From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qt0-x241.google.com ([2607:f8b0:400d:c0d::241]) by bombadil.infradead.org with esmtps (Exim 4.89 #1 (Red Hat Linux)) id 1eYdhW-0006fc-Rd for linux-mtd@lists.infradead.org; Mon, 08 Jan 2018 20:07:20 +0000 Received: by mail-qt0-x241.google.com with SMTP id m59so15159768qte.11 for ; Mon, 08 Jan 2018 12:07:07 -0800 (PST) From: Kamal Dasu To: boris.brezillon@free-electrons.com, linux-mtd@lists.infradead.org, bcm-kernel-feedback-list@broadcom.com Cc: computersforpeace@gmail.com, richard@nod.at, dwmw2@infradead.org, marek.vasut@gmail.com, cyrille.pitchen@wedev4u.fr, Kamal Dasu , stable@vger.kernel.org Subject: [PATCH v2] mtd: nand: brcmnand: Disable prefetch by default Date: Mon, 8 Jan 2018 15:06:13 -0500 Message-Id: <1515441973-30753-1-git-send-email-kdasu.kdev@gmail.com> List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 Cc: stable@vger.kernel.org --- drivers/mtd/nand/brcmnand/brcmnand.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c index dd56a67..2a978d9 100644 --- a/drivers/mtd/nand/brcmnand/brcmnand.c +++ b/drivers/mtd/nand/brcmnand/brcmnand.c @@ -2193,16 +2193,9 @@ static int brcmnand_setup_dev(struct brcmnand_host *host) 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; -- 2.7.4