mtd: spinand: otp: add helpers functions

The global functions spinand_otp_read() and spinand_otp_write() have
been introduced. Since most SPI-NAND flashes read/write OTP in the same
way, let's define global functions to avoid code duplication.

Signed-off-by: Martin Kurbanov <mmkurbanov@salutedevices.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

2 files changed, 116 insertions, 0 deletions

diff --git a/drivers/mtd/nand/spi/otp.c b/drivers/mtd/nand/spi/otp.c
index af9a7a69fc0f..ce41bca86ea9 100644
--- a/drivers/mtd/nand/spi/otp.c
+++ b/drivers/mtd/nand/spi/otp.c
@@ -66,6 +66,115 @@ static int spinand_user_otp_check_bounds(struct spinand_device *spinand,
 					&spinand->user_otp->layout);
 }
 
+static int spinand_otp_rw(struct spinand_device *spinand, loff_t ofs,
+			  size_t len, size_t *retlen, u8 *buf, bool is_write,
+			  const struct spinand_otp_layout *layout)
+{
+	struct nand_page_io_req req = {};
+	unsigned long long page;
+	size_t copied = 0;
+	size_t otp_pagesize = spinand_otp_page_size(spinand);
+	int ret;
+
+	if (!len)
+		return 0;
+
+	ret = spinand_otp_check_bounds(spinand, ofs, len, layout);
+	if (ret)
+		return ret;
+
+	ret = spinand_upd_cfg(spinand, CFG_OTP_ENABLE, CFG_OTP_ENABLE);
+	if (ret)
+		return ret;
+
+	page = ofs;
+	req.dataoffs = do_div(page, otp_pagesize);
+	req.pos.page = page + layout->start_page;
+	req.type = is_write ? NAND_PAGE_WRITE : NAND_PAGE_READ;
+	req.mode = MTD_OPS_RAW;
+	req.databuf.in = buf;
+
+	while (copied < len) {
+		req.datalen = min_t(unsigned int,
+				    otp_pagesize - req.dataoffs,
+				    len - copied);
+
+		if (is_write)
+			ret = spinand_write_page(spinand, &req);
+		else
+			ret = spinand_read_page(spinand, &req);
+
+		if (ret < 0)
+			break;
+
+		req.databuf.in += req.datalen;
+		req.pos.page++;
+		req.dataoffs = 0;
+		copied += req.datalen;
+	}
+
+	*retlen = copied;
+
+	if (spinand_upd_cfg(spinand, CFG_OTP_ENABLE, 0)) {
+		dev_warn(&spinand_to_mtd(spinand)->dev,
+			 "Can not disable OTP mode\n");
+		ret = -EIO;
+	}
+
+	return ret;
+}
+
+/**
+ * spinand_fact_otp_read() - Read from OTP area
+ * @spinand: the spinand device
+ * @ofs: the offset to read
+ * @len: the number of data bytes to read
+ * @retlen: the pointer to variable to store the number of read bytes
+ * @buf: the buffer to store the read data
+ *
+ * Return: 0 on success, an error code otherwise.
+ */
+int spinand_fact_otp_read(struct spinand_device *spinand, loff_t ofs,
+			  size_t len, size_t *retlen, u8 *buf)
+{
+	return spinand_otp_rw(spinand, ofs, len, retlen, buf, false,
+			      &spinand->fact_otp->layout);
+}
+
+/**
+ * spinand_user_otp_read() - Read from OTP area
+ * @spinand: the spinand device
+ * @ofs: the offset to read
+ * @len: the number of data bytes to read
+ * @retlen: the pointer to variable to store the number of read bytes
+ * @buf: the buffer to store the read data
+ *
+ * Return: 0 on success, an error code otherwise.
+ */
+int spinand_user_otp_read(struct spinand_device *spinand, loff_t ofs,
+			  size_t len, size_t *retlen, u8 *buf)
+{
+	return spinand_otp_rw(spinand, ofs, len, retlen, buf, false,
+			      &spinand->user_otp->layout);
+}
+
+/**
+ * spinand_user_otp_write() - Write to OTP area
+ * @spinand:  the spinand device
+ * @ofs: the offset to write to
+ * @len: the number of bytes to write
+ * @retlen: the pointer to variable to store the number of written bytes
+ * @buf: the buffer with data to write
+ *
+ * Return: 0 on success, an error code otherwise.
+ */
+int spinand_user_otp_write(struct spinand_device *spinand, loff_t ofs,
+			   size_t len, size_t *retlen, const u8 *buf)
+{
+	return spinand_otp_rw(spinand, ofs, len, retlen, (u8 *)buf, true,
+			      &spinand->user_otp->layout);
+}
+
 static int spinand_mtd_otp_info(struct mtd_info *mtd, size_t len,
 				size_t *retlen, struct otp_info *buf,
 				bool is_fact)
diff --git a/include/linux/mtd/spinand.h b/include/linux/mtd/spinand.h
index 597d28339d15..73424405232a 100644
--- a/include/linux/mtd/spinand.h
+++ b/include/linux/mtd/spinand.h
@@ -689,6 +689,13 @@ size_t spinand_otp_page_size(struct spinand_device *spinand);
 size_t spinand_fact_otp_size(struct spinand_device *spinand);
 size_t spinand_user_otp_size(struct spinand_device *spinand);
 
+int spinand_fact_otp_read(struct spinand_device *spinand, loff_t ofs,
+			  size_t len, size_t *retlen, u8 *buf);
+int spinand_user_otp_read(struct spinand_device *spinand, loff_t ofs,
+			  size_t len, size_t *retlen, u8 *buf);
+int spinand_user_otp_write(struct spinand_device *spinand, loff_t ofs,
+			   size_t len, size_t *retlen, const u8 *buf);
+
 int spinand_set_mtd_otp_ops(struct spinand_device *spinand);
 
 #endif /* __LINUX_MTD_SPINAND_H */