Merge master.kernel.org:/home/rmk/linux-2.6-arm
[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/spinlock.h>
43 #include <linux/sysrq.h>
44 #include <linux/tty.h>
45 #include <linux/tty_flip.h>
46 #include <asm/hvcall.h>
47 #include <asm/hvconsole.h>
48 #include <asm/prom.h>
49 #include <asm/uaccess.h>
50 #include <asm/vio.h>
51 #include <asm/param.h>
52
53 #define HVSI_MAJOR      229
54 #define HVSI_MINOR      128
55 #define MAX_NR_HVSI_CONSOLES 4
56
57 #define HVSI_TIMEOUT (5*HZ)
58 #define HVSI_VERSION 1
59 #define HVSI_MAX_PACKET 256
60 #define HVSI_MAX_READ 16
61 #define HVSI_MAX_OUTGOING_DATA 12
62 #define N_OUTBUF 12
63
64 /*
65  * we pass data via two 8-byte registers, so we would like our char arrays
66  * properly aligned for those loads.
67  */
68 #define __ALIGNED__     __attribute__((__aligned__(sizeof(long))))
69
70 struct hvsi_struct {
71         struct delayed_work writer;
72         struct work_struct handshaker;
73         wait_queue_head_t emptyq; /* woken when outbuf is emptied */
74         wait_queue_head_t stateq; /* woken when HVSI state changes */
75         spinlock_t lock;
76         int index;
77         struct tty_struct *tty;
78         int count;
79         uint8_t throttle_buf[128];
80         uint8_t outbuf[N_OUTBUF]; /* to implement write_room and chars_in_buffer */
81         /* inbuf is for packet reassembly. leave a little room for leftovers. */
82         uint8_t inbuf[HVSI_MAX_PACKET + HVSI_MAX_READ];
83         uint8_t *inbuf_end;
84         int n_throttle;
85         int n_outbuf;
86         uint32_t vtermno;
87         uint32_t virq;
88         atomic_t seqno; /* HVSI packet sequence number */
89         uint16_t mctrl;
90         uint8_t state;  /* HVSI protocol state */
91         uint8_t flags;
92 #ifdef CONFIG_MAGIC_SYSRQ
93         uint8_t sysrq;
94 #endif /* CONFIG_MAGIC_SYSRQ */
95 };
96 static struct hvsi_struct hvsi_ports[MAX_NR_HVSI_CONSOLES];
97
98 static struct tty_driver *hvsi_driver;
99 static int hvsi_count;
100 static int (*hvsi_wait)(struct hvsi_struct *hp, int state);
101
102 enum HVSI_PROTOCOL_STATE {
103         HVSI_CLOSED,
104         HVSI_WAIT_FOR_VER_RESPONSE,
105         HVSI_WAIT_FOR_VER_QUERY,
106         HVSI_OPEN,
107         HVSI_WAIT_FOR_MCTRL_RESPONSE,
108         HVSI_FSP_DIED,
109 };
110 #define HVSI_CONSOLE 0x1
111
112 #define VS_DATA_PACKET_HEADER           0xff
113 #define VS_CONTROL_PACKET_HEADER        0xfe
114 #define VS_QUERY_PACKET_HEADER          0xfd
115 #define VS_QUERY_RESPONSE_PACKET_HEADER 0xfc
116
117 /* control verbs */
118 #define VSV_SET_MODEM_CTL    1 /* to service processor only */
119 #define VSV_MODEM_CTL_UPDATE 2 /* from service processor only */
120 #define VSV_CLOSE_PROTOCOL   3
121
122 /* query verbs */
123 #define VSV_SEND_VERSION_NUMBER 1
124 #define VSV_SEND_MODEM_CTL_STATUS 2
125
126 /* yes, these masks are not consecutive. */
127 #define HVSI_TSDTR 0x01
128 #define HVSI_TSCD  0x20
129
130 struct hvsi_header {
131         uint8_t  type;
132         uint8_t  len;
133         uint16_t seqno;
134 } __attribute__((packed));
135
136 struct hvsi_data {
137         uint8_t  type;
138         uint8_t  len;
139         uint16_t seqno;
140         uint8_t  data[HVSI_MAX_OUTGOING_DATA];
141 } __attribute__((packed));
142
143 struct hvsi_control {
144         uint8_t  type;
145         uint8_t  len;
146         uint16_t seqno;
147         uint16_t verb;
148         /* optional depending on verb: */
149         uint32_t word;
150         uint32_t mask;
151 } __attribute__((packed));
152
153 struct hvsi_query {
154         uint8_t  type;
155         uint8_t  len;
156         uint16_t seqno;
157         uint16_t verb;
158 } __attribute__((packed));
159
160 struct hvsi_query_response {
161         uint8_t  type;
162         uint8_t  len;
163         uint16_t seqno;
164         uint16_t verb;
165         uint16_t query_seqno;
166         union {
167                 uint8_t  version;
168                 uint32_t mctrl_word;
169         } u;
170 } __attribute__((packed));
171
172
173
174 static inline int is_console(struct hvsi_struct *hp)
175 {
176         return hp->flags & HVSI_CONSOLE;
177 }
178
179 static inline int is_open(struct hvsi_struct *hp)
180 {
181         /* if we're waiting for an mctrl then we're already open */
182         return (hp->state == HVSI_OPEN)
183                         || (hp->state == HVSI_WAIT_FOR_MCTRL_RESPONSE);
184 }
185
186 static inline void print_state(struct hvsi_struct *hp)
187 {
188 #ifdef DEBUG
189         static const char *state_names[] = {
190                 "HVSI_CLOSED",
191                 "HVSI_WAIT_FOR_VER_RESPONSE",
192                 "HVSI_WAIT_FOR_VER_QUERY",
193                 "HVSI_OPEN",
194                 "HVSI_WAIT_FOR_MCTRL_RESPONSE",
195                 "HVSI_FSP_DIED",
196         };
197         const char *name = (hp->state < ARRAY_SIZE(state_names))
198                 ? state_names[hp->state] : "UNKNOWN";
199
200         pr_debug("hvsi%i: state = %s\n", hp->index, name);
201 #endif /* DEBUG */
202 }
203
204 static inline void __set_state(struct hvsi_struct *hp, int state)
205 {
206         hp->state = state;
207         print_state(hp);
208         wake_up_all(&hp->stateq);
209 }
210
211 static inline void set_state(struct hvsi_struct *hp, int state)
212 {
213         unsigned long flags;
214
215         spin_lock_irqsave(&hp->lock, flags);
216         __set_state(hp, state);
217         spin_unlock_irqrestore(&hp->lock, flags);
218 }
219
220 static inline int len_packet(const uint8_t *packet)
221 {
222         return (int)((struct hvsi_header *)packet)->len;
223 }
224
225 static inline int is_header(const uint8_t *packet)
226 {
227         struct hvsi_header *header = (struct hvsi_header *)packet;
228         return header->type >= VS_QUERY_RESPONSE_PACKET_HEADER;
229 }
230
231 static inline int got_packet(const struct hvsi_struct *hp, uint8_t *packet)
232 {
233         if (hp->inbuf_end < packet + sizeof(struct hvsi_header))
234                 return 0; /* don't even have the packet header */
235
236         if (hp->inbuf_end < (packet + len_packet(packet)))
237                 return 0; /* don't have the rest of the packet */
238
239         return 1;
240 }
241
242 /* shift remaining bytes in packetbuf down */
243 static void compact_inbuf(struct hvsi_struct *hp, uint8_t *read_to)
244 {
245         int remaining = (int)(hp->inbuf_end - read_to);
246
247         pr_debug("%s: %i chars remain\n", __func__, remaining);
248
249         if (read_to != hp->inbuf)
250                 memmove(hp->inbuf, read_to, remaining);
251
252         hp->inbuf_end = hp->inbuf + remaining;
253 }
254
255 #ifdef DEBUG
256 #define dbg_dump_packet(packet) dump_packet(packet)
257 #define dbg_dump_hex(data, len) dump_hex(data, len)
258 #else
259 #define dbg_dump_packet(packet) do { } while (0)
260 #define dbg_dump_hex(data, len) do { } while (0)
261 #endif
262
263 static void dump_hex(const uint8_t *data, int len)
264 {
265         int i;
266
267         printk("    ");
268         for (i=0; i < len; i++)
269                 printk("%.2x", data[i]);
270
271         printk("\n    ");
272         for (i=0; i < len; i++) {
273                 if (isprint(data[i]))
274                         printk("%c", data[i]);
275                 else
276                         printk(".");
277         }
278         printk("\n");
279 }
280
281 static void dump_packet(uint8_t *packet)
282 {
283         struct hvsi_header *header = (struct hvsi_header *)packet;
284
285         printk("type 0x%x, len %i, seqno %i:\n", header->type, header->len,
286                         header->seqno);
287
288         dump_hex(packet, header->len);
289 }
290
291 static int hvsi_read(struct hvsi_struct *hp, char *buf, int count)
292 {
293         unsigned long got;
294
295         got = hvc_get_chars(hp->vtermno, buf, count);
296
297         return got;
298 }
299
300 static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet,
301         struct tty_struct **to_hangup, struct hvsi_struct **to_handshake)
302 {
303         struct hvsi_control *header = (struct hvsi_control *)packet;
304
305         switch (header->verb) {
306                 case VSV_MODEM_CTL_UPDATE:
307                         if ((header->word & HVSI_TSCD) == 0) {
308                                 /* CD went away; no more connection */
309                                 pr_debug("hvsi%i: CD dropped\n", hp->index);
310                                 hp->mctrl &= TIOCM_CD;
311                                 /* If userland hasn't done an open(2) yet, hp->tty is NULL. */
312                                 if (hp->tty && !(hp->tty->flags & CLOCAL))
313                                         *to_hangup = hp->tty;
314                         }
315                         break;
316                 case VSV_CLOSE_PROTOCOL:
317                         pr_debug("hvsi%i: service processor came back\n", hp->index);
318                         if (hp->state != HVSI_CLOSED) {
319                                 *to_handshake = hp;
320                         }
321                         break;
322                 default:
323                         printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ",
324                                 hp->index);
325                         dump_packet(packet);
326                         break;
327         }
328 }
329
330 static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet)
331 {
332         struct hvsi_query_response *resp = (struct hvsi_query_response *)packet;
333
334         switch (hp->state) {
335                 case HVSI_WAIT_FOR_VER_RESPONSE:
336                         __set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
337                         break;
338                 case HVSI_WAIT_FOR_MCTRL_RESPONSE:
339                         hp->mctrl = 0;
340                         if (resp->u.mctrl_word & HVSI_TSDTR)
341                                 hp->mctrl |= TIOCM_DTR;
342                         if (resp->u.mctrl_word & HVSI_TSCD)
343                                 hp->mctrl |= TIOCM_CD;
344                         __set_state(hp, HVSI_OPEN);
345                         break;
346                 default:
347                         printk(KERN_ERR "hvsi%i: unexpected query response: ", hp->index);
348                         dump_packet(packet);
349                         break;
350         }
351 }
352
353 /* respond to service processor's version query */
354 static int hvsi_version_respond(struct hvsi_struct *hp, uint16_t query_seqno)
355 {
356         struct hvsi_query_response packet __ALIGNED__;
357         int wrote;
358
359         packet.type = VS_QUERY_RESPONSE_PACKET_HEADER;
360         packet.len = sizeof(struct hvsi_query_response);
361         packet.seqno = atomic_inc_return(&hp->seqno);
362         packet.verb = VSV_SEND_VERSION_NUMBER;
363         packet.u.version = HVSI_VERSION;
364         packet.query_seqno = query_seqno+1;
365
366         pr_debug("%s: sending %i bytes\n", __func__, packet.len);
367         dbg_dump_hex((uint8_t*)&packet, packet.len);
368
369         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
370         if (wrote != packet.len) {
371                 printk(KERN_ERR "hvsi%i: couldn't send query response!\n",
372                         hp->index);
373                 return -EIO;
374         }
375
376         return 0;
377 }
378
379 static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet)
380 {
381         struct hvsi_query *query = (struct hvsi_query *)packet;
382
383         switch (hp->state) {
384                 case HVSI_WAIT_FOR_VER_QUERY:
385                         hvsi_version_respond(hp, query->seqno);
386                         __set_state(hp, HVSI_OPEN);
387                         break;
388                 default:
389                         printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index);
390                         dump_packet(packet);
391                         break;
392         }
393 }
394
395 static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len)
396 {
397         int i;
398
399         for (i=0; i < len; i++) {
400                 char c = buf[i];
401 #ifdef CONFIG_MAGIC_SYSRQ
402                 if (c == '\0') {
403                         hp->sysrq = 1;
404                         continue;
405                 } else if (hp->sysrq) {
406                         handle_sysrq(c, hp->tty);
407                         hp->sysrq = 0;
408                         continue;
409                 }
410 #endif /* CONFIG_MAGIC_SYSRQ */
411                 tty_insert_flip_char(hp->tty, c, 0);
412         }
413 }
414
415 /*
416  * We could get 252 bytes of data at once here. But the tty layer only
417  * throttles us at TTY_THRESHOLD_THROTTLE (128) bytes, so we could overflow
418  * it. Accordingly we won't send more than 128 bytes at a time to the flip
419  * buffer, which will give the tty buffer a chance to throttle us. Should the
420  * value of TTY_THRESHOLD_THROTTLE change in n_tty.c, this code should be
421  * revisited.
422  */
423 #define TTY_THRESHOLD_THROTTLE 128
424 static struct tty_struct *hvsi_recv_data(struct hvsi_struct *hp,
425                 const uint8_t *packet)
426 {
427         const struct hvsi_header *header = (const struct hvsi_header *)packet;
428         const uint8_t *data = packet + sizeof(struct hvsi_header);
429         int datalen = header->len - sizeof(struct hvsi_header);
430         int overflow = datalen - TTY_THRESHOLD_THROTTLE;
431
432         pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data);
433
434         if (datalen == 0)
435                 return NULL;
436
437         if (overflow > 0) {
438                 pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __func__);
439                 datalen = TTY_THRESHOLD_THROTTLE;
440         }
441
442         hvsi_insert_chars(hp, data, datalen);
443
444         if (overflow > 0) {
445                 /*
446                  * we still have more data to deliver, so we need to save off the
447                  * overflow and send it later
448                  */
449                 pr_debug("%s: deferring overflow\n", __func__);
450                 memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow);
451                 hp->n_throttle = overflow;
452         }
453
454         return hp->tty;
455 }
456
457 /*
458  * Returns true/false indicating data successfully read from hypervisor.
459  * Used both to get packets for tty connections and to advance the state
460  * machine during console handshaking (in which case tty = NULL and we ignore
461  * incoming data).
462  */
463 static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip,
464                 struct tty_struct **hangup, struct hvsi_struct **handshake)
465 {
466         uint8_t *packet = hp->inbuf;
467         int chunklen;
468
469         *flip = NULL;
470         *hangup = NULL;
471         *handshake = NULL;
472
473         chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
474         if (chunklen == 0) {
475                 pr_debug("%s: 0-length read\n", __func__);
476                 return 0;
477         }
478
479         pr_debug("%s: got %i bytes\n", __func__, chunklen);
480         dbg_dump_hex(hp->inbuf_end, chunklen);
481
482         hp->inbuf_end += chunklen;
483
484         /* handle all completed packets */
485         while ((packet < hp->inbuf_end) && got_packet(hp, packet)) {
486                 struct hvsi_header *header = (struct hvsi_header *)packet;
487
488                 if (!is_header(packet)) {
489                         printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index);
490                         /* skip bytes until we find a header or run out of data */
491                         while ((packet < hp->inbuf_end) && (!is_header(packet)))
492                                 packet++;
493                         continue;
494                 }
495
496                 pr_debug("%s: handling %i-byte packet\n", __func__,
497                                 len_packet(packet));
498                 dbg_dump_packet(packet);
499
500                 switch (header->type) {
501                         case VS_DATA_PACKET_HEADER:
502                                 if (!is_open(hp))
503                                         break;
504                                 if (hp->tty == NULL)
505                                         break; /* no tty buffer to put data in */
506                                 *flip = hvsi_recv_data(hp, packet);
507                                 break;
508                         case VS_CONTROL_PACKET_HEADER:
509                                 hvsi_recv_control(hp, packet, hangup, handshake);
510                                 break;
511                         case VS_QUERY_RESPONSE_PACKET_HEADER:
512                                 hvsi_recv_response(hp, packet);
513                                 break;
514                         case VS_QUERY_PACKET_HEADER:
515                                 hvsi_recv_query(hp, packet);
516                                 break;
517                         default:
518                                 printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
519                                                 hp->index, header->type);
520                                 dump_packet(packet);
521                                 break;
522                 }
523
524                 packet += len_packet(packet);
525
526                 if (*hangup || *handshake) {
527                         pr_debug("%s: hangup or handshake\n", __func__);
528                         /*
529                          * we need to send the hangup now before receiving any more data.
530                          * If we get "data, hangup, data", we can't deliver the second
531                          * data before the hangup.
532                          */
533                         break;
534                 }
535         }
536
537         compact_inbuf(hp, packet);
538
539         return 1;
540 }
541
542 static void hvsi_send_overflow(struct hvsi_struct *hp)
543 {
544         pr_debug("%s: delivering %i bytes overflow\n", __func__,
545                         hp->n_throttle);
546
547         hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);
548         hp->n_throttle = 0;
549 }
550
551 /*
552  * must get all pending data because we only get an irq on empty->non-empty
553  * transition
554  */
555 static irqreturn_t hvsi_interrupt(int irq, void *arg)
556 {
557         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
558         struct tty_struct *flip;
559         struct tty_struct *hangup;
560         struct hvsi_struct *handshake;
561         unsigned long flags;
562         int again = 1;
563
564         pr_debug("%s\n", __func__);
565
566         while (again) {
567                 spin_lock_irqsave(&hp->lock, flags);
568                 again = hvsi_load_chunk(hp, &flip, &hangup, &handshake);
569                 spin_unlock_irqrestore(&hp->lock, flags);
570
571                 /*
572                  * we have to call tty_flip_buffer_push() and tty_hangup() outside our
573                  * spinlock. But we also have to keep going until we've read all the
574                  * available data.
575                  */
576
577                 if (flip) {
578                         /* there was data put in the tty flip buffer */
579                         tty_flip_buffer_push(flip);
580                         flip = NULL;
581                 }
582
583                 if (hangup) {
584                         tty_hangup(hangup);
585                 }
586
587                 if (handshake) {
588                         pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
589                         schedule_work(&handshake->handshaker);
590                 }
591         }
592
593         spin_lock_irqsave(&hp->lock, flags);
594         if (hp->tty && hp->n_throttle
595                         && (!test_bit(TTY_THROTTLED, &hp->tty->flags))) {
596                 /* we weren't hung up and we weren't throttled, so we can deliver the
597                  * rest now */
598                 flip = hp->tty;
599                 hvsi_send_overflow(hp);
600         }
601         spin_unlock_irqrestore(&hp->lock, flags);
602
603         if (flip) {
604                 tty_flip_buffer_push(flip);
605         }
606
607         return IRQ_HANDLED;
608 }
609
610 /* for boot console, before the irq handler is running */
611 static int __init poll_for_state(struct hvsi_struct *hp, int state)
612 {
613         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
614
615         for (;;) {
616                 hvsi_interrupt(hp->virq, (void *)hp); /* get pending data */
617
618                 if (hp->state == state)
619                         return 0;
620
621                 mdelay(5);
622                 if (time_after(jiffies, end_jiffies))
623                         return -EIO;
624         }
625 }
626
627 /* wait for irq handler to change our state */
628 static int wait_for_state(struct hvsi_struct *hp, int state)
629 {
630         int ret = 0;
631
632         if (!wait_event_timeout(hp->stateq, (hp->state == state), HVSI_TIMEOUT))
633                 ret = -EIO;
634
635         return ret;
636 }
637
638 static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
639 {
640         struct hvsi_query packet __ALIGNED__;
641         int wrote;
642
643         packet.type = VS_QUERY_PACKET_HEADER;
644         packet.len = sizeof(struct hvsi_query);
645         packet.seqno = atomic_inc_return(&hp->seqno);
646         packet.verb = verb;
647
648         pr_debug("%s: sending %i bytes\n", __func__, packet.len);
649         dbg_dump_hex((uint8_t*)&packet, packet.len);
650
651         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
652         if (wrote != packet.len) {
653                 printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
654                         wrote);
655                 return -EIO;
656         }
657
658         return 0;
659 }
660
661 static int hvsi_get_mctrl(struct hvsi_struct *hp)
662 {
663         int ret;
664
665         set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
666         hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
667
668         ret = hvsi_wait(hp, HVSI_OPEN);
669         if (ret < 0) {
670                 printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
671                 set_state(hp, HVSI_OPEN);
672                 return ret;
673         }
674
675         pr_debug("%s: mctrl 0x%x\n", __func__, hp->mctrl);
676
677         return 0;
678 }
679
680 /* note that we can only set DTR */
681 static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
682 {
683         struct hvsi_control packet __ALIGNED__;
684         int wrote;
685
686         packet.type = VS_CONTROL_PACKET_HEADER,
687         packet.seqno = atomic_inc_return(&hp->seqno);
688         packet.len = sizeof(struct hvsi_control);
689         packet.verb = VSV_SET_MODEM_CTL;
690         packet.mask = HVSI_TSDTR;
691
692         if (mctrl & TIOCM_DTR)
693                 packet.word = HVSI_TSDTR;
694
695         pr_debug("%s: sending %i bytes\n", __func__, packet.len);
696         dbg_dump_hex((uint8_t*)&packet, packet.len);
697
698         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
699         if (wrote != packet.len) {
700                 printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
701                 return -EIO;
702         }
703
704         return 0;
705 }
706
707 static void hvsi_drain_input(struct hvsi_struct *hp)
708 {
709         uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
710         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
711
712         while (time_before(end_jiffies, jiffies))
713                 if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
714                         break;
715 }
716
717 static int hvsi_handshake(struct hvsi_struct *hp)
718 {
719         int ret;
720
721         /*
722          * We could have a CLOSE or other data waiting for us before we even try
723          * to open; try to throw it all away so we don't get confused. (CLOSE
724          * is the first message sent up the pipe when the FSP comes online. We
725          * need to distinguish between "it came up a while ago and we're the first
726          * user" and "it was just reset before it saw our handshake packet".)
727          */
728         hvsi_drain_input(hp);
729
730         set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
731         ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
732         if (ret < 0) {
733                 printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
734                 return ret;
735         }
736
737         ret = hvsi_wait(hp, HVSI_OPEN);
738         if (ret < 0)
739                 return ret;
740
741         return 0;
742 }
743
744 static void hvsi_handshaker(struct work_struct *work)
745 {
746         struct hvsi_struct *hp =
747                 container_of(work, struct hvsi_struct, handshaker);
748
749         if (hvsi_handshake(hp) >= 0)
750                 return;
751
752         printk(KERN_ERR "hvsi%i: re-handshaking failed\n", hp->index);
753         if (is_console(hp)) {
754                 /*
755                  * ttys will re-attempt the handshake via hvsi_open, but
756                  * the console will not.
757                  */
758                 printk(KERN_ERR "hvsi%i: lost console!\n", hp->index);
759         }
760 }
761
762 static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
763 {
764         struct hvsi_data packet __ALIGNED__;
765         int ret;
766
767         BUG_ON(count > HVSI_MAX_OUTGOING_DATA);
768
769         packet.type = VS_DATA_PACKET_HEADER;
770         packet.seqno = atomic_inc_return(&hp->seqno);
771         packet.len = count + sizeof(struct hvsi_header);
772         memcpy(&packet.data, buf, count);
773
774         ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
775         if (ret == packet.len) {
776                 /* return the number of chars written, not the packet length */
777                 return count;
778         }
779         return ret; /* return any errors */
780 }
781
782 static void hvsi_close_protocol(struct hvsi_struct *hp)
783 {
784         struct hvsi_control packet __ALIGNED__;
785
786         packet.type = VS_CONTROL_PACKET_HEADER;
787         packet.seqno = atomic_inc_return(&hp->seqno);
788         packet.len = 6;
789         packet.verb = VSV_CLOSE_PROTOCOL;
790
791         pr_debug("%s: sending %i bytes\n", __func__, packet.len);
792         dbg_dump_hex((uint8_t*)&packet, packet.len);
793
794         hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
795 }
796
797 static int hvsi_open(struct tty_struct *tty, struct file *filp)
798 {
799         struct hvsi_struct *hp;
800         unsigned long flags;
801         int line = tty->index;
802         int ret;
803
804         pr_debug("%s\n", __func__);
805
806         if (line < 0 || line >= hvsi_count)
807                 return -ENODEV;
808         hp = &hvsi_ports[line];
809
810         tty->driver_data = hp;
811
812         mb();
813         if (hp->state == HVSI_FSP_DIED)
814                 return -EIO;
815
816         spin_lock_irqsave(&hp->lock, flags);
817         hp->tty = tty;
818         hp->count++;
819         atomic_set(&hp->seqno, 0);
820         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
821         spin_unlock_irqrestore(&hp->lock, flags);
822
823         if (is_console(hp))
824                 return 0; /* this has already been handshaked as the console */
825
826         ret = hvsi_handshake(hp);
827         if (ret < 0) {
828                 printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
829                 return ret;
830         }
831
832         ret = hvsi_get_mctrl(hp);
833         if (ret < 0) {
834                 printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name);
835                 return ret;
836         }
837
838         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
839         if (ret < 0) {
840                 printk(KERN_ERR "%s: couldn't set DTR\n", tty->name);
841                 return ret;
842         }
843
844         return 0;
845 }
846
847 /* wait for hvsi_write_worker to empty hp->outbuf */
848 static void hvsi_flush_output(struct hvsi_struct *hp)
849 {
850         wait_event_timeout(hp->emptyq, (hp->n_outbuf <= 0), HVSI_TIMEOUT);
851
852         /* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */
853         cancel_delayed_work(&hp->writer);
854         flush_scheduled_work();
855
856         /*
857          * it's also possible that our timeout expired and hvsi_write_worker
858          * didn't manage to push outbuf. poof.
859          */
860         hp->n_outbuf = 0;
861 }
862
863 static void hvsi_close(struct tty_struct *tty, struct file *filp)
864 {
865         struct hvsi_struct *hp = tty->driver_data;
866         unsigned long flags;
867
868         pr_debug("%s\n", __func__);
869
870         if (tty_hung_up_p(filp))
871                 return;
872
873         spin_lock_irqsave(&hp->lock, flags);
874
875         if (--hp->count == 0) {
876                 hp->tty = NULL;
877                 hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
878
879                 /* only close down connection if it is not the console */
880                 if (!is_console(hp)) {
881                         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */
882                         __set_state(hp, HVSI_CLOSED);
883                         /*
884                          * any data delivered to the tty layer after this will be
885                          * discarded (except for XON/XOFF)
886                          */
887                         tty->closing = 1;
888
889                         spin_unlock_irqrestore(&hp->lock, flags);
890
891                         /* let any existing irq handlers finish. no more will start. */
892                         synchronize_irq(hp->virq);
893
894                         /* hvsi_write_worker will re-schedule until outbuf is empty. */
895                         hvsi_flush_output(hp);
896
897                         /* tell FSP to stop sending data */
898                         hvsi_close_protocol(hp);
899
900                         /*
901                          * drain anything FSP is still in the middle of sending, and let
902                          * hvsi_handshake drain the rest on the next open.
903                          */
904                         hvsi_drain_input(hp);
905
906                         spin_lock_irqsave(&hp->lock, flags);
907                 }
908         } else if (hp->count < 0)
909                 printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n",
910                        hp - hvsi_ports, hp->count);
911
912         spin_unlock_irqrestore(&hp->lock, flags);
913 }
914
915 static void hvsi_hangup(struct tty_struct *tty)
916 {
917         struct hvsi_struct *hp = tty->driver_data;
918         unsigned long flags;
919
920         pr_debug("%s\n", __func__);
921
922         spin_lock_irqsave(&hp->lock, flags);
923
924         hp->count = 0;
925         hp->n_outbuf = 0;
926         hp->tty = NULL;
927
928         spin_unlock_irqrestore(&hp->lock, flags);
929 }
930
931 /* called with hp->lock held */
932 static void hvsi_push(struct hvsi_struct *hp)
933 {
934         int n;
935
936         if (hp->n_outbuf <= 0)
937                 return;
938
939         n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf);
940         if (n > 0) {
941                 /* success */
942                 pr_debug("%s: wrote %i chars\n", __func__, n);
943                 hp->n_outbuf = 0;
944         } else if (n == -EIO) {
945                 __set_state(hp, HVSI_FSP_DIED);
946                 printk(KERN_ERR "hvsi%i: service processor died\n", hp->index);
947         }
948 }
949
950 /* hvsi_write_worker will keep rescheduling itself until outbuf is empty */
951 static void hvsi_write_worker(struct work_struct *work)
952 {
953         struct hvsi_struct *hp =
954                 container_of(work, struct hvsi_struct, writer.work);
955         unsigned long flags;
956 #ifdef DEBUG
957         static long start_j = 0;
958
959         if (start_j == 0)
960                 start_j = jiffies;
961 #endif /* DEBUG */
962
963         spin_lock_irqsave(&hp->lock, flags);
964
965         pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
966
967         if (!is_open(hp)) {
968                 /*
969                  * We could have a non-open connection if the service processor died
970                  * while we were busily scheduling ourselves. In that case, it could
971                  * be minutes before the service processor comes back, so only try
972                  * again once a second.
973                  */
974                 schedule_delayed_work(&hp->writer, HZ);
975                 goto out;
976         }
977
978         hvsi_push(hp);
979         if (hp->n_outbuf > 0)
980                 schedule_delayed_work(&hp->writer, 10);
981         else {
982 #ifdef DEBUG
983                 pr_debug("%s: outbuf emptied after %li jiffies\n", __func__,
984                                 jiffies - start_j);
985                 start_j = 0;
986 #endif /* DEBUG */
987                 wake_up_all(&hp->emptyq);
988                 tty_wakeup(hp->tty);
989         }
990
991 out:
992         spin_unlock_irqrestore(&hp->lock, flags);
993 }
994
995 static int hvsi_write_room(struct tty_struct *tty)
996 {
997         struct hvsi_struct *hp = tty->driver_data;
998
999         return N_OUTBUF - hp->n_outbuf;
1000 }
1001
1002 static int hvsi_chars_in_buffer(struct tty_struct *tty)
1003 {
1004         struct hvsi_struct *hp = tty->driver_data;
1005
1006         return hp->n_outbuf;
1007 }
1008
1009 static int hvsi_write(struct tty_struct *tty,
1010                      const unsigned char *buf, int count)
1011 {
1012         struct hvsi_struct *hp = tty->driver_data;
1013         const char *source = buf;
1014         unsigned long flags;
1015         int total = 0;
1016         int origcount = count;
1017
1018         spin_lock_irqsave(&hp->lock, flags);
1019
1020         pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
1021
1022         if (!is_open(hp)) {
1023                 /* we're either closing or not yet open; don't accept data */
1024                 pr_debug("%s: not open\n", __func__);
1025                 goto out;
1026         }
1027
1028         /*
1029          * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf
1030          * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls
1031          * will see there is no room in outbuf and return.
1032          */
1033         while ((count > 0) && (hvsi_write_room(hp->tty) > 0)) {
1034                 int chunksize = min(count, hvsi_write_room(hp->tty));
1035
1036                 BUG_ON(hp->n_outbuf < 0);
1037                 memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
1038                 hp->n_outbuf += chunksize;
1039
1040                 total += chunksize;
1041                 source += chunksize;
1042                 count -= chunksize;
1043                 hvsi_push(hp);
1044         }
1045
1046         if (hp->n_outbuf > 0) {
1047                 /*
1048                  * we weren't able to write it all to the hypervisor.
1049                  * schedule another push attempt.
1050                  */
1051                 schedule_delayed_work(&hp->writer, 10);
1052         }
1053
1054 out:
1055         spin_unlock_irqrestore(&hp->lock, flags);
1056
1057         if (total != origcount)
1058                 pr_debug("%s: wanted %i, only wrote %i\n", __func__, origcount,
1059                         total);
1060
1061         return total;
1062 }
1063
1064 /*
1065  * I have never seen throttle or unthrottle called, so this little throttle
1066  * buffering scheme may or may not work.
1067  */
1068 static void hvsi_throttle(struct tty_struct *tty)
1069 {
1070         struct hvsi_struct *hp = tty->driver_data;
1071
1072         pr_debug("%s\n", __func__);
1073
1074         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE);
1075 }
1076
1077 static void hvsi_unthrottle(struct tty_struct *tty)
1078 {
1079         struct hvsi_struct *hp = tty->driver_data;
1080         unsigned long flags;
1081         int shouldflip = 0;
1082
1083         pr_debug("%s\n", __func__);
1084
1085         spin_lock_irqsave(&hp->lock, flags);
1086         if (hp->n_throttle) {
1087                 hvsi_send_overflow(hp);
1088                 shouldflip = 1;
1089         }
1090         spin_unlock_irqrestore(&hp->lock, flags);
1091
1092         if (shouldflip)
1093                 tty_flip_buffer_push(hp->tty);
1094
1095         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
1096 }
1097
1098 static int hvsi_tiocmget(struct tty_struct *tty, struct file *file)
1099 {
1100         struct hvsi_struct *hp = tty->driver_data;
1101
1102         hvsi_get_mctrl(hp);
1103         return hp->mctrl;
1104 }
1105
1106 static int hvsi_tiocmset(struct tty_struct *tty, struct file *file,
1107                 unsigned int set, unsigned int clear)
1108 {
1109         struct hvsi_struct *hp = tty->driver_data;
1110         unsigned long flags;
1111         uint16_t new_mctrl;
1112
1113         /* we can only alter DTR */
1114         clear &= TIOCM_DTR;
1115         set &= TIOCM_DTR;
1116
1117         spin_lock_irqsave(&hp->lock, flags);
1118
1119         new_mctrl = (hp->mctrl & ~clear) | set;
1120
1121         if (hp->mctrl != new_mctrl) {
1122                 hvsi_set_mctrl(hp, new_mctrl);
1123                 hp->mctrl = new_mctrl;
1124         }
1125         spin_unlock_irqrestore(&hp->lock, flags);
1126
1127         return 0;
1128 }
1129
1130
1131 static const struct tty_operations hvsi_ops = {
1132         .open = hvsi_open,
1133         .close = hvsi_close,
1134         .write = hvsi_write,
1135         .hangup = hvsi_hangup,
1136         .write_room = hvsi_write_room,
1137         .chars_in_buffer = hvsi_chars_in_buffer,
1138         .throttle = hvsi_throttle,
1139         .unthrottle = hvsi_unthrottle,
1140         .tiocmget = hvsi_tiocmget,
1141         .tiocmset = hvsi_tiocmset,
1142 };
1143
1144 static int __init hvsi_init(void)
1145 {
1146         int i;
1147
1148         hvsi_driver = alloc_tty_driver(hvsi_count);
1149         if (!hvsi_driver)
1150                 return -ENOMEM;
1151
1152         hvsi_driver->owner = THIS_MODULE;
1153         hvsi_driver->driver_name = "hvsi";
1154         hvsi_driver->name = "hvsi";
1155         hvsi_driver->major = HVSI_MAJOR;
1156         hvsi_driver->minor_start = HVSI_MINOR;
1157         hvsi_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1158         hvsi_driver->init_termios = tty_std_termios;
1159         hvsi_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
1160         hvsi_driver->init_termios.c_ispeed = 9600;
1161         hvsi_driver->init_termios.c_ospeed = 9600;
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;
1232         int ret;
1233
1234         if (console->index < 0 || console->index >= hvsi_count)
1235                 return -1;
1236         hp = &hvsi_ports[console->index];
1237
1238         /* give the FSP a chance to change the baud rate when we re-open */
1239         hvsi_close_protocol(hp);
1240
1241         ret = hvsi_handshake(hp);
1242         if (ret < 0)
1243                 return ret;
1244
1245         ret = hvsi_get_mctrl(hp);
1246         if (ret < 0)
1247                 return ret;
1248
1249         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
1250         if (ret < 0)
1251                 return ret;
1252
1253         hp->flags |= HVSI_CONSOLE;
1254
1255         return 0;
1256 }
1257
1258 static struct console hvsi_con_driver = {
1259         .name           = "hvsi",
1260         .write          = hvsi_console_print,
1261         .device         = hvsi_console_device,
1262         .setup          = hvsi_console_setup,
1263         .flags          = CON_PRINTBUFFER,
1264         .index          = -1,
1265 };
1266
1267 static int __init hvsi_console_init(void)
1268 {
1269         struct device_node *vty;
1270
1271         hvsi_wait = poll_for_state; /* no irqs yet; must poll */
1272
1273         /* search device tree for vty nodes */
1274         for (vty = of_find_compatible_node(NULL, "serial", "hvterm-protocol");
1275                         vty != NULL;
1276                         vty = of_find_compatible_node(vty, "serial", "hvterm-protocol")) {
1277                 struct hvsi_struct *hp;
1278                 const uint32_t *vtermno, *irq;
1279
1280                 vtermno = of_get_property(vty, "reg", NULL);
1281                 irq = of_get_property(vty, "interrupts", NULL);
1282                 if (!vtermno || !irq)
1283                         continue;
1284
1285                 if (hvsi_count >= MAX_NR_HVSI_CONSOLES) {
1286                         of_node_put(vty);
1287                         break;
1288                 }
1289
1290                 hp = &hvsi_ports[hvsi_count];
1291                 INIT_DELAYED_WORK(&hp->writer, hvsi_write_worker);
1292                 INIT_WORK(&hp->handshaker, hvsi_handshaker);
1293                 init_waitqueue_head(&hp->emptyq);
1294                 init_waitqueue_head(&hp->stateq);
1295                 spin_lock_init(&hp->lock);
1296                 hp->index = hvsi_count;
1297                 hp->inbuf_end = hp->inbuf;
1298                 hp->state = HVSI_CLOSED;
1299                 hp->vtermno = *vtermno;
1300                 hp->virq = irq_create_mapping(NULL, irq[0]);
1301                 if (hp->virq == NO_IRQ) {
1302                         printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
1303                                 __func__, irq[0]);
1304                         continue;
1305                 }
1306
1307                 hvsi_count++;
1308         }
1309
1310         if (hvsi_count)
1311                 register_console(&hvsi_con_driver);
1312         return 0;
1313 }
1314 console_initcall(hvsi_console_init);