diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 43075be79388ad5c8b1deae8011044680d50800e..ff1e720609529aa7d01ad1ad1ddff38ca4ccd849 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5208,6 +5208,28 @@ enum pcie_link_width pcie_get_width_cap(struct pci_dev *dev) return PCIE_LNK_WIDTH_UNKNOWN; } +/** + * pcie_bandwidth_capable - calculate a PCI device's link bandwidth capability + * @dev: PCI device + * @speed: storage for link speed + * @width: storage for link width + * + * Calculate a PCI device's link bandwidth by querying for its link speed + * and width, multiplying them, and applying encoding overhead. The result + * is in Mb/s, i.e., megabits/second of raw bandwidth. + */ +u32 pcie_bandwidth_capable(struct pci_dev *dev, enum pci_bus_speed *speed, + enum pcie_link_width *width) +{ + *speed = pcie_get_speed_cap(dev); + *width = pcie_get_width_cap(dev); + + if (*speed == PCI_SPEED_UNKNOWN || *width == PCIE_LNK_WIDTH_UNKNOWN) + return 0; + + return *width * PCIE_SPEED2MBS_ENC(*speed); +} + /** * pci_select_bars - Make BAR mask from the type of resource * @dev: the PCI device for which BAR mask is made diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 66738f1050c06bf6441ebc2e5ee7591c9d089063..ce9adec6c66e500f4bccb6a51d742a79f26d22ee 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -261,8 +261,18 @@ void pci_disable_bridge_window(struct pci_dev *dev); (speed) == PCIE_SPEED_2_5GT ? "2.5 GT/s" : \ "Unknown speed") +/* PCIe speed to Mb/s reduced by encoding overhead */ +#define PCIE_SPEED2MBS_ENC(speed) \ + ((speed) == PCIE_SPEED_16_0GT ? 16000*128/130 : \ + (speed) == PCIE_SPEED_8_0GT ? 8000*128/130 : \ + (speed) == PCIE_SPEED_5_0GT ? 5000*8/10 : \ + (speed) == PCIE_SPEED_2_5GT ? 2500*8/10 : \ + 0) + enum pci_bus_speed pcie_get_speed_cap(struct pci_dev *dev); enum pcie_link_width pcie_get_width_cap(struct pci_dev *dev); +u32 pcie_bandwidth_capable(struct pci_dev *dev, enum pci_bus_speed *speed, + enum pcie_link_width *width); /* Single Root I/O Virtualization */ struct pci_sriov {