[PATCH 1/2] mtd: spinand: Add function to read parameter page

[PATCH 1/2] mtd: spinand: Add function to read parameter page

[Shivamurthy Shastri (sshivamurthy)]

Some of the manufacturers support parameter page, which can be used
to get the device details during detection.

This function reads parameter page and this page can be accessed by
set of commands, which are common across the manufacturers.

Signed-off-by: Shivamurthy Shastri <sshivamurthy@micron.com>
Reviewed-by: Bean Huo <beanhuo@micron.com>
---
 drivers/mtd/nand/spi/core.c | 62 +++++++++++++++++++++++++++++++++++++
 include/linux/mtd/spinand.h |  3 ++
 2 files changed, 65 insertions(+)

diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
index 479c2f2cf17f..12f3ace373cb 100644
--- a/drivers/mtd/nand/spi/core.c
+++ b/drivers/mtd/nand/spi/core.c
@@ -463,6 +463,68 @@ static int spinand_lock_block(struct spinand_device *spinand, u8 lock)
 	return spinand_write_reg_op(spinand, REG_BLOCK_LOCK, lock);
 }
 
+/**
+ * spinand_read_param_page_op - Read parameter page operation
+ * @spinand: the spinand device
+ * @page: page number where parameter page tables can be found
+ * @parameters: buffer used to store the parameter page
+ * @len: length of the buffer
+ *
+ * Read parameter page
+ *
+ * Returns 0 on success, a negative error code otherwise.
+ */
+int spinand_parameter_page_read(struct spinand_device *spinand,
+				u8 page, void *parameters, u32 len)
+{
+	struct spi_mem_op pread_op = SPINAND_PAGE_READ_OP(page);
+	struct spi_mem_op pread_cache_op =
+				SPINAND_PAGE_READ_FROM_CACHE_OP(false,
+								0,
+								1,
+								parameters,
+								len);
+	u8 feature;
+	u8 status;
+	int ret;
+
+	if (len && !parameters)
+		return -EINVAL;
+
+	ret = spinand_read_reg_op(spinand, REG_CFG,
+				  &feature);
+	if (ret)
+		return ret;
+
+	/* CFG_OTP_ENABLE is used to enable parameter page access */
+	feature |= CFG_OTP_ENABLE;
+
+	spinand_write_reg_op(spinand, REG_CFG, feature);
+
+	ret = spi_mem_exec_op(spinand->spimem, &pread_op);
+	if (ret)
+		return ret;
+
+	ret = spinand_wait(spinand, &status);
+	if (ret < 0)
+		return ret;
+
+	ret = spi_mem_exec_op(spinand->spimem, &pread_cache_op);
+	if (ret)
+		return ret;
+
+	ret = spinand_read_reg_op(spinand, REG_CFG,
+				  &feature);
+	if (ret)
+		return ret;
+
+	feature &= ~CFG_OTP_ENABLE;
+
+	spinand_write_reg_op(spinand, REG_CFG, feature);
+
+	return 0;
+}
+
 static int spinand_check_ecc_status(struct spinand_device *spinand, u8 status)
 {
 	struct nand_device *nand = spinand_to_nand(spinand);
diff --git a/include/linux/mtd/spinand.h b/include/linux/mtd/spinand.h
index b92e2aa955b6..9062bdbaefdd 100644
--- a/include/linux/mtd/spinand.h
+++ b/include/linux/mtd/spinand.h
@@ -420,4 +420,7 @@ int spinand_match_and_init(struct spinand_device *dev,
 int spinand_upd_cfg(struct spinand_device *spinand, u8 mask, u8 val);
 int spinand_select_target(struct spinand_device *spinand, unsigned int target);
 
+int spinand_parameter_page_read(struct spinand_device *spinand,
+				u8 page, void *parameters, u32 len);
+
 #endif /* __LINUX_MTD_SPINAND_H */
-- 
2.17.1

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