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gpt: gpt_load_table_from_partition: fix off-by-one error for num_sectors

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When using first_lba and last_lba information from the GPT entry to
calculate the number of sectors, we need to add 1 to the result.

Imagine if both values were 1.  This means there is 1 sector of data
and the first and last LBA values are same.  However, the current
calculation is: num_sectors = last_lba - first_lba.

In this case, it would return a value of 0.  (Always 1 less sector
than it should).

Tested on the CDT partition of RB3 Gen2:
In the rawprogram3.xml file it has num_partition_sectors="32"
(4096 byte sector size).  This should result in a binary size of
131072.

Pre-patch:
$ qdl --storage ufs prog_firehose_ddr.elf read 3/cdt cdt-bad.bin
waiting for programmer...
partition 6 has not GPT header
partition 7 has not GPT header
0 patches applied
read "cdt-bad.bin" successfully
$ ls -l cdt-bad.bin
-rw-r--r-- 1 user user 126976 Sep 16 21:02 cdt-bad.bin

Post-patch:
$ qdl --storage ufs prog_firehose_ddr.elf read 3/cdt cdt-good.bin
Waiting for EDL device
waiting for programmer...
partition 6 has not GPT header
partition 7 has not GPT header
0 patches applied
read "cdt-good.bin" successfully
$ ls -l cdt-good.bin
-rw-r--r-- 1 user user 131072 Sep 16 21:04 cdt-good.bin

Signed-off-by: Michael Scott <mike.scott@oss.qualcomm.com>
This commit is contained in:
Michael Scott
2025-09-16 20:48:47 -07:00
committed by Bjorn Andersson
parent 1b9974c198
commit f3b4fd4fdc
1 changed files with 4 additions and 3 deletions
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7
gpt.c
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@@ -201,10 +201,11 @@ static int gpt_load_table_from_partition(struct qdl_device *qdl, unsigned int ph
partition->name = strdup(name);
partition->partition = phys_partition;
partition->start_sector = entry->first_lba;
partition->num_sectors = entry->last_lba - entry->first_lba;
/* if first_lba == last_lba there is 1 sector worth of data (IE: add 1 below) */
partition->num_sectors = entry->last_lba - entry->first_lba + 1;
ux_debug(" %3d: %s sector %u to %u\n", i, partition->name,
partition->start_sector, partition->start_sector + partition->num_sectors);
ux_debug(" %3d: %s start sector %u, num sectors %u\n", i, partition->name,
partition->start_sector, partition->num_sectors);
if (gpt_partitions) {
gpt_partitions_last->next = partition;