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>

drivers/ata/libata-acpi.c

@@ -775,6 +775,36 @@ 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

drivers/ata/libata-eh.c

@@ -2747,6 +2747,7 @@ static void ata_eh_handle_port_suspend(struct ata_port *ap)
 	if (ap->ops->port_suspend)
 		rc = ap->ops->port_suspend(ap, ap->pm_mesg);
 
+	ata_acpi_set_state(ap, PMSG_SUSPEND);
  out:
 	/* report result */
 	spin_lock_irqsave(ap->lock, flags);
@@ -2792,6 +2793,8 @@ static void ata_eh_handle_port_resume(struct ata_port *ap)
 
 	WARN_ON(!(ap->pflags & ATA_PFLAG_SUSPENDED));
 
+	ata_acpi_set_state(ap, PMSG_ON);
+
 	if (ap->ops->port_resume)
 		rc = ap->ops->port_resume(ap);
 

drivers/ata/libata.h

@@ -114,6 +114,7 @@ extern int ata_acpi_on_suspend(struct ata_port *ap);
 extern void ata_acpi_on_resume(struct ata_port *ap);
 extern int ata_acpi_on_devcfg(struct ata_device *dev);
 extern void ata_acpi_on_disable(struct ata_device *dev);
+extern void ata_acpi_set_state(struct ata_port *ap, pm_message_t state);
 #else
 static inline void ata_acpi_associate_sata_port(struct ata_port *ap) { }
 static inline void ata_acpi_associate(struct ata_host *host) { }
@@ -122,6 +123,8 @@ static inline int ata_acpi_on_suspend(struct ata_port *ap) { return 0; }
 static inline void ata_acpi_on_resume(struct ata_port *ap) { }
 static inline int ata_acpi_on_devcfg(struct ata_device *dev) { return 0; }
 static inline void ata_acpi_on_disable(struct ata_device *dev) { }
+static inline void ata_acpi_set_state(struct ata_port *ap,
+				      pm_message_t state) { }
 #endif
 
 /* libata-scsi.c */