readahead: combine file_ra_state.prev_index/prev_offset into prev_pos
[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/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         unsigned 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 = state_names[hp->state];
198
199         if (hp->state > ARRAY_SIZE(state_names))
200                 name = "UNKNOWN";
201
202         pr_debug("hvsi%i: state = %s\n", hp->index, name);
203 #endif /* DEBUG */
204 }
205
206 static inline void __set_state(struct hvsi_struct *hp, int state)
207 {
208         hp->state = state;
209         print_state(hp);
210         wake_up_all(&hp->stateq);
211 }
212
213 static inline void set_state(struct hvsi_struct *hp, int state)
214 {
215         unsigned long flags;
216
217         spin_lock_irqsave(&hp->lock, flags);
218         __set_state(hp, state);
219         spin_unlock_irqrestore(&hp->lock, flags);
220 }
221
222 static inline int len_packet(const uint8_t *packet)
223 {
224         return (int)((struct hvsi_header *)packet)->len;
225 }
226
227 static inline int is_header(const uint8_t *packet)
228 {
229         struct hvsi_header *header = (struct hvsi_header *)packet;
230         return header->type >= VS_QUERY_RESPONSE_PACKET_HEADER;
231 }
232
233 static inline int got_packet(const struct hvsi_struct *hp, uint8_t *packet)
234 {
235         if (hp->inbuf_end < packet + sizeof(struct hvsi_header))
236                 return 0; /* don't even have the packet header */
237
238         if (hp->inbuf_end < (packet + len_packet(packet)))
239                 return 0; /* don't have the rest of the packet */
240
241         return 1;
242 }
243
244 /* shift remaining bytes in packetbuf down */
245 static void compact_inbuf(struct hvsi_struct *hp, uint8_t *read_to)
246 {
247         int remaining = (int)(hp->inbuf_end - read_to);
248
249         pr_debug("%s: %i chars remain\n", __FUNCTION__, remaining);
250
251         if (read_to != hp->inbuf)
252                 memmove(hp->inbuf, read_to, remaining);
253
254         hp->inbuf_end = hp->inbuf + remaining;
255 }
256
257 #ifdef DEBUG
258 #define dbg_dump_packet(packet) dump_packet(packet)
259 #define dbg_dump_hex(data, len) dump_hex(data, len)
260 #else
261 #define dbg_dump_packet(packet) do { } while (0)
262 #define dbg_dump_hex(data, len) do { } while (0)
263 #endif
264
265 static void dump_hex(const uint8_t *data, int len)
266 {
267         int i;
268
269         printk("    ");
270         for (i=0; i < len; i++)
271                 printk("%.2x", data[i]);
272
273         printk("\n    ");
274         for (i=0; i < len; i++) {
275                 if (isprint(data[i]))
276                         printk("%c", data[i]);
277                 else
278                         printk(".");
279         }
280         printk("\n");
281 }
282
283 static void dump_packet(uint8_t *packet)
284 {
285         struct hvsi_header *header = (struct hvsi_header *)packet;
286
287         printk("type 0x%x, len %i, seqno %i:\n", header->type, header->len,
288                         header->seqno);
289
290         dump_hex(packet, header->len);
291 }
292
293 static int hvsi_read(struct hvsi_struct *hp, char *buf, int count)
294 {
295         unsigned long got;
296
297         got = hvc_get_chars(hp->vtermno, buf, count);
298
299         return got;
300 }
301
302 static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet,
303         struct tty_struct **to_hangup, struct hvsi_struct **to_handshake)
304 {
305         struct hvsi_control *header = (struct hvsi_control *)packet;
306
307         switch (header->verb) {
308                 case VSV_MODEM_CTL_UPDATE:
309                         if ((header->word & HVSI_TSCD) == 0) {
310                                 /* CD went away; no more connection */
311                                 pr_debug("hvsi%i: CD dropped\n", hp->index);
312                                 hp->mctrl &= TIOCM_CD;
313                                 /* If userland hasn't done an open(2) yet, hp->tty is NULL. */
314                                 if (hp->tty && !(hp->tty->flags & CLOCAL))
315                                         *to_hangup = hp->tty;
316                         }
317                         break;
318                 case VSV_CLOSE_PROTOCOL:
319                         pr_debug("hvsi%i: service processor came back\n", hp->index);
320                         if (hp->state != HVSI_CLOSED) {
321                                 *to_handshake = hp;
322                         }
323                         break;
324                 default:
325                         printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ",
326                                 hp->index);
327                         dump_packet(packet);
328                         break;
329         }
330 }
331
332 static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet)
333 {
334         struct hvsi_query_response *resp = (struct hvsi_query_response *)packet;
335
336         switch (hp->state) {
337                 case HVSI_WAIT_FOR_VER_RESPONSE:
338                         __set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
339                         break;
340                 case HVSI_WAIT_FOR_MCTRL_RESPONSE:
341                         hp->mctrl = 0;
342                         if (resp->u.mctrl_word & HVSI_TSDTR)
343                                 hp->mctrl |= TIOCM_DTR;
344                         if (resp->u.mctrl_word & HVSI_TSCD)
345                                 hp->mctrl |= TIOCM_CD;
346                         __set_state(hp, HVSI_OPEN);
347                         break;
348                 default:
349                         printk(KERN_ERR "hvsi%i: unexpected query response: ", hp->index);
350                         dump_packet(packet);
351                         break;
352         }
353 }
354
355 /* respond to service processor's version query */
356 static int hvsi_version_respond(struct hvsi_struct *hp, uint16_t query_seqno)
357 {
358         struct hvsi_query_response packet __ALIGNED__;
359         int wrote;
360
361         packet.type = VS_QUERY_RESPONSE_PACKET_HEADER;
362         packet.len = sizeof(struct hvsi_query_response);
363         packet.seqno = atomic_inc_return(&hp->seqno);
364         packet.verb = VSV_SEND_VERSION_NUMBER;
365         packet.u.version = HVSI_VERSION;
366         packet.query_seqno = query_seqno+1;
367
368         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
369         dbg_dump_hex((uint8_t*)&packet, packet.len);
370
371         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
372         if (wrote != packet.len) {
373                 printk(KERN_ERR "hvsi%i: couldn't send query response!\n",
374                         hp->index);
375                 return -EIO;
376         }
377
378         return 0;
379 }
380
381 static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet)
382 {
383         struct hvsi_query *query = (struct hvsi_query *)packet;
384
385         switch (hp->state) {
386                 case HVSI_WAIT_FOR_VER_QUERY:
387                         hvsi_version_respond(hp, query->seqno);
388                         __set_state(hp, HVSI_OPEN);
389                         break;
390                 default:
391                         printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index);
392                         dump_packet(packet);
393                         break;
394         }
395 }
396
397 static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len)
398 {
399         int i;
400
401         for (i=0; i < len; i++) {
402                 char c = buf[i];
403 #ifdef CONFIG_MAGIC_SYSRQ
404                 if (c == '\0') {
405                         hp->sysrq = 1;
406                         continue;
407                 } else if (hp->sysrq) {
408                         handle_sysrq(c, hp->tty);
409                         hp->sysrq = 0;
410                         continue;
411                 }
412 #endif /* CONFIG_MAGIC_SYSRQ */
413                 tty_insert_flip_char(hp->tty, c, 0);
414         }
415 }
416
417 /*
418  * We could get 252 bytes of data at once here. But the tty layer only
419  * throttles us at TTY_THRESHOLD_THROTTLE (128) bytes, so we could overflow
420  * it. Accordingly we won't send more than 128 bytes at a time to the flip
421  * buffer, which will give the tty buffer a chance to throttle us. Should the
422  * value of TTY_THRESHOLD_THROTTLE change in n_tty.c, this code should be
423  * revisited.
424  */
425 #define TTY_THRESHOLD_THROTTLE 128
426 static struct tty_struct *hvsi_recv_data(struct hvsi_struct *hp,
427                 const uint8_t *packet)
428 {
429         const struct hvsi_header *header = (const struct hvsi_header *)packet;
430         const uint8_t *data = packet + sizeof(struct hvsi_header);
431         int datalen = header->len - sizeof(struct hvsi_header);
432         int overflow = datalen - TTY_THRESHOLD_THROTTLE;
433
434         pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data);
435
436         if (datalen == 0)
437                 return NULL;
438
439         if (overflow > 0) {
440                 pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __FUNCTION__);
441                 datalen = TTY_THRESHOLD_THROTTLE;
442         }
443
444         hvsi_insert_chars(hp, data, datalen);
445
446         if (overflow > 0) {
447                 /*
448                  * we still have more data to deliver, so we need to save off the
449                  * overflow and send it later
450                  */
451                 pr_debug("%s: deferring overflow\n", __FUNCTION__);
452                 memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow);
453                 hp->n_throttle = overflow;
454         }
455
456         return hp->tty;
457 }
458
459 /*
460  * Returns true/false indicating data successfully read from hypervisor.
461  * Used both to get packets for tty connections and to advance the state
462  * machine during console handshaking (in which case tty = NULL and we ignore
463  * incoming data).
464  */
465 static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip,
466                 struct tty_struct **hangup, struct hvsi_struct **handshake)
467 {
468         uint8_t *packet = hp->inbuf;
469         int chunklen;
470
471         *flip = NULL;
472         *hangup = NULL;
473         *handshake = NULL;
474
475         chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
476         if (chunklen == 0) {
477                 pr_debug("%s: 0-length read\n", __FUNCTION__);
478                 return 0;
479         }
480
481         pr_debug("%s: got %i bytes\n", __FUNCTION__, chunklen);
482         dbg_dump_hex(hp->inbuf_end, chunklen);
483
484         hp->inbuf_end += chunklen;
485
486         /* handle all completed packets */
487         while ((packet < hp->inbuf_end) && got_packet(hp, packet)) {
488                 struct hvsi_header *header = (struct hvsi_header *)packet;
489
490                 if (!is_header(packet)) {
491                         printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index);
492                         /* skip bytes until we find a header or run out of data */
493                         while ((packet < hp->inbuf_end) && (!is_header(packet)))
494                                 packet++;
495                         continue;
496                 }
497
498                 pr_debug("%s: handling %i-byte packet\n", __FUNCTION__,
499                                 len_packet(packet));
500                 dbg_dump_packet(packet);
501
502                 switch (header->type) {
503                         case VS_DATA_PACKET_HEADER:
504                                 if (!is_open(hp))
505                                         break;
506                                 if (hp->tty == NULL)
507                                         break; /* no tty buffer to put data in */
508                                 *flip = hvsi_recv_data(hp, packet);
509                                 break;
510                         case VS_CONTROL_PACKET_HEADER:
511                                 hvsi_recv_control(hp, packet, hangup, handshake);
512                                 break;
513                         case VS_QUERY_RESPONSE_PACKET_HEADER:
514                                 hvsi_recv_response(hp, packet);
515                                 break;
516                         case VS_QUERY_PACKET_HEADER:
517                                 hvsi_recv_query(hp, packet);
518                                 break;
519                         default:
520                                 printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
521                                                 hp->index, header->type);
522                                 dump_packet(packet);
523                                 break;
524                 }
525
526                 packet += len_packet(packet);
527
528                 if (*hangup || *handshake) {
529                         pr_debug("%s: hangup or handshake\n", __FUNCTION__);
530                         /*
531                          * we need to send the hangup now before receiving any more data.
532                          * If we get "data, hangup, data", we can't deliver the second
533                          * data before the hangup.
534                          */
535                         break;
536                 }
537         }
538
539         compact_inbuf(hp, packet);
540
541         return 1;
542 }
543
544 static void hvsi_send_overflow(struct hvsi_struct *hp)
545 {
546         pr_debug("%s: delivering %i bytes overflow\n", __FUNCTION__,
547                         hp->n_throttle);
548
549         hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);
550         hp->n_throttle = 0;
551 }
552
553 /*
554  * must get all pending data because we only get an irq on empty->non-empty
555  * transition
556  */
557 static irqreturn_t hvsi_interrupt(int irq, void *arg)
558 {
559         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
560         struct tty_struct *flip;
561         struct tty_struct *hangup;
562         struct hvsi_struct *handshake;
563         unsigned long flags;
564         int again = 1;
565
566         pr_debug("%s\n", __FUNCTION__);
567
568         while (again) {
569                 spin_lock_irqsave(&hp->lock, flags);
570                 again = hvsi_load_chunk(hp, &flip, &hangup, &handshake);
571                 spin_unlock_irqrestore(&hp->lock, flags);
572
573                 /*
574                  * we have to call tty_flip_buffer_push() and tty_hangup() outside our
575                  * spinlock. But we also have to keep going until we've read all the
576                  * available data.
577                  */
578
579                 if (flip) {
580                         /* there was data put in the tty flip buffer */
581                         tty_flip_buffer_push(flip);
582                         flip = NULL;
583                 }
584
585                 if (hangup) {
586                         tty_hangup(hangup);
587                 }
588
589                 if (handshake) {
590                         pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
591                         schedule_work(&handshake->handshaker);
592                 }
593         }
594
595         spin_lock_irqsave(&hp->lock, flags);
596         if (hp->tty && hp->n_throttle
597                         && (!test_bit(TTY_THROTTLED, &hp->tty->flags))) {
598                 /* we weren't hung up and we weren't throttled, so we can deliver the
599                  * rest now */
600                 flip = hp->tty;
601                 hvsi_send_overflow(hp);
602         }
603         spin_unlock_irqrestore(&hp->lock, flags);
604
605         if (flip) {
606                 tty_flip_buffer_push(flip);
607         }
608
609         return IRQ_HANDLED;
610 }
611
612 /* for boot console, before the irq handler is running */
613 static int __init poll_for_state(struct hvsi_struct *hp, int state)
614 {
615         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
616
617         for (;;) {
618                 hvsi_interrupt(hp->virq, (void *)hp); /* get pending data */
619
620                 if (hp->state == state)
621                         return 0;
622
623                 mdelay(5);
624                 if (time_after(jiffies, end_jiffies))
625                         return -EIO;
626         }
627 }
628
629 /* wait for irq handler to change our state */
630 static int wait_for_state(struct hvsi_struct *hp, int state)
631 {
632         int ret = 0;
633
634         if (!wait_event_timeout(hp->stateq, (hp->state == state), HVSI_TIMEOUT))
635                 ret = -EIO;
636
637         return ret;
638 }
639
640 static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
641 {
642         struct hvsi_query packet __ALIGNED__;
643         int wrote;
644
645         packet.type = VS_QUERY_PACKET_HEADER;
646         packet.len = sizeof(struct hvsi_query);
647         packet.seqno = atomic_inc_return(&hp->seqno);
648         packet.verb = verb;
649
650         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
651         dbg_dump_hex((uint8_t*)&packet, packet.len);
652
653         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
654         if (wrote != packet.len) {
655                 printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
656                         wrote);
657                 return -EIO;
658         }
659
660         return 0;
661 }
662
663 static int hvsi_get_mctrl(struct hvsi_struct *hp)
664 {
665         int ret;
666
667         set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
668         hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
669
670         ret = hvsi_wait(hp, HVSI_OPEN);
671         if (ret < 0) {
672                 printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
673                 set_state(hp, HVSI_OPEN);
674                 return ret;
675         }
676
677         pr_debug("%s: mctrl 0x%x\n", __FUNCTION__, hp->mctrl);
678
679         return 0;
680 }
681
682 /* note that we can only set DTR */
683 static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
684 {
685         struct hvsi_control packet __ALIGNED__;
686         int wrote;
687
688         packet.type = VS_CONTROL_PACKET_HEADER,
689         packet.seqno = atomic_inc_return(&hp->seqno);
690         packet.len = sizeof(struct hvsi_control);
691         packet.verb = VSV_SET_MODEM_CTL;
692         packet.mask = HVSI_TSDTR;
693
694         if (mctrl & TIOCM_DTR)
695                 packet.word = HVSI_TSDTR;
696
697         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
698         dbg_dump_hex((uint8_t*)&packet, packet.len);
699
700         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
701         if (wrote != packet.len) {
702                 printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
703                 return -EIO;
704         }
705
706         return 0;
707 }
708
709 static void hvsi_drain_input(struct hvsi_struct *hp)
710 {
711         uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
712         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
713
714         while (time_before(end_jiffies, jiffies))
715                 if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
716                         break;
717 }
718
719 static int hvsi_handshake(struct hvsi_struct *hp)
720 {
721         int ret;
722
723         /*
724          * We could have a CLOSE or other data waiting for us before we even try
725          * to open; try to throw it all away so we don't get confused. (CLOSE
726          * is the first message sent up the pipe when the FSP comes online. We
727          * need to distinguish between "it came up a while ago and we're the first
728          * user" and "it was just reset before it saw our handshake packet".)
729          */
730         hvsi_drain_input(hp);
731
732         set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
733         ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
734         if (ret < 0) {
735                 printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
736                 return ret;
737         }
738
739         ret = hvsi_wait(hp, HVSI_OPEN);
740         if (ret < 0)
741                 return ret;
742
743         return 0;
744 }
745
746 static void hvsi_handshaker(struct work_struct *work)
747 {
748         struct hvsi_struct *hp =
749                 container_of(work, struct hvsi_struct, handshaker);
750
751         if (hvsi_handshake(hp) >= 0)
752                 return;
753
754         printk(KERN_ERR "hvsi%i: re-handshaking failed\n", hp->index);
755         if (is_console(hp)) {
756                 /*
757                  * ttys will re-attempt the handshake via hvsi_open, but
758                  * the console will not.
759                  */
760                 printk(KERN_ERR "hvsi%i: lost console!\n", hp->index);
761         }
762 }
763
764 static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
765 {
766         struct hvsi_data packet __ALIGNED__;
767         int ret;
768
769         BUG_ON(count > HVSI_MAX_OUTGOING_DATA);
770
771         packet.type = VS_DATA_PACKET_HEADER;
772         packet.seqno = atomic_inc_return(&hp->seqno);
773         packet.len = count + sizeof(struct hvsi_header);
774         memcpy(&packet.data, buf, count);
775
776         ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
777         if (ret == packet.len) {
778                 /* return the number of chars written, not the packet length */
779                 return count;
780         }
781         return ret; /* return any errors */
782 }
783
784 static void hvsi_close_protocol(struct hvsi_struct *hp)
785 {
786         struct hvsi_control packet __ALIGNED__;
787
788         packet.type = VS_CONTROL_PACKET_HEADER;
789         packet.seqno = atomic_inc_return(&hp->seqno);
790         packet.len = 6;
791         packet.verb = VSV_CLOSE_PROTOCOL;
792
793         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
794         dbg_dump_hex((uint8_t*)&packet, packet.len);
795
796         hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
797 }
798
799 static int hvsi_open(struct tty_struct *tty, struct file *filp)
800 {
801         struct hvsi_struct *hp;
802         unsigned long flags;
803         int line = tty->index;
804         int ret;
805
806         pr_debug("%s\n", __FUNCTION__);
807
808         if (line < 0 || line >= hvsi_count)
809                 return -ENODEV;
810         hp = &hvsi_ports[line];
811
812         tty->driver_data = hp;
813         tty->low_latency = 1; /* avoid throttle/tty_flip_buffer_push race */
814
815         mb();
816         if (hp->state == HVSI_FSP_DIED)
817                 return -EIO;
818
819         spin_lock_irqsave(&hp->lock, flags);
820         hp->tty = tty;
821         hp->count++;
822         atomic_set(&hp->seqno, 0);
823         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
824         spin_unlock_irqrestore(&hp->lock, flags);
825
826         if (is_console(hp))
827                 return 0; /* this has already been handshaked as the console */
828
829         ret = hvsi_handshake(hp);
830         if (ret < 0) {
831                 printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
832                 return ret;
833         }
834
835         ret = hvsi_get_mctrl(hp);
836         if (ret < 0) {
837                 printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name);
838                 return ret;
839         }
840
841         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
842         if (ret < 0) {
843                 printk(KERN_ERR "%s: couldn't set DTR\n", tty->name);
844                 return ret;
845         }
846
847         return 0;
848 }
849
850 /* wait for hvsi_write_worker to empty hp->outbuf */
851 static void hvsi_flush_output(struct hvsi_struct *hp)
852 {
853         wait_event_timeout(hp->emptyq, (hp->n_outbuf <= 0), HVSI_TIMEOUT);
854
855         /* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */
856         cancel_delayed_work(&hp->writer);
857         flush_scheduled_work();
858
859         /*
860          * it's also possible that our timeout expired and hvsi_write_worker
861          * didn't manage to push outbuf. poof.
862          */
863         hp->n_outbuf = 0;
864 }
865
866 static void hvsi_close(struct tty_struct *tty, struct file *filp)
867 {
868         struct hvsi_struct *hp = tty->driver_data;
869         unsigned long flags;
870
871         pr_debug("%s\n", __FUNCTION__);
872
873         if (tty_hung_up_p(filp))
874                 return;
875
876         spin_lock_irqsave(&hp->lock, flags);
877
878         if (--hp->count == 0) {
879                 hp->tty = NULL;
880                 hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
881
882                 /* only close down connection if it is not the console */
883                 if (!is_console(hp)) {
884                         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */
885                         __set_state(hp, HVSI_CLOSED);
886                         /*
887                          * any data delivered to the tty layer after this will be
888                          * discarded (except for XON/XOFF)
889                          */
890                         tty->closing = 1;
891
892                         spin_unlock_irqrestore(&hp->lock, flags);
893
894                         /* let any existing irq handlers finish. no more will start. */
895                         synchronize_irq(hp->virq);
896
897                         /* hvsi_write_worker will re-schedule until outbuf is empty. */
898                         hvsi_flush_output(hp);
899
900                         /* tell FSP to stop sending data */
901                         hvsi_close_protocol(hp);
902
903                         /*
904                          * drain anything FSP is still in the middle of sending, and let
905                          * hvsi_handshake drain the rest on the next open.
906                          */
907                         hvsi_drain_input(hp);
908
909                         spin_lock_irqsave(&hp->lock, flags);
910                 }
911         } else if (hp->count < 0)
912                 printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n",
913                        hp - hvsi_ports, hp->count);
914
915         spin_unlock_irqrestore(&hp->lock, flags);
916 }
917
918 static void hvsi_hangup(struct tty_struct *tty)
919 {
920         struct hvsi_struct *hp = tty->driver_data;
921         unsigned long flags;
922
923         pr_debug("%s\n", __FUNCTION__);
924
925         spin_lock_irqsave(&hp->lock, flags);
926
927         hp->count = 0;
928         hp->n_outbuf = 0;
929         hp->tty = NULL;
930
931         spin_unlock_irqrestore(&hp->lock, flags);
932 }
933
934 /* called with hp->lock held */
935 static void hvsi_push(struct hvsi_struct *hp)
936 {
937         int n;
938
939         if (hp->n_outbuf <= 0)
940                 return;
941
942         n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf);
943         if (n > 0) {
944                 /* success */
945                 pr_debug("%s: wrote %i chars\n", __FUNCTION__, n);
946                 hp->n_outbuf = 0;
947         } else if (n == -EIO) {
948                 __set_state(hp, HVSI_FSP_DIED);
949                 printk(KERN_ERR "hvsi%i: service processor died\n", hp->index);
950         }
951 }
952
953 /* hvsi_write_worker will keep rescheduling itself until outbuf is empty */
954 static void hvsi_write_worker(struct work_struct *work)
955 {
956         struct hvsi_struct *hp =
957                 container_of(work, struct hvsi_struct, writer.work);
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                 tty_wakeup(hp->tty);
992         }
993
994 out:
995         spin_unlock_irqrestore(&hp->lock, flags);
996 }
997
998 static int hvsi_write_room(struct tty_struct *tty)
999 {
1000         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1001
1002         return N_OUTBUF - hp->n_outbuf;
1003 }
1004
1005 static int hvsi_chars_in_buffer(struct tty_struct *tty)
1006 {
1007         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1008
1009         return hp->n_outbuf;
1010 }
1011
1012 static int hvsi_write(struct tty_struct *tty,
1013                      const unsigned char *buf, int count)
1014 {
1015         struct hvsi_struct *hp = tty->driver_data;
1016         const char *source = buf;
1017         unsigned long flags;
1018         int total = 0;
1019         int origcount = count;
1020
1021         spin_lock_irqsave(&hp->lock, flags);
1022
1023         pr_debug("%s: %i chars in buffer\n", __FUNCTION__, hp->n_outbuf);
1024
1025         if (!is_open(hp)) {
1026                 /* we're either closing or not yet open; don't accept data */
1027                 pr_debug("%s: not open\n", __FUNCTION__);
1028                 goto out;
1029         }
1030
1031         /*
1032          * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf
1033          * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls
1034          * will see there is no room in outbuf and return.
1035          */
1036         while ((count > 0) && (hvsi_write_room(hp->tty) > 0)) {
1037                 int chunksize = min(count, hvsi_write_room(hp->tty));
1038
1039                 BUG_ON(hp->n_outbuf < 0);
1040                 memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
1041                 hp->n_outbuf += chunksize;
1042
1043                 total += chunksize;
1044                 source += chunksize;
1045                 count -= chunksize;
1046                 hvsi_push(hp);
1047         }
1048
1049         if (hp->n_outbuf > 0) {
1050                 /*
1051                  * we weren't able to write it all to the hypervisor.
1052                  * schedule another push attempt.
1053                  */
1054                 schedule_delayed_work(&hp->writer, 10);
1055         }
1056
1057 out:
1058         spin_unlock_irqrestore(&hp->lock, flags);
1059
1060         if (total != origcount)
1061                 pr_debug("%s: wanted %i, only wrote %i\n", __FUNCTION__, origcount,
1062                         total);
1063
1064         return total;
1065 }
1066
1067 /*
1068  * I have never seen throttle or unthrottle called, so this little throttle
1069  * buffering scheme may or may not work.
1070  */
1071 static void hvsi_throttle(struct tty_struct *tty)
1072 {
1073         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1074
1075         pr_debug("%s\n", __FUNCTION__);
1076
1077         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE);
1078 }
1079
1080 static void hvsi_unthrottle(struct tty_struct *tty)
1081 {
1082         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1083         unsigned long flags;
1084         int shouldflip = 0;
1085
1086         pr_debug("%s\n", __FUNCTION__);
1087
1088         spin_lock_irqsave(&hp->lock, flags);
1089         if (hp->n_throttle) {
1090                 hvsi_send_overflow(hp);
1091                 shouldflip = 1;
1092         }
1093         spin_unlock_irqrestore(&hp->lock, flags);
1094
1095         if (shouldflip)
1096                 tty_flip_buffer_push(hp->tty);
1097
1098         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
1099 }
1100
1101 static int hvsi_tiocmget(struct tty_struct *tty, struct file *file)
1102 {
1103         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1104
1105         hvsi_get_mctrl(hp);
1106         return hp->mctrl;
1107 }
1108
1109 static int hvsi_tiocmset(struct tty_struct *tty, struct file *file,
1110                 unsigned int set, unsigned int clear)
1111 {
1112         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1113         unsigned long flags;
1114         uint16_t new_mctrl;
1115
1116         /* we can only alter DTR */
1117         clear &= TIOCM_DTR;
1118         set &= TIOCM_DTR;
1119
1120         spin_lock_irqsave(&hp->lock, flags);
1121
1122         new_mctrl = (hp->mctrl & ~clear) | set;
1123
1124         if (hp->mctrl != new_mctrl) {
1125                 hvsi_set_mctrl(hp, new_mctrl);
1126                 hp->mctrl = new_mctrl;
1127         }
1128         spin_unlock_irqrestore(&hp->lock, flags);
1129
1130         return 0;
1131 }
1132
1133
1134 static const struct tty_operations hvsi_ops = {
1135         .open = hvsi_open,
1136         .close = hvsi_close,
1137         .write = hvsi_write,
1138         .hangup = hvsi_hangup,
1139         .write_room = hvsi_write_room,
1140         .chars_in_buffer = hvsi_chars_in_buffer,
1141         .throttle = hvsi_throttle,
1142         .unthrottle = hvsi_unthrottle,
1143         .tiocmget = hvsi_tiocmget,
1144         .tiocmset = hvsi_tiocmset,
1145 };
1146
1147 static int __init hvsi_init(void)
1148 {
1149         int i;
1150
1151         hvsi_driver = alloc_tty_driver(hvsi_count);
1152         if (!hvsi_driver)
1153                 return -ENOMEM;
1154
1155         hvsi_driver->owner = THIS_MODULE;
1156         hvsi_driver->driver_name = "hvsi";
1157         hvsi_driver->name = "hvsi";
1158         hvsi_driver->major = HVSI_MAJOR;
1159         hvsi_driver->minor_start = HVSI_MINOR;
1160         hvsi_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1161         hvsi_driver->init_termios = tty_std_termios;
1162         hvsi_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
1163         hvsi_driver->init_termios.c_ispeed = 9600;
1164         hvsi_driver->init_termios.c_ospeed = 9600;
1165         hvsi_driver->flags = TTY_DRIVER_REAL_RAW;
1166         tty_set_operations(hvsi_driver, &hvsi_ops);
1167
1168         for (i=0; i < hvsi_count; i++) {
1169                 struct hvsi_struct *hp = &hvsi_ports[i];
1170                 int ret = 1;
1171
1172                 ret = request_irq(hp->virq, hvsi_interrupt, IRQF_DISABLED, "hvsi", hp);
1173                 if (ret)
1174                         printk(KERN_ERR "HVSI: couldn't reserve irq 0x%x (error %i)\n",
1175                                 hp->virq, ret);
1176         }
1177         hvsi_wait = wait_for_state; /* irqs active now */
1178
1179         if (tty_register_driver(hvsi_driver))
1180                 panic("Couldn't register hvsi console driver\n");
1181
1182         printk(KERN_DEBUG "HVSI: registered %i devices\n", hvsi_count);
1183
1184         return 0;
1185 }
1186 device_initcall(hvsi_init);
1187
1188 /***** console (not tty) code: *****/
1189
1190 static void hvsi_console_print(struct console *console, const char *buf,
1191                 unsigned int count)
1192 {
1193         struct hvsi_struct *hp = &hvsi_ports[console->index];
1194         char c[HVSI_MAX_OUTGOING_DATA] __ALIGNED__;
1195         unsigned int i = 0, n = 0;
1196         int ret, donecr = 0;
1197
1198         mb();
1199         if (!is_open(hp))
1200                 return;
1201
1202         /*
1203          * ugh, we have to translate LF -> CRLF ourselves, in place.
1204          * copied from hvc_console.c:
1205          */
1206         while (count > 0 || i > 0) {
1207                 if (count > 0 && i < sizeof(c)) {
1208                         if (buf[n] == '\n' && !donecr) {
1209                                 c[i++] = '\r';
1210                                 donecr = 1;
1211                         } else {
1212                                 c[i++] = buf[n++];
1213                                 donecr = 0;
1214                                 --count;
1215                         }
1216                 } else {
1217                         ret = hvsi_put_chars(hp, c, i);
1218                         if (ret < 0)
1219                                 i = 0;
1220                         i -= ret;
1221                 }
1222         }
1223 }
1224
1225 static struct tty_driver *hvsi_console_device(struct console *console,
1226         int *index)
1227 {
1228         *index = console->index;
1229         return hvsi_driver;
1230 }
1231
1232 static int __init hvsi_console_setup(struct console *console, char *options)
1233 {
1234         struct hvsi_struct *hp = &hvsi_ports[console->index];
1235         int ret;
1236
1237         if (console->index < 0 || console->index >= hvsi_count)
1238                 return -1;
1239
1240         /* give the FSP a chance to change the baud rate when we re-open */
1241         hvsi_close_protocol(hp);
1242
1243         ret = hvsi_handshake(hp);
1244         if (ret < 0)
1245                 return ret;
1246
1247         ret = hvsi_get_mctrl(hp);
1248         if (ret < 0)
1249                 return ret;
1250
1251         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
1252         if (ret < 0)
1253                 return ret;
1254
1255         hp->flags |= HVSI_CONSOLE;
1256
1257         return 0;
1258 }
1259
1260 static struct console hvsi_con_driver = {
1261         .name           = "hvsi",
1262         .write          = hvsi_console_print,
1263         .device         = hvsi_console_device,
1264         .setup          = hvsi_console_setup,
1265         .flags          = CON_PRINTBUFFER,
1266         .index          = -1,
1267 };
1268
1269 static int __init hvsi_console_init(void)
1270 {
1271         struct device_node *vty;
1272
1273         hvsi_wait = poll_for_state; /* no irqs yet; must poll */
1274
1275         /* search device tree for vty nodes */
1276         for (vty = of_find_compatible_node(NULL, "serial", "hvterm-protocol");
1277                         vty != NULL;
1278                         vty = of_find_compatible_node(vty, "serial", "hvterm-protocol")) {
1279                 struct hvsi_struct *hp;
1280                 const uint32_t *vtermno, *irq;
1281
1282                 vtermno = of_get_property(vty, "reg", NULL);
1283                 irq = of_get_property(vty, "interrupts", NULL);
1284                 if (!vtermno || !irq)
1285                         continue;
1286
1287                 if (hvsi_count >= MAX_NR_HVSI_CONSOLES) {
1288                         of_node_put(vty);
1289                         break;
1290                 }
1291
1292                 hp = &hvsi_ports[hvsi_count];
1293                 INIT_DELAYED_WORK(&hp->writer, hvsi_write_worker);
1294                 INIT_WORK(&hp->handshaker, hvsi_handshaker);
1295                 init_waitqueue_head(&hp->emptyq);
1296                 init_waitqueue_head(&hp->stateq);
1297                 spin_lock_init(&hp->lock);
1298                 hp->index = hvsi_count;
1299                 hp->inbuf_end = hp->inbuf;
1300                 hp->state = HVSI_CLOSED;
1301                 hp->vtermno = *vtermno;
1302                 hp->virq = irq_create_mapping(NULL, irq[0]);
1303                 if (hp->virq == NO_IRQ) {
1304                         printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
1305                                 __FUNCTION__, irq[0]);
1306                         continue;
1307                 }
1308
1309                 hvsi_count++;
1310         }
1311
1312         if (hvsi_count)
1313                 register_console(&hvsi_con_driver);
1314         return 0;
1315 }
1316 console_initcall(hvsi_console_init);