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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E1D5DC433F5 for ; Mon, 3 Jan 2022 05:52:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229883AbiACFwD (ORCPT ); Mon, 3 Jan 2022 00:52:03 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:44166 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229876AbiACFwD (ORCPT ); Mon, 3 Jan 2022 00:52:03 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 24951B80989 for ; Mon, 3 Jan 2022 05:52:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8DA07C36AEB; Mon, 3 Jan 2022 05:51:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1641189120; bh=Rvdd71uzdWwOSe7+yhScwEDQuAfW55HrUBLeHi9rhPs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LgPw8OWSLgkN3lCpvTt0bPlghy/ha3PBlcersBkE6W5gJcH0sGdkfbrmvnGLNya4Z 51AKmPdvdoi/K26sqv61xKvvEUw4o4eeFot+19srcfFecq40QNrHInGG6xeglVaGFr C37FY5H61YDbOEuYxcLytKNMWQ0sRbrR5FiezeV3riMxlyML+d9pcwR2UiJwmuOGF/ Rb2V7sbMLbRy8fRh4fIUFlOUR4Gs7vdanLA8RkUwdoVMtkpsy/HyXdhf2hOeqDtiAk OOK6Hmjpw6/amQEYtdYIwMrM17q3tDXk5ABFq86tDopud6W1yNiL25pY7VdSjW4uvT ds/KL7TMUKN9g== Date: Mon, 3 Jan 2022 11:21:52 +0530 From: Manivannan Sadhasivam To: Bryan O'Donoghue Cc: linux-arm-msm@vger.kernel.org, linux-mtd@lists.infradead.org, miquel.raynal@bootlin.com, architt@codeaurora.org, bbrezillon@kernel.org, absahu@codeaurora.org, baruch@tkos.co.il Subject: Re: [PATCH v2 1/2] mtd: rawnand: qcom: Fix clock sequencing in qcom_nandc_probe() Message-ID: <20220103055152.GA3581@thinkpad> References: <20220103030316.58301-1-bryan.odonoghue@linaro.org> <20220103030316.58301-2-bryan.odonoghue@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220103030316.58301-2-bryan.odonoghue@linaro.org> Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Mon, Jan 03, 2022 at 03:03:15AM +0000, Bryan O'Donoghue wrote: > Interacting with a NAND chip on an IPQ6018 I found that the qcomsmem NAND > partition parser was returning -EPROBE_DEFER waiting for the main smem > driver to load. > > This caused the board to reset. Playing about with the probe() function > shows that the problem lies in the core clock being switched off before the > nandc_unalloc() routine has completed. > > If we look at how qcom_nandc_remove() tears down allocated resources we see > the expected order is > > qcom_nandc_unalloc(nandc); > > clk_disable_unprepare(nandc->aon_clk); > clk_disable_unprepare(nandc->core_clk); > > dma_unmap_resource(&pdev->dev, nandc->base_dma, resource_size(res), > DMA_BIDIRECTIONAL, 0); > > Tweaking probe() to both bring up and tear-down in that order removes the > reset if we end up deferring elsewhere. > > Fixes: c76b78d8ec05 ("mtd: nand: Qualcomm NAND controller driver") > Signed-off-by: Bryan O'Donoghue Reviewed-by: Manivannan Sadhasivam Can you please CC stable list for backporting? Thanks, Mani > --- > drivers/mtd/nand/raw/qcom_nandc.c | 14 ++++++-------- > 1 file changed, 6 insertions(+), 8 deletions(-) > > diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c > index 04e6f7b267064..0f41a9a421575 100644 > --- a/drivers/mtd/nand/raw/qcom_nandc.c > +++ b/drivers/mtd/nand/raw/qcom_nandc.c > @@ -2,7 +2,6 @@ > /* > * Copyright (c) 2016, The Linux Foundation. All rights reserved. > */ > - > #include > #include > #include > @@ -3063,10 +3062,6 @@ static int qcom_nandc_probe(struct platform_device *pdev) > if (dma_mapping_error(dev, nandc->base_dma)) > return -ENXIO; > > - ret = qcom_nandc_alloc(nandc); > - if (ret) > - goto err_nandc_alloc; > - > ret = clk_prepare_enable(nandc->core_clk); > if (ret) > goto err_core_clk; > @@ -3075,6 +3070,10 @@ static int qcom_nandc_probe(struct platform_device *pdev) > if (ret) > goto err_aon_clk; > > + ret = qcom_nandc_alloc(nandc); > + if (ret) > + goto err_nandc_alloc; > + > ret = qcom_nandc_setup(nandc); > if (ret) > goto err_setup; > @@ -3086,15 +3085,14 @@ static int qcom_nandc_probe(struct platform_device *pdev) > return 0; > > err_setup: > + qcom_nandc_unalloc(nandc); > +err_nandc_alloc: > clk_disable_unprepare(nandc->aon_clk); > err_aon_clk: > clk_disable_unprepare(nandc->core_clk); > err_core_clk: > - qcom_nandc_unalloc(nandc); > -err_nandc_alloc: > dma_unmap_resource(dev, res->start, resource_size(res), > DMA_BIDIRECTIONAL, 0); > - > return ret; > } > > -- > 2.33.0 >