libata-acpi: add ACPI _PSx method

ACPI spec (ver 3.0a, p289) requires IDE power on/off executes ACPI _PSx
methods. As recently most PATA drivers use libata, this patch adds _PSx
method support in libata. ACPI spec doesn't mention if SATA requires the
same _PSx method.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Acked-by: Len Brown <len.brown@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/drivers/ata/libata-acpi.c b/drivers/ata/libata-acpi.c
index 7bf4befd96bc..ebc4dfcf2f19 100644
--- a/drivers/ata/libata-acpi.c
+++ b/drivers/ata/libata-acpi.c
@@ -776,6 +776,36 @@ void ata_acpi_on_resume(struct ata_port *ap)
 }
 
 /**
+ * ata_acpi_set_state - set the port power state
+ * @ap: target ATA port
+ * @state: state, on/off
+ *
+ * This function executes the _PS0/_PS3 ACPI method to set the power state.
+ * ACPI spec requires _PS0 when IDE power on and _PS3 when power off
+ */
+void ata_acpi_set_state(struct ata_port *ap, pm_message_t state)
+{
+        struct ata_device *dev;
+
+        if (!ap->acpi_handle || (ap->flags & ATA_FLAG_ACPI_SATA))
+                return;
+
+        /* channel first and then drives for power on and vica versa
+           for power off */
+        if (state.event == PM_EVENT_ON)
+                acpi_bus_set_power(ap->acpi_handle, ACPI_STATE_D0);
+
+        ata_link_for_each_dev(dev, &ap->link) {
+                if (dev->acpi_handle && ata_dev_enabled(dev))
+                        acpi_bus_set_power(dev->acpi_handle,
+                                state.event == PM_EVENT_ON ?
+                                        ACPI_STATE_D0 : ACPI_STATE_D3);
+        }
+        if (state.event != PM_EVENT_ON)
+                acpi_bus_set_power(ap->acpi_handle, ACPI_STATE_D3);
+}
+
+/**
  * ata_acpi_on_devcfg - ATA ACPI hook called on device donfiguration
  * @dev: target ATA device
  *