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authorUwe Kleine-König <u.kleine-koenig@pengutronix.de>2013-12-05 22:22:04 +0100
committerBrian Norris <computersforpeace@gmail.com>2014-01-14 17:22:37 -0800
commit05f7835975dad6b3b517f9e23415985e648fb875 (patch)
treeed86b42f8dc1c6a5704728c075abb92f6a1e4bf0 /include/linux/mtd
parente2e6b7b7d64baeac1c38fa5eb0d3ec85f3d123f5 (diff)
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op-kernel-dev-05f7835975dad6b3b517f9e23415985e648fb875.tar.gz
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')
-rw-r--r--include/linux/mtd/nand.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 05fcdfe..352e238 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);
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