[PATCH 1/2] mtd: spi-nand: Add support for randomizer

[Cheng Ming Lin <linchengming884@gmail.com>]

From: Cheng Ming Lin <chengminglin@mxic.com.tw>

Add randomizer operation support for user data scrambling.

For more high-reliability concern, if subpage write not available with
hardware ECC and then to enable randomizer is recommended by default.

Signed-off-by: Cheng Ming Lin <chengminglin@mxic.com.tw>
---
 drivers/mtd/nand/spi/core.c | 18 ++++++++++++++++++
 include/linux/mtd/spinand.h |  7 +++++++
 2 files changed, 25 insertions(+)

diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
index b0898990b2a5..43ed5de282c5 100644
--- a/drivers/mtd/nand/spi/core.c
+++ b/drivers/mtd/nand/spi/core.c
@@ -854,6 +854,19 @@ static void spinand_cont_read_init(struct spinand_device *spinand)
 	}
 }
 
+static int spinand_randomizer_init(struct spinand_device *spinand)
+{
+	int ret;
+
+	if (spinand->set_randomizer) {
+		ret = spinand->set_randomizer(spinand);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
 static bool spinand_use_cont_read(struct mtd_info *mtd, loff_t from,
 				  struct mtd_oob_ops *ops)
 {
@@ -1366,6 +1379,7 @@ int spinand_match_and_init(struct spinand_device *spinand,
 		spinand->user_otp = &table[i].user_otp;
 		spinand->read_retries = table[i].read_retries;
 		spinand->set_read_retry = table[i].set_read_retry;
+		spinand->set_randomizer = table[i].set_randomizer;
 
 		op = spinand_select_op_variant(spinand,
 					       info->op_variants.read_cache);
@@ -1543,6 +1557,10 @@ static int spinand_init(struct spinand_device *spinand)
 	 */
 	spinand_cont_read_init(spinand);
 
+	ret = spinand_randomizer_init(spinand);
+	if (ret)
+		goto err_cleanup_ecc_engine;
+
 	mtd->_read_oob = spinand_mtd_read;
 	mtd->_write_oob = spinand_mtd_write;
 	mtd->_block_isbad = spinand_mtd_block_isbad;
diff --git a/include/linux/mtd/spinand.h b/include/linux/mtd/spinand.h
index 27a45bdab7ec..80a5c6ac6cc5 100644
--- a/include/linux/mtd/spinand.h
+++ b/include/linux/mtd/spinand.h
@@ -499,6 +499,7 @@ struct spinand_user_otp {
  * @user_otp: SPI NAND user OTP info.
  * @read_retries: the number of read retry modes supported
  * @set_read_retry: enable/disable read retry for data recovery
+ * @set_randomizer: enable randomizer
  *
  * Each SPI NAND manufacturer driver should have a spinand_info table
  * describing all the chips supported by the driver.
@@ -525,6 +526,7 @@ struct spinand_info {
 	unsigned int read_retries;
 	int (*set_read_retry)(struct spinand_device *spinand,
 			     unsigned int read_retry);
+	int (*set_randomizer)(struct spinand_device *spinand);
 };
 
 #define SPINAND_ID(__method, ...)					\
@@ -578,6 +580,9 @@ struct spinand_info {
 	.read_retries = __read_retries,					\
 	.set_read_retry = __set_read_retry
 
+#define SPINAND_RANDOMIZER(__set_randomizer)				\
+	.set_randomizer = __set_randomizer
+
 #define SPINAND_INFO(__model, __id, __memorg, __eccreq, __op_variants,	\
 		     __flags, ...)					\
 	{								\
@@ -633,6 +638,7 @@ struct spinand_dirmap {
  * @user_otp: SPI NAND user OTP info.
  * @read_retries: the number of read retry modes supported
  * @set_read_retry: Enable/disable the read retry feature
+ * @set_randomizer: Enable the randomizer feature
  */
 struct spinand_device {
 	struct nand_device base;
@@ -673,6 +679,7 @@ struct spinand_device {
 	unsigned int read_retries;
 	int (*set_read_retry)(struct spinand_device *spinand,
 			     unsigned int retry_mode);
+	int (*set_randomizer)(struct spinand_device *spinand);
 };
 
 /**
-- 
2.25.1