scsi: ata: Use ACPI methods to power on disks

Some embedded devices have the ability to control whether power is
provided to the disks via the SATA power connector or not. If power
resources are defined on ATA ports / devices in ACPI, we should try to
set the power state to D0 before probing the disk to ensure that any
power supply or power gate that may exist is providing power to the
disk.

An example for such devices would be newer synology NAS devices. Every
disk slot has its own SATA power connector. Whether the connector is
providing power is controlled via an gpio, which is *off by default*.
Also the disk loses power on reboots.

Add a new function, ata_acpi_port_power_on(), that will be used to power
on the SATA power connector if usable ACPI power resources on the
associated ATA port / device are found. It will be called right before
probing the port, therefore the disk will be powered on just in time.

Signed-off-by: Markus Probst <markus.probst@posteo.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://patch.msgid.link/20251104142413.322347-3-markus.probst@posteo.de
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 41 insertions, 0 deletions

diff --git a/drivers/ata/libata-acpi.c b/drivers/ata/libata-acpi.c
index f2140fc06ba0..4782e0f22d7f 100644
--- a/drivers/ata/libata-acpi.c
+++ b/drivers/ata/libata-acpi.c
@@ -246,6 +246,47 @@ void ata_acpi_bind_dev(struct ata_device *dev)
 }
 
 /**
+ * ata_acpi_port_power_on - set the power state of the ata port to D0
+ * @ap: target ATA port
+ *
+ * This function is called at the beginning of ata_port_probe().
+ */
+void ata_acpi_port_power_on(struct ata_port *ap)
+{
+	acpi_handle handle;
+	int i;
+
+	/*
+	 * If ATA_FLAG_ACPI_SATA is set, the acpi fwnode is attached to the
+	 * ata_device instead of the ata_port.
+	 */
+	if (ap->flags & ATA_FLAG_ACPI_SATA) {
+		for (i = 0; i < ATA_MAX_DEVICES; i++) {
+			struct ata_device *dev = &ap->link.device[i];
+
+			if (!is_acpi_device_node(dev->tdev.fwnode))
+				continue;
+			handle = ACPI_HANDLE(&dev->tdev);
+			if (!acpi_bus_power_manageable(handle))
+				continue;
+			if (acpi_bus_set_power(handle, ACPI_STATE_D0))
+				ata_dev_err(dev,
+					    "acpi: failed to set power state to D0\n");
+		}
+		return;
+	}
+
+	if (!is_acpi_device_node(ap->tdev.fwnode))
+		return;
+	handle = ACPI_HANDLE(&ap->tdev);
+	if (!acpi_bus_power_manageable(handle))
+		return;
+
+	if (acpi_bus_set_power(handle, ACPI_STATE_D0))
+		ata_port_err(ap, "acpi: failed to set power state to D0\n");
+}
+
+/**
  * ata_acpi_dissociate - dissociate ATA host from ACPI objects
  * @host: target ATA host
  *