/*
   * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
   *
   * SPDX-License-Identifier:	GPL-2.0+
   */
  
  #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(const struct cbfs_cachenode *) ||
  				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_cachenode *);
  		newNode->name = (char *)fileHeader +
  				sizeof(struct cbfs_cachenode *);
  		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;
  }