/*
   *
   *	based on code of fs/reiserfs/dev.c by
   *
   *	(C) Copyright 2003 - 2004
   *	Sysgo AG, <www.elinos.com>, Pavel Bartusek <pba@sysgo.com>
   *

   * SPDX-License-Identifier:	GPL-2.0+

   */
  
  
  #include <common.h>
  #include <config.h>
  #include <zfs_common.h>
  
  static block_dev_desc_t *zfs_block_dev_desc;

  static disk_partition_t *part_info;

  void zfs_set_blk_dev(block_dev_desc_t *rbdd, disk_partition_t *info)

  {
  	zfs_block_dev_desc = rbdd;

  	part_info = info;

  }
  
  /* err */
  int zfs_devread(int sector, int byte_offset, int byte_len, char *buf)
  {
  	short sec_buffer[SECTOR_SIZE/sizeof(short)];
  	char *sec_buf = (char *)sec_buffer;
  	unsigned block_len;
  
  	/*
  	 *	Check partition boundaries
  	 */
  	if ((sector < 0) ||
  		((sector + ((byte_offset + byte_len - 1) >> SECTOR_BITS)) >=

  		 part_info->size)) {

  		/*		errnum = ERR_OUTSIDE_PART; */
  		printf(" ** zfs_devread() read outside partition sector %d
  ", sector);
  		return 1;
  	}
  
  	/*
  	 *	Get the read to the beginning of a partition.
  	 */
  	sector += byte_offset >> SECTOR_BITS;
  	byte_offset &= SECTOR_SIZE - 1;
  
  	debug(" <%d, %d, %d>
  ", sector, byte_offset, byte_len);
  
  	if (zfs_block_dev_desc == NULL) {
  		printf("** Invalid Block Device Descriptor (NULL)
  ");
  		return 1;
  	}
  
  	if (byte_offset != 0) {
  		/* read first part which isn't aligned with start of sector */
  		if (zfs_block_dev_desc->block_read(zfs_block_dev_desc->dev,

  			part_info->start + sector, 1,
  			(unsigned long *)sec_buf) != 1) {

  			printf(" ** zfs_devread() read error **
  ");
  			return 1;
  		}
  		memcpy(buf, sec_buf + byte_offset,
  			   min(SECTOR_SIZE - byte_offset, byte_len));
  		buf += min(SECTOR_SIZE - byte_offset, byte_len);
  		byte_len -= min(SECTOR_SIZE - byte_offset, byte_len);
  		sector++;
  	}
  
  	if (byte_len == 0)
  		return 0;
  
  	/*	read sector aligned part */
  	block_len = byte_len & ~(SECTOR_SIZE - 1);
  
  	if (block_len == 0) {
  		u8 p[SECTOR_SIZE];
  
  		block_len = SECTOR_SIZE;
  		zfs_block_dev_desc->block_read(zfs_block_dev_desc->dev,

  			part_info->start + sector,
  			1, (unsigned long *)p);

  		memcpy(buf, p, byte_len);
  		return 0;
  	}
  
  	if (zfs_block_dev_desc->block_read(zfs_block_dev_desc->dev,

  		part_info->start + sector, block_len / SECTOR_SIZE,
  		(unsigned long *) buf) != block_len / SECTOR_SIZE) {

  		printf(" ** zfs_devread() read error - block
  ");
  		return 1;
  	}
  
  	block_len = byte_len & ~(SECTOR_SIZE - 1);
  	buf += block_len;
  	byte_len -= block_len;
  	sector += block_len / SECTOR_SIZE;
  
  	if (byte_len != 0) {
  		/* read rest of data which are not in whole sector */
  		if (zfs_block_dev_desc->
  			block_read(zfs_block_dev_desc->dev,

  					   part_info->start + sector, 1,

  					   (unsigned long *) sec_buf) != 1) {
  			printf(" ** zfs_devread() read error - last part
  ");
  			return 1;
  		}
  		memcpy(buf, sec_buf, byte_len);
  	}
  	return 0;
  }