From 79c731e20d7401cc39e4f0e633b135b966a04f62 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ilpo=20J=C3=A4rvinen?= Date: Fri, 7 Feb 2025 18:18:35 +0200 Subject: [PATCH] PCI: Track Flit Mode Status & print it with link status MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit PCIe r6.0 added Flit mode, which mainly alters HW behavior, but there are some OS visible changes. The OS visible changes include differences in the layout of some capabilities and interpretation of the TLP headers (in diagnostics situations). To be able to determine which mode the PCIe Link is using, store the Flit Mode Status (PCIe r6.1 sec 7.5.3.20) information in addition to the Link speed into struct pci_bus in pcie_update_link_speed(). Link: https://lore.kernel.org/r/20250207161836.2755-2-ilpo.jarvinen@linux.intel.com Signed-off-by: Ilpo Järvinen [bhelgaas: use unsigned int:1 instead of bool, update flit_mode setting] Signed-off-by: Bjorn Helgaas --- drivers/pci/hotplug/pciehp_hpc.c | 5 +++-- drivers/pci/pci.c | 12 ++++++++---- drivers/pci/pci.h | 3 ++- drivers/pci/probe.c | 5 +++-- include/linux/pci.h | 1 + 5 files changed, 17 insertions(+), 9 deletions(-) diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index bb5a8d9f03ad..10130ac9f979 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -292,7 +292,7 @@ int pciehp_check_link_status(struct controller *ctrl) { struct pci_dev *pdev = ctrl_dev(ctrl); bool found; - u16 lnk_status; + u16 lnk_status, linksta2; if (!pcie_wait_for_link(pdev, true)) { ctrl_info(ctrl, "Slot(%s): No link\n", slot_name(ctrl)); @@ -319,7 +319,8 @@ int pciehp_check_link_status(struct controller *ctrl) return -1; } - __pcie_update_link_speed(ctrl->pcie->port->subordinate, lnk_status); + pcie_capability_read_word(pdev, PCI_EXP_LNKSTA2, &linksta2); + __pcie_update_link_speed(ctrl->pcie->port->subordinate, lnk_status, linksta2); if (!found) { ctrl_info(ctrl, "Slot(%s): No device found\n", diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 869d204a70a3..313c66863752 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -6190,21 +6190,25 @@ void __pcie_print_link_status(struct pci_dev *dev, bool verbose) enum pci_bus_speed speed, speed_cap; struct pci_dev *limiting_dev = NULL; u32 bw_avail, bw_cap; + char *flit_mode = ""; bw_cap = pcie_bandwidth_capable(dev, &speed_cap, &width_cap); bw_avail = pcie_bandwidth_available(dev, &limiting_dev, &speed, &width); + if (dev->bus && dev->bus->flit_mode) + flit_mode = ", in Flit mode"; + if (bw_avail >= bw_cap && verbose) - pci_info(dev, "%u.%03u Gb/s available PCIe bandwidth (%s x%d link)\n", + pci_info(dev, "%u.%03u Gb/s available PCIe bandwidth (%s x%d link)%s\n", bw_cap / 1000, bw_cap % 1000, - pci_speed_string(speed_cap), width_cap); + pci_speed_string(speed_cap), width_cap, flit_mode); else if (bw_avail < bw_cap) - pci_info(dev, "%u.%03u Gb/s available PCIe bandwidth, limited by %s x%d link at %s (capable of %u.%03u Gb/s with %s x%d link)\n", + pci_info(dev, "%u.%03u Gb/s available PCIe bandwidth, limited by %s x%d link at %s (capable of %u.%03u Gb/s with %s x%d link)%s\n", bw_avail / 1000, bw_avail % 1000, pci_speed_string(speed), width, limiting_dev ? pci_name(limiting_dev) : "", bw_cap / 1000, bw_cap % 1000, - pci_speed_string(speed_cap), width_cap); + pci_speed_string(speed_cap), width_cap, flit_mode); } /** diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 01e51db8d285..9da7da58e0de 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -406,9 +406,10 @@ const char *pci_speed_string(enum pci_bus_speed speed); void __pcie_print_link_status(struct pci_dev *dev, bool verbose); void pcie_report_downtraining(struct pci_dev *dev); -static inline void __pcie_update_link_speed(struct pci_bus *bus, u16 linksta) +static inline void __pcie_update_link_speed(struct pci_bus *bus, u16 linksta, u16 linksta2) { bus->cur_bus_speed = pcie_link_speed[linksta & PCI_EXP_LNKSTA_CLS]; + bus->flit_mode = (linksta2 & PCI_EXP_LNKSTA2_FLIT) ? 1 : 0; } void pcie_update_link_speed(struct pci_bus *bus); diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index b6536ed599c3..e6f11498a345 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -788,10 +788,11 @@ EXPORT_SYMBOL_GPL(pci_speed_string); void pcie_update_link_speed(struct pci_bus *bus) { struct pci_dev *bridge = bus->self; - u16 linksta; + u16 linksta, linksta2; pcie_capability_read_word(bridge, PCI_EXP_LNKSTA, &linksta); - __pcie_update_link_speed(bus, linksta); + pcie_capability_read_word(bridge, PCI_EXP_LNKSTA2, &linksta2); + __pcie_update_link_speed(bus, linksta, linksta2); } EXPORT_SYMBOL_GPL(pcie_update_link_speed); diff --git a/include/linux/pci.h b/include/linux/pci.h index 47b31ad724fa..e4bf67bf8172 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -681,6 +681,7 @@ struct pci_bus { struct bin_attribute *legacy_mem; /* Legacy mem */ unsigned int is_added:1; unsigned int unsafe_warn:1; /* warned about RW1C config write */ + unsigned int flit_mode:1; /* Link in Flit mode */ }; #define to_pci_bus(n) container_of(n, struct pci_bus, dev) -- 2.50.1