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, 241 insertions, 6 deletions

diff --git a/drivers/pci/pci-label.c b/drivers/pci/pci-label.c
index 90c0a729cd3a..824e247edc58 100644
--- a/drivers/pci/pci-label.c
+++ b/drivers/pci/pci-label.c
@@ -5,6 +5,13 @@
  * by Narendra K <Narendra_K@dell.com>,
  * Jordan Hargrave <Jordan_Hargrave@dell.com>
  *
+ * PCI Firmware Specification Revision 3.1 section 4.6.7 (DSM for Naming a
+ * PCI or PCI Express Device Under Operating Systems) defines an instance
+ * number and string name. This code retrieves them and exports them to sysfs.
+ * If the system firmware does not provide the ACPI _DSM (Device Specific
+ * Method), then the SMBIOS type 41 instance number and string is exported to
+ * sysfs.
+ *
  * SMBIOS defines type 41 for onboard pci devices. This code retrieves
  * the instance number and string from the type 41 record and exports
  * it to sysfs.
@@ -19,8 +26,30 @@
 #include <linux/pci_ids.h>
 #include <linux/module.h>
 #include <linux/device.h>
+#include <linux/nls.h>
+#include <linux/acpi.h>
+#include <linux/pci-acpi.h>
+#include <acpi/acpi_drivers.h>
+#include <acpi/acpi_bus.h>
 #include "pci.h"
 
+#define DEVICE_LABEL_DSM        0x07
+
+#ifndef CONFIG_DMI
+
+static inline int
+pci_create_smbiosname_file(struct pci_dev *pdev)
+{
+        return -1;
+}
+
+static inline void
+pci_remove_smbiosname_file(struct pci_dev *pdev)
+{
+}
+
+#else
+
 enum smbios_attr_enum {
         SMBIOS_ATTR_NONE = 0,
         SMBIOS_ATTR_LABEL_SHOW,
@@ -120,9 +149,7 @@ static struct attribute_group smbios_attr_group = {
 static int
 pci_create_smbiosname_file(struct pci_dev *pdev)
 {
-        if (!sysfs_create_group(&pdev->dev.kobj, &smbios_attr_group))
-                return 0;
-        return -ENODEV;
+        return sysfs_create_group(&pdev->dev.kobj, &smbios_attr_group);
 }
 
 static void
@@ -131,13 +158,221 @@ pci_remove_smbiosname_file(struct pci_dev *pdev)
         sysfs_remove_group(&pdev->dev.kobj, &smbios_attr_group);
 }
 
+#endif
+
+#ifndef CONFIG_ACPI
+
+static inline int
+pci_create_acpi_index_label_files(struct pci_dev *pdev)
+{
+        return -1;
+}
+
+static inline int
+pci_remove_acpi_index_label_files(struct pci_dev *pdev)
+{
+        return -1;
+}
+
+#else
+
+static const char device_label_dsm_uuid[] = {
+        0xD0, 0x37, 0xC9, 0xE5, 0x53, 0x35, 0x7A, 0x4D,
+        0x91, 0x17, 0xEA, 0x4D, 0x19, 0xC3, 0x43, 0x4D
+};
+
+enum acpi_attr_enum {
+        ACPI_ATTR_NONE = 0,
+        ACPI_ATTR_LABEL_SHOW,
+        ACPI_ATTR_INDEX_SHOW,
+};
+
+static void dsm_label_utf16s_to_utf8s(union acpi_object *obj, char *buf)
+{
+        int len;
+        len = utf16s_to_utf8s((const wchar_t *)obj->
+                              package.elements[1].string.pointer,
+                              obj->package.elements[1].string.length,
+                              UTF16_LITTLE_ENDIAN,
+                              buf, PAGE_SIZE);
+        buf[len] = '\n';
+}
+
+static int
+dsm_get_label(acpi_handle handle, int func,
+              struct acpi_buffer *output,
+              char *buf, enum acpi_attr_enum attribute)
+{
+        struct acpi_object_list input;
+        union acpi_object params[4];
+        union acpi_object *obj;
+        int len = 0;
+
+        int err;
+
+        input.count = 4;
+        input.pointer = params;
+        params[0].type = ACPI_TYPE_BUFFER;
+        params[0].buffer.length = sizeof(device_label_dsm_uuid);
+        params[0].buffer.pointer = (char *)device_label_dsm_uuid;
+        params[1].type = ACPI_TYPE_INTEGER;
+        params[1].integer.value = 0x02;
+        params[2].type = ACPI_TYPE_INTEGER;
+        params[2].integer.value = func;
+        params[3].type = ACPI_TYPE_PACKAGE;
+        params[3].package.count = 0;
+        params[3].package.elements = NULL;
+
+        err = acpi_evaluate_object(handle, "_DSM", &input, output);
+        if (err)
+                return -1;
+
+        obj = (union acpi_object *)output->pointer;
+
+        switch (obj->type) {
+        case ACPI_TYPE_PACKAGE:
+                if (obj->package.count != 2)
+                        break;
+                len = obj->package.elements[0].integer.value;
+                if (buf) {
+                        if (attribute == ACPI_ATTR_INDEX_SHOW)
+                                scnprintf(buf, PAGE_SIZE, "%llu\n",
+                                obj->package.elements[0].integer.value);
+                        else if (attribute == ACPI_ATTR_LABEL_SHOW)
+                                dsm_label_utf16s_to_utf8s(obj, buf);
+                        kfree(output->pointer);
+                        return strlen(buf);
+                }
+                kfree(output->pointer);
+                return len;
+        break;
+        default:
+                kfree(output->pointer);
+        }
+        return -1;
+}
+
+static bool
+device_has_dsm(struct device *dev)
+{
+        acpi_handle handle;
+        struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
+
+        handle = DEVICE_ACPI_HANDLE(dev);
+
+        if (!handle)
+                return FALSE;
+
+        if (dsm_get_label(handle, DEVICE_LABEL_DSM, &output, NULL,
+                          ACPI_ATTR_NONE) > 0)
+                return TRUE;
+
+        return FALSE;
+}
+
+static mode_t
+acpi_index_string_exist(struct kobject *kobj, struct attribute *attr, int n)
+{
+        struct device *dev;
+
+        dev = container_of(kobj, struct device, kobj);
+
+        if (device_has_dsm(dev))
+                return S_IRUGO;
+
+        return 0;
+}
+
+static ssize_t
+acpilabel_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+        struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
+        acpi_handle handle;
+        int length;
+
+        handle = DEVICE_ACPI_HANDLE(dev);
+
+        if (!handle)
+                return -1;
+
+        length = dsm_get_label(handle, DEVICE_LABEL_DSM,
+                               &output, buf, ACPI_ATTR_LABEL_SHOW);
+
+        if (length < 1)
+                return -1;
+
+        return length;
+}
+
+static ssize_t
+acpiindex_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+        struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
+        acpi_handle handle;
+        int length;
+
+        handle = DEVICE_ACPI_HANDLE(dev);
+
+        if (!handle)
+                return -1;
+
+        length = dsm_get_label(handle, DEVICE_LABEL_DSM,
+                               &output, buf, ACPI_ATTR_INDEX_SHOW);
+
+        if (length < 0)
+                return -1;
+
+        return length;
+
+}
+
+static struct device_attribute acpi_attr_label = {
+        .attr = {.name = "label", .mode = 0444},
+        .show = acpilabel_show,
+};
+
+static struct device_attribute acpi_attr_index = {
+        .attr = {.name = "acpi_index", .mode = 0444},
+        .show = acpiindex_show,
+};
+
+static struct attribute *acpi_attributes[] = {
+        &acpi_attr_label.attr,
+        &acpi_attr_index.attr,
+        NULL,
+};
+
+static struct attribute_group acpi_attr_group = {
+        .attrs = acpi_attributes,
+        .is_visible = acpi_index_string_exist,
+};
+
+static int
+pci_create_acpi_index_label_files(struct pci_dev *pdev)
+{
+        return sysfs_create_group(&pdev->dev.kobj, &acpi_attr_group);
+}
+
+static int
+pci_remove_acpi_index_label_files(struct pci_dev *pdev)
+{
+        sysfs_remove_group(&pdev->dev.kobj, &acpi_attr_group);
+        return 0;
+}
+#endif
+
 void pci_create_firmware_label_files(struct pci_dev *pdev)
 {
-        if (!pci_create_smbiosname_file(pdev))
-                ;
+        if (device_has_dsm(&pdev->dev))
+                pci_create_acpi_index_label_files(pdev);
+        else
+                pci_create_smbiosname_file(pdev);
 }
 
 void pci_remove_firmware_label_files(struct pci_dev *pdev)
 {
-        pci_remove_smbiosname_file(pdev);
+        if (device_has_dsm(&pdev->dev))
+                pci_remove_acpi_index_label_files(pdev);
+        else
+                pci_remove_smbiosname_file(pdev);
 }