Revert "mtd: bcm47xxpart: improve probing of nvram partition"

This reverts commit be3781b71ac03723b552dc156931620634ef1b22.

Some CFE bootloaders have NVRAM at offset 0x1000. With that patch we
were detecting such a bootloaders as a standard NVRAM partition.
Changing anything in this pseudo-NVRAM resulted in corrupted bootloader
and bricked device!

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 63feb75cc8e01d2048949343955023b01fc7fadc..4552afbad4d006f6bd0ed6a18f0e9a5f60621abd 100644 (file)
--- a/drivers/mtd/bcm47xxpart.c
+++ b/drivers/mtd/bcm47xxpart.c
@@ -19,6 +19,12 @@
 /* 10 parts were found on sflash on Netgear WNDR4500 */
 #define BCM47XXPART_MAX_PARTS          12
 
+/*
+ * Amount of bytes we read when analyzing each block of flash memory.
+ * Set it big enough to allow detecting partition and reading important data.
+ */
+#define BCM47XXPART_BYTES_TO_READ      0x404
+
 /* Magics */
 #define BOARD_DATA_MAGIC               0x5246504D      /* MPFR */
 #define POT_MAGIC1                     0x54544f50      /* POTT */
@@ -57,17 +63,14 @@ static int bcm47xxpart_parse(struct mtd_info *master,
        struct trx_header *trx;
        int trx_part = -1;
        int last_trx_part = -1;
-       int max_bytes_to_read = 0x8004;
 
        if (blocksize <= 0x10000)
                blocksize = 0x10000;
-       if (blocksize == 0x20000)
-               max_bytes_to_read = 0x18004;
 
        /* Alloc */
        parts = kzalloc(sizeof(struct mtd_partition) * BCM47XXPART_MAX_PARTS,
                        GFP_KERNEL);
-       buf = kzalloc(max_bytes_to_read, GFP_KERNEL);
+       buf = kzalloc(BCM47XXPART_BYTES_TO_READ, GFP_KERNEL);
 
        /* Parse block by block looking for magics */
        for (offset = 0; offset <= master->size - blocksize;
@@ -82,7 +85,7 @@ static int bcm47xxpart_parse(struct mtd_info *master,
                }
 
                /* Read beginning of the block */
-               if (mtd_read(master, offset, max_bytes_to_read,
+               if (mtd_read(master, offset, BCM47XXPART_BYTES_TO_READ,
                             &bytes_read, (uint8_t *)buf) < 0) {
                        pr_err("mtd_read error while parsing (offset: 0x%X)!\n",
                               offset);
@@ -97,16 +100,9 @@ static int bcm47xxpart_parse(struct mtd_info *master,
                }
 
                /* Standard NVRAM */
-               if (buf[0x000 / 4] == NVRAM_HEADER ||
-                   buf[0x1000 / 4] == NVRAM_HEADER ||
-                   buf[0x8000 / 4] == NVRAM_HEADER ||
-                   (blocksize == 0x20000 && (
-                     buf[0x10000 / 4] == NVRAM_HEADER ||
-                     buf[0x11000 / 4] == NVRAM_HEADER ||
-                     buf[0x18000 / 4] == NVRAM_HEADER))) {
+               if (buf[0x000 / 4] == NVRAM_HEADER) {
                        bcm47xxpart_add_part(&parts[curr_part++], "nvram",
                                             offset, 0);
-                       offset = rounddown(offset, blocksize);
                        continue;
                }