/*
 * 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>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License or (at your optional) any later version of the license.
 */

#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>

#define MAX_RESERVED_REGIONS    16
static struct reserved_mem reserved_mem[MAX_RESERVED_REGIONS];
static int reserved_mem_count;

#if defined(CONFIG_HAVE_MEMBLOCK)
#include <linux/memblock.h>
int __init __weak 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;
        /*
         * We use __memblock_alloc_base() because memblock_alloc_base()
         * panic()s on allocation failure.
         */
        end = !end ? MEMBLOCK_ALLOC_ANYWHERE : end;
        base = __memblock_alloc_base(size, align, end);
        if (!base)
                return -ENOMEM;

        /*
         * Check if the allocated region fits in to start..end window
         */
        if (base < start) {
                memblock_free(base, size);
                return -ENOMEM;
        }

        *res_base = base;
        if (nomap)
                return memblock_remove(base, size);
        return 0;
}
#else
int __init __weak 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)
{
        pr_err("Reserved memory not supported, ignoring region 0x%llx%s\n",
                  size, nomap ? " (nomap)" : "");
        return -ENOSYS;
}
#endif

/**
 * res_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 all defined regions.\n");
                return;
        }

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

        reserved_mem_count++;
        return;
}

/**
 * res_mem_alloc_size() - allocate reserved memory described by 'size', 'align'
 *                        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;
        int 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);

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

        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);
        }

        /* 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)
            && !of_get_flat_dt_prop(node, "no-map", NULL)) {
                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 %ld 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 %ld 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);

/**
 * res_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;

        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;

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

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;

        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 && next->base))
                        continue;
                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;

                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)
                        __reserved_mem_init_node(rmem);
        }
}

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;

        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_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;
        struct reserved_mem *rmem = NULL;

        mutex_lock(&of_rmem_assigned_device_mutex);
        list_for_each_entry(rd, &of_rmem_assigned_device_list, list) {
                if (rd->dev == dev) {
                        rmem = rd->rmem;
                        list_del(&rd->list);
                        kfree(rd);
                        break;
                }
        }
        mutex_unlock(&of_rmem_assigned_device_mutex);

        if (!rmem || !rmem->ops || !rmem->ops->device_release)
                return;

        rmem->ops->device_release(rmem, dev);
}
EXPORT_SYMBOL_GPL(of_reserved_mem_device_release);