From: Karl Beldan Date: Mon, 29 Aug 2016 07:45:49 +0000 (+0000) Subject: mtd: nand: davinci: Reinitialize the HW ECC engine in 4bit hwctl X-Git-Tag: firefly_0821_release~176^2~4^2~26^2~114 X-Git-Url: http://plrg.eecs.uci.edu/git/?p=firefly-linux-kernel-4.4.55.git;a=commitdiff_plain;h=05d721d61e75ec52e986af998ed145c54ed327fe mtd: nand: davinci: Reinitialize the HW ECC engine in 4bit hwctl commit f6d7c1b5598b6407c3f1da795dd54acf99c1990c upstream. This fixes subpage writes when using 4-bit HW ECC. There has been numerous reports about ECC errors with devices using this driver for a while. Also the 4-bit ECC has been reported as broken with subpages in [1] and with 16 bits NANDs in the driver and in mach* board files both in mainline and in the vendor BSPs. What I saw with 4-bit ECC on a 16bits NAND (on an LCDK) which got me to try reinitializing the ECC engine: - R/W on whole pages properly generates/checks RS code - try writing the 1st subpage only of a blank page, the subpage is well written and the RS code properly generated, re-reading the same page the HW detects some ECC error, reading the same page again no ECC error is detected Note that the ECC engine is already reinitialized in the 1-bit case. Tested on my LCDK with UBI+UBIFS using subpages. This could potentially get rid of the issue workarounded in [1]. [1] 28c015a9daab ("mtd: davinci-nand: disable subpage write for keystone-nand") Fixes: 6a4123e581b3 ("mtd: nand: davinci_nand, 4-bit ECC for smallpage") Signed-off-by: Karl Beldan Acked-by: Boris Brezillon Signed-off-by: Brian Norris Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/mtd/nand/davinci_nand.c b/drivers/mtd/nand/davinci_nand.c index c72313d66cf6..bc054a5ed7f8 100644 --- a/drivers/mtd/nand/davinci_nand.c +++ b/drivers/mtd/nand/davinci_nand.c @@ -241,6 +241,9 @@ static void nand_davinci_hwctl_4bit(struct mtd_info *mtd, int mode) unsigned long flags; u32 val; + /* Reset ECC hardware */ + davinci_nand_readl(info, NAND_4BIT_ECC1_OFFSET); + spin_lock_irqsave(&davinci_nand_lock, flags); /* Start 4-bit ECC calculation for read/write */