// SPDX-License-Identifier: GPL-2.0
/*
 * From setup-res.c, by:
 *      Dave Rusling (david.rusling@reo.mts.dec.com)
 *      David Mosberger (davidm@cs.arizona.edu)
 *      David Miller (davem@redhat.com)
 *      Ivan Kokshaysky (ink@jurassic.park.msu.ru)
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/cleanup.h>
#include <linux/pci.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/proc_fs.h>
#include <linux/slab.h>

#include "pci.h"

/*
 * The first PCI_BRIDGE_RESOURCE_NUM PCI bus resources (those that correspond
 * to P2P or CardBus bridge windows) go in a table.  Additional ones (for
 * buses below host bridges or subtractive decode bridges) go in the list.
 * Use pci_bus_for_each_resource() to iterate through all the resources.
 */

struct pci_bus_resource {
        struct list_head        list;
        struct resource         *res;
};

void pci_add_resource_offset(struct list_head *resources, struct resource *res,
                             resource_size_t offset)
{
        struct resource_entry *entry;

        entry = resource_list_create_entry(res, 0);
        if (!entry) {
                pr_err("PCI: can't add host bridge window %pR\n", res);
                return;
        }

        entry->offset = offset;
        resource_list_add_tail(entry, resources);
}
EXPORT_SYMBOL(pci_add_resource_offset);

void pci_add_resource(struct list_head *resources, struct resource *res)
{
        pci_add_resource_offset(resources, res, 0);
}
EXPORT_SYMBOL(pci_add_resource);

void pci_free_resource_list(struct list_head *resources)
{
        resource_list_free(resources);
}
EXPORT_SYMBOL(pci_free_resource_list);

void pci_bus_add_resource(struct pci_bus *bus, struct resource *res)
{
        struct pci_bus_resource *bus_res;

        bus_res = kzalloc_obj(struct pci_bus_resource);
        if (!bus_res) {
                dev_err(&bus->dev, "can't add %pR resource\n", res);
                return;
        }

        bus_res->res = res;
        list_add_tail(&bus_res->list, &bus->resources);
}

struct resource *pci_bus_resource_n(const struct pci_bus *bus, int n)
{
        struct pci_bus_resource *bus_res;

        if (n < PCI_BRIDGE_RESOURCE_NUM)
                return bus->resource[n];

        n -= PCI_BRIDGE_RESOURCE_NUM;
        list_for_each_entry(bus_res, &bus->resources, list) {
                if (n-- == 0)
                        return bus_res->res;
        }
        return NULL;
}
EXPORT_SYMBOL_GPL(pci_bus_resource_n);

void pci_bus_remove_resource(struct pci_bus *bus, struct resource *res)
{
        struct pci_bus_resource *bus_res, *tmp;
        int i;

        for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++) {
                if (bus->resource[i] == res) {
                        bus->resource[i] = NULL;
                        return;
                }
        }

        list_for_each_entry_safe(bus_res, tmp, &bus->resources, list) {
                if (bus_res->res == res) {
                        list_del(&bus_res->list);
                        kfree(bus_res);
                        return;
                }
        }
}

void pci_bus_remove_resources(struct pci_bus *bus)
{
        int i;
        struct pci_bus_resource *bus_res, *tmp;

        for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++)
                bus->resource[i] = NULL;

        list_for_each_entry_safe(bus_res, tmp, &bus->resources, list) {
                list_del(&bus_res->list);
                kfree(bus_res);
        }
}

int devm_request_pci_bus_resources(struct device *dev,
                                   struct list_head *resources)
{
        struct resource_entry *win;
        struct resource *parent, *res;
        int err;

        resource_list_for_each_entry(win, resources) {
                res = win->res;
                switch (resource_type(res)) {
                case IORESOURCE_IO:
                        parent = &ioport_resource;
                        break;
                case IORESOURCE_MEM:
                        parent = &iomem_resource;
                        break;
                default:
                        continue;
                }

                err = devm_request_resource(dev, parent, res);
                if (err)
                        return err;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(devm_request_pci_bus_resources);

static struct pci_bus_region pci_32_bit = {0, 0xffffffffULL};
#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
static struct pci_bus_region pci_64_bit = {0,
                                (pci_bus_addr_t) 0xffffffffffffffffULL};
static struct pci_bus_region pci_high = {(pci_bus_addr_t) 0x100000000ULL,
                                (pci_bus_addr_t) 0xffffffffffffffffULL};
#endif

/*
 * @res contains CPU addresses.  Clip it so the corresponding bus addresses
 * on @bus are entirely within @region.  This is used to control the bus
 * addresses of resources we allocate, e.g., we may need a resource that
 * can be mapped by a 32-bit BAR.
 */
static void pci_clip_resource_to_region(struct pci_bus *bus,
                                        struct resource *res,
                                        struct pci_bus_region *region)
{
        struct pci_bus_region r;

        pcibios_resource_to_bus(bus, &r, res);
        if (r.start < region->start)
                r.start = region->start;
        if (r.end > region->end)
                r.end = region->end;

        if (r.end < r.start)
                res->end = res->start - 1;
        else
                pcibios_bus_to_resource(bus, res, &r);
}

static int pci_bus_alloc_from_region(struct pci_bus *bus, struct resource *res,
                resource_size_t size, resource_size_t align,
                resource_size_t min, unsigned long type_mask,
                resource_alignf alignf,
                void *alignf_data,
                struct pci_bus_region *region)
{
        struct resource *r, avail;
        resource_size_t max;
        int ret;

        type_mask |= IORESOURCE_TYPE_BITS;

        pci_bus_for_each_resource(bus, r) {
                resource_size_t min_used = min;

                if (!r)
                        continue;

                if (r->flags & (IORESOURCE_UNSET|IORESOURCE_DISABLED))
                        continue;

                /* type_mask must match */
                if ((res->flags ^ r->flags) & type_mask)
                        continue;

                /* We cannot allocate a non-prefetching resource
                   from a pre-fetching area */
                if ((r->flags & IORESOURCE_PREFETCH) &&
                    !(res->flags & IORESOURCE_PREFETCH))
                        continue;

                avail = *r;
                pci_clip_resource_to_region(bus, &avail, region);

                /*
                 * "min" is typically PCIBIOS_MIN_IO or PCIBIOS_MIN_MEM to
                 * protect badly documented motherboard resources, but if
                 * this is an already-configured bridge window, its start
                 * overrides "min".
                 */
                if (avail.start)
                        min_used = avail.start;

                max = avail.end;

                /* Don't bother if available space isn't large enough */
                if (size > max - min_used + 1)
                        continue;

                /* Ok, try it out.. */
                ret = allocate_resource(r, res, size, min_used, max,
                                        align, alignf, alignf_data);
                if (ret == 0)
                        return 0;
        }
        return -ENOMEM;
}

/**
 * pci_bus_alloc_resource - allocate a resource from a parent bus
 * @bus: PCI bus
 * @res: resource to allocate
 * @size: size of resource to allocate
 * @align: alignment of resource to allocate
 * @min: minimum /proc/iomem address to allocate
 * @type_mask: IORESOURCE_* type flags
 * @alignf: resource alignment function
 * @alignf_data: data argument for resource alignment function
 *
 * Given the PCI bus a device resides on, the size, minimum address,
 * alignment and type, try to find an acceptable resource allocation
 * for a specific device resource.
 */
int pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
                resource_size_t size, resource_size_t align,
                resource_size_t min, unsigned long type_mask,
                resource_alignf alignf,
                void *alignf_data)
{
#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
        int rc;

        if (res->flags & IORESOURCE_MEM_64) {
                rc = pci_bus_alloc_from_region(bus, res, size, align, min,
                                               type_mask, alignf, alignf_data,
                                               &pci_high);
                if (rc == 0)
                        return 0;

                return pci_bus_alloc_from_region(bus, res, size, align, min,
                                                 type_mask, alignf, alignf_data,
                                                 &pci_64_bit);
        }
#endif

        return pci_bus_alloc_from_region(bus, res, size, align, min,
                                         type_mask, alignf, alignf_data,
                                         &pci_32_bit);
}
EXPORT_SYMBOL(pci_bus_alloc_resource);

/*
 * The @idx resource of @dev should be a PCI-PCI bridge window.  If this
 * resource fits inside a window of an upstream bridge, do nothing.  If it
 * overlaps an upstream window but extends outside it, clip the resource so
 * it fits completely inside.
 */
bool pci_bus_clip_resource(struct pci_dev *dev, int idx)
{
        struct pci_bus *bus = dev->bus;
        struct resource *res = &dev->resource[idx];
        struct resource orig_res = *res;
        struct resource *r;

        pci_bus_for_each_resource(bus, r) {
                resource_size_t start, end;

                if (!r)
                        continue;

                if (resource_type(res) != resource_type(r))
                        continue;

                start = max(r->start, res->start);
                end = min(r->end, res->end);

                if (start > end)
                        continue;       /* no overlap */

                if (res->start == start && res->end == end)
                        return false;   /* no change */

                res->start = start;
                res->end = end;
                res->flags &= ~IORESOURCE_UNSET;
                orig_res.flags &= ~IORESOURCE_UNSET;
                pci_info(dev, "%pR clipped to %pR\n", &orig_res, res);

                return true;
        }

        return false;
}

void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { }

void __weak pcibios_bus_add_device(struct pci_dev *pdev) { }

/**
 * pci_bus_add_device - start driver for a single device
 * @dev: device to add
 *
 * This adds add sysfs entries and start device drivers
 */
void pci_bus_add_device(struct pci_dev *dev)
{
        struct device_node *dn = dev->dev.of_node;

        /*
         * Can not put in pci_device_add yet because resources
         * are not assigned yet for some devices.
         */
        pcibios_bus_add_device(dev);
        pci_fixup_device(pci_fixup_final, dev);
        if (pci_is_bridge(dev))
                of_pci_make_dev_node(dev);
        pci_create_sysfs_dev_files(dev);
        pci_proc_attach_device(dev);
        pci_bridge_d3_update(dev);

        /* Save config space for error recoverability */
        pci_save_state(dev);

        /*
         * Enable runtime PM, which potentially allows the device to
         * suspend immediately, only after the PCI state has been
         * configured completely.
         */
        pm_runtime_enable(&dev->dev);

        if (!dn || of_device_is_available(dn))
                pci_dev_allow_binding(dev);

        device_initial_probe(&dev->dev);

        pci_dev_assign_added(dev);
}
EXPORT_SYMBOL_GPL(pci_bus_add_device);

/**
 * pci_bus_add_devices - start driver for PCI devices
 * @bus: bus to check for new devices
 *
 * Start driver for PCI devices and add some sysfs entries.
 */
void pci_bus_add_devices(const struct pci_bus *bus)
{
        struct pci_dev *dev;
        struct pci_bus *child;

        list_for_each_entry(dev, &bus->devices, bus_list) {
                /* Skip already-added devices */
                if (pci_dev_is_added(dev))
                        continue;
                pci_bus_add_device(dev);
        }

        list_for_each_entry(dev, &bus->devices, bus_list) {
                /* Skip if device attach failed */
                if (!pci_dev_is_added(dev))
                        continue;
                child = dev->subordinate;
                if (child)
                        pci_bus_add_devices(child);
        }
}
EXPORT_SYMBOL(pci_bus_add_devices);

static int __pci_walk_bus(struct pci_bus *top, int (*cb)(struct pci_dev *, void *),
                          void *userdata)
{
        struct pci_dev *dev;
        int ret = 0;

        list_for_each_entry(dev, &top->devices, bus_list) {
                ret = cb(dev, userdata);
                if (ret)
                        break;
                if (dev->subordinate) {
                        ret = __pci_walk_bus(dev->subordinate, cb, userdata);
                        if (ret)
                                break;
                }
        }
        return ret;
}

static int __pci_walk_bus_reverse(struct pci_bus *top,
                                  int (*cb)(struct pci_dev *, void *),
                                  void *userdata)
{
        struct pci_dev *dev;
        int ret = 0;

        list_for_each_entry_reverse(dev, &top->devices, bus_list) {
                if (dev->subordinate) {
                        ret = __pci_walk_bus_reverse(dev->subordinate, cb,
                                                     userdata);
                        if (ret)
                                break;
                }
                ret = cb(dev, userdata);
                if (ret)
                        break;
        }
        return ret;
}

/**
 *  pci_walk_bus - walk devices on/under bus, calling callback.
 *  @top: bus whose devices should be walked
 *  @cb: callback to be called for each device found
 *  @userdata: arbitrary pointer to be passed to callback
 *
 *  Walk the given bus, including any bridged devices
 *  on buses under this bus.  Call the provided callback
 *  on each device found.
 *
 *  We check the return of @cb each time. If it returns anything
 *  other than 0, we break out.
 */
void pci_walk_bus(struct pci_bus *top, int (*cb)(struct pci_dev *, void *), void *userdata)
{
        down_read(&pci_bus_sem);
        __pci_walk_bus(top, cb, userdata);
        up_read(&pci_bus_sem);
}
EXPORT_SYMBOL_GPL(pci_walk_bus);

/**
 * pci_walk_bus_reverse - walk devices on/under bus, calling callback.
 * @top: bus whose devices should be walked
 * @cb: callback to be called for each device found
 * @userdata: arbitrary pointer to be passed to callback
 *
 * Same semantics as pci_walk_bus(), but walks the bus in reverse order.
 */
void pci_walk_bus_reverse(struct pci_bus *top,
                          int (*cb)(struct pci_dev *, void *), void *userdata)
{
        down_read(&pci_bus_sem);
        __pci_walk_bus_reverse(top, cb, userdata);
        up_read(&pci_bus_sem);
}
EXPORT_SYMBOL_GPL(pci_walk_bus_reverse);

void pci_walk_bus_locked(struct pci_bus *top, int (*cb)(struct pci_dev *, void *), void *userdata)
{
        lockdep_assert_held(&pci_bus_sem);

        __pci_walk_bus(top, cb, userdata);
}

struct pci_bus *pci_bus_get(struct pci_bus *bus)
{
        if (bus)
                get_device(&bus->dev);
        return bus;
}

void pci_bus_put(struct pci_bus *bus)
{
        if (bus)
                put_device(&bus->dev);
}