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    Subject[PATCH v9 10/12] OF: PCI: Add support for creating a generic host_bridge from DT
    Date
    Provide a function to parse the PCI DT ranges and use it to
    create a pci_host_bridge structure together with its associated
    bus. Scan all the child busses and add the devices found.

    This is the OF equivalent of pci_scan_root_bus() where all the
    resources needed for creating the root bus are discovered from
    information passed in the device tree.

    Cc: Bjorn Helgaas <bhelgaas@google.com>
    Cc: Arnd Bergmann <arnd@arndb.de>
    Cc: Grant Likely <grant.likely@linaro.org>
    Cc: Rob Herring <robh+dt@kernel.org>
    Cc: Tanmay Inamdar <tinamdar@apm.com>
    Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
    ---
    drivers/of/of_pci.c | 159 ++++++++++++++++++++++++++++++++++++++++++++++
    drivers/pci/host-bridge.c | 15 +++++
    include/linux/of_pci.h | 13 ++++
    include/linux/pci.h | 6 ++
    4 files changed, 193 insertions(+)

    diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
    index a107edb..895b59f 100644
    --- a/drivers/of/of_pci.c
    +++ b/drivers/of/of_pci.c
    @@ -1,7 +1,9 @@
    #include <linux/kernel.h>
    #include <linux/export.h>
    #include <linux/of.h>
    +#include <linux/of_address.h>
    #include <linux/of_pci.h>
    +#include <linux/slab.h>

    static inline int __of_pci_pci_compare(struct device_node *node,
    unsigned int data)
    @@ -123,6 +125,163 @@ int of_pci_get_domain_nr(struct device_node *node, bool allocate_if_missing)
    }
    EXPORT_SYMBOL_GPL(of_pci_get_domain_nr);

    +/**
    + * pci_host_bridge_of_get_ranges - Parse PCI host bridge resources from DT
    + * @dev: device node of the host bridge having the range property
    + * @resources: list where the range of resources will be added after DT parsing
    + * @io_base: pointer to a variable that will contain on return the physical
    + * address for the start of the I/O range.
    + *
    + * It is the callers job to free the @resources list if an error is returned.
    + *
    + * This function will parse the "ranges" property of a PCI host bridge device
    + * node and setup the resource mapping based on its content. It is expected
    + * that the property conforms with the Power ePAPR document.
    + *
    + * Each architecture is then offered the chance of applying their own
    + * filtering of pci_host_bridge_windows based on their own restrictions by
    + * calling pcibios_fixup_bridge_ranges(). The filtered list of windows
    + * can then be used when creating a pci_host_bridge structure.
    + */
    +static int pci_host_bridge_of_get_ranges(struct device_node *dev,
    + struct list_head *resources, resource_size_t *io_base)
    +{
    + struct resource *res;
    + struct of_pci_range range;
    + struct of_pci_range_parser parser;
    + int err;
    +
    + pr_info("PCI host bridge %s ranges:\n", dev->full_name);
    +
    + /* Check for ranges property */
    + err = of_pci_range_parser_init(&parser, dev);
    + if (err)
    + return err;
    +
    + pr_debug("Parsing ranges property...\n");
    + for_each_of_pci_range(&parser, &range) {
    + /* Read next ranges element */
    + pr_info(" %s %#010llx..%#010llx -> %#010llx\n",
    + ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_IO) ? " IO" : "MEM",
    + range.cpu_addr, range.cpu_addr + range.size - 1,
    + range.pci_addr);
    +
    + /*
    + * If we failed translation or got a zero-sized region
    + * then skip this range
    + */
    + if (range.cpu_addr == OF_BAD_ADDR || range.size == 0)
    + continue;
    +
    + res = kzalloc(sizeof(struct resource), GFP_KERNEL);
    + if (!res)
    + return -ENOMEM;
    +
    + err = of_pci_range_to_resource(&range, dev, res);
    + if (err) {
    + kfree(res);
    + return err;
    + }
    +
    + if (resource_type(res) == IORESOURCE_IO) {
    + if (*io_base)
    + pr_warn("More than one I/O resource converted. CPU offset for old range lost!\n");
    + *io_base = range.cpu_addr;
    + }
    +
    + pci_add_resource_offset(resources, res,
    + res->start - range.pci_addr);
    + }
    +
    + /* Apply architecture specific fixups for the ranges */
    + return pcibios_fixup_bridge_ranges(resources);
    +}
    +
    +/**
    + * of_create_pci_host_bridge - Create a PCI host bridge structure using
    + * information passed in the DT.
    + * @parent: device owning this host bridge
    + * @busno: bus number associated with the bridge root bus.
    + * @bus_max: maximum number of busses for this bridge.
    + * @ops: pci_ops associated with the host controller
    + * @setup: setup function used by host controller driver to prepare the bridge.
    + * @host_data: opaque data structure used by the host controller.
    + *
    + * Returns zero if successful or a negative error value if the call failed.
    + */
    +int of_create_pci_host_bridge(struct device *parent, unsigned char busno,
    + unsigned char bus_max, struct pci_ops *ops,
    + int (*setup)(struct pci_host_bridge *, resource_size_t),
    + void *host_data)
    +{
    + int err, max;
    + struct resource *bus_range;
    + struct pci_bus *root_bus;
    + struct pci_host_bridge *bridge = NULL;
    + resource_size_t io_base = 0; /* physical address for the start of I/O area */
    + LIST_HEAD(res);
    +
    + bus_range = kzalloc(sizeof(*bus_range), GFP_KERNEL);
    + if (!bus_range)
    + return -ENOMEM;
    +
    + err = of_pci_parse_bus_range(parent->of_node, bus_range);
    + if (err) {
    + bus_range->start = busno;
    + bus_range->end = bus_max;
    + bus_range->flags = IORESOURCE_BUS;
    + dev_info(parent, "No bus range found for %s, using %pR\n",
    + parent->of_node->full_name, &bus_range);
    + } else {
    + if (bus_range->end > bus_range->start + bus_max)
    + bus_range->end = bus_range->start + bus_max;
    + }
    + pci_add_resource(&res, bus_range);
    +
    + /* now parse the rest of host bridge bus ranges */
    + err = pci_host_bridge_of_get_ranges(parent->of_node, &res, &io_base);
    + if (err)
    + goto err_create;
    +
    + /* then create the root bus */
    + root_bus = pci_create_root_bus(parent, busno, ops, host_data, &res);
    + if (!root_bus) {
    + err = -ENXIO;
    + goto err_create;
    + }
    +
    + bridge = to_pci_host_bridge(root_bus->bridge);
    +
    + /* give control to the host controller driver to finish setup */
    + if (setup) {
    + err = setup(bridge, io_base);
    + if (err)
    + goto err_setup;
    + }
    +
    + max = pci_scan_child_bus(root_bus);
    + pci_bus_update_busn_res_end(root_bus, max);
    +
    + if (!pci_has_flag(PCI_PROBE_ONLY))
    + pci_assign_unassigned_bus_resources(root_bus);
    +
    + pci_bus_add_devices(root_bus);
    +
    + return 0;
    +
    +err_setup:
    + pci_remove_bus(root_bus);
    + put_device(&bridge->dev);
    + device_unregister(&bridge->dev);
    + kfree(root_bus);
    + kfree(bridge);
    +
    +err_create:
    + pci_free_resource_list(&res);
    + return err;
    +}
    +EXPORT_SYMBOL_GPL(of_create_pci_host_bridge);
    +
    #ifdef CONFIG_PCI_MSI

    static LIST_HEAD(of_pci_msi_chip_list);
    diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
    index 0e5f3c9..3b22f93 100644
    --- a/drivers/pci/host-bridge.c
    +++ b/drivers/pci/host-bridge.c
    @@ -82,3 +82,18 @@ void pcibios_bus_to_resource(struct pci_bus *bus, struct resource *res,
    res->end = region->end + offset;
    }
    EXPORT_SYMBOL(pcibios_bus_to_resource);
    +
    +/**
    + * Simple version of the platform specific code for filtering the list
    + * of resources obtained from the ranges declaration in DT.
    + *
    + * Platforms can override this function in order to impose stronger
    + * constraints onto the list of resources that a host bridge can use.
    + * The filtered list will then be used to create a root bus and associate
    + * it with the host bridge.
    + *
    + */
    +int __weak pcibios_fixup_bridge_ranges(struct list_head *resources)
    +{
    + return 0;
    +}
    diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h
    index 3a3824c..f58a1cb 100644
    --- a/include/linux/of_pci.h
    +++ b/include/linux/of_pci.h
    @@ -16,6 +16,11 @@ int of_pci_get_devfn(struct device_node *np);
    int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin);
    int of_pci_parse_bus_range(struct device_node *node, struct resource *res);
    int of_pci_get_domain_nr(struct device_node *node, bool allocate_if_missing);
    +int of_create_pci_host_bridge(struct device *parent, unsigned char busno,
    + unsigned char bus_max, struct pci_ops *ops,
    + int (*setup)(struct pci_host_bridge *, resource_size_t),
    + void *host_data);
    +
    #else
    static inline int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq)
    {
    @@ -50,6 +55,14 @@ of_pci_get_domain_nr(struct device_node *node, bool allocate_if_missing)
    {
    return -1;
    }
    +
    +int of_create_pci_host_bridge(struct device *parent, unsigned char busno,
    + unsigned char bus_max, struct pci_ops *ops,
    + int (*setup)(struct pci_host_bridge *, resource_size_t),
    + void *host_data)
    +{
    + return -EINVAL;
    +}
    #endif

    #if defined(CONFIG_OF) && defined(CONFIG_PCI_MSI)
    diff --git a/include/linux/pci.h b/include/linux/pci.h
    index 1d0e0b5..e1e0d80 100644
    --- a/include/linux/pci.h
    +++ b/include/linux/pci.h
    @@ -1821,6 +1821,12 @@ static inline struct device_node *pci_bus_to_OF_node(struct pci_bus *bus)
    return bus ? bus->dev.of_node : NULL;
    }

    +/*
    + * Used by architecture code to apply any quirks to the list of
    + * pci_host_bridge resource ranges before they are being used
    + * by of_create_pci_host_bridge()
    + */
    +int pcibios_fixup_bridge_ranges(struct list_head *resources);
    #else /* CONFIG_OF */
    static inline void pci_set_of_node(struct pci_dev *dev) { }
    static inline void pci_release_of_node(struct pci_dev *dev) { }
    --
    2.0.4


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