Linux-2.6.12-rc2
[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 > (sizeof(state_names)/sizeof(char*)))
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 /* can't use hvc_get_chars because that strips CRs */
295 static int hvsi_read(struct hvsi_struct *hp, char *buf, int count)
296 {
297         unsigned long got;
298
299         if (plpar_hcall(H_GET_TERM_CHAR, hp->vtermno, 0, 0, 0, &got,
300                         (unsigned long *)buf, (unsigned long *)buf+1) == H_Success)
301                 return got;
302         return 0;
303 }
304
305 static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet,
306         struct tty_struct **to_hangup, struct hvsi_struct **to_handshake)
307 {
308         struct hvsi_control *header = (struct hvsi_control *)packet;
309
310         switch (header->verb) {
311                 case VSV_MODEM_CTL_UPDATE:
312                         if ((header->word & HVSI_TSCD) == 0) {
313                                 /* CD went away; no more connection */
314                                 pr_debug("hvsi%i: CD dropped\n", hp->index);
315                                 hp->mctrl &= TIOCM_CD;
316                                 if (!(hp->tty->flags & CLOCAL))
317                                         *to_hangup = hp->tty;
318                         }
319                         break;
320                 case VSV_CLOSE_PROTOCOL:
321                         pr_debug("hvsi%i: service processor came back\n", hp->index);
322                         if (hp->state != HVSI_CLOSED) {
323                                 *to_handshake = hp;
324                         }
325                         break;
326                 default:
327                         printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ",
328                                 hp->index);
329                         dump_packet(packet);
330                         break;
331         }
332 }
333
334 static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet)
335 {
336         struct hvsi_query_response *resp = (struct hvsi_query_response *)packet;
337
338         switch (hp->state) {
339                 case HVSI_WAIT_FOR_VER_RESPONSE:
340                         __set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
341                         break;
342                 case HVSI_WAIT_FOR_MCTRL_RESPONSE:
343                         hp->mctrl = 0;
344                         if (resp->u.mctrl_word & HVSI_TSDTR)
345                                 hp->mctrl |= TIOCM_DTR;
346                         if (resp->u.mctrl_word & HVSI_TSCD)
347                                 hp->mctrl |= TIOCM_CD;
348                         __set_state(hp, HVSI_OPEN);
349                         break;
350                 default:
351                         printk(KERN_ERR "hvsi%i: unexpected query response: ", hp->index);
352                         dump_packet(packet);
353                         break;
354         }
355 }
356
357 /* respond to service processor's version query */
358 static int hvsi_version_respond(struct hvsi_struct *hp, uint16_t query_seqno)
359 {
360         struct hvsi_query_response packet __ALIGNED__;
361         int wrote;
362
363         packet.type = VS_QUERY_RESPONSE_PACKET_HEADER;
364         packet.len = sizeof(struct hvsi_query_response);
365         packet.seqno = atomic_inc_return(&hp->seqno);
366         packet.verb = VSV_SEND_VERSION_NUMBER;
367         packet.u.version = HVSI_VERSION;
368         packet.query_seqno = query_seqno+1;
369
370         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
371         dbg_dump_hex((uint8_t*)&packet, packet.len);
372
373         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
374         if (wrote != packet.len) {
375                 printk(KERN_ERR "hvsi%i: couldn't send query response!\n",
376                         hp->index);
377                 return -EIO;
378         }
379
380         return 0;
381 }
382
383 static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet)
384 {
385         struct hvsi_query *query = (struct hvsi_query *)packet;
386
387         switch (hp->state) {
388                 case HVSI_WAIT_FOR_VER_QUERY:
389                         hvsi_version_respond(hp, query->seqno);
390                         __set_state(hp, HVSI_OPEN);
391                         break;
392                 default:
393                         printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index);
394                         dump_packet(packet);
395                         break;
396         }
397 }
398
399 static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len)
400 {
401         int i;
402
403         for (i=0; i < len; i++) {
404                 char c = buf[i];
405 #ifdef CONFIG_MAGIC_SYSRQ
406                 if (c == '\0') {
407                         hp->sysrq = 1;
408                         continue;
409                 } else if (hp->sysrq) {
410                         handle_sysrq(c, NULL, hp->tty);
411                         hp->sysrq = 0;
412                         continue;
413                 }
414 #endif /* CONFIG_MAGIC_SYSRQ */
415                 tty_insert_flip_char(hp->tty, c, 0);
416         }
417 }
418
419 /*
420  * We could get 252 bytes of data at once here. But the tty layer only
421  * throttles us at TTY_THRESHOLD_THROTTLE (128) bytes, so we could overflow
422  * it. Accordingly we won't send more than 128 bytes at a time to the flip
423  * buffer, which will give the tty buffer a chance to throttle us. Should the
424  * value of TTY_THRESHOLD_THROTTLE change in n_tty.c, this code should be
425  * revisited.
426  */
427 #define TTY_THRESHOLD_THROTTLE 128
428 static struct tty_struct *hvsi_recv_data(struct hvsi_struct *hp,
429                 const uint8_t *packet)
430 {
431         const struct hvsi_header *header = (const struct hvsi_header *)packet;
432         const uint8_t *data = packet + sizeof(struct hvsi_header);
433         int datalen = header->len - sizeof(struct hvsi_header);
434         int overflow = datalen - TTY_THRESHOLD_THROTTLE;
435
436         pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data);
437
438         if (datalen == 0)
439                 return NULL;
440
441         if (overflow > 0) {
442                 pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __FUNCTION__);
443                 datalen = TTY_THRESHOLD_THROTTLE;
444         }
445
446         hvsi_insert_chars(hp, data, datalen);
447
448         if (overflow > 0) {
449                 /*
450                  * we still have more data to deliver, so we need to save off the
451                  * overflow and send it later
452                  */
453                 pr_debug("%s: deferring overflow\n", __FUNCTION__);
454                 memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow);
455                 hp->n_throttle = overflow;
456         }
457
458         return hp->tty;
459 }
460
461 /*
462  * Returns true/false indicating data successfully read from hypervisor.
463  * Used both to get packets for tty connections and to advance the state
464  * machine during console handshaking (in which case tty = NULL and we ignore
465  * incoming data).
466  */
467 static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip,
468                 struct tty_struct **hangup, struct hvsi_struct **handshake)
469 {
470         uint8_t *packet = hp->inbuf;
471         int chunklen;
472
473         *flip = NULL;
474         *hangup = NULL;
475         *handshake = NULL;
476
477         chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
478         if (chunklen == 0) {
479                 pr_debug("%s: 0-length read\n", __FUNCTION__);
480                 return 0;
481         }
482
483         pr_debug("%s: got %i bytes\n", __FUNCTION__, chunklen);
484         dbg_dump_hex(hp->inbuf_end, chunklen);
485
486         hp->inbuf_end += chunklen;
487
488         /* handle all completed packets */
489         while ((packet < hp->inbuf_end) && got_packet(hp, packet)) {
490                 struct hvsi_header *header = (struct hvsi_header *)packet;
491
492                 if (!is_header(packet)) {
493                         printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index);
494                         /* skip bytes until we find a header or run out of data */
495                         while ((packet < hp->inbuf_end) && (!is_header(packet)))
496                                 packet++;
497                         continue;
498                 }
499
500                 pr_debug("%s: handling %i-byte packet\n", __FUNCTION__,
501                                 len_packet(packet));
502                 dbg_dump_packet(packet);
503
504                 switch (header->type) {
505                         case VS_DATA_PACKET_HEADER:
506                                 if (!is_open(hp))
507                                         break;
508                                 if (hp->tty == NULL)
509                                         break; /* no tty buffer to put data in */
510                                 *flip = hvsi_recv_data(hp, packet);
511                                 break;
512                         case VS_CONTROL_PACKET_HEADER:
513                                 hvsi_recv_control(hp, packet, hangup, handshake);
514                                 break;
515                         case VS_QUERY_RESPONSE_PACKET_HEADER:
516                                 hvsi_recv_response(hp, packet);
517                                 break;
518                         case VS_QUERY_PACKET_HEADER:
519                                 hvsi_recv_query(hp, packet);
520                                 break;
521                         default:
522                                 printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
523                                                 hp->index, header->type);
524                                 dump_packet(packet);
525                                 break;
526                 }
527
528                 packet += len_packet(packet);
529
530                 if (*hangup || *handshake) {
531                         pr_debug("%s: hangup or handshake\n", __FUNCTION__);
532                         /*
533                          * we need to send the hangup now before receiving any more data.
534                          * If we get "data, hangup, data", we can't deliver the second
535                          * data before the hangup.
536                          */
537                         break;
538                 }
539         }
540
541         compact_inbuf(hp, packet);
542
543         return 1;
544 }
545
546 static void hvsi_send_overflow(struct hvsi_struct *hp)
547 {
548         pr_debug("%s: delivering %i bytes overflow\n", __FUNCTION__,
549                         hp->n_throttle);
550
551         hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);
552         hp->n_throttle = 0;
553 }
554
555 /*
556  * must get all pending data because we only get an irq on empty->non-empty
557  * transition
558  */
559 static irqreturn_t hvsi_interrupt(int irq, void *arg, struct pt_regs *regs)
560 {
561         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
562         struct tty_struct *flip;
563         struct tty_struct *hangup;
564         struct hvsi_struct *handshake;
565         unsigned long flags;
566         int again = 1;
567
568         pr_debug("%s\n", __FUNCTION__);
569
570         while (again) {
571                 spin_lock_irqsave(&hp->lock, flags);
572                 again = hvsi_load_chunk(hp, &flip, &hangup, &handshake);
573                 spin_unlock_irqrestore(&hp->lock, flags);
574
575                 /*
576                  * we have to call tty_flip_buffer_push() and tty_hangup() outside our
577                  * spinlock. But we also have to keep going until we've read all the
578                  * available data.
579                  */
580
581                 if (flip) {
582                         /* there was data put in the tty flip buffer */
583                         tty_flip_buffer_push(flip);
584                         flip = NULL;
585                 }
586
587                 if (hangup) {
588                         tty_hangup(hangup);
589                 }
590
591                 if (handshake) {
592                         pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
593                         schedule_work(&handshake->handshaker);
594                 }
595         }
596
597         spin_lock_irqsave(&hp->lock, flags);
598         if (hp->tty && hp->n_throttle
599                         && (!test_bit(TTY_THROTTLED, &hp->tty->flags))) {
600                 /* we weren't hung up and we weren't throttled, so we can deliver the
601                  * rest now */
602                 flip = hp->tty;
603                 hvsi_send_overflow(hp);
604         }
605         spin_unlock_irqrestore(&hp->lock, flags);
606
607         if (flip) {
608                 tty_flip_buffer_push(flip);
609         }
610
611         return IRQ_HANDLED;
612 }
613
614 /* for boot console, before the irq handler is running */
615 static int __init poll_for_state(struct hvsi_struct *hp, int state)
616 {
617         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
618
619         for (;;) {
620                 hvsi_interrupt(hp->virq, (void *)hp, NULL); /* get pending data */
621
622                 if (hp->state == state)
623                         return 0;
624
625                 mdelay(5);
626                 if (time_after(jiffies, end_jiffies))
627                         return -EIO;
628         }
629 }
630
631 /* wait for irq handler to change our state */
632 static int wait_for_state(struct hvsi_struct *hp, int state)
633 {
634         int ret = 0;
635
636         if (!wait_event_timeout(hp->stateq, (hp->state == state), HVSI_TIMEOUT))
637                 ret = -EIO;
638
639         return ret;
640 }
641
642 static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
643 {
644         struct hvsi_query packet __ALIGNED__;
645         int wrote;
646
647         packet.type = VS_QUERY_PACKET_HEADER;
648         packet.len = sizeof(struct hvsi_query);
649         packet.seqno = atomic_inc_return(&hp->seqno);
650         packet.verb = verb;
651
652         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
653         dbg_dump_hex((uint8_t*)&packet, packet.len);
654
655         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
656         if (wrote != packet.len) {
657                 printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
658                         wrote);
659                 return -EIO;
660         }
661
662         return 0;
663 }
664
665 static int hvsi_get_mctrl(struct hvsi_struct *hp)
666 {
667         int ret;
668
669         set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
670         hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
671
672         ret = hvsi_wait(hp, HVSI_OPEN);
673         if (ret < 0) {
674                 printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
675                 set_state(hp, HVSI_OPEN);
676                 return ret;
677         }
678
679         pr_debug("%s: mctrl 0x%x\n", __FUNCTION__, hp->mctrl);
680
681         return 0;
682 }
683
684 /* note that we can only set DTR */
685 static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
686 {
687         struct hvsi_control packet __ALIGNED__;
688         int wrote;
689
690         packet.type = VS_CONTROL_PACKET_HEADER,
691         packet.seqno = atomic_inc_return(&hp->seqno);
692         packet.len = sizeof(struct hvsi_control);
693         packet.verb = VSV_SET_MODEM_CTL;
694         packet.mask = HVSI_TSDTR;
695
696         if (mctrl & TIOCM_DTR)
697                 packet.word = HVSI_TSDTR;
698
699         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
700         dbg_dump_hex((uint8_t*)&packet, packet.len);
701
702         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
703         if (wrote != packet.len) {
704                 printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
705                 return -EIO;
706         }
707
708         return 0;
709 }
710
711 static void hvsi_drain_input(struct hvsi_struct *hp)
712 {
713         uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
714         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
715
716         while (time_before(end_jiffies, jiffies))
717                 if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
718                         break;
719 }
720
721 static int hvsi_handshake(struct hvsi_struct *hp)
722 {
723         int ret;
724
725         /*
726          * We could have a CLOSE or other data waiting for us before we even try
727          * to open; try to throw it all away so we don't get confused. (CLOSE
728          * is the first message sent up the pipe when the FSP comes online. We
729          * need to distinguish between "it came up a while ago and we're the first
730          * user" and "it was just reset before it saw our handshake packet".)
731          */
732         hvsi_drain_input(hp);
733
734         set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
735         ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
736         if (ret < 0) {
737                 printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
738                 return ret;
739         }
740
741         ret = hvsi_wait(hp, HVSI_OPEN);
742         if (ret < 0)
743                 return ret;
744
745         return 0;
746 }
747
748 static void hvsi_handshaker(void *arg)
749 {
750         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
751
752         if (hvsi_handshake(hp) >= 0)
753                 return;
754
755         printk(KERN_ERR "hvsi%i: re-handshaking failed\n", hp->index);
756         if (is_console(hp)) {
757                 /*
758                  * ttys will re-attempt the handshake via hvsi_open, but
759                  * the console will not.
760                  */
761                 printk(KERN_ERR "hvsi%i: lost console!\n", hp->index);
762         }
763 }
764
765 static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
766 {
767         struct hvsi_data packet __ALIGNED__;
768         int ret;
769
770         BUG_ON(count > HVSI_MAX_OUTGOING_DATA);
771
772         packet.type = VS_DATA_PACKET_HEADER;
773         packet.seqno = atomic_inc_return(&hp->seqno);
774         packet.len = count + sizeof(struct hvsi_header);
775         memcpy(&packet.data, buf, count);
776
777         ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
778         if (ret == packet.len) {
779                 /* return the number of chars written, not the packet length */
780                 return count;
781         }
782         return ret; /* return any errors */
783 }
784
785 static void hvsi_close_protocol(struct hvsi_struct *hp)
786 {
787         struct hvsi_control packet __ALIGNED__;
788
789         packet.type = VS_CONTROL_PACKET_HEADER;
790         packet.seqno = atomic_inc_return(&hp->seqno);
791         packet.len = 6;
792         packet.verb = VSV_CLOSE_PROTOCOL;
793
794         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
795         dbg_dump_hex((uint8_t*)&packet, packet.len);
796
797         hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
798 }
799
800 static int hvsi_open(struct tty_struct *tty, struct file *filp)
801 {
802         struct hvsi_struct *hp;
803         unsigned long flags;
804         int line = tty->index;
805         int ret;
806
807         pr_debug("%s\n", __FUNCTION__);
808
809         if (line < 0 || line >= hvsi_count)
810                 return -ENODEV;
811         hp = &hvsi_ports[line];
812
813         tty->driver_data = hp;
814         tty->low_latency = 1; /* avoid throttle/tty_flip_buffer_push race */
815
816         mb();
817         if (hp->state == HVSI_FSP_DIED)
818                 return -EIO;
819
820         spin_lock_irqsave(&hp->lock, flags);
821         hp->tty = tty;
822         hp->count++;
823         atomic_set(&hp->seqno, 0);
824         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
825         spin_unlock_irqrestore(&hp->lock, flags);
826
827         if (is_console(hp))
828                 return 0; /* this has already been handshaked as the console */
829
830         ret = hvsi_handshake(hp);
831         if (ret < 0) {
832                 printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
833                 return ret;
834         }
835
836         ret = hvsi_get_mctrl(hp);
837         if (ret < 0) {
838                 printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name);
839                 return ret;
840         }
841
842         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
843         if (ret < 0) {
844                 printk(KERN_ERR "%s: couldn't set DTR\n", tty->name);
845                 return ret;
846         }
847
848         return 0;
849 }
850
851 /* wait for hvsi_write_worker to empty hp->outbuf */
852 static void hvsi_flush_output(struct hvsi_struct *hp)
853 {
854         wait_event_timeout(hp->emptyq, (hp->n_outbuf <= 0), HVSI_TIMEOUT);
855
856         /* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */
857         cancel_delayed_work(&hp->writer);
858         flush_scheduled_work();
859
860         /*
861          * it's also possible that our timeout expired and hvsi_write_worker
862          * didn't manage to push outbuf. poof.
863          */
864         hp->n_outbuf = 0;
865 }
866
867 static void hvsi_close(struct tty_struct *tty, struct file *filp)
868 {
869         struct hvsi_struct *hp = tty->driver_data;
870         unsigned long flags;
871
872         pr_debug("%s\n", __FUNCTION__);
873
874         if (tty_hung_up_p(filp))
875                 return;
876
877         spin_lock_irqsave(&hp->lock, flags);
878
879         if (--hp->count == 0) {
880                 hp->tty = NULL;
881                 hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
882
883                 /* only close down connection if it is not the console */
884                 if (!is_console(hp)) {
885                         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */
886                         __set_state(hp, HVSI_CLOSED);
887                         /*
888                          * any data delivered to the tty layer after this will be
889                          * discarded (except for XON/XOFF)
890                          */
891                         tty->closing = 1;
892
893                         spin_unlock_irqrestore(&hp->lock, flags);
894
895                         /* let any existing irq handlers finish. no more will start. */
896                         synchronize_irq(hp->virq);
897
898                         /* hvsi_write_worker will re-schedule until outbuf is empty. */
899                         hvsi_flush_output(hp);
900
901                         /* tell FSP to stop sending data */
902                         hvsi_close_protocol(hp);
903
904                         /*
905                          * drain anything FSP is still in the middle of sending, and let
906                          * hvsi_handshake drain the rest on the next open.
907                          */
908                         hvsi_drain_input(hp);
909
910                         spin_lock_irqsave(&hp->lock, flags);
911                 }
912         } else if (hp->count < 0)
913                 printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n",
914                        hp - hvsi_ports, hp->count);
915
916         spin_unlock_irqrestore(&hp->lock, flags);
917 }
918
919 static void hvsi_hangup(struct tty_struct *tty)
920 {
921         struct hvsi_struct *hp = tty->driver_data;
922         unsigned long flags;
923
924         pr_debug("%s\n", __FUNCTION__);
925
926         spin_lock_irqsave(&hp->lock, flags);
927
928         hp->count = 0;
929         hp->n_outbuf = 0;
930         hp->tty = NULL;
931
932         spin_unlock_irqrestore(&hp->lock, flags);
933 }
934
935 /* called with hp->lock held */
936 static void hvsi_push(struct hvsi_struct *hp)
937 {
938         int n;
939
940         if (hp->n_outbuf <= 0)
941                 return;
942
943         n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf);
944         if (n > 0) {
945                 /* success */
946                 pr_debug("%s: wrote %i chars\n", __FUNCTION__, n);
947                 hp->n_outbuf = 0;
948         } else if (n == -EIO) {
949                 __set_state(hp, HVSI_FSP_DIED);
950                 printk(KERN_ERR "hvsi%i: service processor died\n", hp->index);
951         }
952 }
953
954 /* hvsi_write_worker will keep rescheduling itself until outbuf is empty */
955 static void hvsi_write_worker(void *arg)
956 {
957         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
958         unsigned long flags;
959 #ifdef DEBUG
960         static long start_j = 0;
961
962         if (start_j == 0)
963                 start_j = jiffies;
964 #endif /* DEBUG */
965
966         spin_lock_irqsave(&hp->lock, flags);
967
968         pr_debug("%s: %i chars in buffer\n", __FUNCTION__, hp->n_outbuf);
969
970         if (!is_open(hp)) {
971                 /*
972                  * We could have a non-open connection if the service processor died
973                  * while we were busily scheduling ourselves. In that case, it could
974                  * be minutes before the service processor comes back, so only try
975                  * again once a second.
976                  */
977                 schedule_delayed_work(&hp->writer, HZ);
978                 goto out;
979         }
980
981         hvsi_push(hp);
982         if (hp->n_outbuf > 0)
983                 schedule_delayed_work(&hp->writer, 10);
984         else {
985 #ifdef DEBUG
986                 pr_debug("%s: outbuf emptied after %li jiffies\n", __FUNCTION__,
987                                 jiffies - start_j);
988                 start_j = 0;
989 #endif /* DEBUG */
990                 wake_up_all(&hp->emptyq);
991                 if (test_bit(TTY_DO_WRITE_WAKEUP, &hp->tty->flags)
992                                 && hp->tty->ldisc.write_wakeup)
993                         hp->tty->ldisc.write_wakeup(hp->tty);
994                 wake_up_interruptible(&hp->tty->write_wait);
995         }
996
997 out:
998         spin_unlock_irqrestore(&hp->lock, flags);
999 }
1000
1001 static int hvsi_write_room(struct tty_struct *tty)
1002 {
1003         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1004
1005         return N_OUTBUF - hp->n_outbuf;
1006 }
1007
1008 static int hvsi_chars_in_buffer(struct tty_struct *tty)
1009 {
1010         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1011
1012         return hp->n_outbuf;
1013 }
1014
1015 static int hvsi_write(struct tty_struct *tty,
1016                      const unsigned char *buf, int count)
1017 {
1018         struct hvsi_struct *hp = tty->driver_data;
1019         const char *source = buf;
1020         unsigned long flags;
1021         int total = 0;
1022         int origcount = count;
1023
1024         spin_lock_irqsave(&hp->lock, flags);
1025
1026         pr_debug("%s: %i chars in buffer\n", __FUNCTION__, hp->n_outbuf);
1027
1028         if (!is_open(hp)) {
1029                 /* we're either closing or not yet open; don't accept data */
1030                 pr_debug("%s: not open\n", __FUNCTION__);
1031                 goto out;
1032         }
1033
1034         /*
1035          * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf
1036          * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls
1037          * will see there is no room in outbuf and return.
1038          */
1039         while ((count > 0) && (hvsi_write_room(hp->tty) > 0)) {
1040                 int chunksize = min(count, hvsi_write_room(hp->tty));
1041
1042                 BUG_ON(hp->n_outbuf < 0);
1043                 memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
1044                 hp->n_outbuf += chunksize;
1045
1046                 total += chunksize;
1047                 source += chunksize;
1048                 count -= chunksize;
1049                 hvsi_push(hp);
1050         }
1051
1052         if (hp->n_outbuf > 0) {
1053                 /*
1054                  * we weren't able to write it all to the hypervisor.
1055                  * schedule another push attempt.
1056                  */
1057                 schedule_delayed_work(&hp->writer, 10);
1058         }
1059
1060 out:
1061         spin_unlock_irqrestore(&hp->lock, flags);
1062
1063         if (total != origcount)
1064                 pr_debug("%s: wanted %i, only wrote %i\n", __FUNCTION__, origcount,
1065                         total);
1066
1067         return total;
1068 }
1069
1070 /*
1071  * I have never seen throttle or unthrottle called, so this little throttle
1072  * buffering scheme may or may not work.
1073  */
1074 static void hvsi_throttle(struct tty_struct *tty)
1075 {
1076         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1077
1078         pr_debug("%s\n", __FUNCTION__);
1079
1080         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE);
1081 }
1082
1083 static void hvsi_unthrottle(struct tty_struct *tty)
1084 {
1085         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1086         unsigned long flags;
1087         int shouldflip = 0;
1088
1089         pr_debug("%s\n", __FUNCTION__);
1090
1091         spin_lock_irqsave(&hp->lock, flags);
1092         if (hp->n_throttle) {
1093                 hvsi_send_overflow(hp);
1094                 shouldflip = 1;
1095         }
1096         spin_unlock_irqrestore(&hp->lock, flags);
1097
1098         if (shouldflip)
1099                 tty_flip_buffer_push(hp->tty);
1100
1101         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
1102 }
1103
1104 static int hvsi_tiocmget(struct tty_struct *tty, struct file *file)
1105 {
1106         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1107
1108         hvsi_get_mctrl(hp);
1109         return hp->mctrl;
1110 }
1111
1112 static int hvsi_tiocmset(struct tty_struct *tty, struct file *file,
1113                 unsigned int set, unsigned int clear)
1114 {
1115         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1116         unsigned long flags;
1117         uint16_t new_mctrl;
1118
1119         /* we can only alter DTR */
1120         clear &= TIOCM_DTR;
1121         set &= TIOCM_DTR;
1122
1123         spin_lock_irqsave(&hp->lock, flags);
1124
1125         new_mctrl = (hp->mctrl & ~clear) | set;
1126
1127         if (hp->mctrl != new_mctrl) {
1128                 hvsi_set_mctrl(hp, new_mctrl);
1129                 hp->mctrl = new_mctrl;
1130         }
1131         spin_unlock_irqrestore(&hp->lock, flags);
1132
1133         return 0;
1134 }
1135
1136
1137 static struct tty_operations hvsi_ops = {
1138         .open = hvsi_open,
1139         .close = hvsi_close,
1140         .write = hvsi_write,
1141         .hangup = hvsi_hangup,
1142         .write_room = hvsi_write_room,
1143         .chars_in_buffer = hvsi_chars_in_buffer,
1144         .throttle = hvsi_throttle,
1145         .unthrottle = hvsi_unthrottle,
1146         .tiocmget = hvsi_tiocmget,
1147         .tiocmset = hvsi_tiocmset,
1148 };
1149
1150 static int __init hvsi_init(void)
1151 {
1152         int i;
1153
1154         hvsi_driver = alloc_tty_driver(hvsi_count);
1155         if (!hvsi_driver)
1156                 return -ENOMEM;
1157
1158         hvsi_driver->owner = THIS_MODULE;
1159         hvsi_driver->devfs_name = "hvsi/";
1160         hvsi_driver->driver_name = "hvsi";
1161         hvsi_driver->name = "hvsi";
1162         hvsi_driver->major = HVSI_MAJOR;
1163         hvsi_driver->minor_start = HVSI_MINOR;
1164         hvsi_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1165         hvsi_driver->init_termios = tty_std_termios;
1166         hvsi_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
1167         hvsi_driver->flags = TTY_DRIVER_REAL_RAW;
1168         tty_set_operations(hvsi_driver, &hvsi_ops);
1169
1170         for (i=0; i < hvsi_count; i++) {
1171                 struct hvsi_struct *hp = &hvsi_ports[i];
1172                 int ret = 1;
1173
1174                 ret = request_irq(hp->virq, hvsi_interrupt, SA_INTERRUPT, "hvsi", hp);
1175                 if (ret)
1176                         printk(KERN_ERR "HVSI: couldn't reserve irq 0x%x (error %i)\n",
1177                                 hp->virq, ret);
1178         }
1179         hvsi_wait = wait_for_state; /* irqs active now */
1180
1181         if (tty_register_driver(hvsi_driver))
1182                 panic("Couldn't register hvsi console driver\n");
1183
1184         printk(KERN_INFO "HVSI: registered %i devices\n", hvsi_count);
1185
1186         return 0;
1187 }
1188 device_initcall(hvsi_init);
1189
1190 /***** console (not tty) code: *****/
1191
1192 static void hvsi_console_print(struct console *console, const char *buf,
1193                 unsigned int count)
1194 {
1195         struct hvsi_struct *hp = &hvsi_ports[console->index];
1196         char c[HVSI_MAX_OUTGOING_DATA] __ALIGNED__;
1197         unsigned int i = 0, n = 0;
1198         int ret, donecr = 0;
1199
1200         mb();
1201         if (!is_open(hp))
1202                 return;
1203
1204         /*
1205          * ugh, we have to translate LF -> CRLF ourselves, in place.
1206          * copied from hvc_console.c:
1207          */
1208         while (count > 0 || i > 0) {
1209                 if (count > 0 && i < sizeof(c)) {
1210                         if (buf[n] == '\n' && !donecr) {
1211                                 c[i++] = '\r';
1212                                 donecr = 1;
1213                         } else {
1214                                 c[i++] = buf[n++];
1215                                 donecr = 0;
1216                                 --count;
1217                         }
1218                 } else {
1219                         ret = hvsi_put_chars(hp, c, i);
1220                         if (ret < 0)
1221                                 i = 0;
1222                         i -= ret;
1223                 }
1224         }
1225 }
1226
1227 static struct tty_driver *hvsi_console_device(struct console *console,
1228         int *index)
1229 {
1230         *index = console->index;
1231         return hvsi_driver;
1232 }
1233
1234 static int __init hvsi_console_setup(struct console *console, char *options)
1235 {
1236         struct hvsi_struct *hp = &hvsi_ports[console->index];
1237         int ret;
1238
1239         if (console->index < 0 || console->index >= hvsi_count)
1240                 return -1;
1241
1242         /* give the FSP a chance to change the baud rate when we re-open */
1243         hvsi_close_protocol(hp);
1244
1245         ret = hvsi_handshake(hp);
1246         if (ret < 0)
1247                 return ret;
1248
1249         ret = hvsi_get_mctrl(hp);
1250         if (ret < 0)
1251                 return ret;
1252
1253         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
1254         if (ret < 0)
1255                 return ret;
1256
1257         hp->flags |= HVSI_CONSOLE;
1258
1259         return 0;
1260 }
1261
1262 static struct console hvsi_con_driver = {
1263         .name           = "hvsi",
1264         .write          = hvsi_console_print,
1265         .device         = hvsi_console_device,
1266         .setup          = hvsi_console_setup,
1267         .flags          = CON_PRINTBUFFER,
1268         .index          = -1,
1269 };
1270
1271 static int __init hvsi_console_init(void)
1272 {
1273         struct device_node *vty;
1274
1275         hvsi_wait = poll_for_state; /* no irqs yet; must poll */
1276
1277         /* search device tree for vty nodes */
1278         for (vty = of_find_compatible_node(NULL, "serial", "hvterm-protocol");
1279                         vty != NULL;
1280                         vty = of_find_compatible_node(vty, "serial", "hvterm-protocol")) {
1281                 struct hvsi_struct *hp;
1282                 uint32_t *vtermno;
1283                 uint32_t *irq;
1284
1285                 vtermno = (uint32_t *)get_property(vty, "reg", NULL);
1286                 irq = (uint32_t *)get_property(vty, "interrupts", NULL);
1287                 if (!vtermno || !irq)
1288                         continue;
1289
1290                 if (hvsi_count >= MAX_NR_HVSI_CONSOLES) {
1291                         of_node_put(vty);
1292                         break;
1293                 }
1294
1295                 hp = &hvsi_ports[hvsi_count];
1296                 INIT_WORK(&hp->writer, hvsi_write_worker, hp);
1297                 INIT_WORK(&hp->handshaker, hvsi_handshaker, hp);
1298                 init_waitqueue_head(&hp->emptyq);
1299                 init_waitqueue_head(&hp->stateq);
1300                 spin_lock_init(&hp->lock);
1301                 hp->index = hvsi_count;
1302                 hp->inbuf_end = hp->inbuf;
1303                 hp->state = HVSI_CLOSED;
1304                 hp->vtermno = *vtermno;
1305                 hp->virq = virt_irq_create_mapping(irq[0]);
1306                 if (hp->virq == NO_IRQ) {
1307                         printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
1308                                 __FUNCTION__, hp->virq);
1309                         continue;
1310                 } else
1311                         hp->virq = irq_offset_up(hp->virq);
1312
1313                 hvsi_count++;
1314         }
1315
1316         if (hvsi_count)
1317                 register_console(&hvsi_con_driver);
1318         return 0;
1319 }
1320 console_initcall(hvsi_console_init);