[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>

2 files changed, 41 insertions, 1 deletions

diff --git a/include/linux/ata.h b/include/linux/ata.h
index e21c002c3a4a..128dc7ad4901 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)
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 439d40f86c55..147ccc40c8af 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -133,6 +133,8 @@ enum {
         ATA_DFLAG_ACPI_PENDING  = (1 << 5), /* ACPI resume action pending */
         ATA_DFLAG_ACPI_FAILED   = (1 << 6), /* ACPI on devcfg has failed */
         ATA_DFLAG_AN            = (1 << 7), /* AN configured */
+        ATA_DFLAG_HIPM          = (1 << 8), /* device supports HIPM */
+        ATA_DFLAG_DIPM          = (1 << 9), /* device supports DIPM */
         ATA_DFLAG_CFG_MASK      = (1 << 12) - 1,
 
         ATA_DFLAG_PIO           = (1 << 12), /* device limited to PIO mode */
@@ -186,6 +188,7 @@ enum {
         ATA_FLAG_ACPI_SATA      = (1 << 17), /* need native SATA ACPI layout */
         ATA_FLAG_AN             = (1 << 18), /* controller supports AN */
         ATA_FLAG_PMP            = (1 << 19), /* controller supports PMP */
+        ATA_FLAG_IPM            = (1 << 20), /* driver can handle IPM */
 
         /* The following flag belongs to ap->pflags but is kept in
          * ap->flags because it's referenced in many LLDs and will be
@@ -302,6 +305,7 @@ enum {
         ATA_EHI_RESUME_LINK     = (1 << 1),  /* resume link (reset modifier) */
         ATA_EHI_NO_AUTOPSY      = (1 << 2),  /* no autopsy */
         ATA_EHI_QUIET           = (1 << 3),  /* be quiet */
+        ATA_EHI_LPM             = (1 << 4),  /* link power management action */
 
         ATA_EHI_DID_SOFTRESET   = (1 << 16), /* already soft-reset this port */
         ATA_EHI_DID_HARDRESET   = (1 << 17), /* already soft-reset this port */
@@ -333,6 +337,7 @@ enum {
         ATA_HORKAGE_BROKEN_HPA  = (1 << 4),     /* Broken HPA */
         ATA_HORKAGE_SKIP_PM     = (1 << 5),     /* Skip PM operations */
         ATA_HORKAGE_HPA_SIZE    = (1 << 6),     /* native size off by one */
+        ATA_HORKAGE_IPM         = (1 << 7),     /* Link PM problems */
 
          /* DMA mask for user DMA control: User visible values; DO NOT
             renumber */
@@ -378,6 +383,18 @@ typedef int (*ata_reset_fn_t)(struct ata_link *link, unsigned int *classes,
                               unsigned long deadline);
 typedef void (*ata_postreset_fn_t)(struct ata_link *link, unsigned int *classes);
 
+/*
+ * host pm policy: If you alter this, you also need to alter libata-scsi.c
+ * (for the ascii descriptions)
+ */
+enum link_pm {
+        NOT_AVAILABLE,
+        MIN_POWER,
+        MAX_PERFORMANCE,
+        MEDIUM_POWER,
+};
+extern struct class_device_attribute class_device_attr_link_power_management_policy;
+
 struct ata_ioports {
         void __iomem            *cmd_addr;
         void __iomem            *data_addr;
@@ -624,6 +641,7 @@ struct ata_port {
 
         pm_message_t            pm_mesg;
         int                     *pm_result;
+        enum link_pm            pm_policy;
 
         struct timer_list       fastdrain_timer;
         unsigned long           fastdrain_cnt;
@@ -691,7 +709,8 @@ struct ata_port_operations {
 
         int (*port_suspend) (struct ata_port *ap, pm_message_t mesg);
         int (*port_resume) (struct ata_port *ap);
-
+        int (*enable_pm) (struct ata_port *ap, enum link_pm policy);
+        void (*disable_pm) (struct ata_port *ap);
         int (*port_start) (struct ata_port *ap);
         void (*port_stop) (struct ata_port *ap);