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X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 01 Apr 2024 07:50:52.4455 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 6a448785-3522-44c9-105c-08dc5220747c X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.160];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: BN1PEPF00004682.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA1PR12MB7409 Add support for preserving the boot configuration done by the platform firmware per host bridge basis, based on the presence of 'linux,pci-probe-only' property in the respective PCI host bridge device-tree node. It also unifies the ACPI and DT based boot flows in this regard. Signed-off-by: Vidya Sagar Reviewed-by: Rob Herring --- V5: * Addressed Rob's review comments V4: * Addressed Bjorn's review comments V3: * Unified ACPI and DT flows as part of addressing Bjorn's review comments V2: * Addressed issues reported by kernel test robot drivers/acpi/pci_root.c | 12 ----- drivers/pci/controller/pci-host-common.c | 4 -- drivers/pci/of.c | 57 +++++++++++++++++++----- drivers/pci/probe.c | 46 ++++++++++++++----- include/linux/of_pci.h | 6 +++ 5 files changed, 88 insertions(+), 37 deletions(-) diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c index 84030804a763..ddc2b3e89111 100644 --- a/drivers/acpi/pci_root.c +++ b/drivers/acpi/pci_root.c @@ -1008,7 +1008,6 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root, int node = acpi_get_node(device->handle); struct pci_bus *bus; struct pci_host_bridge *host_bridge; - union acpi_object *obj; info->root = root; info->bridge = device; @@ -1050,17 +1049,6 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root, if (!(root->osc_ext_control_set & OSC_CXL_ERROR_REPORTING_CONTROL)) host_bridge->native_cxl_error = 0; - /* - * Evaluate the "PCI Boot Configuration" _DSM Function. If it - * exists and returns 0, we must preserve any PCI resource - * assignments made by firmware for this host bridge. - */ - obj = acpi_evaluate_dsm(ACPI_HANDLE(bus->bridge), &pci_acpi_dsm_guid, 1, - DSM_PCI_PRESERVE_BOOT_CONFIG, NULL); - if (obj && obj->type == ACPI_TYPE_INTEGER && obj->integer.value == 0) - host_bridge->preserve_config = 1; - ACPI_FREE(obj); - acpi_dev_power_up_children_with_adr(device); pci_scan_child_bus(bus); diff --git a/drivers/pci/controller/pci-host-common.c b/drivers/pci/controller/pci-host-common.c index 6be3266cd7b5..e2602e38ae45 100644 --- a/drivers/pci/controller/pci-host-common.c +++ b/drivers/pci/controller/pci-host-common.c @@ -73,10 +73,6 @@ int pci_host_common_probe(struct platform_device *pdev) if (IS_ERR(cfg)) return PTR_ERR(cfg); - /* Do not reassign resources if probe only */ - if (!pci_has_flag(PCI_PROBE_ONLY)) - pci_add_flags(PCI_REASSIGN_ALL_BUS); - bridge->sysdata = cfg; bridge->ops = (struct pci_ops *)&ops->pci_ops; bridge->msi_domain = true; diff --git a/drivers/pci/of.c b/drivers/pci/of.c index 51e3dd0ea5ab..e6da3654f9ac 100644 --- a/drivers/pci/of.c +++ b/drivers/pci/of.c @@ -239,24 +239,61 @@ EXPORT_SYMBOL_GPL(of_get_pci_domain_nr); */ void of_pci_check_probe_only(void) { - u32 val; + bool is_preserve_config = of_pci_bridge_preserve_resources(of_chosen); + + if (is_preserve_config) + pci_add_flags(PCI_PROBE_ONLY); + else + pci_clear_flags(PCI_PROBE_ONLY); + + pr_info("PROBE_ONLY %s\n", is_preserve_config ? "enabled" : "disabled"); +} +EXPORT_SYMBOL_GPL(of_pci_check_probe_only); + +/** + * of_pci_bridge_preserve_resources - Return true if the boot configuration + * needs to be preserved + * @node: Device tree node. + * + * This function looks for "linux,pci-probe-only" property for a given + * PCI controller's node and returns true if found. It will also look in the + * chosen node if the property is not found in the given controller's node. + * Having this property ensures that the kernel doesn't reconfigure the + * BARs and bridge windows that are already done by the platform firmware. + * + * Return: true if the property exists false otherwise. + */ +bool of_pci_bridge_preserve_resources(struct device_node *node) +{ + u32 val = 0; int ret; - ret = of_property_read_u32(of_chosen, "linux,pci-probe-only", &val); + if (!node) { + pr_warn("device node is NULL, trying with of_chosen\n"); + node = of_chosen; + } + +retry: + ret = of_property_read_u32(node, "linux,pci-probe-only", &val); if (ret) { - if (ret == -ENODATA || ret == -EOVERFLOW) - pr_warn("linux,pci-probe-only without valid value, ignoring\n"); - return; + if (ret == -ENODATA || ret == -EOVERFLOW) { + pr_warn("Incorrect value for linux,pci-probe-only in %pOF, ignoring\n", node); + return false; + } + if (ret == -EINVAL) { + if (node == of_chosen) + return false; + + node = of_chosen; + goto retry; + } } if (val) - pci_add_flags(PCI_PROBE_ONLY); + return true; else - pci_clear_flags(PCI_PROBE_ONLY); - - pr_info("PROBE_ONLY %s\n", val ? "enabled" : "disabled"); + return false; } -EXPORT_SYMBOL_GPL(of_pci_check_probe_only); /** * devm_of_pci_get_host_bridge_resources() - Resource-managed parsing of PCI diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 795534589b98..b0e0226a8da8 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include @@ -877,6 +878,28 @@ static void pci_set_bus_msi_domain(struct pci_bus *bus) dev_set_msi_domain(&bus->dev, d); } +static void pci_check_config_preserve(struct pci_host_bridge *host_bridge) +{ + if (ACPI_HANDLE(&host_bridge->dev)) { + union acpi_object *obj; + + /* + * Evaluate the "PCI Boot Configuration" _DSM Function. If it + * exists and returns 0, we must preserve any PCI resource + * assignments made by firmware for this host bridge. + */ + obj = acpi_evaluate_dsm(ACPI_HANDLE(&host_bridge->dev), &pci_acpi_dsm_guid, 1, + DSM_PCI_PRESERVE_BOOT_CONFIG, NULL); + if (obj && obj->type == ACPI_TYPE_INTEGER && obj->integer.value == 0) + host_bridge->preserve_config = 1; + ACPI_FREE(obj); + } + + if (host_bridge->dev.parent && host_bridge->dev.parent->of_node) + host_bridge->preserve_config = + of_pci_bridge_preserve_resources(host_bridge->dev.parent->of_node); +} + static int pci_register_host_bridge(struct pci_host_bridge *bridge) { struct device *parent = bridge->dev.parent; @@ -971,6 +994,9 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge) if (nr_node_ids > 1 && pcibus_to_node(bus) == NUMA_NO_NODE) dev_warn(&bus->dev, "Unknown NUMA node; performance will be reduced\n"); + /* Check if the boot configuration by FW needs to be preserved */ + pci_check_config_preserve(bridge); + /* Coalesce contiguous windows */ resource_list_for_each_entry_safe(window, n, &resources) { if (list_is_last(&window->node, &resources)) @@ -3080,20 +3106,18 @@ int pci_host_probe(struct pci_host_bridge *bridge) bus = bridge->bus; + /* If we must preserve the resource configuration, claim now */ + if (bridge->preserve_config) + pci_bus_claim_resources(bus); + /* - * We insert PCI resources into the iomem_resource and - * ioport_resource trees in either pci_bus_claim_resources() - * or pci_bus_assign_resources(). + * Assign whatever was left unassigned. If we didn't claim above, + * this will reassign everything. */ - if (pci_has_flag(PCI_PROBE_ONLY)) { - pci_bus_claim_resources(bus); - } else { - pci_bus_size_bridges(bus); - pci_bus_assign_resources(bus); + pci_assign_unassigned_root_bus_resources(bus); - list_for_each_entry(child, &bus->children, node) - pcie_bus_configure_settings(child); - } + list_for_each_entry(child, &bus->children, node) + pcie_bus_configure_settings(child); pci_bus_add_devices(bus); return 0; diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h index 29658c0ee71f..3f3909a5d55d 100644 --- a/include/linux/of_pci.h +++ b/include/linux/of_pci.h @@ -13,6 +13,7 @@ struct device_node *of_pci_find_child_device(struct device_node *parent, unsigned int devfn); int of_pci_get_devfn(struct device_node *np); void of_pci_check_probe_only(void); +bool of_pci_bridge_preserve_resources(struct device_node *node); #else static inline struct device_node *of_pci_find_child_device(struct device_node *parent, unsigned int devfn) @@ -26,6 +27,11 @@ static inline int of_pci_get_devfn(struct device_node *np) } static inline void of_pci_check_probe_only(void) { } + +static inline bool of_pci_bridge_preserve_resources(struct device_node *node) +{ + return false; +} #endif #if IS_ENABLED(CONFIG_OF_IRQ)