mtd: bcm47xxpart: detect block aligned Squashfs partition

Most of the bcm47xx devices use TRX format for storing kernel and some
partition like Squashfs or JFFS2. This is pretty flexible solution, CFE
(the bootloader) just writes (and later boots) TRX at some hardcoded
place and paritions can vary in the size.

However some devices don't use TRX format. Very recently we have
discovered ZTE H218N that has kernel and rootfs partitions at some
"random" places.

This patch allows Linux find a rootfs partition after installing custom
image with a CFE bootloader.

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

diff --git a/drivers/mtd/bcm47xxpart.c b/drivers/mtd/bcm47xxpart.c
index 6d427468c4cdba0ef51334a0043080a08608c2a9..a737450826eca55e4e283963a9c14bac9ec67450 100644 (file)
--- a/drivers/mtd/bcm47xxpart.c
+++ b/drivers/mtd/bcm47xxpart.c
@@ -32,6 +32,7 @@
 #define ML_MAGIC1                      0x39685a42
 #define ML_MAGIC2                      0x26594131
 #define TRX_MAGIC                      0x30524448
+#define SQSH_MAGIC                     0x71736873      /* shsq */
 
 struct trx_header {
        uint32_t magic;
@@ -174,6 +175,13 @@ static int bcm47xxpart_parse(struct mtd_info *master,
                        offset = rounddown(offset + trx->length, blocksize);
                        continue;
                }
+
+               /* Squashfs on devices not using TRX */
+               if (buf[0x000 / 4] == SQSH_MAGIC) {
+                       bcm47xxpart_add_part(&parts[curr_part++], "rootfs",
+                                            offset, 0);
+                       continue;
+               }
        }
 
        /* Look for NVRAM at the end of the last block. */