libata: Handle drives that require a spin-up command before first access

(S)ATA drives can be configured for "power-up in standby",
a mode whereby a specific "spin up now!" command is required
before the first media access.

Currently, a drive with this feature enabled can not be used at all
with libata, and once in this mode, the drive becomes a doorstop.

The older drivers/ide subsystem at least enumerates the drive,
so that it can be woken up after the fact from a userspace HDIO_*
command, but not libata.

This patch adds support to libata for the "power-up in standby"
mode where a "spin up now!" command (SET_FEATURES) is needed.
With this, libata will recognize such drives, spin them up,
and then re-IDENTIFY them if necessary to get a full/complete
set of drive features data.

Drives in this state are determined by looking for
special values in id[2], as documented in the current ATA specs.

Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 27 insertions, 1 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 6d0a946afe84..227399e48470 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1649,13 +1649,13 @@ int ata_dev_read_id(struct ata_device *dev, unsigned int *p_class,
         struct ata_taskfile tf;
         unsigned int err_mask = 0;
         const char *reason;
+        int tried_spinup = 0;
         int rc;
 
         if (ata_msg_ctl(ap))
                 ata_dev_printk(dev, KERN_DEBUG, "%s: ENTER\n", __FUNCTION__);
 
         ata_dev_select(ap, dev->devno, 1, 1); /* select device 0/1 */
-
  retry:
         ata_tf_init(dev, &tf);
 
@@ -1712,6 +1712,32 @@ int ata_dev_read_id(struct ata_device *dev, unsigned int *p_class,
                         goto err_out;
         }
 
+        if (!tried_spinup && (id[2] == 0x37c8 || id[2] == 0x738c)) {
+                tried_spinup = 1;
+                /*
+                 * Drive powered-up in standby mode, and requires a specific
+                 * SET_FEATURES spin-up subcommand before it will accept
+                 * anything other than the original IDENTIFY command.
+                 */
+                ata_tf_init(dev, &tf);
+                tf.command = ATA_CMD_SET_FEATURES;
+                tf.feature = SETFEATURES_SPINUP;
+                tf.protocol = ATA_PROT_NODATA;
+                tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
+                err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0);
+                if (err_mask) {
+                        rc = -EIO;
+                        reason = "SPINUP failed";
+                        goto err_out;
+                }
+                /*
+                 * If the drive initially returned incomplete IDENTIFY info,
+                 * we now must reissue the IDENTIFY command.
+                 */
+                if (id[2] == 0x37c8)
+                        goto retry;
+        }
+
         if ((flags & ATA_READID_POSTRESET) && class == ATA_DEV_ATA) {
                 /*
                  * The exact sequence expected by certain pre-ATA4 drives is: