From: Karl Beldan karl.beldan@gmail.com

Some chips require a RESET after power-up (e.g. Micron MT29FxGxxxxx). The first command sent is NAND_CMD_READID. Issue a NAND_CMD_RESET in nand_scan_ident before reading the device id. Tested with an MT29F4G08AAC.

Signed-off-by: Karl Beldan karl.beldan@gmail.com Signed-off-by: Scott Wood scottwood@freescale.com --- Applied to u-boot-nand-flash

drivers/mtd/nand/nand_base.c | 8 ++++++++ 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index 4069ab1..ba05b76 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -2450,6 +2450,12 @@ static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd, /* Select the device */ chip->select_chip(mtd, 0);

+ /* + * Reset the chip, required by some chips (e.g. Micron MT29FxGxxxxx) + * after power-up + */ + chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1); + /* Send the command for reading device ID */ chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);

@@ -2620,6 +2626,8 @@ int nand_scan_ident(struct mtd_info *mtd, int maxchips) /* Check for a chip array */ for (i = 1; i < maxchips; i++) { chip->select_chip(mtd, i); + /* See comment in nand_get_flash_type for reset */ + chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1); /* Send the command for reading device ID */ chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1); /* Read manufacturer and device IDs */