[PATCH v2 4/5] mtd: spinand: micron: OTP access for MT29F2G01ABAGD

[Martin Kurbanov]

Support for OTP area access on Micron MT29F2G01ABAGD chip.

Signed-off-by: Martin Kurbanov <mmkurbanov@xxxxxxxxxxxxxxxxx>
---
 drivers/mtd/nand/spi/micron.c | 117 +++++++++++++++++++++++++++++++++-
 1 file changed, 116 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/spi/micron.c b/drivers/mtd/nand/spi/micron.c
index 8d741be6d5f3e..a538409db4ccd 100644
--- a/drivers/mtd/nand/spi/micron.c
+++ b/drivers/mtd/nand/spi/micron.c
@@ -9,6 +9,7 @@
 #include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/mtd/spinand.h>
+#include <linux/spi/spi-mem.h>
 
 #define SPINAND_MFR_MICRON		0x2c
 
@@ -28,6 +29,16 @@
 
 #define MICRON_SELECT_DIE(x)	((x) << 6)
 
+#define MICRON_MT29F2G01ABAGD_OTP_PAGES			12
+#define MICRON_MT29F2G01ABAGD_OTP_PAGE_SIZE		2176
+#define MICRON_MT29F2G01ABAGD_OTP_SIZE_BYTES		\
+	(MICRON_MT29F2G01ABAGD_OTP_PAGES *		\
+	 MICRON_MT29F2G01ABAGD_OTP_PAGE_SIZE)
+
+#define MICRON_MT29F2G01ABAGD_CFG_OTP_STATE		BIT(7)
+#define MICRON_MT29F2G01ABAGD_CFG_OTP_LOCK		\
+	(CFG_OTP_ENABLE | MICRON_MT29F2G01ABAGD_CFG_OTP_STATE)
+
 static SPINAND_OP_VARIANTS(quadio_read_cache_variants,
 		//SPINAND_PAGE_READ_FROM_CACHE_QUADIO_OP(0, 2, NULL, 0),
 		SPINAND_PAGE_READ_FROM_CACHE_X4_OP(0, 1, NULL, 0),
@@ -182,6 +193,108 @@ static int micron_8_ecc_get_status(struct spinand_device *spinand,
 	return -EINVAL;
 }
 
+static int mt29f2g01abagd_otp_is_locked(struct spinand_device *spinand)
+{
+	size_t buf_size = MICRON_MT29F2G01ABAGD_OTP_PAGE_SIZE;
+	size_t retlen;
+	u8 *buf;
+	int ret;
+
+	buf = kmalloc(buf_size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	ret = spinand_upd_cfg(spinand,
+			      MICRON_MT29F2G01ABAGD_CFG_OTP_LOCK,
+			      MICRON_MT29F2G01ABAGD_CFG_OTP_STATE);
+	if (ret)
+		goto out;
+
+	ret = spinand_otp_read(spinand, 0, buf_size, buf, &retlen);
+
+	if (spinand_upd_cfg(spinand, MICRON_MT29F2G01ABAGD_CFG_OTP_LOCK,
+			    0)) {
+		WARN(1, "Can not disable OTP mode\n");
+		ret = -EIO;
+	}
+
+	if (!ret) {
+		size_t i = 0;
+
+		/* If all zeros, then the OTP area is locked. */
+		while (i < buf_size && *(uint32_t *)(&buf[i]) == 0)
+			i += 4;
+
+		if (i == buf_size)
+			ret = 1;
+	}
+
+out:
+	kfree(buf);
+	return ret;
+}
+
+static int mt29f2g01abagd_otp_info(struct spinand_device *spinand, size_t len,
+				   struct otp_info *buf, size_t *retlen)
+{
+	int locked;
+
+	if (len < sizeof(*buf))
+		return -EINVAL;
+
+	locked = mt29f2g01abagd_otp_is_locked(spinand);
+	if (locked < 0)
+		return locked;
+
+	buf->locked = locked;
+	buf->start = 0;
+	buf->length = MICRON_MT29F2G01ABAGD_OTP_SIZE_BYTES;
+
+	*retlen = sizeof(*buf);
+	return 0;
+}
+
+static int mt29f2g01abagd_otp_lock(struct spinand_device *spinand, loff_t from,
+				   size_t len)
+{
+	struct spi_mem_op write_op = SPINAND_WR_EN_DIS_OP(true);
+	struct spi_mem_op exec_op = SPINAND_PROG_EXEC_OP(0);
+	int ret;
+
+	ret = spinand_upd_cfg(spinand,
+			      MICRON_MT29F2G01ABAGD_CFG_OTP_LOCK,
+			      MICRON_MT29F2G01ABAGD_CFG_OTP_LOCK);
+	if (!ret)
+		return ret;
+
+	ret = spi_mem_exec_op(spinand->spimem, &write_op);
+	if (!ret)
+		goto out;
+
+	ret = spi_mem_exec_op(spinand->spimem, &exec_op);
+	if (!ret)
+		goto out;
+
+	ret = spinand_wait(spinand, 10, 5, NULL);
+	if (!ret)
+		goto out;
+
+out:
+	if (spinand_upd_cfg(spinand, MICRON_MT29F2G01ABAGD_CFG_OTP_LOCK, 0)) {
+		WARN(1, "Can not disable OTP mode\n");
+		ret = -EIO;
+	}
+
+	return ret;
+}
+
+static const struct spinand_otp_ops mt29f2g01abagd_otp_ops = {
+	.info = mt29f2g01abagd_otp_info,
+	.lock = mt29f2g01abagd_otp_lock,
+	.read = spinand_otp_read,
+	.write = spinand_otp_write,
+};
+
 static const struct spinand_info micron_spinand_table[] = {
 	/* M79A 2Gb 3.3V */
 	SPINAND_INFO("MT29F2G01ABAGD",
@@ -193,7 +306,9 @@ static const struct spinand_info micron_spinand_table[] = {
 					      &x4_update_cache_variants),
 		     0,
 		     SPINAND_ECCINFO(&micron_8_ooblayout,
-				     micron_8_ecc_get_status)),
+				     micron_8_ecc_get_status),
+		     SPINAND_OTP_INFO(MICRON_MT29F2G01ABAGD_OTP_PAGES,
+				      &mt29f2g01abagd_otp_ops)),
 	/* M79A 2Gb 1.8V */
 	SPINAND_INFO("MT29F2G01ABBGD",
 		     SPINAND_ID(SPINAND_READID_METHOD_OPCODE_DUMMY, 0x25),
-- 
2.43.2