ahci: implement aggressive SATA device sleep support

Device Sleep is a feature as described in AHCI 1.3.1 Technical Proposal.
This feature enables an HBA and SATA storage device to enter the DevSleep
interface state, enabling lower power SATA-based systems.

Aggressive Device Sleep enables the HBA to assert the DEVSLP signal as
soon as there are no commands outstanding to the device and the port
specific Device Sleep idle timer has expired. This enables autonomous
entry into the DevSleep interface state without waiting for software
in power sensitive systems.

This patch enables Aggressive Device Sleep only if both host controller
and device support it.

Tested on AMD reference board together with Device Sleep supported device
sample.

Signed-off-by: Shane Huang <shane.huang@amd.com>
Reviewed-by: Aaron Lu <aaron.lwe@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

2 files changed, 13 insertions, 0 deletions

diff --git a/include/linux/ata.h b/include/linux/ata.h
index 47a9dbf0215..408da950217 100644
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -295,6 +295,13 @@ enum {
 
         /* READ_LOG_EXT pages */
         ATA_LOG_SATA_NCQ        = 0x10,
+        ATA_LOG_SATA_ID_DEV_DATA  = 0x30,
+        ATA_LOG_SATA_SETTINGS     = 0x08,
+        ATA_LOG_DEVSLP_MDAT       = 0x30,
+        ATA_LOG_DEVSLP_MDAT_MASK  = 0x1F,
+        ATA_LOG_DEVSLP_DETO       = 0x31,
+        ATA_LOG_DEVSLP_VALID      = 0x37,
+        ATA_LOG_DEVSLP_VALID_MASK = 0x80,
 
         /* READ/WRITE LONG (obsolete) */
         ATA_CMD_READ_LONG       = 0x22,
@@ -348,6 +355,7 @@ enum {
         SATA_FPDMA_IN_ORDER     = 0x04, /* FPDMA in-order data delivery */
         SATA_AN                 = 0x05, /* Asynchronous Notification */
         SATA_SSP                = 0x06, /* Software Settings Preservation */
+        SATA_DEVSLP             = 0x09, /* Device Sleep */
 
         /* feature values for SET_MAX */
         ATA_SET_MAX_ADDR        = 0x00,
@@ -584,6 +592,7 @@ static inline int ata_is_data(u8 prot)
 
 #define ata_id_cdb_intr(id)     (((id)[ATA_ID_CONFIG] & 0x60) == 0x20)
 #define ata_id_has_da(id)       ((id)[ATA_ID_SATA_CAPABILITY_2] & (1 << 4))
+#define ata_id_has_devslp(id)   ((id)[ATA_ID_FEATURE_SUPP] & (1 << 8))
 
 static inline bool ata_id_has_hipm(const u16 *id)
 {
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 64f90e17e51..464e67c2e77 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -162,6 +162,7 @@ enum {
         ATA_DFLAG_DETACHED      = (1 << 25),
 
         ATA_DFLAG_DA            = (1 << 26), /* device supports Device Attention */
+        ATA_DFLAG_DEVSLP        = (1 << 27), /* device supports Device Sleep */
 
         ATA_DEV_UNKNOWN         = 0,    /* unknown device */
         ATA_DEV_ATA             = 1,    /* ATA device */
@@ -649,6 +650,9 @@ struct ata_device {
                 u32             gscr[SATA_PMP_GSCR_DWORDS]; /* PMP GSCR block */
         };
 
+        /* Identify Device Data Log (30h), SATA Settings (page 08h) */
+        u8                      sata_settings[ATA_SECT_SIZE];
+
         /* error history */
         int                     spdn_cnt;
         /* ering is CLEAR_END, read comment above CLEAR_END */