From mboxrd@z Thu Jan 1 00:00:00 1970 From: Abhishek Sahu Subject: [PATCH 3/5] mtd: rawnand: qcom: fix NAND register write errors Date: Fri, 6 Jul 2018 13:21:57 +0530 Message-ID: <1530863519-5564-4-git-send-email-absahu@codeaurora.org> References: <1530863519-5564-1-git-send-email-absahu@codeaurora.org> Return-path: In-Reply-To: <1530863519-5564-1-git-send-email-absahu@codeaurora.org> Sender: linux-kernel-owner@vger.kernel.org To: Boris Brezillon , Miquel Raynal Cc: David Woodhouse , Brian Norris , Marek Vasut , Richard Weinberger , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, Andy Gross , Abhishek Sahu List-Id: linux-arm-msm@vger.kernel.org Fix the following NAND register write errors which will be generated if access protection is enabled. 1. SFLASHC_BURST_CFG register is not available for supported NAND contollers by this driver, so this can be removed. 2. NAND_CTRL is operational register and register writes to operational registers should always be done through command descriptors if BAM_MODE is already enabled. With full boot chain, bootloader already enables BAM_MODE so read the NAND_CTRL register value and write only if BAM_MODE is not set. Signed-off-by: Abhishek Sahu --- drivers/mtd/nand/raw/qcom_nandc.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c index df12cf3..9e6b383 100644 --- a/drivers/mtd/nand/raw/qcom_nandc.c +++ b/drivers/mtd/nand/raw/qcom_nandc.c @@ -2693,15 +2693,20 @@ static int qcom_nandc_setup(struct qcom_nand_controller *nandc) { u32 nand_ctrl; - /* kill onenand */ - nandc_write(nandc, SFLASHC_BURST_CFG, 0); nandc_write(nandc, dev_cmd_reg_addr(nandc, NAND_DEV_CMD_VLD), NAND_DEV_CMD_VLD_VAL); /* enable ADM or BAM DMA */ if (nandc->props->is_bam) { nand_ctrl = nandc_read(nandc, NAND_CTRL); - nandc_write(nandc, NAND_CTRL, nand_ctrl | BAM_MODE_EN); + /* + * Once BAM_MODE_EN bit is set then QPIC_NAND_CTRL register + * should be written with BAM instead of writel. + * Check if BAM_MODE_EN is already set by bootloader and write + * only if this bit is not set. + */ + if (!(nand_ctrl & BAM_MODE_EN)) + nandc_write(nandc, NAND_CTRL, nand_ctrl | BAM_MODE_EN); } else { nandc_write(nandc, NAND_FLASH_CHIP_SELECT, DM_EN); } -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation