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