ia64/linux-2.6.18-xen.hg

view drivers/char/hvsi.c @ 893:f994bfe9b93b

linux/blktap2: reduce TLB flush scope

c/s 885 added very coarse TLB flushing. Since these flushes always
follow single page updates, single page flushes (when available) are
sufficient.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
author Keir Fraser <keir.fraser@citrix.com>
date Thu Jun 04 10:32:57 2009 +0100 (2009-06-04)
parents 831230e53067
children
line source
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 */
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 */
32 #undef DEBUG
34 #include <linux/console.h>
35 #include <linux/ctype.h>
36 #include <linux/delay.h>
37 #include <linux/init.h>
38 #include <linux/interrupt.h>
39 #include <linux/module.h>
40 #include <linux/major.h>
41 #include <linux/kernel.h>
42 #include <linux/sched.h>
43 #include <linux/spinlock.h>
44 #include <linux/sysrq.h>
45 #include <linux/tty.h>
46 #include <linux/tty_flip.h>
47 #include <asm/hvcall.h>
48 #include <asm/hvconsole.h>
49 #include <asm/prom.h>
50 #include <asm/uaccess.h>
51 #include <asm/vio.h>
52 #include <asm/param.h>
54 #define HVSI_MAJOR 229
55 #define HVSI_MINOR 128
56 #define MAX_NR_HVSI_CONSOLES 4
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
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))))
71 struct hvsi_struct {
72 struct work_struct writer;
73 struct work_struct handshaker;
74 wait_queue_head_t emptyq; /* woken when outbuf is emptied */
75 wait_queue_head_t stateq; /* woken when HVSI state changes */
76 spinlock_t lock;
77 int index;
78 struct tty_struct *tty;
79 unsigned int count;
80 uint8_t throttle_buf[128];
81 uint8_t outbuf[N_OUTBUF]; /* to implement write_room and chars_in_buffer */
82 /* inbuf is for packet reassembly. leave a little room for leftovers. */
83 uint8_t inbuf[HVSI_MAX_PACKET + HVSI_MAX_READ];
84 uint8_t *inbuf_end;
85 int n_throttle;
86 int n_outbuf;
87 uint32_t vtermno;
88 uint32_t virq;
89 atomic_t seqno; /* HVSI packet sequence number */
90 uint16_t mctrl;
91 uint8_t state; /* HVSI protocol state */
92 uint8_t flags;
93 #ifdef CONFIG_MAGIC_SYSRQ
94 uint8_t sysrq;
95 #endif /* CONFIG_MAGIC_SYSRQ */
96 };
97 static struct hvsi_struct hvsi_ports[MAX_NR_HVSI_CONSOLES];
99 static struct tty_driver *hvsi_driver;
100 static int hvsi_count;
101 static int (*hvsi_wait)(struct hvsi_struct *hp, int state);
103 enum HVSI_PROTOCOL_STATE {
104 HVSI_CLOSED,
105 HVSI_WAIT_FOR_VER_RESPONSE,
106 HVSI_WAIT_FOR_VER_QUERY,
107 HVSI_OPEN,
108 HVSI_WAIT_FOR_MCTRL_RESPONSE,
109 HVSI_FSP_DIED,
110 };
111 #define HVSI_CONSOLE 0x1
113 #define VS_DATA_PACKET_HEADER 0xff
114 #define VS_CONTROL_PACKET_HEADER 0xfe
115 #define VS_QUERY_PACKET_HEADER 0xfd
116 #define VS_QUERY_RESPONSE_PACKET_HEADER 0xfc
118 /* control verbs */
119 #define VSV_SET_MODEM_CTL 1 /* to service processor only */
120 #define VSV_MODEM_CTL_UPDATE 2 /* from service processor only */
121 #define VSV_CLOSE_PROTOCOL 3
123 /* query verbs */
124 #define VSV_SEND_VERSION_NUMBER 1
125 #define VSV_SEND_MODEM_CTL_STATUS 2
127 /* yes, these masks are not consecutive. */
128 #define HVSI_TSDTR 0x01
129 #define HVSI_TSCD 0x20
131 struct hvsi_header {
132 uint8_t type;
133 uint8_t len;
134 uint16_t seqno;
135 } __attribute__((packed));
137 struct hvsi_data {
138 uint8_t type;
139 uint8_t len;
140 uint16_t seqno;
141 uint8_t data[HVSI_MAX_OUTGOING_DATA];
142 } __attribute__((packed));
144 struct hvsi_control {
145 uint8_t type;
146 uint8_t len;
147 uint16_t seqno;
148 uint16_t verb;
149 /* optional depending on verb: */
150 uint32_t word;
151 uint32_t mask;
152 } __attribute__((packed));
154 struct hvsi_query {
155 uint8_t type;
156 uint8_t len;
157 uint16_t seqno;
158 uint16_t verb;
159 } __attribute__((packed));
161 struct hvsi_query_response {
162 uint8_t type;
163 uint8_t len;
164 uint16_t seqno;
165 uint16_t verb;
166 uint16_t query_seqno;
167 union {
168 uint8_t version;
169 uint32_t mctrl_word;
170 } u;
171 } __attribute__((packed));
175 static inline int is_console(struct hvsi_struct *hp)
176 {
177 return hp->flags & HVSI_CONSOLE;
178 }
180 static inline int is_open(struct hvsi_struct *hp)
181 {
182 /* if we're waiting for an mctrl then we're already open */
183 return (hp->state == HVSI_OPEN)
184 || (hp->state == HVSI_WAIT_FOR_MCTRL_RESPONSE);
185 }
187 static inline void print_state(struct hvsi_struct *hp)
188 {
189 #ifdef DEBUG
190 static const char *state_names[] = {
191 "HVSI_CLOSED",
192 "HVSI_WAIT_FOR_VER_RESPONSE",
193 "HVSI_WAIT_FOR_VER_QUERY",
194 "HVSI_OPEN",
195 "HVSI_WAIT_FOR_MCTRL_RESPONSE",
196 "HVSI_FSP_DIED",
197 };
198 const char *name = state_names[hp->state];
200 if (hp->state > ARRAY_SIZE(state_names))
201 name = "UNKNOWN";
203 pr_debug("hvsi%i: state = %s\n", hp->index, name);
204 #endif /* DEBUG */
205 }
207 static inline void __set_state(struct hvsi_struct *hp, int state)
208 {
209 hp->state = state;
210 print_state(hp);
211 wake_up_all(&hp->stateq);
212 }
214 static inline void set_state(struct hvsi_struct *hp, int state)
215 {
216 unsigned long flags;
218 spin_lock_irqsave(&hp->lock, flags);
219 __set_state(hp, state);
220 spin_unlock_irqrestore(&hp->lock, flags);
221 }
223 static inline int len_packet(const uint8_t *packet)
224 {
225 return (int)((struct hvsi_header *)packet)->len;
226 }
228 static inline int is_header(const uint8_t *packet)
229 {
230 struct hvsi_header *header = (struct hvsi_header *)packet;
231 return header->type >= VS_QUERY_RESPONSE_PACKET_HEADER;
232 }
234 static inline int got_packet(const struct hvsi_struct *hp, uint8_t *packet)
235 {
236 if (hp->inbuf_end < packet + sizeof(struct hvsi_header))
237 return 0; /* don't even have the packet header */
239 if (hp->inbuf_end < (packet + len_packet(packet)))
240 return 0; /* don't have the rest of the packet */
242 return 1;
243 }
245 /* shift remaining bytes in packetbuf down */
246 static void compact_inbuf(struct hvsi_struct *hp, uint8_t *read_to)
247 {
248 int remaining = (int)(hp->inbuf_end - read_to);
250 pr_debug("%s: %i chars remain\n", __FUNCTION__, remaining);
252 if (read_to != hp->inbuf)
253 memmove(hp->inbuf, read_to, remaining);
255 hp->inbuf_end = hp->inbuf + remaining;
256 }
258 #ifdef DEBUG
259 #define dbg_dump_packet(packet) dump_packet(packet)
260 #define dbg_dump_hex(data, len) dump_hex(data, len)
261 #else
262 #define dbg_dump_packet(packet) do { } while (0)
263 #define dbg_dump_hex(data, len) do { } while (0)
264 #endif
266 static void dump_hex(const uint8_t *data, int len)
267 {
268 int i;
270 printk(" ");
271 for (i=0; i < len; i++)
272 printk("%.2x", data[i]);
274 printk("\n ");
275 for (i=0; i < len; i++) {
276 if (isprint(data[i]))
277 printk("%c", data[i]);
278 else
279 printk(".");
280 }
281 printk("\n");
282 }
284 static void dump_packet(uint8_t *packet)
285 {
286 struct hvsi_header *header = (struct hvsi_header *)packet;
288 printk("type 0x%x, len %i, seqno %i:\n", header->type, header->len,
289 header->seqno);
291 dump_hex(packet, header->len);
292 }
294 static int hvsi_read(struct hvsi_struct *hp, char *buf, int count)
295 {
296 unsigned long got;
298 got = hvc_get_chars(hp->vtermno, buf, count);
300 return got;
301 }
303 static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet,
304 struct tty_struct **to_hangup, struct hvsi_struct **to_handshake)
305 {
306 struct hvsi_control *header = (struct hvsi_control *)packet;
308 switch (header->verb) {
309 case VSV_MODEM_CTL_UPDATE:
310 if ((header->word & HVSI_TSCD) == 0) {
311 /* CD went away; no more connection */
312 pr_debug("hvsi%i: CD dropped\n", hp->index);
313 hp->mctrl &= TIOCM_CD;
314 /* If userland hasn't done an open(2) yet, hp->tty is NULL. */
315 if (hp->tty && !(hp->tty->flags & CLOCAL))
316 *to_hangup = hp->tty;
317 }
318 break;
319 case VSV_CLOSE_PROTOCOL:
320 pr_debug("hvsi%i: service processor came back\n", hp->index);
321 if (hp->state != HVSI_CLOSED) {
322 *to_handshake = hp;
323 }
324 break;
325 default:
326 printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ",
327 hp->index);
328 dump_packet(packet);
329 break;
330 }
331 }
333 static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet)
334 {
335 struct hvsi_query_response *resp = (struct hvsi_query_response *)packet;
337 switch (hp->state) {
338 case HVSI_WAIT_FOR_VER_RESPONSE:
339 __set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
340 break;
341 case HVSI_WAIT_FOR_MCTRL_RESPONSE:
342 hp->mctrl = 0;
343 if (resp->u.mctrl_word & HVSI_TSDTR)
344 hp->mctrl |= TIOCM_DTR;
345 if (resp->u.mctrl_word & HVSI_TSCD)
346 hp->mctrl |= TIOCM_CD;
347 __set_state(hp, HVSI_OPEN);
348 break;
349 default:
350 printk(KERN_ERR "hvsi%i: unexpected query response: ", hp->index);
351 dump_packet(packet);
352 break;
353 }
354 }
356 /* respond to service processor's version query */
357 static int hvsi_version_respond(struct hvsi_struct *hp, uint16_t query_seqno)
358 {
359 struct hvsi_query_response packet __ALIGNED__;
360 int wrote;
362 packet.type = VS_QUERY_RESPONSE_PACKET_HEADER;
363 packet.len = sizeof(struct hvsi_query_response);
364 packet.seqno = atomic_inc_return(&hp->seqno);
365 packet.verb = VSV_SEND_VERSION_NUMBER;
366 packet.u.version = HVSI_VERSION;
367 packet.query_seqno = query_seqno+1;
369 pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
370 dbg_dump_hex((uint8_t*)&packet, packet.len);
372 wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
373 if (wrote != packet.len) {
374 printk(KERN_ERR "hvsi%i: couldn't send query response!\n",
375 hp->index);
376 return -EIO;
377 }
379 return 0;
380 }
382 static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet)
383 {
384 struct hvsi_query *query = (struct hvsi_query *)packet;
386 switch (hp->state) {
387 case HVSI_WAIT_FOR_VER_QUERY:
388 hvsi_version_respond(hp, query->seqno);
389 __set_state(hp, HVSI_OPEN);
390 break;
391 default:
392 printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index);
393 dump_packet(packet);
394 break;
395 }
396 }
398 static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len)
399 {
400 int i;
402 for (i=0; i < len; i++) {
403 char c = buf[i];
404 #ifdef CONFIG_MAGIC_SYSRQ
405 if (c == '\0') {
406 hp->sysrq = 1;
407 continue;
408 } else if (hp->sysrq) {
409 handle_sysrq(c, NULL, hp->tty);
410 hp->sysrq = 0;
411 continue;
412 }
413 #endif /* CONFIG_MAGIC_SYSRQ */
414 tty_insert_flip_char(hp->tty, c, 0);
415 }
416 }
418 /*
419 * We could get 252 bytes of data at once here. But the tty layer only
420 * throttles us at TTY_THRESHOLD_THROTTLE (128) bytes, so we could overflow
421 * it. Accordingly we won't send more than 128 bytes at a time to the flip
422 * buffer, which will give the tty buffer a chance to throttle us. Should the
423 * value of TTY_THRESHOLD_THROTTLE change in n_tty.c, this code should be
424 * revisited.
425 */
426 #define TTY_THRESHOLD_THROTTLE 128
427 static struct tty_struct *hvsi_recv_data(struct hvsi_struct *hp,
428 const uint8_t *packet)
429 {
430 const struct hvsi_header *header = (const struct hvsi_header *)packet;
431 const uint8_t *data = packet + sizeof(struct hvsi_header);
432 int datalen = header->len - sizeof(struct hvsi_header);
433 int overflow = datalen - TTY_THRESHOLD_THROTTLE;
435 pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data);
437 if (datalen == 0)
438 return NULL;
440 if (overflow > 0) {
441 pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __FUNCTION__);
442 datalen = TTY_THRESHOLD_THROTTLE;
443 }
445 hvsi_insert_chars(hp, data, datalen);
447 if (overflow > 0) {
448 /*
449 * we still have more data to deliver, so we need to save off the
450 * overflow and send it later
451 */
452 pr_debug("%s: deferring overflow\n", __FUNCTION__);
453 memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow);
454 hp->n_throttle = overflow;
455 }
457 return hp->tty;
458 }
460 /*
461 * Returns true/false indicating data successfully read from hypervisor.
462 * Used both to get packets for tty connections and to advance the state
463 * machine during console handshaking (in which case tty = NULL and we ignore
464 * incoming data).
465 */
466 static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip,
467 struct tty_struct **hangup, struct hvsi_struct **handshake)
468 {
469 uint8_t *packet = hp->inbuf;
470 int chunklen;
472 *flip = NULL;
473 *hangup = NULL;
474 *handshake = NULL;
476 chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
477 if (chunklen == 0) {
478 pr_debug("%s: 0-length read\n", __FUNCTION__);
479 return 0;
480 }
482 pr_debug("%s: got %i bytes\n", __FUNCTION__, chunklen);
483 dbg_dump_hex(hp->inbuf_end, chunklen);
485 hp->inbuf_end += chunklen;
487 /* handle all completed packets */
488 while ((packet < hp->inbuf_end) && got_packet(hp, packet)) {
489 struct hvsi_header *header = (struct hvsi_header *)packet;
491 if (!is_header(packet)) {
492 printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index);
493 /* skip bytes until we find a header or run out of data */
494 while ((packet < hp->inbuf_end) && (!is_header(packet)))
495 packet++;
496 continue;
497 }
499 pr_debug("%s: handling %i-byte packet\n", __FUNCTION__,
500 len_packet(packet));
501 dbg_dump_packet(packet);
503 switch (header->type) {
504 case VS_DATA_PACKET_HEADER:
505 if (!is_open(hp))
506 break;
507 if (hp->tty == NULL)
508 break; /* no tty buffer to put data in */
509 *flip = hvsi_recv_data(hp, packet);
510 break;
511 case VS_CONTROL_PACKET_HEADER:
512 hvsi_recv_control(hp, packet, hangup, handshake);
513 break;
514 case VS_QUERY_RESPONSE_PACKET_HEADER:
515 hvsi_recv_response(hp, packet);
516 break;
517 case VS_QUERY_PACKET_HEADER:
518 hvsi_recv_query(hp, packet);
519 break;
520 default:
521 printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
522 hp->index, header->type);
523 dump_packet(packet);
524 break;
525 }
527 packet += len_packet(packet);
529 if (*hangup || *handshake) {
530 pr_debug("%s: hangup or handshake\n", __FUNCTION__);
531 /*
532 * we need to send the hangup now before receiving any more data.
533 * If we get "data, hangup, data", we can't deliver the second
534 * data before the hangup.
535 */
536 break;
537 }
538 }
540 compact_inbuf(hp, packet);
542 return 1;
543 }
545 static void hvsi_send_overflow(struct hvsi_struct *hp)
546 {
547 pr_debug("%s: delivering %i bytes overflow\n", __FUNCTION__,
548 hp->n_throttle);
550 hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);
551 hp->n_throttle = 0;
552 }
554 /*
555 * must get all pending data because we only get an irq on empty->non-empty
556 * transition
557 */
558 static irqreturn_t hvsi_interrupt(int irq, void *arg, struct pt_regs *regs)
559 {
560 struct hvsi_struct *hp = (struct hvsi_struct *)arg;
561 struct tty_struct *flip;
562 struct tty_struct *hangup;
563 struct hvsi_struct *handshake;
564 unsigned long flags;
565 int again = 1;
567 pr_debug("%s\n", __FUNCTION__);
569 while (again) {
570 spin_lock_irqsave(&hp->lock, flags);
571 again = hvsi_load_chunk(hp, &flip, &hangup, &handshake);
572 spin_unlock_irqrestore(&hp->lock, flags);
574 /*
575 * we have to call tty_flip_buffer_push() and tty_hangup() outside our
576 * spinlock. But we also have to keep going until we've read all the
577 * available data.
578 */
580 if (flip) {
581 /* there was data put in the tty flip buffer */
582 tty_flip_buffer_push(flip);
583 flip = NULL;
584 }
586 if (hangup) {
587 tty_hangup(hangup);
588 }
590 if (handshake) {
591 pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
592 schedule_work(&handshake->handshaker);
593 }
594 }
596 spin_lock_irqsave(&hp->lock, flags);
597 if (hp->tty && hp->n_throttle
598 && (!test_bit(TTY_THROTTLED, &hp->tty->flags))) {
599 /* we weren't hung up and we weren't throttled, so we can deliver the
600 * rest now */
601 flip = hp->tty;
602 hvsi_send_overflow(hp);
603 }
604 spin_unlock_irqrestore(&hp->lock, flags);
606 if (flip) {
607 tty_flip_buffer_push(flip);
608 }
610 return IRQ_HANDLED;
611 }
613 /* for boot console, before the irq handler is running */
614 static int __init poll_for_state(struct hvsi_struct *hp, int state)
615 {
616 unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
618 for (;;) {
619 hvsi_interrupt(hp->virq, (void *)hp, NULL); /* get pending data */
621 if (hp->state == state)
622 return 0;
624 mdelay(5);
625 if (time_after(jiffies, end_jiffies))
626 return -EIO;
627 }
628 }
630 /* wait for irq handler to change our state */
631 static int wait_for_state(struct hvsi_struct *hp, int state)
632 {
633 int ret = 0;
635 if (!wait_event_timeout(hp->stateq, (hp->state == state), HVSI_TIMEOUT))
636 ret = -EIO;
638 return ret;
639 }
641 static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
642 {
643 struct hvsi_query packet __ALIGNED__;
644 int wrote;
646 packet.type = VS_QUERY_PACKET_HEADER;
647 packet.len = sizeof(struct hvsi_query);
648 packet.seqno = atomic_inc_return(&hp->seqno);
649 packet.verb = verb;
651 pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
652 dbg_dump_hex((uint8_t*)&packet, packet.len);
654 wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
655 if (wrote != packet.len) {
656 printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
657 wrote);
658 return -EIO;
659 }
661 return 0;
662 }
664 static int hvsi_get_mctrl(struct hvsi_struct *hp)
665 {
666 int ret;
668 set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
669 hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
671 ret = hvsi_wait(hp, HVSI_OPEN);
672 if (ret < 0) {
673 printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
674 set_state(hp, HVSI_OPEN);
675 return ret;
676 }
678 pr_debug("%s: mctrl 0x%x\n", __FUNCTION__, hp->mctrl);
680 return 0;
681 }
683 /* note that we can only set DTR */
684 static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
685 {
686 struct hvsi_control packet __ALIGNED__;
687 int wrote;
689 packet.type = VS_CONTROL_PACKET_HEADER,
690 packet.seqno = atomic_inc_return(&hp->seqno);
691 packet.len = sizeof(struct hvsi_control);
692 packet.verb = VSV_SET_MODEM_CTL;
693 packet.mask = HVSI_TSDTR;
695 if (mctrl & TIOCM_DTR)
696 packet.word = HVSI_TSDTR;
698 pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
699 dbg_dump_hex((uint8_t*)&packet, packet.len);
701 wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
702 if (wrote != packet.len) {
703 printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
704 return -EIO;
705 }
707 return 0;
708 }
710 static void hvsi_drain_input(struct hvsi_struct *hp)
711 {
712 uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
713 unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
715 while (time_before(end_jiffies, jiffies))
716 if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
717 break;
718 }
720 static int hvsi_handshake(struct hvsi_struct *hp)
721 {
722 int ret;
724 /*
725 * We could have a CLOSE or other data waiting for us before we even try
726 * to open; try to throw it all away so we don't get confused. (CLOSE
727 * is the first message sent up the pipe when the FSP comes online. We
728 * need to distinguish between "it came up a while ago and we're the first
729 * user" and "it was just reset before it saw our handshake packet".)
730 */
731 hvsi_drain_input(hp);
733 set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
734 ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
735 if (ret < 0) {
736 printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
737 return ret;
738 }
740 ret = hvsi_wait(hp, HVSI_OPEN);
741 if (ret < 0)
742 return ret;
744 return 0;
745 }
747 static void hvsi_handshaker(void *arg)
748 {
749 struct hvsi_struct *hp = (struct hvsi_struct *)arg;
751 if (hvsi_handshake(hp) >= 0)
752 return;
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 }
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;
769 BUG_ON(count > HVSI_MAX_OUTGOING_DATA);
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);
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 }
784 static void hvsi_close_protocol(struct hvsi_struct *hp)
785 {
786 struct hvsi_control packet __ALIGNED__;
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;
793 pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
794 dbg_dump_hex((uint8_t*)&packet, packet.len);
796 hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
797 }
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;
806 pr_debug("%s\n", __FUNCTION__);
808 if (line < 0 || line >= hvsi_count)
809 return -ENODEV;
810 hp = &hvsi_ports[line];
812 tty->driver_data = hp;
813 tty->low_latency = 1; /* avoid throttle/tty_flip_buffer_push race */
815 mb();
816 if (hp->state == HVSI_FSP_DIED)
817 return -EIO;
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);
826 if (is_console(hp))
827 return 0; /* this has already been handshaked as the console */
829 ret = hvsi_handshake(hp);
830 if (ret < 0) {
831 printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
832 return ret;
833 }
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 }
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 }
847 return 0;
848 }
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);
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();
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 }
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;
871 pr_debug("%s\n", __FUNCTION__);
873 if (tty_hung_up_p(filp))
874 return;
876 spin_lock_irqsave(&hp->lock, flags);
878 if (--hp->count == 0) {
879 hp->tty = NULL;
880 hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
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;
892 spin_unlock_irqrestore(&hp->lock, flags);
894 /* let any existing irq handlers finish. no more will start. */
895 synchronize_irq(hp->virq);
897 /* hvsi_write_worker will re-schedule until outbuf is empty. */
898 hvsi_flush_output(hp);
900 /* tell FSP to stop sending data */
901 hvsi_close_protocol(hp);
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);
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);
915 spin_unlock_irqrestore(&hp->lock, flags);
916 }
918 static void hvsi_hangup(struct tty_struct *tty)
919 {
920 struct hvsi_struct *hp = tty->driver_data;
921 unsigned long flags;
923 pr_debug("%s\n", __FUNCTION__);
925 spin_lock_irqsave(&hp->lock, flags);
927 hp->count = 0;
928 hp->n_outbuf = 0;
929 hp->tty = NULL;
931 spin_unlock_irqrestore(&hp->lock, flags);
932 }
934 /* called with hp->lock held */
935 static void hvsi_push(struct hvsi_struct *hp)
936 {
937 int n;
939 if (hp->n_outbuf <= 0)
940 return;
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 }
953 /* hvsi_write_worker will keep rescheduling itself until outbuf is empty */
954 static void hvsi_write_worker(void *arg)
955 {
956 struct hvsi_struct *hp = (struct hvsi_struct *)arg;
957 unsigned long flags;
958 #ifdef DEBUG
959 static long start_j = 0;
961 if (start_j == 0)
962 start_j = jiffies;
963 #endif /* DEBUG */
965 spin_lock_irqsave(&hp->lock, flags);
967 pr_debug("%s: %i chars in buffer\n", __FUNCTION__, hp->n_outbuf);
969 if (!is_open(hp)) {
970 /*
971 * We could have a non-open connection if the service processor died
972 * while we were busily scheduling ourselves. In that case, it could
973 * be minutes before the service processor comes back, so only try
974 * again once a second.
975 */
976 schedule_delayed_work(&hp->writer, HZ);
977 goto out;
978 }
980 hvsi_push(hp);
981 if (hp->n_outbuf > 0)
982 schedule_delayed_work(&hp->writer, 10);
983 else {
984 #ifdef DEBUG
985 pr_debug("%s: outbuf emptied after %li jiffies\n", __FUNCTION__,
986 jiffies - start_j);
987 start_j = 0;
988 #endif /* DEBUG */
989 wake_up_all(&hp->emptyq);
990 tty_wakeup(hp->tty);
991 }
993 out:
994 spin_unlock_irqrestore(&hp->lock, flags);
995 }
997 static int hvsi_write_room(struct tty_struct *tty)
998 {
999 struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1001 return N_OUTBUF - hp->n_outbuf;
1004 static int hvsi_chars_in_buffer(struct tty_struct *tty)
1006 struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1008 return hp->n_outbuf;
1011 static int hvsi_write(struct tty_struct *tty,
1012 const unsigned char *buf, int count)
1014 struct hvsi_struct *hp = tty->driver_data;
1015 const char *source = buf;
1016 unsigned long flags;
1017 int total = 0;
1018 int origcount = count;
1020 spin_lock_irqsave(&hp->lock, flags);
1022 pr_debug("%s: %i chars in buffer\n", __FUNCTION__, hp->n_outbuf);
1024 if (!is_open(hp)) {
1025 /* we're either closing or not yet open; don't accept data */
1026 pr_debug("%s: not open\n", __FUNCTION__);
1027 goto out;
1030 /*
1031 * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf
1032 * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls
1033 * will see there is no room in outbuf and return.
1034 */
1035 while ((count > 0) && (hvsi_write_room(hp->tty) > 0)) {
1036 int chunksize = min(count, hvsi_write_room(hp->tty));
1038 BUG_ON(hp->n_outbuf < 0);
1039 memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
1040 hp->n_outbuf += chunksize;
1042 total += chunksize;
1043 source += chunksize;
1044 count -= chunksize;
1045 hvsi_push(hp);
1048 if (hp->n_outbuf > 0) {
1049 /*
1050 * we weren't able to write it all to the hypervisor.
1051 * schedule another push attempt.
1052 */
1053 schedule_delayed_work(&hp->writer, 10);
1056 out:
1057 spin_unlock_irqrestore(&hp->lock, flags);
1059 if (total != origcount)
1060 pr_debug("%s: wanted %i, only wrote %i\n", __FUNCTION__, origcount,
1061 total);
1063 return total;
1066 /*
1067 * I have never seen throttle or unthrottle called, so this little throttle
1068 * buffering scheme may or may not work.
1069 */
1070 static void hvsi_throttle(struct tty_struct *tty)
1072 struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1074 pr_debug("%s\n", __FUNCTION__);
1076 h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE);
1079 static void hvsi_unthrottle(struct tty_struct *tty)
1081 struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1082 unsigned long flags;
1083 int shouldflip = 0;
1085 pr_debug("%s\n", __FUNCTION__);
1087 spin_lock_irqsave(&hp->lock, flags);
1088 if (hp->n_throttle) {
1089 hvsi_send_overflow(hp);
1090 shouldflip = 1;
1092 spin_unlock_irqrestore(&hp->lock, flags);
1094 if (shouldflip)
1095 tty_flip_buffer_push(hp->tty);
1097 h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
1100 static int hvsi_tiocmget(struct tty_struct *tty, struct file *file)
1102 struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1104 hvsi_get_mctrl(hp);
1105 return hp->mctrl;
1108 static int hvsi_tiocmset(struct tty_struct *tty, struct file *file,
1109 unsigned int set, unsigned int clear)
1111 struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1112 unsigned long flags;
1113 uint16_t new_mctrl;
1115 /* we can only alter DTR */
1116 clear &= TIOCM_DTR;
1117 set &= TIOCM_DTR;
1119 spin_lock_irqsave(&hp->lock, flags);
1121 new_mctrl = (hp->mctrl & ~clear) | set;
1123 if (hp->mctrl != new_mctrl) {
1124 hvsi_set_mctrl(hp, new_mctrl);
1125 hp->mctrl = new_mctrl;
1127 spin_unlock_irqrestore(&hp->lock, flags);
1129 return 0;
1133 static struct tty_operations hvsi_ops = {
1134 .open = hvsi_open,
1135 .close = hvsi_close,
1136 .write = hvsi_write,
1137 .hangup = hvsi_hangup,
1138 .write_room = hvsi_write_room,
1139 .chars_in_buffer = hvsi_chars_in_buffer,
1140 .throttle = hvsi_throttle,
1141 .unthrottle = hvsi_unthrottle,
1142 .tiocmget = hvsi_tiocmget,
1143 .tiocmset = hvsi_tiocmset,
1144 };
1146 static int __init hvsi_init(void)
1148 int i;
1150 hvsi_driver = alloc_tty_driver(hvsi_count);
1151 if (!hvsi_driver)
1152 return -ENOMEM;
1154 hvsi_driver->owner = THIS_MODULE;
1155 hvsi_driver->driver_name = "hvsi";
1156 hvsi_driver->name = "hvsi";
1157 hvsi_driver->major = HVSI_MAJOR;
1158 hvsi_driver->minor_start = HVSI_MINOR;
1159 hvsi_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1160 hvsi_driver->init_termios = tty_std_termios;
1161 hvsi_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
1162 hvsi_driver->flags = TTY_DRIVER_REAL_RAW;
1163 tty_set_operations(hvsi_driver, &hvsi_ops);
1165 for (i=0; i < hvsi_count; i++) {
1166 struct hvsi_struct *hp = &hvsi_ports[i];
1167 int ret = 1;
1169 ret = request_irq(hp->virq, hvsi_interrupt, IRQF_DISABLED, "hvsi", hp);
1170 if (ret)
1171 printk(KERN_ERR "HVSI: couldn't reserve irq 0x%x (error %i)\n",
1172 hp->virq, ret);
1174 hvsi_wait = wait_for_state; /* irqs active now */
1176 if (tty_register_driver(hvsi_driver))
1177 panic("Couldn't register hvsi console driver\n");
1179 printk(KERN_DEBUG "HVSI: registered %i devices\n", hvsi_count);
1181 return 0;
1183 device_initcall(hvsi_init);
1185 /***** console (not tty) code: *****/
1187 static void hvsi_console_print(struct console *console, const char *buf,
1188 unsigned int count)
1190 struct hvsi_struct *hp = &hvsi_ports[console->index];
1191 char c[HVSI_MAX_OUTGOING_DATA] __ALIGNED__;
1192 unsigned int i = 0, n = 0;
1193 int ret, donecr = 0;
1195 mb();
1196 if (!is_open(hp))
1197 return;
1199 /*
1200 * ugh, we have to translate LF -> CRLF ourselves, in place.
1201 * copied from hvc_console.c:
1202 */
1203 while (count > 0 || i > 0) {
1204 if (count > 0 && i < sizeof(c)) {
1205 if (buf[n] == '\n' && !donecr) {
1206 c[i++] = '\r';
1207 donecr = 1;
1208 } else {
1209 c[i++] = buf[n++];
1210 donecr = 0;
1211 --count;
1213 } else {
1214 ret = hvsi_put_chars(hp, c, i);
1215 if (ret < 0)
1216 i = 0;
1217 i -= ret;
1222 static struct tty_driver *hvsi_console_device(struct console *console,
1223 int *index)
1225 *index = console->index;
1226 return hvsi_driver;
1229 static int __init hvsi_console_setup(struct console *console, char *options)
1231 struct hvsi_struct *hp = &hvsi_ports[console->index];
1232 int ret;
1234 if (console->index < 0 || console->index >= hvsi_count)
1235 return -1;
1237 /* give the FSP a chance to change the baud rate when we re-open */
1238 hvsi_close_protocol(hp);
1240 ret = hvsi_handshake(hp);
1241 if (ret < 0)
1242 return ret;
1244 ret = hvsi_get_mctrl(hp);
1245 if (ret < 0)
1246 return ret;
1248 ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
1249 if (ret < 0)
1250 return ret;
1252 hp->flags |= HVSI_CONSOLE;
1254 return 0;
1257 static struct console hvsi_con_driver = {
1258 .name = "hvsi",
1259 .write = hvsi_console_print,
1260 .device = hvsi_console_device,
1261 .setup = hvsi_console_setup,
1262 .flags = CON_PRINTBUFFER,
1263 .index = -1,
1264 };
1266 static int __init hvsi_console_init(void)
1268 struct device_node *vty;
1270 hvsi_wait = poll_for_state; /* no irqs yet; must poll */
1272 /* search device tree for vty nodes */
1273 for (vty = of_find_compatible_node(NULL, "serial", "hvterm-protocol");
1274 vty != NULL;
1275 vty = of_find_compatible_node(vty, "serial", "hvterm-protocol")) {
1276 struct hvsi_struct *hp;
1277 uint32_t *vtermno;
1278 uint32_t *irq;
1280 vtermno = (uint32_t *)get_property(vty, "reg", NULL);
1281 irq = (uint32_t *)get_property(vty, "interrupts", NULL);
1282 if (!vtermno || !irq)
1283 continue;
1285 if (hvsi_count >= MAX_NR_HVSI_CONSOLES) {
1286 of_node_put(vty);
1287 break;
1290 hp = &hvsi_ports[hvsi_count];
1291 INIT_WORK(&hp->writer, hvsi_write_worker, hp);
1292 INIT_WORK(&hp->handshaker, hvsi_handshaker, hp);
1293 init_waitqueue_head(&hp->emptyq);
1294 init_waitqueue_head(&hp->stateq);
1295 spin_lock_init(&hp->lock);
1296 hp->index = hvsi_count;
1297 hp->inbuf_end = hp->inbuf;
1298 hp->state = HVSI_CLOSED;
1299 hp->vtermno = *vtermno;
1300 hp->virq = irq_create_mapping(NULL, irq[0]);
1301 if (hp->virq == NO_IRQ) {
1302 printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
1303 __FUNCTION__, irq[0]);
1304 continue;
1307 hvsi_count++;
1310 if (hvsi_count)
1311 register_console(&hvsi_con_driver);
1312 return 0;
1314 console_initcall(hvsi_console_init);