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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (C) 2004 Hollis Blanchard <hollisb@us.ibm.com>, IBM
4 */
5
6/* Host Virtual Serial Interface (HVSI) is a protocol between the hosted OS
7 * and the service processor on IBM pSeries servers. On these servers, there
8 * are no serial ports under the OS's control, and sometimes there is no other
9 * console available either. However, the service processor has two standard
10 * serial ports, so this over-complicated protocol allows the OS to control
11 * those ports by proxy.
12 *
13 * Besides data, the procotol supports the reading/writing of the serial
14 * port's DTR line, and the reading of the CD line. This is to allow the OS to
15 * control a modem attached to the service processor's serial port. Note that
16 * the OS cannot change the speed of the port through this protocol.
17 */
18
19#undef DEBUG
20
21#include <linux/console.h>
22#include <linux/ctype.h>
23#include <linux/delay.h>
24#include <linux/init.h>
25#include <linux/interrupt.h>
26#include <linux/module.h>
27#include <linux/major.h>
28#include <linux/kernel.h>
29#include <linux/of_irq.h>
30#include <linux/spinlock.h>
31#include <linux/sysrq.h>
32#include <linux/tty.h>
33#include <linux/tty_flip.h>
34#include <asm/hvcall.h>
35#include <asm/hvconsole.h>
36#include <linux/uaccess.h>
37#include <asm/vio.h>
38#include <asm/param.h>
39#include <asm/hvsi.h>
40
41#define HVSI_MAJOR 229
42#define HVSI_MINOR 128
43#define MAX_NR_HVSI_CONSOLES 4
44
45#define HVSI_TIMEOUT (5*HZ)
46#define HVSI_VERSION 1
47#define HVSI_MAX_PACKET 256
48#define HVSI_MAX_READ 16
49#define HVSI_MAX_OUTGOING_DATA 12
50#define N_OUTBUF 12
51
52/*
53 * we pass data via two 8-byte registers, so we would like our char arrays
54 * properly aligned for those loads.
55 */
56#define __ALIGNED__ __attribute__((__aligned__(sizeof(long))))
57
58struct hvsi_struct {
59 struct tty_port port;
60 struct delayed_work writer;
61 struct work_struct handshaker;
62 wait_queue_head_t emptyq; /* woken when outbuf is emptied */
63 wait_queue_head_t stateq; /* woken when HVSI state changes */
64 spinlock_t lock;
65 int index;
66 uint8_t throttle_buf[128];
67 uint8_t outbuf[N_OUTBUF]; /* to implement write_room and chars_in_buffer */
68 /* inbuf is for packet reassembly. leave a little room for leftovers. */
69 uint8_t inbuf[HVSI_MAX_PACKET + HVSI_MAX_READ];
70 uint8_t *inbuf_end;
71 int n_throttle;
72 int n_outbuf;
73 uint32_t vtermno;
74 uint32_t virq;
75 atomic_t seqno; /* HVSI packet sequence number */
76 uint16_t mctrl;
77 uint8_t state; /* HVSI protocol state */
78 uint8_t flags;
79#ifdef CONFIG_MAGIC_SYSRQ
80 uint8_t sysrq;
81#endif /* CONFIG_MAGIC_SYSRQ */
82};
83static struct hvsi_struct hvsi_ports[MAX_NR_HVSI_CONSOLES];
84
85static struct tty_driver *hvsi_driver;
86static int hvsi_count;
87static int (*hvsi_wait)(struct hvsi_struct *hp, int state);
88
89enum HVSI_PROTOCOL_STATE {
90 HVSI_CLOSED,
91 HVSI_WAIT_FOR_VER_RESPONSE,
92 HVSI_WAIT_FOR_VER_QUERY,
93 HVSI_OPEN,
94 HVSI_WAIT_FOR_MCTRL_RESPONSE,
95 HVSI_FSP_DIED,
96};
97#define HVSI_CONSOLE 0x1
98
99static inline int is_console(struct hvsi_struct *hp)
100{
101 return hp->flags & HVSI_CONSOLE;
102}
103
104static inline int is_open(struct hvsi_struct *hp)
105{
106 /* if we're waiting for an mctrl then we're already open */
107 return (hp->state == HVSI_OPEN)
108 || (hp->state == HVSI_WAIT_FOR_MCTRL_RESPONSE);
109}
110
111static inline void print_state(struct hvsi_struct *hp)
112{
113#ifdef DEBUG
114 static const char *state_names[] = {
115 "HVSI_CLOSED",
116 "HVSI_WAIT_FOR_VER_RESPONSE",
117 "HVSI_WAIT_FOR_VER_QUERY",
118 "HVSI_OPEN",
119 "HVSI_WAIT_FOR_MCTRL_RESPONSE",
120 "HVSI_FSP_DIED",
121 };
122 const char *name = (hp->state < ARRAY_SIZE(state_names))
123 ? state_names[hp->state] : "UNKNOWN";
124
125 pr_debug("hvsi%i: state = %s\n", hp->index, name);
126#endif /* DEBUG */
127}
128
129static inline void __set_state(struct hvsi_struct *hp, int state)
130{
131 hp->state = state;
132 print_state(hp);
133 wake_up_all(&hp->stateq);
134}
135
136static inline void set_state(struct hvsi_struct *hp, int state)
137{
138 unsigned long flags;
139
140 spin_lock_irqsave(&hp->lock, flags);
141 __set_state(hp, state);
142 spin_unlock_irqrestore(&hp->lock, flags);
143}
144
145static inline int len_packet(const uint8_t *packet)
146{
147 return (int)((struct hvsi_header *)packet)->len;
148}
149
150static inline int is_header(const uint8_t *packet)
151{
152 struct hvsi_header *header = (struct hvsi_header *)packet;
153 return header->type >= VS_QUERY_RESPONSE_PACKET_HEADER;
154}
155
156static inline int got_packet(const struct hvsi_struct *hp, uint8_t *packet)
157{
158 if (hp->inbuf_end < packet + sizeof(struct hvsi_header))
159 return 0; /* don't even have the packet header */
160
161 if (hp->inbuf_end < (packet + len_packet(packet)))
162 return 0; /* don't have the rest of the packet */
163
164 return 1;
165}
166
167/* shift remaining bytes in packetbuf down */
168static void compact_inbuf(struct hvsi_struct *hp, uint8_t *read_to)
169{
170 int remaining = (int)(hp->inbuf_end - read_to);
171
172 pr_debug("%s: %i chars remain\n", __func__, remaining);
173
174 if (read_to != hp->inbuf)
175 memmove(hp->inbuf, read_to, remaining);
176
177 hp->inbuf_end = hp->inbuf + remaining;
178}
179
180#ifdef DEBUG
181#define dbg_dump_packet(packet) dump_packet(packet)
182#define dbg_dump_hex(data, len) dump_hex(data, len)
183#else
184#define dbg_dump_packet(packet) do { } while (0)
185#define dbg_dump_hex(data, len) do { } while (0)
186#endif
187
188static void dump_hex(const uint8_t *data, int len)
189{
190 int i;
191
192 printk(" ");
193 for (i=0; i < len; i++)
194 printk("%.2x", data[i]);
195
196 printk("\n ");
197 for (i=0; i < len; i++) {
198 if (isprint(data[i]))
199 printk("%c", data[i]);
200 else
201 printk(".");
202 }
203 printk("\n");
204}
205
206static void dump_packet(uint8_t *packet)
207{
208 struct hvsi_header *header = (struct hvsi_header *)packet;
209
210 printk("type 0x%x, len %i, seqno %i:\n", header->type, header->len,
211 header->seqno);
212
213 dump_hex(packet, header->len);
214}
215
216static int hvsi_read(struct hvsi_struct *hp, char *buf, int count)
217{
218 unsigned long got;
219
220 got = hvc_get_chars(hp->vtermno, buf, count);
221
222 return got;
223}
224
225static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet,
226 struct tty_struct *tty, struct hvsi_struct **to_handshake)
227{
228 struct hvsi_control *header = (struct hvsi_control *)packet;
229
230 switch (be16_to_cpu(header->verb)) {
231 case VSV_MODEM_CTL_UPDATE:
232 if ((be32_to_cpu(header->word) & HVSI_TSCD) == 0) {
233 /* CD went away; no more connection */
234 pr_debug("hvsi%i: CD dropped\n", hp->index);
235 hp->mctrl &= TIOCM_CD;
236 if (tty && !C_CLOCAL(tty))
237 tty_hangup(tty);
238 }
239 break;
240 case VSV_CLOSE_PROTOCOL:
241 pr_debug("hvsi%i: service processor came back\n", hp->index);
242 if (hp->state != HVSI_CLOSED) {
243 *to_handshake = hp;
244 }
245 break;
246 default:
247 printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ",
248 hp->index);
249 dump_packet(packet);
250 break;
251 }
252}
253
254static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet)
255{
256 struct hvsi_query_response *resp = (struct hvsi_query_response *)packet;
257 uint32_t mctrl_word;
258
259 switch (hp->state) {
260 case HVSI_WAIT_FOR_VER_RESPONSE:
261 __set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
262 break;
263 case HVSI_WAIT_FOR_MCTRL_RESPONSE:
264 hp->mctrl = 0;
265 mctrl_word = be32_to_cpu(resp->u.mctrl_word);
266 if (mctrl_word & HVSI_TSDTR)
267 hp->mctrl |= TIOCM_DTR;
268 if (mctrl_word & HVSI_TSCD)
269 hp->mctrl |= TIOCM_CD;
270 __set_state(hp, HVSI_OPEN);
271 break;
272 default:
273 printk(KERN_ERR "hvsi%i: unexpected query response: ", hp->index);
274 dump_packet(packet);
275 break;
276 }
277}
278
279/* respond to service processor's version query */
280static int hvsi_version_respond(struct hvsi_struct *hp, uint16_t query_seqno)
281{
282 struct hvsi_query_response packet __ALIGNED__;
283 int wrote;
284
285 packet.hdr.type = VS_QUERY_RESPONSE_PACKET_HEADER;
286 packet.hdr.len = sizeof(struct hvsi_query_response);
287 packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno));
288 packet.verb = cpu_to_be16(VSV_SEND_VERSION_NUMBER);
289 packet.u.version = HVSI_VERSION;
290 packet.query_seqno = cpu_to_be16(query_seqno+1);
291
292 pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
293 dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
294
295 wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
296 if (wrote != packet.hdr.len) {
297 printk(KERN_ERR "hvsi%i: couldn't send query response!\n",
298 hp->index);
299 return -EIO;
300 }
301
302 return 0;
303}
304
305static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet)
306{
307 struct hvsi_query *query = (struct hvsi_query *)packet;
308
309 switch (hp->state) {
310 case HVSI_WAIT_FOR_VER_QUERY:
311 hvsi_version_respond(hp, be16_to_cpu(query->hdr.seqno));
312 __set_state(hp, HVSI_OPEN);
313 break;
314 default:
315 printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index);
316 dump_packet(packet);
317 break;
318 }
319}
320
321static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len)
322{
323 int i;
324
325 for (i=0; i < len; i++) {
326 char c = buf[i];
327#ifdef CONFIG_MAGIC_SYSRQ
328 if (c == '\0') {
329 hp->sysrq = 1;
330 continue;
331 } else if (hp->sysrq) {
332 handle_sysrq(c);
333 hp->sysrq = 0;
334 continue;
335 }
336#endif /* CONFIG_MAGIC_SYSRQ */
337 tty_insert_flip_char(&hp->port, c, 0);
338 }
339}
340
341/*
342 * We could get 252 bytes of data at once here. But the tty layer only
343 * throttles us at TTY_THRESHOLD_THROTTLE (128) bytes, so we could overflow
344 * it. Accordingly we won't send more than 128 bytes at a time to the flip
345 * buffer, which will give the tty buffer a chance to throttle us. Should the
346 * value of TTY_THRESHOLD_THROTTLE change in n_tty.c, this code should be
347 * revisited.
348 */
349#define TTY_THRESHOLD_THROTTLE 128
350static bool hvsi_recv_data(struct hvsi_struct *hp, const uint8_t *packet)
351{
352 const struct hvsi_header *header = (const struct hvsi_header *)packet;
353 const uint8_t *data = packet + sizeof(struct hvsi_header);
354 int datalen = header->len - sizeof(struct hvsi_header);
355 int overflow = datalen - TTY_THRESHOLD_THROTTLE;
356
357 pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data);
358
359 if (datalen == 0)
360 return false;
361
362 if (overflow > 0) {
363 pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __func__);
364 datalen = TTY_THRESHOLD_THROTTLE;
365 }
366
367 hvsi_insert_chars(hp, data, datalen);
368
369 if (overflow > 0) {
370 /*
371 * we still have more data to deliver, so we need to save off the
372 * overflow and send it later
373 */
374 pr_debug("%s: deferring overflow\n", __func__);
375 memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow);
376 hp->n_throttle = overflow;
377 }
378
379 return true;
380}
381
382/*
383 * Returns true/false indicating data successfully read from hypervisor.
384 * Used both to get packets for tty connections and to advance the state
385 * machine during console handshaking (in which case tty = NULL and we ignore
386 * incoming data).
387 */
388static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct *tty,
389 struct hvsi_struct **handshake)
390{
391 uint8_t *packet = hp->inbuf;
392 int chunklen;
393 bool flip = false;
394
395 *handshake = NULL;
396
397 chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
398 if (chunklen == 0) {
399 pr_debug("%s: 0-length read\n", __func__);
400 return 0;
401 }
402
403 pr_debug("%s: got %i bytes\n", __func__, chunklen);
404 dbg_dump_hex(hp->inbuf_end, chunklen);
405
406 hp->inbuf_end += chunklen;
407
408 /* handle all completed packets */
409 while ((packet < hp->inbuf_end) && got_packet(hp, packet)) {
410 struct hvsi_header *header = (struct hvsi_header *)packet;
411
412 if (!is_header(packet)) {
413 printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index);
414 /* skip bytes until we find a header or run out of data */
415 while ((packet < hp->inbuf_end) && (!is_header(packet)))
416 packet++;
417 continue;
418 }
419
420 pr_debug("%s: handling %i-byte packet\n", __func__,
421 len_packet(packet));
422 dbg_dump_packet(packet);
423
424 switch (header->type) {
425 case VS_DATA_PACKET_HEADER:
426 if (!is_open(hp))
427 break;
428 flip = hvsi_recv_data(hp, packet);
429 break;
430 case VS_CONTROL_PACKET_HEADER:
431 hvsi_recv_control(hp, packet, tty, handshake);
432 break;
433 case VS_QUERY_RESPONSE_PACKET_HEADER:
434 hvsi_recv_response(hp, packet);
435 break;
436 case VS_QUERY_PACKET_HEADER:
437 hvsi_recv_query(hp, packet);
438 break;
439 default:
440 printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
441 hp->index, header->type);
442 dump_packet(packet);
443 break;
444 }
445
446 packet += len_packet(packet);
447
448 if (*handshake) {
449 pr_debug("%s: handshake\n", __func__);
450 break;
451 }
452 }
453
454 compact_inbuf(hp, packet);
455
456 if (flip)
457 tty_flip_buffer_push(&hp->port);
458
459 return 1;
460}
461
462static void hvsi_send_overflow(struct hvsi_struct *hp)
463{
464 pr_debug("%s: delivering %i bytes overflow\n", __func__,
465 hp->n_throttle);
466
467 hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);
468 hp->n_throttle = 0;
469}
470
471/*
472 * must get all pending data because we only get an irq on empty->non-empty
473 * transition
474 */
475static irqreturn_t hvsi_interrupt(int irq, void *arg)
476{
477 struct hvsi_struct *hp = (struct hvsi_struct *)arg;
478 struct hvsi_struct *handshake;
479 struct tty_struct *tty;
480 unsigned long flags;
481 int again = 1;
482
483 pr_debug("%s\n", __func__);
484
485 tty = tty_port_tty_get(&hp->port);
486
487 while (again) {
488 spin_lock_irqsave(&hp->lock, flags);
489 again = hvsi_load_chunk(hp, tty, &handshake);
490 spin_unlock_irqrestore(&hp->lock, flags);
491
492 if (handshake) {
493 pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
494 schedule_work(&handshake->handshaker);
495 }
496 }
497
498 spin_lock_irqsave(&hp->lock, flags);
499 if (tty && hp->n_throttle && !tty_throttled(tty)) {
500 /* we weren't hung up and we weren't throttled, so we can
501 * deliver the rest now */
502 hvsi_send_overflow(hp);
503 tty_flip_buffer_push(&hp->port);
504 }
505 spin_unlock_irqrestore(&hp->lock, flags);
506
507 tty_kref_put(tty);
508
509 return IRQ_HANDLED;
510}
511
512/* for boot console, before the irq handler is running */
513static int __init poll_for_state(struct hvsi_struct *hp, int state)
514{
515 unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
516
517 for (;;) {
518 hvsi_interrupt(hp->virq, (void *)hp); /* get pending data */
519
520 if (hp->state == state)
521 return 0;
522
523 mdelay(5);
524 if (time_after(jiffies, end_jiffies))
525 return -EIO;
526 }
527}
528
529/* wait for irq handler to change our state */
530static int wait_for_state(struct hvsi_struct *hp, int state)
531{
532 int ret = 0;
533
534 if (!wait_event_timeout(hp->stateq, (hp->state == state), HVSI_TIMEOUT))
535 ret = -EIO;
536
537 return ret;
538}
539
540static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
541{
542 struct hvsi_query packet __ALIGNED__;
543 int wrote;
544
545 packet.hdr.type = VS_QUERY_PACKET_HEADER;
546 packet.hdr.len = sizeof(struct hvsi_query);
547 packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno));
548 packet.verb = cpu_to_be16(verb);
549
550 pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
551 dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
552
553 wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
554 if (wrote != packet.hdr.len) {
555 printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
556 wrote);
557 return -EIO;
558 }
559
560 return 0;
561}
562
563static int hvsi_get_mctrl(struct hvsi_struct *hp)
564{
565 int ret;
566
567 set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
568 hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
569
570 ret = hvsi_wait(hp, HVSI_OPEN);
571 if (ret < 0) {
572 printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
573 set_state(hp, HVSI_OPEN);
574 return ret;
575 }
576
577 pr_debug("%s: mctrl 0x%x\n", __func__, hp->mctrl);
578
579 return 0;
580}
581
582/* note that we can only set DTR */
583static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
584{
585 struct hvsi_control packet __ALIGNED__;
586 int wrote;
587
588 packet.hdr.type = VS_CONTROL_PACKET_HEADER;
589 packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno));
590 packet.hdr.len = sizeof(struct hvsi_control);
591 packet.verb = cpu_to_be16(VSV_SET_MODEM_CTL);
592 packet.mask = cpu_to_be32(HVSI_TSDTR);
593
594 if (mctrl & TIOCM_DTR)
595 packet.word = cpu_to_be32(HVSI_TSDTR);
596
597 pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
598 dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
599
600 wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
601 if (wrote != packet.hdr.len) {
602 printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
603 return -EIO;
604 }
605
606 return 0;
607}
608
609static void hvsi_drain_input(struct hvsi_struct *hp)
610{
611 uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
612 unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
613
614 while (time_before(end_jiffies, jiffies))
615 if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
616 break;
617}
618
619static int hvsi_handshake(struct hvsi_struct *hp)
620{
621 int ret;
622
623 /*
624 * We could have a CLOSE or other data waiting for us before we even try
625 * to open; try to throw it all away so we don't get confused. (CLOSE
626 * is the first message sent up the pipe when the FSP comes online. We
627 * need to distinguish between "it came up a while ago and we're the first
628 * user" and "it was just reset before it saw our handshake packet".)
629 */
630 hvsi_drain_input(hp);
631
632 set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
633 ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
634 if (ret < 0) {
635 printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
636 return ret;
637 }
638
639 ret = hvsi_wait(hp, HVSI_OPEN);
640 if (ret < 0)
641 return ret;
642
643 return 0;
644}
645
646static void hvsi_handshaker(struct work_struct *work)
647{
648 struct hvsi_struct *hp =
649 container_of(work, struct hvsi_struct, handshaker);
650
651 if (hvsi_handshake(hp) >= 0)
652 return;
653
654 printk(KERN_ERR "hvsi%i: re-handshaking failed\n", hp->index);
655 if (is_console(hp)) {
656 /*
657 * ttys will re-attempt the handshake via hvsi_open, but
658 * the console will not.
659 */
660 printk(KERN_ERR "hvsi%i: lost console!\n", hp->index);
661 }
662}
663
664static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
665{
666 struct hvsi_data packet __ALIGNED__;
667 int ret;
668
669 BUG_ON(count > HVSI_MAX_OUTGOING_DATA);
670
671 packet.hdr.type = VS_DATA_PACKET_HEADER;
672 packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno));
673 packet.hdr.len = count + sizeof(struct hvsi_header);
674 memcpy(&packet.data, buf, count);
675
676 ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
677 if (ret == packet.hdr.len) {
678 /* return the number of chars written, not the packet length */
679 return count;
680 }
681 return ret; /* return any errors */
682}
683
684static void hvsi_close_protocol(struct hvsi_struct *hp)
685{
686 struct hvsi_control packet __ALIGNED__;
687
688 packet.hdr.type = VS_CONTROL_PACKET_HEADER;
689 packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno));
690 packet.hdr.len = 6;
691 packet.verb = cpu_to_be16(VSV_CLOSE_PROTOCOL);
692
693 pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
694 dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
695
696 hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
697}
698
699static int hvsi_open(struct tty_struct *tty, struct file *filp)
700{
701 struct hvsi_struct *hp;
702 unsigned long flags;
703 int ret;
704
705 pr_debug("%s\n", __func__);
706
707 hp = &hvsi_ports[tty->index];
708
709 tty->driver_data = hp;
710
711 mb();
712 if (hp->state == HVSI_FSP_DIED)
713 return -EIO;
714
715 tty_port_tty_set(&hp->port, tty);
716 spin_lock_irqsave(&hp->lock, flags);
717 hp->port.count++;
718 atomic_set(&hp->seqno, 0);
719 h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
720 spin_unlock_irqrestore(&hp->lock, flags);
721
722 if (is_console(hp))
723 return 0; /* this has already been handshaked as the console */
724
725 ret = hvsi_handshake(hp);
726 if (ret < 0) {
727 printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
728 return ret;
729 }
730
731 ret = hvsi_get_mctrl(hp);
732 if (ret < 0) {
733 printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name);
734 return ret;
735 }
736
737 ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
738 if (ret < 0) {
739 printk(KERN_ERR "%s: couldn't set DTR\n", tty->name);
740 return ret;
741 }
742
743 return 0;
744}
745
746/* wait for hvsi_write_worker to empty hp->outbuf */
747static void hvsi_flush_output(struct hvsi_struct *hp)
748{
749 wait_event_timeout(hp->emptyq, (hp->n_outbuf <= 0), HVSI_TIMEOUT);
750
751 /* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */
752 cancel_delayed_work_sync(&hp->writer);
753 flush_work(&hp->handshaker);
754
755 /*
756 * it's also possible that our timeout expired and hvsi_write_worker
757 * didn't manage to push outbuf. poof.
758 */
759 hp->n_outbuf = 0;
760}
761
762static void hvsi_close(struct tty_struct *tty, struct file *filp)
763{
764 struct hvsi_struct *hp = tty->driver_data;
765 unsigned long flags;
766
767 pr_debug("%s\n", __func__);
768
769 if (tty_hung_up_p(filp))
770 return;
771
772 spin_lock_irqsave(&hp->lock, flags);
773
774 if (--hp->port.count == 0) {
775 tty_port_tty_set(&hp->port, NULL);
776 hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
777
778 /* only close down connection if it is not the console */
779 if (!is_console(hp)) {
780 h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */
781 __set_state(hp, HVSI_CLOSED);
782 /*
783 * any data delivered to the tty layer after this will be
784 * discarded (except for XON/XOFF)
785 */
786 tty->closing = 1;
787
788 spin_unlock_irqrestore(&hp->lock, flags);
789
790 /* let any existing irq handlers finish. no more will start. */
791 synchronize_irq(hp->virq);
792
793 /* hvsi_write_worker will re-schedule until outbuf is empty. */
794 hvsi_flush_output(hp);
795
796 /* tell FSP to stop sending data */
797 hvsi_close_protocol(hp);
798
799 /*
800 * drain anything FSP is still in the middle of sending, and let
801 * hvsi_handshake drain the rest on the next open.
802 */
803 hvsi_drain_input(hp);
804
805 spin_lock_irqsave(&hp->lock, flags);
806 }
807 } else if (hp->port.count < 0)
808 printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n",
809 hp - hvsi_ports, hp->port.count);
810
811 spin_unlock_irqrestore(&hp->lock, flags);
812}
813
814static void hvsi_hangup(struct tty_struct *tty)
815{
816 struct hvsi_struct *hp = tty->driver_data;
817 unsigned long flags;
818
819 pr_debug("%s\n", __func__);
820
821 tty_port_tty_set(&hp->port, NULL);
822
823 spin_lock_irqsave(&hp->lock, flags);
824 hp->port.count = 0;
825 hp->n_outbuf = 0;
826 spin_unlock_irqrestore(&hp->lock, flags);
827}
828
829/* called with hp->lock held */
830static void hvsi_push(struct hvsi_struct *hp)
831{
832 int n;
833
834 if (hp->n_outbuf <= 0)
835 return;
836
837 n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf);
838 if (n > 0) {
839 /* success */
840 pr_debug("%s: wrote %i chars\n", __func__, n);
841 hp->n_outbuf = 0;
842 } else if (n == -EIO) {
843 __set_state(hp, HVSI_FSP_DIED);
844 printk(KERN_ERR "hvsi%i: service processor died\n", hp->index);
845 }
846}
847
848/* hvsi_write_worker will keep rescheduling itself until outbuf is empty */
849static void hvsi_write_worker(struct work_struct *work)
850{
851 struct hvsi_struct *hp =
852 container_of(work, struct hvsi_struct, writer.work);
853 unsigned long flags;
854#ifdef DEBUG
855 static long start_j = 0;
856
857 if (start_j == 0)
858 start_j = jiffies;
859#endif /* DEBUG */
860
861 spin_lock_irqsave(&hp->lock, flags);
862
863 pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
864
865 if (!is_open(hp)) {
866 /*
867 * We could have a non-open connection if the service processor died
868 * while we were busily scheduling ourselves. In that case, it could
869 * be minutes before the service processor comes back, so only try
870 * again once a second.
871 */
872 schedule_delayed_work(&hp->writer, HZ);
873 goto out;
874 }
875
876 hvsi_push(hp);
877 if (hp->n_outbuf > 0)
878 schedule_delayed_work(&hp->writer, 10);
879 else {
880#ifdef DEBUG
881 pr_debug("%s: outbuf emptied after %li jiffies\n", __func__,
882 jiffies - start_j);
883 start_j = 0;
884#endif /* DEBUG */
885 wake_up_all(&hp->emptyq);
886 tty_port_tty_wakeup(&hp->port);
887 }
888
889out:
890 spin_unlock_irqrestore(&hp->lock, flags);
891}
892
893static unsigned int hvsi_write_room(struct tty_struct *tty)
894{
895 struct hvsi_struct *hp = tty->driver_data;
896
897 return N_OUTBUF - hp->n_outbuf;
898}
899
900static unsigned int hvsi_chars_in_buffer(struct tty_struct *tty)
901{
902 struct hvsi_struct *hp = tty->driver_data;
903
904 return hp->n_outbuf;
905}
906
907static ssize_t hvsi_write(struct tty_struct *tty, const u8 *source,
908 size_t count)
909{
910 struct hvsi_struct *hp = tty->driver_data;
911 unsigned long flags;
912 size_t total = 0;
913 size_t origcount = count;
914
915 spin_lock_irqsave(&hp->lock, flags);
916
917 pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
918
919 if (!is_open(hp)) {
920 /* we're either closing or not yet open; don't accept data */
921 pr_debug("%s: not open\n", __func__);
922 goto out;
923 }
924
925 /*
926 * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf
927 * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls
928 * will see there is no room in outbuf and return.
929 */
930 while ((count > 0) && (hvsi_write_room(tty) > 0)) {
931 size_t chunksize = min_t(size_t, count, hvsi_write_room(tty));
932
933 BUG_ON(hp->n_outbuf < 0);
934 memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
935 hp->n_outbuf += chunksize;
936
937 total += chunksize;
938 source += chunksize;
939 count -= chunksize;
940 hvsi_push(hp);
941 }
942
943 if (hp->n_outbuf > 0) {
944 /*
945 * we weren't able to write it all to the hypervisor.
946 * schedule another push attempt.
947 */
948 schedule_delayed_work(&hp->writer, 10);
949 }
950
951out:
952 spin_unlock_irqrestore(&hp->lock, flags);
953
954 if (total != origcount)
955 pr_debug("%s: wanted %zu, only wrote %zu\n", __func__,
956 origcount, total);
957
958 return total;
959}
960
961/*
962 * I have never seen throttle or unthrottle called, so this little throttle
963 * buffering scheme may or may not work.
964 */
965static void hvsi_throttle(struct tty_struct *tty)
966{
967 struct hvsi_struct *hp = tty->driver_data;
968
969 pr_debug("%s\n", __func__);
970
971 h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE);
972}
973
974static void hvsi_unthrottle(struct tty_struct *tty)
975{
976 struct hvsi_struct *hp = tty->driver_data;
977 unsigned long flags;
978
979 pr_debug("%s\n", __func__);
980
981 spin_lock_irqsave(&hp->lock, flags);
982 if (hp->n_throttle) {
983 hvsi_send_overflow(hp);
984 tty_flip_buffer_push(&hp->port);
985 }
986 spin_unlock_irqrestore(&hp->lock, flags);
987
988
989 h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
990}
991
992static int hvsi_tiocmget(struct tty_struct *tty)
993{
994 struct hvsi_struct *hp = tty->driver_data;
995
996 hvsi_get_mctrl(hp);
997 return hp->mctrl;
998}
999
1000static int hvsi_tiocmset(struct tty_struct *tty,
1001 unsigned int set, unsigned int clear)
1002{
1003 struct hvsi_struct *hp = tty->driver_data;
1004 unsigned long flags;
1005 uint16_t new_mctrl;
1006
1007 /* we can only alter DTR */
1008 clear &= TIOCM_DTR;
1009 set &= TIOCM_DTR;
1010
1011 spin_lock_irqsave(&hp->lock, flags);
1012
1013 new_mctrl = (hp->mctrl & ~clear) | set;
1014
1015 if (hp->mctrl != new_mctrl) {
1016 hvsi_set_mctrl(hp, new_mctrl);
1017 hp->mctrl = new_mctrl;
1018 }
1019 spin_unlock_irqrestore(&hp->lock, flags);
1020
1021 return 0;
1022}
1023
1024
1025static const struct tty_operations hvsi_ops = {
1026 .open = hvsi_open,
1027 .close = hvsi_close,
1028 .write = hvsi_write,
1029 .hangup = hvsi_hangup,
1030 .write_room = hvsi_write_room,
1031 .chars_in_buffer = hvsi_chars_in_buffer,
1032 .throttle = hvsi_throttle,
1033 .unthrottle = hvsi_unthrottle,
1034 .tiocmget = hvsi_tiocmget,
1035 .tiocmset = hvsi_tiocmset,
1036};
1037
1038static int __init hvsi_init(void)
1039{
1040 struct tty_driver *driver;
1041 int i, ret;
1042
1043 driver = tty_alloc_driver(hvsi_count, TTY_DRIVER_REAL_RAW);
1044 if (IS_ERR(driver))
1045 return PTR_ERR(driver);
1046
1047 driver->driver_name = "hvsi";
1048 driver->name = "hvsi";
1049 driver->major = HVSI_MAJOR;
1050 driver->minor_start = HVSI_MINOR;
1051 driver->type = TTY_DRIVER_TYPE_SYSTEM;
1052 driver->init_termios = tty_std_termios;
1053 driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
1054 driver->init_termios.c_ispeed = 9600;
1055 driver->init_termios.c_ospeed = 9600;
1056 tty_set_operations(driver, &hvsi_ops);
1057
1058 for (i=0; i < hvsi_count; i++) {
1059 struct hvsi_struct *hp = &hvsi_ports[i];
1060 int ret = 1;
1061
1062 tty_port_link_device(&hp->port, driver, i);
1063
1064 ret = request_irq(hp->virq, hvsi_interrupt, 0, "hvsi", hp);
1065 if (ret)
1066 printk(KERN_ERR "HVSI: couldn't reserve irq 0x%x (error %i)\n",
1067 hp->virq, ret);
1068 }
1069 hvsi_wait = wait_for_state; /* irqs active now */
1070
1071 ret = tty_register_driver(driver);
1072 if (ret) {
1073 pr_err("Couldn't register hvsi console driver\n");
1074 goto err_free_irq;
1075 }
1076
1077 hvsi_driver = driver;
1078
1079 printk(KERN_DEBUG "HVSI: registered %i devices\n", hvsi_count);
1080
1081 return 0;
1082err_free_irq:
1083 hvsi_wait = poll_for_state;
1084 for (i = 0; i < hvsi_count; i++) {
1085 struct hvsi_struct *hp = &hvsi_ports[i];
1086
1087 free_irq(hp->virq, hp);
1088 }
1089 tty_driver_kref_put(driver);
1090
1091 return ret;
1092}
1093device_initcall(hvsi_init);
1094
1095/***** console (not tty) code: *****/
1096
1097static void hvsi_console_print(struct console *console, const char *buf,
1098 unsigned int count)
1099{
1100 struct hvsi_struct *hp = &hvsi_ports[console->index];
1101 char c[HVSI_MAX_OUTGOING_DATA] __ALIGNED__;
1102 unsigned int i = 0, n = 0;
1103 int ret, donecr = 0;
1104
1105 mb();
1106 if (!is_open(hp))
1107 return;
1108
1109 /*
1110 * ugh, we have to translate LF -> CRLF ourselves, in place.
1111 * copied from hvc_console.c:
1112 */
1113 while (count > 0 || i > 0) {
1114 if (count > 0 && i < sizeof(c)) {
1115 if (buf[n] == '\n' && !donecr) {
1116 c[i++] = '\r';
1117 donecr = 1;
1118 } else {
1119 c[i++] = buf[n++];
1120 donecr = 0;
1121 --count;
1122 }
1123 } else {
1124 ret = hvsi_put_chars(hp, c, i);
1125 if (ret < 0)
1126 i = 0;
1127 i -= ret;
1128 }
1129 }
1130}
1131
1132static struct tty_driver *hvsi_console_device(struct console *console,
1133 int *index)
1134{
1135 *index = console->index;
1136 return hvsi_driver;
1137}
1138
1139static int __init hvsi_console_setup(struct console *console, char *options)
1140{
1141 struct hvsi_struct *hp;
1142 int ret;
1143
1144 if (console->index < 0 || console->index >= hvsi_count)
1145 return -EINVAL;
1146 hp = &hvsi_ports[console->index];
1147
1148 /* give the FSP a chance to change the baud rate when we re-open */
1149 hvsi_close_protocol(hp);
1150
1151 ret = hvsi_handshake(hp);
1152 if (ret < 0)
1153 return ret;
1154
1155 ret = hvsi_get_mctrl(hp);
1156 if (ret < 0)
1157 return ret;
1158
1159 ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
1160 if (ret < 0)
1161 return ret;
1162
1163 hp->flags |= HVSI_CONSOLE;
1164
1165 return 0;
1166}
1167
1168static struct console hvsi_console = {
1169 .name = "hvsi",
1170 .write = hvsi_console_print,
1171 .device = hvsi_console_device,
1172 .setup = hvsi_console_setup,
1173 .flags = CON_PRINTBUFFER,
1174 .index = -1,
1175};
1176
1177static int __init hvsi_console_init(void)
1178{
1179 struct device_node *vty;
1180
1181 hvsi_wait = poll_for_state; /* no irqs yet; must poll */
1182
1183 /* search device tree for vty nodes */
1184 for_each_compatible_node(vty, "serial", "hvterm-protocol") {
1185 struct hvsi_struct *hp;
1186 const __be32 *vtermno, *irq;
1187
1188 vtermno = of_get_property(vty, "reg", NULL);
1189 irq = of_get_property(vty, "interrupts", NULL);
1190 if (!vtermno || !irq)
1191 continue;
1192
1193 if (hvsi_count >= MAX_NR_HVSI_CONSOLES) {
1194 of_node_put(vty);
1195 break;
1196 }
1197
1198 hp = &hvsi_ports[hvsi_count];
1199 INIT_DELAYED_WORK(&hp->writer, hvsi_write_worker);
1200 INIT_WORK(&hp->handshaker, hvsi_handshaker);
1201 init_waitqueue_head(&hp->emptyq);
1202 init_waitqueue_head(&hp->stateq);
1203 spin_lock_init(&hp->lock);
1204 tty_port_init(&hp->port);
1205 hp->index = hvsi_count;
1206 hp->inbuf_end = hp->inbuf;
1207 hp->state = HVSI_CLOSED;
1208 hp->vtermno = be32_to_cpup(vtermno);
1209 hp->virq = irq_create_mapping(NULL, be32_to_cpup(irq));
1210 if (hp->virq == 0) {
1211 printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
1212 __func__, be32_to_cpup(irq));
1213 tty_port_destroy(&hp->port);
1214 continue;
1215 }
1216
1217 hvsi_count++;
1218 }
1219
1220 if (hvsi_count)
1221 register_console(&hvsi_console);
1222 return 0;
1223}
1224console_initcall(hvsi_console_init);
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
71struct hvsi_struct {
72 struct delayed_work 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 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};
97static struct hvsi_struct hvsi_ports[MAX_NR_HVSI_CONSOLES];
98
99static struct tty_driver *hvsi_driver;
100static int hvsi_count;
101static int (*hvsi_wait)(struct hvsi_struct *hp, int state);
102
103enum 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
112
113static inline int is_console(struct hvsi_struct *hp)
114{
115 return hp->flags & HVSI_CONSOLE;
116}
117
118static inline int is_open(struct hvsi_struct *hp)
119{
120 /* if we're waiting for an mctrl then we're already open */
121 return (hp->state == HVSI_OPEN)
122 || (hp->state == HVSI_WAIT_FOR_MCTRL_RESPONSE);
123}
124
125static inline void print_state(struct hvsi_struct *hp)
126{
127#ifdef DEBUG
128 static const char *state_names[] = {
129 "HVSI_CLOSED",
130 "HVSI_WAIT_FOR_VER_RESPONSE",
131 "HVSI_WAIT_FOR_VER_QUERY",
132 "HVSI_OPEN",
133 "HVSI_WAIT_FOR_MCTRL_RESPONSE",
134 "HVSI_FSP_DIED",
135 };
136 const char *name = (hp->state < ARRAY_SIZE(state_names))
137 ? state_names[hp->state] : "UNKNOWN";
138
139 pr_debug("hvsi%i: state = %s\n", hp->index, name);
140#endif /* DEBUG */
141}
142
143static inline void __set_state(struct hvsi_struct *hp, int state)
144{
145 hp->state = state;
146 print_state(hp);
147 wake_up_all(&hp->stateq);
148}
149
150static inline void set_state(struct hvsi_struct *hp, int state)
151{
152 unsigned long flags;
153
154 spin_lock_irqsave(&hp->lock, flags);
155 __set_state(hp, state);
156 spin_unlock_irqrestore(&hp->lock, flags);
157}
158
159static inline int len_packet(const uint8_t *packet)
160{
161 return (int)((struct hvsi_header *)packet)->len;
162}
163
164static inline int is_header(const uint8_t *packet)
165{
166 struct hvsi_header *header = (struct hvsi_header *)packet;
167 return header->type >= VS_QUERY_RESPONSE_PACKET_HEADER;
168}
169
170static inline int got_packet(const struct hvsi_struct *hp, uint8_t *packet)
171{
172 if (hp->inbuf_end < packet + sizeof(struct hvsi_header))
173 return 0; /* don't even have the packet header */
174
175 if (hp->inbuf_end < (packet + len_packet(packet)))
176 return 0; /* don't have the rest of the packet */
177
178 return 1;
179}
180
181/* shift remaining bytes in packetbuf down */
182static void compact_inbuf(struct hvsi_struct *hp, uint8_t *read_to)
183{
184 int remaining = (int)(hp->inbuf_end - read_to);
185
186 pr_debug("%s: %i chars remain\n", __func__, remaining);
187
188 if (read_to != hp->inbuf)
189 memmove(hp->inbuf, read_to, remaining);
190
191 hp->inbuf_end = hp->inbuf + remaining;
192}
193
194#ifdef DEBUG
195#define dbg_dump_packet(packet) dump_packet(packet)
196#define dbg_dump_hex(data, len) dump_hex(data, len)
197#else
198#define dbg_dump_packet(packet) do { } while (0)
199#define dbg_dump_hex(data, len) do { } while (0)
200#endif
201
202static void dump_hex(const uint8_t *data, int len)
203{
204 int i;
205
206 printk(" ");
207 for (i=0; i < len; i++)
208 printk("%.2x", data[i]);
209
210 printk("\n ");
211 for (i=0; i < len; i++) {
212 if (isprint(data[i]))
213 printk("%c", data[i]);
214 else
215 printk(".");
216 }
217 printk("\n");
218}
219
220static void dump_packet(uint8_t *packet)
221{
222 struct hvsi_header *header = (struct hvsi_header *)packet;
223
224 printk("type 0x%x, len %i, seqno %i:\n", header->type, header->len,
225 header->seqno);
226
227 dump_hex(packet, header->len);
228}
229
230static int hvsi_read(struct hvsi_struct *hp, char *buf, int count)
231{
232 unsigned long got;
233
234 got = hvc_get_chars(hp->vtermno, buf, count);
235
236 return got;
237}
238
239static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet,
240 struct tty_struct **to_hangup, struct hvsi_struct **to_handshake)
241{
242 struct hvsi_control *header = (struct hvsi_control *)packet;
243
244 switch (header->verb) {
245 case VSV_MODEM_CTL_UPDATE:
246 if ((header->word & HVSI_TSCD) == 0) {
247 /* CD went away; no more connection */
248 pr_debug("hvsi%i: CD dropped\n", hp->index);
249 hp->mctrl &= TIOCM_CD;
250 /* If userland hasn't done an open(2) yet, hp->tty is NULL. */
251 if (hp->tty && !(hp->tty->flags & CLOCAL))
252 *to_hangup = hp->tty;
253 }
254 break;
255 case VSV_CLOSE_PROTOCOL:
256 pr_debug("hvsi%i: service processor came back\n", hp->index);
257 if (hp->state != HVSI_CLOSED) {
258 *to_handshake = hp;
259 }
260 break;
261 default:
262 printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ",
263 hp->index);
264 dump_packet(packet);
265 break;
266 }
267}
268
269static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet)
270{
271 struct hvsi_query_response *resp = (struct hvsi_query_response *)packet;
272
273 switch (hp->state) {
274 case HVSI_WAIT_FOR_VER_RESPONSE:
275 __set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
276 break;
277 case HVSI_WAIT_FOR_MCTRL_RESPONSE:
278 hp->mctrl = 0;
279 if (resp->u.mctrl_word & HVSI_TSDTR)
280 hp->mctrl |= TIOCM_DTR;
281 if (resp->u.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 */
293static 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 = atomic_inc_return(&hp->seqno);
301 packet.verb = VSV_SEND_VERSION_NUMBER;
302 packet.u.version = HVSI_VERSION;
303 packet.query_seqno = 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
318static 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, 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
334static 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->tty, 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
363static struct tty_struct *hvsi_recv_data(struct hvsi_struct *hp,
364 const uint8_t *packet)
365{
366 const struct hvsi_header *header = (const struct hvsi_header *)packet;
367 const uint8_t *data = packet + sizeof(struct hvsi_header);
368 int datalen = header->len - sizeof(struct hvsi_header);
369 int overflow = datalen - TTY_THRESHOLD_THROTTLE;
370
371 pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data);
372
373 if (datalen == 0)
374 return NULL;
375
376 if (overflow > 0) {
377 pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __func__);
378 datalen = TTY_THRESHOLD_THROTTLE;
379 }
380
381 hvsi_insert_chars(hp, data, datalen);
382
383 if (overflow > 0) {
384 /*
385 * we still have more data to deliver, so we need to save off the
386 * overflow and send it later
387 */
388 pr_debug("%s: deferring overflow\n", __func__);
389 memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow);
390 hp->n_throttle = overflow;
391 }
392
393 return hp->tty;
394}
395
396/*
397 * Returns true/false indicating data successfully read from hypervisor.
398 * Used both to get packets for tty connections and to advance the state
399 * machine during console handshaking (in which case tty = NULL and we ignore
400 * incoming data).
401 */
402static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip,
403 struct tty_struct **hangup, struct hvsi_struct **handshake)
404{
405 uint8_t *packet = hp->inbuf;
406 int chunklen;
407
408 *flip = NULL;
409 *hangup = NULL;
410 *handshake = NULL;
411
412 chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
413 if (chunklen == 0) {
414 pr_debug("%s: 0-length read\n", __func__);
415 return 0;
416 }
417
418 pr_debug("%s: got %i bytes\n", __func__, chunklen);
419 dbg_dump_hex(hp->inbuf_end, chunklen);
420
421 hp->inbuf_end += chunklen;
422
423 /* handle all completed packets */
424 while ((packet < hp->inbuf_end) && got_packet(hp, packet)) {
425 struct hvsi_header *header = (struct hvsi_header *)packet;
426
427 if (!is_header(packet)) {
428 printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index);
429 /* skip bytes until we find a header or run out of data */
430 while ((packet < hp->inbuf_end) && (!is_header(packet)))
431 packet++;
432 continue;
433 }
434
435 pr_debug("%s: handling %i-byte packet\n", __func__,
436 len_packet(packet));
437 dbg_dump_packet(packet);
438
439 switch (header->type) {
440 case VS_DATA_PACKET_HEADER:
441 if (!is_open(hp))
442 break;
443 if (hp->tty == NULL)
444 break; /* no tty buffer to put data in */
445 *flip = hvsi_recv_data(hp, packet);
446 break;
447 case VS_CONTROL_PACKET_HEADER:
448 hvsi_recv_control(hp, packet, hangup, handshake);
449 break;
450 case VS_QUERY_RESPONSE_PACKET_HEADER:
451 hvsi_recv_response(hp, packet);
452 break;
453 case VS_QUERY_PACKET_HEADER:
454 hvsi_recv_query(hp, packet);
455 break;
456 default:
457 printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
458 hp->index, header->type);
459 dump_packet(packet);
460 break;
461 }
462
463 packet += len_packet(packet);
464
465 if (*hangup || *handshake) {
466 pr_debug("%s: hangup or handshake\n", __func__);
467 /*
468 * we need to send the hangup now before receiving any more data.
469 * If we get "data, hangup, data", we can't deliver the second
470 * data before the hangup.
471 */
472 break;
473 }
474 }
475
476 compact_inbuf(hp, packet);
477
478 return 1;
479}
480
481static void hvsi_send_overflow(struct hvsi_struct *hp)
482{
483 pr_debug("%s: delivering %i bytes overflow\n", __func__,
484 hp->n_throttle);
485
486 hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);
487 hp->n_throttle = 0;
488}
489
490/*
491 * must get all pending data because we only get an irq on empty->non-empty
492 * transition
493 */
494static irqreturn_t hvsi_interrupt(int irq, void *arg)
495{
496 struct hvsi_struct *hp = (struct hvsi_struct *)arg;
497 struct tty_struct *flip;
498 struct tty_struct *hangup;
499 struct hvsi_struct *handshake;
500 unsigned long flags;
501 int again = 1;
502
503 pr_debug("%s\n", __func__);
504
505 while (again) {
506 spin_lock_irqsave(&hp->lock, flags);
507 again = hvsi_load_chunk(hp, &flip, &hangup, &handshake);
508 spin_unlock_irqrestore(&hp->lock, flags);
509
510 /*
511 * we have to call tty_flip_buffer_push() and tty_hangup() outside our
512 * spinlock. But we also have to keep going until we've read all the
513 * available data.
514 */
515
516 if (flip) {
517 /* there was data put in the tty flip buffer */
518 tty_flip_buffer_push(flip);
519 flip = NULL;
520 }
521
522 if (hangup) {
523 tty_hangup(hangup);
524 }
525
526 if (handshake) {
527 pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
528 schedule_work(&handshake->handshaker);
529 }
530 }
531
532 spin_lock_irqsave(&hp->lock, flags);
533 if (hp->tty && hp->n_throttle
534 && (!test_bit(TTY_THROTTLED, &hp->tty->flags))) {
535 /* we weren't hung up and we weren't throttled, so we can deliver the
536 * rest now */
537 flip = hp->tty;
538 hvsi_send_overflow(hp);
539 }
540 spin_unlock_irqrestore(&hp->lock, flags);
541
542 if (flip) {
543 tty_flip_buffer_push(flip);
544 }
545
546 return IRQ_HANDLED;
547}
548
549/* for boot console, before the irq handler is running */
550static int __init poll_for_state(struct hvsi_struct *hp, int state)
551{
552 unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
553
554 for (;;) {
555 hvsi_interrupt(hp->virq, (void *)hp); /* get pending data */
556
557 if (hp->state == state)
558 return 0;
559
560 mdelay(5);
561 if (time_after(jiffies, end_jiffies))
562 return -EIO;
563 }
564}
565
566/* wait for irq handler to change our state */
567static int wait_for_state(struct hvsi_struct *hp, int state)
568{
569 int ret = 0;
570
571 if (!wait_event_timeout(hp->stateq, (hp->state == state), HVSI_TIMEOUT))
572 ret = -EIO;
573
574 return ret;
575}
576
577static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
578{
579 struct hvsi_query packet __ALIGNED__;
580 int wrote;
581
582 packet.hdr.type = VS_QUERY_PACKET_HEADER;
583 packet.hdr.len = sizeof(struct hvsi_query);
584 packet.hdr.seqno = atomic_inc_return(&hp->seqno);
585 packet.verb = verb;
586
587 pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
588 dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
589
590 wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
591 if (wrote != packet.hdr.len) {
592 printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
593 wrote);
594 return -EIO;
595 }
596
597 return 0;
598}
599
600static int hvsi_get_mctrl(struct hvsi_struct *hp)
601{
602 int ret;
603
604 set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
605 hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
606
607 ret = hvsi_wait(hp, HVSI_OPEN);
608 if (ret < 0) {
609 printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
610 set_state(hp, HVSI_OPEN);
611 return ret;
612 }
613
614 pr_debug("%s: mctrl 0x%x\n", __func__, hp->mctrl);
615
616 return 0;
617}
618
619/* note that we can only set DTR */
620static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
621{
622 struct hvsi_control packet __ALIGNED__;
623 int wrote;
624
625 packet.hdr.type = VS_CONTROL_PACKET_HEADER,
626 packet.hdr.seqno = atomic_inc_return(&hp->seqno);
627 packet.hdr.len = sizeof(struct hvsi_control);
628 packet.verb = VSV_SET_MODEM_CTL;
629 packet.mask = HVSI_TSDTR;
630
631 if (mctrl & TIOCM_DTR)
632 packet.word = HVSI_TSDTR;
633
634 pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
635 dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
636
637 wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
638 if (wrote != packet.hdr.len) {
639 printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
640 return -EIO;
641 }
642
643 return 0;
644}
645
646static void hvsi_drain_input(struct hvsi_struct *hp)
647{
648 uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
649 unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
650
651 while (time_before(end_jiffies, jiffies))
652 if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
653 break;
654}
655
656static int hvsi_handshake(struct hvsi_struct *hp)
657{
658 int ret;
659
660 /*
661 * We could have a CLOSE or other data waiting for us before we even try
662 * to open; try to throw it all away so we don't get confused. (CLOSE
663 * is the first message sent up the pipe when the FSP comes online. We
664 * need to distinguish between "it came up a while ago and we're the first
665 * user" and "it was just reset before it saw our handshake packet".)
666 */
667 hvsi_drain_input(hp);
668
669 set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
670 ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
671 if (ret < 0) {
672 printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
673 return ret;
674 }
675
676 ret = hvsi_wait(hp, HVSI_OPEN);
677 if (ret < 0)
678 return ret;
679
680 return 0;
681}
682
683static void hvsi_handshaker(struct work_struct *work)
684{
685 struct hvsi_struct *hp =
686 container_of(work, struct hvsi_struct, handshaker);
687
688 if (hvsi_handshake(hp) >= 0)
689 return;
690
691 printk(KERN_ERR "hvsi%i: re-handshaking failed\n", hp->index);
692 if (is_console(hp)) {
693 /*
694 * ttys will re-attempt the handshake via hvsi_open, but
695 * the console will not.
696 */
697 printk(KERN_ERR "hvsi%i: lost console!\n", hp->index);
698 }
699}
700
701static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
702{
703 struct hvsi_data packet __ALIGNED__;
704 int ret;
705
706 BUG_ON(count > HVSI_MAX_OUTGOING_DATA);
707
708 packet.hdr.type = VS_DATA_PACKET_HEADER;
709 packet.hdr.seqno = atomic_inc_return(&hp->seqno);
710 packet.hdr.len = count + sizeof(struct hvsi_header);
711 memcpy(&packet.data, buf, count);
712
713 ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
714 if (ret == packet.hdr.len) {
715 /* return the number of chars written, not the packet length */
716 return count;
717 }
718 return ret; /* return any errors */
719}
720
721static void hvsi_close_protocol(struct hvsi_struct *hp)
722{
723 struct hvsi_control packet __ALIGNED__;
724
725 packet.hdr.type = VS_CONTROL_PACKET_HEADER;
726 packet.hdr.seqno = atomic_inc_return(&hp->seqno);
727 packet.hdr.len = 6;
728 packet.verb = VSV_CLOSE_PROTOCOL;
729
730 pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
731 dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
732
733 hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
734}
735
736static int hvsi_open(struct tty_struct *tty, struct file *filp)
737{
738 struct hvsi_struct *hp;
739 unsigned long flags;
740 int line = tty->index;
741 int ret;
742
743 pr_debug("%s\n", __func__);
744
745 if (line < 0 || line >= hvsi_count)
746 return -ENODEV;
747 hp = &hvsi_ports[line];
748
749 tty->driver_data = hp;
750
751 mb();
752 if (hp->state == HVSI_FSP_DIED)
753 return -EIO;
754
755 spin_lock_irqsave(&hp->lock, flags);
756 hp->tty = tty;
757 hp->count++;
758 atomic_set(&hp->seqno, 0);
759 h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
760 spin_unlock_irqrestore(&hp->lock, flags);
761
762 if (is_console(hp))
763 return 0; /* this has already been handshaked as the console */
764
765 ret = hvsi_handshake(hp);
766 if (ret < 0) {
767 printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
768 return ret;
769 }
770
771 ret = hvsi_get_mctrl(hp);
772 if (ret < 0) {
773 printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name);
774 return ret;
775 }
776
777 ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
778 if (ret < 0) {
779 printk(KERN_ERR "%s: couldn't set DTR\n", tty->name);
780 return ret;
781 }
782
783 return 0;
784}
785
786/* wait for hvsi_write_worker to empty hp->outbuf */
787static void hvsi_flush_output(struct hvsi_struct *hp)
788{
789 wait_event_timeout(hp->emptyq, (hp->n_outbuf <= 0), HVSI_TIMEOUT);
790
791 /* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */
792 cancel_delayed_work_sync(&hp->writer);
793 flush_work_sync(&hp->handshaker);
794
795 /*
796 * it's also possible that our timeout expired and hvsi_write_worker
797 * didn't manage to push outbuf. poof.
798 */
799 hp->n_outbuf = 0;
800}
801
802static void hvsi_close(struct tty_struct *tty, struct file *filp)
803{
804 struct hvsi_struct *hp = tty->driver_data;
805 unsigned long flags;
806
807 pr_debug("%s\n", __func__);
808
809 if (tty_hung_up_p(filp))
810 return;
811
812 spin_lock_irqsave(&hp->lock, flags);
813
814 if (--hp->count == 0) {
815 hp->tty = NULL;
816 hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
817
818 /* only close down connection if it is not the console */
819 if (!is_console(hp)) {
820 h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */
821 __set_state(hp, HVSI_CLOSED);
822 /*
823 * any data delivered to the tty layer after this will be
824 * discarded (except for XON/XOFF)
825 */
826 tty->closing = 1;
827
828 spin_unlock_irqrestore(&hp->lock, flags);
829
830 /* let any existing irq handlers finish. no more will start. */
831 synchronize_irq(hp->virq);
832
833 /* hvsi_write_worker will re-schedule until outbuf is empty. */
834 hvsi_flush_output(hp);
835
836 /* tell FSP to stop sending data */
837 hvsi_close_protocol(hp);
838
839 /*
840 * drain anything FSP is still in the middle of sending, and let
841 * hvsi_handshake drain the rest on the next open.
842 */
843 hvsi_drain_input(hp);
844
845 spin_lock_irqsave(&hp->lock, flags);
846 }
847 } else if (hp->count < 0)
848 printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n",
849 hp - hvsi_ports, hp->count);
850
851 spin_unlock_irqrestore(&hp->lock, flags);
852}
853
854static void hvsi_hangup(struct tty_struct *tty)
855{
856 struct hvsi_struct *hp = tty->driver_data;
857 unsigned long flags;
858
859 pr_debug("%s\n", __func__);
860
861 spin_lock_irqsave(&hp->lock, flags);
862
863 hp->count = 0;
864 hp->n_outbuf = 0;
865 hp->tty = NULL;
866
867 spin_unlock_irqrestore(&hp->lock, flags);
868}
869
870/* called with hp->lock held */
871static void hvsi_push(struct hvsi_struct *hp)
872{
873 int n;
874
875 if (hp->n_outbuf <= 0)
876 return;
877
878 n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf);
879 if (n > 0) {
880 /* success */
881 pr_debug("%s: wrote %i chars\n", __func__, n);
882 hp->n_outbuf = 0;
883 } else if (n == -EIO) {
884 __set_state(hp, HVSI_FSP_DIED);
885 printk(KERN_ERR "hvsi%i: service processor died\n", hp->index);
886 }
887}
888
889/* hvsi_write_worker will keep rescheduling itself until outbuf is empty */
890static void hvsi_write_worker(struct work_struct *work)
891{
892 struct hvsi_struct *hp =
893 container_of(work, struct hvsi_struct, writer.work);
894 unsigned long flags;
895#ifdef DEBUG
896 static long start_j = 0;
897
898 if (start_j == 0)
899 start_j = jiffies;
900#endif /* DEBUG */
901
902 spin_lock_irqsave(&hp->lock, flags);
903
904 pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
905
906 if (!is_open(hp)) {
907 /*
908 * We could have a non-open connection if the service processor died
909 * while we were busily scheduling ourselves. In that case, it could
910 * be minutes before the service processor comes back, so only try
911 * again once a second.
912 */
913 schedule_delayed_work(&hp->writer, HZ);
914 goto out;
915 }
916
917 hvsi_push(hp);
918 if (hp->n_outbuf > 0)
919 schedule_delayed_work(&hp->writer, 10);
920 else {
921#ifdef DEBUG
922 pr_debug("%s: outbuf emptied after %li jiffies\n", __func__,
923 jiffies - start_j);
924 start_j = 0;
925#endif /* DEBUG */
926 wake_up_all(&hp->emptyq);
927 tty_wakeup(hp->tty);
928 }
929
930out:
931 spin_unlock_irqrestore(&hp->lock, flags);
932}
933
934static int hvsi_write_room(struct tty_struct *tty)
935{
936 struct hvsi_struct *hp = tty->driver_data;
937
938 return N_OUTBUF - hp->n_outbuf;
939}
940
941static int hvsi_chars_in_buffer(struct tty_struct *tty)
942{
943 struct hvsi_struct *hp = tty->driver_data;
944
945 return hp->n_outbuf;
946}
947
948static int hvsi_write(struct tty_struct *tty,
949 const unsigned char *buf, int count)
950{
951 struct hvsi_struct *hp = tty->driver_data;
952 const char *source = buf;
953 unsigned long flags;
954 int total = 0;
955 int origcount = count;
956
957 spin_lock_irqsave(&hp->lock, flags);
958
959 pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
960
961 if (!is_open(hp)) {
962 /* we're either closing or not yet open; don't accept data */
963 pr_debug("%s: not open\n", __func__);
964 goto out;
965 }
966
967 /*
968 * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf
969 * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls
970 * will see there is no room in outbuf and return.
971 */
972 while ((count > 0) && (hvsi_write_room(hp->tty) > 0)) {
973 int chunksize = min(count, hvsi_write_room(hp->tty));
974
975 BUG_ON(hp->n_outbuf < 0);
976 memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
977 hp->n_outbuf += chunksize;
978
979 total += chunksize;
980 source += chunksize;
981 count -= chunksize;
982 hvsi_push(hp);
983 }
984
985 if (hp->n_outbuf > 0) {
986 /*
987 * we weren't able to write it all to the hypervisor.
988 * schedule another push attempt.
989 */
990 schedule_delayed_work(&hp->writer, 10);
991 }
992
993out:
994 spin_unlock_irqrestore(&hp->lock, flags);
995
996 if (total != origcount)
997 pr_debug("%s: wanted %i, only wrote %i\n", __func__, origcount,
998 total);
999
1000 return total;
1001}
1002
1003/*
1004 * I have never seen throttle or unthrottle called, so this little throttle
1005 * buffering scheme may or may not work.
1006 */
1007static void hvsi_throttle(struct tty_struct *tty)
1008{
1009 struct hvsi_struct *hp = tty->driver_data;
1010
1011 pr_debug("%s\n", __func__);
1012
1013 h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE);
1014}
1015
1016static void hvsi_unthrottle(struct tty_struct *tty)
1017{
1018 struct hvsi_struct *hp = tty->driver_data;
1019 unsigned long flags;
1020 int shouldflip = 0;
1021
1022 pr_debug("%s\n", __func__);
1023
1024 spin_lock_irqsave(&hp->lock, flags);
1025 if (hp->n_throttle) {
1026 hvsi_send_overflow(hp);
1027 shouldflip = 1;
1028 }
1029 spin_unlock_irqrestore(&hp->lock, flags);
1030
1031 if (shouldflip)
1032 tty_flip_buffer_push(hp->tty);
1033
1034 h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
1035}
1036
1037static int hvsi_tiocmget(struct tty_struct *tty)
1038{
1039 struct hvsi_struct *hp = tty->driver_data;
1040
1041 hvsi_get_mctrl(hp);
1042 return hp->mctrl;
1043}
1044
1045static int hvsi_tiocmset(struct tty_struct *tty,
1046 unsigned int set, unsigned int clear)
1047{
1048 struct hvsi_struct *hp = tty->driver_data;
1049 unsigned long flags;
1050 uint16_t new_mctrl;
1051
1052 /* we can only alter DTR */
1053 clear &= TIOCM_DTR;
1054 set &= TIOCM_DTR;
1055
1056 spin_lock_irqsave(&hp->lock, flags);
1057
1058 new_mctrl = (hp->mctrl & ~clear) | set;
1059
1060 if (hp->mctrl != new_mctrl) {
1061 hvsi_set_mctrl(hp, new_mctrl);
1062 hp->mctrl = new_mctrl;
1063 }
1064 spin_unlock_irqrestore(&hp->lock, flags);
1065
1066 return 0;
1067}
1068
1069
1070static const struct tty_operations hvsi_ops = {
1071 .open = hvsi_open,
1072 .close = hvsi_close,
1073 .write = hvsi_write,
1074 .hangup = hvsi_hangup,
1075 .write_room = hvsi_write_room,
1076 .chars_in_buffer = hvsi_chars_in_buffer,
1077 .throttle = hvsi_throttle,
1078 .unthrottle = hvsi_unthrottle,
1079 .tiocmget = hvsi_tiocmget,
1080 .tiocmset = hvsi_tiocmset,
1081};
1082
1083static int __init hvsi_init(void)
1084{
1085 int i;
1086
1087 hvsi_driver = alloc_tty_driver(hvsi_count);
1088 if (!hvsi_driver)
1089 return -ENOMEM;
1090
1091 hvsi_driver->owner = THIS_MODULE;
1092 hvsi_driver->driver_name = "hvsi";
1093 hvsi_driver->name = "hvsi";
1094 hvsi_driver->major = HVSI_MAJOR;
1095 hvsi_driver->minor_start = HVSI_MINOR;
1096 hvsi_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1097 hvsi_driver->init_termios = tty_std_termios;
1098 hvsi_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
1099 hvsi_driver->init_termios.c_ispeed = 9600;
1100 hvsi_driver->init_termios.c_ospeed = 9600;
1101 hvsi_driver->flags = TTY_DRIVER_REAL_RAW;
1102 tty_set_operations(hvsi_driver, &hvsi_ops);
1103
1104 for (i=0; i < hvsi_count; i++) {
1105 struct hvsi_struct *hp = &hvsi_ports[i];
1106 int ret = 1;
1107
1108 ret = request_irq(hp->virq, hvsi_interrupt, IRQF_DISABLED, "hvsi", hp);
1109 if (ret)
1110 printk(KERN_ERR "HVSI: couldn't reserve irq 0x%x (error %i)\n",
1111 hp->virq, ret);
1112 }
1113 hvsi_wait = wait_for_state; /* irqs active now */
1114
1115 if (tty_register_driver(hvsi_driver))
1116 panic("Couldn't register hvsi console driver\n");
1117
1118 printk(KERN_DEBUG "HVSI: registered %i devices\n", hvsi_count);
1119
1120 return 0;
1121}
1122device_initcall(hvsi_init);
1123
1124/***** console (not tty) code: *****/
1125
1126static void hvsi_console_print(struct console *console, const char *buf,
1127 unsigned int count)
1128{
1129 struct hvsi_struct *hp = &hvsi_ports[console->index];
1130 char c[HVSI_MAX_OUTGOING_DATA] __ALIGNED__;
1131 unsigned int i = 0, n = 0;
1132 int ret, donecr = 0;
1133
1134 mb();
1135 if (!is_open(hp))
1136 return;
1137
1138 /*
1139 * ugh, we have to translate LF -> CRLF ourselves, in place.
1140 * copied from hvc_console.c:
1141 */
1142 while (count > 0 || i > 0) {
1143 if (count > 0 && i < sizeof(c)) {
1144 if (buf[n] == '\n' && !donecr) {
1145 c[i++] = '\r';
1146 donecr = 1;
1147 } else {
1148 c[i++] = buf[n++];
1149 donecr = 0;
1150 --count;
1151 }
1152 } else {
1153 ret = hvsi_put_chars(hp, c, i);
1154 if (ret < 0)
1155 i = 0;
1156 i -= ret;
1157 }
1158 }
1159}
1160
1161static struct tty_driver *hvsi_console_device(struct console *console,
1162 int *index)
1163{
1164 *index = console->index;
1165 return hvsi_driver;
1166}
1167
1168static int __init hvsi_console_setup(struct console *console, char *options)
1169{
1170 struct hvsi_struct *hp;
1171 int ret;
1172
1173 if (console->index < 0 || console->index >= hvsi_count)
1174 return -1;
1175 hp = &hvsi_ports[console->index];
1176
1177 /* give the FSP a chance to change the baud rate when we re-open */
1178 hvsi_close_protocol(hp);
1179
1180 ret = hvsi_handshake(hp);
1181 if (ret < 0)
1182 return ret;
1183
1184 ret = hvsi_get_mctrl(hp);
1185 if (ret < 0)
1186 return ret;
1187
1188 ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
1189 if (ret < 0)
1190 return ret;
1191
1192 hp->flags |= HVSI_CONSOLE;
1193
1194 return 0;
1195}
1196
1197static struct console hvsi_console = {
1198 .name = "hvsi",
1199 .write = hvsi_console_print,
1200 .device = hvsi_console_device,
1201 .setup = hvsi_console_setup,
1202 .flags = CON_PRINTBUFFER,
1203 .index = -1,
1204};
1205
1206static int __init hvsi_console_init(void)
1207{
1208 struct device_node *vty;
1209
1210 hvsi_wait = poll_for_state; /* no irqs yet; must poll */
1211
1212 /* search device tree for vty nodes */
1213 for (vty = of_find_compatible_node(NULL, "serial", "hvterm-protocol");
1214 vty != NULL;
1215 vty = of_find_compatible_node(vty, "serial", "hvterm-protocol")) {
1216 struct hvsi_struct *hp;
1217 const uint32_t *vtermno, *irq;
1218
1219 vtermno = of_get_property(vty, "reg", NULL);
1220 irq = of_get_property(vty, "interrupts", NULL);
1221 if (!vtermno || !irq)
1222 continue;
1223
1224 if (hvsi_count >= MAX_NR_HVSI_CONSOLES) {
1225 of_node_put(vty);
1226 break;
1227 }
1228
1229 hp = &hvsi_ports[hvsi_count];
1230 INIT_DELAYED_WORK(&hp->writer, hvsi_write_worker);
1231 INIT_WORK(&hp->handshaker, hvsi_handshaker);
1232 init_waitqueue_head(&hp->emptyq);
1233 init_waitqueue_head(&hp->stateq);
1234 spin_lock_init(&hp->lock);
1235 hp->index = hvsi_count;
1236 hp->inbuf_end = hp->inbuf;
1237 hp->state = HVSI_CLOSED;
1238 hp->vtermno = *vtermno;
1239 hp->virq = irq_create_mapping(NULL, irq[0]);
1240 if (hp->virq == NO_IRQ) {
1241 printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
1242 __func__, irq[0]);
1243 continue;
1244 }
1245
1246 hvsi_count++;
1247 }
1248
1249 if (hvsi_count)
1250 register_console(&hvsi_console);
1251 return 0;
1252}
1253console_initcall(hvsi_console_init);