[U-Boot] [PATCH v6 05/18] disk: part: compute partition_entry_lba

[Patrick Delaunay]

the value for partition_entry_lba of secondary GPT (last usable lba + 1)
is not correct with MTD support as last usable LBA need to be erase size
aligned

The correct location of partition entry is always recomputed with
the formula :
partition_entry_lba =
   alternate_lba -
   num_pte * sizeof_partition_entry / lba_size

Signed-off-by: Patrick Delaunay <patrick.delaunay at st.com>
Reviewed-by: Christophe KERELLO <christophe.kerello at st.com>
Reviewed-by: Simon Glass <sjg at chromium.org>
---
the device mapping is

1/ for block case:

  last_usable_lba     -> partition_entry_lba - 1
  partition_entry_lba ->  PTE table (num * sizeof(PTE))
  alternate_lba       ->  secondary GPT
  -> end of device

2/ for MTD case : end of the last good block

  -------------

  last_usable_lba     -> last good erase block - 1
  -------------erase BLOCK aligned
  XXXXXXXXXXXXXXXXXX  -> skipped LBA for MTD case
  partition_entry_lba ->  PTE table (num * sizeof(PTE))
  alternate_lba       ->  secondary GPT
  -------------erase BLOCK aligned
  xxxxx skipping bad block
  ->end of device

Changes in v6:
- add comment for function prepare_backup_gpt_header

Changes in v5: None
Changes in v4: None
Changes in v3: None
Changes in v2: None

 disk/part_efi.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/disk/part_efi.c b/disk/part_efi.c
index 181a748..23a582a 100644
--- a/disk/part_efi.c
+++ b/disk/part_efi.c
@@ -155,7 +155,14 @@ static int validate_gpt_entries(gpt_header *gpt_h, gpt_entry *gpt_e)
 	return 0;
 }
 
-static void prepare_backup_gpt_header(gpt_header *gpt_h)
+/*
+ * prepare_backup_gpt_header() - change primary GPT header to backup GPT header
+ *
+ * @param gpt_h - pointer to GPT header (in=primary, out=secondary)
+ * @param pte_blk_cnt - number of block for size of partition entry array (PTE)
+ */
+static void prepare_backup_gpt_header(gpt_header *gpt_h,
+				      const int pte_blk_cnt)
 {
 	uint32_t calc_crc32;
 	uint64_t val;
@@ -164,8 +171,7 @@ static void prepare_backup_gpt_header(gpt_header *gpt_h)
 	val = le64_to_cpu(gpt_h->alternate_lba);
 	gpt_h->alternate_lba = gpt_h->my_lba;
 	gpt_h->my_lba = cpu_to_le64(val);
-	gpt_h->partition_entry_lba =
-			cpu_to_le64(le64_to_cpu(gpt_h->last_usable_lba) + 1);
+	gpt_h->partition_entry_lba = cpu_to_le64(val - pte_blk_cnt);
 	gpt_h->header_crc32 = 0;
 
 	calc_crc32 = efi_crc32((const unsigned char *)gpt_h,
@@ -409,7 +415,7 @@ int write_gpt_table(struct blk_desc *dev_desc,
 		       pte_blk_cnt, gpt_e) != pte_blk_cnt)
 		goto err;
 
-	prepare_backup_gpt_header(gpt_h);
+	prepare_backup_gpt_header(gpt_h, pte_blk_cnt);
 
 	if (blk_dwrite(dev_desc, (lbaint_t)le64_to_cpu(gpt_h->last_usable_lba)
 		       + 1, pte_blk_cnt, gpt_e) != pte_blk_cnt)
@@ -824,7 +830,7 @@ int write_mbr_and_gpt_partitions(struct blk_desc *dev_desc, void *buf)
 		return 1;
 	}
 
-	prepare_backup_gpt_header(gpt_h);
+	prepare_backup_gpt_header(gpt_h, gpt_e_blk_cnt);
 
 	/* write Backup GPT */
 	lba = le64_to_cpu(gpt_h->partition_entry_lba);
-- 
1.9.1