PCI: Export ACPI _DSM provided firmware instance number and string name to sysfs

This patch exports ACPI _DSM (Device Specific Method) provided firmware
instance number and string name of PCI devices as defined by 'PCI
Firmware Specification Revision 3.1' section 4.6.7.( DSM for Naming a
PCI or PCI Express Device Under Operating Systems) to sysfs.

New files created are:
  /sys/bus/pci/devices/.../label which contains the firmware name for
the device in question, and
  /sys/bus/pci/devices/.../acpi_index which contains the firmware device type
instance for the given device.

cat /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0/acpi_index
1
cat /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0/label
Embedded Broadcom 5709C NIC 1

cat /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.1/acpi_index
2
cat /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.1/label
Embedded Broadcom 5709C NIC 2

The ACPI _DSM provided firmware 'instance number' and 'string name' will
be given priority if the firmware also provides 'SMBIOS type 41 device
type instance and string'.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Jordan Hargrave <jordan_hargrave@dell.com>
Signed-off-by: Narendra K <narendra_k@dell.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 24 insertions, 7 deletions

diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index f979d825d112..36bf454ba855 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -145,9 +145,11 @@ Date:		July 2010
 Contact:        Narendra K <narendra_k@dell.com>, linux-bugs@dell.com
 Description:
                 Reading this attribute will provide the firmware
-                given name(SMBIOS type 41 string) of the PCI device.
-                The attribute will be created only if the firmware
-                has given a name to the PCI device.
+                given name (SMBIOS type 41 string or ACPI _DSM string) of
+                the PCI device. The attribute will be created only
+                if the firmware has given a name to the PCI device.
+                ACPI _DSM string name will be given priority if the
+                system firmware provides SMBIOS type 41 string also.
 Users:
                 Userspace applications interested in knowing the
                 firmware assigned name of the PCI device.
@@ -157,12 +159,27 @@ Date:		July 2010
 Contact:        Narendra K <narendra_k@dell.com>, linux-bugs@dell.com
 Description:
                 Reading this attribute will provide the firmware
-                given instance(SMBIOS type 41 device type instance)
-                of the PCI device. The attribute will be created
-                only if the firmware has given a device type instance
-                to the PCI device.
+                given instance (SMBIOS type 41 device type instance) of the
+                PCI device. The attribute will be created only if the firmware
+                has given an instance number to the PCI device.
 Users:
                 Userspace applications interested in knowing the
                 firmware assigned device type instance of the PCI
                 device that can help in understanding the firmware
                 intended order of the PCI device.
+
+What:           /sys/bus/pci/devices/.../acpi_index
+Date:           July 2010
+Contact:        Narendra K <narendra_k@dell.com>, linux-bugs@dell.com
+Description:
+                Reading this attribute will provide the firmware
+                given instance (ACPI _DSM instance number) of the PCI device.
+                The attribute will be created only if the firmware has given
+                an instance number to the PCI device. ACPI _DSM instance number
+                will be given priority if the system firmware provides SMBIOS
+                type 41 device type instance also.
+Users:
+                Userspace applications interested in knowing the
+                firmware assigned instance number of the PCI
+                device that can help in understanding the firmware
+                intended order of the PCI device.