396 /*
397  * Returns true/false indicating data successfully read from hypervisor.
398  * Used both to get packets for tty connections and to advance the state
399  * machine during console handshaking (in which case tty = NULL and we ignore
400  * incoming data).
401  */
402 static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip,
403                 struct tty_struct **hangup, struct hvsi_struct **handshake)
404 {
405         uint8_t *packet = hp->inbuf;
406         int chunklen;
407
408         *flip = NULL;
409         *hangup = NULL;
410         *handshake = NULL;
411
412         chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
413         if (chunklen == 0) {
414                 pr_debug("%s: 0-length read\n", __func__);
415                 return 0;
416         }
417
418         pr_debug("%s: got %i bytes\n", __func__, chunklen);
419         dbg_dump_hex(hp->inbuf_end, chunklen);
420
421         hp->inbuf_end += chunklen;
422
423         /* handle all completed packets */
424         while ((packet < hp->inbuf_end) && got_packet(hp, packet)) {
425                 struct hvsi_header *header = (struct hvsi_header *)packet;
426
427                 if (!is_header(packet)) {
428                         printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index);
429                         /* skip bytes until we find a header or run out of data */
430                         while ((packet < hp->inbuf_end) && (!is_header(packet)))
431                                 packet++;
432                         continue;
433                 }
434
435                 pr_debug("%s: handling %i-byte packet\n", __func__,
436                                 len_packet(packet));
437                 dbg_dump_packet(packet);
438
439                 switch (header->type) {
440                         case VS_DATA_PACKET_HEADER:
441                                 if (!is_open(hp))
442                                         break;
443                                 if (hp->tty == NULL)
444                                         break; /* no tty buffer to put data in */
445                                 *flip = hvsi_recv_data(hp, packet);
446                                 break;
447                         case VS_CONTROL_PACKET_HEADER:
448                                 hvsi_recv_control(hp, packet, hangup, handshake);
449                                 break;
450                         case VS_QUERY_RESPONSE_PACKET_HEADER:
451                                 hvsi_recv_response(hp, packet);
452                                 break;
453                         case VS_QUERY_PACKET_HEADER:
454                                 hvsi_recv_query(hp, packet);
455                                 break;
456                         default:
457                                 printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
458                                                 hp->index, header->type);
459                                 dump_packet(packet);
460                                 break;
461                 }
462
463                 packet += len_packet(packet);
464
465                 if (*hangup || *handshake) {
466                         pr_debug("%s: hangup or handshake\n", __func__);
467                         /*
468                          * we need to send the hangup now before receiving any more data.
469                          * If we get "data, hangup, data", we can't deliver the second
470                          * data before the hangup.
471                          */
472                         break;
473                 }
474         }
475
476         compact_inbuf(hp, packet);
477
478         return 1;
479 }
480
481 static void hvsi_send_overflow(struct hvsi_struct *hp)
482 {
483         pr_debug("%s: delivering %i bytes overflow\n", __func__,
484                         hp->n_throttle);
485
486         hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);
487         hp->n_throttle = 0;
488 }
489
490 /*
491  * must get all pending data because we only get an irq on empty->non-empty
492  * transition
493  */
494 static irqreturn_t hvsi_interrupt(int irq, void *arg)
495 {
496         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
497         struct tty_struct *flip;
498         struct tty_struct *hangup;
499         struct hvsi_struct *handshake;
500         unsigned long flags;
501         int again = 1;
502
503         pr_debug("%s\n", __func__);
504
505         while (again) {
506                 spin_lock_irqsave(&hp->lock, flags);
507                 again = hvsi_load_chunk(hp, &flip, &hangup, &handshake);
508                 spin_unlock_irqrestore(&hp->lock, flags);
509
510                 /*
511                  * we have to call tty_flip_buffer_push() and tty_hangup() outside our
512                  * spinlock. But we also have to keep going until we've read all the
513                  * available data.
514                  */
515
516                 if (flip) {
517                         /* there was data put in the tty flip buffer */
518                         tty_flip_buffer_push(flip);
519                         flip = NULL;
520                 }
521
522                 if (hangup) {
523                         tty_hangup(hangup);
524                 }
525
526                 if (handshake) {
527                         pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
528                         schedule_work(&handshake->handshaker);
529                 }
530         }
531
532         spin_lock_irqsave(&hp->lock, flags);
533         if (hp->tty && hp->n_throttle
534                         && (!test_bit(TTY_THROTTLED, &hp->tty->flags))) {
535                 /* we weren't hung up and we weren't throttled, so we can deliver the
536                  * rest now */
537                 flip = hp->tty;
538                 hvsi_send_overflow(hp);
539         }
540         spin_unlock_irqrestore(&hp->lock, flags);
541
542         if (flip) {
543                 tty_flip_buffer_push(flip);
544         }
545
546         return IRQ_HANDLED;
547 }
548
549 /* for boot console, before the irq handler is running */
550 static int __init poll_for_state(struct hvsi_struct *hp, int state)
551 {
552         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
553
554         for (;;) {
555                 hvsi_interrupt(hp->virq, (void *)hp); /* get pending data */
556
557                 if (hp->state == state)
558                         return 0;
559
560                 mdelay(5);
561                 if (time_after(jiffies, end_jiffies))
562                         return -EIO;
563         }
564 }
565
566 /* wait for irq handler to change our state */
567 static int wait_for_state(struct hvsi_struct *hp, int state)
568 {
569         int ret = 0;
570
571         if (!wait_event_timeout(hp->stateq, (hp->state == state), HVSI_TIMEOUT))
572                 ret = -EIO;
573
574         return ret;
575 }
576
577 static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
578 {
579         struct hvsi_query packet __ALIGNED__;
580         int wrote;
581
582         packet.hdr.type = VS_QUERY_PACKET_HEADER;
583         packet.hdr.len = sizeof(struct hvsi_query);
584         packet.hdr.seqno = atomic_inc_return(&hp->seqno);
585         packet.verb = verb;
586
587         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
588         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
589
590         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
591         if (wrote != packet.hdr.len) {
592                 printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
593                         wrote);
594                 return -EIO;
595         }
596
597         return 0;
598 }
599
600 static int hvsi_get_mctrl(struct hvsi_struct *hp)
601 {
602         int ret;
603
604         set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
605         hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
606
607         ret = hvsi_wait(hp, HVSI_OPEN);
608         if (ret < 0) {
609                 printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
610                 set_state(hp, HVSI_OPEN);
611                 return ret;
612         }
613
614         pr_debug("%s: mctrl 0x%x\n", __func__, hp->mctrl);
615
616         return 0;
617 }
618
619 /* note that we can only set DTR */
620 static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
621 {
622         struct hvsi_control packet __ALIGNED__;
623         int wrote;
624
625         packet.hdr.type = VS_CONTROL_PACKET_HEADER,
626         packet.hdr.seqno = atomic_inc_return(&hp->seqno);
627         packet.hdr.len = sizeof(struct hvsi_control);
628         packet.verb = VSV_SET_MODEM_CTL;
629         packet.mask = HVSI_TSDTR;
630
631         if (mctrl & TIOCM_DTR)
632                 packet.word = HVSI_TSDTR;
633
634         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
635         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
636
637         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
638         if (wrote != packet.hdr.len) {
639                 printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
640                 return -EIO;
641         }
642
643         return 0;
644 }
645
646 static void hvsi_drain_input(struct hvsi_struct *hp)
647 {
648         uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
649         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
650
651         while (time_before(end_jiffies, jiffies))
652                 if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
653                         break;
654 }
655
656 static int hvsi_handshake(struct hvsi_struct *hp)
657 {
658         int ret;
659
660         /*
661          * We could have a CLOSE or other data waiting for us before we even try
662          * to open; try to throw it all away so we don't get confused. (CLOSE
663          * is the first message sent up the pipe when the FSP comes online. We
664          * need to distinguish between "it came up a while ago and we're the first
665          * user" and "it was just reset before it saw our handshake packet".)
666          */
667         hvsi_drain_input(hp);
668
669         set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
670         ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
671         if (ret < 0) {
672                 printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
673                 return ret;
674         }
675
676         ret = hvsi_wait(hp, HVSI_OPEN);
677         if (ret < 0)
678                 return ret;
679
680         return 0;
681 }
682
683 static void hvsi_handshaker(struct work_struct *work)
684 {
685         struct hvsi_struct *hp =
686                 container_of(work, struct hvsi_struct, handshaker);
687
688         if (hvsi_handshake(hp) >= 0)
689                 return;
690
691         printk(KERN_ERR "hvsi%i: re-handshaking failed\n", hp->index);
692         if (is_console(hp)) {
693                 /*
694                  * ttys will re-attempt the handshake via hvsi_open, but
695                  * the console will not.
696                  */
697                 printk(KERN_ERR "hvsi%i: lost console!\n", hp->index);
698         }
699 }
700
701 static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
702 {
703         struct hvsi_data packet __ALIGNED__;
704         int ret;
705
706         BUG_ON(count > HVSI_MAX_OUTGOING_DATA);
707
708         packet.hdr.type = VS_DATA_PACKET_HEADER;
709         packet.hdr.seqno = atomic_inc_return(&hp->seqno);
710         packet.hdr.len = count + sizeof(struct hvsi_header);
711         memcpy(&packet.data, buf, count);
712
713         ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
714         if (ret == packet.hdr.len) {
715                 /* return the number of chars written, not the packet length */
716                 return count;
717         }
718         return ret; /* return any errors */
719 }
720
721 static void hvsi_close_protocol(struct hvsi_struct *hp)
722 {
723         struct hvsi_control packet __ALIGNED__;
724
725         packet.hdr.type = VS_CONTROL_PACKET_HEADER;
726         packet.hdr.seqno = atomic_inc_return(&hp->seqno);
727         packet.hdr.len = 6;
728         packet.verb = VSV_CLOSE_PROTOCOL;
729
730         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
731         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
732
733         hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
734 }
735
736 static int hvsi_open(struct tty_struct *tty, struct file *filp)
737 {
738         struct hvsi_struct *hp;
739         unsigned long flags;
740         int line = tty->index;
741         int ret;
742
743         pr_debug("%s\n", __func__);
744
745         if (line < 0 || line >= hvsi_count)
746                 return -ENODEV;
747         hp = &hvsi_ports[line];
748
749         tty->driver_data = hp;
750
751         mb();
752         if (hp->state == HVSI_FSP_DIED)
753                 return -EIO;
754
755         spin_lock_irqsave(&hp->lock, flags);
756         hp->tty = tty;
757         hp->count++;
758         atomic_set(&hp->seqno, 0);
759         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
760         spin_unlock_irqrestore(&hp->lock, flags);
761
762         if (is_console(hp))
763                 return 0; /* this has already been handshaked as the console */
764
765         ret = hvsi_handshake(hp);
766         if (ret < 0) {
767                 printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
768                 return ret;
769         }
770
771         ret = hvsi_get_mctrl(hp);
772         if (ret < 0) {
773                 printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name);
774                 return ret;
775         }
776
777         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
778         if (ret < 0) {
779                 printk(KERN_ERR "%s: couldn't set DTR\n", tty->name);
780                 return ret;
781         }
782
783         return 0;
784 }
785
786 /* wait for hvsi_write_worker to empty hp->outbuf */
787 static void hvsi_flush_output(struct hvsi_struct *hp)
788 {
789         wait_event_timeout(hp->emptyq, (hp->n_outbuf <= 0), HVSI_TIMEOUT);
790
791         /* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */
792         cancel_delayed_work_sync(&hp->writer);
793         flush_work_sync(&hp->handshaker);
794
795         /*
796          * it's also possible that our timeout expired and hvsi_write_worker
797          * didn't manage to push outbuf. poof.
798          */
799         hp->n_outbuf = 0;
800 }
801
802 static void hvsi_close(struct tty_struct *tty, struct file *filp)
803 {
804         struct hvsi_struct *hp = tty->driver_data;
805         unsigned long flags;
806
807         pr_debug("%s\n", __func__);
808
809         if (tty_hung_up_p(filp))
810                 return;
811
812         spin_lock_irqsave(&hp->lock, flags);
813
814         if (--hp->count == 0) {
815                 hp->tty = NULL;
816                 hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
817
818                 /* only close down connection if it is not the console */
819                 if (!is_console(hp)) {
820                         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */
821                         __set_state(hp, HVSI_CLOSED);
822                         /*
823                          * any data delivered to the tty layer after this will be
824                          * discarded (except for XON/XOFF)
825                          */
826                         tty->closing = 1;
827
828                         spin_unlock_irqrestore(&hp->lock, flags);
829
830                         /* let any existing irq handlers finish. no more will start. */
831                         synchronize_irq(hp->virq);
832
833                         /* hvsi_write_worker will re-schedule until outbuf is empty. */
834                         hvsi_flush_output(hp);
835
836                         /* tell FSP to stop sending data */
837                         hvsi_close_protocol(hp);
838
839                         /*
840                          * drain anything FSP is still in the middle of sending, and let
841                          * hvsi_handshake drain the rest on the next open.
842                          */
843                         hvsi_drain_input(hp);
844
845                         spin_lock_irqsave(&hp->lock, flags);
846                 }
847         } else if (hp->count < 0)
848                 printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n",
849                        hp - hvsi_ports, hp->count);
850
851         spin_unlock_irqrestore(&hp->lock, flags);
852 }
853
854 static void hvsi_hangup(struct tty_struct *tty)
855 {
856         struct hvsi_struct *hp = tty->driver_data;
857         unsigned long flags;
858
859         pr_debug("%s\n", __func__);
860
861         spin_lock_irqsave(&hp->lock, flags);
862
863         hp->count = 0;
864         hp->n_outbuf = 0;
865         hp->tty = NULL;
866
867         spin_unlock_irqrestore(&hp->lock, flags);
868 }
869
870 /* called with hp->lock held */
871 static void hvsi_push(struct hvsi_struct *hp)
872 {
873         int n;
874
875         if (hp->n_outbuf <= 0)
876                 return;
877
878         n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf);
879         if (n > 0) {
880                 /* success */
881                 pr_debug("%s: wrote %i chars\n", __func__, n);
882                 hp->n_outbuf = 0;
883         } else if (n == -EIO) {
884                 __set_state(hp, HVSI_FSP_DIED);
885                 printk(KERN_ERR "hvsi%i: service processor died\n", hp->index);
886         }
887 }
888
889 /* hvsi_write_worker will keep rescheduling itself until outbuf is empty */
890 static void hvsi_write_worker(struct work_struct *work)
891 {
892         struct hvsi_struct *hp =
893                 container_of(work, struct hvsi_struct, writer.work);
894         unsigned long flags;
895 #ifdef DEBUG
896         static long start_j = 0;
897
898         if (start_j == 0)
899                 start_j = jiffies;
900 #endif /* DEBUG */
901
902         spin_lock_irqsave(&hp->lock, flags);
903
904         pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
905
906         if (!is_open(hp)) {
907                 /*
908                  * We could have a non-open connection if the service processor died
909                  * while we were busily scheduling ourselves. In that case, it could
910                  * be minutes before the service processor comes back, so only try
911                  * again once a second.
912                  */
913                 schedule_delayed_work(&hp->writer, HZ);
914                 goto out;
915         }
916
917         hvsi_push(hp);
918         if (hp->n_outbuf > 0)
919                 schedule_delayed_work(&hp->writer, 10);
920         else {
921 #ifdef DEBUG
922                 pr_debug("%s: outbuf emptied after %li jiffies\n", __func__,
923                                 jiffies - start_j);
924                 start_j = 0;
925 #endif /* DEBUG */
926                 wake_up_all(&hp->emptyq);
927                 tty_wakeup(hp->tty);
928         }
929
930 out:
931         spin_unlock_irqrestore(&hp->lock, flags);
932 }
933
934 static int hvsi_write_room(struct tty_struct *tty)
935 {
936         struct hvsi_struct *hp = tty->driver_data;
937
938         return N_OUTBUF - hp->n_outbuf;
939 }
940
941 static int hvsi_chars_in_buffer(struct tty_struct *tty)
942 {
943         struct hvsi_struct *hp = tty->driver_data;
944
945         return hp->n_outbuf;
946 }
947
948 static int hvsi_write(struct tty_struct *tty,
949                      const unsigned char *buf, int count)
950 {
951         struct hvsi_struct *hp = tty->driver_data;
952         const char *source = buf;
953         unsigned long flags;
954         int total = 0;
955         int origcount = count;
956
957         spin_lock_irqsave(&hp->lock, flags);
958
959         pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
960
961         if (!is_open(hp)) {
962                 /* we're either closing or not yet open; don't accept data */
963                 pr_debug("%s: not open\n", __func__);
964                 goto out;
965         }
966
967         /*
968          * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf
969          * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls
970          * will see there is no room in outbuf and return.
971          */
972         while ((count > 0) && (hvsi_write_room(hp->tty) > 0)) {
973                 int chunksize = min(count, hvsi_write_room(hp->tty));
974
975                 BUG_ON(hp->n_outbuf < 0);
976                 memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
977                 hp->n_outbuf += chunksize;
978
979                 total += chunksize;
980                 source += chunksize;
981                 count -= chunksize;
982                 hvsi_push(hp);
983         }
984
985         if (hp->n_outbuf > 0) {
986                 /*
987                  * we weren't able to write it all to the hypervisor.
988                  * schedule another push attempt.
989                  */
990                 schedule_delayed_work(&hp->writer, 10);
991         }
992
993 out:
994         spin_unlock_irqrestore(&hp->lock, flags);
995
996         if (total != origcount)
997                 pr_debug("%s: wanted %i, only wrote %i\n", __func__, origcount,
998                         total);
999
1000         return total;
1001 }
1002
1003 /*
1004  * I have never seen throttle or unthrottle called, so this little throttle
1005  * buffering scheme may or may not work.
1006  */
1007 static void hvsi_throttle(struct tty_struct *tty)
1008 {
1009         struct hvsi_struct *hp = tty->driver_data;
1010
1011         pr_debug("%s\n", __func__);
1012
1013         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE);
1014 }
1015
1016 static void hvsi_unthrottle(struct tty_struct *tty)
1017 {
1018         struct hvsi_struct *hp = tty->driver_data;
1019         unsigned long flags;
1020         int shouldflip = 0;
1021
1022         pr_debug("%s\n", __func__);
1023
1024         spin_lock_irqsave(&hp->lock, flags);
1025         if (hp->n_throttle) {
1026                 hvsi_send_overflow(hp);
1027                 shouldflip = 1;
1028         }
1029         spin_unlock_irqrestore(&hp->lock, flags);
1030
1031         if (shouldflip)
1032                 tty_flip_buffer_push(hp->tty);
1033
1034         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
1035 }
1036
1037 static int hvsi_tiocmget(struct tty_struct *tty)
1038 {
1039         struct hvsi_struct *hp = tty->driver_data;
1040
1041         hvsi_get_mctrl(hp);
1042         return hp->mctrl;
1043 }
1044
1045 static int hvsi_tiocmset(struct tty_struct *tty,
1046                                 unsigned int set, unsigned int clear)
1047 {
1048         struct hvsi_struct *hp = tty->driver_data;
1049         unsigned long flags;
1050         uint16_t new_mctrl;
1051
1052         /* we can only alter DTR */
1053         clear &= TIOCM_DTR;
1054         set &= TIOCM_DTR;
1055
1056         spin_lock_irqsave(&hp->lock, flags);
1057
1058         new_mctrl = (hp->mctrl & ~clear) | set;
1059
1060         if (hp->mctrl != new_mctrl) {
1061                 hvsi_set_mctrl(hp, new_mctrl);
1062                 hp->mctrl = new_mctrl;
1063         }
1064         spin_unlock_irqrestore(&hp->lock, flags);
1065
1066         return 0;
1067 }
1068
1069
1070 static const struct tty_operations hvsi_ops = {
1071         .open = hvsi_open,
1072         .close = hvsi_close,
1073         .write = hvsi_write,
1074         .hangup = hvsi_hangup,
1075         .write_room = hvsi_write_room,
1076         .chars_in_buffer = hvsi_chars_in_buffer,
1077         .throttle = hvsi_throttle,
1078         .unthrottle = hvsi_unthrottle,
1079         .tiocmget = hvsi_tiocmget,
1080         .tiocmset = hvsi_tiocmset,
1081 };
1082
1083 static int __init hvsi_init(void)
1084 {
1085         int i;
1086
1087         hvsi_driver = alloc_tty_driver(hvsi_count);
1088         if (!hvsi_driver)
1089                 return -ENOMEM;
1090
1091         hvsi_driver->driver_name = "hvsi";
1092         hvsi_driver->name = "hvsi";
1093         hvsi_driver->major = HVSI_MAJOR;
1094         hvsi_driver->minor_start = HVSI_MINOR;
1095         hvsi_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1096         hvsi_driver->init_termios = tty_std_termios;
1097         hvsi_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
1098         hvsi_driver->init_termios.c_ispeed = 9600;
1099         hvsi_driver->init_termios.c_ospeed = 9600;
1100         hvsi_driver->flags = TTY_DRIVER_REAL_RAW;
1101         tty_set_operations(hvsi_driver, &hvsi_ops);
1102
1103         for (i=0; i < hvsi_count; i++) {
1104                 struct hvsi_struct *hp = &hvsi_ports[i];
1105                 int ret = 1;
1106
1107                 ret = request_irq(hp->virq, hvsi_interrupt, 0, "hvsi", hp);
1108                 if (ret)
1109                         printk(KERN_ERR "HVSI: couldn't reserve irq 0x%x (error %i)\n",
1110                                 hp->virq, ret);
1111         }
1112         hvsi_wait = wait_for_state; /* irqs active now */
1113
1114         if (tty_register_driver(hvsi_driver))
1115                 panic("Couldn't register hvsi console driver\n");
1116
1117         printk(KERN_DEBUG "HVSI: registered %i devices\n", hvsi_count);
1118
1119         return 0;
1120 }
1121 device_initcall(hvsi_init);
1122
1123 /***** console (not tty) code: *****/
1124
1125 static void hvsi_console_print(struct console *console, const char *buf,
1126                 unsigned int count)
1127 {
1128         struct hvsi_struct *hp = &hvsi_ports[console->index];
1129         char c[HVSI_MAX_OUTGOING_DATA] __ALIGNED__;
1130         unsigned int i = 0, n = 0;
1131         int ret, donecr = 0;
1132
1133         mb();
1134         if (!is_open(hp))
1135                 return;
1136
1137         /*
1138          * ugh, we have to translate LF -> CRLF ourselves, in place.
1139          * copied from hvc_console.c:
1140          */
1141         while (count > 0 || i > 0) {
1142                 if (count > 0 && i < sizeof(c)) {
1143                         if (buf[n] == '\n' && !donecr) {
1144                                 c[i++] = '\r';
1145                                 donecr = 1;
1146                         } else {
1147                                 c[i++] = buf[n++];
1148                                 donecr = 0;
1149                                 --count;
1150                         }
1151                 } else {
1152                         ret = hvsi_put_chars(hp, c, i);
1153                         if (ret < 0)
1154                                 i = 0;
1155                         i -= ret;
1156                 }
1157         }
1158 }
1159
1160 static struct tty_driver *hvsi_console_device(struct console *console,
1161         int *index)
1162 {
1163         *index = console->index;
1164         return hvsi_driver;
1165 }
1166
1167 static int __init hvsi_console_setup(struct console *console, char *options)
1168 {
1169         struct hvsi_struct *hp;
1170         int ret;
1171
1172         if (console->index < 0 || console->index >= hvsi_count)
1173                 return -1;
1174         hp = &hvsi_ports[console->index];
1175
1176         /* give the FSP a chance to change the baud rate when we re-open */
1177         hvsi_close_protocol(hp);
1178
1179         ret = hvsi_handshake(hp);
1180         if (ret < 0)
1181                 return ret;
1182
1183         ret = hvsi_get_mctrl(hp);
1184         if (ret < 0)
1185                 return ret;
1186
1187         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
1188         if (ret < 0)
1189                 return ret;
1190
1191         hp->flags |= HVSI_CONSOLE;
1192
1193         return 0;
1194 }
1195
1196 static struct console hvsi_console = {
1197         .name           = "hvsi",
1198         .write          = hvsi_console_print,
1199         .device         = hvsi_console_device,
1200         .setup          = hvsi_console_setup,
1201         .flags          = CON_PRINTBUFFER,
1202         .index          = -1,
1203 };
1204
1205 static int __init hvsi_console_init(void)
1206 {
1207         struct device_node *vty;
1208
1209         hvsi_wait = poll_for_state; /* no irqs yet; must poll */
1210
1211         /* search device tree for vty nodes */
1212         for (vty = of_find_compatible_node(NULL, "serial", "hvterm-protocol");
1213                         vty != NULL;
1214                         vty = of_find_compatible_node(vty, "serial", "hvterm-protocol")) {
1215                 struct hvsi_struct *hp;
1216                 const uint32_t *vtermno, *irq;
1217
1218                 vtermno = of_get_property(vty, "reg", NULL);
1219                 irq = of_get_property(vty, "interrupts", NULL);
1220                 if (!vtermno || !irq)
1221                         continue;
1222
1223                 if (hvsi_count >= MAX_NR_HVSI_CONSOLES) {
1224                         of_node_put(vty);
1225                         break;
1226                 }
1227
1228                 hp = &hvsi_ports[hvsi_count];
1229                 INIT_DELAYED_WORK(&hp->writer, hvsi_write_worker);
1230                 INIT_WORK(&hp->handshaker, hvsi_handshaker);
1231                 init_waitqueue_head(&hp->emptyq);
1232                 init_waitqueue_head(&hp->stateq);
1233                 spin_lock_init(&hp->lock);
1234                 hp->index = hvsi_count;
1235                 hp->inbuf_end = hp->inbuf;
1236                 hp->state = HVSI_CLOSED;
1237                 hp->vtermno = *vtermno;
1238                 hp->virq = irq_create_mapping(NULL, irq[0]);
1239                 if (hp->virq == 0) {
1240                         printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
1241                                 __func__, irq[0]);
1242                         continue;
1243                 }
1244
1245                 hvsi_count++;
1246         }
1247
1248         if (hvsi_count)
1249                 register_console(&hvsi_console);
1250         return 0;
1251 }
1252 console_initcall(hvsi_console_init);