Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751637AbdHPItF (ORCPT ); Wed, 16 Aug 2017 04:49:05 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:38084 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751082AbdHPItD (ORCPT ); Wed, 16 Aug 2017 04:49:03 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Wed, 16 Aug 2017 14:19:01 +0530 From: Abhishek Sahu To: Archit Taneja Cc: boris.brezillon@free-electrons.com, dwmw2@infradead.org, computersforpeace@gmail.com, marek.vasut@gmail.com, richard@nod.at, cyrille.pitchen@wedev4u.fr, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, devicetree@vger.kernel.org, andy.gross@linaro.org, sricharan@codeaurora.org Subject: Re: [PATCH v4 11/20] mtd: nand: qcom: enable BAM or ADM mode In-Reply-To: References: <1502451575-15712-1-git-send-email-absahu@codeaurora.org> <1502451575-15712-12-git-send-email-absahu@codeaurora.org> Message-ID: User-Agent: Roundcube Webmail/1.2.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3061 Lines: 81 On 2017-08-16 10:20, Archit Taneja wrote: > On 08/11/2017 05:09 PM, Abhishek Sahu wrote: >> 1. DM_EN is only required for EBI2 NAND controller which uses ADM >> 2. BAM mode will be disabled after power on reset which needs to >> be enabled before starting any BAM transfers. >> >> Signed-off-by: Abhishek Sahu >> --- >> drivers/mtd/nand/qcom_nandc.c | 17 ++++++++++++++--- >> 1 file changed, 14 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/mtd/nand/qcom_nandc.c >> b/drivers/mtd/nand/qcom_nandc.c >> index 3d9fd7f..ae873d3 100644 >> --- a/drivers/mtd/nand/qcom_nandc.c >> +++ b/drivers/mtd/nand/qcom_nandc.c >> @@ -163,6 +163,9 @@ >> #define NAND_DEV_CMD_VLD_VAL (READ_START_VLD | WRITE_START_VLD | \ >> ERASE_START_VLD | SEQ_READ_START_VLD) >> +/* NAND_CTRL bits */ >> +#define BAM_MODE_EN BIT(0) >> + >> /* >> * the NAND controller performs reads/writes with ECC in 516 byte >> chunks. >> * the driver calls the chunks 'step' or 'codeword' interchangeably >> @@ -1035,7 +1038,8 @@ static int read_id(struct qcom_nand_host *host, >> int column) >> nandc_set_reg(nandc, NAND_FLASH_CMD, FETCH_ID); >> nandc_set_reg(nandc, NAND_ADDR0, column); >> nandc_set_reg(nandc, NAND_ADDR1, 0); >> - nandc_set_reg(nandc, NAND_FLASH_CHIP_SELECT, DM_EN); >> + nandc_set_reg(nandc, NAND_FLASH_CHIP_SELECT, >> + nandc->props->is_bam ? 0 : DM_EN); > > I'm not sure why the above register was configured in read_id in the > first place. Would > it be required later if we want the controller to support multiple > NAND chips? If not, > then we could consider dropping this. Anyway, that can be posted as a > separate patch > later. Correct. It seems the current driver does not have fully support second NAND chip select since it need to program NAND_DEV1_CFG1 and NAND_DEV1_CFG0 also. We can have separate patch series which will add the full support for multiple NAND chips and this line can be removed in that patch series. > > Reviewed-by: Archit Taneja > > Thanks, > Archit > >> nandc_set_reg(nandc, NAND_EXEC_CMD, 1); >> write_reg_dma(nandc, NAND_FLASH_CMD, 4, NAND_BAM_NEXT_SGL); >> @@ -2408,12 +2412,19 @@ static void qcom_nandc_unalloc(struct >> qcom_nand_controller *nandc) >> /* one time setup of a few nand controller registers */ >> 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, NAND_DEV_CMD_VLD, NAND_DEV_CMD_VLD_VAL); >> - /* enable ADM DMA */ >> - nandc_write(nandc, NAND_FLASH_CHIP_SELECT, DM_EN); >> + /* 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); >> + } else { >> + nandc_write(nandc, NAND_FLASH_CHIP_SELECT, DM_EN); >> + } >> /* save the original values of these registers */ >> nandc->cmd1 = nandc_read(nandc, NAND_DEV_CMD1); >>