[PATCH v2 23/27] hpsa: disable report lun data caching

[Don Brace <don.brace@pmcs.com>]

From: Scott Teel <scott.teel@pmcs.com>

When external target arrays are present, disable the firmware's
normal behavior of returning a cached copy of the report lun data,
and force it to collect new data each time we request a report luns.

This is necessary for external arrays, since there may be no
reliable signal from the external array to the smart array when
lun configuration changes, and thus when driver requests
report luns, it may be stale data.

Use diag options to turn off RPL data caching.

Reviewed-by: Scott Teel <scott.teel@pmcs.com>
Reviewed-by: Justin Lindley <justin.lindley@pmcs.com>
Reviewed-by: Kevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Don Brace <don.brace@pmcs.com>
---
 drivers/scsi/hpsa.c     |   85 +++++++++++++++++++++++++++++++++++++++++++++++
 drivers/scsi/hpsa_cmd.h |    3 ++
 2 files changed, 88 insertions(+)

diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index acfbbb2..91e7005 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -275,6 +275,7 @@ static int hpsa_scsi_ioaccel_queue_command(struct ctlr_info *h,
 static void hpsa_command_resubmit_worker(struct work_struct *work);
 static u32 lockup_detected(struct ctlr_info *h);
 static int detect_controller_lockup(struct ctlr_info *h);
+static void hpsa_disable_rld_caching(struct ctlr_info *h);
 static int hpsa_luns_changed(struct ctlr_info *h);
 
 static inline struct ctlr_info *sdev_to_hba(struct scsi_device *sdev)
@@ -6380,6 +6381,24 @@ static int fill_cmd(struct CommandList *c, u8 cmd, struct ctlr_info *h,
 			c->Request.CDB[8] = (size >> 8) & 0xFF;
 			c->Request.CDB[9] = size & 0xFF;
 			break;
+		case BMIC_SENSE_DIAG_OPTIONS:
+			c->Request.CDBLen = 16;
+			c->Request.type_attr_dir =
+				TYPE_ATTR_DIR(cmd_type, ATTR_SIMPLE, XFER_READ);
+			c->Request.Timeout = 0;
+			/* Spec says this should be BMIC_WRITE */
+			c->Request.CDB[0] = BMIC_READ;
+			c->Request.CDB[6] = BMIC_SENSE_DIAG_OPTIONS;
+			break;
+		case BMIC_SET_DIAG_OPTIONS:
+			c->Request.CDBLen = 16;
+			c->Request.type_attr_dir =
+					TYPE_ATTR_DIR(cmd_type,
+						ATTR_SIMPLE, XFER_WRITE);
+			c->Request.Timeout = 0;
+			c->Request.CDB[0] = BMIC_WRITE;
+			c->Request.CDB[6] = BMIC_SET_DIAG_OPTIONS;
+			break;
 		case HPSA_CACHE_FLUSH:
 			c->Request.CDBLen = 12;
 			c->Request.type_attr_dir =
@@ -8080,6 +8099,7 @@ static void hpsa_rescan_ctlr_worker(struct work_struct *work)
 		hpsa_scan_start(h->scsi_host);
 		scsi_host_put(h->scsi_host);
 	} else if (h->discovery_polling) {
+		hpsa_disable_rld_caching(h);
 		if (hpsa_luns_changed(h)) {
 			struct Scsi_Host *sh = NULL;
 
@@ -8417,6 +8437,71 @@ out:
 	kfree(flush_buf);
 }
 
+/* Make controller gather fresh report lun data each time we
+ * send down a report luns request
+ */
+static void hpsa_disable_rld_caching(struct ctlr_info *h)
+{
+	u32 *options;
+	struct CommandList *c;
+	int rc;
+
+	/* Don't bother trying to set diag options if locked up */
+	if (unlikely(h->lockup_detected))
+		return;
+
+	options = kzalloc(sizeof(*options), GFP_KERNEL);
+	if (!options) {
+		dev_err(&h->pdev->dev,
+			"Error: failed to disable rld caching, during alloc.\n");
+		return;
+	}
+
+	c = cmd_alloc(h);
+
+	/* first, get the current diag options settings */
+	if (fill_cmd(c, BMIC_SENSE_DIAG_OPTIONS, h, options, 4, 0,
+		RAID_CTLR_LUNID, TYPE_CMD))
+		goto errout;
+
+	rc = hpsa_scsi_do_simple_cmd_with_retry(h, c,
+		PCI_DMA_FROMDEVICE, NO_TIMEOUT);
+	if ((rc != 0) || (c->err_info->CommandStatus != 0))
+		goto errout;
+
+	/* Now, set the bit for disabling the RLD caching */
+	*options |= HPSA_DIAG_OPTS_DISABLE_RLD_CACHING;
+
+	if (fill_cmd(c, BMIC_SET_DIAG_OPTIONS, h, options, 4, 0,
+		RAID_CTLR_LUNID, TYPE_CMD))
+		goto errout;
+
+	rc = hpsa_scsi_do_simple_cmd_with_retry(h, c,
+		PCI_DMA_TODEVICE, NO_TIMEOUT);
+	if ((rc != 0)  || (c->err_info->CommandStatus != 0))
+		goto errout;
+
+	/* Now verify that it got set: */
+	if (fill_cmd(c, BMIC_SENSE_DIAG_OPTIONS, h, options, 4, 0,
+		RAID_CTLR_LUNID, TYPE_CMD))
+		goto errout;
+
+	rc = hpsa_scsi_do_simple_cmd_with_retry(h, c,
+		PCI_DMA_FROMDEVICE, NO_TIMEOUT);
+	if ((rc != 0)  || (c->err_info->CommandStatus != 0))
+		goto errout;
+
+	if (*options && HPSA_DIAG_OPTS_DISABLE_RLD_CACHING)
+		goto out;
+
+errout:
+	dev_err(&h->pdev->dev,
+			"Error: failed to disable report lun data caching.\n");
+out:
+	cmd_free(h, c);
+	kfree(options);
+}
+
 static void hpsa_shutdown(struct pci_dev *pdev)
 {
 	struct ctlr_info *h;
diff --git a/drivers/scsi/hpsa_cmd.h b/drivers/scsi/hpsa_cmd.h
index c83eaf1..4910344 100644
--- a/drivers/scsi/hpsa_cmd.h
+++ b/drivers/scsi/hpsa_cmd.h
@@ -287,6 +287,9 @@ struct SenseSubsystem_info {
 #define BMIC_SENSE_CONTROLLER_PARAMETERS 0x64
 #define BMIC_IDENTIFY_PHYSICAL_DEVICE 0x15
 #define BMIC_IDENTIFY_CONTROLLER 0x11
+#define BMIC_SET_DIAG_OPTIONS 0xF4
+#define BMIC_SENSE_DIAG_OPTIONS 0xF5
+#define HPSA_DIAG_OPTS_DISABLE_RLD_CACHING 0x40000000
 
 /* Command List Structure */
 union SCSI3Addr {