GNU Linux-libre 4.9.337-gnu1
[releases.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 (be16_to_cpu(header->verb)) {
244                 case VSV_MODEM_CTL_UPDATE:
245                         if ((be32_to_cpu(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         uint32_t mctrl_word;
271
272         switch (hp->state) {
273                 case HVSI_WAIT_FOR_VER_RESPONSE:
274                         __set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
275                         break;
276                 case HVSI_WAIT_FOR_MCTRL_RESPONSE:
277                         hp->mctrl = 0;
278                         mctrl_word = be32_to_cpu(resp->u.mctrl_word);
279                         if (mctrl_word & HVSI_TSDTR)
280                                 hp->mctrl |= TIOCM_DTR;
281                         if (mctrl_word & HVSI_TSCD)
282                                 hp->mctrl |= TIOCM_CD;
283                         __set_state(hp, HVSI_OPEN);
284                         break;
285                 default:
286                         printk(KERN_ERR "hvsi%i: unexpected query response: ", hp->index);
287                         dump_packet(packet);
288                         break;
289         }
290 }
291
292 /* respond to service processor's version query */
293 static int hvsi_version_respond(struct hvsi_struct *hp, uint16_t query_seqno)
294 {
295         struct hvsi_query_response packet __ALIGNED__;
296         int wrote;
297
298         packet.hdr.type = VS_QUERY_RESPONSE_PACKET_HEADER;
299         packet.hdr.len = sizeof(struct hvsi_query_response);
300         packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno));
301         packet.verb = cpu_to_be16(VSV_SEND_VERSION_NUMBER);
302         packet.u.version = HVSI_VERSION;
303         packet.query_seqno = cpu_to_be16(query_seqno+1);
304
305         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
306         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
307
308         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
309         if (wrote != packet.hdr.len) {
310                 printk(KERN_ERR "hvsi%i: couldn't send query response!\n",
311                         hp->index);
312                 return -EIO;
313         }
314
315         return 0;
316 }
317
318 static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet)
319 {
320         struct hvsi_query *query = (struct hvsi_query *)packet;
321
322         switch (hp->state) {
323                 case HVSI_WAIT_FOR_VER_QUERY:
324                         hvsi_version_respond(hp, be16_to_cpu(query->hdr.seqno));
325                         __set_state(hp, HVSI_OPEN);
326                         break;
327                 default:
328                         printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index);
329                         dump_packet(packet);
330                         break;
331         }
332 }
333
334 static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len)
335 {
336         int i;
337
338         for (i=0; i < len; i++) {
339                 char c = buf[i];
340 #ifdef CONFIG_MAGIC_SYSRQ
341                 if (c == '\0') {
342                         hp->sysrq = 1;
343                         continue;
344                 } else if (hp->sysrq) {
345                         handle_sysrq(c);
346                         hp->sysrq = 0;
347                         continue;
348                 }
349 #endif /* CONFIG_MAGIC_SYSRQ */
350                 tty_insert_flip_char(&hp->port, c, 0);
351         }
352 }
353
354 /*
355  * We could get 252 bytes of data at once here. But the tty layer only
356  * throttles us at TTY_THRESHOLD_THROTTLE (128) bytes, so we could overflow
357  * it. Accordingly we won't send more than 128 bytes at a time to the flip
358  * buffer, which will give the tty buffer a chance to throttle us. Should the
359  * value of TTY_THRESHOLD_THROTTLE change in n_tty.c, this code should be
360  * revisited.
361  */
362 #define TTY_THRESHOLD_THROTTLE 128
363 static bool hvsi_recv_data(struct hvsi_struct *hp, 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, 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                                 flip = hvsi_recv_data(hp, packet);
442                                 break;
443                         case VS_CONTROL_PACKET_HEADER:
444                                 hvsi_recv_control(hp, packet, tty, handshake);
445                                 break;
446                         case VS_QUERY_RESPONSE_PACKET_HEADER:
447                                 hvsi_recv_response(hp, packet);
448                                 break;
449                         case VS_QUERY_PACKET_HEADER:
450                                 hvsi_recv_query(hp, packet);
451                                 break;
452                         default:
453                                 printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
454                                                 hp->index, header->type);
455                                 dump_packet(packet);
456                                 break;
457                 }
458
459                 packet += len_packet(packet);
460
461                 if (*handshake) {
462                         pr_debug("%s: handshake\n", __func__);
463                         break;
464                 }
465         }
466
467         compact_inbuf(hp, packet);
468
469         if (flip)
470                 tty_flip_buffer_push(&hp->port);
471
472         return 1;
473 }
474
475 static void hvsi_send_overflow(struct hvsi_struct *hp)
476 {
477         pr_debug("%s: delivering %i bytes overflow\n", __func__,
478                         hp->n_throttle);
479
480         hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);
481         hp->n_throttle = 0;
482 }
483
484 /*
485  * must get all pending data because we only get an irq on empty->non-empty
486  * transition
487  */
488 static irqreturn_t hvsi_interrupt(int irq, void *arg)
489 {
490         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
491         struct hvsi_struct *handshake;
492         struct tty_struct *tty;
493         unsigned long flags;
494         int again = 1;
495
496         pr_debug("%s\n", __func__);
497
498         tty = tty_port_tty_get(&hp->port);
499
500         while (again) {
501                 spin_lock_irqsave(&hp->lock, flags);
502                 again = hvsi_load_chunk(hp, tty, &handshake);
503                 spin_unlock_irqrestore(&hp->lock, flags);
504
505                 if (handshake) {
506                         pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
507                         schedule_work(&handshake->handshaker);
508                 }
509         }
510
511         spin_lock_irqsave(&hp->lock, flags);
512         if (tty && hp->n_throttle && !tty_throttled(tty)) {
513                 /* we weren't hung up and we weren't throttled, so we can
514                  * deliver the rest now */
515                 hvsi_send_overflow(hp);
516                 tty_flip_buffer_push(&hp->port);
517         }
518         spin_unlock_irqrestore(&hp->lock, flags);
519
520         tty_kref_put(tty);
521
522         return IRQ_HANDLED;
523 }
524
525 /* for boot console, before the irq handler is running */
526 static int __init poll_for_state(struct hvsi_struct *hp, int state)
527 {
528         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
529
530         for (;;) {
531                 hvsi_interrupt(hp->virq, (void *)hp); /* get pending data */
532
533                 if (hp->state == state)
534                         return 0;
535
536                 mdelay(5);
537                 if (time_after(jiffies, end_jiffies))
538                         return -EIO;
539         }
540 }
541
542 /* wait for irq handler to change our state */
543 static int wait_for_state(struct hvsi_struct *hp, int state)
544 {
545         int ret = 0;
546
547         if (!wait_event_timeout(hp->stateq, (hp->state == state), HVSI_TIMEOUT))
548                 ret = -EIO;
549
550         return ret;
551 }
552
553 static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
554 {
555         struct hvsi_query packet __ALIGNED__;
556         int wrote;
557
558         packet.hdr.type = VS_QUERY_PACKET_HEADER;
559         packet.hdr.len = sizeof(struct hvsi_query);
560         packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno));
561         packet.verb = cpu_to_be16(verb);
562
563         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
564         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
565
566         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
567         if (wrote != packet.hdr.len) {
568                 printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
569                         wrote);
570                 return -EIO;
571         }
572
573         return 0;
574 }
575
576 static int hvsi_get_mctrl(struct hvsi_struct *hp)
577 {
578         int ret;
579
580         set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
581         hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
582
583         ret = hvsi_wait(hp, HVSI_OPEN);
584         if (ret < 0) {
585                 printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
586                 set_state(hp, HVSI_OPEN);
587                 return ret;
588         }
589
590         pr_debug("%s: mctrl 0x%x\n", __func__, hp->mctrl);
591
592         return 0;
593 }
594
595 /* note that we can only set DTR */
596 static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
597 {
598         struct hvsi_control packet __ALIGNED__;
599         int wrote;
600
601         packet.hdr.type = VS_CONTROL_PACKET_HEADER;
602         packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno));
603         packet.hdr.len = sizeof(struct hvsi_control);
604         packet.verb = cpu_to_be16(VSV_SET_MODEM_CTL);
605         packet.mask = cpu_to_be32(HVSI_TSDTR);
606
607         if (mctrl & TIOCM_DTR)
608                 packet.word = cpu_to_be32(HVSI_TSDTR);
609
610         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
611         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
612
613         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
614         if (wrote != packet.hdr.len) {
615                 printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
616                 return -EIO;
617         }
618
619         return 0;
620 }
621
622 static void hvsi_drain_input(struct hvsi_struct *hp)
623 {
624         uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
625         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
626
627         while (time_before(end_jiffies, jiffies))
628                 if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
629                         break;
630 }
631
632 static int hvsi_handshake(struct hvsi_struct *hp)
633 {
634         int ret;
635
636         /*
637          * We could have a CLOSE or other data waiting for us before we even try
638          * to open; try to throw it all away so we don't get confused. (CLOSE
639          * is the first message sent up the pipe when the FSP comes online. We
640          * need to distinguish between "it came up a while ago and we're the first
641          * user" and "it was just reset before it saw our handshake packet".)
642          */
643         hvsi_drain_input(hp);
644
645         set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
646         ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
647         if (ret < 0) {
648                 printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
649                 return ret;
650         }
651
652         ret = hvsi_wait(hp, HVSI_OPEN);
653         if (ret < 0)
654                 return ret;
655
656         return 0;
657 }
658
659 static void hvsi_handshaker(struct work_struct *work)
660 {
661         struct hvsi_struct *hp =
662                 container_of(work, struct hvsi_struct, handshaker);
663
664         if (hvsi_handshake(hp) >= 0)
665                 return;
666
667         printk(KERN_ERR "hvsi%i: re-handshaking failed\n", hp->index);
668         if (is_console(hp)) {
669                 /*
670                  * ttys will re-attempt the handshake via hvsi_open, but
671                  * the console will not.
672                  */
673                 printk(KERN_ERR "hvsi%i: lost console!\n", hp->index);
674         }
675 }
676
677 static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
678 {
679         struct hvsi_data packet __ALIGNED__;
680         int ret;
681
682         BUG_ON(count > HVSI_MAX_OUTGOING_DATA);
683
684         packet.hdr.type = VS_DATA_PACKET_HEADER;
685         packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno));
686         packet.hdr.len = count + sizeof(struct hvsi_header);
687         memcpy(&packet.data, buf, count);
688
689         ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
690         if (ret == packet.hdr.len) {
691                 /* return the number of chars written, not the packet length */
692                 return count;
693         }
694         return ret; /* return any errors */
695 }
696
697 static void hvsi_close_protocol(struct hvsi_struct *hp)
698 {
699         struct hvsi_control packet __ALIGNED__;
700
701         packet.hdr.type = VS_CONTROL_PACKET_HEADER;
702         packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno));
703         packet.hdr.len = 6;
704         packet.verb = cpu_to_be16(VSV_CLOSE_PROTOCOL);
705
706         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
707         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
708
709         hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
710 }
711
712 static int hvsi_open(struct tty_struct *tty, struct file *filp)
713 {
714         struct hvsi_struct *hp;
715         unsigned long flags;
716         int ret;
717
718         pr_debug("%s\n", __func__);
719
720         hp = &hvsi_ports[tty->index];
721
722         tty->driver_data = hp;
723
724         mb();
725         if (hp->state == HVSI_FSP_DIED)
726                 return -EIO;
727
728         tty_port_tty_set(&hp->port, tty);
729         spin_lock_irqsave(&hp->lock, flags);
730         hp->port.count++;
731         atomic_set(&hp->seqno, 0);
732         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
733         spin_unlock_irqrestore(&hp->lock, flags);
734
735         if (is_console(hp))
736                 return 0; /* this has already been handshaked as the console */
737
738         ret = hvsi_handshake(hp);
739         if (ret < 0) {
740                 printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
741                 return ret;
742         }
743
744         ret = hvsi_get_mctrl(hp);
745         if (ret < 0) {
746                 printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name);
747                 return ret;
748         }
749
750         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
751         if (ret < 0) {
752                 printk(KERN_ERR "%s: couldn't set DTR\n", tty->name);
753                 return ret;
754         }
755
756         return 0;
757 }
758
759 /* wait for hvsi_write_worker to empty hp->outbuf */
760 static void hvsi_flush_output(struct hvsi_struct *hp)
761 {
762         wait_event_timeout(hp->emptyq, (hp->n_outbuf <= 0), HVSI_TIMEOUT);
763
764         /* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */
765         cancel_delayed_work_sync(&hp->writer);
766         flush_work(&hp->handshaker);
767
768         /*
769          * it's also possible that our timeout expired and hvsi_write_worker
770          * didn't manage to push outbuf. poof.
771          */
772         hp->n_outbuf = 0;
773 }
774
775 static void hvsi_close(struct tty_struct *tty, struct file *filp)
776 {
777         struct hvsi_struct *hp = tty->driver_data;
778         unsigned long flags;
779
780         pr_debug("%s\n", __func__);
781
782         if (tty_hung_up_p(filp))
783                 return;
784
785         spin_lock_irqsave(&hp->lock, flags);
786
787         if (--hp->port.count == 0) {
788                 tty_port_tty_set(&hp->port, NULL);
789                 hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
790
791                 /* only close down connection if it is not the console */
792                 if (!is_console(hp)) {
793                         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */
794                         __set_state(hp, HVSI_CLOSED);
795                         /*
796                          * any data delivered to the tty layer after this will be
797                          * discarded (except for XON/XOFF)
798                          */
799                         tty->closing = 1;
800
801                         spin_unlock_irqrestore(&hp->lock, flags);
802
803                         /* let any existing irq handlers finish. no more will start. */
804                         synchronize_irq(hp->virq);
805
806                         /* hvsi_write_worker will re-schedule until outbuf is empty. */
807                         hvsi_flush_output(hp);
808
809                         /* tell FSP to stop sending data */
810                         hvsi_close_protocol(hp);
811
812                         /*
813                          * drain anything FSP is still in the middle of sending, and let
814                          * hvsi_handshake drain the rest on the next open.
815                          */
816                         hvsi_drain_input(hp);
817
818                         spin_lock_irqsave(&hp->lock, flags);
819                 }
820         } else if (hp->port.count < 0)
821                 printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n",
822                        hp - hvsi_ports, hp->port.count);
823
824         spin_unlock_irqrestore(&hp->lock, flags);
825 }
826
827 static void hvsi_hangup(struct tty_struct *tty)
828 {
829         struct hvsi_struct *hp = tty->driver_data;
830         unsigned long flags;
831
832         pr_debug("%s\n", __func__);
833
834         tty_port_tty_set(&hp->port, NULL);
835
836         spin_lock_irqsave(&hp->lock, flags);
837         hp->port.count = 0;
838         hp->n_outbuf = 0;
839         spin_unlock_irqrestore(&hp->lock, flags);
840 }
841
842 /* called with hp->lock held */
843 static void hvsi_push(struct hvsi_struct *hp)
844 {
845         int n;
846
847         if (hp->n_outbuf <= 0)
848                 return;
849
850         n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf);
851         if (n > 0) {
852                 /* success */
853                 pr_debug("%s: wrote %i chars\n", __func__, n);
854                 hp->n_outbuf = 0;
855         } else if (n == -EIO) {
856                 __set_state(hp, HVSI_FSP_DIED);
857                 printk(KERN_ERR "hvsi%i: service processor died\n", hp->index);
858         }
859 }
860
861 /* hvsi_write_worker will keep rescheduling itself until outbuf is empty */
862 static void hvsi_write_worker(struct work_struct *work)
863 {
864         struct hvsi_struct *hp =
865                 container_of(work, struct hvsi_struct, writer.work);
866         unsigned long flags;
867 #ifdef DEBUG
868         static long start_j = 0;
869
870         if (start_j == 0)
871                 start_j = jiffies;
872 #endif /* DEBUG */
873
874         spin_lock_irqsave(&hp->lock, flags);
875
876         pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
877
878         if (!is_open(hp)) {
879                 /*
880                  * We could have a non-open connection if the service processor died
881                  * while we were busily scheduling ourselves. In that case, it could
882                  * be minutes before the service processor comes back, so only try
883                  * again once a second.
884                  */
885                 schedule_delayed_work(&hp->writer, HZ);
886                 goto out;
887         }
888
889         hvsi_push(hp);
890         if (hp->n_outbuf > 0)
891                 schedule_delayed_work(&hp->writer, 10);
892         else {
893 #ifdef DEBUG
894                 pr_debug("%s: outbuf emptied after %li jiffies\n", __func__,
895                                 jiffies - start_j);
896                 start_j = 0;
897 #endif /* DEBUG */
898                 wake_up_all(&hp->emptyq);
899                 tty_port_tty_wakeup(&hp->port);
900         }
901
902 out:
903         spin_unlock_irqrestore(&hp->lock, flags);
904 }
905
906 static int hvsi_write_room(struct tty_struct *tty)
907 {
908         struct hvsi_struct *hp = tty->driver_data;
909
910         return N_OUTBUF - hp->n_outbuf;
911 }
912
913 static int hvsi_chars_in_buffer(struct tty_struct *tty)
914 {
915         struct hvsi_struct *hp = tty->driver_data;
916
917         return hp->n_outbuf;
918 }
919
920 static int hvsi_write(struct tty_struct *tty,
921                      const unsigned char *buf, int count)
922 {
923         struct hvsi_struct *hp = tty->driver_data;
924         const char *source = buf;
925         unsigned long flags;
926         int total = 0;
927         int origcount = count;
928
929         spin_lock_irqsave(&hp->lock, flags);
930
931         pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
932
933         if (!is_open(hp)) {
934                 /* we're either closing or not yet open; don't accept data */
935                 pr_debug("%s: not open\n", __func__);
936                 goto out;
937         }
938
939         /*
940          * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf
941          * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls
942          * will see there is no room in outbuf and return.
943          */
944         while ((count > 0) && (hvsi_write_room(tty) > 0)) {
945                 int chunksize = min(count, hvsi_write_room(tty));
946
947                 BUG_ON(hp->n_outbuf < 0);
948                 memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
949                 hp->n_outbuf += chunksize;
950
951                 total += chunksize;
952                 source += chunksize;
953                 count -= chunksize;
954                 hvsi_push(hp);
955         }
956
957         if (hp->n_outbuf > 0) {
958                 /*
959                  * we weren't able to write it all to the hypervisor.
960                  * schedule another push attempt.
961                  */
962                 schedule_delayed_work(&hp->writer, 10);
963         }
964
965 out:
966         spin_unlock_irqrestore(&hp->lock, flags);
967
968         if (total != origcount)
969                 pr_debug("%s: wanted %i, only wrote %i\n", __func__, origcount,
970                         total);
971
972         return total;
973 }
974
975 /*
976  * I have never seen throttle or unthrottle called, so this little throttle
977  * buffering scheme may or may not work.
978  */
979 static void hvsi_throttle(struct tty_struct *tty)
980 {
981         struct hvsi_struct *hp = tty->driver_data;
982
983         pr_debug("%s\n", __func__);
984
985         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE);
986 }
987
988 static void hvsi_unthrottle(struct tty_struct *tty)
989 {
990         struct hvsi_struct *hp = tty->driver_data;
991         unsigned long flags;
992
993         pr_debug("%s\n", __func__);
994
995         spin_lock_irqsave(&hp->lock, flags);
996         if (hp->n_throttle) {
997                 hvsi_send_overflow(hp);
998                 tty_flip_buffer_push(&hp->port);
999         }
1000         spin_unlock_irqrestore(&hp->lock, flags);
1001
1002
1003         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
1004 }
1005
1006 static int hvsi_tiocmget(struct tty_struct *tty)
1007 {
1008         struct hvsi_struct *hp = tty->driver_data;
1009
1010         hvsi_get_mctrl(hp);
1011         return hp->mctrl;
1012 }
1013
1014 static int hvsi_tiocmset(struct tty_struct *tty,
1015                                 unsigned int set, unsigned int clear)
1016 {
1017         struct hvsi_struct *hp = tty->driver_data;
1018         unsigned long flags;
1019         uint16_t new_mctrl;
1020
1021         /* we can only alter DTR */
1022         clear &= TIOCM_DTR;
1023         set &= TIOCM_DTR;
1024
1025         spin_lock_irqsave(&hp->lock, flags);
1026
1027         new_mctrl = (hp->mctrl & ~clear) | set;
1028
1029         if (hp->mctrl != new_mctrl) {
1030                 hvsi_set_mctrl(hp, new_mctrl);
1031                 hp->mctrl = new_mctrl;
1032         }
1033         spin_unlock_irqrestore(&hp->lock, flags);
1034
1035         return 0;
1036 }
1037
1038
1039 static const struct tty_operations hvsi_ops = {
1040         .open = hvsi_open,
1041         .close = hvsi_close,
1042         .write = hvsi_write,
1043         .hangup = hvsi_hangup,
1044         .write_room = hvsi_write_room,
1045         .chars_in_buffer = hvsi_chars_in_buffer,
1046         .throttle = hvsi_throttle,
1047         .unthrottle = hvsi_unthrottle,
1048         .tiocmget = hvsi_tiocmget,
1049         .tiocmset = hvsi_tiocmset,
1050 };
1051
1052 static int __init hvsi_init(void)
1053 {
1054         int i, ret;
1055
1056         hvsi_driver = alloc_tty_driver(hvsi_count);
1057         if (!hvsi_driver)
1058                 return -ENOMEM;
1059
1060         hvsi_driver->driver_name = "hvsi";
1061         hvsi_driver->name = "hvsi";
1062         hvsi_driver->major = HVSI_MAJOR;
1063         hvsi_driver->minor_start = HVSI_MINOR;
1064         hvsi_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1065         hvsi_driver->init_termios = tty_std_termios;
1066         hvsi_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
1067         hvsi_driver->init_termios.c_ispeed = 9600;
1068         hvsi_driver->init_termios.c_ospeed = 9600;
1069         hvsi_driver->flags = TTY_DRIVER_REAL_RAW;
1070         tty_set_operations(hvsi_driver, &hvsi_ops);
1071
1072         for (i=0; i < hvsi_count; i++) {
1073                 struct hvsi_struct *hp = &hvsi_ports[i];
1074                 int ret = 1;
1075
1076                 tty_port_link_device(&hp->port, hvsi_driver, i);
1077
1078                 ret = request_irq(hp->virq, hvsi_interrupt, 0, "hvsi", hp);
1079                 if (ret)
1080                         printk(KERN_ERR "HVSI: couldn't reserve irq 0x%x (error %i)\n",
1081                                 hp->virq, ret);
1082         }
1083         hvsi_wait = wait_for_state; /* irqs active now */
1084
1085         ret = tty_register_driver(hvsi_driver);
1086         if (ret) {
1087                 pr_err("Couldn't register hvsi console driver\n");
1088                 goto err_free_irq;
1089         }
1090
1091         printk(KERN_DEBUG "HVSI: registered %i devices\n", hvsi_count);
1092
1093         return 0;
1094 err_free_irq:
1095         hvsi_wait = poll_for_state;
1096         for (i = 0; i < hvsi_count; i++) {
1097                 struct hvsi_struct *hp = &hvsi_ports[i];
1098
1099                 free_irq(hp->virq, hp);
1100         }
1101         tty_driver_kref_put(hvsi_driver);
1102
1103         return ret;
1104 }
1105 device_initcall(hvsi_init);
1106
1107 /***** console (not tty) code: *****/
1108
1109 static void hvsi_console_print(struct console *console, const char *buf,
1110                 unsigned int count)
1111 {
1112         struct hvsi_struct *hp = &hvsi_ports[console->index];
1113         char c[HVSI_MAX_OUTGOING_DATA] __ALIGNED__;
1114         unsigned int i = 0, n = 0;
1115         int ret, donecr = 0;
1116
1117         mb();
1118         if (!is_open(hp))
1119                 return;
1120
1121         /*
1122          * ugh, we have to translate LF -> CRLF ourselves, in place.
1123          * copied from hvc_console.c:
1124          */
1125         while (count > 0 || i > 0) {
1126                 if (count > 0 && i < sizeof(c)) {
1127                         if (buf[n] == '\n' && !donecr) {
1128                                 c[i++] = '\r';
1129                                 donecr = 1;
1130                         } else {
1131                                 c[i++] = buf[n++];
1132                                 donecr = 0;
1133                                 --count;
1134                         }
1135                 } else {
1136                         ret = hvsi_put_chars(hp, c, i);
1137                         if (ret < 0)
1138                                 i = 0;
1139                         i -= ret;
1140                 }
1141         }
1142 }
1143
1144 static struct tty_driver *hvsi_console_device(struct console *console,
1145         int *index)
1146 {
1147         *index = console->index;
1148         return hvsi_driver;
1149 }
1150
1151 static int __init hvsi_console_setup(struct console *console, char *options)
1152 {
1153         struct hvsi_struct *hp;
1154         int ret;
1155
1156         if (console->index < 0 || console->index >= hvsi_count)
1157                 return -1;
1158         hp = &hvsi_ports[console->index];
1159
1160         /* give the FSP a chance to change the baud rate when we re-open */
1161         hvsi_close_protocol(hp);
1162
1163         ret = hvsi_handshake(hp);
1164         if (ret < 0)
1165                 return ret;
1166
1167         ret = hvsi_get_mctrl(hp);
1168         if (ret < 0)
1169                 return ret;
1170
1171         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
1172         if (ret < 0)
1173                 return ret;
1174
1175         hp->flags |= HVSI_CONSOLE;
1176
1177         return 0;
1178 }
1179
1180 static struct console hvsi_console = {
1181         .name           = "hvsi",
1182         .write          = hvsi_console_print,
1183         .device         = hvsi_console_device,
1184         .setup          = hvsi_console_setup,
1185         .flags          = CON_PRINTBUFFER,
1186         .index          = -1,
1187 };
1188
1189 static int __init hvsi_console_init(void)
1190 {
1191         struct device_node *vty;
1192
1193         hvsi_wait = poll_for_state; /* no irqs yet; must poll */
1194
1195         /* search device tree for vty nodes */
1196         for_each_compatible_node(vty, "serial", "hvterm-protocol") {
1197                 struct hvsi_struct *hp;
1198                 const __be32 *vtermno, *irq;
1199
1200                 vtermno = of_get_property(vty, "reg", NULL);
1201                 irq = of_get_property(vty, "interrupts", NULL);
1202                 if (!vtermno || !irq)
1203                         continue;
1204
1205                 if (hvsi_count >= MAX_NR_HVSI_CONSOLES) {
1206                         of_node_put(vty);
1207                         break;
1208                 }
1209
1210                 hp = &hvsi_ports[hvsi_count];
1211                 INIT_DELAYED_WORK(&hp->writer, hvsi_write_worker);
1212                 INIT_WORK(&hp->handshaker, hvsi_handshaker);
1213                 init_waitqueue_head(&hp->emptyq);
1214                 init_waitqueue_head(&hp->stateq);
1215                 spin_lock_init(&hp->lock);
1216                 tty_port_init(&hp->port);
1217                 hp->index = hvsi_count;
1218                 hp->inbuf_end = hp->inbuf;
1219                 hp->state = HVSI_CLOSED;
1220                 hp->vtermno = be32_to_cpup(vtermno);
1221                 hp->virq = irq_create_mapping(NULL, be32_to_cpup(irq));
1222                 if (hp->virq == 0) {
1223                         printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
1224                                __func__, be32_to_cpup(irq));
1225                         tty_port_destroy(&hp->port);
1226                         continue;
1227                 }
1228
1229                 hvsi_count++;
1230         }
1231
1232         if (hvsi_count)
1233                 register_console(&hvsi_console);
1234         return 0;
1235 }
1236 console_initcall(hvsi_console_init);