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Date: Wed, 21 Jan 2015 23:40:30 +0100
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>
Cc: lenb@...nel.org, hdegoede@...hat.com, tj@...nel.org, arnd@...db.de,
mjg59@...f.ucam.org, grant.likely@...aro.org,
hanjun.guo@...aro.org, al.stone@...aro.org,
graeme.gregory@...aro.org, leo.duran@....com,
linux-ide@...r.kernel.org, linux-acpi@...r.kernel.org,
linux-kernel@...r.kernel.org, linaro-acpi@...ts.linaro.org
Subject: Re: [V2 PATCH 1/2] ACPI / scan: Add support for ACPI _CLS device matching
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@....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;
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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