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ACPI / scan: Add support for ACPI _CLS device matching

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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 <[email protected]>
Reviewed-by: Hanjun Guo <[email protected]>
Signed-off-by: Suravee Suthikulpanit <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
This commit is contained in:
Suthikulpanit, Suravee 2015-07-07 01:55:20 +02:00 • committed by Rafael J. Wysocki
commit 26095a01d3
5 changed files with 78 additions and 4 deletions
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32
drivers/acpi/scan.c
View file

@ -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);