Merge tag 'for-linus-20130318' of git://git.infradead.org/linux-mtd

Pull MTD fixes from David Woodhouse:
 "This fixes a couple of problems.  Firstly, some people are actually
  still using old small-page flash and we broke it by removing the ready
  check.

  Secondly.  fix the handling of partitions on Broadcom 47xx devices.
  Recent changes had made it misdetect the location of the NVRAM and
  scribble over the bootloader when it tried to update the variables
  there.  With predictably sad results."

* tag 'for-linus-20130318' of git://git.infradead.org/linux-mtd:
  mtd: nand: reintroduce NAND_NO_READRDY as NAND_NEED_READRDY
  mtd: bcm47xxpart: look for NVRAM at the end of device
  Revert "mtd: bcm47xxpart: improve probing of nvram partition"

1 files changed, 33 insertions, 19 deletions

diff --git a/drivers/mtd/bcm47xxpart.c b/drivers/mtd/bcm47xxpart.c
index 63feb75..9279a91 100644
--- 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 +63,15 @@ 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;
+	int possible_nvram_sizes[] = { 0x8000, 0xF000, 0x10000, };
 
 	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 +86,7 @@ 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);
@@ -96,20 +100,6 @@ static int bcm47xxpart_parse(struct mtd_info *master,
 			continue;
 		}
 
-		/* 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))) {
-			bcm47xxpart_add_part(&parts[curr_part++], "nvram",
-					     offset, 0);
-			offset = rounddown(offset, blocksize);
-			continue;
-		}
-
 		/*
 		 * board_data starts with board_id which differs across boards,
 		 * but we can use 'MPFR' (hopefully) magic at 0x100
@@ -178,6 +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);
 
 	/*