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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>
This commit is contained in:
Yijing Wang 2012-07-24 17:20:02 +08:00 committed by Jiang Liu
parent 0d7614f09c
commit 786e22885d
2 changed files with 12 additions and 1 deletions
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3
drivers/pci/probe.c
View File

@ -929,7 +929,8 @@ 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, &reg16);
pdev->pcie_type = (reg16 & PCI_EXP_FLAGS_TYPE) >> 4;
pdev->pcie_flags_reg = reg16;
pdev->pcie_type = pci_pcie_type(pdev);
pci_read_config_word(pdev, pos + PCI_EXP_DEVCAP, &reg16);
pdev->pcie_mpss = reg16 & PCI_EXP_DEVCAP_PAYLOAD;
}

10
include/linux/pci.h
View File

@ -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,