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>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index 57eb1c212a4c..6441cbecfa1d 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -115,6 +115,9 @@ enum {
         HOST_CAP2_BOH           = (1 << 0),  /* BIOS/OS handoff supported */
         HOST_CAP2_NVMHCI        = (1 << 1),  /* NVMHCI supported */
         HOST_CAP2_APST          = (1 << 2),  /* Automatic partial to slumber */
+        HOST_CAP2_SDS           = (1 << 3),  /* Support device sleep */
+        HOST_CAP2_SADM          = (1 << 4),  /* Support aggressive DevSlp */
+        HOST_CAP2_DESO          = (1 << 5),  /* DevSlp from slumber only */
 
         /* registers for each SATA port */
         PORT_LST_ADDR           = 0x00, /* command list DMA addr */
@@ -133,6 +136,7 @@ enum {
         PORT_SCR_ACT            = 0x34, /* SATA phy register: SActive */
         PORT_SCR_NTF            = 0x3c, /* SATA phy register: SNotification */
         PORT_FBS                = 0x40, /* FIS-based Switching */
+        PORT_DEVSLP             = 0x44, /* device sleep */
 
         /* PORT_IRQ_{STAT,MASK} bits */
         PORT_IRQ_COLD_PRES      = (1 << 31), /* cold presence detect */
@@ -186,6 +190,7 @@ enum {
         PORT_CMD_ICC_PARTIAL    = (0x2 << 28), /* Put i/f in partial state */
         PORT_CMD_ICC_SLUMBER    = (0x6 << 28), /* Put i/f in slumber state */
 
+        /* PORT_FBS bits */
         PORT_FBS_DWE_OFFSET     = 16, /* FBS device with error offset */
         PORT_FBS_ADO_OFFSET     = 12, /* FBS active dev optimization offset */
         PORT_FBS_DEV_OFFSET     = 8,  /* FBS device to issue offset */
@@ -194,6 +199,15 @@ enum {
         PORT_FBS_DEC            = (1 << 1), /* FBS device error clear */
         PORT_FBS_EN             = (1 << 0), /* Enable FBS */
 
+        /* PORT_DEVSLP bits */
+        PORT_DEVSLP_DM_OFFSET   = 25,             /* DITO multiplier offset */
+        PORT_DEVSLP_DM_MASK     = (0xf << 25),    /* DITO multiplier mask */
+        PORT_DEVSLP_DITO_OFFSET = 15,             /* DITO offset */
+        PORT_DEVSLP_MDAT_OFFSET = 10,             /* Minimum assertion time */
+        PORT_DEVSLP_DETO_OFFSET = 2,              /* DevSlp exit timeout */
+        PORT_DEVSLP_DSP         = (1 << 1),       /* DevSlp present */
+        PORT_DEVSLP_ADSE        = (1 << 0),       /* Aggressive DevSlp enable */
+
         /* hpriv->flags bits */
 
 #define AHCI_HFLAGS(flags)              .private_data   = (void *)(flags)