On 2020-05-27 11:42, Cornelia Huck wrote:
On Mon, 18 May 2020 18:07:28 +0200
Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote:
A second step when testing the channel subsystem is to prepare a channel
for use.
This includes:
- Get the current subchannel Information Block (SCHIB) using STSCH
- Update it in memory to set the ENABLE bit
- Tell the CSS that the SCHIB has been modified using MSCH
- Get the SCHIB from the CSS again to verify that the subchannel is
enabled.
- If the subchannel is not enabled retry a predefined retries count.
This tests the MSCH instruction to enable a channel succesfuly.
This is NOT a routine to really enable the channel, no retry is done,
in case of error, a report is made.
Hm... so you retry if the subchannel is not enabled after cc 0, but you
don't retry if the cc indicates busy/status pending? Makes sense, as we
don't expect the subchannel to be busy, but a more precise note in the
patch description would be good :)
OK, I add something like
"
- If the command succeed but subchannel is not enabled retry a
predefined retries count.
- If the command fails, report the failure and do not retry, even
if cc indicates a busy/status as we do not expect this.
"
Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
---
s390x/css.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 67 insertions(+)
diff --git a/s390x/css.c b/s390x/css.c
index d7989d8..1b60a47 100644
--- a/s390x/css.c
+++ b/s390x/css.c
@@ -16,6 +16,7 @@
#include <string.h>
#include <interrupt.h>
#include <asm/arch_def.h>
+#include <asm/time.h>
#include <css.h>
@@ -65,11 +66,77 @@ out:
scn, scn_found, dev_found);
}
+#define MAX_ENABLE_RETRIES 5
+static void test_enable(void)
+{
+ struct pmcw *pmcw = &schib.pmcw;
+ int retry_count = 0;
+ int cc;
+
+ if (!test_device_sid) {
+ report_skip("No device");
+ return;
+ }
+
+ /* Read the SCHIB for this subchannel */
+ cc = stsch(test_device_sid, &schib);
+ if (cc) {
+ report(0, "stsch cc=%d", cc);
+ return;
+ }
+
+ if (pmcw->flags & PMCW_ENABLE) {
+ report(1, "stsch: sch %08x already enabled", test_device_sid);
+ return;
+ }
+
+retry:
+ /* Update the SCHIB to enable the channel */
+ pmcw->flags |= PMCW_ENABLE;
+
+ /* Tell the CSS we want to modify the subchannel */
+ cc = msch(test_device_sid, &schib);
+ if (cc) {
+ /*
+ * If the subchannel is status pending or
+ * if a function is in progress,
+ * we consider both cases as errors.
Could also be cc 3, but that would be even more weird. Just logging the
cc seems fine, though.
+ */
+ report(0, "msch cc=%d", cc);
+ return;
+ }
+
+ /*
+ * Read the SCHIB again to verify the enablement
+ */
+ cc = stsch(test_device_sid, &schib);
+ if (cc) {
+ report(0, "stsch cc=%d", cc);
+ return;
+ }
+
+ if (pmcw->flags & PMCW_ENABLE) {
+ report(1, "msch: sch %08x enabled after %d retries",
+ test_device_sid, retry_count);
+ return;
+ }
+
+ if (retry_count++ < MAX_ENABLE_RETRIES) {
+ mdelay(10); /* the hardware was not ready, let it some time */
s/let/give/
+ goto retry;
+ }
+
+ report(0,
+ "msch: enabling sch %08x failed after %d retries. pmcw: %x",
+ test_device_sid, retry_count, pmcw->flags);
+}
+
static struct {
const char *name;
void (*func)(void);
} tests[] = {
{ "enumerate (stsch)", test_enumerate },
+ { "enable (msch)", test_enable },
{ NULL, NULL }
};
Otherwise,
Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
Thanks a lot.
I make the corrections.
regards,
Pierre
--
Pierre Morel
IBM Lab Boeblingen
