Add pci_find_vsec_capability() that crawls through the device config
space searching in all Vendor-Specific Extended Capabilities for a
particular capability ID.
Vendor-Specific Extended Capability (VSEC) is a PCIe capability (acts
like a wrapper) specified by PCI-SIG that allows the vendor to create
their own and specific capability in the device config space.
Signed-off-by: Gustavo Pimentel <gustavo.pimentel@xxxxxxxxxxxx>
---
drivers/pci/pci.c | 29 +++++++++++++++++++++++++++++
include/linux/pci.h | 1 +
include/uapi/linux/pci_regs.h | 5 +++++
3 files changed, 35 insertions(+)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 6d4d5a2..235d0b2 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -623,6 +623,35 @@ u64 pci_get_dsn(struct pci_dev *dev)
}
EXPORT_SYMBOL_GPL(pci_get_dsn);
+/**
+ * pci_find_vsec_capability - Find a vendor-specific extended capability
+ * @dev: PCI device to query
+ * @cap: vendor-specific capability id code
+ *
+ * Returns the address of the vendor-specific structure that matches the
+ * requested capability id code within the device's PCI configuration space
+ * or 0 if it does not find a match.
+ */
+int pci_find_vsec_capability(struct pci_dev *dev, int vsec_cap_id)
+{
+ u32 header;
+ int vsec;
+
+ vsec = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_VNDR);
+ while (vsec) {
+ if (pci_read_config_dword(dev, vsec + 0x4,
+ &header) == PCIBIOS_SUCCESSFUL &&
+ PCI_VSEC_CAP_ID(header) == vsec_cap_id)
+ break;
+
+ vsec = pci_find_next_ext_capability(dev, vsec,
+ PCI_EXT_CAP_ID_VNDR);
+ }
+
+ return vsec;
+}
+EXPORT_SYMBOL_GPL(pci_find_vsec_capability);
+
static int __pci_find_next_ht_cap(struct pci_dev *dev, int pos, int ht_cap)
{
int rc, ttl = PCI_FIND_CAP_TTL;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 22207a7..effecb0 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1067,6 +1067,7 @@ int pci_find_capability(struct pci_dev *dev, int cap);
int pci_find_next_capability(struct pci_dev *dev, u8 pos, int cap);
int pci_find_ext_capability(struct pci_dev *dev, int cap);
int pci_find_next_ext_capability(struct pci_dev *dev, int pos, int cap);
+int pci_find_vsec_capability(struct pci_dev *dev, int vsec_cap_id);
int pci_find_ht_capability(struct pci_dev *dev, int ht_cap);
int pci_find_next_ht_capability(struct pci_dev *dev, int pos, int ht_cap);
struct pci_bus *pci_find_next_bus(const struct pci_bus *from);
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index a95d55f..f5d17be 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -730,6 +730,11 @@
#define PCI_EXT_CAP_DSN_SIZEOF 12
#define PCI_EXT_CAP_MCAST_ENDPOINT_SIZEOF 40
+/* Vendor-Specific Extended Capabilities */
+#define PCI_VSEC_CAP_ID(header) (header & 0x0000ffff)
+#define PCI_VSEC_CAP_REV(header) ((header >> 16) & 0xf)
+#define PCI_VSEC_CAP_LEN(header) ((header >> 20) & 0xffc)
+
/* Advanced Error Reporting */
#define PCI_ERR_UNCOR_STATUS 4 /* Uncorrectable Error Status */
#define PCI_ERR_UNC_UND 0x00000001 /* Undefined */
--
2.7.4
