[RFC] mtd: nand: Add a STATUS CMD after write verification

[Bastian Hecht <hechtb@googlemail.com>]

When using CONFIG_MTD_NAND_VERIFY_WRITE=y an extra read command is sent
to the NAND chip after writing a page. We need an extra status command
to avoid hick-ups that lead to page write failures.
---

Hello all,

I'm experiencing problems with my current setup and
CONFIG_MTD_NAND_VERIFY_WRITE=y. Usually the command sequence is like
0x70 		Status read
0x80 0x10 	Page prog
0x70
0x80 0x10 	Page prog
0x70
...

When activating write verification there is a read command before the
page prog.
0x80 0x10
0x70
0x0		read
0x80 0x10
0x70
...
This makes my chip write garbage, while the patch fixes it.
Now I wonder if this problem is caused by my NAND chip only, or if this
is a general problem that should be adressed.
---
 drivers/mtd/nand/nand_base.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 8a393f9..62d6691 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -2101,6 +2101,8 @@ static int nand_write_page(struct mtd_info *mtd, struct nand_chip *chip,
 
 	if (chip->verify_buf(mtd, buf, mtd->writesize))
 		return -EIO;
+	
+	chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);
 #endif
 	return 0;
 }
-- 
1.7.5.4