mtd: nand: add 'oob_required' argument to NAND {read,write}_page interfaces

New NAND controllers can perform read/write via HW engines which don't expose
OOB data in their DMA mode. To reflect this, we should rework the nand_chip /
nand_ecc_ctrl interfaces that assume that drivers will always read/write OOB
data in the nand_chip.oob_poi buffer. A better interface includes a boolean
argument that explicitly tells the callee when OOB data is requested by the
calling layer (for reading/writing to/from nand_chip.oob_poi).

This patch adds the 'oob_required' parameter to each relevant {read,write}_page
interface; all 'oob_required' parameters are left unused for now. The next
patch will set the parameter properly in the nand_base.c callers, and follow-up
patches will make use of 'oob_required' in some of the callee functions.

Note that currently, there is no harm in ignoring the 'oob_required' parameter
and *always* utilizing nand_chip.oob_poi, but there can be
performance/complexity/design benefits from avoiding filling oob_poi in the
common case. I will try to implement this for some drivers which can be ported
easily.

Note: I couldn't compile-test all of these easily, as some had ARCH
dependencies.

[dwmw2: Merge later 1/0 vs. true/false cleanup]
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Reviewed-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Acked-by: Jiandong Zheng <jdzheng@broadcom.com>
Acked-by: Mike Dunn <mikedunn@newsguy.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 94a6679bfc2e..c7755f455c81 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -360,15 +360,15 @@ struct nand_ecc_ctrl {
         int (*correct)(struct mtd_info *mtd, uint8_t *dat, uint8_t *read_ecc,
                         uint8_t *calc_ecc);
         int (*read_page_raw)(struct mtd_info *mtd, struct nand_chip *chip,
-                        uint8_t *buf, int page);
+                        uint8_t *buf, int oob_required, int page);
         void (*write_page_raw)(struct mtd_info *mtd, struct nand_chip *chip,
-                        const uint8_t *buf);
+                        const uint8_t *buf, int oob_required);
         int (*read_page)(struct mtd_info *mtd, struct nand_chip *chip,
-                        uint8_t *buf, int page);
+                        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);
         void (*write_page)(struct mtd_info *mtd, struct nand_chip *chip,
-                        const uint8_t *buf);
+                        const uint8_t *buf, int oob_required);
         int (*write_oob_raw)(struct mtd_info *mtd, struct nand_chip *chip,
                         int page);
         int (*read_oob_raw)(struct mtd_info *mtd, struct nand_chip *chip,
@@ -504,7 +504,8 @@ struct nand_chip {
         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 page, int cached, int raw);
+                        const uint8_t *buf, int oob_required, int page,
+                        int cached, int raw);
 
         int chip_delay;
         unsigned int options;