From d54853ef8cb17296ac7bce9c77430fb7c80532d0 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Mon, 5 Feb 2007 21:18:19 +0100 Subject: [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 --- drivers/s390/block/dasd.c | 13 +++++++++++++ drivers/s390/block/dasd_eckd.c | 44 +++++++++++++++++++++++++----------------- 2 files changed, 39 insertions(+), 18 deletions(-) (limited to 'drivers/s390/block') diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c index f208940c463..555e18a6b78 100644 --- a/drivers/s390/block/dasd.c +++ b/drivers/s390/block/dasd.c @@ -1232,6 +1232,19 @@ __dasd_process_blk_queue(struct dasd_device * device) if (IS_ERR(cqr)) { if (PTR_ERR(cqr) == -ENOMEM) break; /* terminate request queue loop */ + if (PTR_ERR(cqr) == -EAGAIN) { + /* + * The current request cannot be build right + * now, we have to try later. If this request + * is the head-of-queue we stop the device + * for 1/2 second. + */ + if (!list_empty(&device->ccw_queue)) + break; + device->stopped |= DASD_STOPPED_PENDING; + dasd_set_timer(device, HZ/2); + break; + } DBF_DEV_EVENT(DBF_ERR, device, "CCW creation failed (rc=%ld) " "on request %p", diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c index d59115cce6d..a17d73193aa 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); -- cgit v1.2.3