From: Suravee Suthikulpanit Suravee.Suthikulpanit@amd.com
Device drivers typically use ACPI _HIDs/_CIDs listed in struct device_driver acpi_match_table to match devices. However, for generic drivers, we do not want to list _HID for all supported devices, and some device classes do not have _CID (e.g. SATA, USB). Instead, we can leverage ACPI _CLS, which specifies PCI-defined class code (i.e. base-class, subclass and programming interface).
This patch adds support for matching ACPI devices using the _CLS method.
Signed-off-by: Suravee Suthikulpanit Suravee.Suthikulpanit@amd.com --- drivers/acpi/scan.c | 73 +++++++++++++++++++++++++++++++++++++++++ include/acpi/acnames.h | 1 + include/linux/acpi.h | 12 ++++++- include/linux/device.h | 1 + include/linux/mod_devicetable.h | 6 ++++ 5 files changed, 92 insertions(+), 1 deletion(-)
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index d670158..6406648 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -864,6 +864,79 @@ int acpi_match_device_ids(struct acpi_device *device, } EXPORT_SYMBOL(acpi_match_device_ids);
+/** + * acpi_match_device_cls - Match a struct device against a ACPI _CLS method + * @dev_cls: A pointer to struct acpi_device_cls object to match against. + * @dev: The ACPI device structure to match. + * + * Check if @dev has a valid ACPI and _CLS handle. If there is a + * struct acpi_device_cls object for that handle, use that object to match + * against the given struct acpi_device_cls object. + * + * Return 0 on success or error code on failure. + */ +int acpi_match_device_cls(const struct acpi_device_cls *dev_cls, + const struct device *dev) +{ + int ret = -EINVAL; + acpi_status status; + struct acpi_device *adev; + union acpi_object *pkg; + struct acpi_device_cls cls; + struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; + struct acpi_buffer format = { sizeof("NNN"), "NNN" }; + struct acpi_buffer state = { 0, NULL }; + acpi_handle handle = ACPI_HANDLE(dev); + acpi_handle cls_handle; + + if (!handle || acpi_bus_get_device(handle, &adev)) + return ret; + + if (!adev->status.present || !dev_cls) + return ret; + + status = acpi_get_handle(adev->handle, METHOD_NAME__CLS, &cls_handle); + if (ACPI_FAILURE(status)) + return ret; + + status = acpi_evaluate_object(cls_handle, "_CLS", NULL, &buffer); + if (ACPI_FAILURE(status)) { + ACPI_EXCEPTION((AE_INFO, status, "Failed to Evaluat _CLS")); + return ret; + } + + /** + * Note: + * ACPIv5.1 defines the package to contain 3 integers for + * Base-Class code, Sub-Class code, and Programming Interface code. + */ + pkg = buffer.pointer; + if (!pkg || + (pkg->type != ACPI_TYPE_PACKAGE) || + (pkg->package.count != 3)) { + dev_err(&adev->dev, "Invalid _CLS data\n"); + goto out; + } + + state.length = sizeof(struct acpi_device_cls); + state.pointer = &cls; + + status = acpi_extract_package(pkg, &format, &state); + if (ACPI_FAILURE(status)) { + ACPI_EXCEPTION((AE_INFO, status, "Invalid data")); + goto out; + } + + if ((dev_cls->base_class == cls.base_class) && + (dev_cls->sub_class == cls.sub_class) && + (dev_cls->prog_interface == cls.prog_interface)) + ret = 0; +out: + kfree(buffer.pointer); + return ret; +} +EXPORT_SYMBOL_GPL(acpi_match_device_cls); + static void acpi_free_power_resources_lists(struct acpi_device *device) { int i; diff --git a/include/acpi/acnames.h b/include/acpi/acnames.h index 7461327..22332a6 100644 --- a/include/acpi/acnames.h +++ b/include/acpi/acnames.h @@ -51,6 +51,7 @@ #define METHOD_NAME__BBN "_BBN" #define METHOD_NAME__CBA "_CBA" #define METHOD_NAME__CID "_CID" +#define METHOD_NAME__CLS "_CLS" #define METHOD_NAME__CRS "_CRS" #define METHOD_NAME__DDN "_DDN" #define METHOD_NAME__HID "_HID" diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 5a92d49..8680afa 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -428,10 +428,14 @@ extern int acpi_nvs_for_each_region(int (*func)(__u64, __u64, void *), const struct acpi_device_id *acpi_match_device(const struct acpi_device_id *ids, const struct device *dev);
+int acpi_match_device_cls(const struct acpi_device_cls *dev_cls, + const struct device *dev); + static inline bool acpi_driver_match_device(struct device *dev, const struct device_driver *drv) { - return !!acpi_match_device(drv->acpi_match_table, dev); + return (!!acpi_match_device(drv->acpi_match_table, dev) || + !acpi_match_device_cls(drv->acpi_cls, dev)); }
int acpi_device_uevent_modalias(struct device *, struct kobj_uevent_env *); @@ -511,6 +515,12 @@ static inline const struct acpi_device_id *acpi_match_device( return NULL; }
+static int acpi_match_device_cls(const struct acpi_device_cls *dev_cls, + const struct device *dev) +{ + return -EINVAL; +} + static inline bool acpi_driver_match_device(struct device *dev, const struct device_driver *drv) { diff --git a/include/linux/device.h b/include/linux/device.h index ce1f2160..a469adc 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -237,6 +237,7 @@ struct device_driver {
const struct of_device_id *of_match_table; const struct acpi_device_id *acpi_match_table; + const struct acpi_device_cls *acpi_cls;
int (*probe) (struct device *dev); int (*remove) (struct device *dev); diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h index 44eeef0..f2ef3c6 100644 --- a/include/linux/mod_devicetable.h +++ b/include/linux/mod_devicetable.h @@ -186,6 +186,12 @@ struct css_device_id {
#define ACPI_ID_LEN 9
+struct acpi_device_cls { + kernel_ulong_t base_class; + kernel_ulong_t sub_class; + kernel_ulong_t prog_interface; +}; + struct acpi_device_id { __u8 id[ACPI_ID_LEN]; kernel_ulong_t driver_data;