mtd: bcm47xxpart: look for NVRAM at the end of device

NVRAM is always placed at the end of device and it does not have to
start at the beginning of a block, so check few possible offsets.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

diff --git a/drivers/mtd/bcm47xxpart.c b/drivers/mtd/bcm47xxpart.c
index 4552afb..9279a91 100644 (file)
--- a/drivers/mtd/bcm47xxpart.c
+++ b/drivers/mtd/bcm47xxpart.c
@@ -63,6 +63,7 @@ static int bcm47xxpart_parse(struct mtd_info *master,
        struct trx_header *trx;
        int trx_part = -1;
        int last_trx_part = -1;
+       int possible_nvram_sizes[] = { 0x8000, 0xF000, 0x10000, };
 
        if (blocksize <= 0x10000)
                blocksize = 0x10000;
@@ -99,13 +100,6 @@ static int bcm47xxpart_parse(struct mtd_info *master,
                        continue;
                }
 
-               /* Standard NVRAM */
-               if (buf[0x000 / 4] == NVRAM_HEADER) {
-                       bcm47xxpart_add_part(&parts[curr_part++], "nvram",
-                                            offset, 0);
-                       continue;
-               }
-
                /*
                 * board_data starts with board_id which differs across boards,
                 * but we can use 'MPFR' (hopefully) magic at 0x100
@@ -174,6 +168,30 @@ static int bcm47xxpart_parse(struct mtd_info *master,
                        continue;
                }
        }
+
+       /* Look for NVRAM at the end of the last block. */
+       for (i = 0; i < ARRAY_SIZE(possible_nvram_sizes); i++) {
+               if (curr_part > BCM47XXPART_MAX_PARTS) {
+                       pr_warn("Reached maximum number of partitions, scanning stopped!\n");
+                       break;
+               }
+
+               offset = master->size - possible_nvram_sizes[i];
+               if (mtd_read(master, offset, 0x4, &bytes_read,
+                            (uint8_t *)buf) < 0) {
+                       pr_err("mtd_read error while reading at offset 0x%X!\n",
+                              offset);
+                       continue;
+               }
+
+               /* Standard NVRAM */
+               if (buf[0] == NVRAM_HEADER) {
+                       bcm47xxpart_add_part(&parts[curr_part++], "nvram",
+                                            master->size - blocksize, 0);
+                       break;
+               }
+       }
+
        kfree(buf);
 
        /*