text: // SPDX-License-Identifier: GPL-2.0
  /*
   *  fs/partitions/amiga.c
   *
   *  Code extracted from drivers/block/genhd.c
   *
   *  Copyright (C) 1991-1998  Linus Torvalds
   *  Re-organised Feb 1998 Russell King
   */
  
  #define pr_fmt(fmt) fmt
  
  #include <linux/types.h>
  #include <linux/affs_hardblocks.h>
  
  #include "check.h"
  #include "amiga.h"
  
  static __inline__ u32
  checksum_block(__be32 *m, int size)
  {
  	u32 sum = 0;
  
  	while (size--)
  		sum += be32_to_cpu(*m++);
  	return sum;
  }
  
  int amiga_partition(struct parsed_partitions *state)
  {
  	Sector sect;
  	unsigned char *data;
  	struct RigidDiskBlock *rdb;
  	struct PartitionBlock *pb;
  	int start_sect, nr_sects, blk, part, res = 0;
  	int blksize = 1;	/* Multiplier for disk block size */
  	int slot = 1;
  	char b[BDEVNAME_SIZE];
  
  	for (blk = 0; ; blk++, put_dev_sector(sect)) {
  		if (blk == RDB_ALLOCATION_LIMIT)
  			goto rdb_done;
  		data = read_part_sector(state, blk, &sect);
  		if (!data) {
  			if (warn_no_part)
  				pr_err("Dev %s: unable to read RDB block %d\n",
  				       bdevname(state->bdev, b), blk);
  			res = -1;
  			goto rdb_done;
  		}
  		if (*(__be32 *)data != cpu_to_be32(IDNAME_RIGIDDISK))
  			continue;
  
  		rdb = (struct RigidDiskBlock *)data;
  		if (checksum_block((__be32 *)data, be32_to_cpu(rdb->rdb_SummedLongs) & 0x7F) == 0)
  			break;
  		/* Try again with 0xdc..0xdf zeroed, Windows might have
  		 * trashed it.
  		 */
  		*(__be32 *)(data+0xdc) = 0;
  		if (checksum_block((__be32 *)data,
  				be32_to_cpu(rdb->rdb_SummedLongs) & 0x7F)==0) {
  			pr_err("Trashed word at 0xd0 in block %d ignored in checksum calculation\n",
  			       blk);
  			break;
  		}
  
  		pr_err("Dev %s: RDB in block %d has bad checksum\n",
  		       bdevname(state->bdev, b), blk);
  	}
  
  	/* blksize is blocks per 512 byte standard block */
  	blksize = be32_to_cpu( rdb->rdb_BlockBytes ) / 512;
  
  	{
  		char tmp[7 + 10 + 1 + 1];
  
  		/* Be more informative */
  		snprintf(tmp, sizeof(tmp), " RDSK (%d)", blksize * 512);
  		strlcat(state->pp_buf, tmp, PAGE_SIZE);
  	}
  	blk = be32_to_cpu(rdb->rdb_PartitionList);
  	put_dev_sector(sect);
  	for (part = 1; blk>0 && part<=16; part++, put_dev_sector(sect)) {
  		blk *= blksize;	/* Read in terms partition table understands */
  		data = read_part_sector(state, blk, &sect);
  		if (!data) {
  			if (warn_no_part)
  				pr_err("Dev %s: unable to read partition block %d\n",
  				       bdevname(state->bdev, b), blk);
  			res = -1;
  			goto rdb_done;
  		}
  		pb  = (struct PartitionBlock *)data;
  		blk = be32_to_cpu(pb->pb_Next);
  		if (pb->pb_ID != cpu_to_be32(IDNAME_PARTITION))
  			continue;
  		if (checksum_block((__be32 *)pb, be32_to_cpu(pb->pb_SummedLongs) & 0x7F) != 0 )
  			continue;
  
  		/* Tell Kernel about it */
  
  		nr_sects = (be32_to_cpu(pb->pb_Environment[10]) + 1 -
  			    be32_to_cpu(pb->pb_Environment[9])) *
  			   be32_to_cpu(pb->pb_Environment[3]) *
  			   be32_to_cpu(pb->pb_Environment[5]) *
  			   blksize;
  		if (!nr_sects)
  			continue;
  		start_sect = be32_to_cpu(pb->pb_Environment[9]) *
  			     be32_to_cpu(pb->pb_Environment[3]) *
  			     be32_to_cpu(pb->pb_Environment[5]) *
  			     blksize;
  		put_partition(state,slot++,start_sect,nr_sects);
  		{
  			/* Be even more informative to aid mounting */
  			char dostype[4];
  			char tmp[42];
  
  			__be32 *dt = (__be32 *)dostype;
  			*dt = pb->pb_Environment[16];
  			if (dostype[3] < ' ')
  				snprintf(tmp, sizeof(tmp), " (%c%c%c^%c)",
  					dostype[0], dostype[1],
  					dostype[2], dostype[3] + '@' );
  			else
  				snprintf(tmp, sizeof(tmp), " (%c%c%c%c)",
  					dostype[0], dostype[1],
  					dostype[2], dostype[3]);
  			strlcat(state->pp_buf, tmp, PAGE_SIZE);
  			snprintf(tmp, sizeof(tmp), "(res %d spb %d)",
  				be32_to_cpu(pb->pb_Environment[6]),
  				be32_to_cpu(pb->pb_Environment[4]));
  			strlcat(state->pp_buf, tmp, PAGE_SIZE);
  		}
  		res = 1;
  	}
  	strlcat(state->pp_buf, "\n", PAGE_SIZE);
  
  rdb_done:
  	return res;
  }
  