Add support for the Device Serial Number capability, so we can use the
unique device serial number to identify the physical device. This helps
determine whether a device was replaced while the system was suspended.
[bhelgaas: changelog, drop pci_dsn_init(), spell out "serial_number"]
Reviewed-by: Gu Zheng <guz.fnst@xxxxxxxxxxxxxx>
Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Paul Bolle <pebolle@xxxxxxxxxx>
Cc: Oliver Neukum <oneukum@xxxxxxx>
Cc: Gu Zheng <guz.fnst@xxxxxxxxxxxxxx>
---
drivers/pci/pci.c | 30 ++++++++++++++++++++++++++++++
drivers/pci/pci.h | 2 +-
drivers/pci/probe.c | 2 ++
include/linux/pci.h | 1 +
4 files changed, 34 insertions(+), 1 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 4502e6f..a8c1c2d 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2169,6 +2169,36 @@ void pci_free_cap_save_buffers(struct pci_dev *dev)
}
/**
+ * pci_device_serial_number - get device serial number
+ * @bus: PCI bus the device on
+ * @devfn: the PCI device
+ *
+ * return the device serial number if device support,
+ * otherwise return 0.
+ */
+static u64 pci_device_serial_number(struct pci_bus *bus, int devfn)
+{
+ int pos;
+ u32 lo, hi;
+
+ if (!pci_bus_find_capability(bus, devfn, PCI_CAP_ID_EXP))
+ return 0;
+
+ pos = pci_bus_find_ext_capability(bus, devfn, PCI_EXT_CAP_ID_DSN);
+ if (!pos)
+ return 0;
+
+ pci_bus_read_config_dword(bus, devfn, pos + 4, &lo);
+ pci_bus_read_config_dword(bus, devfn, pos + 8, &hi);
+ return ((u64)hi << 32) | lo;
+}
+
+void pci_dsn_init(struct pci_dev *dev)
+{
+ dev->sn = pci_device_serial_number(dev->bus, dev->devfn);
+}
+
+/**
* pci_configure_ari - enable or disable ARI forwarding
* @dev: the PCI device
*
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 4df38df..685301a 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -208,7 +208,7 @@ void __ref __pci_bus_size_bridges(struct pci_bus *bus,
void __ref __pci_bus_assign_resources(const struct pci_bus *bus,
struct list_head *realloc_head,
struct list_head *fail_head);
-
+void pci_dsn_init(struct pci_dev *dev);
/**
* pci_ari_enabled - query ARI forwarding status
* @bus: the PCI bus
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 6e34498..27d3e6f 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1324,6 +1324,8 @@ static void pci_init_capabilities(struct pci_dev *dev)
/* Vital Product Data */
pci_vpd_pci22_init(dev);
+ pci_dsn_init(dev);
+
/* Alternative Routing-ID Forwarding */
pci_configure_ari(dev);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 470de02..3631859 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -354,6 +354,7 @@ struct pci_dev {
struct list_head msi_list;
const struct attribute_group **msi_irq_groups;
#endif
+ u64 sn; /* device serial number, 0 if not support */
struct pci_vpd *vpd;
#ifdef CONFIG_PCI_ATS
union {
--
1.7.1
--
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