Messages in this thread Patch in this message | | | From | bpqw <> | Subject | Subject: [PATCH 1/1] mtd:nand:fix nand_lock/unlock() function | Date | Thu, 24 Jul 2014 01:00:01 +0000 |
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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 <bpqw@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 ____________________________ EBU APAC Application Engineering Tel:86-21-38997078 Mobile: 86-13761729112 Address: No 601 Fasai Rd, Waigaoqiao Free Trade Zone Pudong, Shanghai, China
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