[ 3.5.y.z extended stable ] Patch "mtd: nand: gpmi: reset BCH earlier, too, to avoid NAND" has been added to staging queue

[Herton Ronaldo Krzesinski]

This is a note to let you know that I have just added a patch titled

    mtd: nand: gpmi: reset BCH earlier, too, to avoid NAND

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Herton

------

>From 0c53ae50dd4dece16329cb23d7ba1f1bea0d0aed Mon Sep 17 00:00:00 2001
From: Wolfram Sang <w.sang at pengutronix.de>
Date: Wed, 5 Dec 2012 21:46:02 +0100
Subject: [PATCH 10/27] mtd: nand: gpmi: reset BCH earlier, too, to avoid NAND
 startup problems

commit 6f2a6a52560ad8d85710aabd92b7a3239b3a6b07 upstream.

It could happen (1 out of 100 times) that NAND did not start up
correctly after warm rebooting, so the kernel could not find the UBI or
DMA timed out due to a stalled BCH. When resetting BCH together with
GPMI, the issue could not be observed anymore (after 10000+ reboots). We
probably need the consistent state already before sending any command to
NAND, even when no ECC is needed. I chose to keep the extra reset for
BCH when changing the flash layout to be on the safe side.

Signed-off-by: Wolfram Sang <w.sang at pengutronix.de>
Acked-by: Huang Shijie <b32955 at freescale.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy at linux.intel.com>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
---
 drivers/mtd/nand/gpmi-nand/gpmi-lib.c |    9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
index a1f4332..b27e215 100644
--- a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
+++ b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
@@ -136,6 +136,15 @@ int gpmi_init(struct gpmi_nand_data *this)
 	if (ret)
 		goto err_out;

+	/*
+	 * Reset BCH here, too. We got failures otherwise :(
+	 * See later BCH reset for explanation of MX23 handling
+	 */
+	ret = gpmi_reset_block(r->bch_regs, GPMI_IS_MX23(this));
+	if (ret)
+		goto err_out;
+
+
 	/* Choose NAND mode. */
 	writel(BM_GPMI_CTRL1_GPMI_MODE, r->gpmi_regs + HW_GPMI_CTRL1_CLR);

--
1.7.9.5