@@ -320,6 +320,7 @@ static struct mtd_part *add_one_partition(struct mtd_info *master,
u_int32_t cur_offset)
{
struct mtd_part *slave;
+ unsigned offset_checked = 0;
/* allocate the partition structure */
slave = kzalloc(sizeof(*slave), GFP_KERNEL);
@@ -436,6 +437,20 @@ static struct mtd_part *add_one_partition(struct mtd_info *master,
/* The loop searched for the region _behind_ the first one */
i--;
+ if (slave->mtd.flags & MTD_WRITEABLE) {
+ /* A region starts on boundary of it's erase size.
+ * Partition offset within region must align
+ * on region's erase size
+ */
+ if ((slave->offset - regions[i].offset) % regions[i].erasesize) {
+ slave->mtd.flags &= ~MTD_WRITEABLE;
+ printk(KERN_WARNING"mtd: partition \"%s\" doesn't start on an "
+ "erase block boundary -- force read-only\n", part->name);
+ } else
+ /* Skip offset check below */
+ offset_checked = 1;
+ }
+
/* Pick biggest erasesize */
for (; i < max && regions[i].offset < end; i++) {
if (slave->mtd.erasesize < regions[i].erasesize) {
@@ -448,7 +463,7 @@ static struct mtd_part *add_one_partition(struct mtd_info *master,
slave->mtd.erasesize = master->erasesize;
}
- if ((slave->mtd.flags & MTD_WRITEABLE) &&
+ if (!offset_checked && (slave->mtd.flags & MTD_WRITEABLE) &&
(slave->offset % slave->mtd.erasesize)) {
/* Doesn't start on a boundary of major erase size */
/* FIXME: Let it be writable if it is on a boundary of
Hi, Currently add_one_partition in mtdpart.c does not handle erase regions with odd number of blocks well. Some scenarios are : 1. Region 0 has 3 blocks of 256KB. Region 1 has 512KB blocks. Partiton starting at offset 256KB and size 1MB turns read only. 2. Region 0 has 3 blocks of 256KB. Region 1 has 512KB blocks. All partitions created on region 2 turn read only. Every partition start offset should be multiple of partition erase size. It is this condition which causes valid partitions to turn read-only. The following patch is an attempt to allow such regions. Is such a change to MTD core correct / acceptable? Any suggestions are much appreciated. Signed-off-by: Rohit Hagargundgi <h.rohit@samsung.com> --- mtdpart.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) ---