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Subject[PATCH part1 v5 3/7] PCI: Add support for Device Serial Number capability
Date
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@cn.fujitsu.com>
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Paul Bolle <pebolle@tiscali.nl>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Oliver Neukum <oneukum@suse.de>
Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
---
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 432ac86..af06064 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2168,6 +2168,36 @@ 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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