[SCSI] libsas: use ->set_dmamode to notify lldds of NCQ parameters

sas_discover_sata() notifies lldds of sata devices twice.  Once to allow
the 'identify' to be sent, and a second time to allow aic94xx (the only
libsas driver that cares about sata_dev.identify) to setup NCQ
parameters before the device becomes known to the midlayer.  Replace
this double notification and intervening 'identify' with an explicit
->lldd_ata_set_dmamode notification.  With this change all ata internal
commands are issued by libata, so we no longer need sas_issue_ata_cmd().

The data from the identify command only needs to be cached in one
location so ata_device.id replaces domain_device.sata_dev.identify.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/aic94xx/aic94xx.h

@@ -80,6 +80,8 @@ void asd_invalidate_edb(struct asd_ascb *ascb, int edb_id);
 
 int  asd_execute_task(struct sas_task *, int num, gfp_t gfp_flags);
 
+void asd_set_dmamode(struct domain_device *dev);
+
 /* ---------- TMFs ---------- */
 int  asd_abort_task(struct sas_task *);
 int  asd_abort_task_set(struct domain_device *, u8 *lun);

drivers/scsi/aic94xx/aic94xx_dev.c

@@ -109,26 +109,37 @@ static int asd_init_sata_tag_ddb(struct domain_device *dev)
 	return 0;
 }
 
-static int asd_init_sata(struct domain_device *dev)
+void asd_set_dmamode(struct domain_device *dev)
 {
 	struct asd_ha_struct *asd_ha = dev->port->ha->lldd_ha;
+	struct ata_device *ata_dev = sas_to_ata_dev(dev);
 	int ddb = (int) (unsigned long) dev->lldd_dev;
 	u32 qdepth = 0;
-	int res = 0;
 
-	asd_ddbsite_write_word(asd_ha, ddb, ATA_CMD_SCBPTR, 0xFFFF);
-	if ((dev->dev_type == SATA_DEV || dev->dev_type == SATA_PM_PORT) &&
-	    dev->sata_dev.identify_device &&
-	    dev->sata_dev.identify_device[10] != 0) {
-		u16 w75 = le16_to_cpu(dev->sata_dev.identify_device[75]);
-		u16 w76 = le16_to_cpu(dev->sata_dev.identify_device[76]);
-
-		if (w76 & 0x100) /* NCQ? */
-			qdepth = (w75 & 0x1F) + 1;
+	if (dev->dev_type == SATA_DEV || dev->dev_type == SATA_PM_PORT) {
+		if (ata_id_has_ncq(ata_dev->id))
+			qdepth = ata_id_queue_depth(ata_dev->id);
 		asd_ddbsite_write_dword(asd_ha, ddb, SATA_TAG_ALLOC_MASK,
 					(1ULL<<qdepth)-1);
 		asd_ddbsite_write_byte(asd_ha, ddb, NUM_SATA_TAGS, qdepth);
 	}
+
+	if (qdepth > 0)
+		if (asd_init_sata_tag_ddb(dev) != 0) {
+			unsigned long flags;
+
+			spin_lock_irqsave(dev->sata_dev.ap->lock, flags);
+			ata_dev->flags |= ATA_DFLAG_NCQ_OFF;
+			spin_unlock_irqrestore(dev->sata_dev.ap->lock, flags);
+		}
+}
+
+static int asd_init_sata(struct domain_device *dev)
+{
+	struct asd_ha_struct *asd_ha = dev->port->ha->lldd_ha;
+	int ddb = (int) (unsigned long) dev->lldd_dev;
+
+	asd_ddbsite_write_word(asd_ha, ddb, ATA_CMD_SCBPTR, 0xFFFF);
 	if (dev->dev_type == SATA_DEV || dev->dev_type == SATA_PM ||
 	    dev->dev_type == SATA_PM_PORT) {
 		struct dev_to_host_fis *fis = (struct dev_to_host_fis *)
@@ -136,9 +147,8 @@ static int asd_init_sata(struct domain_device *dev)
 		asd_ddbsite_write_byte(asd_ha, ddb, SATA_STATUS, fis->status);
 	}
 	asd_ddbsite_write_word(asd_ha, ddb, NCQ_DATA_SCB_PTR, 0xFFFF);
-	if (qdepth > 0)
-		res = asd_init_sata_tag_ddb(dev);
-	return res;
+
+	return 0;
 }
 
 static int asd_init_target_ddb(struct domain_device *dev)

drivers/scsi/aic94xx/aic94xx_init.c

@@ -1009,6 +1009,8 @@ static struct sas_domain_function_template aic94xx_transport_functions = {
 	.lldd_clear_nexus_ha	= asd_clear_nexus_ha,
 
 	.lldd_control_phy	= asd_control_phy,
+
+	.lldd_ata_set_dmamode	= asd_set_dmamode,
 };
 
 static const struct pci_device_id aic94xx_pci_table[] __devinitdata = {