[libata] Link power management infrastructure

Device Initiated Power Management, which is defined
in SATA 2.5 can be enabled for disks which support it.
This patch enables DIPM when the user sets the link
power management policy to "min_power".

Additionally, libata drivers can define a function
(enable_pm) that will perform hardware specific actions to
enable whatever power management policy the user set up
for Host Initiated Power management (HIPM).
This power management policy will be activated after all
disks have been enumerated and intialized.  Drivers should
also define disable_pm, which will turn off link power
management, but not change link power management policy.

Documentation/scsi/link_power_management_policy.txt has additional
information.

Signed-off-by:  Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/include/linux/ata.h b/include/linux/ata.h
index e21c002..128dc7a 100644
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -236,6 +236,7 @@ enum {
 
 	/* SETFEATURE Sector counts for SATA features */
 	SATA_AN			= 0x05,  /* Asynchronous Notification */
+	SATA_DIPM		= 0x03,  /* Device Initiated Power Management */
 
 	/* ATAPI stuff */
 	ATAPI_PKT_DMA		= (1 << 0),
@@ -378,6 +379,26 @@ struct ata_taskfile {
 
 #define ata_id_cdb_intr(id)	(((id)[0] & 0x60) == 0x20)
 
+static inline bool ata_id_has_hipm(const u16 *id)
+{
+	u16 val = id[76];
+
+	if (val == 0 || val == 0xffff)
+		return false;
+
+	return val & (1 << 9);
+}
+
+static inline bool ata_id_has_dipm(const u16 *id)
+{
+	u16 val = id[78];
+
+	if (val == 0 || val == 0xffff)
+		return false;
+
+	return val & (1 << 3);
+}
+
 static inline int ata_id_has_fua(const u16 *id)
 {
 	if ((id[84] & 0xC000) != 0x4000)