// SPDX-License-Identifier: GPL-2.0+
/*
 * Device tree based initialization code for reserved memory.
 *
 * Copyright (c) 2013, 2015 The Linux Foundation. All Rights Reserved.
 * Copyright (c) 2013,2014 Samsung Electronics Co., Ltd.
 *              http://www.samsung.com
 * Author: Marek Szyprowski <m.szyprowski@samsung.com>
 * Author: Josh Cartwright <joshc@codeaurora.org>
 */

#define pr_fmt(fmt)     "OF: reserved mem: " fmt

#include <linux/err.h>
#include <linux/ioport.h>
#include <linux/libfdt.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/of_platform.h>
#include <linux/mm.h>
#include <linux/sizes.h>
#include <linux/of_reserved_mem.h>
#include <linux/sort.h>
#include <linux/slab.h>
#include <linux/memblock.h>
#include <linux/kmemleak.h>

#include "of_private.h"

static struct reserved_mem reserved_mem_array[MAX_RESERVED_REGIONS] __initdata;
static struct reserved_mem *reserved_mem __refdata = reserved_mem_array;
static int total_reserved_mem_cnt = MAX_RESERVED_REGIONS;
static int reserved_mem_count;

static int __init early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
        phys_addr_t align, phys_addr_t start, phys_addr_t end, bool nomap,
        phys_addr_t *res_base)
{
        phys_addr_t base;
        int err = 0;

        end = !end ? MEMBLOCK_ALLOC_ANYWHERE : end;
        align = !align ? SMP_CACHE_BYTES : align;
        base = memblock_phys_alloc_range(size, align, start, end);
        if (!base)
                return -ENOMEM;

        *res_base = base;
        if (nomap) {
                err = memblock_mark_nomap(base, size);
                if (err)
                        memblock_phys_free(base, size);
        }

        if (!err)
                kmemleak_ignore_phys(base);

        return err;
}

/*
 * alloc_reserved_mem_array() - allocate memory for the reserved_mem
 * array using memblock
 *
 * This function is used to allocate memory for the reserved_mem
 * array according to the total number of reserved memory regions
 * defined in the DT.
 * After the new array is allocated, the information stored in
 * the initial static array is copied over to this new array and
 * the new array is used from this point on.
 */
static int __init alloc_reserved_mem_array(void)
{
        struct reserved_mem *new_array;
        size_t alloc_size, copy_size, memset_size;
        int ret;

        if (!total_reserved_mem_cnt)
                return 0;

        alloc_size = array_size(total_reserved_mem_cnt, sizeof(*new_array));
        if (alloc_size == SIZE_MAX) {
                ret = -EOVERFLOW;
                goto fail;
        }

        new_array = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
        if (!new_array) {
                ret = -ENOMEM;
                goto fail;
        }

        copy_size = array_size(reserved_mem_count, sizeof(*new_array));
        if (copy_size == SIZE_MAX) {
                memblock_free(new_array, alloc_size);
                ret = -EOVERFLOW;
                goto fail;
        }

        memset_size = alloc_size - copy_size;

        memcpy(new_array, reserved_mem, copy_size);
        memset(new_array + reserved_mem_count, 0, memset_size);

        reserved_mem = new_array;
        return 0;

fail:
        pr_err("Failed to allocate memory for reserved_mem array with err: %d", ret);
        reserved_mem_count = 0;
        return ret;
}

static void fdt_init_reserved_mem_node(unsigned long node, const char *uname,
                                       phys_addr_t base, phys_addr_t size);
static int fdt_validate_reserved_mem_node(unsigned long node,
                                          phys_addr_t *align);
static int fdt_fixup_reserved_mem_node(unsigned long node,
                                       phys_addr_t base, phys_addr_t size);

static int __init early_init_dt_reserve_memory(phys_addr_t base,
                                               phys_addr_t size, bool nomap)
{
        if (nomap) {
                /*
                 * If the memory is already reserved (by another region), we
                 * should not allow it to be marked nomap, but don't worry
                 * if the region isn't memory as it won't be mapped.
                 */
                if (memblock_overlaps_region(&memblock.memory, base, size) &&
                    memblock_is_region_reserved(base, size))
                        return -EBUSY;

                return memblock_mark_nomap(base, size);
        }
        return memblock_reserve(base, size);
}

/*
 * __reserved_mem_reserve_reg() - reserve memory described in the
 * first entry in 'reg' property
 */
static int __init __reserved_mem_reserve_reg(unsigned long node,
                                             const char *uname)
{
        phys_addr_t base, size;
        int len, err;
        const __be32 *prop;
        bool nomap;
        u64 b, s;

        prop = of_flat_dt_get_addr_size_prop(node, "reg", &len);
        if (!prop || !len)
                return -ENOENT;

        if (len > 1)
                pr_warn("Reserved memory: node '%s' has %d <base size> entries, only the first is used\n",
                        uname, len);

        nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;

        err = fdt_validate_reserved_mem_node(node, NULL);
        if (err && err != -ENODEV)
                return err;

        of_flat_dt_read_addr_size(prop, 0, &b, &s);
        base = b;
        size = s;

        if (size && early_init_dt_reserve_memory(base, size, nomap) == 0) {
                fdt_fixup_reserved_mem_node(node, base, size);
                pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
                         uname, &base, (unsigned long)(size / SZ_1M));
        } else {
                pr_err("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n",
                       uname, &base, (unsigned long)(size / SZ_1M));
        }
        return 0;
}

/*
 * __reserved_mem_check_root() - check if #size-cells, #address-cells provided
 * in /reserved-memory matches the values supported by the current implementation,
 * also check if ranges property has been provided
 */
static int __init __reserved_mem_check_root(unsigned long node)
{
        const __be32 *prop;

        prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
        if (!prop || be32_to_cpup(prop) != dt_root_size_cells)
                return -EINVAL;

        prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
        if (!prop || be32_to_cpup(prop) != dt_root_addr_cells)
                return -EINVAL;

        prop = of_get_flat_dt_prop(node, "ranges", NULL);
        if (!prop)
                return -EINVAL;
        return 0;
}

static int __init __rmem_cmp(const void *a, const void *b)
{
        const struct reserved_mem *ra = a, *rb = b;

        if (ra->base < rb->base)
                return -1;

        if (ra->base > rb->base)
                return 1;

        /*
         * Put the dynamic allocations (address == 0, size == 0) before static
         * allocations at address 0x0 so that overlap detection works
         * correctly.
         */
        if (ra->size < rb->size)
                return -1;
        if (ra->size > rb->size)
                return 1;

        return 0;
}

static void __init __rmem_check_for_overlap(void)
{
        int i;

        if (reserved_mem_count < 2)
                return;

        sort(reserved_mem, reserved_mem_count, sizeof(reserved_mem[0]),
             __rmem_cmp, NULL);
        for (i = 0; i < reserved_mem_count - 1; i++) {
                struct reserved_mem *this, *next;

                this = &reserved_mem[i];
                next = &reserved_mem[i + 1];

                if (this->base + this->size > next->base) {
                        phys_addr_t this_end, next_end;

                        this_end = this->base + this->size;
                        next_end = next->base + next->size;
                        pr_err("OVERLAP DETECTED!\n%s (%pa--%pa) overlaps with %s (%pa--%pa)\n",
                               this->name, &this->base, &this_end,
                               next->name, &next->base, &next_end);
                }
        }
}

/**
 * fdt_scan_reserved_mem_late() - Scan FDT and initialize remaining reserved
 * memory regions.
 *
 * This function is used to scan again through the DT and initialize the
 * "static" reserved memory regions, that are defined using the "reg"
 * property. Each such region is then initialized with its specific init
 * function and stored in the global reserved_mem array.
 */
void __init fdt_scan_reserved_mem_late(void)
{
        const void *fdt = initial_boot_params;
        phys_addr_t base, size;
        int node, child;

        if (!fdt)
                return;

        node = fdt_path_offset(fdt, "/reserved-memory");
        if (node < 0) {
                pr_info("Reserved memory: No reserved-memory node in the DT\n");
                return;
        }

        /* Attempt dynamic allocation of a new reserved_mem array */
        if (alloc_reserved_mem_array())
                return;

        if (__reserved_mem_check_root(node)) {
                pr_err("Reserved memory: unsupported node format, ignoring\n");
                return;
        }

        fdt_for_each_subnode(child, fdt, node) {
                const __be32 *prop;
                const char *uname;
                u64 b, s;
                int ret;
                int len;

                if (!of_fdt_device_is_available(fdt, child))
                        continue;

                prop = of_flat_dt_get_addr_size_prop(child, "reg", &len);
                if (!prop || !len)
                        continue;

                ret = fdt_validate_reserved_mem_node(child, NULL);
                if (ret && ret != -ENODEV)
                        continue;

                of_flat_dt_read_addr_size(prop, 0, &b, &s);
                base = b;
                size = s;

                if (size) {
                        uname = fdt_get_name(fdt, child, NULL);
                        fdt_init_reserved_mem_node(child, uname, base, size);
                }
        }

        /* check for overlapping reserved regions */
        __rmem_check_for_overlap();
}

static int __init __reserved_mem_alloc_size(unsigned long node, const char *uname);

/*
 * fdt_scan_reserved_mem() - reserve and allocate memory occupied by
 * reserved memory regions.
 *
 * This function is used to scan through the FDT and mark memory occupied
 * by all static (defined by the "reg" property) reserved memory regions.
 * Then memory for all dynamic regions (defined by size & alignment) is
 * allocated, a region specific init function is called and region information
 * is stored in the reserved_mem array.
 */
int __init fdt_scan_reserved_mem(void)
{
        int node, child;
        int dynamic_nodes_cnt = 0, count = 0;
        int dynamic_nodes[MAX_RESERVED_REGIONS];
        const void *fdt = initial_boot_params;

        node = fdt_path_offset(fdt, "/reserved-memory");
        if (node < 0) {
                total_reserved_mem_cnt = 0;
                return -ENODEV;
        }

        if (__reserved_mem_check_root(node) != 0) {
                pr_err("Reserved memory: unsupported node format, ignoring\n");
                total_reserved_mem_cnt = 0;
                return -EINVAL;
        }

        fdt_for_each_subnode(child, fdt, node) {
                const char *uname;
                int err;

                if (!of_fdt_device_is_available(fdt, child))
                        continue;

                uname = fdt_get_name(fdt, child, NULL);

                err = __reserved_mem_reserve_reg(child, uname);
                if (!err)
                        count++;
                /*
                 * Save the nodes for the dynamically-placed regions
                 * into an array which will be used for allocation right
                 * after all the statically-placed regions are reserved
                 * or marked as no-map. This is done to avoid dynamically
                 * allocating from one of the statically-placed regions.
                 */
                if (err == -ENOENT && of_get_flat_dt_prop(child, "size", NULL)) {
                        dynamic_nodes[dynamic_nodes_cnt] = child;
                        dynamic_nodes_cnt++;
                }
        }
        for (int i = 0; i < dynamic_nodes_cnt; i++) {
                const char *uname;
                int err;

                child = dynamic_nodes[i];
                uname = fdt_get_name(fdt, child, NULL);
                err = __reserved_mem_alloc_size(child, uname);
                if (!err)
                        count++;
        }
        total_reserved_mem_cnt = count;
        return 0;
}

/*
 * __reserved_mem_alloc_in_range() - allocate reserved memory described with
 *      'alloc-ranges'. Choose bottom-up/top-down depending on nearby existing
 *      reserved regions to keep the reserved memory contiguous if possible.
 */
static int __init __reserved_mem_alloc_in_range(phys_addr_t size,
        phys_addr_t align, phys_addr_t start, phys_addr_t end, bool nomap,
        phys_addr_t *res_base)
{
        bool prev_bottom_up = memblock_bottom_up();
        bool bottom_up = false, top_down = false;
        int ret, i;

        for (i = 0; i < reserved_mem_count; i++) {
                struct reserved_mem *rmem = &reserved_mem[i];

                /* Skip regions that were not reserved yet */
                if (rmem->size == 0)
                        continue;

                /*
                 * If range starts next to an existing reservation, use bottom-up:
                 *      |....RRRR................RRRRRRRR..............|
                 *             --RRRR------
                 */
                if (start >= rmem->base && start <= (rmem->base + rmem->size))
                        bottom_up = true;

                /*
                 * If range ends next to an existing reservation, use top-down:
                 *      |....RRRR................RRRRRRRR..............|
                 *                    -------RRRR-----
                 */
                if (end >= rmem->base && end <= (rmem->base + rmem->size))
                        top_down = true;
        }

        /* Change setting only if either bottom-up or top-down was selected */
        if (bottom_up != top_down)
                memblock_set_bottom_up(bottom_up);

        ret = early_init_dt_alloc_reserved_memory_arch(size, align,
                        start, end, nomap, res_base);

        /* Restore old setting if needed */
        if (bottom_up != top_down)
                memblock_set_bottom_up(prev_bottom_up);

        return ret;
}

/*
 * __reserved_mem_alloc_size() - allocate reserved memory described by
 *      'size', 'alignment'  and 'alloc-ranges' properties.
 */
static int __init __reserved_mem_alloc_size(unsigned long node, const char *uname)
{
        phys_addr_t start = 0, end = 0;
        phys_addr_t base = 0, align = 0, size;
        int i, len;
        const __be32 *prop;
        bool nomap;
        int ret;

        prop = of_get_flat_dt_prop(node, "size", &len);
        if (!prop)
                return -EINVAL;

        if (len != dt_root_size_cells * sizeof(__be32)) {
                pr_err("invalid size property in '%s' node.\n", uname);
                return -EINVAL;
        }
        size = dt_mem_next_cell(dt_root_size_cells, &prop);

        prop = of_get_flat_dt_prop(node, "alignment", &len);
        if (prop) {
                if (len != dt_root_addr_cells * sizeof(__be32)) {
                        pr_err("invalid alignment property in '%s' node.\n",
                                uname);
                        return -EINVAL;
                }
                align = dt_mem_next_cell(dt_root_addr_cells, &prop);
        }

        nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;

        ret = fdt_validate_reserved_mem_node(node, &align);
        if (ret && ret != -ENODEV)
                return ret;

        prop = of_flat_dt_get_addr_size_prop(node, "alloc-ranges", &len);
        if (prop) {
                for (i = 0; i < len; i++) {
                        u64 b, s;

                        of_flat_dt_read_addr_size(prop, i, &b, &s);

                        start = b;
                        end = b + s;

                        base = 0;
                        ret = __reserved_mem_alloc_in_range(size, align,
                                        start, end, nomap, &base);
                        if (ret == 0) {
                                pr_debug("allocated memory for '%s' node: base %pa, size %lu MiB\n",
                                        uname, &base,
                                        (unsigned long)(size / SZ_1M));
                                break;
                        }
                }
        } else {
                ret = early_init_dt_alloc_reserved_memory_arch(size, align,
                                                        0, 0, nomap, &base);
                if (ret == 0)
                        pr_debug("allocated memory for '%s' node: base %pa, size %lu MiB\n",
                                uname, &base, (unsigned long)(size / SZ_1M));
        }

        if (base == 0) {
                pr_err("failed to allocate memory for node '%s': size %lu MiB\n",
                       uname, (unsigned long)(size / SZ_1M));
                return -ENOMEM;
        }

        fdt_fixup_reserved_mem_node(node, base, size);
        fdt_init_reserved_mem_node(node, uname, base, size);

        return 0;
}

extern const struct of_device_id __reservedmem_of_table[];
static const struct of_device_id __rmem_of_table_sentinel
        __used __section("__reservedmem_of_table_end");

/**
 * fdt_fixup_reserved_mem_node() - call fixup function for a reserved memory node
 * @node: FDT node to fixup
 * @base: base address of the reserved memory region
 * @size: size of the reserved memory region
 *
 * This function iterates through the reserved memory drivers and calls
 * the node_fixup callback for the compatible entry matching the node.
 *
 * Return: 0 on success, -ENODEV if no compatible match found
 */
static int __init fdt_fixup_reserved_mem_node(unsigned long node,
                                        phys_addr_t base, phys_addr_t size)
{
        const struct of_device_id *i;
        int ret = -ENODEV;

        for (i = __reservedmem_of_table; ret == -ENODEV &&
             i < &__rmem_of_table_sentinel; i++) {
                const struct reserved_mem_ops *ops = i->data;

                if (!of_flat_dt_is_compatible(node, i->compatible))
                        continue;

                if (ops->node_fixup)
                        ret = ops->node_fixup(node, base, size);
        }
        return ret;
}

/**
 * fdt_validate_reserved_mem_node() - validate a reserved memory node
 * @node: FDT node to validate
 * @align: pointer to store the validated alignment (may be modified by callback)
 *
 * This function iterates through the reserved memory drivers and calls
 * the node_validate callback for the compatible entry matching the node.
 *
 * Return: 0 on success, -ENODEV if no compatible match found
 */
static int __init fdt_validate_reserved_mem_node(unsigned long node, phys_addr_t *align)
{
        const struct of_device_id *i;
        int ret = -ENODEV;

        for (i = __reservedmem_of_table; ret == -ENODEV &&
             i < &__rmem_of_table_sentinel; i++) {
                const struct reserved_mem_ops *ops = i->data;

                if (!of_flat_dt_is_compatible(node, i->compatible))
                        continue;

                if (ops->node_validate)
                        ret = ops->node_validate(node, align);
        }
        return ret;
}

/**
 * __reserved_mem_init_node() - initialize a reserved memory region
 * @rmem: reserved_mem structure to initialize
 * @node: FDT node describing the reserved memory region
 *
 * This function iterates through the reserved memory drivers and calls the
 * node_init callback for the compatible entry matching the node. On success,
 * the operations pointer is stored in the reserved_mem structure.
 *
 * Return: 0 on success, -ENODEV if no compatible match found
 */
static int __init __reserved_mem_init_node(struct reserved_mem *rmem,
                                           unsigned long node)
{
        const struct of_device_id *i;
        int ret = -ENODEV;

        for (i = __reservedmem_of_table; ret == -ENODEV &&
             i < &__rmem_of_table_sentinel; i++) {
                const struct reserved_mem_ops *ops = i->data;
                const char *compat = i->compatible;

                if (!of_flat_dt_is_compatible(node, compat))
                        continue;

                ret = ops->node_init(node, rmem);
                if (ret == 0) {
                        rmem->ops = ops;
                        pr_info("initialized node %s, compatible id %s\n",
                                rmem->name, compat);
                        return ret;
                }
        }
        return ret;
}

/**
 * fdt_init_reserved_mem_node() - Initialize a reserved memory region
 * @node: fdt node of the initialized region
 * @uname: name of the reserved memory node
 * @base: base address of the reserved memory region
 * @size: size of the reserved memory region
 *
 * This function calls the region-specific initialization function for a
 * reserved memory region and saves all region-specific data to the
 * reserved_mem array to allow of_reserved_mem_lookup() to find it.
 */
static void __init fdt_init_reserved_mem_node(unsigned long node, const char *uname,
                                              phys_addr_t base, phys_addr_t size)
{
        int err = 0;
        bool nomap;

        struct reserved_mem *rmem = &reserved_mem[reserved_mem_count];

        if (reserved_mem_count == total_reserved_mem_cnt) {
                pr_err("not enough space for all defined regions.\n");
                return;
        }

        rmem->name = uname;
        rmem->base = base;
        rmem->size = size;

        nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;

        err = __reserved_mem_init_node(rmem, node);
        if (err != 0 && err != -ENODEV) {
                pr_info("node %s compatible matching fail\n", rmem->name);
                rmem->name = NULL;

                if (nomap)
                        memblock_clear_nomap(rmem->base, rmem->size);
                else
                        memblock_phys_free(rmem->base, rmem->size);
                return;
        } else {
                phys_addr_t end = rmem->base + rmem->size - 1;
                bool reusable =
                        (of_get_flat_dt_prop(node, "reusable", NULL)) != NULL;

                pr_info("%pa..%pa (%lu KiB) %s %s %s\n",
                        &rmem->base, &end, (unsigned long)(rmem->size / SZ_1K),
                        nomap ? "nomap" : "map",
                        reusable ? "reusable" : "non-reusable",
                        rmem->name ? rmem->name : "unknown");
        }

        reserved_mem_count++;
}

struct rmem_assigned_device {
        struct device *dev;
        struct reserved_mem *rmem;
        struct list_head list;
};

static LIST_HEAD(of_rmem_assigned_device_list);
static DEFINE_MUTEX(of_rmem_assigned_device_mutex);

/**
 * of_reserved_mem_device_init_by_idx() - assign reserved memory region to
 *                                        given device
 * @dev:        Pointer to the device to configure
 * @np:         Pointer to the device_node with 'reserved-memory' property
 * @idx:        Index of selected region
 *
 * This function assigns respective DMA-mapping operations based on reserved
 * memory region specified by 'memory-region' property in @np node to the @dev
 * device. When driver needs to use more than one reserved memory region, it
 * should allocate child devices and initialize regions by name for each of
 * child device.
 *
 * Returns error code or zero on success.
 */
int of_reserved_mem_device_init_by_idx(struct device *dev,
                                       struct device_node *np, int idx)
{
        struct rmem_assigned_device *rd;
        struct device_node *target;
        struct reserved_mem *rmem;
        int ret;

        if (!np || !dev)
                return -EINVAL;

        target = of_parse_phandle(np, "memory-region", idx);
        if (!target)
                return -ENODEV;

        if (!of_device_is_available(target)) {
                of_node_put(target);
                return 0;
        }

        rmem = of_reserved_mem_lookup(target);
        of_node_put(target);

        if (!rmem || !rmem->ops || !rmem->ops->device_init)
                return -EINVAL;

        rd = kmalloc_obj(struct rmem_assigned_device);
        if (!rd)
                return -ENOMEM;

        ret = rmem->ops->device_init(rmem, dev);
        if (ret == 0) {
                rd->dev = dev;
                rd->rmem = rmem;

                mutex_lock(&of_rmem_assigned_device_mutex);
                list_add(&rd->list, &of_rmem_assigned_device_list);
                mutex_unlock(&of_rmem_assigned_device_mutex);

                dev_info(dev, "assigned reserved memory node %s\n", rmem->name);
        } else {
                kfree(rd);
        }

        return ret;
}
EXPORT_SYMBOL_GPL(of_reserved_mem_device_init_by_idx);

/**
 * of_reserved_mem_device_init_by_name() - assign named reserved memory region
 *                                         to given device
 * @dev: pointer to the device to configure
 * @np: pointer to the device node with 'memory-region' property
 * @name: name of the selected memory region
 *
 * Returns: 0 on success or a negative error-code on failure.
 */
int of_reserved_mem_device_init_by_name(struct device *dev,
                                        struct device_node *np,
                                        const char *name)
{
        int idx = of_property_match_string(np, "memory-region-names", name);

        return of_reserved_mem_device_init_by_idx(dev, np, idx);
}
EXPORT_SYMBOL_GPL(of_reserved_mem_device_init_by_name);

/**
 * of_reserved_mem_device_release() - release reserved memory device structures
 * @dev:        Pointer to the device to deconfigure
 *
 * This function releases structures allocated for memory region handling for
 * the given device.
 */
void of_reserved_mem_device_release(struct device *dev)
{
        struct rmem_assigned_device *rd, *tmp;
        LIST_HEAD(release_list);

        mutex_lock(&of_rmem_assigned_device_mutex);
        list_for_each_entry_safe(rd, tmp, &of_rmem_assigned_device_list, list) {
                if (rd->dev == dev)
                        list_move_tail(&rd->list, &release_list);
        }
        mutex_unlock(&of_rmem_assigned_device_mutex);

        list_for_each_entry_safe(rd, tmp, &release_list, list) {
                if (rd->rmem && rd->rmem->ops && rd->rmem->ops->device_release)
                        rd->rmem->ops->device_release(rd->rmem, dev);

                kfree(rd);
        }
}
EXPORT_SYMBOL_GPL(of_reserved_mem_device_release);

/**
 * of_reserved_mem_lookup() - acquire reserved_mem from a device node
 * @np:         node pointer of the desired reserved-memory region
 *
 * This function allows drivers to acquire a reference to the reserved_mem
 * struct based on a device node handle.
 *
 * Returns a reserved_mem reference, or NULL on error.
 */
struct reserved_mem *of_reserved_mem_lookup(struct device_node *np)
{
        const char *name;
        int i;

        if (!np->full_name)
                return NULL;

        name = kbasename(np->full_name);
        for (i = 0; i < reserved_mem_count; i++)
                if (reserved_mem[i].name &&
                    !strcmp(reserved_mem[i].name, name))
                        return &reserved_mem[i];

        return NULL;
}
EXPORT_SYMBOL_GPL(of_reserved_mem_lookup);

/**
 * of_reserved_mem_region_to_resource() - Get a reserved memory region as a resource
 * @np:         node containing 'memory-region' property
 * @idx:        index of 'memory-region' property to lookup
 * @res:        Pointer to a struct resource to fill in with reserved region
 *
 * This function allows drivers to lookup a node's 'memory-region' property
 * entries by index and return a struct resource for the entry.
 *
 * Returns 0 on success with @res filled in. Returns -ENODEV if 'memory-region'
 * is missing or unavailable, -EINVAL for any other error.
 */
int of_reserved_mem_region_to_resource(const struct device_node *np,
                                       unsigned int idx, struct resource *res)
{
        struct reserved_mem *rmem;

        if (!np)
                return -EINVAL;

        struct device_node *target __free(device_node) = of_parse_phandle(np, "memory-region", idx);
        if (!target || !of_device_is_available(target))
                return -ENODEV;

        rmem = of_reserved_mem_lookup(target);
        if (!rmem)
                return -EINVAL;

        resource_set_range(res, rmem->base, rmem->size);
        res->flags = IORESOURCE_MEM;
        res->name = rmem->name;
        return 0;
}
EXPORT_SYMBOL_GPL(of_reserved_mem_region_to_resource);

/**
 * of_reserved_mem_region_to_resource_byname() - Get a reserved memory region as a resource
 * @np:         node containing 'memory-region' property
 * @name:       name of 'memory-region' property entry to lookup
 * @res:        Pointer to a struct resource to fill in with reserved region
 *
 * This function allows drivers to lookup a node's 'memory-region' property
 * entries by name and return a struct resource for the entry.
 *
 * Returns 0 on success with @res filled in, or a negative error-code on
 * failure.
 */
int of_reserved_mem_region_to_resource_byname(const struct device_node *np,
                                              const char *name,
                                              struct resource *res)
{
        int idx;

        if (!name)
                return -EINVAL;

        idx = of_property_match_string(np, "memory-region-names", name);
        if (idx < 0)
                return idx;

        return of_reserved_mem_region_to_resource(np, idx, res);
}
EXPORT_SYMBOL_GPL(of_reserved_mem_region_to_resource_byname);

/**
 * of_reserved_mem_region_count() - Return the number of 'memory-region' entries
 * @np:         node containing 'memory-region' property
 *
 * This function allows drivers to retrieve the number of entries for a node's
 * 'memory-region' property.
 *
 * Returns the number of entries on success, or negative error code on a
 * malformed property.
 */
int of_reserved_mem_region_count(const struct device_node *np)
{
        return of_count_phandle_with_args(np, "memory-region", NULL);
}
EXPORT_SYMBOL_GPL(of_reserved_mem_region_count);