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hvsi.c
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/*
* Copyright (C) 2004 Hollis Blanchard <hollisb@us.ibm.com>, IBM
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/* Host Virtual Serial Interface (HVSI) is a protocol between the hosted OS
* and the service processor on IBM pSeries servers. On these servers, there
* are no serial ports under the OS's control, and sometimes there is no other
* console available either. However, the service processor has two standard
* serial ports, so this over-complicated protocol allows the OS to control
* those ports by proxy.
*
* Besides data, the procotol supports the reading/writing of the serial
* port's DTR line, and the reading of the CD line. This is to allow the OS to
* control a modem attached to the service processor's serial port. Note that
* the OS cannot change the speed of the port through this protocol.
*/
#undef DEBUG
#include <linux/console.h>
#include <linux/ctype.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/major.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/sysrq.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <asm/hvcall.h>
#include <asm/hvconsole.h>
#include <asm/prom.h>
#include <asm/uaccess.h>
#include <asm/vio.h>
#include <asm/param.h>
#define HVSI_MAJOR 229
#define HVSI_MINOR 128
#define MAX_NR_HVSI_CONSOLES 4
#define HVSI_TIMEOUT (5*HZ)
#define HVSI_VERSION 1
#define HVSI_MAX_PACKET 256
#define HVSI_MAX_READ 16
#define HVSI_MAX_OUTGOING_DATA 12
#define N_OUTBUF 12
/*
* we pass data via two 8-byte registers, so we would like our char arrays
* properly aligned for those loads.
*/
#define __ALIGNED__ __attribute__((__aligned__(sizeof(long))))
struct hvsi_struct {
struct work_struct writer;
struct work_struct handshaker;
wait_queue_head_t emptyq; /* woken when outbuf is emptied */
wait_queue_head_t stateq; /* woken when HVSI state changes */
spinlock_t lock;
int index;
struct tty_struct *tty;
unsigned int count;
uint8_t throttle_buf[128];
uint8_t outbuf[N_OUTBUF]; /* to implement write_room and chars_in_buffer */
/* inbuf is for packet reassembly. leave a little room for leftovers. */
uint8_t inbuf[HVSI_MAX_PACKET + HVSI_MAX_READ];
uint8_t *inbuf_end;
int n_throttle;
int n_outbuf;
uint32_t vtermno;
uint32_t virq;
atomic_t seqno; /* HVSI packet sequence number */
uint16_t mctrl;
uint8_t state; /* HVSI protocol state */
uint8_t flags;
#ifdef CONFIG_MAGIC_SYSRQ
uint8_t sysrq;
#endif /* CONFIG_MAGIC_SYSRQ */
};
static struct hvsi_struct hvsi_ports[MAX_NR_HVSI_CONSOLES];
static struct tty_driver *hvsi_driver;
static int hvsi_count;
static int (*hvsi_wait)(struct hvsi_struct *hp, int state);
enum HVSI_PROTOCOL_STATE {
HVSI_CLOSED,
HVSI_WAIT_FOR_VER_RESPONSE,
HVSI_WAIT_FOR_VER_QUERY,
HVSI_OPEN,
HVSI_WAIT_FOR_MCTRL_RESPONSE,
HVSI_FSP_DIED,
};
#define HVSI_CONSOLE 0x1
#define VS_DATA_PACKET_HEADER 0xff
#define VS_CONTROL_PACKET_HEADER 0xfe
#define VS_QUERY_PACKET_HEADER 0xfd
#define VS_QUERY_RESPONSE_PACKET_HEADER 0xfc
/* control verbs */
#define VSV_SET_MODEM_CTL 1 /* to service processor only */
#define VSV_MODEM_CTL_UPDATE 2 /* from service processor only */
#define VSV_CLOSE_PROTOCOL 3
/* query verbs */
#define VSV_SEND_VERSION_NUMBER 1
#define VSV_SEND_MODEM_CTL_STATUS 2
/* yes, these masks are not consecutive. */
#define HVSI_TSDTR 0x01
#define HVSI_TSCD 0x20
struct hvsi_header {
uint8_t type;
uint8_t len;
uint16_t seqno;
} __attribute__((packed));
struct hvsi_data {
uint8_t type;
uint8_t len;
uint16_t seqno;
uint8_t data[HVSI_MAX_OUTGOING_DATA];
} __attribute__((packed));
struct hvsi_control {
uint8_t type;
uint8_t len;
uint16_t seqno;
uint16_t verb;
/* optional depending on verb: */
uint32_t word;
uint32_t mask;
} __attribute__((packed));
struct hvsi_query {
uint8_t type;
uint8_t len;
uint16_t seqno;
uint16_t verb;
} __attribute__((packed));
struct hvsi_query_response {
uint8_t type;
uint8_t len;
uint16_t seqno;
uint16_t verb;
uint16_t query_seqno;
union {
uint8_t version;
uint32_t mctrl_word;
} u;
} __attribute__((packed));
static inline int is_console(struct hvsi_struct *hp)
{
return hp->flags & HVSI_CONSOLE;
}
static inline int is_open(struct hvsi_struct *hp)
{
/* if we're waiting for an mctrl then we're already open */
return (hp->state == HVSI_OPEN)
|| (hp->state == HVSI_WAIT_FOR_MCTRL_RESPONSE);
}
static inline void print_state(struct hvsi_struct *hp)
{
#ifdef DEBUG
static const char *state_names[] = {
"HVSI_CLOSED",
"HVSI_WAIT_FOR_VER_RESPONSE",
"HVSI_WAIT_FOR_VER_QUERY",
"HVSI_OPEN",
"HVSI_WAIT_FOR_MCTRL_RESPONSE",
"HVSI_FSP_DIED",
};
const char *name = state_names[hp->state];
if (hp->state > (sizeof(state_names)/sizeof(char*)))
name = "UNKNOWN";
pr_debug("hvsi%i: state = %s\n", hp->index, name);
#endif /* DEBUG */
}
static inline void __set_state(struct hvsi_struct *hp, int state)
{
hp->state = state;
print_state(hp);
wake_up_all(&hp->stateq);
}
static inline void set_state(struct hvsi_struct *hp, int state)
{
unsigned long flags;
spin_lock_irqsave(&hp->lock, flags);
__set_state(hp, state);
spin_unlock_irqrestore(&hp->lock, flags);
}
static inline int len_packet(const uint8_t *packet)
{
return (int)((struct hvsi_header *)packet)->len;
}
static inline int is_header(const uint8_t *packet)
{
struct hvsi_header *header = (struct hvsi_header *)packet;
return header->type >= VS_QUERY_RESPONSE_PACKET_HEADER;
}
static inline int got_packet(const struct hvsi_struct *hp, uint8_t *packet)
{
if (hp->inbuf_end < packet + sizeof(struct hvsi_header))
return 0; /* don't even have the packet header */
if (hp->inbuf_end < (packet + len_packet(packet)))
return 0; /* don't have the rest of the packet */
return 1;
}
/* shift remaining bytes in packetbuf down */
static void compact_inbuf(struct hvsi_struct *hp, uint8_t *read_to)
{
int remaining = (int)(hp->inbuf_end - read_to);
pr_debug("%s: %i chars remain\n", __FUNCTION__, remaining);
if (read_to != hp->inbuf)
memmove(hp->inbuf, read_to, remaining);
hp->inbuf_end = hp->inbuf + remaining;
}
#ifdef DEBUG
#define dbg_dump_packet(packet) dump_packet(packet)
#define dbg_dump_hex(data, len) dump_hex(data, len)
#else
#define dbg_dump_packet(packet) do { } while (0)
#define dbg_dump_hex(data, len) do { } while (0)
#endif
static void dump_hex(const uint8_t *data, int len)
{
int i;
printk(" ");
for (i=0; i < len; i++)
printk("%.2x", data[i]);
printk("\n ");
for (i=0; i < len; i++) {
if (isprint(data[i]))
printk("%c", data[i]);
else
printk(".");
}
printk("\n");
}
static void dump_packet(uint8_t *packet)
{
struct hvsi_header *header = (struct hvsi_header *)packet;
printk("type 0x%x, len %i, seqno %i:\n", header->type, header->len,
header->seqno);
dump_hex(packet, header->len);
}
/* can't use hvc_get_chars because that strips CRs */
static int hvsi_read(struct hvsi_struct *hp, char *buf, int count)
{
unsigned long got;
if (plpar_hcall(H_GET_TERM_CHAR, hp->vtermno, 0, 0, 0, &got,
(unsigned long *)buf, (unsigned long *)buf+1) == H_Success)
return got;
return 0;
}
static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet,
struct tty_struct **to_hangup, struct hvsi_struct **to_handshake)
{
struct hvsi_control *header = (struct hvsi_control *)packet;
switch (header->verb) {
case VSV_MODEM_CTL_UPDATE:
if ((header->word & HVSI_TSCD) == 0) {
/* CD went away; no more connection */
pr_debug("hvsi%i: CD dropped\n", hp->index);
hp->mctrl &= TIOCM_CD;
if (!(hp->tty->flags & CLOCAL))
*to_hangup = hp->tty;
}
break;
case VSV_CLOSE_PROTOCOL:
pr_debug("hvsi%i: service processor came back\n", hp->index);
if (hp->state != HVSI_CLOSED) {
*to_handshake = hp;
}
break;
default:
printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ",
hp->index);
dump_packet(packet);
break;
}
}
static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet)
{
struct hvsi_query_response *resp = (struct hvsi_query_response *)packet;
switch (hp->state) {
case HVSI_WAIT_FOR_VER_RESPONSE:
__set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
break;
case HVSI_WAIT_FOR_MCTRL_RESPONSE:
hp->mctrl = 0;
if (resp->u.mctrl_word & HVSI_TSDTR)
hp->mctrl |= TIOCM_DTR;
if (resp->u.mctrl_word & HVSI_TSCD)
hp->mctrl |= TIOCM_CD;
__set_state(hp, HVSI_OPEN);
break;
default:
printk(KERN_ERR "hvsi%i: unexpected query response: ", hp->index);
dump_packet(packet);
break;
}
}
/* respond to service processor's version query */
static int hvsi_version_respond(struct hvsi_struct *hp, uint16_t query_seqno)
{
struct hvsi_query_response packet __ALIGNED__;
int wrote;
packet.type = VS_QUERY_RESPONSE_PACKET_HEADER;
packet.len = sizeof(struct hvsi_query_response);
packet.seqno = atomic_inc_return(&hp->seqno);
packet.verb = VSV_SEND_VERSION_NUMBER;
packet.u.version = HVSI_VERSION;
packet.query_seqno = query_seqno+1;
pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
dbg_dump_hex((uint8_t*)&packet, packet.len);
wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
if (wrote != packet.len) {
printk(KERN_ERR "hvsi%i: couldn't send query response!\n",
hp->index);
return -EIO;
}
return 0;
}
static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet)
{
struct hvsi_query *query = (struct hvsi_query *)packet;
switch (hp->state) {
case HVSI_WAIT_FOR_VER_QUERY:
hvsi_version_respond(hp, query->seqno);
__set_state(hp, HVSI_OPEN);
break;
default:
printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index);
dump_packet(packet);
break;
}
}
static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len)
{
int i;
for (i=0; i < len; i++) {
char c = buf[i];
#ifdef CONFIG_MAGIC_SYSRQ
if (c == '\0') {
hp->sysrq = 1;
continue;
} else if (hp->sysrq) {
handle_sysrq(c, NULL, hp->tty);
hp->sysrq = 0;
continue;
}
#endif /* CONFIG_MAGIC_SYSRQ */
tty_insert_flip_char(hp->tty, c, 0);
}
}
/*
* We could get 252 bytes of data at once here. But the tty layer only
* throttles us at TTY_THRESHOLD_THROTTLE (128) bytes, so we could overflow
* it. Accordingly we won't send more than 128 bytes at a time to the flip
* buffer, which will give the tty buffer a chance to throttle us. Should the
* value of TTY_THRESHOLD_THROTTLE change in n_tty.c, this code should be
* revisited.
*/
#define TTY_THRESHOLD_THROTTLE 128
static struct tty_struct *hvsi_recv_data(struct hvsi_struct *hp,
const uint8_t *packet)
{
const struct hvsi_header *header = (const struct hvsi_header *)packet;
const uint8_t *data = packet + sizeof(struct hvsi_header);
int datalen = header->len - sizeof(struct hvsi_header);
int overflow = datalen - TTY_THRESHOLD_THROTTLE;
pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data);
if (datalen == 0)
return NULL;
if (overflow > 0) {
pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __FUNCTION__);
datalen = TTY_THRESHOLD_THROTTLE;
}
hvsi_insert_chars(hp, data, datalen);
if (overflow > 0) {
/*
* we still have more data to deliver, so we need to save off the
* overflow and send it later
*/
pr_debug("%s: deferring overflow\n", __FUNCTION__);
memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow);
hp->n_throttle = overflow;
}
return hp->tty;
}
/*
* Returns true/false indicating data successfully read from hypervisor.
* Used both to get packets for tty connections and to advance the state
* machine during console handshaking (in which case tty = NULL and we ignore
* incoming data).
*/
static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip,
struct tty_struct **hangup, struct hvsi_struct **handshake)
{
uint8_t *packet = hp->inbuf;
int chunklen;
*flip = NULL;
*hangup = NULL;
*handshake = NULL;
chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
if (chunklen == 0) {
pr_debug("%s: 0-length read\n", __FUNCTION__);
return 0;
}
pr_debug("%s: got %i bytes\n", __FUNCTION__, chunklen);
dbg_dump_hex(hp->inbuf_end, chunklen);
hp->inbuf_end += chunklen;
/* handle all completed packets */
while ((packet < hp->inbuf_end) && got_packet(hp, packet)) {
struct hvsi_header *header = (struct hvsi_header *)packet;
if (!is_header(packet)) {
printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index);
/* skip bytes until we find a header or run out of data */
while ((packet < hp->inbuf_end) && (!is_header(packet)))
packet++;
continue;
}
pr_debug("%s: handling %i-byte packet\n", __FUNCTION__,
len_packet(packet));
dbg_dump_packet(packet);
switch (header->type) {
case VS_DATA_PACKET_HEADER:
if (!is_open(hp))
break;
if (hp->tty == NULL)
break; /* no tty buffer to put data in */
*flip = hvsi_recv_data(hp, packet);
break;
case VS_CONTROL_PACKET_HEADER:
hvsi_recv_control(hp, packet, hangup, handshake);
break;
case VS_QUERY_RESPONSE_PACKET_HEADER:
hvsi_recv_response(hp, packet);
break;
case VS_QUERY_PACKET_HEADER:
hvsi_recv_query(hp, packet);
break;
default:
printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
hp->index, header->type);
dump_packet(packet);
break;
}
packet += len_packet(packet);
if (*hangup || *handshake) {
pr_debug("%s: hangup or handshake\n", __FUNCTION__);
/*
* we need to send the hangup now before receiving any more data.
* If we get "data, hangup, data", we can't deliver the second
* data before the hangup.
*/
break;
}
}
compact_inbuf(hp, packet);
return 1;
}
static void hvsi_send_overflow(struct hvsi_struct *hp)
{
pr_debug("%s: delivering %i bytes overflow\n", __FUNCTION__,
hp->n_throttle);
hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);
hp->n_throttle = 0;
}
/*
* must get all pending data because we only get an irq on empty->non-empty
* transition
*/
static irqreturn_t hvsi_interrupt(int irq, void *arg, struct pt_regs *regs)
{
struct hvsi_struct *hp = (struct hvsi_struct *)arg;
struct tty_struct *flip;
struct tty_struct *hangup;
struct hvsi_struct *handshake;
unsigned long flags;
int again = 1;
pr_debug("%s\n", __FUNCTION__);
while (again) {
spin_lock_irqsave(&hp->lock, flags);
again = hvsi_load_chunk(hp, &flip, &hangup, &handshake);
spin_unlock_irqrestore(&hp->lock, flags);
/*
* we have to call tty_flip_buffer_push() and tty_hangup() outside our
* spinlock. But we also have to keep going until we've read all the
* available data.
*/
if (flip) {
/* there was data put in the tty flip buffer */
tty_flip_buffer_push(flip);
flip = NULL;
}
if (hangup) {
tty_hangup(hangup);
}
if (handshake) {
pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
schedule_work(&handshake->handshaker);
}
}
spin_lock_irqsave(&hp->lock, flags);
if (hp->tty && hp->n_throttle
&& (!test_bit(TTY_THROTTLED, &hp->tty->flags))) {
/* we weren't hung up and we weren't throttled, so we can deliver the
* rest now */
flip = hp->tty;
hvsi_send_overflow(hp);
}
spin_unlock_irqrestore(&hp->lock, flags);
if (flip) {
tty_flip_buffer_push(flip);
}
return IRQ_HANDLED;
}
/* for boot console, before the irq handler is running */
static int __init poll_for_state(struct hvsi_struct *hp, int state)
{
unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
for (;;) {
hvsi_interrupt(hp->virq, (void *)hp, NULL); /* get pending data */
if (hp->state == state)
return 0;
mdelay(5);
if (time_after(jiffies, end_jiffies))
return -EIO;
}
}
/* wait for irq handler to change our state */
static int wait_for_state(struct hvsi_struct *hp, int state)
{
int ret = 0;
if (!wait_event_timeout(hp->stateq, (hp->state == state), HVSI_TIMEOUT))
ret = -EIO;
return ret;
}
static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
{
struct hvsi_query packet __ALIGNED__;
int wrote;
packet.type = VS_QUERY_PACKET_HEADER;
packet.len = sizeof(struct hvsi_query);
packet.seqno = atomic_inc_return(&hp->seqno);
packet.verb = verb;
pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
dbg_dump_hex((uint8_t*)&packet, packet.len);
wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
if (wrote != packet.len) {
printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
wrote);
return -EIO;
}
return 0;
}
static int hvsi_get_mctrl(struct hvsi_struct *hp)
{
int ret;
set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
ret = hvsi_wait(hp, HVSI_OPEN);
if (ret < 0) {
printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
set_state(hp, HVSI_OPEN);
return ret;
}
pr_debug("%s: mctrl 0x%x\n", __FUNCTION__, hp->mctrl);
return 0;
}
/* note that we can only set DTR */
static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
{
struct hvsi_control packet __ALIGNED__;
int wrote;
packet.type = VS_CONTROL_PACKET_HEADER,
packet.seqno = atomic_inc_return(&hp->seqno);
packet.len = sizeof(struct hvsi_control);
packet.verb = VSV_SET_MODEM_CTL;
packet.mask = HVSI_TSDTR;
if (mctrl & TIOCM_DTR)
packet.word = HVSI_TSDTR;
pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
dbg_dump_hex((uint8_t*)&packet, packet.len);
wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
if (wrote != packet.len) {
printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
return -EIO;
}
return 0;
}
static void hvsi_drain_input(struct hvsi_struct *hp)
{
uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
while (time_before(end_jiffies, jiffies))
if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
break;
}
static int hvsi_handshake(struct hvsi_struct *hp)
{
int ret;
/*
* We could have a CLOSE or other data waiting for us before we even try
* to open; try to throw it all away so we don't get confused. (CLOSE
* is the first message sent up the pipe when the FSP comes online. We
* need to distinguish between "it came up a while ago and we're the first
* user" and "it was just reset before it saw our handshake packet".)
*/
hvsi_drain_input(hp);
set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
if (ret < 0) {
printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
return ret;
}
ret = hvsi_wait(hp, HVSI_OPEN);
if (ret < 0)
return ret;
return 0;
}
static void hvsi_handshaker(void *arg)
{
struct hvsi_struct *hp = (struct hvsi_struct *)arg;
if (hvsi_handshake(hp) >= 0)
return;
printk(KERN_ERR "hvsi%i: re-handshaking failed\n", hp->index);
if (is_console(hp)) {
/*
* ttys will re-attempt the handshake via hvsi_open, but
* the console will not.
*/
printk(KERN_ERR "hvsi%i: lost console!\n", hp->index);
}
}
static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
{
struct hvsi_data packet __ALIGNED__;
int ret;
BUG_ON(count > HVSI_MAX_OUTGOING_DATA);
packet.type = VS_DATA_PACKET_HEADER;
packet.seqno = atomic_inc_return(&hp->seqno);
packet.len = count + sizeof(struct hvsi_header);
memcpy(&packet.data, buf, count);
ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
if (ret == packet.len) {
/* return the number of chars written, not the packet length */
return count;
}
return ret; /* return any errors */
}
static void hvsi_close_protocol(struct hvsi_struct *hp)
{
struct hvsi_control packet __ALIGNED__;
packet.type = VS_CONTROL_PACKET_HEADER;
packet.seqno = atomic_inc_return(&hp->seqno);
packet.len = 6;
packet.verb = VSV_CLOSE_PROTOCOL;
pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
dbg_dump_hex((uint8_t*)&packet, packet.len);
hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
}
static int hvsi_open(struct tty_struct *tty, struct file *filp)
{
struct hvsi_struct *hp;
unsigned long flags;
int line = tty->index;
int ret;
pr_debug("%s\n", __FUNCTION__);
if (line < 0 || line >= hvsi_count)
return -ENODEV;
hp = &hvsi_ports[line];
tty->driver_data = hp;
tty->low_latency = 1; /* avoid throttle/tty_flip_buffer_push race */
mb();
if (hp->state == HVSI_FSP_DIED)
return -EIO;
spin_lock_irqsave(&hp->lock, flags);
hp->tty = tty;
hp->count++;
atomic_set(&hp->seqno, 0);
h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
spin_unlock_irqrestore(&hp->lock, flags);
if (is_console(hp))
return 0; /* this has already been handshaked as the console */
ret = hvsi_handshake(hp);
if (ret < 0) {
printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
return ret;
}
ret = hvsi_get_mctrl(hp);
if (ret < 0) {
printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name);
return ret;
}
ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
if (ret < 0) {
printk(KERN_ERR "%s: couldn't set DTR\n", tty->name);
return ret;
}
return 0;
}
/* wait for hvsi_write_worker to empty hp->outbuf */
static void hvsi_flush_output(struct hvsi_struct *hp)
{
wait_event_timeout(hp->emptyq, (hp->n_outbuf <= 0), HVSI_TIMEOUT);
/* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */
cancel_delayed_work(&hp->writer);
flush_scheduled_work();
/*
* it's also possible that our timeout expired and hvsi_write_worker
* didn't manage to push outbuf. poof.
*/
hp->n_outbuf = 0;
}
static void hvsi_close(struct tty_struct *tty, struct file *filp)
{
struct hvsi_struct *hp = tty->driver_data;
unsigned long flags;
pr_debug("%s\n", __FUNCTION__);
if (tty_hung_up_p(filp))
return;
spin_lock_irqsave(&hp->lock, flags);
if (--hp->count == 0) {
hp->tty = NULL;
hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
/* only close down connection if it is not the console */
if (!is_console(hp)) {
h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */
__set_state(hp, HVSI_CLOSED);
/*
* any data delivered to the tty layer after this will be
* discarded (except for XON/XOFF)
*/
tty->closing = 1;
spin_unlock_irqrestore(&hp->lock, flags);
/* let any existing irq handlers finish. no more will start. */
synchronize_irq(hp->virq);
/* hvsi_write_worker will re-schedule until outbuf is empty. */
hvsi_flush_output(hp);
/* tell FSP to stop sending data */
hvsi_close_protocol(hp);
/*
* drain anything FSP is still in the middle of sending, and let
* hvsi_handshake drain the rest on the next open.
*/
hvsi_drain_input(hp);
spin_lock_irqsave(&hp->lock, flags);
}
} else if (hp->count < 0)
printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n",
hp - hvsi_ports, hp->count);
spin_unlock_irqrestore(&hp->lock, flags);
}
static void hvsi_hangup(struct tty_struct *tty)
{
struct hvsi_struct *hp = tty->driver_data;
unsigned long flags;
pr_debug("%s\n", __FUNCTION__);
spin_lock_irqsave(&hp->lock, flags);
hp->count = 0;
hp->n_outbuf = 0;
hp->tty = NULL;
spin_unlock_irqrestore(&hp->lock, flags);
}
/* called with hp->lock held */
static void hvsi_push(struct hvsi_struct *hp)
{
int n;
if (hp->n_outbuf <= 0)
return;
n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf);
if (n > 0) {
/* success */
pr_debug("%s: wrote %i chars\n", __FUNCTION__, n);
hp->n_outbuf = 0;
} else if (n == -EIO) {
__set_state(hp, HVSI_FSP_DIED);
printk(KERN_ERR "hvsi%i: service processor died\n", hp->index);
}
}
/* hvsi_write_worker will keep rescheduling itself until outbuf is empty */
static void hvsi_write_worker(void *arg)
{
struct hvsi_struct *hp = (struct hvsi_struct *)arg;
unsigned long flags;
#ifdef DEBUG
static long start_j = 0;
if (start_j == 0)
start_j = jiffies;
#endif /* DEBUG */
spin_lock_irqsave(&hp->lock, flags);
pr_debug("%s: %i chars in buffer\n", __FUNCTION__, hp->n_outbuf);
if (!is_open(hp)) {
/*
* We could have a non-open connection if the service processor died
* while we were busily scheduling ourselves. In that case, it could
* be minutes before the service processor comes back, so only try
* again once a second.
*/
schedule_delayed_work(&hp->writer, HZ);
goto out;
}
hvsi_push(hp);
if (hp->n_outbuf > 0)
schedule_delayed_work(&hp->writer, 10);
else {
#ifdef DEBUG
pr_debug("%s: outbuf emptied after %li jiffies\n", __FUNCTION__,
jiffies - start_j);
start_j = 0;
#endif /* DEBUG */
wake_up_all(&hp->emptyq);
if (test_bit(TTY_DO_WRITE_WAKEUP, &hp->tty->flags)
&& hp->tty->ldisc.write_wakeup)
hp->tty->ldisc.write_wakeup(hp->tty);
wake_up_interruptible(&hp->tty->write_wait);
}
out:
spin_unlock_irqrestore(&hp->lock, flags);
}