kernel: mtk_bmt: add support for limiting range of remapping

This can be used to support ubi on top of mtk_bmt without reflashing the
boot loader. The boot loader + factory + kernel area is covered, while the
rest is passed through as-is

Signed-off-by: Felix Fietkau <nbd@nbd.name>

diff --git a/target/linux/generic/files/drivers/mtd/nand/mtk_bmt.c b/target/linux/generic/files/drivers/mtd/nand/mtk_bmt.c
index cb74b4d10f134241e7049ce9c23d56bd48b46bcf..14fbd246d7262fcf6008d9a66f570706408fb6b3 100644 (file)
--- a/target/linux/generic/files/drivers/mtd/nand/mtk_bmt.c
+++ b/target/linux/generic/files/drivers/mtd/nand/mtk_bmt.c
@@ -90,6 +90,9 @@ static struct bmt_desc {
        /* How many pages needs to store 'struct bbbt' */
        u32 bmt_pgs;
 
+       const __be32 *remap_range;
+       int remap_range_len;
+
        /* to compensate for driver level remapping */
        u8 oob_offset;
 } bmtd = {0};
@@ -458,17 +461,32 @@ static bool update_bmt(u16 block, int copy_len)
        return true;
 }
 
+static bool
+mapping_block_in_range(int block)
+{
+       const __be32 *cur = bmtd.remap_range;
+       u32 addr = block << bmtd.blk_shift;
+       int i;
+
+       if (!cur || !bmtd.remap_range_len)
+               return true;
+
+       for (i = 0; i < bmtd.remap_range_len; i++, cur += 2)
+               if (addr >= be32_to_cpu(cur[0]) && addr < be32_to_cpu(cur[1]))
+                       return true;
+
+       return false;
+}
+
 u16 get_mapping_block_index(int block)
 {
-       int mapping_block;
+       if (block >= bmtd.pool_lba)
+               return block;
 
-       if (block < bmtd.pool_lba)
-               mapping_block = bmtd.bbt->bb_tbl[block];
-       else
-               mapping_block = block;
-       BBT_LOG("0x%x mapped to 0x%x", block, mapping_block);
+       if (!mapping_block_in_range(block))
+               return block;
 
-       return mapping_block;
+       return bmtd.bbt->bb_tbl[block];
 }
 
 static int
@@ -839,6 +857,10 @@ int mtk_bmt_attach(struct mtd_info *mtd)
                                 &bmt_table_size) != 0)
                bmt_table_size = 0x2000U;
 
+       bmtd.remap_range = of_get_property(np, "mediatek,bmt-remap-range",
+                                          &bmtd.remap_range_len);
+       bmtd.remap_range_len /= 8;
+
        bmtd.mtd = mtd;
        mtk_bmt_replace_ops(mtd);