[PATCH] Add support for reading SMBIOS Slot number for PCI devices

[Jordan Hargrave]

From: Jordan Hargrave <Jordan_Hargrave@xxxxxxxx>

There currently isn't an easy way to determine which PCI devices belong to
system slots.  This patch adds support to read SMBIOS Type 9 (System Slots).

Signed-off-by: Jordan Hargrave <Jordan_Hargrave@xxxxxxxx>
---
 drivers/firmware/dmi_scan.c | 39 ++++++++++++++++++++
 drivers/pci/pci-label.c     | 89 +++++++++++++++++++++++++++++++++++++++++++++
 include/linux/dmi.h         |  1 +
 3 files changed, 129 insertions(+)

diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index ac1ce4a..8f95897 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -356,6 +356,41 @@ static void __init dmi_save_extended_devices(const struct dmi_header *dm)
 	dmi_save_one_device(*d & 0x7f, dmi_string_nosave(dm, *(d - 1)));
 }
 
+static void __init dmi_save_dev_slot(int instance, int segment, int bus, int devfn, const char *name)
+{
+	struct dmi_dev_onboard *slot;
+	
+	slot = dmi_alloc(sizeof(*slot) + strlen(name) + 1);
+	if (!slot) {
+		printk(KERN_ERR "dmi_save_system_slot: out of memory.\n");
+		return;
+	}
+	slot->instance = instance;
+	slot->segment = segment;
+	slot->bus = bus;
+	slot->devfn = devfn;
+
+	strcpy((char *)&slot[1], name);
+	slot->dev.type = DMI_DEV_TYPE_SYSTEM_SLOT;
+	slot->dev.name = (char *)&slot[1];
+	slot->dev.device_data = slot;
+
+	list_add(&slot->dev.list, &dmi_devices);
+}
+
+
+static void __init dmi_save_system_slot(const struct dmi_header *dm)
+{
+	const char *name;
+	const u8 *d = (u8*)dm;
+	
+	if (dm->type == DMI_ENTRY_SYSTEM_SLOT && dm->length >= 0x11) {
+		name = dmi_string_nosave(dm, *(d + 0x04));
+		dmi_save_dev_slot(*(u16 *)(d + 0x09), *(u16 *)(d + 0xD), 
+				  *(d + 0xF), *(d + 0x10), name);
+	}
+}
+
 static void __init count_mem_devices(const struct dmi_header *dm, void *v)
 {
 	if (dm->type != DMI_ENTRY_MEM_DEVICE)
@@ -437,6 +472,10 @@ static void __init dmi_decode(const struct dmi_header *dm, void *dummy)
 		break;
 	case 41:	/* Onboard Devices Extended Information */
 		dmi_save_extended_devices(dm);
+		break;
+	case 9:         /* System Slots */
+		dmi_save_system_slot(dm);
+		break;
 	}
 }
 
diff --git a/drivers/pci/pci-label.c b/drivers/pci/pci-label.c
index 024b5c1..38dfb45 100644
--- a/drivers/pci/pci-label.c
+++ b/drivers/pci/pci-label.c
@@ -125,14 +125,103 @@ static struct attribute_group smbios_attr_group = {
 	.is_visible = smbios_instance_string_exist,
 };
 
+static int smbios_getslot(struct pci_dev *pdev)
+{
+	struct pci_dev *sdev;
+	struct dmi_dev_onboard *dslot;
+	const struct dmi_device *dmi;
+	u8 sub, sec, bus;
+
+	dmi = NULL;
+	if (pdev->is_virtfn) {
+		/* Get Physical device for SR-IOV */
+		pdev = pdev->physfn;
+	}
+	bus = pdev->bus->number;
+	while ((dmi = dmi_find_device(DMI_DEV_TYPE_SYSTEM_SLOT, NULL, dmi)) != NULL) {
+		sec = sub = -1;
+
+		dslot = dmi->device_data;
+		sdev = pci_get_domain_bus_and_slot(dslot->segment, dslot->bus, dslot->devfn);
+		if (sdev == NULL)
+			continue;
+
+		if (sdev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
+			pci_read_config_byte(sdev, PCI_SECONDARY_BUS, &sec);
+			pci_read_config_byte(sdev, PCI_SUBORDINATE_BUS, &sub);
+			if (bus >= sec && bus <= sub) {
+				/* device is child of bridge */
+				return dslot->instance;
+			}
+		}
+		if (pci_domain_nr(sdev->bus) == pci_domain_nr(pdev->bus) &&
+		    sdev->bus->number == pdev->bus->number &&
+		    PCI_SLOT(sdev->devfn) == PCI_SLOT(pdev->devfn)) {
+			/* Match domain:bus:dev.  If PCIE root, only match function */
+			if (PCI_FUNC(sdev->devfn) == PCI_FUNC(pdev->devfn) ||
+			    pci_pcie_type(sdev) != PCI_EXP_TYPE_ROOT_PORT) {
+				return dslot->instance;
+			}
+		}
+	}
+	return -ENODEV;
+}
+ 
+static ssize_t smbiosslot_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+ 	struct pci_dev *pdev;
+	int slot;
+ 
+ 	pdev = to_pci_dev(dev);
+	slot = smbios_getslot(pdev);
+	if (slot > 0) {
+		return scnprintf(buf, PAGE_SIZE, "%d\n", slot);
+	}
+	return 0;
+}
+
+static umode_t smbios_slot_exist(struct kobject *kobj, struct attribute *attr,
+				 int n)
+{
+	struct device *dev;
+	struct pci_dev *pdev;
+
+	dev = container_of(kobj, struct device, kobj);
+	pdev = to_pci_dev(dev);
+
+	return (smbios_getslot(pdev) > 0) ? S_IRUGO : 0;
+}
+
+static struct device_attribute smbios_attr_slot = {
+	.attr = {.name = "slot", .mode = 0444},
+	.show = smbiosslot_show,
+};
+
+static struct attribute *smbios_slot_attributes[] = {
+	&smbios_attr_slot.attr,
+	NULL,
+};
+
+static struct attribute_group smbios_slot_attr_group = {
+	.attrs = smbios_slot_attributes,
+	.is_visible = smbios_slot_exist,
+};
+
 static int pci_create_smbiosname_file(struct pci_dev *pdev)
 {
+	int rc;
+
+	rc = sysfs_create_group(&pdev->dev.kobj, &smbios_slot_attr_group);
+	if (rc != 0)
+		return rc;
 	return sysfs_create_group(&pdev->dev.kobj, &smbios_attr_group);
 }
 
 static void pci_remove_smbiosname_file(struct pci_dev *pdev)
 {
 	sysfs_remove_group(&pdev->dev.kobj, &smbios_attr_group);
+	sysfs_remove_group(&pdev->dev.kobj, &smbios_slot_attr_group);
 }
 #else
 static inline int pci_create_smbiosname_file(struct pci_dev *pdev)
diff --git a/include/linux/dmi.h b/include/linux/dmi.h
index 5055ac3..09f42e7 100644
--- a/include/linux/dmi.h
+++ b/include/linux/dmi.h
@@ -22,6 +22,7 @@ enum dmi_device_type {
 	DMI_DEV_TYPE_IPMI = -1,
 	DMI_DEV_TYPE_OEM_STRING = -2,
 	DMI_DEV_TYPE_DEV_ONBOARD = -3,
+	DMI_DEV_TYPE_SYSTEM_SLOT = -4,
 };
 
 enum dmi_entry_type {
-- 
1.8.3.1

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