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

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

enum cbfs_result file_cbfs_result;

const char *file_cbfs_error(void)
{
        switch (file_cbfs_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";
        }
}


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


static int initialized;
static struct cbfs_header cbfs_header;
static struct cbfs_cachenode *file_cache;

/* 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->checksum = be32_to_cpu(src->checksum);
        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 newNode       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(u8 *start, u32 size, u32 align,
                               struct cbfs_cachenode *newNode, u32 *used)
{
        struct cbfs_fileheader header;

        *used = 0;

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

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

                swap_file_header(&header, fileHeader);
                if (header.offset < sizeof(struct cbfs_fileheader) ||
                    header.offset > header.len) {
                        file_cbfs_result = CBFS_BAD_FILE;
                        return -1;
                }
                newNode->next = NULL;
                newNode->type = header.type;
                newNode->data = start + header.offset;
                newNode->data_length = header.len;
                name_len = header.offset - sizeof(struct cbfs_fileheader);
                newNode->name = (char *)fileHeader +
                                sizeof(struct cbfs_fileheader);
                newNode->name_length = name_len;
                newNode->checksum = header.checksum;

                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(u8 *start, u32 size, u32 align)
{
        struct cbfs_cachenode *cache_node;
        struct cbfs_cachenode *newNode;
        struct cbfs_cachenode **cache_tail = &file_cache;

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

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

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

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

                size -= used;
                start += used;
        }
        file_cbfs_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;

        header_in_rom = (struct cbfs_header *)(uintptr_t)
                        *(u32 *)(end_of_rom - 3);
        swap_header(header, header_in_rom);

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

void file_cbfs_init(uintptr_t end_of_rom)
{
        u8 *start_of_rom;
        initialized = 0;

        if (file_cbfs_load_header(end_of_rom, &cbfs_header))
                return;

        start_of_rom = (u8 *)(end_of_rom + 1 - cbfs_header.rom_size);

        file_cbfs_fill_cache(start_of_rom + cbfs_header.offset,
                             cbfs_header.rom_size, cbfs_header.align);
        if (file_cbfs_result == CBFS_SUCCESS)
                initialized = 1;
}

const struct cbfs_header *file_cbfs_get_header(void)
{
        if (initialized) {
                file_cbfs_result = CBFS_SUCCESS;
                return &cbfs_header;
        } else {
                file_cbfs_result = CBFS_NOT_INITIALIZED;
                return NULL;
        }
}

const struct cbfs_cachenode *file_cbfs_get_first(void)
{
        if (!initialized) {
                file_cbfs_result = CBFS_NOT_INITIALIZED;
                return NULL;
        } else {
                file_cbfs_result = CBFS_SUCCESS;
                return file_cache;
        }
}

void file_cbfs_get_next(const struct cbfs_cachenode **file)
{
        if (!initialized) {
                file_cbfs_result = CBFS_NOT_INITIALIZED;
                file = NULL;
                return;
        }

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

const struct cbfs_cachenode *file_cbfs_find(const char *name)
{
        struct cbfs_cachenode *cache_node = file_cache;

        if (!initialized) {
                file_cbfs_result = CBFS_NOT_INITIALIZED;
                return NULL;
        }

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

        return cache_node;
}

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

        if (file_cbfs_load_header(end_of_rom, &cbfs_header))
                return NULL;

        start = (u8 *)(end_of_rom + 1 - cbfs_header.rom_size);
        size = cbfs_header.rom_size;
        align = cbfs_header.align;

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

                result = file_cbfs_next_file(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;
        }
        file_cbfs_result = CBFS_FILE_NOT_FOUND;
        return NULL;
}

const char *file_cbfs_name(const struct cbfs_cachenode *file)
{
        file_cbfs_result = CBFS_SUCCESS;
        return file->name;
}

u32 file_cbfs_size(const struct cbfs_cachenode *file)
{
        file_cbfs_result = CBFS_SUCCESS;
        return file->data_length;
}

u32 file_cbfs_type(const struct cbfs_cachenode *file)
{
        file_cbfs_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);

        file_cbfs_result = CBFS_SUCCESS;
        return size;
}