Re: [RFC PATCH 1/2] ACPI / scan: Add support for ACPI _CLS device matching
From: Hanjun Guo
Date: Fri Dec 19 2014 - 09:57:05 EST
Hi Suravee,
On 2014å12æ18æ 07:16, Suravee Suthikulpanit wrote:
From: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
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@xxxxxxx>
---
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))
if handle is not NULL, adev will not NULL too :)
because you get the handle from adev, ACPI_HANDLE() is defined as:
acpi_device_handle(ACPI_COMPANION(dev)), and adev = ACPI_COMPANION(dev);
you may use adev = ACPI_COMPANION(dev) to simplify the code.
+ return ret;
+
+ if (!adev->status.present || !dev_cls)
+ return ret;
+
+ status = acpi_get_handle(adev->handle, METHOD_NAME__CLS, &cls_handle);
do we need this function called here? _CLS is the method under ACPI
device object in DSDT/SSDT, and you will get adev->handle == cls_handle
if I'm not wrong :)
+ 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;
+ }
I think you can evaluate _CLS directly with handle here.
Thanks
Hanjun
+
+ /**
+ * 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;
--
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