PCI: Add pcie_flags_reg to cache PCIe capabilities register
Since PCI Express Capabilities Register is read only, cache its value
into struct pci_dev to avoid repeatedly calling pci_read_config_*().
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 5faa831..95662b2 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -258,6 +258,7 @@
u8 pcie_mpss:3; /* PCI-E Max Payload Size Supported */
u8 rom_base_reg; /* which config register controls the ROM */
u8 pin; /* which interrupt pin this device uses */
+ u16 pcie_flags_reg; /* cached PCI-E Capabilities Register */
struct pci_driver *driver; /* which driver has allocated this device */
u64 dma_mask; /* Mask of the bits of bus address this
@@ -1650,6 +1651,15 @@
return !!pci_pcie_cap(dev);
}
+/**
+ * pci_pcie_type - get the PCIe device/port type
+ * @dev: PCI device
+ */
+static inline int pci_pcie_type(const struct pci_dev *dev)
+{
+ return (dev->pcie_flags_reg & PCI_EXP_FLAGS_TYPE) >> 4;
+}
+
void pci_request_acs(void);
bool pci_acs_enabled(struct pci_dev *pdev, u16 acs_flags);
bool pci_acs_path_enabled(struct pci_dev *start,