[U-Boot] [PATCH] [nand] Implement nand_extent_skip_bad

Pantelis Antoniou
2012-12-10T15:24:24Z

When accessing nand any bad blocks encountered are skipped, with no
indication about the amount of bad blocks encountered.
While this is normally fine, when you have to write a large amount
of data in chunks, you need to account for the skipped amount due
to the presence of the bad blocks.

nand_extend_skip_bad() returns the offset where the next access
should occur.

Signed-off-by: Pantelis Antoniou <panto@antoniou-consulting.com>
---
drivers/mtd/nand/nand_util.c | 50 ++++++++++++++++++++++++++++++++++++++++++++
include/nand.h | 2 ++
2 files changed, 52 insertions(+)

diff --git a/drivers/mtd/nand/nand_util.c b/drivers/mtd/nand/nand_util.c
index 2ba0c5e..a25a4cb 100644
--- a/drivers/mtd/nand/nand_util.c
+++ b/drivers/mtd/nand/nand_util.c
@@ -684,6 +684,56 @@ int nand_read_skip_bad(nand_info_t *nand, loff_t offset, size_t *length,
return 0;
}

+/**
+ * nand_extent_skip_bad:
+ *
+ * Find the extent of a chunk, return the offset where it ends
+ * Blocks that are marked bad are skipped and the next block is examined
+ * instead as long as the extend is short enough to fit even after skipping the
+ * bad blocks.
+ *
+ * @param nand NAND device
+ * @param offset offset in flash
+ * @param length extend length
+ * @return next offset in case of success (loff_t)-1 on error
+ */
+loff_t nand_extent_skip_bad(nand_info_t *nand, loff_t offset, size_t length)
+{
+ size_t block_len, block_off;
+ loff_t block_start;
+
+ if ((offset & (nand->writesize - 1)) != 0) {
+ printf ("%s: Attempt to check extend non page aligned data\n",
+ __func__);
+ return (loff_t)-1;
+ }
+
+ while (length > 0) {
+
+ if (offset >= nand->size) {
+ printf("%s: offset >= nand->size (%llx >= %llx)\n",
+ __func__, offset, nand->size);
+ return (loff_t)-1;
+ }
+
+ block_start = offset & ~(loff_t)(nand->erasesize - 1);
+ block_off = offset & (nand->erasesize - 1);
+ block_len = nand->erasesize - block_off;
+ if (block_len > length) /* left over */
+ block_len = length;
+
+ if (!nand_block_isbad(nand, block_start))
+ length -= block_len;
+ else
+ debug("%s: bad block at %llx (left %x)\n",
+ __func__, block_start, length);
+
+ offset += block_len;
+ }
+
+ return offset;
+}
+
#ifdef CONFIG_CMD_NAND_TORTURE

/**
diff --git a/include/nand.h b/include/nand.h
index dded4e2..710c11a 100644
--- a/include/nand.h
+++ b/include/nand.h
@@ -168,3 +168,5 @@ __attribute__((noreturn)) void nand_boot(void);
#define ENV_OFFSET_SIZE 8
int get_nand_env_oob(nand_info_t *nand, unsigned long *result);
#endif
+
+loff_t nand_extent_skip_bad(nand_info_t *nand, loff_t offset, size_t length);
--
1.7.12