// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
 */

#include <common.h>
#include <cbfs.h>
#include <malloc.h>
#include <asm/byteorder.h>

static const u32 good_magic = 0x4f524243;
static const u8 good_file_magic[] = "LARCHIVE";

struct cbfs_priv {
        int initialized;
        struct cbfs_header header;
        struct cbfs_cachenode *file_cache;
        enum cbfs_result result;
};

static struct cbfs_priv cbfs_s;

const char *file_cbfs_error(void)
{
        switch (cbfs_s.result) {
        case CBFS_SUCCESS:
                return "Success";
        case CBFS_NOT_INITIALIZED:
                return "CBFS not initialized";
        case CBFS_BAD_HEADER:
                return "Bad CBFS header";
        case CBFS_BAD_FILE:
                return "Bad CBFS file";
        case CBFS_FILE_NOT_FOUND:
                return "File not found";
        default:
                return "Unknown";
        }
}

enum cbfs_result cbfs_get_result(void)
{
        return cbfs_s.result;
}

/* Do endian conversion on the CBFS header structure. */
static void swap_header(struct cbfs_header *dest, struct cbfs_header *src)
{
        dest->magic = be32_to_cpu(src->magic);
        dest->version = be32_to_cpu(src->version);
        dest->rom_size = be32_to_cpu(src->rom_size);
        dest->boot_block_size = be32_to_cpu(src->boot_block_size);
        dest->align = be32_to_cpu(src->align);
        dest->offset = be32_to_cpu(src->offset);
}

/* Do endian conversion on a CBFS file header. */
static void swap_file_header(struct cbfs_fileheader *dest,
                             const struct cbfs_fileheader *src)
{
        memcpy(&dest->magic, &src->magic, sizeof(dest->magic));
        dest->len = be32_to_cpu(src->len);
        dest->type = be32_to_cpu(src->type);
        dest->attributes_offset = be32_to_cpu(src->attributes_offset);
        dest->offset = be32_to_cpu(src->offset);
}

/*
 * Given a starting position in memory, scan forward, bounded by a size, and
 * find the next valid CBFS file. No memory is allocated by this function. The
 * caller is responsible for allocating space for the new file structure.
 *
 * @param start         The location in memory to start from.
 * @param size          The size of the memory region to search.
 * @param align         The alignment boundaries to check on.
 * @param new_node      A pointer to the file structure to load.
 * @param used          A pointer to the count of of bytes scanned through,
 *                      including the file if one is found.
 *
 * @return 1 if a file is found, 0 if one isn't.
 */
static int file_cbfs_next_file(struct cbfs_priv *priv, u8 *start, u32 size,
                               u32 align, struct cbfs_cachenode *new_node,
                               u32 *used)
{
        struct cbfs_fileheader header;

        *used = 0;

        while (size >= align) {
                const struct cbfs_fileheader *file_header =
                        (const struct cbfs_fileheader *)start;
                u32 name_len;
                u32 step;

                /* Check if there's a file here. */
                if (memcmp(good_file_magic, &file_header->magic,
                           sizeof(file_header->magic))) {
                        *used += align;
                        size -= align;
                        start += align;
                        continue;
                }

                swap_file_header(&header, file_header);
                if (header.offset < sizeof(struct cbfs_fileheader)) {
                        priv->result = CBFS_BAD_FILE;
                        return -1;
                }
                new_node->next = NULL;
                new_node->type = header.type;
                new_node->data = start + header.offset;
                new_node->data_length = header.len;
                name_len = header.offset - sizeof(struct cbfs_fileheader);
                new_node->name = (char *)file_header +
                                sizeof(struct cbfs_fileheader);
                new_node->name_length = name_len;
                new_node->attributes_offset = header.attributes_offset;

                step = header.len;
                if (step % align)
                        step = step + align - step % align;

                *used += step;
                return 1;
        }
        return 0;
}

/* Look through a CBFS instance and copy file metadata into regular memory. */
static void file_cbfs_fill_cache(struct cbfs_priv *priv, u8 *start, u32 size,
                                 u32 align)
{
        struct cbfs_cachenode *cache_node;
        struct cbfs_cachenode *new_node;
        struct cbfs_cachenode **cache_tail = &priv->file_cache;

        /* Clear out old information. */
        cache_node = priv->file_cache;
        while (cache_node) {
                struct cbfs_cachenode *old_node = cache_node;
                cache_node = cache_node->next;
                free(old_node);
        }
        priv->file_cache = NULL;

        while (size >= align) {
                int result;
                u32 used;

                new_node = (struct cbfs_cachenode *)
                                malloc(sizeof(struct cbfs_cachenode));
                result = file_cbfs_next_file(priv, start, size, align, new_node,
                                             &used);

                if (result < 0) {
                        free(new_node);
                        return;
                } else if (result == 0) {
                        free(new_node);
                        break;
                }
                *cache_tail = new_node;
                cache_tail = &new_node->next;

                size -= used;
                start += used;
        }
        priv->result = CBFS_SUCCESS;
}

/* Get the CBFS header out of the ROM and do endian conversion. */
static int file_cbfs_load_header(uintptr_t end_of_rom,
                                 struct cbfs_header *header)
{
        struct cbfs_header *header_in_rom;
        int32_t offset = *(u32 *)(end_of_rom - 3);

        header_in_rom = (struct cbfs_header *)(end_of_rom + offset + 1);
        swap_header(header, header_in_rom);

        if (header->magic != good_magic || header->offset >
                        header->rom_size - header->boot_block_size) {
                cbfs_s.result = CBFS_BAD_HEADER;
                return 1;
        }
        return 0;
}

static int cbfs_load_header_ptr(struct cbfs_priv *priv, ulong base,
                                struct cbfs_header *header)
{
        struct cbfs_header *header_in_rom;

        header_in_rom = (struct cbfs_header *)base;
        swap_header(header, header_in_rom);

        if (header->magic != good_magic || header->offset >
                        header->rom_size - header->boot_block_size) {
                priv->result = CBFS_BAD_HEADER;
                return -EFAULT;
        }

        return 0;
}

static void cbfs_init(struct cbfs_priv *priv, uintptr_t end_of_rom)
{
        u8 *start_of_rom;

        priv->initialized = 0;

        if (file_cbfs_load_header(end_of_rom, &priv->header))
                return;

        start_of_rom = (u8 *)(end_of_rom + 1 - priv->header.rom_size);

        file_cbfs_fill_cache(priv, start_of_rom, priv->header.rom_size,
                             priv->header.align);
        if (priv->result == CBFS_SUCCESS)
                priv->initialized = 1;
}

void file_cbfs_init(uintptr_t end_of_rom)
{
        cbfs_init(&cbfs_s, end_of_rom);
}

int cbfs_init_mem(ulong base, ulong size, struct cbfs_priv **privp)
{
        struct cbfs_priv priv_s, *priv = &priv_s;
        int ret;

        /*
         * Use a local variable to start with until we know that the CBFS is
         * valid. Assume that a master header appears at the start, at offset
         * 0x38.
         */
        ret = cbfs_load_header_ptr(priv, base + 0x38, &priv->header);
        if (ret)
                return ret;

        file_cbfs_fill_cache(priv, (u8 *)base, priv->header.rom_size,
                             priv->header.align);
        if (priv->result != CBFS_SUCCESS)
                return -EINVAL;

        priv->initialized = 1;
        priv = malloc(sizeof(priv_s));
        if (!priv)
                return -ENOMEM;
        memcpy(priv, &priv_s, sizeof(priv_s));
        *privp = priv;

        return 0;
}

const struct cbfs_header *file_cbfs_get_header(void)
{
        struct cbfs_priv *priv = &cbfs_s;

        if (priv->initialized) {
                priv->result = CBFS_SUCCESS;
                return &priv->header;
        } else {
                priv->result = CBFS_NOT_INITIALIZED;
                return NULL;
        }
}

const struct cbfs_cachenode *file_cbfs_get_first(void)
{
        struct cbfs_priv *priv = &cbfs_s;

        if (!priv->initialized) {
                priv->result = CBFS_NOT_INITIALIZED;
                return NULL;
        } else {
                priv->result = CBFS_SUCCESS;
                return priv->file_cache;
        }
}

void file_cbfs_get_next(const struct cbfs_cachenode **file)
{
        struct cbfs_priv *priv = &cbfs_s;

        if (!priv->initialized) {
                priv->result = CBFS_NOT_INITIALIZED;
                *file = NULL;
                return;
        }

        if (*file)
                *file = (*file)->next;
        priv->result = CBFS_SUCCESS;
}

const struct cbfs_cachenode *cbfs_find_file(struct cbfs_priv *priv,
                                            const char *name)
{
        struct cbfs_cachenode *cache_node = priv->file_cache;

        if (!priv->initialized) {
                priv->result = CBFS_NOT_INITIALIZED;
                return NULL;
        }

        while (cache_node) {
                if (!strcmp(name, cache_node->name))
                        break;
                cache_node = cache_node->next;
        }
        if (!cache_node)
                priv->result = CBFS_FILE_NOT_FOUND;
        else
                priv->result = CBFS_SUCCESS;

        return cache_node;
}

const struct cbfs_cachenode *file_cbfs_find(const char *name)
{
        return cbfs_find_file(&cbfs_s, name);
}

const struct cbfs_cachenode *file_cbfs_find_uncached(uintptr_t end_of_rom,
                                                     const char *name)
{
        struct cbfs_priv *priv = &cbfs_s;
        u8 *start;
        u32 size;
        u32 align;
        static struct cbfs_cachenode node;

        if (file_cbfs_load_header(end_of_rom, &priv->header))
                return NULL;

        start = (u8 *)(end_of_rom + 1 - priv->header.rom_size);
        size = priv->header.rom_size;
        align = priv->header.align;

        while (size >= align) {
                int result;
                u32 used;

                result = file_cbfs_next_file(priv, start, size, align, &node,
                                             &used);

                if (result < 0)
                        return NULL;
                else if (result == 0)
                        break;

                if (!strcmp(name, node.name))
                        return &node;

                size -= used;
                start += used;
        }
        cbfs_s.result = CBFS_FILE_NOT_FOUND;
        return NULL;
}

const char *file_cbfs_name(const struct cbfs_cachenode *file)
{
        cbfs_s.result = CBFS_SUCCESS;

        return file->name;
}

u32 file_cbfs_size(const struct cbfs_cachenode *file)
{
        cbfs_s.result = CBFS_SUCCESS;

        return file->data_length;
}

u32 file_cbfs_type(const struct cbfs_cachenode *file)
{
        cbfs_s.result = CBFS_SUCCESS;

        return file->type;
}

long file_cbfs_read(const struct cbfs_cachenode *file, void *buffer,
                    unsigned long maxsize)
{
        u32 size;

        size = file->data_length;
        if (maxsize && size > maxsize)
                size = maxsize;

        memcpy(buffer, file->data, size);
        cbfs_s.result = CBFS_SUCCESS;

        return size;
}