From 3b62449da444502d8b87bf090d8ec4a57d47eda5 Mon Sep 17 00:00:00 2001 From: Herve Codina Date: Mon, 24 Feb 2025 15:13:51 +0100 Subject: [PATCH 1/5] driver core: Introduce device_{add,remove}_of_node() An of_node can be set to a device using device_set_node(), which does not prevent any of_node and/or fwnode overwrites. When adding an of_node on an already present device, the following operations need to be done: - Attach the of_node only if no of_node is already attached - Attach the of_node as a fwnode if no fwnode were already attached This is the purpose of device_add_of_node(). device_remove_of_node() reverts the operations done by device_add_of_node(). Link: https://lore.kernel.org/r/20250224141356.36325-2-herve.codina@bootlin.com Signed-off-by: Herve Codina Signed-off-by: Bjorn Helgaas Reviewed-by: Rob Herring (Arm) Acked-by: Greg Kroah-Hartman --- drivers/base/core.c | 61 ++++++++++++++++++++++++++++++++++++++++++ include/linux/device.h | 2 ++ 2 files changed, 63 insertions(+) diff --git a/drivers/base/core.c b/drivers/base/core.c index 5a1f05198114..49eb5aaf19cc 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -5170,6 +5170,67 @@ void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode) } EXPORT_SYMBOL_GPL(set_secondary_fwnode); +/** + * device_remove_of_node - Remove an of_node from a device + * @dev: device whose device tree node is being removed + */ +void device_remove_of_node(struct device *dev) +{ + dev = get_device(dev); + if (!dev) + return; + + if (!dev->of_node) + goto end; + + if (dev->fwnode == of_fwnode_handle(dev->of_node)) + dev->fwnode = NULL; + + of_node_put(dev->of_node); + dev->of_node = NULL; + +end: + put_device(dev); +} +EXPORT_SYMBOL_GPL(device_remove_of_node); + +/** + * device_add_of_node - Add an of_node to an existing device + * @dev: device whose device tree node is being added + * @of_node: of_node to add + * + * Return: 0 on success or error code on failure. + */ +int device_add_of_node(struct device *dev, struct device_node *of_node) +{ + int ret; + + if (!of_node) + return -EINVAL; + + dev = get_device(dev); + if (!dev) + return -EINVAL; + + if (dev->of_node) { + dev_err(dev, "Cannot replace node %pOF with %pOF\n", + dev->of_node, of_node); + ret = -EBUSY; + goto end; + } + + dev->of_node = of_node_get(of_node); + + if (!dev->fwnode) + dev->fwnode = of_fwnode_handle(of_node); + + ret = 0; +end: + put_device(dev); + return ret; +} +EXPORT_SYMBOL_GPL(device_add_of_node); + /** * device_set_of_node_from_dev - reuse device-tree node of another device * @dev: device whose device-tree node is being set diff --git a/include/linux/device.h b/include/linux/device.h index 80a5b3268986..1244e5892292 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -1191,6 +1191,8 @@ int device_online(struct device *dev); void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode); void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode); void device_set_node(struct device *dev, struct fwnode_handle *fwnode); +int device_add_of_node(struct device *dev, struct device_node *of_node); +void device_remove_of_node(struct device *dev); void device_set_of_node_from_dev(struct device *dev, const struct device *dev2); static inline struct device_node *dev_of_node(struct device *dev) From e2267841fe26d45d3c95958ddb71905a4cd4ac92 Mon Sep 17 00:00:00 2001 From: Herve Codina Date: Mon, 24 Feb 2025 15:13:52 +0100 Subject: [PATCH 2/5] PCI: of: Use device_{add,remove}_of_node() to attach of_node to existing device The commit 407d1a51921e ("PCI: Create device tree node for bridge") creates of_node for PCI devices. The newly created of_node is attached to an existing device. This is done setting directly pdev->dev.of_node in the code. Even if pdev->dev.of_node cannot be previously set, this doesn't handle the fwnode field of the struct device. Indeed, this field needs to be set if it hasn't already been set. device_{add,remove}_of_node() have been introduced to handle this case. Use them instead of the direct setting. Link: https://lore.kernel.org/r/20250224141356.36325-3-herve.codina@bootlin.com Signed-off-by: Herve Codina Signed-off-by: Bjorn Helgaas Reviewed-by: Rob Herring (Arm) --- drivers/pci/of.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/pci/of.c b/drivers/pci/of.c index 7a806f5c0d20..fb5e6da1ead0 100644 --- a/drivers/pci/of.c +++ b/drivers/pci/of.c @@ -653,8 +653,8 @@ void of_pci_remove_node(struct pci_dev *pdev) np = pci_device_to_OF_node(pdev); if (!np || !of_node_check_flag(np, OF_DYNAMIC)) return; - pdev->dev.of_node = NULL; + device_remove_of_node(&pdev->dev); of_changeset_revert(np->data); of_changeset_destroy(np->data); of_node_put(np); @@ -711,11 +711,18 @@ void of_pci_make_dev_node(struct pci_dev *pdev) goto out_free_node; np->data = cset; - pdev->dev.of_node = np; + + ret = device_add_of_node(&pdev->dev, np); + if (ret) + goto out_revert_cset; + kfree(name); return; +out_revert_cset: + np->data = NULL; + of_changeset_revert(cset); out_free_node: of_node_put(np); out_destroy_cset: From c5785a165f847c457bd398f496f7c108527b22bd Mon Sep 17 00:00:00 2001 From: Herve Codina Date: Mon, 24 Feb 2025 15:13:53 +0100 Subject: [PATCH 3/5] PCI: of_property: Add support for NULL pdev in of_pci_set_address() The pdev (pointer to a struct pci_dev) parameter of of_pci_set_address() cannot be NULL. In order to use of_pci_set_address() when creating the PCI root bus node, it needs to support a NULL pdev parameter. Indeed, in the case of the PCI root bus node creation, no pdev is available and of_pci_set_address() will be used with the bridge windows. Allow to call of_pci_set_address() with a NULL pdev. Link: https://lore.kernel.org/r/20250224141356.36325-4-herve.codina@bootlin.com Signed-off-by: Herve Codina Signed-off-by: Bjorn Helgaas Reviewed-by: Rob Herring (Arm) --- drivers/pci/of_property.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/pci/of_property.c b/drivers/pci/of_property.c index 58fbafac7c6a..a6acd64ff869 100644 --- a/drivers/pci/of_property.c +++ b/drivers/pci/of_property.c @@ -54,9 +54,13 @@ enum of_pci_prop_compatible { static void of_pci_set_address(struct pci_dev *pdev, u32 *prop, u64 addr, u32 reg_num, u32 flags, bool reloc) { - prop[0] = FIELD_PREP(OF_PCI_ADDR_FIELD_BUS, pdev->bus->number) | - FIELD_PREP(OF_PCI_ADDR_FIELD_DEV, PCI_SLOT(pdev->devfn)) | - FIELD_PREP(OF_PCI_ADDR_FIELD_FUNC, PCI_FUNC(pdev->devfn)); + if (pdev) { + prop[0] = FIELD_PREP(OF_PCI_ADDR_FIELD_BUS, pdev->bus->number) | + FIELD_PREP(OF_PCI_ADDR_FIELD_DEV, PCI_SLOT(pdev->devfn)) | + FIELD_PREP(OF_PCI_ADDR_FIELD_FUNC, PCI_FUNC(pdev->devfn)); + } else + prop[0] = 0; + prop[0] |= flags | reg_num; if (!reloc) { prop[0] |= OF_PCI_ADDR_FIELD_NONRELOC; From 3dc8adeeefa0256917d1e3978c8b4a06346816ed Mon Sep 17 00:00:00 2001 From: Herve Codina Date: Mon, 24 Feb 2025 15:13:54 +0100 Subject: [PATCH 4/5] PCI: of_property: Constify parameter in of_pci_get_addr_flags() The res parameter has no reason to be a pointer to an un-const struct resource. Indeed, struct resource is not supposed to be modified by the function. Constify the res parameter. Link: https://lore.kernel.org/r/20250224141356.36325-5-herve.codina@bootlin.com Signed-off-by: Herve Codina Signed-off-by: Bjorn Helgaas Reviewed-by: Rob Herring (Arm) --- drivers/pci/of_property.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/pci/of_property.c b/drivers/pci/of_property.c index a6acd64ff869..afc229843d07 100644 --- a/drivers/pci/of_property.c +++ b/drivers/pci/of_property.c @@ -69,7 +69,7 @@ static void of_pci_set_address(struct pci_dev *pdev, u32 *prop, u64 addr, } } -static int of_pci_get_addr_flags(struct resource *res, u32 *flags) +static int of_pci_get_addr_flags(const struct resource *res, u32 *flags) { u32 ss; From 1f340724419eda8ab07a20edcaf5ec8f70134231 Mon Sep 17 00:00:00 2001 From: Herve Codina Date: Mon, 24 Feb 2025 15:13:55 +0100 Subject: [PATCH 5/5] PCI: of: Create device tree PCI host bridge node PCI devices device tree nodes can be already created. This was introduced by commit 407d1a51921e ("PCI: Create device tree node for bridge"). In order to have device tree nodes related to PCI devices attached on their PCI root bus (the PCI bus handled by the PCI host bridge), a PCI root bus device tree node is needed. This root bus node will be used as the parent node of the first level devices scanned on the bus. On device tree based systems, this PCI root bus device tree node is set to the node of the related PCI host bridge. The PCI host bridge node is available in the device tree used to describe the hardware passed at boot. On non device tree based system (such as ACPI), a device tree node for the PCI host bridge or for the root bus does not exist. Indeed, the PCI host bridge is not described in a device tree used at boot simply because no device tree is passed at boot. The device tree PCI host bridge node creation needs to be done at runtime. This is done in the same way as for the creation of the PCI device nodes. I.e. node and properties are created based on computed information done by the PCI core. Also, as is done on device tree based systems, this PCI host bridge node is used for the PCI root bus. With this done, hardware available in a PCI device that doesn't follow the PCI model consisting in one PCI function handled by one driver can be described by a device tree overlay loaded by the PCI device driver on non device tree based systems. Those PCI devices provide a single PCI function that includes several functionalities that require different drivers. The device tree overlay describes the internal devices and their relationships. It allows to load drivers needed by those different devices in order to have functionalities handled. Link: https://lore.kernel.org/r/20250224141356.36325-6-herve.codina@bootlin.com Signed-off-by: Herve Codina Signed-off-by: Bjorn Helgaas Reviewed-by: Rob Herring (Arm) --- drivers/pci/of.c | 107 +++++++++++++++++++++++++++++++++++++- drivers/pci/of_property.c | 103 ++++++++++++++++++++++++++++++++++++ drivers/pci/pci.h | 7 +++ drivers/pci/probe.c | 2 + drivers/pci/remove.c | 2 + 5 files changed, 220 insertions(+), 1 deletion(-) diff --git a/drivers/pci/of.c b/drivers/pci/of.c index fb5e6da1ead0..762d4e3fde3c 100644 --- a/drivers/pci/of.c +++ b/drivers/pci/of.c @@ -731,7 +731,112 @@ void of_pci_make_dev_node(struct pci_dev *pdev) out_free_name: kfree(name); } -#endif + +void of_pci_remove_host_bridge_node(struct pci_host_bridge *bridge) +{ + struct device_node *np; + + np = pci_bus_to_OF_node(bridge->bus); + if (!np || !of_node_check_flag(np, OF_DYNAMIC)) + return; + + device_remove_of_node(&bridge->bus->dev); + device_remove_of_node(&bridge->dev); + of_changeset_revert(np->data); + of_changeset_destroy(np->data); + of_node_put(np); +} + +void of_pci_make_host_bridge_node(struct pci_host_bridge *bridge) +{ + struct device_node *np = NULL; + struct of_changeset *cset; + const char *name; + int ret; + + /* + * If there is already a device tree node linked to the PCI bus handled + * by this bridge (i.e. the PCI root bus), nothing to do. + */ + if (pci_bus_to_OF_node(bridge->bus)) + return; + + /* + * The root bus has no node. Check that the host bridge has no node + * too + */ + if (bridge->dev.of_node) { + dev_err(&bridge->dev, "PCI host bridge of_node already set"); + return; + } + + /* Check if there is a DT root node to attach the created node */ + if (!of_root) { + pr_err("of_root node is NULL, cannot create PCI host bridge node\n"); + return; + } + + name = kasprintf(GFP_KERNEL, "pci@%x,%x", pci_domain_nr(bridge->bus), + bridge->bus->number); + if (!name) + return; + + cset = kmalloc(sizeof(*cset), GFP_KERNEL); + if (!cset) + goto out_free_name; + of_changeset_init(cset); + + np = of_changeset_create_node(cset, of_root, name); + if (!np) + goto out_destroy_cset; + + ret = of_pci_add_host_bridge_properties(bridge, cset, np); + if (ret) + goto out_free_node; + + /* + * This of_node will be added to an existing device. The of_node parent + * is the root OF node and so this node will be handled by the platform + * bus. Avoid any new device creation. + */ + of_node_set_flag(np, OF_POPULATED); + np->fwnode.dev = &bridge->dev; + fwnode_dev_initialized(&np->fwnode, true); + + ret = of_changeset_apply(cset); + if (ret) + goto out_free_node; + + np->data = cset; + + /* Add the of_node to host bridge and the root bus */ + ret = device_add_of_node(&bridge->dev, np); + if (ret) + goto out_revert_cset; + + ret = device_add_of_node(&bridge->bus->dev, np); + if (ret) + goto out_remove_bridge_dev_of_node; + + kfree(name); + + return; + +out_remove_bridge_dev_of_node: + device_remove_of_node(&bridge->dev); +out_revert_cset: + np->data = NULL; + of_changeset_revert(cset); +out_free_node: + of_node_put(np); +out_destroy_cset: + of_changeset_destroy(cset); + kfree(cset); +out_free_name: + kfree(name); +} + +#endif /* CONFIG_PCI_DYNAMIC_OF_NODES */ /** * of_pci_supply_present() - Check if the power supply is present for the PCI diff --git a/drivers/pci/of_property.c b/drivers/pci/of_property.c index afc229843d07..506fcd507113 100644 --- a/drivers/pci/of_property.c +++ b/drivers/pci/of_property.c @@ -394,3 +394,106 @@ int of_pci_add_properties(struct pci_dev *pdev, struct of_changeset *ocs, return 0; } + +static bool of_pci_is_range_resource(const struct resource *res, u32 *flags) +{ + if (!(resource_type(res) & IORESOURCE_MEM) && + !(resource_type(res) & IORESOURCE_MEM_64)) + return false; + + if (of_pci_get_addr_flags(res, flags)) + return false; + + return true; +} + +static int of_pci_host_bridge_prop_ranges(struct pci_host_bridge *bridge, + struct of_changeset *ocs, + struct device_node *np) +{ + struct resource_entry *window; + unsigned int ranges_sz = 0; + unsigned int n_range = 0; + struct resource *res; + int n_addr_cells; + u32 *ranges; + u64 val64; + u32 flags; + int ret; + + n_addr_cells = of_n_addr_cells(np); + if (n_addr_cells <= 0 || n_addr_cells > 2) + return -EINVAL; + + resource_list_for_each_entry(window, &bridge->windows) { + res = window->res; + if (!of_pci_is_range_resource(res, &flags)) + continue; + n_range++; + } + + if (!n_range) + return 0; + + ranges = kcalloc(n_range, + (OF_PCI_ADDRESS_CELLS + OF_PCI_SIZE_CELLS + + n_addr_cells) * sizeof(*ranges), + GFP_KERNEL); + if (!ranges) + return -ENOMEM; + + resource_list_for_each_entry(window, &bridge->windows) { + res = window->res; + if (!of_pci_is_range_resource(res, &flags)) + continue; + + /* PCI bus address */ + val64 = res->start; + of_pci_set_address(NULL, &ranges[ranges_sz], + val64 - window->offset, 0, flags, false); + ranges_sz += OF_PCI_ADDRESS_CELLS; + + /* Host bus address */ + if (n_addr_cells == 2) + ranges[ranges_sz++] = upper_32_bits(val64); + ranges[ranges_sz++] = lower_32_bits(val64); + + /* Size */ + val64 = resource_size(res); + ranges[ranges_sz] = upper_32_bits(val64); + ranges[ranges_sz + 1] = lower_32_bits(val64); + ranges_sz += OF_PCI_SIZE_CELLS; + } + + ret = of_changeset_add_prop_u32_array(ocs, np, "ranges", ranges, + ranges_sz); + kfree(ranges); + return ret; +} + +int of_pci_add_host_bridge_properties(struct pci_host_bridge *bridge, + struct of_changeset *ocs, + struct device_node *np) +{ + int ret; + + ret = of_changeset_add_prop_string(ocs, np, "device_type", "pci"); + if (ret) + return ret; + + ret = of_changeset_add_prop_u32(ocs, np, "#address-cells", + OF_PCI_ADDRESS_CELLS); + if (ret) + return ret; + + ret = of_changeset_add_prop_u32(ocs, np, "#size-cells", + OF_PCI_SIZE_CELLS); + if (ret) + return ret; + + ret = of_pci_host_bridge_prop_ranges(bridge, ocs, np); + if (ret) + return ret; + + return 0; +} diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 01e51db8d285..889cdb1e6fcb 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -876,9 +876,16 @@ void of_pci_make_dev_node(struct pci_dev *pdev); void of_pci_remove_node(struct pci_dev *pdev); int of_pci_add_properties(struct pci_dev *pdev, struct of_changeset *ocs, struct device_node *np); +void of_pci_make_host_bridge_node(struct pci_host_bridge *bridge); +void of_pci_remove_host_bridge_node(struct pci_host_bridge *bridge); +int of_pci_add_host_bridge_properties(struct pci_host_bridge *bridge, + struct of_changeset *ocs, + struct device_node *np); #else static inline void of_pci_make_dev_node(struct pci_dev *pdev) { } static inline void of_pci_remove_node(struct pci_dev *pdev) { } +static inline void of_pci_make_host_bridge_node(struct pci_host_bridge *bridge) { } +static inline void of_pci_remove_host_bridge_node(struct pci_host_bridge *bridge) { } #endif #ifdef CONFIG_PCIEAER diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index b6536ed599c3..b74a12a0193a 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1094,6 +1094,8 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge) dev_info(&bus->dev, "root bus resource %pR%s\n", res, addr); } + of_pci_make_host_bridge_node(bridge); + down_write(&pci_bus_sem); list_add_tail(&bus->node, &pci_root_buses); up_write(&pci_bus_sem); diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c index efc37fcb73e2..9f7df2b20183 100644 --- a/drivers/pci/remove.c +++ b/drivers/pci/remove.c @@ -163,6 +163,8 @@ void pci_stop_root_bus(struct pci_bus *bus) &bus->devices, bus_list) pci_stop_bus_device(child); + of_pci_remove_host_bridge_node(host_bridge); + /* stop the host bridge */ device_release_driver(&host_bridge->dev); }