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 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: mtd-nand-brcmnand-disable-prefetch-by-default.patch and it can be found in the queue-4.9 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 @@ -2193,16 +2193,9 @@ static int brcmnand_setup_dev(struct brc if (ctrl->nand_version >= 0x0702) 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-4.9/mtd-nand-brcmnand-disable-prefetch-by-default.patch