From 26095a01d359827eeccec5459c28ddd976183179 Mon Sep 17 00:00:00 2001 From: "Suthikulpanit, Suravee" Date: Tue, 7 Jul 2015 01:55:20 +0200 Subject: 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::::..::: 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 Reviewed-by: Hanjun Guo Signed-off-by: Suravee Suthikulpanit Signed-off-by: Rafael J. Wysocki --- drivers/acpi/scan.c | 32 ++++++++++++++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-) (limited to 'drivers/acpi/scan.c') diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 2649a068671d..ec256352f423 100644 --- 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); -- cgit v1.2.3