[RFC PATCH v2 01/32] PCI: add pcie_flags_reg into struct pci_dev to cache PCIe capabilities register
From: Jiang Liu <hidden>
Date: 2012-07-24 16:33:32
Also in:
lkml
Subsystem:
pci subsystem, the rest · Maintainers:
Bjorn Helgaas, Linus Torvalds
From: Yijing Wang <redacted> From: Yijing Wang <redacted> 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 <redacted> Signed-off-by: Jiang Liu <redacted> --- drivers/pci/probe.c | 1 + include/linux/pci.h | 10 ++++++++++ 2 files changed, 11 insertions(+)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 6c143b4..6fd58df 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c@@ -929,6 +929,7 @@ void set_pcie_port_type(struct pci_dev *pdev) pdev->is_pcie = 1; pdev->pcie_cap = pos; pci_read_config_word(pdev, pos + PCI_EXP_FLAGS, ®16); + pdev->pcie_flags_reg = reg16; pdev->pcie_type = (reg16 & PCI_EXP_FLAGS_TYPE) >> 4; pci_read_config_word(pdev, pos + PCI_EXP_DEVCAP, ®16); pdev->pcie_mpss = reg16 & PCI_EXP_DEVCAP_PAYLOAD;
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 @@ struct pci_dev { 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 @@ static inline bool pci_is_pcie(struct pci_dev *dev) 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,
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1.7.9.5