On Mon, 2013-09-30 at 23:52 +0530, Pekon Gupta wrote:
From: Matthieu CASTET matthieu.castet@parrot.com
This patch is modified version from following linux patch http://lists.infradead.org/pipermail/linux-mtd/2012-November/044803.html So retaining the authorship to Matthieu CASTET matthieu.castet@parrot.com
*Modifications from original patch* (1) use CONFIG_SYS_NAND_ONFI_DETECTION instead of (chip->options & NAND_BUSWIDTH_AUTO) (2) allow re-assigning of callbacks in nand_set_defaults() depending on bus-width
*Original patch message* The driver call nand_scan_ident in 8 bit mode, then readid or onfi detection are done (and detect bus width). The driver should update its bus width before calling nand_scan_tail.
This work because readid and onfi are read work 8 byte mode.
Note that nand_scan_ident send command (NAND_CMD_RESET, NAND_CMD_READID, NAND_CMD_PARAM), address and read data The ONFI specificication is not very clear for x16 device if high byte of address should be driven to 0, but according to [1] it should be ok to not drive it during autodetection.
[1] 3.3.2. Target Initialization
[...] The Read ID and Read Parameter Page commands only use the lower 8-bits of the data bus. The host shall not issue commands that use a word data width on x16 devices until the host determines the device supports a 16-bit data bus width in the parameter page.
Signed-off-by: Pekon Gupta pekon@ti.com
drivers/mtd/nand/nand_base.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index 9e05cef..4ef0edb 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -2514,7 +2514,7 @@ static void nand_set_defaults(struct nand_chip *chip, int busw)
if (!chip->select_chip) chip->select_chip = nand_select_chip;
- if (!chip->read_byte)
- if ((!chip->read_byte) || (chip->read_byte == nand_read_byte)) chip->read_byte = busw ? nand_read_byte16 : nand_read_byte;
Unnecessary parens (and doesn't match equivalent Linux code).
This change corresponds to Linux commit 68e8078072e802e77134664f11d2ffbfbd2f8fbe.
-Scott