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, 2 insertions, 0 deletions

diff --git a/include/linux/ata.h b/include/linux/ata.h
index f4dc8dfeadc2..edb31bfff68f 100644
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -202,6 +202,8 @@ enum {
         SETFEATURES_WC_ON       = 0x02, /* Enable write cache */
         SETFEATURES_WC_OFF      = 0x82, /* Disable write cache */
 
+        SETFEATURES_SPINUP      = 0x07, /* Spin-up drive */
+
         /* ATAPI stuff */
         ATAPI_PKT_DMA           = (1 << 0),
         ATAPI_DMADIR            = (1 << 2),     /* ATAPI data dir: