ACPI / scan: Add support for ACPI _CLS device matching

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@linux.intel.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 2649a06..ec25635 100644 (file)
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1019,6 +1019,29 @@ 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,
@@ -1036,9 +1059,12 @@ 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 ACPI_DT_NAMESPACE_HID and try to match the
@@ -2101,6 +2127,8 @@ 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->class_code.string);
 
                kfree(info);
 

diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index c471dfc..bdfdb9f 100644 (file)
--- 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);
@@ -446,6 +459,7 @@ 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 8183d66..34f25b7 100644 (file)
--- 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 eff7de1..e70fcd1 100644 (file)
--- 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 84c86f3..5f20882 100644 (file)
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -523,12 +523,40 @@ 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);