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>

15 files changed, 90 insertions, 72 deletions

diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
index 9a7876e8de42..97ac6712bb19 100644
--- a/drivers/mtd/nand/atmel_nand.c
+++ b/drivers/mtd/nand/atmel_nand.c
@@ -324,9 +324,10 @@ static int atmel_nand_calculate(struct mtd_info *mtd,
  * mtd:        mtd info structure
  * chip:       nand chip info structure
  * buf:        buffer to store read data
+ * oob_required:    caller expects OOB data read to chip->oob_poi
  */
-static int atmel_nand_read_page(struct mtd_info *mtd,
-                struct nand_chip *chip, uint8_t *buf, int page)
+static int atmel_nand_read_page(struct mtd_info *mtd, struct nand_chip *chip,
+                                uint8_t *buf, int oob_required, int page)
 {
         int eccsize = chip->ecc.size;
         int eccbytes = chip->ecc.bytes;
diff --git a/drivers/mtd/nand/bcm_umi_bch.c b/drivers/mtd/nand/bcm_umi_bch.c
index f8472b49567a..5914bb32e001 100644
--- a/drivers/mtd/nand/bcm_umi_bch.c
+++ b/drivers/mtd/nand/bcm_umi_bch.c
@@ -22,9 +22,9 @@
 
 /* ---- Private Function Prototypes -------------------------------------- */
 static int bcm_umi_bch_read_page_hwecc(struct mtd_info *mtd,
-        struct nand_chip *chip, uint8_t *buf, int page);
+        struct nand_chip *chip, uint8_t *buf, int oob_required, int page);
 static void bcm_umi_bch_write_page_hwecc(struct mtd_info *mtd,
-        struct nand_chip *chip, const uint8_t *buf);
+        struct nand_chip *chip, const uint8_t *buf, int oob_required);
 
 /* ---- Private Variables ------------------------------------------------ */
 
@@ -103,11 +103,12 @@ static struct nand_ecclayout nand_hw_eccoob_4096 = {
 *  @mtd:        mtd info structure
 *  @chip:       nand chip info structure
 *  @buf:        buffer to store read data
+*  @oob_required:       caller expects OOB data read to chip->oob_poi
 *
 ***************************************************************************/
 static int bcm_umi_bch_read_page_hwecc(struct mtd_info *mtd,
                                        struct nand_chip *chip, uint8_t * buf,
-                                                 int page)
+                                       int oob_required, int page)
 {
         int sectorIdx = 0;
         int eccsize = chip->ecc.size;
@@ -190,10 +191,11 @@ static int bcm_umi_bch_read_page_hwecc(struct mtd_info *mtd,
 *  @mtd:        mtd info structure
 *  @chip:       nand chip info structure
 *  @buf:        data buffer
+*  @oob_required:       must write chip->oob_poi to OOB
 *
 ***************************************************************************/
 static void bcm_umi_bch_write_page_hwecc(struct mtd_info *mtd,
-        struct nand_chip *chip, const uint8_t *buf)
+        struct nand_chip *chip, const uint8_t *buf, int oob_required)
 {
         int sectorIdx = 0;
         int eccsize = chip->ecc.size;
diff --git a/drivers/mtd/nand/bcm_umi_nand.c b/drivers/mtd/nand/bcm_umi_nand.c
index 7134adfa1089..c855e7cd337b 100644
--- a/drivers/mtd/nand/bcm_umi_nand.c
+++ b/drivers/mtd/nand/bcm_umi_nand.c
@@ -341,7 +341,7 @@ static int bcm_umi_nand_verify_buf(struct mtd_info *mtd, const u_char * buf,
          * for MLC parts which may have permanently stuck bits.
          */
         struct nand_chip *chip = mtd->priv;
-        int ret = chip->ecc.read_page(mtd, chip, readbackbuf, 0);
+        int ret = chip->ecc.read_page(mtd, chip, readbackbuf, 0, 0);
         if (ret < 0)
                 return -EFAULT;
         else {
diff --git a/drivers/mtd/nand/bf5xx_nand.c b/drivers/mtd/nand/bf5xx_nand.c
index d7b86b925de5..3f1c18599cbd 100644
--- a/drivers/mtd/nand/bf5xx_nand.c
+++ b/drivers/mtd/nand/bf5xx_nand.c
@@ -558,7 +558,7 @@ static void bf5xx_nand_dma_write_buf(struct mtd_info *mtd,
 }
 
 static int bf5xx_nand_read_page_raw(struct mtd_info *mtd, struct nand_chip *chip,
-                uint8_t *buf, int page)
+                uint8_t *buf, int oob_required, int page)
 {
         bf5xx_nand_read_buf(mtd, buf, mtd->writesize);
         bf5xx_nand_read_buf(mtd, chip->oob_poi, mtd->oobsize);
@@ -567,7 +567,7 @@ static int bf5xx_nand_read_page_raw(struct mtd_info *mtd, struct nand_chip *chip
 }
 
 static void bf5xx_nand_write_page_raw(struct mtd_info *mtd, struct nand_chip *chip,
-                const uint8_t *buf)
+                const uint8_t *buf, int oob_required)
 {
         bf5xx_nand_write_buf(mtd, buf, mtd->writesize);
         bf5xx_nand_write_buf(mtd, chip->oob_poi, mtd->oobsize);
diff --git a/drivers/mtd/nand/cafe_nand.c b/drivers/mtd/nand/cafe_nand.c
index 75fb77b96efb..3a6c88d69bc7 100644
--- a/drivers/mtd/nand/cafe_nand.c
+++ b/drivers/mtd/nand/cafe_nand.c
@@ -375,12 +375,13 @@ static int cafe_nand_read_oob(struct mtd_info *mtd, struct nand_chip *chip,
  * @mtd:        mtd info structure
  * @chip:       nand chip info structure
  * @buf:        buffer to store read data
+ * @oob_required:       caller expects OOB data read to chip->oob_poi
  *
  * The hw generator calculates the error syndrome automatically. Therefor
  * we need a special oob layout and handling.
  */
 static int cafe_nand_read_page(struct mtd_info *mtd, struct nand_chip *chip,
-                               uint8_t *buf, int page)
+                               uint8_t *buf, int oob_required, int page)
 {
         struct cafe_priv *cafe = mtd->priv;
         unsigned int max_bitflips = 0;
@@ -520,7 +521,8 @@ static struct nand_bbt_descr cafe_bbt_mirror_descr_512 = {
 
 
 static void cafe_nand_write_page_lowlevel(struct mtd_info *mtd,
-                                          struct nand_chip *chip, const uint8_t *buf)
+                                          struct nand_chip *chip,
+                                          const uint8_t *buf, int oob_required)
 {
         struct cafe_priv *cafe = mtd->priv;
 
@@ -532,16 +534,17 @@ static void cafe_nand_write_page_lowlevel(struct mtd_info *mtd,
 }
 
 static int cafe_nand_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 status;
 
         chip->cmdfunc(mtd, NAND_CMD_SEQIN, 0x00, page);
 
         if (unlikely(raw))