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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2007-02-05 21:18:19 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2007-02-05 21:18:19 +0100
commitd54853ef8cb17296ac7bce9c77430fb7c80532d0 (patch)
tree649e14d532e17231225a042a7c9a3d9207ad91ee /drivers/s390/block/dasd_eckd.c
parentc1821c2e9711adc3cd298a16b7237c92a2cee78d (diff)
[S390] ETR support.
This patch adds support for clock synchronization to an external time reference (ETR). The external time reference sends an oscillator signal and a synchronization signal every 2^20 microseconds to keep the TOD clocks of all connected servers in sync. For availability two ETR units can be connected to a machine. If the clock deviates for more than the sync-check tolerance all cpus get a machine check that indicates that the clock is out of sync. For the lovely details how to get the clock back in sync see the code below. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'drivers/s390/block/dasd_eckd.c')
-rw-r--r--drivers/s390/block/dasd_eckd.c44
1 files changed, 26 insertions, 18 deletions
diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index d59115cce6dc..a17d73193aab 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -204,37 +204,39 @@ recs_per_track(struct dasd_eckd_characteristics * rdc,
return 0;
}
-static inline void
+static inline int
check_XRC (struct ccw1 *de_ccw,
struct DE_eckd_data *data,
struct dasd_device *device)
{
struct dasd_eckd_private *private;
+ int rc;
private = (struct dasd_eckd_private *) device->private;
+ if (!private->rdc_data.facilities.XRC_supported)
+ return 0;
/* switch on System Time Stamp - needed for XRC Support */
- if (private->rdc_data.facilities.XRC_supported) {
-
- data->ga_extended |= 0x08; /* switch on 'Time Stamp Valid' */
- data->ga_extended |= 0x02; /* switch on 'Extended Parameter' */
-
- data->ep_sys_time = get_clock ();
-
- de_ccw->count = sizeof (struct DE_eckd_data);
- de_ccw->flags |= CCW_FLAG_SLI;
- }
+ data->ga_extended |= 0x08; /* switch on 'Time Stamp Valid' */
+ data->ga_extended |= 0x02; /* switch on 'Extended Parameter' */
- return;
+ rc = get_sync_clock(&data->ep_sys_time);
+ /* Ignore return code if sync clock is switched off. */
+ if (rc == -ENOSYS || rc == -EACCES)
+ rc = 0;
-} /* end check_XRC */
+ de_ccw->count = sizeof (struct DE_eckd_data);
+ de_ccw->flags |= CCW_FLAG_SLI;
+ return rc;
+}
-static inline void
+static inline int
define_extent(struct ccw1 * ccw, struct DE_eckd_data * data, int trk,
int totrk, int cmd, struct dasd_device * device)
{
struct dasd_eckd_private *private;
struct ch_t geo, beg, end;
+ int rc = 0;
private = (struct dasd_eckd_private *) device->private;
@@ -263,12 +265,12 @@ define_extent(struct ccw1 * ccw, struct DE_eckd_data * data, int trk,
case DASD_ECKD_CCW_WRITE_KD_MT:
data->mask.perm = 0x02;
data->attributes.operation = private->attrib.operation;
- check_XRC (ccw, data, device);
+ rc = check_XRC (ccw, data, device);
break;
case DASD_ECKD_CCW_WRITE_CKD:
case DASD_ECKD_CCW_WRITE_CKD_MT:
data->attributes.operation = DASD_BYPASS_CACHE;
- check_XRC (ccw, data, device);
+ rc = check_XRC (ccw, data, device);
break;
case DASD_ECKD_CCW_ERASE:
case DASD_ECKD_CCW_WRITE_HOME_ADDRESS:
@@ -276,7 +278,7 @@ define_extent(struct ccw1 * ccw, struct DE_eckd_data * data, int trk,
data->mask.perm = 0x3;
data->mask.auth = 0x1;
data->attributes.operation = DASD_BYPASS_CACHE;
- check_XRC (ccw, data, device);
+ rc = check_XRC (ccw, data, device);
break;
default:
DEV_MESSAGE(KERN_ERR, device, "unknown opcode 0x%x", cmd);
@@ -312,6 +314,7 @@ define_extent(struct ccw1 * ccw, struct DE_eckd_data * data, int trk,
data->beg_ext.head = beg.head;
data->end_ext.cyl = end.cyl;
data->end_ext.head = end.head;
+ return rc;
}
static inline void
@@ -1200,7 +1203,12 @@ dasd_eckd_build_cp(struct dasd_device * device, struct request *req)
return cqr;
ccw = cqr->cpaddr;
/* First ccw is define extent. */
- define_extent(ccw++, cqr->data, first_trk, last_trk, cmd, device);
+ if (define_extent(ccw++, cqr->data, first_trk,
+ last_trk, cmd, device) == -EAGAIN) {
+ /* Clock not in sync and XRC is enabled. Try again later. */
+ dasd_sfree_request(cqr, device);
+ return ERR_PTR(-EAGAIN);
+ }
/* Build locate_record+read/write/ccws. */
idaws = (unsigned long *) (cqr->data + sizeof(struct DE_eckd_data));
LO_data = (struct LO_eckd_data *) (idaws + cidaw);