+/*
+ * Build CP for Perform Subsystem Function - SSC.
+ */
+struct dasd_ccw_req *
+dasd_eckd_build_psf_ssc(struct dasd_device *device)
+{
+ struct dasd_ccw_req *cqr;
+ struct dasd_psf_ssc_data *psf_ssc_data;
+ struct ccw1 *ccw;
+
+ cqr = dasd_smalloc_request("ECKD", 1 /* PSF */ ,
+ sizeof(struct dasd_psf_ssc_data),
+ device);
+
+ if (IS_ERR(cqr)) {
+ DEV_MESSAGE(KERN_WARNING, device, "%s",
+ "Could not allocate PSF-SSC request");
+ return cqr;
+ }
+ psf_ssc_data = (struct dasd_psf_ssc_data *)cqr->data;
+ psf_ssc_data->order = PSF_ORDER_SSC;
+ psf_ssc_data->suborder = 0x08;
+
+ ccw = cqr->cpaddr;
+ ccw->cmd_code = DASD_ECKD_CCW_PSF;
+ ccw->cda = (__u32)(addr_t)psf_ssc_data;
+ ccw->count = 66;
+
+ cqr->device = device;
+ cqr->expires = 10*HZ;
+ cqr->buildclk = get_clock();
+ cqr->status = DASD_CQR_FILLED;
+ return cqr;
+}
+
+/*
+ * Perform Subsystem Function.
+ * It is necessary to trigger CIO for channel revalidation since this
+ * call might change behaviour of DASD devices.
+ */
+static int
+dasd_eckd_psf_ssc(struct dasd_device *device)
+{
+ struct dasd_ccw_req *cqr;
+ int rc;
+
+ cqr = dasd_eckd_build_psf_ssc(device);
+ if (IS_ERR(cqr))
+ return PTR_ERR(cqr);
+
+ rc = dasd_sleep_on(cqr);
+ if (!rc)
+ /* trigger CIO to reprobe devices */
+ css_schedule_reprobe();
+ dasd_sfree_request(cqr, cqr->device);
+ return rc;
+}
+
+/*
+ * Valide storage server of current device.
+ */
+static int
+dasd_eckd_validate_server(struct dasd_device *device, struct dasd_uid *uid)
+{
+ int rc;
+
+ /* Currently PAV is the only reason to 'validate' server on LPAR */
+ if (dasd_nopav || MACHINE_IS_VM)
+ return 0;
+
+ rc = dasd_eckd_psf_ssc(device);
+ /* may be requested feature is not available on server,
+ * therefore just report error and go ahead */
+ DEV_MESSAGE(KERN_INFO, device,
+ "PSF-SSC on storage subsystem %s.%s.%04x returned rc=%d",
+ uid->vendor, uid->serial, uid->ssid, rc);
+ /* RE-Read Configuration Data */
+ return dasd_eckd_read_conf(device);
+}
+