[S390] cio: introduce cio_commit_config
To change the configuration of a subchannel we alter the modifiable
bits of the subchannel's schib field and issue a modify subchannel.
There can be the case that not all changes were applied -or worse-
quietly overwritten by the hardware. With the next store subchannel
we obtain the current state of the hardware but lose our target
configuration.
With this patch we introduce a subchannel_config structure which
contains the target subchannel configuration. Additionally the msch
wrapper cio_modify is replaced with cio_commit_config which
copies the desired changes to a temporary schib. msch is then
called with the temporary schib. This schib is only written back
to the subchannel if all changes were applied.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c
index 9bdb463..8f1cec4 100644
--- a/drivers/s390/cio/cio.c
+++ b/drivers/s390/cio/cio.c
@@ -330,30 +330,70 @@
}
}
-/*
- * Function: cio_modify
- * Issues a "Modify Subchannel" on the specified subchannel
- */
-int
-cio_modify (struct subchannel *sch)
-{
- int ccode, retry, ret;
- ret = 0;
+static void cio_apply_config(struct subchannel *sch, struct schib *schib)
+{
+ schib->pmcw.intparm = sch->config.intparm;
+ schib->pmcw.mbi = sch->config.mbi;
+ schib->pmcw.isc = sch->config.isc;
+ schib->pmcw.ena = sch->config.ena;
+ schib->pmcw.mme = sch->config.mme;
+ schib->pmcw.mp = sch->config.mp;
+ schib->pmcw.csense = sch->config.csense;
+ schib->pmcw.mbfc = sch->config.mbfc;
+ if (sch->config.mbfc)
+ schib->mba = sch->config.mba;
+}
+
+static int cio_check_config(struct subchannel *sch, struct schib *schib)
+{
+ return (schib->pmcw.intparm == sch->config.intparm) &&
+ (schib->pmcw.mbi == sch->config.mbi) &&
+ (schib->pmcw.isc == sch->config.isc) &&
+ (schib->pmcw.ena == sch->config.ena) &&
+ (schib->pmcw.mme == sch->config.mme) &&
+ (schib->pmcw.mp == sch->config.mp) &&
+ (schib->pmcw.csense == sch->config.csense) &&
+ (schib->pmcw.mbfc == sch->config.mbfc) &&
+ (!sch->config.mbfc || (schib->mba == sch->config.mba));
+}
+
+/*
+ * cio_commit_config - apply configuration to the subchannel
+ */
+int cio_commit_config(struct subchannel *sch)
+{
+ struct schib schib;
+ int ccode, retry, ret = 0;
+
+ if (stsch(sch->schid, &schib) || !css_sch_is_valid(&schib))
+ return -ENODEV;
+
for (retry = 0; retry < 5; retry++) {
- ccode = msch_err (sch->schid, &sch->schib);
- if (ccode < 0) /* -EIO if msch gets a program check. */
+ /* copy desired changes to local schib */
+ cio_apply_config(sch, &schib);
+ ccode = msch_err(sch->schid, &schib);
+ if (ccode < 0) /* -EIO if msch gets a program check. */
return ccode;
switch (ccode) {
case 0: /* successfull */
- return 0;
- case 1: /* status pending */
+ if (stsch(sch->schid, &schib) ||
+ !css_sch_is_valid(&schib))
+ return -ENODEV;
+ if (cio_check_config(sch, &schib)) {
+ /* commit changes from local schib */
+ memcpy(&sch->schib, &schib, sizeof(schib));
+ return 0;
+ }
+ ret = -EAGAIN;
+ break;
+ case 1: /* status pending */
return -EBUSY;
- case 2: /* busy */
- udelay (100); /* allow for recovery */
+ case 2: /* busy */
+ udelay(100); /* allow for recovery */
ret = -EBUSY;
break;
- case 3: /* not operational */
+ case 3: /* not operational */
return -ENODEV;
}
}
@@ -396,32 +436,24 @@
if (cio_update_schib(sch))
return -ENODEV;
- for (retry = 5, ret = 0; retry > 0; retry--) {
- sch->schib.pmcw.ena = 1;
- sch->schib.pmcw.isc = sch->isc;
- sch->schib.pmcw.intparm = intparm;
- ret = cio_modify(sch);
- if (ret == -ENODEV)
- break;
- if (ret == -EIO)
+ sch->config.ena = 1;
+ sch->config.isc = sch->isc;
+ sch->config.intparm = intparm;
+
+ for (retry = 0; retry < 3; retry++) {
+ ret = cio_commit_config(sch);
+ if (ret == -EIO) {
/*
- * Got a program check in cio_modify. Try without
+ * Got a program check in msch. Try without
* the concurrent sense bit the next time.
*/
- sch->schib.pmcw.csense = 0;
- if (ret == 0) {
- if (cio_update_schib(sch)) {
- ret = -ENODEV;
- break;
- }
- if (sch->schib.pmcw.ena)
- break;
- }
- if (ret == -EBUSY) {
+ sch->config.csense = 0;
+ } else if (ret == -EBUSY) {
struct irb irb;
if (tsch(sch->schid, &irb) != 0)
break;
- }
+ } else
+ break;
}
sprintf (dbf_txt, "ret:%d", ret);
CIO_TRACE_EVENT (2, dbf_txt);
@@ -436,7 +468,6 @@
int cio_disable_subchannel(struct subchannel *sch)
{
char dbf_txt[15];
- int retry;
int ret;
CIO_TRACE_EVENT (2, "dissch");
@@ -454,27 +485,9 @@
*/
return -EBUSY;
- for (retry = 5, ret = 0; retry > 0; retry--) {
- sch->schib.pmcw.ena = 0;
- ret = cio_modify(sch);
- if (ret == -ENODEV)
- break;
- if (ret == -EBUSY)
- /*
- * The subchannel is busy or status pending.
- * We'll disable when the next interrupt was delivered
- * via the state machine.
- */
- break;
- if (ret == 0) {
- if (cio_update_schib(sch)) {
- ret = -ENODEV;
- break;
- }
- if (!sch->schib.pmcw.ena)
- break;
- }
- }
+ sch->config.ena = 0;
+ ret = cio_commit_config(sch);
+
sprintf (dbf_txt, "ret:%d", ret);
CIO_TRACE_EVENT (2, dbf_txt);
return ret;
@@ -817,10 +830,9 @@
* enable console I/O-interrupt subclass
*/
isc_register(CONSOLE_ISC);
- console_subchannel.schib.pmcw.isc = CONSOLE_ISC;
- console_subchannel.schib.pmcw.intparm =
- (u32)(addr_t)&console_subchannel;
- ret = cio_modify(&console_subchannel);
+ console_subchannel.config.isc = CONSOLE_ISC;
+ console_subchannel.config.intparm = (u32)(addr_t)&console_subchannel;
+ ret = cio_commit_config(&console_subchannel);
if (ret) {
isc_unregister(CONSOLE_ISC);
console_subchannel_in_use = 0;
@@ -832,8 +844,8 @@
void
cio_release_console(void)
{
- console_subchannel.schib.pmcw.intparm = 0;
- cio_modify(&console_subchannel);
+ console_subchannel.config.intparm = 0;
+ cio_commit_config(&console_subchannel);
isc_unregister(CONSOLE_ISC);
console_subchannel_in_use = 0;
}