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 +++++++++++++++++++++++++----------------- drivers/s390/cio/cio.c | 17 ++++++++++++++-- drivers/s390/s390mach.c | 17 ++++++++++++++-- drivers/s390/s390mach.h | 3 +++ 5 files changed, 72 insertions(+), 22 deletions(-) (limited to 'drivers/s390') 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); diff --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c index 07a4cbfc243..ad2b3792984 100644 --- a/drivers/s390/cio/cio.c +++ b/drivers/s390/cio/cio.c @@ -646,7 +646,7 @@ do_IRQ (struct pt_regs *regs) * Make sure that the i/o interrupt did not "overtake" * the last HZ timer interrupt. */ - account_ticks(); + account_ticks(S390_lowcore.int_clock); /* * Get interrupt information from lowcore */ @@ -850,6 +850,19 @@ __disable_subchannel_easy(struct subchannel_id schid, struct schib *schib) return -EBUSY; /* uhm... */ } +/* we can't use the normal udelay here, since it enables external interrupts */ + +static void udelay_reset(unsigned long usecs) +{ + uint64_t start_cc, end_cc; + + asm volatile ("STCK %0" : "=m" (start_cc)); + do { + cpu_relax(); + asm volatile ("STCK %0" : "=m" (end_cc)); + } while (((end_cc - start_cc)/4096) < usecs); +} + static inline int __clear_subchannel_easy(struct subchannel_id schid) { @@ -865,7 +878,7 @@ __clear_subchannel_easy(struct subchannel_id schid) if (schid_equal(&ti.schid, &schid)) return 0; } - udelay(100); + udelay_reset(100); } return -EBUSY; } diff --git a/drivers/s390/s390mach.c b/drivers/s390/s390mach.c index 442d6347042..806bb1a921e 100644 --- a/drivers/s390/s390mach.c +++ b/drivers/s390/s390mach.c @@ -15,7 +15,7 @@ #include #include #include - +#include #include #include #include "cio/cio.h" @@ -466,6 +466,19 @@ s390_do_machine_check(struct pt_regs *regs) s390_handle_damage("unable to revalidate registers."); } + if (mci->cd) { + /* Timing facility damage */ + s390_handle_damage("TOD clock damaged"); + } + + if (mci->ed && mci->ec) { + /* External damage */ + if (S390_lowcore.external_damage_code & (1U << ED_ETR_SYNC)) + etr_sync_check(); + if (S390_lowcore.external_damage_code & (1U << ED_ETR_SWITCH)) + etr_switch_to_local(); + } + if (mci->se) /* Storage error uncorrected */ s390_handle_damage("received storage error uncorrected " @@ -504,7 +517,7 @@ static int machine_check_init(void) { init_MUTEX_LOCKED(&m_sem); - ctl_clear_bit(14, 25); /* disable external damage MCH */ + ctl_set_bit(14, 25); /* enable external damage MCH */ ctl_set_bit(14, 27); /* enable system recovery MCH */ #ifdef CONFIG_MACHCHK_WARNING ctl_set_bit(14, 24); /* enable warning MCH */ diff --git a/drivers/s390/s390mach.h b/drivers/s390/s390mach.h index 7abb42a09ae..d3ca4281a49 100644 --- a/drivers/s390/s390mach.h +++ b/drivers/s390/s390mach.h @@ -102,4 +102,7 @@ static inline int stcrw(struct crw *pcrw ) return ccode; } +#define ED_ETR_SYNC 12 /* External damage ETR sync check */ +#define ED_ETR_SWITCH 13 /* External damage ETR switch to local */ + #endif /* __s390mach */ -- cgit v1.2.3