Patch "mtd: nand: brcmnand: Disable prefetch by default" has been added to the 4.4-stable tree

Patch "mtd: nand: brcmnand: Disable prefetch by default" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    mtd: nand: brcmnand: Disable prefetch by default

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mtd-nand-brcmnand-disable-prefetch-by-default.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From f953f0f89663c39f08f4baaa8a4a881401b65654 Mon Sep 17 00:00:00 2001
From: Kamal Dasu <kdasu.kdev@gmail.com>
Date: Mon, 8 Jan 2018 15:36:48 -0500
Subject: mtd: nand: brcmnand: Disable prefetch by default

From: Kamal Dasu <kdasu.kdev@gmail.com>

commit f953f0f89663c39f08f4baaa8a4a881401b65654 upstream.

Brcm nand controller prefetch feature needs to be disabled
by default. Enabling affects performance on random reads as
well as dma reads.

Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
Fixes: 27c5b17cd1b1 ("mtd: nand: add NAND driver "library" for Broadcom STB NAND controller")
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/mtd/nand/brcmnand/brcmnand.c |   13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

--- a/drivers/mtd/nand/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/brcmnand/brcmnand.c
@@ -1922,16 +1922,9 @@ static int brcmnand_setup_dev(struct brc
 	tmp &= ~ACC_CONTROL_PARTIAL_PAGE;
 	tmp &= ~ACC_CONTROL_RD_ERASED;
 	tmp &= ~ACC_CONTROL_FAST_PGM_RDIN;
-	if (ctrl->features & BRCMNAND_HAS_PREFETCH) {
-		/*
-		 * FIXME: Flash DMA + prefetch may see spurious erased-page ECC
-		 * errors
-		 */
-		if (has_flash_dma(ctrl))
-			tmp &= ~ACC_CONTROL_PREFETCH;
-		else
-			tmp |= ACC_CONTROL_PREFETCH;
-	}
+	if (ctrl->features & BRCMNAND_HAS_PREFETCH)
+		tmp &= ~ACC_CONTROL_PREFETCH;
+
 	nand_writereg(ctrl, offs, tmp);
 
 	return 0;


Patches currently in stable-queue which might be from kdasu.kdev@gmail.com are

queue-4.4/mtd-nand-brcmnand-disable-prefetch-by-default.patch