[SCSI] libsas: Add option for SATA soft reset

This allows a libsas driver to optionally provide a soft reset handler
for libata to drive.  The isci driver allows software to control the
assertion/deassertion of SRST.

[jejb: checkpatch.pl fixes]
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <jbottomley@parallels.com>

2 files changed, 40 insertions, 1 deletions

diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
index e99301421409..db9238f2ecb8 100644
--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -295,6 +295,44 @@ static int sas_ata_hard_reset(struct ata_link *link, unsigned int *class,
         return ret;
 }
 
+static int sas_ata_soft_reset(struct ata_link *link, unsigned int *class,
+                               unsigned long deadline)
+{
+        struct ata_port *ap = link->ap;
+        struct domain_device *dev = ap->private_data;
+        struct sas_internal *i =
+                to_sas_internal(dev->port->ha->core.shost->transportt);
+        int res = TMF_RESP_FUNC_FAILED;
+        int ret = 0;
+
+        if (i->dft->lldd_ata_soft_reset)
+                res = i->dft->lldd_ata_soft_reset(dev);
+
+        if (res != TMF_RESP_FUNC_COMPLETE) {
+                SAS_DPRINTK("%s: Unable to soft reset\n", __func__);
+                ret = -EAGAIN;
+        }
+
+        switch (dev->sata_dev.command_set) {
+        case ATA_COMMAND_SET:
+                SAS_DPRINTK("%s: Found ATA device.\n", __func__);
+                *class = ATA_DEV_ATA;
+                break;
+        case ATAPI_COMMAND_SET:
+                SAS_DPRINTK("%s: Found ATAPI device.\n", __func__);
+                *class = ATA_DEV_ATAPI;
+                break;
+        default:
+                SAS_DPRINTK("%s: Unknown SATA command set: %d.\n",
+                            __func__, dev->sata_dev.command_set);
+                *class = ATA_DEV_UNKNOWN;
+                break;
+        }
+
+        ap->cbl = ATA_CBL_SATA;
+        return ret;
+}
+
 static void sas_ata_post_internal(struct ata_queued_cmd *qc)
 {
         if (qc->flags & ATA_QCFLAG_FAILED)
@@ -325,7 +363,7 @@ static void sas_ata_post_internal(struct ata_queued_cmd *qc)
 
 static struct ata_port_operations sas_sata_ops = {
         .prereset               = ata_std_prereset,
-        .softreset              = NULL,
+        .softreset              = sas_ata_soft_reset,
         .hardreset              = sas_ata_hard_reset,
         .postreset              = ata_std_postreset,
         .error_handler          = ata_std_error_handler,
diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
index 8f6bb9c7f3eb..ee866060f8a4 100644
--- a/include/scsi/libsas.h
+++ b/include/scsi/libsas.h
@@ -604,6 +604,7 @@ struct sas_domain_function_template {
         int (*lldd_clear_aca)(struct domain_device *, u8 *lun);
         int (*lldd_clear_task_set)(struct domain_device *, u8 *lun);
         int (*lldd_I_T_nexus_reset)(struct domain_device *);
+        int (*lldd_ata_soft_reset)(struct domain_device *);
         int (*lldd_lu_reset)(struct domain_device *, u8 *lun);
         int (*lldd_query_task)(struct sas_task *);