TTY: call tty_port_destroy in the rest of drivers
[linux-3.10.git] / drivers / tty / hvc / hvsi.c
1 /*
2  * Copyright (C) 2004 Hollis Blanchard <hollisb@us.ibm.com>, IBM
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
17  */
18
19 /* Host Virtual Serial Interface (HVSI) is a protocol between the hosted OS
20  * and the service processor on IBM pSeries servers. On these servers, there
21  * are no serial ports under the OS's control, and sometimes there is no other
22  * console available either. However, the service processor has two standard
23  * serial ports, so this over-complicated protocol allows the OS to control
24  * those ports by proxy.
25  *
26  * Besides data, the procotol supports the reading/writing of the serial
27  * port's DTR line, and the reading of the CD line. This is to allow the OS to
28  * control a modem attached to the service processor's serial port. Note that
29  * the OS cannot change the speed of the port through this protocol.
30  */
31
32 #undef DEBUG
33
34 #include <linux/console.h>
35 #include <linux/ctype.h>
36 #include <linux/delay.h>
37 #include <linux/init.h>
38 #include <linux/interrupt.h>
39 #include <linux/module.h>
40 #include <linux/major.h>
41 #include <linux/kernel.h>
42 #include <linux/spinlock.h>
43 #include <linux/sysrq.h>
44 #include <linux/tty.h>
45 #include <linux/tty_flip.h>
46 #include <asm/hvcall.h>
47 #include <asm/hvconsole.h>
48 #include <asm/prom.h>
49 #include <asm/uaccess.h>
50 #include <asm/vio.h>
51 #include <asm/param.h>
52 #include <asm/hvsi.h>
53
54 #define HVSI_MAJOR      229
55 #define HVSI_MINOR      128
56 #define MAX_NR_HVSI_CONSOLES 4
57
58 #define HVSI_TIMEOUT (5*HZ)
59 #define HVSI_VERSION 1
60 #define HVSI_MAX_PACKET 256
61 #define HVSI_MAX_READ 16
62 #define HVSI_MAX_OUTGOING_DATA 12
63 #define N_OUTBUF 12
64
65 /*
66  * we pass data via two 8-byte registers, so we would like our char arrays
67  * properly aligned for those loads.
68  */
69 #define __ALIGNED__     __attribute__((__aligned__(sizeof(long))))
70
71 struct hvsi_struct {
72         struct tty_port port;
73         struct delayed_work writer;
74         struct work_struct handshaker;
75         wait_queue_head_t emptyq; /* woken when outbuf is emptied */
76         wait_queue_head_t stateq; /* woken when HVSI state changes */
77         spinlock_t lock;
78         int index;
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 static inline int is_console(struct hvsi_struct *hp)
113 {
114         return hp->flags & HVSI_CONSOLE;
115 }
116
117 static inline int is_open(struct hvsi_struct *hp)
118 {
119         /* if we're waiting for an mctrl then we're already open */
120         return (hp->state == HVSI_OPEN)
121                         || (hp->state == HVSI_WAIT_FOR_MCTRL_RESPONSE);
122 }
123
124 static inline void print_state(struct hvsi_struct *hp)
125 {
126 #ifdef DEBUG
127         static const char *state_names[] = {
128                 "HVSI_CLOSED",
129                 "HVSI_WAIT_FOR_VER_RESPONSE",
130                 "HVSI_WAIT_FOR_VER_QUERY",
131                 "HVSI_OPEN",
132                 "HVSI_WAIT_FOR_MCTRL_RESPONSE",
133                 "HVSI_FSP_DIED",
134         };
135         const char *name = (hp->state < ARRAY_SIZE(state_names))
136                 ? state_names[hp->state] : "UNKNOWN";
137
138         pr_debug("hvsi%i: state = %s\n", hp->index, name);
139 #endif /* DEBUG */
140 }
141
142 static inline void __set_state(struct hvsi_struct *hp, int state)
143 {
144         hp->state = state;
145         print_state(hp);
146         wake_up_all(&hp->stateq);
147 }
148
149 static inline void set_state(struct hvsi_struct *hp, int state)
150 {
151         unsigned long flags;
152
153         spin_lock_irqsave(&hp->lock, flags);
154         __set_state(hp, state);
155         spin_unlock_irqrestore(&hp->lock, flags);
156 }
157
158 static inline int len_packet(const uint8_t *packet)
159 {
160         return (int)((struct hvsi_header *)packet)->len;
161 }
162
163 static inline int is_header(const uint8_t *packet)
164 {
165         struct hvsi_header *header = (struct hvsi_header *)packet;
166         return header->type >= VS_QUERY_RESPONSE_PACKET_HEADER;
167 }
168
169 static inline int got_packet(const struct hvsi_struct *hp, uint8_t *packet)
170 {
171         if (hp->inbuf_end < packet + sizeof(struct hvsi_header))
172                 return 0; /* don't even have the packet header */
173
174         if (hp->inbuf_end < (packet + len_packet(packet)))
175                 return 0; /* don't have the rest of the packet */
176
177         return 1;
178 }
179
180 /* shift remaining bytes in packetbuf down */
181 static void compact_inbuf(struct hvsi_struct *hp, uint8_t *read_to)
182 {
183         int remaining = (int)(hp->inbuf_end - read_to);
184
185         pr_debug("%s: %i chars remain\n", __func__, remaining);
186
187         if (read_to != hp->inbuf)
188                 memmove(hp->inbuf, read_to, remaining);
189
190         hp->inbuf_end = hp->inbuf + remaining;
191 }
192
193 #ifdef DEBUG
194 #define dbg_dump_packet(packet) dump_packet(packet)
195 #define dbg_dump_hex(data, len) dump_hex(data, len)
196 #else
197 #define dbg_dump_packet(packet) do { } while (0)
198 #define dbg_dump_hex(data, len) do { } while (0)
199 #endif
200
201 static void dump_hex(const uint8_t *data, int len)
202 {
203         int i;
204
205         printk("    ");
206         for (i=0; i < len; i++)
207                 printk("%.2x", data[i]);
208
209         printk("\n    ");
210         for (i=0; i < len; i++) {
211                 if (isprint(data[i]))
212                         printk("%c", data[i]);
213                 else
214                         printk(".");
215         }
216         printk("\n");
217 }
218
219 static void dump_packet(uint8_t *packet)
220 {
221         struct hvsi_header *header = (struct hvsi_header *)packet;
222
223         printk("type 0x%x, len %i, seqno %i:\n", header->type, header->len,
224                         header->seqno);
225
226         dump_hex(packet, header->len);
227 }
228
229 static int hvsi_read(struct hvsi_struct *hp, char *buf, int count)
230 {
231         unsigned long got;
232
233         got = hvc_get_chars(hp->vtermno, buf, count);
234
235         return got;
236 }
237
238 static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet,
239         struct tty_struct *tty, struct hvsi_struct **to_handshake)
240 {
241         struct hvsi_control *header = (struct hvsi_control *)packet;
242
243         switch (header->verb) {
244                 case VSV_MODEM_CTL_UPDATE:
245                         if ((header->word & HVSI_TSCD) == 0) {
246                                 /* CD went away; no more connection */
247                                 pr_debug("hvsi%i: CD dropped\n", hp->index);
248                                 hp->mctrl &= TIOCM_CD;
249                                 if (tty && !C_CLOCAL(tty))
250                                         tty_hangup(tty);
251                         }
252                         break;
253                 case VSV_CLOSE_PROTOCOL:
254                         pr_debug("hvsi%i: service processor came back\n", hp->index);
255                         if (hp->state != HVSI_CLOSED) {
256                                 *to_handshake = hp;
257                         }
258                         break;
259                 default:
260                         printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ",
261                                 hp->index);
262                         dump_packet(packet);
263                         break;
264         }
265 }
266
267 static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet)
268 {
269         struct hvsi_query_response *resp = (struct hvsi_query_response *)packet;
270
271         switch (hp->state) {
272                 case HVSI_WAIT_FOR_VER_RESPONSE:
273                         __set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
274                         break;
275                 case HVSI_WAIT_FOR_MCTRL_RESPONSE:
276                         hp->mctrl = 0;
277                         if (resp->u.mctrl_word & HVSI_TSDTR)
278                                 hp->mctrl |= TIOCM_DTR;
279                         if (resp->u.mctrl_word & HVSI_TSCD)
280                                 hp->mctrl |= TIOCM_CD;
281                         __set_state(hp, HVSI_OPEN);
282                         break;
283                 default:
284                         printk(KERN_ERR "hvsi%i: unexpected query response: ", hp->index);
285                         dump_packet(packet);
286                         break;
287         }
288 }
289
290 /* respond to service processor's version query */
291 static int hvsi_version_respond(struct hvsi_struct *hp, uint16_t query_seqno)
292 {
293         struct hvsi_query_response packet __ALIGNED__;
294         int wrote;
295
296         packet.hdr.type = VS_QUERY_RESPONSE_PACKET_HEADER;
297         packet.hdr.len = sizeof(struct hvsi_query_response);
298         packet.hdr.seqno = atomic_inc_return(&hp->seqno);
299         packet.verb = VSV_SEND_VERSION_NUMBER;
300         packet.u.version = HVSI_VERSION;
301         packet.query_seqno = query_seqno+1;
302
303         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
304         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
305
306         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
307         if (wrote != packet.hdr.len) {
308                 printk(KERN_ERR "hvsi%i: couldn't send query response!\n",
309                         hp->index);
310                 return -EIO;
311         }
312
313         return 0;
314 }
315
316 static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet)
317 {
318         struct hvsi_query *query = (struct hvsi_query *)packet;
319
320         switch (hp->state) {
321                 case HVSI_WAIT_FOR_VER_QUERY:
322                         hvsi_version_respond(hp, query->hdr.seqno);
323                         __set_state(hp, HVSI_OPEN);
324                         break;
325                 default:
326                         printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index);
327                         dump_packet(packet);
328                         break;
329         }
330 }
331
332 static void hvsi_insert_chars(struct hvsi_struct *hp, struct tty_struct *tty,
333                 const char *buf, int len)
334 {
335         int i;
336
337         for (i=0; i < len; i++) {
338                 char c = buf[i];
339 #ifdef CONFIG_MAGIC_SYSRQ
340                 if (c == '\0') {
341                         hp->sysrq = 1;
342                         continue;
343                 } else if (hp->sysrq) {
344                         handle_sysrq(c);
345                         hp->sysrq = 0;
346                         continue;
347                 }
348 #endif /* CONFIG_MAGIC_SYSRQ */
349                 tty_insert_flip_char(tty, c, 0);
350         }
351 }
352
353 /*
354  * We could get 252 bytes of data at once here. But the tty layer only
355  * throttles us at TTY_THRESHOLD_THROTTLE (128) bytes, so we could overflow
356  * it. Accordingly we won't send more than 128 bytes at a time to the flip
357  * buffer, which will give the tty buffer a chance to throttle us. Should the
358  * value of TTY_THRESHOLD_THROTTLE change in n_tty.c, this code should be
359  * revisited.
360  */
361 #define TTY_THRESHOLD_THROTTLE 128
362 static bool hvsi_recv_data(struct hvsi_struct *hp, struct tty_struct *tty,
363                 const uint8_t *packet)
364 {
365         const struct hvsi_header *header = (const struct hvsi_header *)packet;
366         const uint8_t *data = packet + sizeof(struct hvsi_header);
367         int datalen = header->len - sizeof(struct hvsi_header);
368         int overflow = datalen - TTY_THRESHOLD_THROTTLE;
369
370         pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data);
371
372         if (datalen == 0)
373                 return false;
374
375         if (overflow > 0) {
376                 pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __func__);
377                 datalen = TTY_THRESHOLD_THROTTLE;
378         }
379
380         hvsi_insert_chars(hp, tty, data, datalen);
381
382         if (overflow > 0) {
383                 /*
384                  * we still have more data to deliver, so we need to save off the
385                  * overflow and send it later
386                  */
387                 pr_debug("%s: deferring overflow\n", __func__);
388                 memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow);
389                 hp->n_throttle = overflow;
390         }
391
392         return true;
393 }
394
395 /*
396  * Returns true/false indicating data successfully read from hypervisor.
397  * Used both to get packets for tty connections and to advance the state
398  * machine during console handshaking (in which case tty = NULL and we ignore
399  * incoming data).
400  */
401 static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct *tty,
402                 struct hvsi_struct **handshake)
403 {
404         uint8_t *packet = hp->inbuf;
405         int chunklen;
406         bool flip = false;
407
408         *handshake = NULL;
409
410         chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
411         if (chunklen == 0) {
412                 pr_debug("%s: 0-length read\n", __func__);
413                 return 0;
414         }
415
416         pr_debug("%s: got %i bytes\n", __func__, chunklen);
417         dbg_dump_hex(hp->inbuf_end, chunklen);
418
419         hp->inbuf_end += chunklen;
420
421         /* handle all completed packets */
422         while ((packet < hp->inbuf_end) && got_packet(hp, packet)) {
423                 struct hvsi_header *header = (struct hvsi_header *)packet;
424
425                 if (!is_header(packet)) {
426                         printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index);
427                         /* skip bytes until we find a header or run out of data */
428                         while ((packet < hp->inbuf_end) && (!is_header(packet)))
429                                 packet++;
430                         continue;
431                 }
432
433                 pr_debug("%s: handling %i-byte packet\n", __func__,
434                                 len_packet(packet));
435                 dbg_dump_packet(packet);
436
437                 switch (header->type) {
438                         case VS_DATA_PACKET_HEADER:
439                                 if (!is_open(hp))
440                                         break;
441                                 if (tty == NULL)
442                                         break; /* no tty buffer to put data in */
443                                 flip = hvsi_recv_data(hp, tty, packet);
444                                 break;
445                         case VS_CONTROL_PACKET_HEADER:
446                                 hvsi_recv_control(hp, packet, tty, handshake);
447                                 break;
448                         case VS_QUERY_RESPONSE_PACKET_HEADER:
449                                 hvsi_recv_response(hp, packet);
450                                 break;
451                         case VS_QUERY_PACKET_HEADER:
452                                 hvsi_recv_query(hp, packet);
453                                 break;
454                         default:
455                                 printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
456                                                 hp->index, header->type);
457                                 dump_packet(packet);
458                                 break;
459                 }
460
461                 packet += len_packet(packet);
462
463                 if (*handshake) {
464                         pr_debug("%s: handshake\n", __func__);
465                         break;
466                 }
467         }
468
469         compact_inbuf(hp, packet);
470
471         if (flip)
472                 tty_flip_buffer_push(tty);
473
474         return 1;
475 }
476
477 static void hvsi_send_overflow(struct hvsi_struct *hp, struct tty_struct *tty)
478 {
479         pr_debug("%s: delivering %i bytes overflow\n", __func__,
480                         hp->n_throttle);
481
482         hvsi_insert_chars(hp, tty, hp->throttle_buf, hp->n_throttle);
483         hp->n_throttle = 0;
484 }
485
486 /*
487  * must get all pending data because we only get an irq on empty->non-empty
488  * transition
489  */
490 static irqreturn_t hvsi_interrupt(int irq, void *arg)
491 {
492         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
493         struct hvsi_struct *handshake;
494         struct tty_struct *tty;
495         unsigned long flags;
496         int again = 1;
497
498         pr_debug("%s\n", __func__);
499
500         tty = tty_port_tty_get(&hp->port);
501
502         while (again) {
503                 spin_lock_irqsave(&hp->lock, flags);
504                 again = hvsi_load_chunk(hp, tty, &handshake);
505                 spin_unlock_irqrestore(&hp->lock, flags);
506
507                 if (handshake) {
508                         pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
509                         schedule_work(&handshake->handshaker);
510                 }
511         }
512
513         spin_lock_irqsave(&hp->lock, flags);
514         if (tty && hp->n_throttle && !test_bit(TTY_THROTTLED, &tty->flags)) {
515                 /* we weren't hung up and we weren't throttled, so we can
516                  * deliver the rest now */
517                 hvsi_send_overflow(hp, tty);
518                 tty_flip_buffer_push(tty);
519         }
520         spin_unlock_irqrestore(&hp->lock, flags);
521
522         tty_kref_put(tty);
523
524         return IRQ_HANDLED;
525 }
526
527 /* for boot console, before the irq handler is running */
528 static int __init poll_for_state(struct hvsi_struct *hp, int state)
529 {
530         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
531
532         for (;;) {
533                 hvsi_interrupt(hp->virq, (void *)hp); /* get pending data */
534
535                 if (hp->state == state)
536                         return 0;
537
538                 mdelay(5);
539                 if (time_after(jiffies, end_jiffies))
540                         return -EIO;
541         }
542 }
543
544 /* wait for irq handler to change our state */
545 static int wait_for_state(struct hvsi_struct *hp, int state)
546 {
547         int ret = 0;
548
549         if (!wait_event_timeout(hp->stateq, (hp->state == state), HVSI_TIMEOUT))
550                 ret = -EIO;
551
552         return ret;
553 }
554
555 static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
556 {
557         struct hvsi_query packet __ALIGNED__;
558         int wrote;
559
560         packet.hdr.type = VS_QUERY_PACKET_HEADER;
561         packet.hdr.len = sizeof(struct hvsi_query);
562         packet.hdr.seqno = atomic_inc_return(&hp->seqno);
563         packet.verb = verb;
564
565         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
566         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
567
568         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
569         if (wrote != packet.hdr.len) {
570                 printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
571                         wrote);
572                 return -EIO;
573         }
574
575         return 0;
576 }
577
578 static int hvsi_get_mctrl(struct hvsi_struct *hp)
579 {
580         int ret;
581
582         set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
583         hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
584
585         ret = hvsi_wait(hp, HVSI_OPEN);
586         if (ret < 0) {
587                 printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
588                 set_state(hp, HVSI_OPEN);
589                 return ret;
590         }
591
592         pr_debug("%s: mctrl 0x%x\n", __func__, hp->mctrl);
593
594         return 0;
595 }
596
597 /* note that we can only set DTR */
598 static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
599 {
600         struct hvsi_control packet __ALIGNED__;
601         int wrote;
602
603         packet.hdr.type = VS_CONTROL_PACKET_HEADER,
604         packet.hdr.seqno = atomic_inc_return(&hp->seqno);
605         packet.hdr.len = sizeof(struct hvsi_control);
606         packet.verb = VSV_SET_MODEM_CTL;
607         packet.mask = HVSI_TSDTR;
608
609         if (mctrl & TIOCM_DTR)
610                 packet.word = HVSI_TSDTR;
611
612         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
613         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
614
615         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
616         if (wrote != packet.hdr.len) {
617                 printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
618                 return -EIO;
619         }
620
621         return 0;
622 }
623
624 static void hvsi_drain_input(struct hvsi_struct *hp)
625 {
626         uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
627         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
628
629         while (time_before(end_jiffies, jiffies))
630                 if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
631                         break;
632 }
633
634 static int hvsi_handshake(struct hvsi_struct *hp)
635 {
636         int ret;
637
638         /*
639          * We could have a CLOSE or other data waiting for us before we even try
640          * to open; try to throw it all away so we don't get confused. (CLOSE
641          * is the first message sent up the pipe when the FSP comes online. We
642          * need to distinguish between "it came up a while ago and we're the first
643          * user" and "it was just reset before it saw our handshake packet".)
644          */
645         hvsi_drain_input(hp);
646
647         set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
648         ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
649         if (ret < 0) {
650                 printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
651                 return ret;
652         }
653
654         ret = hvsi_wait(hp, HVSI_OPEN);
655         if (ret < 0)
656                 return ret;
657
658         return 0;
659 }
660
661 static void hvsi_handshaker(struct work_struct *work)
662 {
663         struct hvsi_struct *hp =
664                 container_of(work, struct hvsi_struct, handshaker);
665
666         if (hvsi_handshake(hp) >= 0)
667                 return;
668
669         printk(KERN_ERR "hvsi%i: re-handshaking failed\n", hp->index);
670         if (is_console(hp)) {
671                 /*
672                  * ttys will re-attempt the handshake via hvsi_open, but
673                  * the console will not.
674                  */
675                 printk(KERN_ERR "hvsi%i: lost console!\n", hp->index);
676         }
677 }
678
679 static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
680 {
681         struct hvsi_data packet __ALIGNED__;
682         int ret;
683
684         BUG_ON(count > HVSI_MAX_OUTGOING_DATA);
685
686         packet.hdr.type = VS_DATA_PACKET_HEADER;
687         packet.hdr.seqno = atomic_inc_return(&hp->seqno);
688         packet.hdr.len = count + sizeof(struct hvsi_header);
689         memcpy(&packet.data, buf, count);
690
691         ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
692         if (ret == packet.hdr.len) {
693                 /* return the number of chars written, not the packet length */
694                 return count;
695         }
696         return ret; /* return any errors */
697 }
698
699 static void hvsi_close_protocol(struct hvsi_struct *hp)
700 {
701         struct hvsi_control packet __ALIGNED__;
702
703         packet.hdr.type = VS_CONTROL_PACKET_HEADER;
704         packet.hdr.seqno = atomic_inc_return(&hp->seqno);
705         packet.hdr.len = 6;
706         packet.verb = VSV_CLOSE_PROTOCOL;
707
708         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
709         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
710
711         hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
712 }
713
714 static int hvsi_open(struct tty_struct *tty, struct file *filp)
715 {
716         struct hvsi_struct *hp;
717         unsigned long flags;
718         int ret;
719
720         pr_debug("%s\n", __func__);
721
722         hp = &hvsi_ports[tty->index];
723
724         tty->driver_data = hp;
725
726         mb();
727         if (hp->state == HVSI_FSP_DIED)
728                 return -EIO;
729
730         tty_port_tty_set(&hp->port, tty);
731         spin_lock_irqsave(&hp->lock, flags);
732         hp->port.count++;
733         atomic_set(&hp->seqno, 0);
734         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
735         spin_unlock_irqrestore(&hp->lock, flags);
736
737         if (is_console(hp))
738                 return 0; /* this has already been handshaked as the console */
739
740         ret = hvsi_handshake(hp);
741         if (ret < 0) {
742                 printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
743                 return ret;
744         }
745
746         ret = hvsi_get_mctrl(hp);
747         if (ret < 0) {
748                 printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name);
749                 return ret;
750         }
751
752         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
753         if (ret < 0) {
754                 printk(KERN_ERR "%s: couldn't set DTR\n", tty->name);
755                 return ret;
756         }
757
758         return 0;
759 }
760
761 /* wait for hvsi_write_worker to empty hp->outbuf */
762 static void hvsi_flush_output(struct hvsi_struct *hp)
763 {
764         wait_event_timeout(hp->emptyq, (hp->n_outbuf <= 0), HVSI_TIMEOUT);
765
766         /* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */
767         cancel_delayed_work_sync(&hp->writer);
768         flush_work(&hp->handshaker);
769
770         /*
771          * it's also possible that our timeout expired and hvsi_write_worker
772          * didn't manage to push outbuf. poof.
773          */
774         hp->n_outbuf = 0;
775 }
776
777 static void hvsi_close(struct tty_struct *tty, struct file *filp)
778 {
779         struct hvsi_struct *hp = tty->driver_data;
780         unsigned long flags;
781
782         pr_debug("%s\n", __func__);
783
784         if (tty_hung_up_p(filp))
785                 return;
786
787         spin_lock_irqsave(&hp->lock, flags);
788
789         if (--hp->port.count == 0) {
790                 tty_port_tty_set(&hp->port, NULL);
791                 hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
792
793                 /* only close down connection if it is not the console */
794                 if (!is_console(hp)) {
795                         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */
796                         __set_state(hp, HVSI_CLOSED);
797                         /*
798                          * any data delivered to the tty layer after this will be
799                          * discarded (except for XON/XOFF)
800                          */
801                         tty->closing = 1;
802
803                         spin_unlock_irqrestore(&hp->lock, flags);
804
805                         /* let any existing irq handlers finish. no more will start. */
806                         synchronize_irq(hp->virq);
807
808                         /* hvsi_write_worker will re-schedule until outbuf is empty. */
809                         hvsi_flush_output(hp);
810
811                         /* tell FSP to stop sending data */
812                         hvsi_close_protocol(hp);
813
814                         /*
815                          * drain anything FSP is still in the middle of sending, and let
816                          * hvsi_handshake drain the rest on the next open.
817                          */
818                         hvsi_drain_input(hp);
819
820                         spin_lock_irqsave(&hp->lock, flags);
821                 }
822         } else if (hp->port.count < 0)
823                 printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n",
824                        hp - hvsi_ports, hp->port.count);
825
826         spin_unlock_irqrestore(&hp->lock, flags);
827 }
828
829 static void hvsi_hangup(struct tty_struct *tty)
830 {
831         struct hvsi_struct *hp = tty->driver_data;
832         unsigned long flags;
833
834         pr_debug("%s\n", __func__);
835
836         tty_port_tty_set(&hp->port, NULL);
837
838         spin_lock_irqsave(&hp->lock, flags);
839         hp->port.count = 0;
840         hp->n_outbuf = 0;
841         spin_unlock_irqrestore(&hp->lock, flags);
842 }
843
844 /* called with hp->lock held */
845 static void hvsi_push(struct hvsi_struct *hp)
846 {
847         int n;
848
849         if (hp->n_outbuf <= 0)
850                 return;
851
852         n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf);
853         if (n > 0) {
854                 /* success */
855                 pr_debug("%s: wrote %i chars\n", __func__, n);
856                 hp->n_outbuf = 0;
857         } else if (n == -EIO) {
858                 __set_state(hp, HVSI_FSP_DIED);
859                 printk(KERN_ERR "hvsi%i: service processor died\n", hp->index);
860         }
861 }
862
863 /* hvsi_write_worker will keep rescheduling itself until outbuf is empty */
864 static void hvsi_write_worker(struct work_struct *work)
865 {
866         struct hvsi_struct *hp =
867                 container_of(work, struct hvsi_struct, writer.work);
868         struct tty_struct *tty;
869         unsigned long flags;
870 #ifdef DEBUG
871         static long start_j = 0;
872
873         if (start_j == 0)
874                 start_j = jiffies;
875 #endif /* DEBUG */
876
877         spin_lock_irqsave(&hp->lock, flags);
878
879         pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
880
881         if (!is_open(hp)) {
882                 /*
883                  * We could have a non-open connection if the service processor died
884                  * while we were busily scheduling ourselves. In that case, it could
885                  * be minutes before the service processor comes back, so only try
886                  * again once a second.
887                  */
888                 schedule_delayed_work(&hp->writer, HZ);
889                 goto out;
890         }
891
892         hvsi_push(hp);
893         if (hp->n_outbuf > 0)
894                 schedule_delayed_work(&hp->writer, 10);
895         else {
896 #ifdef DEBUG
897                 pr_debug("%s: outbuf emptied after %li jiffies\n", __func__,
898                                 jiffies - start_j);
899                 start_j = 0;
900 #endif /* DEBUG */
901                 wake_up_all(&hp->emptyq);
902                 tty = tty_port_tty_get(&hp->port);
903                 if (tty) {
904                         tty_wakeup(tty);
905                         tty_kref_put(tty);
906                 }
907         }
908
909 out:
910         spin_unlock_irqrestore(&hp->lock, flags);
911 }
912
913 static int hvsi_write_room(struct tty_struct *tty)
914 {
915         struct hvsi_struct *hp = tty->driver_data;
916
917         return N_OUTBUF - hp->n_outbuf;
918 }
919
920 static int hvsi_chars_in_buffer(struct tty_struct *tty)
921 {
922         struct hvsi_struct *hp = tty->driver_data;
923
924         return hp->n_outbuf;
925 }
926
927 static int hvsi_write(struct tty_struct *tty,
928                      const unsigned char *buf, int count)
929 {
930         struct hvsi_struct *hp = tty->driver_data;
931         const char *source = buf;
932         unsigned long flags;
933         int total = 0;
934         int origcount = count;
935
936         spin_lock_irqsave(&hp->lock, flags);
937
938         pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
939
940         if (!is_open(hp)) {
941                 /* we're either closing or not yet open; don't accept data */
942                 pr_debug("%s: not open\n", __func__);
943                 goto out;
944         }
945
946         /*
947          * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf
948          * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls
949          * will see there is no room in outbuf and return.
950          */
951         while ((count > 0) && (hvsi_write_room(tty) > 0)) {
952                 int chunksize = min(count, hvsi_write_room(tty));
953
954                 BUG_ON(hp->n_outbuf < 0);
955                 memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
956                 hp->n_outbuf += chunksize;
957
958                 total += chunksize;
959                 source += chunksize;
960                 count -= chunksize;
961                 hvsi_push(hp);
962         }
963
964         if (hp->n_outbuf > 0) {
965                 /*
966                  * we weren't able to write it all to the hypervisor.
967                  * schedule another push attempt.
968                  */
969                 schedule_delayed_work(&hp->writer, 10);
970         }
971
972 out:
973         spin_unlock_irqrestore(&hp->lock, flags);
974
975         if (total != origcount)
976                 pr_debug("%s: wanted %i, only wrote %i\n", __func__, origcount,
977                         total);
978
979         return total;
980 }
981
982 /*
983  * I have never seen throttle or unthrottle called, so this little throttle
984  * buffering scheme may or may not work.
985  */
986 static void hvsi_throttle(struct tty_struct *tty)
987 {
988         struct hvsi_struct *hp = tty->driver_data;
989
990         pr_debug("%s\n", __func__);
991
992         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE);
993 }
994
995 static void hvsi_unthrottle(struct tty_struct *tty)
996 {
997         struct hvsi_struct *hp = tty->driver_data;
998         unsigned long flags;
999
1000         pr_debug("%s\n", __func__);
1001
1002         spin_lock_irqsave(&hp->lock, flags);
1003         if (hp->n_throttle) {
1004                 hvsi_send_overflow(hp, tty);
1005                 tty_flip_buffer_push(tty);
1006         }
1007         spin_unlock_irqrestore(&hp->lock, flags);
1008
1009
1010         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
1011 }
1012
1013 static int hvsi_tiocmget(struct tty_struct *tty)
1014 {
1015         struct hvsi_struct *hp = tty->driver_data;
1016
1017         hvsi_get_mctrl(hp);
1018         return hp->mctrl;
1019 }
1020
1021 static int hvsi_tiocmset(struct tty_struct *tty,
1022                                 unsigned int set, unsigned int clear)
1023 {
1024         struct hvsi_struct *hp = tty->driver_data;
1025         unsigned long flags;
1026         uint16_t new_mctrl;
1027
1028         /* we can only alter DTR */
1029         clear &= TIOCM_DTR;
1030         set &= TIOCM_DTR;
1031
1032         spin_lock_irqsave(&hp->lock, flags);
1033
1034         new_mctrl = (hp->mctrl & ~clear) | set;
1035
1036         if (hp->mctrl != new_mctrl) {
1037                 hvsi_set_mctrl(hp, new_mctrl);
1038                 hp->mctrl = new_mctrl;
1039         }
1040         spin_unlock_irqrestore(&hp->lock, flags);
1041
1042         return 0;
1043 }
1044
1045
1046 static const struct tty_operations hvsi_ops = {
1047         .open = hvsi_open,
1048         .close = hvsi_close,
1049         .write = hvsi_write,
1050         .hangup = hvsi_hangup,
1051         .write_room = hvsi_write_room,
1052         .chars_in_buffer = hvsi_chars_in_buffer,
1053         .throttle = hvsi_throttle,
1054         .unthrottle = hvsi_unthrottle,
1055         .tiocmget = hvsi_tiocmget,
1056         .tiocmset = hvsi_tiocmset,
1057 };
1058
1059 static int __init hvsi_init(void)
1060 {
1061         int i;
1062
1063         hvsi_driver = alloc_tty_driver(hvsi_count);
1064         if (!hvsi_driver)
1065                 return -ENOMEM;
1066
1067         hvsi_driver->driver_name = "hvsi";
1068         hvsi_driver->name = "hvsi";
1069         hvsi_driver->major = HVSI_MAJOR;
1070         hvsi_driver->minor_start = HVSI_MINOR;
1071         hvsi_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1072         hvsi_driver->init_termios = tty_std_termios;
1073         hvsi_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
1074         hvsi_driver->init_termios.c_ispeed = 9600;
1075         hvsi_driver->init_termios.c_ospeed = 9600;
1076         hvsi_driver->flags = TTY_DRIVER_REAL_RAW;
1077         tty_set_operations(hvsi_driver, &hvsi_ops);
1078
1079         for (i=0; i < hvsi_count; i++) {
1080                 struct hvsi_struct *hp = &hvsi_ports[i];
1081                 int ret = 1;
1082
1083                 tty_port_link_device(&hp->port, hvsi_driver, i);
1084
1085                 ret = request_irq(hp->virq, hvsi_interrupt, 0, "hvsi", hp);
1086                 if (ret)
1087                         printk(KERN_ERR "HVSI: couldn't reserve irq 0x%x (error %i)\n",
1088                                 hp->virq, ret);
1089         }
1090         hvsi_wait = wait_for_state; /* irqs active now */
1091
1092         if (tty_register_driver(hvsi_driver))
1093                 panic("Couldn't register hvsi console driver\n");
1094
1095         printk(KERN_DEBUG "HVSI: registered %i devices\n", hvsi_count);
1096
1097         return 0;
1098 }
1099 device_initcall(hvsi_init);
1100
1101 /***** console (not tty) code: *****/
1102
1103 static void hvsi_console_print(struct console *console, const char *buf,
1104                 unsigned int count)
1105 {
1106         struct hvsi_struct *hp = &hvsi_ports[console->index];
1107         char c[HVSI_MAX_OUTGOING_DATA] __ALIGNED__;
1108         unsigned int i = 0, n = 0;
1109         int ret, donecr = 0;
1110
1111         mb();
1112         if (!is_open(hp))
1113                 return;
1114
1115         /*
1116          * ugh, we have to translate LF -> CRLF ourselves, in place.
1117          * copied from hvc_console.c:
1118          */
1119         while (count > 0 || i > 0) {
1120                 if (count > 0 && i < sizeof(c)) {
1121                         if (buf[n] == '\n' && !donecr) {
1122                                 c[i++] = '\r';
1123                                 donecr = 1;
1124                         } else {
1125                                 c[i++] = buf[n++];
1126                                 donecr = 0;
1127                                 --count;
1128                         }
1129                 } else {
1130                         ret = hvsi_put_chars(hp, c, i);
1131                         if (ret < 0)
1132                                 i = 0;
1133                         i -= ret;
1134                 }
1135         }
1136 }
1137
1138 static struct tty_driver *hvsi_console_device(struct console *console,
1139         int *index)
1140 {
1141         *index = console->index;
1142         return hvsi_driver;
1143 }
1144
1145 static int __init hvsi_console_setup(struct console *console, char *options)
1146 {
1147         struct hvsi_struct *hp;
1148         int ret;
1149
1150         if (console->index < 0 || console->index >= hvsi_count)
1151                 return -1;
1152         hp = &hvsi_ports[console->index];
1153
1154         /* give the FSP a chance to change the baud rate when we re-open */
1155         hvsi_close_protocol(hp);
1156
1157         ret = hvsi_handshake(hp);
1158         if (ret < 0)
1159                 return ret;
1160
1161         ret = hvsi_get_mctrl(hp);
1162         if (ret < 0)
1163                 return ret;
1164
1165         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
1166         if (ret < 0)
1167                 return ret;
1168
1169         hp->flags |= HVSI_CONSOLE;
1170
1171         return 0;
1172 }
1173
1174 static struct console hvsi_console = {
1175         .name           = "hvsi",
1176         .write          = hvsi_console_print,
1177         .device         = hvsi_console_device,
1178         .setup          = hvsi_console_setup,
1179         .flags          = CON_PRINTBUFFER,
1180         .index          = -1,
1181 };
1182
1183 static int __init hvsi_console_init(void)
1184 {
1185         struct device_node *vty;
1186
1187         hvsi_wait = poll_for_state; /* no irqs yet; must poll */
1188
1189         /* search device tree for vty nodes */
1190         for (vty = of_find_compatible_node(NULL, "serial", "hvterm-protocol");
1191                         vty != NULL;
1192                         vty = of_find_compatible_node(vty, "serial", "hvterm-protocol")) {
1193                 struct hvsi_struct *hp;
1194                 const uint32_t *vtermno, *irq;
1195
1196                 vtermno = of_get_property(vty, "reg", NULL);
1197                 irq = of_get_property(vty, "interrupts", NULL);
1198                 if (!vtermno || !irq)
1199                         continue;
1200
1201                 if (hvsi_count >= MAX_NR_HVSI_CONSOLES) {
1202                         of_node_put(vty);
1203                         break;
1204                 }
1205
1206                 hp = &hvsi_ports[hvsi_count];
1207                 INIT_DELAYED_WORK(&hp->writer, hvsi_write_worker);
1208                 INIT_WORK(&hp->handshaker, hvsi_handshaker);
1209                 init_waitqueue_head(&hp->emptyq);
1210                 init_waitqueue_head(&hp->stateq);
1211                 spin_lock_init(&hp->lock);
1212                 tty_port_init(&hp->port);
1213                 hp->index = hvsi_count;
1214                 hp->inbuf_end = hp->inbuf;
1215                 hp->state = HVSI_CLOSED;
1216                 hp->vtermno = *vtermno;
1217                 hp->virq = irq_create_mapping(NULL, irq[0]);
1218                 if (hp->virq == 0) {
1219                         printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
1220                                 __func__, irq[0]);
1221                         tty_port_destroy(&hp->port);
1222                         continue;
1223                 }
1224
1225                 hvsi_count++;
1226         }
1227
1228         if (hvsi_count)
1229                 register_console(&hvsi_console);
1230         return 0;
1231 }
1232 console_initcall(hvsi_console_init);