Do nand reset before write protect check
If we want to check the WP# low or high through STATUS READ and check bit 7,
we must reset the device, other operation (eg.erase/program a locked block) can
also clear the bit 7 of status register.
Signed-off-by: White Ding <b...@micron.com>
---
drivers/mtd/nand/nand_base.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 41167e9..22dd3aa 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -965,6 +965,15 @@ int nand_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t
len)
chip->select_chip(mtd, chipnr);
+ /*
+ * Reset the chip.
+ * If we want to check the WP through READ STATUS and check the bit 7
+ * we must reset the chip
+ * some operation can also clear the bit 7 of status register
+ * eg. erase/program a locked block
+ */
+ chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);
+
/* Check, if it is write protected */
if (nand_check_wp(mtd)) {
pr_debug("%s: device is write protected!\n",
@@ -1015,6 +1024,15 @@ int nand_lock(struct mtd_info *mtd, loff_t ofs, uint64_t
len)
chip->select_chip(mtd, chipnr);
+ /*
+ * Reset the chip.
+ * If we want to check the WP through READ STATUS and check the bit 7
+ * we must reset the chip
+ * some operation can also clear the bit 7 of status register
+ * eg. erase/program a locked block
+ */
+ chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);
+
/* Check, if it is write protected */
if (nand_check_wp(mtd)) {
pr_debug("%s: device is write protected!\n",
--
1.7.9.5
Br
White Ding
____________________________
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Mobile: 86-13761729112
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