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SubjectRe: [V2 PATCH 1/2] ACPI / scan: Add support for ACPI _CLS device matching
Thank you for review comment.  I am sending out V3 with your suggestions.

Suravee

On 01/22/2015 06:40 AM, Rafael J. Wysocki wrote:
> On Monday, January 05, 2015 03:11:14 PM Suravee Suthikulpanit wrote:
>> 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 | 79 +++++++++++++++++++++++++++++++++++++++--
>> include/acpi/acnames.h | 1 +
>> include/linux/acpi.h | 10 ++++++
>> include/linux/device.h | 1 +
>> include/linux/mod_devicetable.h | 6 ++++
>> 5 files changed, 94 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
>> index 16914cc..7b25221 100644
>> --- a/drivers/acpi/scan.c
>> +++ b/drivers/acpi/scan.c
>> @@ -987,13 +987,86 @@ static bool acpi_of_driver_match_device(struct device *dev,
>> bool acpi_driver_match_device(struct device *dev,
>> const struct device_driver *drv)
>> {
>> - if (!drv->acpi_match_table)
>> - return acpi_of_driver_match_device(dev, drv);
>> + bool ret = false;
>>
>> - return !!acpi_match_device(drv->acpi_match_table, dev);
>> + if (drv->acpi_match_table)
>> + ret = !!acpi_match_device(drv->acpi_match_table, dev);
>> +
>> + /* Next, try to match with special "PRP0001" _HID */
>> + if (!ret && drv->of_match_table)
>> + ret = acpi_of_driver_match_device(dev, drv);
>> +
>> + /* Next, try to match with PCI-defined class-code */
>> + if (!ret && drv->acpi_match_cls)
>> + ret = acpi_match_device_cls(drv->acpi_match_cls, dev);
>> +
>> + return ret;
>> }
>> EXPORT_SYMBOL_GPL(acpi_driver_match_device);
>>
>> +/**
>> + * 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 true on success or false on failure.
>> + */
>> +bool acpi_match_device_cls(const struct acpi_device_cls *dev_cls,
>> + const struct device *dev)
>> +{
>> + bool ret = false;
>> + acpi_status status;
>> + 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 };
>> + struct acpi_device *adev = ACPI_COMPANION(dev);
>> + acpi_handle handle = ACPI_HANDLE(dev);
>
> That must be equal to adev->handle, so it is not necessary to use ACPI_HANDLE() here.
>
>> +
>> + if (!handle || !adev || !adev->status.present || !dev_cls)
>> + return ret;
>
> return false;
>
> and set 'ret' later. And if you check 'adev', you don't need to check 'handle'.
> And you can use adev->handle directly below, so the 'handle' variable is not
> necessary.
>
>> +
>> + status = acpi_evaluate_object(handle, METHOD_NAME__CLS, NULL, &buffer);
>> + if (ACPI_FAILURE(status))
>> + return ret;
>
> return false;
>
>> +
>> + /**
>> + * 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");
>
> dev_dbg() here, please.
>
>> + 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"));
>
> I'm not sure how useful that message is going to be to be honest.
>
>> + 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 = true;
>
> ret = dev_cls->base_class == cls.base_class &&
> dev_cls->sub_class == cls.sub_class &&
> dev_cls->prog_interface == cls.prog_interface;
>
>> +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 87f365e..2f2b8ce 100644
>> --- a/include/linux/acpi.h
>> +++ b/include/linux/acpi.h
>> @@ -432,6 +432,10 @@ const struct acpi_device_id *acpi_match_device(const struct acpi_device_id *ids,
>>
>> extern bool acpi_driver_match_device(struct device *dev,
>> const struct device_driver *drv);
>> +
>> +bool acpi_match_device_cls(const struct acpi_device_cls *dev_cls,
>> + const struct device *dev);
>> +
>> int acpi_device_uevent_modalias(struct device *, struct kobj_uevent_env *);
>> int acpi_device_modalias(struct device *, char *, int);
>> void acpi_walk_dep_device_list(acpi_handle handle);
>> @@ -527,6 +531,12 @@ static inline const struct acpi_device_id *acpi_match_device(
>> return NULL;
>> }
>>
>> +static inline bool acpi_match_device_cls(const struct acpi_device_cls *dev_cls,
>> + const struct device *dev)
>> +{
>> + return false;
>> +}
>> +
>> 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 fb50673..8e259c5c 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_match_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 745def8..00e94ec 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;
>> +};
>> +
>
> Move that below the struct acpi_device_id definition.
>
>> struct acpi_device_id {
>> __u8 id[ACPI_ID_LEN];
>> kernel_ulong_t driver_data;
>>
>


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