Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932087Ab2ECRs3 (ORCPT ); Thu, 3 May 2012 13:48:29 -0400 Received: from avon.wwwdotorg.org ([70.85.31.133]:32877 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752239Ab2ECRs2 (ORCPT ); Thu, 3 May 2012 13:48:28 -0400 Message-ID: <4FA2C4E9.2080509@wwwdotorg.org> Date: Thu, 03 May 2012 11:48:25 -0600 From: Stephen Warren User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.28) Gecko/20120313 Thunderbird/3.1.20 MIME-Version: 1.0 To: Hiroshi DOYU CC: linux-tegra@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Joerg Roedel , Thierry Reding , linux-kernel@vger.kernel.org Subject: Re: [PATCHv3 3/4] iommu/tegra: smmu: Refrain from accessing to AHB References: <1336061147-10245-1-git-send-email-hdoyu@nvidia.com> <1336061147-10245-3-git-send-email-hdoyu@nvidia.com> In-Reply-To: <1336061147-10245-3-git-send-email-hdoyu@nvidia.com> X-Enigmail-Version: 1.1.2 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1445 Lines: 37 On 05/03/2012 10:05 AM, Hiroshi DOYU wrote: > Use "tegra_ahb_enable_smmu()" to inform AHB that SMMU is > ready, instead of directly aceessing AHB registers. You need to make the Kconfig option for the SMMU either depend on or select the TEGRA_AHB option. If you don't, then if someone disables the AHB driver, the SMMU driver may still build, yet fail to link since the AHB API it calls doesn't exist. > diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c > @@ -398,10 +388,8 @@ static void smmu_setup_regs(struct smmu_device *smmu) > > smmu_flush_regs(smmu, 1); > > - val = ahb_read(smmu, AHB_XBAR_CTRL); > - val |= AHB_XBAR_CTRL_SMMU_INIT_DONE_DONE << > - AHB_XBAR_CTRL_SMMU_INIT_DONE_SHIFT; > - ahb_write(smmu, val, AHB_XBAR_CTRL); > + err = tegra_ahb_enable_smmu(smmu->ahb); > + return err; You can just "return tegra_ahb_..." here. > @@ -911,14 +899,16 @@ static int tegra_smmu_probe(struct platform_device *pdev) > + smmu->ahb = of_parse_phandle(pdev->dev.of_node, "ahb", 0); Hmm, "ahb" should probably be "nvidia,ahb". I see that neither this patch nor the next patch include binding documentation that describe this property. Can you please add documentation. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/