kernel: mtk_bmt: refactor to avoid deep recursion

[openwrt/staging/dedeckeh.git] / target / linux / generic / files / drivers / mtd / nand / mtk_bmt_v2.c

diff --git a/target/linux/generic/files/drivers/mtd/nand/mtk_bmt_v2.c b/target/linux/generic/files/drivers/mtd/nand/mtk_bmt_v2.c
index 2770376e98bb14b6d468bad14954e08cd4e5d20f..6b06948c0f45fa16bc1a3a751d2d35bcee21f914 100644 (file)
--- a/target/linux/generic/files/drivers/mtd/nand/mtk_bmt_v2.c
+++ b/target/linux/generic/files/drivers/mtd/nand/mtk_bmt_v2.c
@@ -191,36 +191,6 @@ static u16 get_bmt_index(struct bbmt *bmt)
        return 0;
 }
 
-static int
-read_bmt(u16 block, unsigned char *dat, unsigned char *fdm, int fdm_len)
-{
-       u32 len = bmtd.bmt_pgs << bmtd.pg_shift;
-
-       return bbt_nand_read(blk_pg(block), dat, len, fdm, fdm_len);
-}
-
-static struct bbbt *scan_bmt(u16 block)
-{
-       u8 fdm[4];
-
-       if (block < bmtd.pool_lba)
-               return NULL;
-
-       if (read_bmt(block, bmtd.bbt_buf, fdm, sizeof(fdm)))
-               return scan_bmt(block - 1);
-
-       if (is_valid_bmt(bmtd.bbt_buf, fdm)) {
-               bmtd.bmt_blk_idx = get_bmt_index(bmt_tbl((struct bbbt *)bmtd.bbt_buf));
-               if (bmtd.bmt_blk_idx == 0) {
-                       pr_info("[BBT] FATAL ERR: bmt block index is wrong!\n");
-                       return NULL;
-               }
-               pr_info("[BBT] BMT.v2 is found at 0x%x\n", block);
-               return (struct bbbt *)bmtd.bbt_buf;
-       } else
-               return scan_bmt(block - 1);
-}
-
 /* Write the Burner Bad Block Table to Nand Flash
  * n - write BMT to bmt_tbl[n]
  */
@@ -472,7 +442,30 @@ static int mtk_bmt_init_v2(struct device_node *np)
        /* Scanning start from the first page of the last block
         * of whole flash
         */
-       bmtd.bbt = scan_bmt(bmtd.total_blks - 1);
+       bmtd.bbt = NULL;
+       for (u16 block = bmtd.total_blks - 1; !bmtd.bbt && block >= bmtd.pool_lba; block--) {
+               u8 fdm[4];
+
+               if (bbt_nand_read(blk_pg(block), bmtd.bbt_buf, bufsz, fdm, sizeof(fdm))) {
+                       /* Read failed, try the previous block */
+                       continue;
+               }
+
+               if (!is_valid_bmt(bmtd.bbt_buf, fdm)) {
+                       /* No valid BMT found, try the previous block */
+                       continue;
+               }
+
+               bmtd.bmt_blk_idx = get_bmt_index(bmt_tbl((struct bbbt *)bmtd.bbt_buf));
+               if (bmtd.bmt_blk_idx == 0) {
+                       pr_info("[BBT] FATAL ERR: bmt block index is wrong!\n");
+                       break;
+               }
+
+               pr_info("[BBT] BMT.v2 is found at 0x%x\n", block);
+               bmtd.bbt = (struct bbbt *)bmtd.bbt_buf;
+       }
+
        if (!bmtd.bbt) {
                /* BMT not found */
                if (bmtd.total_blks > BB_TABLE_MAX + BMT_TABLE_MAX) {