Root/drivers/tty/hvc/hvsi.c

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

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