1 files changed, 145 insertions, 15 deletions

diff --git a/drivers/mtd/spi-nor/otp.c b/drivers/mtd/spi-nor/otp.c
index fcf38d260345..983e40b19134 100644
--- a/drivers/mtd/spi-nor/otp.c
+++ b/drivers/mtd/spi-nor/otp.c
@@ -15,14 +15,21 @@
 #define spi_nor_otp_n_regions(nor) ((nor)->params->otp.org->n_regions)
 
 /**
- * spi_nor_otp_read_secr() - read OTP data
+ * spi_nor_otp_read_secr() - read security register
  * @nor:	pointer to 'struct spi_nor'
- * @from:       offset to read from
+ * @addr:       offset to read from
  * @len:        number of bytes to read
  * @buf:        pointer to dst buffer
  *
- * Read OTP data from one region by using the SPINOR_OP_RSECR commands. This
- * method is used on GigaDevice and Winbond flashes.
+ * Read a security register by using the SPINOR_OP_RSECR commands.
+ *
+ * In Winbond/GigaDevice datasheets the term "security register" stands for
+ * an one-time-programmable memory area, consisting of multiple bytes (usually
+ * 256). Thus one "security register" maps to one OTP region.
+ *
+ * This method is used on GigaDevice and Winbond flashes.
+ *
+ * Please note, the read must not span multiple registers.
  *
  * Return: number of bytes read successfully, -errno otherwise
  */
@@ -40,7 +47,6 @@ int spi_nor_otp_read_secr(struct spi_nor *nor, loff_t addr, size_t len, u8 *buf)
 	rdesc = nor->dirmap.rdesc;
 
 	nor->read_opcode = SPINOR_OP_RSECR;
-	nor->addr_width = 3;
 	nor->read_dummy = 8;
 	nor->read_proto = SNOR_PROTO_1_1_1;
 	nor->dirmap.rdesc = NULL;
@@ -57,16 +63,20 @@ int spi_nor_otp_read_secr(struct spi_nor *nor, loff_t addr, size_t len, u8 *buf)
 }
 
 /**
- * spi_nor_otp_write_secr() - write OTP data
+ * spi_nor_otp_write_secr() - write security register
  * @nor:        pointer to 'struct spi_nor'
- * @to:         offset to write to
+ * @addr:       offset to write to
  * @len:        number of bytes to write
  * @buf:        pointer to src buffer
  *
- * Write OTP data to one region by using the SPINOR_OP_PSECR commands. This
- * method is used on GigaDevice and Winbond flashes.
+ * Write a security register by using the SPINOR_OP_PSECR commands.
+ *
+ * For more information on the term "security register", see the documentation
+ * of spi_nor_otp_read_secr().
  *
- * Please note, the write must not span multiple OTP regions.
+ * This method is used on GigaDevice and Winbond flashes.
+ *
+ * Please note, the write must not span multiple registers.
  *
  * Return: number of bytes written successfully, -errno otherwise
  */
@@ -84,13 +94,12 @@ int spi_nor_otp_write_secr(struct spi_nor *nor, loff_t addr, size_t len,
 	wdesc = nor->dirmap.wdesc;
 
 	nor->program_opcode = SPINOR_OP_PSECR;
-	nor->addr_width = 3;
 	nor->write_proto = SNOR_PROTO_1_1_1;
 	nor->dirmap.wdesc = NULL;
 
 	/*
 	 * We only support a write to one single page. For now all winbond
-	 * flashes only have one page per OTP region.
+	 * flashes only have one page per security register.
 	 */
 	ret = spi_nor_write_enable(nor);
 	if (ret)
@@ -111,6 +120,38 @@ out:
 	return ret ?: written;
 }
 
+/**
+ * spi_nor_otp_erase_secr() - erase a security register
+ * @nor:        pointer to 'struct spi_nor'
+ * @addr:       offset of the security register to be erased
+ *
+ * Erase a security register by using the SPINOR_OP_ESECR command.
+ *
+ * For more information on the term "security register", see the documentation
+ * of spi_nor_otp_read_secr().
+ *
+ * This method is used on GigaDevice and Winbond flashes.
+ *
+ * Return: 0 on success, -errno otherwise
+ */
+int spi_nor_otp_erase_secr(struct spi_nor *nor, loff_t addr)
+{
+	u8 erase_opcode = nor->erase_opcode;
+	int ret;
+
+	ret = spi_nor_write_enable(nor);
+	if (ret)
+		return ret;
+
+	nor->erase_opcode = SPINOR_OP_ESECR;
+	ret = spi_nor_erase_sector(nor, addr);
+	nor->erase_opcode = erase_opcode;
+	if (ret)
+		return ret;
+
+	return spi_nor_wait_till_ready(nor);
+}
+
 static int spi_nor_otp_lock_bit_cr(unsigned int region)
 {
 	static const int lock_bits[] = { SR2_LB1, SR2_LB2, SR2_LB3 };
@@ -240,6 +281,29 @@ out:
 	return ret;
 }
 
+static int spi_nor_mtd_otp_range_is_locked(struct spi_nor *nor, loff_t ofs,
+					   size_t len)
+{
+	const struct spi_nor_otp_ops *ops = nor->params->otp.ops;
+	unsigned int region;
+	int locked;
+
+	/*
+	 * If any of the affected OTP regions are locked the entire range is
+	 * considered locked.
+	 */
+	for (region = spi_nor_otp_offset_to_region(nor, ofs);
+	     region <= spi_nor_otp_offset_to_region(nor, ofs + len - 1);
+	     region++) {
+		locked = ops->is_locked(nor, region);
+		/* take the branch it is locked or in case of an error */
+		if (locked)
+			return locked;
+	}
+
+	return 0;
+}
+
 static int spi_nor_mtd_otp_read_write(struct mtd_info *mtd, loff_t ofs,
 				      size_t total_len, size_t *retlen,
 				      const u8 *buf, bool is_write)
@@ -255,14 +319,26 @@ static int spi_nor_mtd_otp_read_write(struct mtd_info *mtd, loff_t ofs,
 	if (ofs < 0 || ofs >= spi_nor_otp_size(nor))
 		return 0;
 
+	/* don't access beyond the end */
+	total_len = min_t(size_t, total_len, spi_nor_otp_size(nor) - ofs);
+
+	if (!total_len)
+		return 0;
+
 	ret = spi_nor_lock_and_prep(nor);
 	if (ret)
 		return ret;
 
-	/* don't access beyond the end */
-	total_len = min_t(size_t, total_len, spi_nor_otp_size(nor) - ofs);
+	if (is_write) {
+		ret = spi_nor_mtd_otp_range_is_locked(nor, ofs, total_len);
+		if (ret < 0) {
+			goto out;
+		} else if (ret) {
+			ret = -EROFS;
+			goto out;
+		}
+	}
 
-	*retlen = 0;
 	while (total_len) {
 		/*
 		 * The OTP regions are mapped into a contiguous area starting
@@ -316,6 +392,59 @@ static int spi_nor_mtd_otp_write(struct mtd_info *mtd, loff_t to, size_t len,
 	return spi_nor_mtd_otp_read_write(mtd, to, len, retlen, buf, true);
 }
 
+static int spi_nor_mtd_otp_erase(struct mtd_info *mtd, loff_t from, size_t len)
+{
+	struct spi_nor *nor = mtd_to_spi_nor(mtd);
+	const struct spi_nor_otp_ops *ops = nor->params->otp.ops;
+	const size_t rlen = spi_nor_otp_region_len(nor);
+	unsigned int region;
+	loff_t rstart;
+	int ret;
+
+	/* OTP erase is optional */
+	if (!ops->erase)
+		return -EOPNOTSUPP;
+
+	if (!len)
+		return 0;
+
+	if (from < 0 || (from + len) > spi_nor_otp_size(nor))
+		return -EINVAL;
+
+	/* the user has to explicitly ask for whole regions */
+	if (!IS_ALIGNED(len, rlen) || !IS_ALIGNED(from, rlen))
+		return -EINVAL;
+
+	ret = spi_nor_lock_and_prep(nor);
+	if (ret)
+		return ret;
+
+	ret = spi_nor_mtd_otp_range_is_locked(nor, from, len);
+	if (ret < 0) {
+		goto out;
+	} else if (ret) {
+		ret = -EROFS;
+		goto out;
+	}
+
+	while (len) {
+		region = spi_nor_otp_offset_to_region(nor, from);
+		rstart = spi_nor_otp_region_start(nor, region);
+
+		ret = ops->erase(nor, rstart);
+		if (ret)
+			goto out;
+
+		len -= rlen;
+		from += rlen;
+	}
+
+out:
+	spi_nor_unlock_and_unprep(nor);
+
+	return ret;
+}
+
 static int spi_nor_mtd_otp_lock(struct mtd_info *mtd, loff_t from, size_t len)
 {
 	struct spi_nor *nor = mtd_to_spi_nor(mtd);
@@ -374,4 +503,5 @@ void spi_nor_otp_init(struct spi_nor *nor)
 	mtd->_read_user_prot_reg = spi_nor_mtd_otp_read;
 	mtd->_write_user_prot_reg = spi_nor_mtd_otp_write;
 	mtd->_lock_user_prot_reg = spi_nor_mtd_otp_lock;
+	mtd->_erase_user_prot_reg = spi_nor_mtd_otp_erase;
 }