1 files changed, 94 insertions, 0 deletions

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 33ac5ea4f531..f2dd99122bd6 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -79,6 +79,8 @@ enum {
          */
         ATA_EH_PRERESET_TIMEOUT         = 10000,
         ATA_EH_FASTDRAIN_INTERVAL       =  3000,
+
+        ATA_EH_UA_TRIES                 = 5,
 };
 
 /* The following table determines how we sequence resets.  Each entry
@@ -1357,6 +1359,37 @@ static int ata_eh_read_log_10h(struct ata_device *dev,
 }
 
 /**
+ *      atapi_eh_tur - perform ATAPI TEST_UNIT_READY
+ *      @dev: target ATAPI device
+ *      @r_sense_key: out parameter for sense_key
+ *
+ *      Perform ATAPI TEST_UNIT_READY.
+ *
+ *      LOCKING:
+ *      EH context (may sleep).
+ *
+ *      RETURNS:
+ *      0 on success, AC_ERR_* mask on failure.
+ */
+static unsigned int atapi_eh_tur(struct ata_device *dev, u8 *r_sense_key)
+{
+        u8 cdb[ATAPI_CDB_LEN] = { TEST_UNIT_READY, 0, 0, 0, 0, 0 };
+        struct ata_taskfile tf;
+        unsigned int err_mask;
+
+        ata_tf_init(dev, &tf);
+
+        tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
+        tf.command = ATA_CMD_PACKET;
+        tf.protocol = ATAPI_PROT_NODATA;
+
+        err_mask = ata_exec_internal(dev, &tf, cdb, DMA_NONE, NULL, 0, 0);
+        if (err_mask == AC_ERR_DEV)
+                *r_sense_key = tf.feature >> 4;
+        return err_mask;
+}
+
+/**
  *      atapi_eh_request_sense - perform ATAPI REQUEST_SENSE
  *      @dev: device to perform REQUEST_SENSE to
  *      @sense_buf: result sense data buffer (SCSI_SENSE_BUFFERSIZE bytes long)
@@ -2774,6 +2807,53 @@ int ata_set_mode(struct ata_link *link, struct ata_device **r_failed_dev)
         return rc;
 }
 
+/**
+ *      atapi_eh_clear_ua - Clear ATAPI UNIT ATTENTION after reset
+ *      @dev: ATAPI device to clear UA for
+ *
+ *      Resets and other operations can make an ATAPI device raise
+ *      UNIT ATTENTION which causes the next operation to fail.  This
+ *      function clears UA.
+ *
+ *      LOCKING:
+ *      EH context (may sleep).
+ *
+ *      RETURNS:
+ *      0 on success, -errno on failure.
+ */
+static int atapi_eh_clear_ua(struct ata_device *dev)
+{
+        int i;
+
+        for (i = 0; i < ATA_EH_UA_TRIES; i++) {
+                u8 sense_buffer[SCSI_SENSE_BUFFERSIZE];
+                u8 sense_key = 0;
+                unsigned int err_mask;
+
+                err_mask = atapi_eh_tur(dev, &sense_key);
+                if (err_mask != 0 && err_mask != AC_ERR_DEV) {
+                        ata_dev_printk(dev, KERN_WARNING, "TEST_UNIT_READY "
+                                "failed (err_mask=0x%x)\n", err_mask);
+                        return -EIO;
+                }
+
+                if (!err_mask || sense_key != UNIT_ATTENTION)
+                        return 0;
+
+                err_mask = atapi_eh_request_sense(dev, sense_buffer, sense_key);
+                if (err_mask) {
+                        ata_dev_printk(dev, KERN_WARNING, "failed to clear "
+                                "UNIT ATTENTION (err_mask=0x%x)\n", err_mask);
+                        return -EIO;
+                }
+        }
+
+        ata_dev_printk(dev, KERN_WARNING,
+                "UNIT ATTENTION persists after %d tries\n", ATA_EH_UA_TRIES);
+
+        return 0;
+}
+
 static int ata_link_nr_enabled(struct ata_link *link)
 {
         struct ata_device *dev;
@@ -3066,6 +3146,20 @@ int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
                         ehc->i.flags &= ~ATA_EHI_SETMODE;
                 }
 
+                /* If reset has been issued, clear UA to avoid
+                 * disrupting the current users of the device.
+                 */
+                if (ehc->i.flags & ATA_EHI_DID_RESET) {
+                        ata_link_for_each_dev(dev, link) {
+                                if (dev->class != ATA_DEV_ATAPI)
+                                        continue;
+                                rc = atapi_eh_clear_ua(dev);
+                                if (rc)
+                                        goto dev_fail;
+                        }
+                }
+
+                /* configure link power saving */
                 if (ehc->i.action & ATA_EH_LPM)
                         ata_link_for_each_dev(dev, link)
                                 ata_dev_enable_pm(dev, ap->pm_policy);