From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 61DD2C433DF for ; Tue, 9 Jun 2020 11:11:19 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 33334207F9 for ; Tue, 9 Jun 2020 11:11:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="k5lWIu1c" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 33334207F9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:List-Subscribe:List-Help: List-Post:List-Archive:List-Unsubscribe:List-Id:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Cc:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ri2Lt6+YvTlNMiqfnTu4hX6SfKpc7qAJZe15CDGyu/k=; b=k5lWIu1c8RWuxP XVFnPIxlxgLOmb7IYhKf2tM1LSc9fEw1p5lSTKO1aPL1aJe64ufOZm0Yz8nu5QFZRugMt6T0ZY5Tz F+zdPGeiUdQ+mQn38w1ewIDNeNhTGUCLBV1WO/NlJkQaLDagnC9c/4n8JmizUaLwZ2UrzKZLI6AE9 yUwDS2EeUNT0Bx8GuwCFBhNLfYkTS3oPeNliqnWINm07AKbpbKDHojr1Rwg+iID4+iUbwgmw4+0Tg GYTA0qQGcQyM65gabFtrI866SZvM9pNLTKSkP6BoRd5es9DUSmxg3zgqzP82WLvY+Cs2kYSTGN2LN MsdlpQ7AZvgZ1MtYLdqg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jic9s-0002jK-P4; Tue, 09 Jun 2020 11:11:08 +0000 Received: from alexa-out-sd-01.qualcomm.com ([199.106.114.38]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jic9q-0002i7-4a for linux-mtd@lists.infradead.org; Tue, 09 Jun 2020 11:11:07 +0000 Received: from unknown (HELO ironmsg03-sd.qualcomm.com) ([10.53.140.143]) by alexa-out-sd-01.qualcomm.com with ESMTP; 09 Jun 2020 04:11:04 -0700 Received: from sivaprak-linux.qualcomm.com ([10.201.3.202]) by ironmsg03-sd.qualcomm.com with ESMTP; 09 Jun 2020 04:11:02 -0700 Received: by sivaprak-linux.qualcomm.com (Postfix, from userid 459349) id CEAA221874; Tue, 9 Jun 2020 16:41:00 +0530 (IST) From: Sivaprakash Murugesan To: miquel.raynal@bootlin.com, richard@nod.at, vigneshr@ti.com, peter.ujfalusi@ti.com, sivaprak@codeaurora.org, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH V2 2/2] mtd: rawnand: qcom: set BAM mode only if not set already Date: Tue, 9 Jun 2020 16:40:56 +0530 Message-Id: <1591701056-3944-3-git-send-email-sivaprak@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1591701056-3944-1-git-send-email-sivaprak@codeaurora.org> References: <1591701056-3944-1-git-send-email-sivaprak@codeaurora.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200609_041106_205477_D6E7B227 X-CRM114-Status: UNSURE ( 9.18 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org BAM mode is set by writing BAM_MODE_EN bit on NAND_CTRL register. NAND_CTRL is an operational register and in BAM mode operational registers are read only. So, before writing into NAND_CTRL register check if BAM mode is already enabled by bootloader, and set BAM mode only if it is not set already. Signed-off-by: Sivaprakash Murugesan --- drivers/mtd/nand/raw/qcom_nandc.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c index e0afa2c..7740059 100644 --- a/drivers/mtd/nand/raw/qcom_nandc.c +++ b/drivers/mtd/nand/raw/qcom_nandc.c @@ -2779,7 +2779,14 @@ static int qcom_nandc_setup(struct qcom_nand_controller *nandc) /* 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); + /* NAND_CTRL is an operational registers, and CPU + * access to operational registers are read only + * in BAM mode. So update the NAND_CTRL register + * only if it is not in BAM mode. In most cases BAM + * mode will be enabled in bootloader + */ + 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); } -- 2.7.4 ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/