diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 91138cbeb8537e01148664cee0bd8b0d7cfb130c..e7a3917ed38969671f9f1536cf1a1ef537b277d6 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5288,6 +5288,38 @@ u32 pcie_bandwidth_capable(struct pci_dev *dev, enum pci_bus_speed *speed, return *width * PCIE_SPEED2MBS_ENC(*speed); } +/** + * pcie_print_link_status - Report the PCI device's link speed and width + * @dev: PCI device to query + * + * Report the available bandwidth at the device. If this is less than the + * device is capable of, report the device's maximum possible bandwidth and + * the upstream link that limits its performance to less than that. + */ +void pcie_print_link_status(struct pci_dev *dev) +{ + enum pcie_link_width width, width_cap; + enum pci_bus_speed speed, speed_cap; + struct pci_dev *limiting_dev = NULL; + u32 bw_avail, bw_cap; + + bw_cap = pcie_bandwidth_capable(dev, &speed_cap, &width_cap); + bw_avail = pcie_bandwidth_available(dev, &limiting_dev, &speed, &width); + + if (bw_avail >= bw_cap) + pci_info(dev, "%u.%03u Gb/s available bandwidth (%s x%d link)\n", + bw_cap / 1000, bw_cap % 1000, + PCIE_SPEED2STR(speed_cap), width_cap); + else + pci_info(dev, "%u.%03u Gb/s available bandwidth, limited by %s x%d link at %s (capable of %u.%03u Gb/s with %s x%d link)\n", + bw_avail / 1000, bw_avail % 1000, + PCIE_SPEED2STR(speed), width, + limiting_dev ? pci_name(limiting_dev) : "", + bw_cap / 1000, bw_cap % 1000, + PCIE_SPEED2STR(speed_cap), width_cap); +} +EXPORT_SYMBOL(pcie_print_link_status); + /** * pci_select_bars - Make BAR mask from the type of resource * @dev: the PCI device for which BAR mask is made diff --git a/include/linux/pci.h b/include/linux/pci.h index f2bf2b7a66c77a61708577775c3b1c54860e7727..38f7957121ef736ba8d5bed750e2278738352e10 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1086,6 +1086,7 @@ int pcie_get_minimum_link(struct pci_dev *dev, enum pci_bus_speed *speed, u32 pcie_bandwidth_available(struct pci_dev *dev, struct pci_dev **limiting_dev, enum pci_bus_speed *speed, enum pcie_link_width *width); +void pcie_print_link_status(struct pci_dev *dev); void pcie_flr(struct pci_dev *dev); int __pci_reset_function_locked(struct pci_dev *dev); int pci_reset_function(struct pci_dev *dev);