[V5 PATCH 1/2] ACPI / scan: Add support for ACPI _CLS device matching

Suravee Suthikulpanit
2015-03-06T06:27:02Z

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. Also, certain classes of devices
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.

To support loadable module, current design uses _HID or _CID to match device's
modalias. With the new way of matching with _CLS this would requires modification
to the current ACPI modalias key to include _CLS. This patch appends PCI-defined
class-code to the existing ACPI modalias as following.

acpi:<HID>:<CID1>:<CID2>:..:<CIDn>:<bbsspp>:
E.g:
# cat /sys/devices/platform/AMDI0600:00/modalias
acpi:AMDI0600:010601:

where bb is th base-class code, ss is te sub-class code, and pp is the
programming interface code

Since there would not be _HID/_CID in the ACPI matching table of the driver,
this patch adds a field to acpi_device_id to specify the matching _CLS.

static const struct acpi_device_id ahci_acpi_match[] = {
{ "", 0, PCI_CLASS_STORAGE_SATA_AHCI },
{},
};

In this case, the corresponded entry in modules.alias file would be:

alias acpi*:010601:* ahci_platform

Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
---
drivers/acpi/acpica/acutils.h | 3 ++
drivers/acpi/acpica/nsxfname.c | 21 ++++++++++--
drivers/acpi/acpica/utids.c | 71 +++++++++++++++++++++++++++++++++++++++
drivers/acpi/scan.c | 17 ++++++++--
include/acpi/acnames.h | 1 +
include/acpi/actypes.h | 4 ++-
include/linux/mod_devicetable.h | 1 +
scripts/mod/devicetable-offsets.c | 1 +
scripts/mod/file2alias.c | 13 +++++--
9 files changed, 124 insertions(+), 8 deletions(-)

diff --git a/drivers/acpi/acpica/acutils.h b/drivers/acpi/acpica/acutils.h
index c2f03e8..2aef850 100644
--- a/drivers/acpi/acpica/acutils.h
+++ b/drivers/acpi/acpica/acutils.h
@@ -430,6 +430,9 @@ acpi_status
acpi_ut_execute_CID(struct acpi_namespace_node *device_node,
struct acpi_pnp_device_id_list ** return_cid_list);

+acpi_status
+acpi_ut_execute_CLS(struct acpi_namespace_node *device_node,
+ struct acpi_pnp_device_id **return_id);
/*
* utlock - reader/writer locks
*/
diff --git a/drivers/acpi/acpica/nsxfname.c b/drivers/acpi/acpica/nsxfname.c
index d66c326..590ef06 100644
--- a/drivers/acpi/acpica/nsxfname.c
+++ b/drivers/acpi/acpica/nsxfname.c
@@ -276,11 +276,12 @@ acpi_get_object_info(acpi_handle handle,
struct acpi_pnp_device_id *hid = NULL;
struct acpi_pnp_device_id *uid = NULL;
struct acpi_pnp_device_id *sub = NULL;
+ struct acpi_pnp_device_id *cls = NULL;
char *next_id_string;
acpi_object_type type;
acpi_name name;
u8 param_count = 0;
- u8 valid = 0;
+ u16 valid = 0;
u32 info_size;
u32 i;
acpi_status status;
@@ -320,7 +321,7 @@ acpi_get_object_info(acpi_handle handle,
if ((type == ACPI_TYPE_DEVICE) || (type == ACPI_TYPE_PROCESSOR)) {
/*
* Get extra info for ACPI Device/Processor objects only:
- * Run the Device _HID, _UID, _SUB, and _CID methods.
+ * Run the Device _HID, _UID, _SUB, _CID and _CLS methods.
*
* Note: none of these methods are required, so they may or may
* not be present for this device. The Info->Valid bitfield is used
@@ -351,6 +352,14 @@ acpi_get_object_info(acpi_handle handle,
valid |= ACPI_VALID_SUB;
}

+ /* Execute the Device._CLS method */
+
+ status = acpi_ut_execute_CLS(node, &cls);
+ if (ACPI_SUCCESS(status)) {
+ info_size += cls->length;
+ valid |= ACPI_VALID_CLS;
+ }
+
/* Execute the Device._CID method */

status = acpi_ut_execute_CID(node, &cid_list);
@@ -468,6 +477,11 @@ acpi_get_object_info(acpi_handle handle,
sub, next_id_string);
}

+ if (cls) {
+ next_id_string = acpi_ns_copy_device_id(&info->cls,
+ cls, next_id_string);
+ }
+
if (cid_list) {
info->compatible_id_list.count = cid_list->count;
info->compatible_id_list.list_size = cid_list->list_size;
@@ -507,6 +521,9 @@ cleanup:
if (sub) {
ACPI_FREE(sub);
}
+ if (cls) {
+ ACPI_FREE(cls);
+ }
if (cid_list) {
ACPI_FREE(cid_list);
}
diff --git a/drivers/acpi/acpica/utids.c b/drivers/acpi/acpica/utids.c
index 27431cf..a64b5d1 100644
--- a/drivers/acpi/acpica/utids.c
+++ b/drivers/acpi/acpica/utids.c
@@ -416,3 +416,74 @@ cleanup:
acpi_ut_remove_reference(obj_desc);
return_ACPI_STATUS(status);
}
+
+/*******************************************************************************
+ *
+ * FUNCTION: acpi_ut_execute_CLS
+ *
+ * PARAMETERS: device_node - Node for the device
+ * return_id - Where the string UID is returned
+ *
+ * RETURN: Status
+ *
+ * DESCRIPTION: Executes the _CLS control method that returns PCI-defined
+ * class code of the device. The ACPI spec define _CLS as a
+ * package with three integers. The returned string has format:
+ *
+ * "bbsspp"
+ * where:
+ * bb = Base-class code
+ * ss = Sub-class code
+ * pp = Programming Interface code
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_ut_execute_CLS(struct acpi_namespace_node *device_node,
+ struct acpi_pnp_device_id **return_id)
+{
+ struct acpi_pnp_device_id *cls;
+ union acpi_operand_object *obj_desc;
+ union acpi_operand_object **cls_objects;
+ acpi_status status;
+
+ ACPI_FUNCTION_TRACE(ut_execute_CLS);
+ status = acpi_ut_evaluate_object(device_node, METHOD_NAME__CLS,
+ ACPI_BTYPE_PACKAGE, &obj_desc);
+ if (ACPI_FAILURE(status))
+ return_ACPI_STATUS(status);
+
+ cls_objects = obj_desc->package.elements;
+
+ if (obj_desc->common.type == ACPI_TYPE_PACKAGE &&
+ obj_desc->package.count == 3 &&
+ cls_objects[0]->common.type == ACPI_TYPE_INTEGER &&
+ cls_objects[1]->common.type == ACPI_TYPE_INTEGER &&
+ cls_objects[2]->common.type == ACPI_TYPE_INTEGER) {
+
+ /* Allocate a buffer for the CLS */
+ cls = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_pnp_device_id) +
+ (acpi_size) 7);
+ if (!cls) {
+ status = AE_NO_MEMORY;
+ goto cleanup;
+ }
+
+ cls->string =
+ ACPI_ADD_PTR(char, cls, sizeof(struct acpi_pnp_device_id));
+
+ sprintf(cls->string, "%02x%02x%02x",
+ (u8)ACPI_TO_INTEGER(cls_objects[0]->integer.value),
+ (u8)ACPI_TO_INTEGER(cls_objects[1]->integer.value),
+ (u8)ACPI_TO_INTEGER(cls_objects[2]->integer.value));
+ cls->length = 7;
+ *return_id = cls;
+ }
+
+cleanup:
+
+ /* On exit, we must delete the return object */
+
+ acpi_ut_remove_reference(obj_desc);
+ return_ACPI_STATUS(status);
+}
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index bbca783..f6ecbd1 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -907,10 +907,19 @@ static const struct acpi_device_id *__acpi_match_device(
if (!device->status.present)
return NULL;

- for (id = ids; id->id[0]; id++)
- list_for_each_entry(hwid, &device->pnp.ids, list)
- if (!strcmp((char *) id->id, hwid->id))
+ for (id = ids; id->id[0] || id->cls; id++) {
+ list_for_each_entry(hwid, &device->pnp.ids, list) {
+ if (id->id[0] && !strcmp((char *) id->id, hwid->id)) {
return id;
+ } else if (id->cls) {
+ char buf[7];
+
+ sprintf(buf, "%06x", id->cls);
+ if (!strcmp(buf, hwid->id))
+ return id;
+ }
+ }
+ }

return NULL;
}
@@ -1974,6 +1983,8 @@ static void acpi_set_pnp_ids(acpi_handle handle, struct acpi_device_pnp *pnp,
if (info->valid & ACPI_VALID_UID)
pnp->unique_id = kstrdup(info->unique_id.string,
GFP_KERNEL);
+ if (info->valid & ACPI_VALID_CLS)
+ acpi_add_id(pnp, info->cls.string);

kfree(info);

diff --git a/include/acpi/acnames.h b/include/acpi/acnames.h
index 273de70..b52c0dc 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/acpi/actypes.h b/include/acpi/actypes.h
index b034f10..ab3dac8 100644
--- a/include/acpi/actypes.h
+++ b/include/acpi/actypes.h
@@ -1148,7 +1148,7 @@ struct acpi_device_info {
u32 name; /* ACPI object Name */
acpi_object_type type; /* ACPI object Type */
u8 param_count; /* If a method, required parameter count */
- u8 valid; /* Indicates which optional fields are valid */
+ u16 valid; /* Indicates which optional fields are valid */
u8 flags; /* Miscellaneous info */
u8 highest_dstates[4]; /* _sx_d values: 0xFF indicates not valid */
u8 lowest_dstates[5]; /* _sx_w values: 0xFF indicates not valid */
@@ -1157,6 +1157,7 @@ struct acpi_device_info {
struct acpi_pnp_device_id hardware_id; /* _HID value */
struct acpi_pnp_device_id unique_id; /* _UID value */
struct acpi_pnp_device_id subsystem_id; /* _SUB value */
+ struct acpi_pnp_device_id cls; /* _CLS value */
struct acpi_pnp_device_id_list compatible_id_list; /* _CID list <must be last> */
};

@@ -1174,6 +1175,7 @@ struct acpi_device_info {
#define ACPI_VALID_CID 0x20
#define ACPI_VALID_SXDS 0x40
#define ACPI_VALID_SXWS 0x80
+#define ACPI_VALID_CLS 0x100

/* Flags for _STA return value (current_status above) */

diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index e530533..9a42522 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -189,6 +189,7 @@ struct css_device_id {
struct acpi_device_id {
__u8 id[ACPI_ID_LEN];
kernel_ulong_t driver_data;
+ __u32 cls;
};

#define PNP_ID_LEN 8
diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c
index f282516..7f68268 100644
--- a/scripts/mod/devicetable-offsets.c
+++ b/scripts/mod/devicetable-offsets.c
@@ -63,6 +63,7 @@ int main(void)

DEVID(acpi_device_id);
DEVID_FIELD(acpi_device_id, id);
+ DEVID_FIELD(acpi_device_id, cls);

DEVID(pnp_device_id);
DEVID_FIELD(pnp_device_id, id);
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index e614ef6..ba5998c 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -511,12 +511,21 @@ static int do_serio_entry(const char *filename,
}
ADD_TO_DEVTABLE("serio", serio_device_id, do_serio_entry);

-/* looks like: "acpi:ACPI0003 or acpi:PNP0C0B" or "acpi:LNXVIDEO" */
+/* looks like: "acpi:ACPI0003" or "acpi:PNP0C0B" or "acpi:LNXVIDEO" or
+ * "acpi:bbsspp" (bb=base-class, ss=sub-class, pp=prog-if)
+ *
+ * NOTE: * Each driver should use one of the following : _HID, _CIDs or _CLS.
+ */
static int do_acpi_entry(const char *filename,
void *symval, char *alias)
{
DEF_FIELD_ADDR(symval, acpi_device_id, id);
- sprintf(alias, "acpi*:%s:*", *id);
+ DEF_FIELD_ADDR(symval, acpi_device_id, cls);
+
+ if (id && strlen((const char *)*id))
+ sprintf(alias, "acpi*:%s:*", *id);
+ else if (cls)
+ sprintf(alias, "acpi*:%06x:*", *cls);
return 1;
}
ADD_TO_DEVTABLE("acpi", acpi_device_id, do_acpi_entry);
--
2.1.0