mtd: bcm47xxpart: alternative MAGIC for board_data partition

Some devices (like WNDR3700v3) have board_data without MPFR magic, some
extra header or extra NVRAM around 0x100. In such case we have to look
for another magic which is BD 0B 0D BD (BD probably stands for Board
Data). It's located "far far away", so instead of extending buffer add
another mtd_read.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/mtd/bcm47xxpart.c b/drivers/mtd/bcm47xxpart.c
index 877c17c7f5d3..de1eb92e42f5 100644
--- a/drivers/mtd/bcm47xxpart.c
+++ b/drivers/mtd/bcm47xxpart.c
@@ -27,6 +27,7 @@
 
 /* Magics */
 #define BOARD_DATA_MAGIC                0x5246504D      /* MPFR */
+#define BOARD_DATA_MAGIC2               0xBD0D0BBD
 #define CFE_MAGIC                       0x43464531      /* 1EFC */
 #define FACTORY_MAGIC                   0x59544346      /* FCTY */
 #define POT_MAGIC1                      0x54544f50      /* POTT */
@@ -192,6 +193,21 @@ static int bcm47xxpart_parse(struct mtd_info *master,
                                              offset, 0);
                         continue;
                 }
+
+                /* Read middle of the block */
+                if (mtd_read(master, offset + 0x8000, 0x4,
+                             &bytes_read, (uint8_t *)buf) < 0) {
+                        pr_err("mtd_read error while parsing (offset: 0x%X)!\n",
+                               offset);
+                        continue;
+                }
+
+                /* Some devices (ex. WNDR3700v3) don't have a standard 'MPFR' */
+                if (buf[0x000 / 4] == BOARD_DATA_MAGIC2) {
+                        bcm47xxpart_add_part(&parts[curr_part++], "board_data",
+                                             offset, MTD_WRITEABLE);
+                        continue;
+                }
         }
 
         /* Look for NVRAM at the end of the last block. */