// SPDX-License-Identifier: GPL-2.0+
/*
 * PCI <-> OF mapping helpers
 *
 * Copyright 2011 IBM Corp.
 */
#define pr_fmt(fmt)     "PCI: OF: " fmt

#include <linux/irqdomain.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/of_address.h>
#include <linux/of_pci.h>
#include "pci.h"

void pci_set_of_node(struct pci_dev *dev)
{
        if (!dev->bus->dev.of_node)
                return;
        dev->dev.of_node = of_pci_find_child_device(dev->bus->dev.of_node,
                                                    dev->devfn);
}

void pci_release_of_node(struct pci_dev *dev)
{
        of_node_put(dev->dev.of_node);
        dev->dev.of_node = NULL;
}

void pci_set_bus_of_node(struct pci_bus *bus)
{
        struct device_node *node;

        if (bus->self == NULL) {
                node = pcibios_get_phb_of_node(bus);
        } else {
                node = of_node_get(bus->self->dev.of_node);
                if (node && of_property_read_bool(node, "external-facing"))
                        bus->self->external_facing = true;
        }
        bus->dev.of_node = node;
}

void pci_release_bus_of_node(struct pci_bus *bus)
{
        of_node_put(bus->dev.of_node);
        bus->dev.of_node = NULL;
}

struct device_node * __weak pcibios_get_phb_of_node(struct pci_bus *bus)
{
        /* This should only be called for PHBs */
        if (WARN_ON(bus->self || bus->parent))
                return NULL;

        /*
         * Look for a node pointer in either the intermediary device we
         * create above the root bus or its own parent. Normally only
         * the later is populated.
         */
        if (bus->bridge->of_node)
                return of_node_get(bus->bridge->of_node);
        if (bus->bridge->parent && bus->bridge->parent->of_node)
                return of_node_get(bus->bridge->parent->of_node);
        return NULL;
}

struct irq_domain *pci_host_bridge_of_msi_domain(struct pci_bus *bus)
{
#ifdef CONFIG_IRQ_DOMAIN
        struct irq_domain *d;

        if (!bus->dev.of_node)
                return NULL;

        /* Start looking for a phandle to an MSI controller. */
        d = of_msi_get_domain(&bus->dev, bus->dev.of_node, DOMAIN_BUS_PCI_MSI);
        if (d)
                return d;

        /*
         * If we don't have an msi-parent property, look for a domain
         * directly attached to the host bridge.
         */
        d = irq_find_matching_host(bus->dev.of_node, DOMAIN_BUS_PCI_MSI);
        if (d)
                return d;

        return irq_find_host(bus->dev.of_node);
#else
        return NULL;
#endif
}

static inline int __of_pci_pci_compare(struct device_node *node,
                                       unsigned int data)
{
        int devfn;

        devfn = of_pci_get_devfn(node);
        if (devfn < 0)
                return 0;

        return devfn == data;
}

struct device_node *of_pci_find_child_device(struct device_node *parent,
                                             unsigned int devfn)
{
        struct device_node *node, *node2;

        for_each_child_of_node(parent, node) {
                if (__of_pci_pci_compare(node, devfn))
                        return node;
                /*
                 * Some OFs create a parent node "multifunc-device" as
                 * a fake root for all functions of a multi-function
                 * device we go down them as well.
                 */
                if (of_node_name_eq(node, "multifunc-device")) {
                        for_each_child_of_node(node, node2) {
                                if (__of_pci_pci_compare(node2, devfn)) {
                                        of_node_put(node);
                                        return node2;
                                }
                        }
                }
        }
        return NULL;
}
EXPORT_SYMBOL_GPL(of_pci_find_child_device);

/**
 * of_pci_get_devfn() - Get device and function numbers for a device node
 * @np: device node
 *
 * Parses a standard 5-cell PCI resource and returns an 8-bit value that can
 * be passed to the PCI_SLOT() and PCI_FUNC() macros to extract the device
 * and function numbers respectively. On error a negative error code is
 * returned.
 */
int of_pci_get_devfn(struct device_node *np)
{
        u32 reg[5];
        int error;

        error = of_property_read_u32_array(np, "reg", reg, ARRAY_SIZE(reg));
        if (error)
                return error;

        return (reg[0] >> 8) & 0xff;
}
EXPORT_SYMBOL_GPL(of_pci_get_devfn);

/**
 * of_pci_parse_bus_range() - parse the bus-range property of a PCI device
 * @node: device node
 * @res: address to a struct resource to return the bus-range
 *
 * Returns 0 on success or a negative error-code on failure.
 */
int of_pci_parse_bus_range(struct device_node *node, struct resource *res)
{
        u32 bus_range[2];
        int error;

        error = of_property_read_u32_array(node, "bus-range", bus_range,
                                           ARRAY_SIZE(bus_range));
        if (error)
                return error;

        res->name = node->name;
        res->start = bus_range[0];
        res->end = bus_range[1];
        res->flags = IORESOURCE_BUS;

        return 0;
}
EXPORT_SYMBOL_GPL(of_pci_parse_bus_range);

/**
 * This function will try to obtain the host bridge domain number by
 * finding a property called "linux,pci-domain" of the given device node.
 *
 * @node: device tree node with the domain information
 *
 * Returns the associated domain number from DT in the range [0-0xffff], or
 * a negative value if the required property is not found.
 */
int of_get_pci_domain_nr(struct device_node *node)
{
        u32 domain;
        int error;

        error = of_property_read_u32(node, "linux,pci-domain", &domain);
        if (error)
                return error;

        return (u16)domain;
}
EXPORT_SYMBOL_GPL(of_get_pci_domain_nr);

/**
 * This function will try to find the limitation of link speed by finding
 * a property called "max-link-speed" of the given device node.
 *
 * @node: device tree node with the max link speed information
 *
 * Returns the associated max link speed from DT, or a negative value if the
 * required property is not found or is invalid.
 */
int of_pci_get_max_link_speed(struct device_node *node)
{
        u32 max_link_speed;

        if (of_property_read_u32(node, "max-link-speed", &max_link_speed) ||
            max_link_speed > 4)
                return -EINVAL;

        return max_link_speed;
}
EXPORT_SYMBOL_GPL(of_pci_get_max_link_speed);

/**
 * of_pci_check_probe_only - Setup probe only mode if linux,pci-probe-only
 *                           is present and valid
 */
void of_pci_check_probe_only(void)
{
        u32 val;
        int ret;

        ret = of_property_read_u32(of_chosen, "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 (val)
                pci_add_flags(PCI_PROBE_ONLY);
        else
                pci_clear_flags(PCI_PROBE_ONLY);

        pr_info("PROBE_ONLY %sabled\n", val ? "en" : "dis");
}
EXPORT_SYMBOL_GPL(of_pci_check_probe_only);

#if defined(CONFIG_OF_ADDRESS)
/**
 * devm_of_pci_get_host_bridge_resources() - Resource-managed parsing of PCI
 *                                           host bridge resources from DT
 * @dev: host bridge device
 * @busno: bus number associated with the bridge root bus
 * @bus_max: maximum number of buses for this bridge
 * @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. Can be NULL if the caller doesn't
 * expect I/O ranges to be present in the device tree.
 *
 * 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.
 *
 * It returns zero if the range parsing has been successful or a standard error
 * value if it failed.
 */
int devm_of_pci_get_host_bridge_resources(struct device *dev,
                        unsigned char busno, unsigned char bus_max,
                        struct list_head *resources, resource_size_t *io_base)
{
        struct device_node *dev_node = dev->of_node;
        struct resource *res, tmp_res;
        struct resource *bus_range;
        struct of_pci_range range;
        struct of_pci_range_parser parser;
        char range_type[4];
        int err;

        if (io_base)
                *io_base = (resource_size_t)OF_BAD_ADDR;

        bus_range = devm_kzalloc(dev, sizeof(*bus_range), GFP_KERNEL);
        if (!bus_range)
                return -ENOMEM;

        dev_info(dev, "host bridge %pOF ranges:\n", dev_node);

        err = of_pci_parse_bus_range(dev_node, bus_range);
        if (err) {
                bus_range->start = busno;
                bus_range->end = bus_max;
                bus_range->flags = IORESOURCE_BUS;
                dev_info(dev, "  No bus range found for %pOF, using %pR\n",
                         dev_node, bus_range);
        } else {
                if (bus_range->end > bus_range->start + bus_max)
                        bus_range->end = bus_range->start + bus_max;
        }
        pci_add_resource(resources, bus_range);

        /* Check for ranges property */
        err = of_pci_range_parser_init(&parser, dev_node);
        if (err)
                goto failed;

        dev_dbg(dev, "Parsing ranges property...\n");
        for_each_of_pci_range(&parser, &range) {
                /* Read next ranges element */
                if ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_IO)
                        snprintf(range_type, 4, " IO");
                else if ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_MEM)
                        snprintf(range_type, 4, "MEM");
                else
                        snprintf(range_type, 4, "err");
                dev_info(dev, "  %s %#010llx..%#010llx -> %#010llx\n",
                         range_type, 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;

                err = of_pci_range_to_resource(&range, dev_node, &tmp_res);
                if (err)
                        continue;

                res = devm_kmemdup(dev, &tmp_res, sizeof(tmp_res), GFP_KERNEL);
                if (!res) {
                        err = -ENOMEM;
                        goto failed;
                }

                if (resource_type(res) == IORESOURCE_IO) {
                        if (!io_base) {
                                dev_err(dev, "I/O range found for %pOF. Please provide an io_base pointer to save CPU base address\n",
                                        dev_node);
                                err = -EINVAL;
                                goto failed;
                        }
                        if (*io_base != (resource_size_t)OF_BAD_ADDR)
                                dev_warn(dev, "More than one I/O resource converted for %pOF. CPU base address for old range lost!\n",
                                         dev_node);
                        *io_base = range.cpu_addr;
                }

                pci_add_resource_offset(resources, res, res->start - range.pci_addr);
        }

        return 0;

failed:
        pci_free_resource_list(resources);
        return err;
}
EXPORT_SYMBOL_GPL(devm_of_pci_get_host_bridge_resources);
#endif /* CONFIG_OF_ADDRESS */

#if IS_ENABLED(CONFIG_OF_IRQ)
/**
 * of_irq_parse_pci - Resolve the interrupt for a PCI device
 * @pdev:       the device whose interrupt is to be resolved
 * @out_irq:    structure of_phandle_args filled by this function
 *
 * This function resolves the PCI interrupt for a given PCI device. If a
 * device-node exists for a given pci_dev, it will use normal OF tree
 * walking. If not, it will implement standard swizzling and walk up the
 * PCI tree until an device-node is found, at which point it will finish
 * resolving using the OF tree walking.
 */
static int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq)
{
        struct device_node *dn, *ppnode;
        struct pci_dev *ppdev;
        __be32 laddr[3];
        u8 pin;
        int rc;

        /*
         * Check if we have a device node, if yes, fallback to standard
         * device tree parsing
         */
        dn = pci_device_to_OF_node(pdev);
        if (dn) {
                rc = of_irq_parse_one(dn, 0, out_irq);
                if (!rc)
                        return rc;
        }

        /*
         * Ok, we don't, time to have fun. Let's start by building up an
         * interrupt spec.  we assume #interrupt-cells is 1, which is standard
         * for PCI. If you do different, then don't use that routine.
         */
        rc = pci_read_config_byte(pdev, PCI_INTERRUPT_PIN, &pin);
        if (rc != 0)
                goto err;
        /* No pin, exit with no error message. */
        if (pin == 0)
                return -ENODEV;

        /* Now we walk up the PCI tree */
        for (;;) {
                /* Get the pci_dev of our parent */
                ppdev = pdev->bus->self;

                /* Ouch, it's a host bridge... */
                if (ppdev == NULL) {
                        ppnode = pci_bus_to_OF_node(pdev->bus);

                        /* No node for host bridge ? give up */
                        if (ppnode == NULL) {
                                rc = -EINVAL;
                                goto err;
                        }
                } else {
                        /* We found a P2P bridge, check if it has a node */
                        ppnode = pci_device_to_OF_node(ppdev);
                }

                /*
                 * Ok, we have found a parent with a device-node, hand over to
                 * the OF parsing code.
                 * We build a unit address from the linux device to be used for
                 * resolution. Note that we use the linux bus number which may
                 * not match your firmware bus numbering.
                 * Fortunately, in most cases, interrupt-map-mask doesn't
                 * include the bus number as part of the matching.
                 * You should still be careful about that though if you intend
                 * to rely on this function (you ship a firmware that doesn't
                 * create device nodes for all PCI devices).
                 */
                if (ppnode)
                        break;

                /*
                 * We can only get here if we hit a P2P bridge with no node;
                 * let's do standard swizzling and try again
                 */
                pin = pci_swizzle_interrupt_pin(pdev, pin);
                pdev = ppdev;
        }

        out_irq->np = ppnode;
        out_irq->args_count = 1;
        out_irq->args[0] = pin;
        laddr[0] = cpu_to_be32((pdev->bus->number << 16) | (pdev->devfn << 8));
        laddr[1] = laddr[2] = cpu_to_be32(0);
        rc = of_irq_parse_raw(laddr, out_irq);
        if (rc)
                goto err;
        return 0;
err:
        if (rc == -ENOENT) {
                dev_warn(&pdev->dev,
                        "%s: no interrupt-map found, INTx interrupts not available\n",
                        __func__);
                pr_warn_once("%s: possibly some PCI slots don't have level triggered interrupts capability\n",
                        __func__);
        } else {
                dev_err(&pdev->dev, "%s: failed with rc=%d\n", __func__, rc);
        }
        return rc;
}

/**
 * of_irq_parse_and_map_pci() - Decode a PCI IRQ from the device tree and map to a VIRQ
 * @dev: The PCI device needing an IRQ
 * @slot: PCI slot number; passed when used as map_irq callback. Unused
 * @pin: PCI IRQ pin number; passed when used as map_irq callback. Unused
 *
 * @slot and @pin are unused, but included in the function so that this
 * function can be used directly as the map_irq callback to
 * pci_assign_irq() and struct pci_host_bridge.map_irq pointer
 */
int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin)
{
        struct of_phandle_args oirq;
        int ret;

        ret = of_irq_parse_pci(dev, &oirq);
        if (ret)
                return 0; /* Proper return code 0 == NO_IRQ */

        return irq_create_of_mapping(&oirq);
}
EXPORT_SYMBOL_GPL(of_irq_parse_and_map_pci);
#endif  /* CONFIG_OF_IRQ */

int pci_parse_request_of_pci_ranges(struct device *dev,
                                    struct list_head *resources,
                                    struct resource **bus_range)
{
        int err, res_valid = 0;
        resource_size_t iobase;
        struct resource_entry *win, *tmp;

        INIT_LIST_HEAD(resources);
        err = devm_of_pci_get_host_bridge_resources(dev, 0, 0xff, resources,
                                                    &iobase);
        if (err)
                return err;

        err = devm_request_pci_bus_resources(dev, resources);
        if (err)
                goto out_release_res;

        resource_list_for_each_entry_safe(win, tmp, resources) {
                struct resource *res = win->res;

                switch (resource_type(res)) {
                case IORESOURCE_IO:
                        err = devm_pci_remap_iospace(dev, res, iobase);
                        if (err) {
                                dev_warn(dev, "error %d: failed to map resource %pR\n",
                                         err, res);
                                resource_list_destroy_entry(win);
                        }
                        break;
                case IORESOURCE_MEM:
                        res_valid |= !(res->flags & IORESOURCE_PREFETCH);
                        break;
                case IORESOURCE_BUS:
                        if (bus_range)
                                *bus_range = res;
                        break;
                }
        }

        if (res_valid)
                return 0;

        dev_err(dev, "non-prefetchable memory resource required\n");
        err = -EINVAL;

 out_release_res:
        pci_free_resource_list(resources);
        return err;
}
EXPORT_SYMBOL_GPL(pci_parse_request_of_pci_ranges);