arch/x86/acpi: Add acpi_device_hid

Allow a driver to return device specific _HID, which will be consumed by
acpigen in order to generate proper SSDTs.

Change-Id: Ibb79eb00c008a3c3cdc12ad2a48b88a055a9216f
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35006
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/arch/x86/acpi_device.c

@@ -81,6 +81,24 @@ const char *acpi_device_name(const struct device *dev)
 	return NULL;
 }
 
+/* Locate and return the ACPI _HID (Hardware ID) for this device */
+const char *acpi_device_hid(const struct device *dev)
+{
+	if (!dev)
+		return NULL;
+
+	/* Check for device specific handler */
+	if (dev->ops->acpi_hid)
+		return dev->ops->acpi_hid(dev);
+
+	/*
+	 * Don't walk up the tree to find any parent that can identify this device, as
+	 * PNP devices are hard to identify.
+	 */
+
+	return NULL;
+}
+
 /* Recursive function to find the root device and print a path from there */
 static ssize_t acpi_device_path_fill(const struct device *dev, char *buf,
 				     size_t buf_len, size_t cur)

src/arch/x86/include/arch/acpi_device.h

@@ -63,6 +63,7 @@ struct acpi_dp {
 
 struct device;
 const char *acpi_device_name(const struct device *dev);
+const char *acpi_device_hid(const struct device *dev);
 const char *acpi_device_path(const struct device *dev);
 const char *acpi_device_scope(const struct device *dev);
 const char *acpi_device_path_join(const struct device *dev, const char *name);

src/include/device/device.h

@@ -62,6 +62,8 @@ struct device_operations {
 	void (*acpi_fill_ssdt_generator)(struct device *dev);
 	void (*acpi_inject_dsdt_generator)(struct device *dev);
 	const char *(*acpi_name)(const struct device *dev);
+	/* Returns the optional _HID (Hardware ID) */
+	const char *(*acpi_hid)(const struct device *dev);
 #endif
 	const struct pci_operations *ops_pci;
 	const struct i2c_bus_operations *ops_i2c_bus;