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[] = {
{ ACPI_DEVICE_CLASS(PCI_CLASS_STORAGE_SATA_AHCI, 0xffffff) },
{},
};
In this case, the corresponded entry in modules.alias file would be:
alias acpi*:010601:* ahci_platform
Acked-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Reviewed-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
---
drivers/acpi/scan.c | 32 ++++++++++++++++++++++++++++++--
include/linux/acpi.h | 14 ++++++++++++++
include/linux/mod_devicetable.h | 2 ++
scripts/mod/devicetable-offsets.c | 2 ++
scripts/mod/file2alias.c | 32 ++++++++++++++++++++++++++++++--
5 files changed, 78 insertions(+), 4 deletions(-)
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 79a48bb..f0662aa 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1017,6 +1017,29 @@ static bool acpi_of_match_device(struct acpi_device *adev,
return false;
}
+static bool __acpi_match_device_cls(const struct acpi_device_id *id,
+ struct acpi_hardware_id *hwid)
+{
+ int i, msk, byte_shift;
+ char buf[3];
+
+ if (!id->cls)
+ return false;
+
+ /* Apply class-code bitmask, before checking each class-code byte */
+ for (i = 1; i <= 3; i++) {
+ byte_shift = 8 * (3 - i);
+ msk = (id->cls_msk >> byte_shift) & 0xFF;
+ if (!msk)
+ continue;
+
+ sprintf(buf, "%02x", (id->cls >> byte_shift) & msk);
+ if (strncmp(buf, &hwid->id[(i - 1) * 2], 2))
+ return false;
+ }
+ return true;
+}
+
static const struct acpi_device_id *__acpi_match_device(
struct acpi_device *device,
const struct acpi_device_id *ids,
@@ -1034,9 +1057,12 @@ static const struct acpi_device_id *__acpi_match_device(
list_for_each_entry(hwid, &device->pnp.ids, list) {
/* First, check the ACPI/PNP IDs provided by the caller. */
- for (id = ids; id->id[0]; id++)
- if (!strcmp((char *) id->id, hwid->id))
+ for (id = ids; id->id[0] || id->cls; id++) {
+ if (id->id[0] && !strcmp((char *) id->id, hwid->id))
return id;
+ else if (id->cls && __acpi_match_device_cls(id, hwid))
+ return id;
+ }
/*
* Next, check the special "PRP0001" ID and try to match the
@@ -2057,6 +2083,8 @@ 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/linux/acpi.h b/include/linux/acpi.h
index e4da5e3..b10c4a6 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -58,6 +58,19 @@ static inline acpi_handle acpi_device_handle(struct acpi_device *adev)
acpi_fwnode_handle(adev) : NULL)
#define ACPI_HANDLE(dev) acpi_device_handle(ACPI_COMPANION(dev))
+/**
+ * ACPI_DEVICE_CLASS - macro used to describe an ACPI device with
+ * the PCI-defined class-code information
+ *
+ * @_cls : the class, subclass, prog-if triple for this device
+ * @_msk : the class mask for this device
+ *
+ * This macro is used to create a struct acpi_device_id that matches a
+ * specific PCI class. The .id and .driver_data fields will be left
+ * initialized with the default value.
+ */
+#define ACPI_DEVICE_CLASS(_cls, _msk) .cls = (_cls), .cls_msk = (_msk),
+
static inline bool has_acpi_companion(struct device *dev)
{
return is_acpi_node(dev->fwnode);
@@ -465,6 +478,7 @@ struct platform_device *acpi_create_platform_device(struct acpi_device *);
#define ACPI_COMPANION(dev) (NULL)
#define ACPI_COMPANION_SET(dev, adev) do { } while (0)
#define ACPI_HANDLE(dev) (NULL)
+#define ACPI_DEVICE_CLASS(_cls, _msk) .cls = (0), .cls_msk = (0),
struct fwnode_handle;
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 3bfd567..242037b 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -189,6 +189,8 @@ struct css_device_id {
struct acpi_device_id {
__u8 id[ACPI_ID_LEN];
kernel_ulong_t driver_data;
+ __u32 cls;
+ __u32 cls_msk;
};
#define PNP_ID_LEN 8
diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c
index fce36d0..0ced0ca 100644
--- a/scripts/mod/devicetable-offsets.c
+++ b/scripts/mod/devicetable-offsets.c
@@ -63,6 +63,8 @@ int main(void)
DEVID(acpi_device_id);
DEVID_FIELD(acpi_device_id, id);
+ DEVID_FIELD(acpi_device_id, cls);
+ DEVID_FIELD(acpi_device_id, cls_msk);
DEVID(pnp_device_id);
DEVID_FIELD(pnp_device_id, id);
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index 78691d5..ea238e2f 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -511,12 +511,40 @@ 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. Also, bb, ss, and pp can be substituted with ??
+ * as don't care byte.
+ */
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);
+ DEF_FIELD_ADDR(symval, acpi_device_id, cls_msk);
+
+ if (id && strlen((const char *)*id))
+ sprintf(alias, "acpi*:%s:*", *id);
+ else if (cls) {
+ int i, byte_shift, cnt = 0;
+ unsigned int msk;
+
+ sprintf(&alias[cnt], "acpi*:");
+ cnt = 6;
+ for (i = 1; i <= 3; i++) {
+ byte_shift = 8 * (3-i);
+ msk = (*cls_msk >> byte_shift) & 0xFF;
+ if (msk)
+ sprintf(&alias[cnt], "%02x",
+ (*cls >> byte_shift) & 0xFF);
+ else
+ sprintf(&alias[cnt], "??");
+ cnt += 2;
+ }
+ sprintf(&alias[cnt], ":*");
+ }
return 1;
}
ADD_TO_DEVTABLE("acpi", acpi_device_id, do_acpi_entry);
--
2.1.0
--
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