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[S390] cio: Rework css driver.

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Rework the css driver methods to provide sane callbacks for
subchannels of all types.

As a bonus, this cleans up and simplyfies the machine check
handling for I/O subchannels a lot.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
This commit is contained in:
Cornelia Huck
2008-07-14 09:58:45 +02:00
committed by Heiko Carstens
parent 7e9db9eaef
commit c820de39bd
9 changed files with 382 additions and 511 deletions
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123
drivers/s390/cio/css.c
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@@ -283,7 +283,7 @@ static int css_register_subchannel(struct subchannel *sch)
return ret;
}
static int css_probe_device(struct subchannel_id schid)
int css_probe_device(struct subchannel_id schid)
{
int ret;
struct subchannel *sch;
@@ -330,112 +330,6 @@ int css_sch_is_valid(struct schib *schib)
}
EXPORT_SYMBOL_GPL(css_sch_is_valid);
static int css_get_subchannel_status(struct subchannel *sch)
{
struct schib schib;
if (stsch(sch->schid, &schib))
return CIO_GONE;
if (!css_sch_is_valid(&schib))
return CIO_GONE;
if (sch->schib.pmcw.dnv && (schib.pmcw.dev != sch->schib.pmcw.dev))
return CIO_REVALIDATE;
if (!sch->lpm)
return CIO_NO_PATH;
return CIO_OPER;
}
static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
{
int event, ret, disc;
unsigned long flags;
enum { NONE, UNREGISTER, UNREGISTER_PROBE, REPROBE } action;
spin_lock_irqsave(sch->lock, flags);
disc = device_is_disconnected(sch);
if (disc && slow) {
/* Disconnected devices are evaluated directly only.*/
spin_unlock_irqrestore(sch->lock, flags);
return 0;
}
/* No interrupt after machine check - kill pending timers. */
device_kill_pending_timer(sch);
if (!disc && !slow) {
/* Non-disconnected devices are evaluated on the slow path. */
spin_unlock_irqrestore(sch->lock, flags);
return -EAGAIN;
}
event = css_get_subchannel_status(sch);
CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n",
sch->schid.ssid, sch->schid.sch_no, event,
disc ? "disconnected" : "normal",
slow ? "slow" : "fast");
/* Analyze subchannel status. */
action = NONE;
switch (event) {
case CIO_NO_PATH:
if (disc) {
/* Check if paths have become available. */
action = REPROBE;
break;
}
/* fall through */
case CIO_GONE:
/* Prevent unwanted effects when opening lock. */
cio_disable_subchannel(sch);
device_set_disconnected(sch);
/* Ask driver what to do with device. */
action = UNREGISTER;
if (sch->driver && sch->driver->notify) {
spin_unlock_irqrestore(sch->lock, flags);
ret = sch->driver->notify(sch, event);
spin_lock_irqsave(sch->lock, flags);
if (ret)
action = NONE;
}
break;
case CIO_REVALIDATE:
/* Device will be removed, so no notify necessary. */
if (disc)
/* Reprobe because immediate unregister might block. */
action = REPROBE;
else
action = UNREGISTER_PROBE;
break;
case CIO_OPER:
if (disc)
/* Get device operational again. */
action = REPROBE;
break;
}
/* Perform action. */
ret = 0;
switch (action) {
case UNREGISTER:
case UNREGISTER_PROBE:
/* Unregister device (will use subchannel lock). */
spin_unlock_irqrestore(sch->lock, flags);
css_sch_device_unregister(sch);
spin_lock_irqsave(sch->lock, flags);
/* Reset intparm to zeroes. */
sch->schib.pmcw.intparm = 0;
cio_modify(sch);
break;
case REPROBE:
device_trigger_reprobe(sch);
break;
default:
break;
}
spin_unlock_irqrestore(sch->lock, flags);
/* Probe if necessary. */
if (action == UNREGISTER_PROBE)
ret = css_probe_device(sch->schid);
return ret;
}
static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
{
struct schib schib;
@@ -454,6 +348,21 @@ static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
return css_probe_device(schid);
}
static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
{
int ret = 0;
if (sch->driver) {
if (sch->driver->sch_event)
ret = sch->driver->sch_event(sch, slow);
else
dev_dbg(&sch->dev,
"Got subchannel machine check but "
"no sch_event handler provided.\n");
}
return ret;
}
static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
{
struct subchannel *sch;