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linux/drivers/s390/cio/device_pgid.c
Sebastian Ott cdb912a40d [S390] cio: introduce cio_update_schib 
There is the chance that we get condition code 0 for a stsch but
the resulting schib is not vaild. In the current code there are
2 cases:
* we do a check for validity of the schib after stsch, but at this
  time we have already stored the invaild schib in the subchannel
  structure. This may lead to problems.
* we don't do a check for validity, which is not that good either.

The patch addresses both issues by introducing the stsch wrapper
cio_update_schib which performs stsch on a local schib. This schib
is only written back to the subchannel if it's valid.

side note: For some functions (chp_events) the return codes are
different now (-ENXIO vs -ENODEV) but this shouldn't do harm
since the caller doesn't check for _specific_ errors.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-25 13:39:10 +01:00

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/*
* drivers/s390/cio/device_pgid.c
*
* Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
* IBM Corporation
* Author(s): Cornelia Huck (cornelia.huck@de.ibm.com)
* Martin Schwidefsky (schwidefsky@de.ibm.com)
*
* Path Group ID functions.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <asm/ccwdev.h>
#include <asm/cio.h>
#include <asm/delay.h>
#include <asm/lowcore.h>
#include "cio.h"
#include "cio_debug.h"
#include "css.h"
#include "device.h"
#include "ioasm.h"
#include "io_sch.h"
/*
* Helper function called from interrupt context to decide whether an
* operation should be tried again.
*/
static int __ccw_device_should_retry(union scsw *scsw)
{
/* CC is only valid if start function bit is set. */
if ((scsw->cmd.fctl & SCSW_FCTL_START_FUNC) && scsw->cmd.cc == 1)
return 1;
/* No more activity. For sense and set PGID we stubbornly try again. */
if (!scsw->cmd.actl)
return 1;
return 0;
}
/*
* Start Sense Path Group ID helper function. Used in ccw_device_recog
* and ccw_device_sense_pgid.
*/
static int
__ccw_device_sense_pgid_start(struct ccw_device *cdev)
{
struct subchannel *sch;
struct ccw1 *ccw;
int ret;
int i;
sch = to_subchannel(cdev->dev.parent);
/* Return if we already checked on all paths. */
if (cdev->private->imask == 0)
return (sch->lpm == 0) ? -ENODEV : -EACCES;
i = 8 - ffs(cdev->private->imask);
/* Setup sense path group id channel program. */
ccw = cdev->private->iccws;
ccw->cmd_code = CCW_CMD_SENSE_PGID;
ccw->count = sizeof (struct pgid);
ccw->flags = CCW_FLAG_SLI;
/* Reset device status. */
memset(&cdev->private->irb, 0, sizeof(struct irb));
/* Try on every path. */
ret = -ENODEV;
while (cdev->private->imask != 0) {
/* Try every path multiple times. */
ccw->cda = (__u32) __pa (&cdev->private->pgid[i]);
if (cdev->private->iretry > 0) {
cdev->private->iretry--;
/* Reset internal retry indication. */
cdev->private->flags.intretry = 0;
ret = cio_start (sch, cdev->private->iccws,
cdev->private->imask);
/* ret is 0, -EBUSY, -EACCES or -ENODEV */
if (ret != -EACCES)
return ret;
CIO_MSG_EVENT(3, "SNID - Device %04x on Subchannel "
"0.%x.%04x, lpm %02X, became 'not "
"operational'\n",
cdev->private->dev_id.devno,
sch->schid.ssid,
sch->schid.sch_no, cdev->private->imask);
}
cdev->private->imask >>= 1;
cdev->private->iretry = 5;
i++;
}
return ret;
}
void
ccw_device_sense_pgid_start(struct ccw_device *cdev)
{
int ret;
/* Set a timeout of 60s */
ccw_device_set_timeout(cdev, 60*HZ);
cdev->private->state = DEV_STATE_SENSE_PGID;
cdev->private->imask = 0x80;
cdev->private->iretry = 5;
memset (&cdev->private->pgid, 0, sizeof (cdev->private->pgid));
ret = __ccw_device_sense_pgid_start(cdev);
if (ret && ret != -EBUSY)
ccw_device_sense_pgid_done(cdev, ret);
}
/*
* Called from interrupt context to check if a valid answer
* to Sense Path Group ID was received.
*/
static int
__ccw_device_check_sense_pgid(struct ccw_device *cdev)
{
struct subchannel *sch;
struct irb *irb;
int i;
sch = to_subchannel(cdev->dev.parent);
irb = &cdev->private->irb;
if (irb->scsw.cmd.fctl & (SCSW_FCTL_HALT_FUNC | SCSW_FCTL_CLEAR_FUNC)) {
/* Retry Sense PGID if requested. */
if (cdev->private->flags.intretry) {
cdev->private->flags.intretry = 0;
return -EAGAIN;
}
return -ETIME;
}
if (irb->esw.esw0.erw.cons &&
(irb->ecw[0]&(SNS0_CMD_REJECT|SNS0_INTERVENTION_REQ))) {
/*
* If the device doesn't support the Sense Path Group ID
* command further retries wouldn't help ...
*/
return -EOPNOTSUPP;
}
if (irb->esw.esw0.erw.cons) {
CIO_MSG_EVENT(2, "SNID - device 0.%x.%04x, unit check, "
"lpum %02X, cnt %02d, sns : "
"%02X%02X%02X%02X %02X%02X%02X%02X ...\n",
cdev->private->dev_id.ssid,
cdev->private->dev_id.devno,
irb->esw.esw0.sublog.lpum,
irb->esw.esw0.erw.scnt,
irb->ecw[0], irb->ecw[1],
irb->ecw[2], irb->ecw[3],
irb->ecw[4], irb->ecw[5],
irb->ecw[6], irb->ecw[7]);
return -EAGAIN;
}
if (irb->scsw.cmd.cc == 3) {
u8 lpm;
lpm = to_io_private(sch)->orb.cmd.lpm;
CIO_MSG_EVENT(3, "SNID - Device %04x on Subchannel 0.%x.%04x,"
" lpm %02X, became 'not operational'\n",
cdev->private->dev_id.devno, sch->schid.ssid,
sch->schid.sch_no, lpm);
return -EACCES;
}
i = 8 - ffs(cdev->private->imask);
if (cdev->private->pgid[i].inf.ps.state2 == SNID_STATE2_RESVD_ELSE) {
CIO_MSG_EVENT(2, "SNID - Device %04x on Subchannel 0.%x.%04x "
"is reserved by someone else\n",
cdev->private->dev_id.devno, sch->schid.ssid,
sch->schid.sch_no);
return -EUSERS;
}
return 0;
}
/*
* Got interrupt for Sense Path Group ID.
*/
void
ccw_device_sense_pgid_irq(struct ccw_device *cdev, enum dev_event dev_event)
{
struct subchannel *sch;
struct irb *irb;
int ret;
irb = (struct irb *) __LC_IRB;
if (irb->scsw.cmd.stctl ==
(SCSW_STCTL_STATUS_PEND | SCSW_STCTL_ALERT_STATUS)) {
if (__ccw_device_should_retry(&irb->scsw)) {
ret = __ccw_device_sense_pgid_start(cdev);
if (ret && ret != -EBUSY)
ccw_device_sense_pgid_done(cdev, ret);
}
return;
}
if (ccw_device_accumulate_and_sense(cdev, irb) != 0)
return;
sch = to_subchannel(cdev->dev.parent);
ret = __ccw_device_check_sense_pgid(cdev);
memset(&cdev->private->irb, 0, sizeof(struct irb));
switch (ret) {
/* 0, -ETIME, -EOPNOTSUPP, -EAGAIN, -EACCES or -EUSERS */
case -EOPNOTSUPP: /* Sense Path Group ID not supported */
ccw_device_sense_pgid_done(cdev, -EOPNOTSUPP);
break;
case -ETIME: /* Sense path group id stopped by timeout. */
ccw_device_sense_pgid_done(cdev, -ETIME);
break;
case -EACCES: /* channel is not operational. */
sch->lpm &= ~cdev->private->imask;
/* Fall through. */
case 0: /* Sense Path Group ID successful. */
cdev->private->imask >>= 1;
cdev->private->iretry = 5;
/* Fall through. */
case -EAGAIN: /* Try again. */
ret = __ccw_device_sense_pgid_start(cdev);
if (ret != 0 && ret != -EBUSY)
ccw_device_sense_pgid_done(cdev, ret);
break;
case -EUSERS: /* device is reserved for someone else. */
ccw_device_sense_pgid_done(cdev, -EUSERS);
break;
}
}
/*
* Path Group ID helper function.
*/
static int
__ccw_device_do_pgid(struct ccw_device *cdev, __u8 func)
{
struct subchannel *sch;
struct ccw1 *ccw;
int ret;
sch = to_subchannel(cdev->dev.parent);
/* Setup sense path group id channel program. */
cdev->private->pgid[0].inf.fc = func;
ccw = cdev->private->iccws;
if (cdev->private->flags.pgid_single)
cdev->private->pgid[0].inf.fc |= SPID_FUNC_SINGLE_PATH;
else
cdev->private->pgid[0].inf.fc |= SPID_FUNC_MULTI_PATH;
ccw->cmd_code = CCW_CMD_SET_PGID;
ccw->cda = (__u32) __pa (&cdev->private->pgid[0]);
ccw->count = sizeof (struct pgid);
ccw->flags = CCW_FLAG_SLI;
/* Reset device status. */
memset(&cdev->private->irb, 0, sizeof(struct irb));
/* Try multiple times. */
ret = -EACCES;
if (cdev->private->iretry > 0) {
cdev->private->iretry--;
/* Reset internal retry indication. */
cdev->private->flags.intretry = 0;
ret = cio_start (sch, cdev->private->iccws,
cdev->private->imask);
/* We expect an interrupt in case of success or busy
* indication. */
if ((ret == 0) || (ret == -EBUSY))
return ret;
}
/* PGID command failed on this path. */
CIO_MSG_EVENT(3, "SPID - Device %04x on Subchannel "
"0.%x.%04x, lpm %02X, became 'not operational'\n",
cdev->private->dev_id.devno, sch->schid.ssid,
sch->schid.sch_no, cdev->private->imask);
return ret;
}
/*
* Helper function to send a nop ccw down a path.
*/
static int __ccw_device_do_nop(struct ccw_device *cdev)
{
struct subchannel *sch;
struct ccw1 *ccw;
int ret;
sch = to_subchannel(cdev->dev.parent);
/* Setup nop channel program. */
ccw = cdev->private->iccws;
ccw->cmd_code = CCW_CMD_NOOP;
ccw->cda = 0;
ccw->count = 0;
ccw->flags = CCW_FLAG_SLI;
/* Reset device status. */
memset(&cdev->private->irb, 0, sizeof(struct irb));
/* Try multiple times. */
ret = -EACCES;
if (cdev->private->iretry > 0) {
cdev->private->iretry--;
/* Reset internal retry indication. */
cdev->private->flags.intretry = 0;
ret = cio_start (sch, cdev->private->iccws,
cdev->private->imask);
/* We expect an interrupt in case of success or busy
* indication. */
if ((ret == 0) || (ret == -EBUSY))
return ret;
}
/* nop command failed on this path. */
CIO_MSG_EVENT(3, "NOP - Device %04x on Subchannel "
"0.%x.%04x, lpm %02X, became 'not operational'\n",
cdev->private->dev_id.devno, sch->schid.ssid,
sch->schid.sch_no, cdev->private->imask);
return ret;
}
/*
* Called from interrupt context to check if a valid answer
* to Set Path Group ID was received.
*/
static int
__ccw_device_check_pgid(struct ccw_device *cdev)
{
struct subchannel *sch;
struct irb *irb;
sch = to_subchannel(cdev->dev.parent);
irb = &cdev->private->irb;
if (irb->scsw.cmd.fctl & (SCSW_FCTL_HALT_FUNC | SCSW_FCTL_CLEAR_FUNC)) {
/* Retry Set PGID if requested. */
if (cdev->private->flags.intretry) {
cdev->private->flags.intretry = 0;
return -EAGAIN;
}
return -ETIME;
}
if (irb->esw.esw0.erw.cons) {
if (irb->ecw[0] & SNS0_CMD_REJECT)
return -EOPNOTSUPP;
/* Hmm, whatever happened, try again. */
CIO_MSG_EVENT(2, "SPID - device 0.%x.%04x, unit check, "
"cnt %02d, "
"sns : %02X%02X%02X%02X %02X%02X%02X%02X ...\n",
cdev->private->dev_id.ssid,
cdev->private->dev_id.devno,
irb->esw.esw0.erw.scnt,
irb->ecw[0], irb->ecw[1],
irb->ecw[2], irb->ecw[3],
irb->ecw[4], irb->ecw[5],
irb->ecw[6], irb->ecw[7]);
return -EAGAIN;
}
if (irb->scsw.cmd.cc == 3) {
CIO_MSG_EVENT(3, "SPID - Device %04x on Subchannel 0.%x.%04x,"
" lpm %02X, became 'not operational'\n",
cdev->private->dev_id.devno, sch->schid.ssid,
sch->schid.sch_no, cdev->private->imask);
return -EACCES;
}
return 0;
}
/*
* Called from interrupt context to check the path status after a nop has
* been send.
*/
static int __ccw_device_check_nop(struct ccw_device *cdev)
{
struct subchannel *sch;
struct irb *irb;
sch = to_subchannel(cdev->dev.parent);
irb = &cdev->private->irb;
if (irb->scsw.cmd.fctl & (SCSW_FCTL_HALT_FUNC | SCSW_FCTL_CLEAR_FUNC)) {
/* Retry NOP if requested. */
if (cdev->private->flags.intretry) {
cdev->private->flags.intretry = 0;
return -EAGAIN;
}
return -ETIME;
}
if (irb->scsw.cmd.cc == 3) {
CIO_MSG_EVENT(3, "NOP - Device %04x on Subchannel 0.%x.%04x,"
" lpm %02X, became 'not operational'\n",
cdev->private->dev_id.devno, sch->schid.ssid,
sch->schid.sch_no, cdev->private->imask);
return -EACCES;
}
return 0;
}
static void
__ccw_device_verify_start(struct ccw_device *cdev)
{
struct subchannel *sch;
__u8 func;
int ret;
sch = to_subchannel(cdev->dev.parent);
/* Repeat for all paths. */
for (; cdev->private->imask; cdev->private->imask >>= 1,
cdev->private->iretry = 5) {
if ((cdev->private->imask & sch->schib.pmcw.pam) == 0)
/* Path not available, try next. */
continue;
if (cdev->private->options.pgroup) {
if (sch->opm & cdev->private->imask)
func = SPID_FUNC_ESTABLISH;
else
func = SPID_FUNC_RESIGN;
ret = __ccw_device_do_pgid(cdev, func);
} else
ret = __ccw_device_do_nop(cdev);
/* We expect an interrupt in case of success or busy
* indication. */
if (ret == 0 || ret == -EBUSY)
return;
/* Permanent path failure, try next. */
}
/* Done with all paths. */
ccw_device_verify_done(cdev, (sch->vpm != 0) ? 0 : -ENODEV);
}
/*
* Got interrupt for Set Path Group ID.
*/
void
ccw_device_verify_irq(struct ccw_device *cdev, enum dev_event dev_event)
{
struct subchannel *sch;
struct irb *irb;
int ret;
irb = (struct irb *) __LC_IRB;
if (irb->scsw.cmd.stctl ==
(SCSW_STCTL_STATUS_PEND | SCSW_STCTL_ALERT_STATUS)) {
if (__ccw_device_should_retry(&irb->scsw))
__ccw_device_verify_start(cdev);
return;
}
if (ccw_device_accumulate_and_sense(cdev, irb) != 0)
return;
sch = to_subchannel(cdev->dev.parent);
if (cdev->private->options.pgroup)
ret = __ccw_device_check_pgid(cdev);
else
ret = __ccw_device_check_nop(cdev);
memset(&cdev->private->irb, 0, sizeof(struct irb));
switch (ret) {
/* 0, -ETIME, -EAGAIN, -EOPNOTSUPP or -EACCES */
case 0:
/* Path verification ccw finished successfully, update lpm. */
sch->vpm |= sch->opm & cdev->private->imask;
/* Go on with next path. */
cdev->private->imask >>= 1;
cdev->private->iretry = 5;
__ccw_device_verify_start(cdev);
break;
case -EOPNOTSUPP:
/*
* One of those strange devices which claim to be able
* to do multipathing but not for Set Path Group ID.
*/
if (cdev->private->flags.pgid_single)
cdev->private->options.pgroup = 0;
else
cdev->private->flags.pgid_single = 1;
/* Retry */
sch->vpm = 0;
cdev->private->imask = 0x80;
cdev->private->iretry = 5;
/* fall through. */
case -EAGAIN: /* Try again. */
__ccw_device_verify_start(cdev);
break;
case -ETIME: /* Set path group id stopped by timeout. */
ccw_device_verify_done(cdev, -ETIME);
break;
case -EACCES: /* channel is not operational. */
cdev->private->imask >>= 1;
cdev->private->iretry = 5;
__ccw_device_verify_start(cdev);
break;
}
}
void
ccw_device_verify_start(struct ccw_device *cdev)
{
struct subchannel *sch = to_subchannel(cdev->dev.parent);
cdev->private->flags.pgid_single = 0;
cdev->private->imask = 0x80;
cdev->private->iretry = 5;
/* Start with empty vpm. */
sch->vpm = 0;
/* Get current pam. */
if (cio_update_schib(sch)) {
ccw_device_verify_done(cdev, -ENODEV);
return;
}
/* After 60s path verification is considered to have failed. */
ccw_device_set_timeout(cdev, 60*HZ);
__ccw_device_verify_start(cdev);
}
static void
__ccw_device_disband_start(struct ccw_device *cdev)
{
struct subchannel *sch;
int ret;
sch = to_subchannel(cdev->dev.parent);
while (cdev->private->imask != 0) {
if (sch->lpm & cdev->private->imask) {
ret = __ccw_device_do_pgid(cdev, SPID_FUNC_DISBAND);
if (ret == 0)
return;
}
cdev->private->iretry = 5;
cdev->private->imask >>= 1;
}
ccw_device_disband_done(cdev, (sch->lpm != 0) ? 0 : -ENODEV);
}
/*
* Got interrupt for Unset Path Group ID.
*/
void
ccw_device_disband_irq(struct ccw_device *cdev, enum dev_event dev_event)
{
struct subchannel *sch;
struct irb *irb;
int ret;
irb = (struct irb *) __LC_IRB;
if (irb->scsw.cmd.stctl ==
(SCSW_STCTL_STATUS_PEND | SCSW_STCTL_ALERT_STATUS)) {
if (__ccw_device_should_retry(&irb->scsw))
__ccw_device_disband_start(cdev);
return;
}
if (ccw_device_accumulate_and_sense(cdev, irb) != 0)
return;
sch = to_subchannel(cdev->dev.parent);
ret = __ccw_device_check_pgid(cdev);
memset(&cdev->private->irb, 0, sizeof(struct irb));
switch (ret) {
/* 0, -ETIME, -EAGAIN, -EOPNOTSUPP or -EACCES */
case 0: /* disband successful. */
ccw_device_disband_done(cdev, ret);
break;
case -EOPNOTSUPP:
/*
* One of those strange devices which claim to be able
* to do multipathing but not for Unset Path Group ID.
*/
cdev->private->flags.pgid_single = 1;
/* fall through. */
case -EAGAIN: /* Try again. */
__ccw_device_disband_start(cdev);
break;
case -ETIME: /* Set path group id stopped by timeout. */
ccw_device_disband_done(cdev, -ETIME);
break;
case -EACCES: /* channel is not operational. */
cdev->private->imask >>= 1;
cdev->private->iretry = 5;
__ccw_device_disband_start(cdev);
break;
}
}
void
ccw_device_disband_start(struct ccw_device *cdev)
{
/* After 60s disbanding is considered to have failed. */
ccw_device_set_timeout(cdev, 60*HZ);
cdev->private->flags.pgid_single = 0;
cdev->private->iretry = 5;
cdev->private->imask = 0x80;
__ccw_device_disband_start(cdev);
}
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