mtd: nand: subpage write support for hardware based ECC schemes
This patch adds support for subpage (partial-page) writes when using
hardware based ECC schemes.
Advantages:
(1) reduces storage overhead when using file-systems like UBIFS, which
store LEB header at page-size granularity.
(2) allows independent subpage writes, thereby increasing NAND storage
efficiency for non-page aligned data.
+ updated cafe_nand and lpc32xx_mlc NAND drivers for change in
chip->write_page interface.
Signed-off-by: Gupta, Pekon <pekon@ti.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index ebf970e..ab63634 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -318,6 +318,7 @@
* any single ECC step, 0 if bitflips uncorrectable, -EIO hw error
* @read_subpage: function to read parts of the page covered by ECC;
* returns same as read_page()
+ * @write_subpage: function to write parts of the page covered by ECC.
* @write_page: function to write a page according to the ECC generator
* requirements.
* @write_oob_raw: function to write chip OOB data without ECC
@@ -349,6 +350,9 @@
uint8_t *buf, int oob_required, int page);
int (*read_subpage)(struct mtd_info *mtd, struct nand_chip *chip,
uint32_t offs, uint32_t len, uint8_t *buf);
+ int (*write_subpage)(struct mtd_info *mtd, struct nand_chip *chip,
+ uint32_t offset, uint32_t data_len,
+ const uint8_t *data_buf, int oob_required);
int (*write_page)(struct mtd_info *mtd, struct nand_chip *chip,
const uint8_t *buf, int oob_required);
int (*write_oob_raw)(struct mtd_info *mtd, struct nand_chip *chip,
@@ -484,8 +488,8 @@
int (*errstat)(struct mtd_info *mtd, struct nand_chip *this, int state,
int status, int page);
int (*write_page)(struct mtd_info *mtd, struct nand_chip *chip,
- const uint8_t *buf, int oob_required, int page,
- int cached, int raw);
+ uint32_t offset, int data_len, const uint8_t *buf,
+ int oob_required, int page, int cached, int raw);
int (*onfi_set_features)(struct mtd_info *mtd, struct nand_chip *chip,
int feature_addr, uint8_t *subfeature_para);
int (*onfi_get_features)(struct mtd_info *mtd, struct nand_chip *chip,