2cf63e7305a3b067896df8a4c7bd35d77d1980c0
[linux-3.10.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 userland hasn't done an open(2) yet, hp->tty is NULL. */
315                                 if (hp->tty && !(hp->tty->flags & CLOCAL))
316                                         *to_hangup = hp->tty;
317                         }
318                         break;
319                 case VSV_CLOSE_PROTOCOL:
320                         pr_debug("hvsi%i: service processor came back\n", hp->index);
321                         if (hp->state != HVSI_CLOSED) {
322                                 *to_handshake = hp;
323                         }
324                         break;
325                 default:
326                         printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ",
327                                 hp->index);
328                         dump_packet(packet);
329                         break;
330         }
331 }
332
333 static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet)
334 {
335         struct hvsi_query_response *resp = (struct hvsi_query_response *)packet;
336
337         switch (hp->state) {
338                 case HVSI_WAIT_FOR_VER_RESPONSE:
339                         __set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
340                         break;
341                 case HVSI_WAIT_FOR_MCTRL_RESPONSE:
342                         hp->mctrl = 0;
343                         if (resp->u.mctrl_word & HVSI_TSDTR)
344                                 hp->mctrl |= TIOCM_DTR;
345                         if (resp->u.mctrl_word & HVSI_TSCD)
346                                 hp->mctrl |= TIOCM_CD;
347                         __set_state(hp, HVSI_OPEN);
348                         break;
349                 default:
350                         printk(KERN_ERR "hvsi%i: unexpected query response: ", hp->index);
351                         dump_packet(packet);
352                         break;
353         }
354 }
355
356 /* respond to service processor's version query */
357 static int hvsi_version_respond(struct hvsi_struct *hp, uint16_t query_seqno)
358 {
359         struct hvsi_query_response packet __ALIGNED__;
360         int wrote;
361
362         packet.type = VS_QUERY_RESPONSE_PACKET_HEADER;
363         packet.len = sizeof(struct hvsi_query_response);
364         packet.seqno = atomic_inc_return(&hp->seqno);
365         packet.verb = VSV_SEND_VERSION_NUMBER;
366         packet.u.version = HVSI_VERSION;
367         packet.query_seqno = query_seqno+1;
368
369         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
370         dbg_dump_hex((uint8_t*)&packet, packet.len);
371
372         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
373         if (wrote != packet.len) {
374                 printk(KERN_ERR "hvsi%i: couldn't send query response!\n",
375                         hp->index);
376                 return -EIO;
377         }
378
379         return 0;
380 }
381
382 static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet)
383 {
384         struct hvsi_query *query = (struct hvsi_query *)packet;
385
386         switch (hp->state) {
387                 case HVSI_WAIT_FOR_VER_QUERY:
388                         hvsi_version_respond(hp, query->seqno);
389                         __set_state(hp, HVSI_OPEN);
390                         break;
391                 default:
392                         printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index);
393                         dump_packet(packet);
394                         break;
395         }
396 }
397
398 static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len)
399 {
400         int i;
401
402         for (i=0; i < len; i++) {
403                 char c = buf[i];
404 #ifdef CONFIG_MAGIC_SYSRQ
405                 if (c == '\0') {
406                         hp->sysrq = 1;
407                         continue;
408                 } else if (hp->sysrq) {
409                         handle_sysrq(c, hp->tty);
410                         hp->sysrq = 0;
411                         continue;
412                 }
413 #endif /* CONFIG_MAGIC_SYSRQ */
414                 tty_insert_flip_char(hp->tty, c, 0);
415         }
416 }
417
418 /*
419  * We could get 252 bytes of data at once here. But the tty layer only
420  * throttles us at TTY_THRESHOLD_THROTTLE (128) bytes, so we could overflow
421  * it. Accordingly we won't send more than 128 bytes at a time to the flip
422  * buffer, which will give the tty buffer a chance to throttle us. Should the
423  * value of TTY_THRESHOLD_THROTTLE change in n_tty.c, this code should be
424  * revisited.
425  */
426 #define TTY_THRESHOLD_THROTTLE 128
427 static struct tty_struct *hvsi_recv_data(struct hvsi_struct *hp,
428                 const uint8_t *packet)
429 {
430         const struct hvsi_header *header = (const struct hvsi_header *)packet;
431         const uint8_t *data = packet + sizeof(struct hvsi_header);
432         int datalen = header->len - sizeof(struct hvsi_header);
433         int overflow = datalen - TTY_THRESHOLD_THROTTLE;
434
435         pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data);
436
437         if (datalen == 0)
438                 return NULL;
439
440         if (overflow > 0) {
441                 pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __FUNCTION__);
442                 datalen = TTY_THRESHOLD_THROTTLE;
443         }
444
445         hvsi_insert_chars(hp, data, datalen);
446
447         if (overflow > 0) {
448                 /*
449                  * we still have more data to deliver, so we need to save off the
450                  * overflow and send it later
451                  */
452                 pr_debug("%s: deferring overflow\n", __FUNCTION__);
453                 memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow);
454                 hp->n_throttle = overflow;
455         }
456
457         return hp->tty;
458 }
459
460 /*
461  * Returns true/false indicating data successfully read from hypervisor.
462  * Used both to get packets for tty connections and to advance the state
463  * machine during console handshaking (in which case tty = NULL and we ignore
464  * incoming data).
465  */
466 static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip,
467                 struct tty_struct **hangup, struct hvsi_struct **handshake)
468 {
469         uint8_t *packet = hp->inbuf;
470         int chunklen;
471
472         *flip = NULL;
473         *hangup = NULL;
474         *handshake = NULL;
475
476         chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
477         if (chunklen == 0) {
478                 pr_debug("%s: 0-length read\n", __FUNCTION__);
479                 return 0;
480         }
481
482         pr_debug("%s: got %i bytes\n", __FUNCTION__, chunklen);
483         dbg_dump_hex(hp->inbuf_end, chunklen);
484
485         hp->inbuf_end += chunklen;
486
487         /* handle all completed packets */
488         while ((packet < hp->inbuf_end) && got_packet(hp, packet)) {
489                 struct hvsi_header *header = (struct hvsi_header *)packet;
490
491                 if (!is_header(packet)) {
492                         printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index);
493                         /* skip bytes until we find a header or run out of data */
494                         while ((packet < hp->inbuf_end) && (!is_header(packet)))
495                                 packet++;
496                         continue;
497                 }
498
499                 pr_debug("%s: handling %i-byte packet\n", __FUNCTION__,
500                                 len_packet(packet));
501                 dbg_dump_packet(packet);
502
503                 switch (header->type) {
504                         case VS_DATA_PACKET_HEADER:
505                                 if (!is_open(hp))
506                                         break;
507                                 if (hp->tty == NULL)
508                                         break; /* no tty buffer to put data in */
509                                 *flip = hvsi_recv_data(hp, packet);
510                                 break;
511                         case VS_CONTROL_PACKET_HEADER:
512                                 hvsi_recv_control(hp, packet, hangup, handshake);
513                                 break;
514                         case VS_QUERY_RESPONSE_PACKET_HEADER:
515                                 hvsi_recv_response(hp, packet);
516                                 break;
517                         case VS_QUERY_PACKET_HEADER:
518                                 hvsi_recv_query(hp, packet);
519                                 break;
520                         default:
521                                 printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
522                                                 hp->index, header->type);
523                                 dump_packet(packet);
524                                 break;
525                 }
526
527                 packet += len_packet(packet);
528
529                 if (*hangup || *handshake) {
530                         pr_debug("%s: hangup or handshake\n", __FUNCTION__);
531                         /*
532                          * we need to send the hangup now before receiving any more data.
533                          * If we get "data, hangup, data", we can't deliver the second
534                          * data before the hangup.
535                          */
536                         break;
537                 }
538         }
539
540         compact_inbuf(hp, packet);
541
542         return 1;
543 }
544
545 static void hvsi_send_overflow(struct hvsi_struct *hp)
546 {
547         pr_debug("%s: delivering %i bytes overflow\n", __FUNCTION__,
548                         hp->n_throttle);
549
550         hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);
551         hp->n_throttle = 0;
552 }
553
554 /*
555  * must get all pending data because we only get an irq on empty->non-empty
556  * transition
557  */
558 static irqreturn_t hvsi_interrupt(int irq, void *arg)
559 {
560         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
561         struct tty_struct *flip;
562         struct tty_struct *hangup;
563         struct hvsi_struct *handshake;
564         unsigned long flags;
565         int again = 1;
566
567         pr_debug("%s\n", __FUNCTION__);
568
569         while (again) {
570                 spin_lock_irqsave(&hp->lock, flags);
571                 again = hvsi_load_chunk(hp, &flip, &hangup, &handshake);
572                 spin_unlock_irqrestore(&hp->lock, flags);
573
574                 /*
575                  * we have to call tty_flip_buffer_push() and tty_hangup() outside our
576                  * spinlock. But we also have to keep going until we've read all the
577                  * available data.
578                  */
579
580                 if (flip) {
581                         /* there was data put in the tty flip buffer */
582                         tty_flip_buffer_push(flip);
583                         flip = NULL;
584                 }
585
586                 if (hangup) {
587                         tty_hangup(hangup);
588                 }
589
590                 if (handshake) {
591                         pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
592                         schedule_work(&handshake->handshaker);
593                 }
594         }
595
596         spin_lock_irqsave(&hp->lock, flags);
597         if (hp->tty && hp->n_throttle
598                         && (!test_bit(TTY_THROTTLED, &hp->tty->flags))) {
599                 /* we weren't hung up and we weren't throttled, so we can deliver the
600                  * rest now */
601                 flip = hp->tty;
602                 hvsi_send_overflow(hp);
603         }
604         spin_unlock_irqrestore(&hp->lock, flags);
605
606         if (flip) {
607                 tty_flip_buffer_push(flip);
608         }
609
610         return IRQ_HANDLED;
611 }
612
613 /* for boot console, before the irq handler is running */
614 static int __init poll_for_state(struct hvsi_struct *hp, int state)
615 {
616         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
617
618         for (;;) {
619                 hvsi_interrupt(hp->virq, (void *)hp); /* get pending data */
620
621                 if (hp->state == state)
622                         return 0;
623
624                 mdelay(5);
625                 if (time_after(jiffies, end_jiffies))
626                         return -EIO;
627         }
628 }
629
630 /* wait for irq handler to change our state */
631 static int wait_for_state(struct hvsi_struct *hp, int state)
632 {
633         int ret = 0;
634
635         if (!wait_event_timeout(hp->stateq, (hp->state == state), HVSI_TIMEOUT))
636                 ret = -EIO;
637
638         return ret;
639 }
640
641 static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
642 {
643         struct hvsi_query packet __ALIGNED__;
644         int wrote;
645
646         packet.type = VS_QUERY_PACKET_HEADER;
647         packet.len = sizeof(struct hvsi_query);
648         packet.seqno = atomic_inc_return(&hp->seqno);
649         packet.verb = verb;
650
651         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
652         dbg_dump_hex((uint8_t*)&packet, packet.len);
653
654         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
655         if (wrote != packet.len) {
656                 printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
657                         wrote);
658                 return -EIO;
659         }
660
661         return 0;
662 }
663
664 static int hvsi_get_mctrl(struct hvsi_struct *hp)
665 {
666         int ret;
667
668         set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
669         hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
670
671         ret = hvsi_wait(hp, HVSI_OPEN);
672         if (ret < 0) {
673                 printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
674                 set_state(hp, HVSI_OPEN);
675                 return ret;
676         }
677
678         pr_debug("%s: mctrl 0x%x\n", __FUNCTION__, hp->mctrl);
679
680         return 0;
681 }
682
683 /* note that we can only set DTR */
684 static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
685 {
686         struct hvsi_control packet __ALIGNED__;
687         int wrote;
688
689         packet.type = VS_CONTROL_PACKET_HEADER,
690         packet.seqno = atomic_inc_return(&hp->seqno);
691         packet.len = sizeof(struct hvsi_control);
692         packet.verb = VSV_SET_MODEM_CTL;
693         packet.mask = HVSI_TSDTR;
694
695         if (mctrl & TIOCM_DTR)
696                 packet.word = HVSI_TSDTR;
697
698         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
699         dbg_dump_hex((uint8_t*)&packet, packet.len);
700
701         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
702         if (wrote != packet.len) {
703                 printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
704                 return -EIO;
705         }
706
707         return 0;
708 }
709
710 static void hvsi_drain_input(struct hvsi_struct *hp)
711 {
712         uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
713         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
714
715         while (time_before(end_jiffies, jiffies))
716                 if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
717                         break;
718 }
719
720 static int hvsi_handshake(struct hvsi_struct *hp)
721 {
722         int ret;
723
724         /*
725          * We could have a CLOSE or other data waiting for us before we even try
726          * to open; try to throw it all away so we don't get confused. (CLOSE
727          * is the first message sent up the pipe when the FSP comes online. We
728          * need to distinguish between "it came up a while ago and we're the first
729          * user" and "it was just reset before it saw our handshake packet".)
730          */
731         hvsi_drain_input(hp);
732
733         set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
734         ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
735         if (ret < 0) {
736                 printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
737                 return ret;
738         }
739
740         ret = hvsi_wait(hp, HVSI_OPEN);
741         if (ret < 0)
742                 return ret;
743
744         return 0;
745 }
746
747 static void hvsi_handshaker(void *arg)
748 {
749         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
750
751         if (hvsi_handshake(hp) >= 0)
752                 return;
753
754         printk(KERN_ERR "hvsi%i: re-handshaking failed\n", hp->index);
755         if (is_console(hp)) {
756                 /*
757                  * ttys will re-attempt the handshake via hvsi_open, but
758                  * the console will not.
759                  */
760                 printk(KERN_ERR "hvsi%i: lost console!\n", hp->index);
761         }
762 }
763
764 static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
765 {
766         struct hvsi_data packet __ALIGNED__;
767         int ret;
768
769         BUG_ON(count > HVSI_MAX_OUTGOING_DATA);
770
771         packet.type = VS_DATA_PACKET_HEADER;
772         packet.seqno = atomic_inc_return(&hp->seqno);
773         packet.len = count + sizeof(struct hvsi_header);
774         memcpy(&packet.data, buf, count);
775
776         ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
777         if (ret == packet.len) {
778                 /* return the number of chars written, not the packet length */
779                 return count;
780         }
781         return ret; /* return any errors */
782 }
783
784 static void hvsi_close_protocol(struct hvsi_struct *hp)
785 {
786         struct hvsi_control packet __ALIGNED__;
787
788         packet.type = VS_CONTROL_PACKET_HEADER;
789         packet.seqno = atomic_inc_return(&hp->seqno);
790         packet.len = 6;
791         packet.verb = VSV_CLOSE_PROTOCOL;
792
793         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
794         dbg_dump_hex((uint8_t*)&packet, packet.len);
795
796         hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
797 }
798
799 static int hvsi_open(struct tty_struct *tty, struct file *filp)
800 {
801         struct hvsi_struct *hp;
802         unsigned long flags;
803         int line = tty->index;
804         int ret;
805
806         pr_debug("%s\n", __FUNCTION__);
807
808         if (line < 0 || line >= hvsi_count)
809                 return -ENODEV;
810         hp = &hvsi_ports[line];
811
812         tty->driver_data = hp;
813         tty->low_latency = 1; /* avoid throttle/tty_flip_buffer_push race */
814
815         mb();
816         if (hp->state == HVSI_FSP_DIED)
817                 return -EIO;
818
819         spin_lock_irqsave(&hp->lock, flags);
820         hp->tty = tty;
821         hp->count++;
822         atomic_set(&hp->seqno, 0);
823         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
824         spin_unlock_irqrestore(&hp->lock, flags);
825
826         if (is_console(hp))
827                 return 0; /* this has already been handshaked as the console */
828
829         ret = hvsi_handshake(hp);
830         if (ret < 0) {
831                 printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
832                 return ret;
833         }
834
835         ret = hvsi_get_mctrl(hp);
836         if (ret < 0) {
837                 printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name);
838                 return ret;
839         }
840
841         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
842         if (ret < 0) {
843                 printk(KERN_ERR "%s: couldn't set DTR\n", tty->name);
844                 return ret;
845         }
846
847         return 0;
848 }
849
850 /* wait for hvsi_write_worker to empty hp->outbuf */
851 static void hvsi_flush_output(struct hvsi_struct *hp)
852 {
853         wait_event_timeout(hp->emptyq, (hp->n_outbuf <= 0), HVSI_TIMEOUT);
854
855         /* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */
856         cancel_delayed_work(&hp->writer);
857         flush_scheduled_work();
858
859         /*
860          * it's also possible that our timeout expired and hvsi_write_worker
861          * didn't manage to push outbuf. poof.
862          */
863         hp->n_outbuf = 0;
864 }
865
866 static void hvsi_close(struct tty_struct *tty, struct file *filp)
867 {
868         struct hvsi_struct *hp = tty->driver_data;
869         unsigned long flags;
870
871         pr_debug("%s\n", __FUNCTION__);
872
873         if (tty_hung_up_p(filp))
874                 return;
875
876         spin_lock_irqsave(&hp->lock, flags);
877
878         if (--hp->count == 0) {
879                 hp->tty = NULL;
880                 hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
881
882                 /* only close down connection if it is not the console */
883                 if (!is_console(hp)) {
884                         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */
885                         __set_state(hp, HVSI_CLOSED);
886                         /*
887                          * any data delivered to the tty layer after this will be
888                          * discarded (except for XON/XOFF)
889                          */
890                         tty->closing = 1;
891
892                         spin_unlock_irqrestore(&hp->lock, flags);
893
894                         /* let any existing irq handlers finish. no more will start. */
895                         synchronize_irq(hp->virq);
896
897                         /* hvsi_write_worker will re-schedule until outbuf is empty. */
898                         hvsi_flush_output(hp);
899
900                         /* tell FSP to stop sending data */
901                         hvsi_close_protocol(hp);
902
903                         /*
904                          * drain anything FSP is still in the middle of sending, and let
905                          * hvsi_handshake drain the rest on the next open.
906                          */
907                         hvsi_drain_input(hp);
908
909                         spin_lock_irqsave(&hp->lock, flags);
910                 }
911         } else if (hp->count < 0)
912                 printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n",
913                        hp - hvsi_ports, hp->count);
914
915         spin_unlock_irqrestore(&hp->lock, flags);
916 }
917
918 static void hvsi_hangup(struct tty_struct *tty)
919 {
920         struct hvsi_struct *hp = tty->driver_data;
921         unsigned long flags;
922
923         pr_debug("%s\n", __FUNCTION__);
924
925         spin_lock_irqsave(&hp->lock, flags);
926
927         hp->count = 0;
928         hp->n_outbuf = 0;
929         hp->tty = NULL;
930
931         spin_unlock_irqrestore(&hp->lock, flags);
932 }
933
934 /* called with hp->lock held */
935 static void hvsi_push(struct hvsi_struct *hp)
936 {
937         int n;
938
939         if (hp->n_outbuf <= 0)
940                 return;
941
942         n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf);
943         if (n > 0) {
944                 /* success */
945                 pr_debug("%s: wrote %i chars\n", __FUNCTION__, n);
946                 hp->n_outbuf = 0;
947         } else if (n == -EIO) {
948                 __set_state(hp, HVSI_FSP_DIED);
949                 printk(KERN_ERR "hvsi%i: service processor died\n", hp->index);
950         }
951 }
952
953 /* hvsi_write_worker will keep rescheduling itself until outbuf is empty */
954 static void hvsi_write_worker(void *arg)
955 {
956         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
957         unsigned long flags;
958 #ifdef DEBUG
959         static long start_j = 0;
960
961         if (start_j == 0)
962                 start_j = jiffies;
963 #endif /* DEBUG */
964
965         spin_lock_irqsave(&hp->lock, flags);
966
967         pr_debug("%s: %i chars in buffer\n", __FUNCTION__, hp->n_outbuf);
968
969         if (!is_open(hp)) {
970                 /*
971                  * We could have a non-open connection if the service processor died
972                  * while we were busily scheduling ourselves. In that case, it could
973                  * be minutes before the service processor comes back, so only try
974                  * again once a second.
975                  */
976                 schedule_delayed_work(&hp->writer, HZ);
977                 goto out;
978         }
979
980         hvsi_push(hp);
981         if (hp->n_outbuf > 0)
982                 schedule_delayed_work(&hp->writer, 10);
983         else {
984 #ifdef DEBUG
985                 pr_debug("%s: outbuf emptied after %li jiffies\n", __FUNCTION__,
986                                 jiffies - start_j);
987                 start_j = 0;
988 #endif /* DEBUG */
989                 wake_up_all(&hp->emptyq);
990                 tty_wakeup(hp->tty);
991         }
992
993 out:
994         spin_unlock_irqrestore(&hp->lock, flags);
995 }
996
997 static int hvsi_write_room(struct tty_struct *tty)
998 {
999         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1000
1001         return N_OUTBUF - hp->n_outbuf;
1002 }
1003
1004 static int hvsi_chars_in_buffer(struct tty_struct *tty)
1005 {
1006         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1007
1008         return hp->n_outbuf;
1009 }
1010
1011 static int hvsi_write(struct tty_struct *tty,
1012                      const unsigned char *buf, int count)
1013 {
1014         struct hvsi_struct *hp = tty->driver_data;
1015         const char *source = buf;
1016         unsigned long flags;
1017         int total = 0;
1018         int origcount = count;
1019
1020         spin_lock_irqsave(&hp->lock, flags);
1021
1022         pr_debug("%s: %i chars in buffer\n", __FUNCTION__, hp->n_outbuf);
1023
1024         if (!is_open(hp)) {
1025                 /* we're either closing or not yet open; don't accept data */
1026                 pr_debug("%s: not open\n", __FUNCTION__);
1027                 goto out;
1028         }
1029
1030         /*
1031          * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf
1032          * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls
1033          * will see there is no room in outbuf and return.
1034          */
1035         while ((count > 0) && (hvsi_write_room(hp->tty) > 0)) {
1036                 int chunksize = min(count, hvsi_write_room(hp->tty));
1037
1038                 BUG_ON(hp->n_outbuf < 0);
1039                 memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
1040                 hp->n_outbuf += chunksize;
1041
1042                 total += chunksize;
1043                 source += chunksize;
1044                 count -= chunksize;
1045                 hvsi_push(hp);
1046         }
1047
1048         if (hp->n_outbuf > 0) {
1049                 /*
1050                  * we weren't able to write it all to the hypervisor.
1051                  * schedule another push attempt.
1052                  */
1053                 schedule_delayed_work(&hp->writer, 10);
1054         }
1055
1056 out:
1057         spin_unlock_irqrestore(&hp->lock, flags);
1058
1059         if (total != origcount)
1060                 pr_debug("%s: wanted %i, only wrote %i\n", __FUNCTION__, origcount,
1061                         total);
1062
1063         return total;
1064 }
1065
1066 /*
1067  * I have never seen throttle or unthrottle called, so this little throttle
1068  * buffering scheme may or may not work.
1069  */
1070 static void hvsi_throttle(struct tty_struct *tty)
1071 {
1072         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1073
1074         pr_debug("%s\n", __FUNCTION__);
1075
1076         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE);
1077 }
1078
1079 static void hvsi_unthrottle(struct tty_struct *tty)
1080 {
1081         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1082         unsigned long flags;
1083         int shouldflip = 0;
1084
1085         pr_debug("%s\n", __FUNCTION__);
1086
1087         spin_lock_irqsave(&hp->lock, flags);
1088         if (hp->n_throttle) {
1089                 hvsi_send_overflow(hp);
1090                 shouldflip = 1;
1091         }
1092         spin_unlock_irqrestore(&hp->lock, flags);
1093
1094         if (shouldflip)
1095                 tty_flip_buffer_push(hp->tty);
1096
1097         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
1098 }
1099
1100 static int hvsi_tiocmget(struct tty_struct *tty, struct file *file)
1101 {
1102         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1103
1104         hvsi_get_mctrl(hp);
1105         return hp->mctrl;
1106 }
1107
1108 static int hvsi_tiocmset(struct tty_struct *tty, struct file *file,
1109                 unsigned int set, unsigned int clear)
1110 {
1111         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1112         unsigned long flags;
1113         uint16_t new_mctrl;
1114
1115         /* we can only alter DTR */
1116         clear &= TIOCM_DTR;
1117         set &= TIOCM_DTR;
1118
1119         spin_lock_irqsave(&hp->lock, flags);
1120
1121         new_mctrl = (hp->mctrl & ~clear) | set;
1122
1123         if (hp->mctrl != new_mctrl) {
1124                 hvsi_set_mctrl(hp, new_mctrl);
1125                 hp->mctrl = new_mctrl;
1126         }
1127         spin_unlock_irqrestore(&hp->lock, flags);
1128
1129         return 0;
1130 }
1131
1132
1133 static const struct tty_operations hvsi_ops = {
1134         .open = hvsi_open,
1135         .close = hvsi_close,
1136         .write = hvsi_write,
1137         .hangup = hvsi_hangup,
1138         .write_room = hvsi_write_room,
1139         .chars_in_buffer = hvsi_chars_in_buffer,
1140         .throttle = hvsi_throttle,
1141         .unthrottle = hvsi_unthrottle,
1142         .tiocmget = hvsi_tiocmget,
1143         .tiocmset = hvsi_tiocmset,
1144 };
1145
1146 static int __init hvsi_init(void)
1147 {
1148         int i;
1149
1150         hvsi_driver = alloc_tty_driver(hvsi_count);
1151         if (!hvsi_driver)
1152                 return -ENOMEM;
1153
1154         hvsi_driver->owner = THIS_MODULE;
1155         hvsi_driver->driver_name = "hvsi";
1156         hvsi_driver->name = "hvsi";
1157         hvsi_driver->major = HVSI_MAJOR;
1158         hvsi_driver->minor_start = HVSI_MINOR;
1159         hvsi_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1160         hvsi_driver->init_termios = tty_std_termios;
1161         hvsi_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
1162         hvsi_driver->flags = TTY_DRIVER_REAL_RAW;
1163         tty_set_operations(hvsi_driver, &hvsi_ops);
1164
1165         for (i=0; i < hvsi_count; i++) {
1166                 struct hvsi_struct *hp = &hvsi_ports[i];
1167                 int ret = 1;
1168
1169                 ret = request_irq(hp->virq, hvsi_interrupt, IRQF_DISABLED, "hvsi", hp);
1170                 if (ret)
1171                         printk(KERN_ERR "HVSI: couldn't reserve irq 0x%x (error %i)\n",
1172                                 hp->virq, ret);
1173         }
1174         hvsi_wait = wait_for_state; /* irqs active now */
1175
1176         if (tty_register_driver(hvsi_driver))
1177                 panic("Couldn't register hvsi console driver\n");
1178
1179         printk(KERN_DEBUG "HVSI: registered %i devices\n", hvsi_count);
1180
1181         return 0;
1182 }
1183 device_initcall(hvsi_init);
1184
1185 /***** console (not tty) code: *****/
1186
1187 static void hvsi_console_print(struct console *console, const char *buf,
1188                 unsigned int count)
1189 {
1190         struct hvsi_struct *hp = &hvsi_ports[console->index];
1191         char c[HVSI_MAX_OUTGOING_DATA] __ALIGNED__;
1192         unsigned int i = 0, n = 0;
1193         int ret, donecr = 0;
1194
1195         mb();
1196         if (!is_open(hp))
1197                 return;
1198
1199         /*
1200          * ugh, we have to translate LF -> CRLF ourselves, in place.
1201          * copied from hvc_console.c:
1202          */
1203         while (count > 0 || i > 0) {
1204                 if (count > 0 && i < sizeof(c)) {
1205                         if (buf[n] == '\n' && !donecr) {
1206                                 c[i++] = '\r';
1207                                 donecr = 1;
1208                         } else {
1209                                 c[i++] = buf[n++];
1210                                 donecr = 0;
1211                                 --count;
1212                         }
1213                 } else {
1214                         ret = hvsi_put_chars(hp, c, i);
1215                         if (ret < 0)
1216                                 i = 0;
1217                         i -= ret;
1218                 }
1219         }
1220 }
1221
1222 static struct tty_driver *hvsi_console_device(struct console *console,
1223         int *index)
1224 {
1225         *index = console->index;
1226         return hvsi_driver;
1227 }
1228
1229 static int __init hvsi_console_setup(struct console *console, char *options)
1230 {
1231         struct hvsi_struct *hp = &hvsi_ports[console->index];
1232         int ret;
1233
1234         if (console->index < 0 || console->index >= hvsi_count)
1235                 return -1;
1236
1237         /* give the FSP a chance to change the baud rate when we re-open */
1238         hvsi_close_protocol(hp);
1239
1240         ret = hvsi_handshake(hp);
1241         if (ret < 0)
1242                 return ret;
1243
1244         ret = hvsi_get_mctrl(hp);
1245         if (ret < 0)
1246                 return ret;
1247
1248         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
1249         if (ret < 0)
1250                 return ret;
1251
1252         hp->flags |= HVSI_CONSOLE;
1253
1254         return 0;
1255 }
1256
1257 static struct console hvsi_con_driver = {
1258         .name           = "hvsi",
1259         .write          = hvsi_console_print,
1260         .device         = hvsi_console_device,
1261         .setup          = hvsi_console_setup,
1262         .flags          = CON_PRINTBUFFER,
1263         .index          = -1,
1264 };
1265
1266 static int __init hvsi_console_init(void)
1267 {
1268         struct device_node *vty;
1269
1270         hvsi_wait = poll_for_state; /* no irqs yet; must poll */
1271
1272         /* search device tree for vty nodes */
1273         for (vty = of_find_compatible_node(NULL, "serial", "hvterm-protocol");
1274                         vty != NULL;
1275                         vty = of_find_compatible_node(vty, "serial", "hvterm-protocol")) {
1276                 struct hvsi_struct *hp;
1277                 const uint32_t *vtermno, *irq;
1278
1279                 vtermno = get_property(vty, "reg", NULL);
1280                 irq = get_property(vty, "interrupts", NULL);
1281                 if (!vtermno || !irq)
1282                         continue;
1283
1284                 if (hvsi_count >= MAX_NR_HVSI_CONSOLES) {
1285                         of_node_put(vty);
1286                         break;
1287                 }
1288
1289                 hp = &hvsi_ports[hvsi_count];
1290                 INIT_WORK(&hp->writer, hvsi_write_worker, hp);
1291                 INIT_WORK(&hp->handshaker, hvsi_handshaker, hp);
1292                 init_waitqueue_head(&hp->emptyq);
1293                 init_waitqueue_head(&hp->stateq);
1294                 spin_lock_init(&hp->lock);
1295                 hp->index = hvsi_count;
1296                 hp->inbuf_end = hp->inbuf;
1297                 hp->state = HVSI_CLOSED;
1298                 hp->vtermno = *vtermno;
1299                 hp->virq = irq_create_mapping(NULL, irq[0]);
1300                 if (hp->virq == NO_IRQ) {
1301                         printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
1302                                 __FUNCTION__, irq[0]);
1303                         continue;
1304                 }
1305
1306                 hvsi_count++;
1307         }
1308
1309         if (hvsi_count)
1310                 register_console(&hvsi_con_driver);
1311         return 0;
1312 }
1313 console_initcall(hvsi_console_init);