Commit 26095a01 authored by Suthikulpanit, Suravee's avatar Suthikulpanit, Suravee Committed by Rafael J. Wysocki
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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: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: default avatarHanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: default avatarSuravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent d770e558

drivers/acpi/scan.c

+30 −2
Original line number Diff line number Diff line
@@ -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);

include/linux/acpi.h

+14 −0
Original line number Diff line number Diff line
@@ -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;

include/linux/mod_devicetable.h

+2 −0
Original line number Diff line number Diff line
@@ -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

scripts/mod/devicetable-offsets.c

+2 −0
Original line number Diff line number Diff line
@@ -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);

scripts/mod/file2alias.c

+30 −2
Original line number Diff line number Diff line
@@ -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);

	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);

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