// 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/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 "of_private.h"

#define MAX_RESERVED_REGIONS    64
static struct reserved_mem reserved_mem[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;

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

        *res_base = base;
        if (nomap)
                return memblock_mark_nomap(base, size);

        return memblock_reserve(base, size);
}

/*
 * fdt_reserved_mem_save_node() - save fdt node for second pass initialization
 */
void __init fdt_reserved_mem_save_node(unsigned long node, const char *uname,
                                      phys_addr_t base, phys_addr_t size)
{
        struct reserved_mem *rmem = &reserved_mem[reserved_mem_count];

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

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

        reserved_mem_count++;
        return;
}

/*
 * __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 *res_base, phys_addr_t *res_size)
{
        int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
        phys_addr_t start = 0, end = 0;
        phys_addr_t base = 0, align = 0, size;
        int 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;

        /* Need adjust the alignment to satisfy the CMA requirement */
        if (IS_ENABLED(CONFIG_CMA)
            && of_flat_dt_is_compatible(node, "shared-dma-pool")
            && of_get_flat_dt_prop(node, "reusable", NULL)
            && !nomap) {
                unsigned long order =
                        max_t(unsigned long, MAX_ORDER - 1, pageblock_order);

                align = max(align, (phys_addr_t)PAGE_SIZE << order);
        }

        prop = of_get_flat_dt_prop(node, "alloc-ranges", &len);
        if (prop) {

                if (len % t_len != 0) {
                        pr_err("invalid alloc-ranges property in '%s', skipping node.\n",
                               uname);
                        return -EINVAL;
                }

                base = 0;

                while (len > 0) {
                        start = dt_mem_next_cell(dt_root_addr_cells, &prop);
                        end = start + dt_mem_next_cell(dt_root_size_cells,
                                                       &prop);

                        ret = early_init_dt_alloc_reserved_memory_arch(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;
                        }
                        len -= t_len;
                }

        } 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_info("failed to allocate memory for node '%s'\n", uname);
                return -ENOMEM;
        }

        *res_base = base;
        *res_size = size;

        return 0;
}

static const struct of_device_id __rmem_of_table_sentinel
        __used __section("__reservedmem_of_table_end");

/*
 * __reserved_mem_init_node() - call region specific reserved memory init code
 */
static int __init __reserved_mem_init_node(struct reserved_mem *rmem)
{
        extern const struct of_device_id __reservedmem_of_table[];
        const struct of_device_id *i;
        int ret = -ENOENT;

        for (i = __reservedmem_of_table; i < &__rmem_of_table_sentinel; i++) {
                reservedmem_of_init_fn initfn = i->data;
                const char *compat = i->compatible;

                if (!of_flat_dt_is_compatible(rmem->fdt_node, compat))
                        continue;

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

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_init_reserved_mem() - allocate and init all saved reserved memory regions
 */
void __init fdt_init_reserved_mem(void)
{
        int i;

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

        for (i = 0; i < reserved_mem_count; i++) {
                struct reserved_mem *rmem = &reserved_mem[i];
                unsigned long node = rmem->fdt_node;
                int len;
                const __be32 *prop;
                int err = 0;
                bool nomap;

                nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
                prop = of_get_flat_dt_prop(node, "phandle", &len);
                if (!prop)
                        prop = of_get_flat_dt_prop(node, "linux,phandle", &len);
                if (prop)
                        rmem->phandle = of_read_number(prop, len/4);

                if (rmem->size == 0)
                        err = __reserved_mem_alloc_size(node, rmem->name,
                                                 &rmem->base, &rmem->size);
                if (err == 0) {
                        err = __reserved_mem_init_node(rmem);
                        if (err != 0 && err != -ENOENT) {
                                pr_info("node %s compatible matching fail\n",
                                        rmem->name);
                                if (nomap)
                                        memblock_clear_nomap(rmem->base, rmem->size);
                                else
                                        memblock_free(rmem->base, rmem->size);
                        }
                }
        }
}

static inline struct reserved_mem *__find_rmem(struct device_node *node)
{
        unsigned int i;

        if (!node->phandle)
                return NULL;

        for (i = 0; i < reserved_mem_count; i++)
                if (reserved_mem[i].phandle == node->phandle)
                        return &reserved_mem[i];
        return NULL;
}

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 = __find_rmem(target);
        of_node_put(target);

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

        rd = kmalloc(sizeof(struct rmem_assigned_device), GFP_KERNEL);
        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 (!strcmp(reserved_mem[i].name, name))
                        return &reserved_mem[i];

        return NULL;
}
EXPORT_SYMBOL_GPL(of_reserved_mem_lookup);