diff options
| author | Uwe Kleine-König <u.kleine-koenig@pengutronix.de> | 2013-12-05 22:22:04 +0100 |
|---|---|---|
| committer | Brian Norris <computersforpeace@gmail.com> | 2014-01-14 17:22:37 -0800 |
| commit | 05f7835975dad6b3b517f9e23415985e648fb875 (patch) | |
| tree | ed86b42f8dc1c6a5704728c075abb92f6a1e4bf0 /include/linux/mtd/nand.h | |
| parent | e2e6b7b7d64baeac1c38fa5eb0d3ec85f3d123f5 (diff) | |
mtd: nand: don't use {read,write}_buf for 8-bit transfers
According to the Open NAND Flash Interface Specification (ONFI) Revision
3.1 "Parameters are always transferred on the lower 8-bits of the data
bus." for the Get Features and Set Features commands.
So using read_buf and write_buf is wrong for 16-bit wide nand chips as
they use I/O[15:0]. The Get Features command is easily fixed using 4
times the read_byte callback. For Set Features implement a new
overwritable callback "write_byte". Still I expect the default to work
just fine for all controllers and making it overwriteable was just done
for symmetry.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
[Brian: fixed warning]
Tested-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Diffstat (limited to 'include/linux/mtd/nand.h')
| -rw-r--r-- | include/linux/mtd/nand.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h index 05fcdfea640..352e23891f5 100644 --- a/include/linux/mtd/nand.h +++ b/include/linux/mtd/nand.h @@ -456,6 +456,8 @@ struct nand_buffers { * flash device. * @read_byte: [REPLACEABLE] read one byte from the chip * @read_word: [REPLACEABLE] read one word from the chip + * @write_byte: [REPLACEABLE] write a single byte to the chip on the + * low 8 I/O lines * @write_buf: [REPLACEABLE] write data from the buffer to the chip * @read_buf: [REPLACEABLE] read data from the chip into the buffer * @select_chip: [REPLACEABLE] select chip nr @@ -548,6 +550,7 @@ struct nand_chip { uint8_t (*read_byte)(struct mtd_info *mtd); u16 (*read_word)(struct mtd_info *mtd); + void (*write_byte)(struct mtd_info *mtd, uint8_t byte); void (*write_buf)(struct mtd_info *mtd, const uint8_t *buf, int len); void (*read_buf)(struct mtd_info *mtd, uint8_t *buf, int len); void (*select_chip)(struct mtd_info *mtd, int chip); |