Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757950Ab2ECRyq (ORCPT ); Thu, 3 May 2012 13:54:46 -0400 Received: from hqemgate03.nvidia.com ([216.228.121.140]:18531 "EHLO hqemgate03.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753464Ab2ECRyp convert rfc822-to-8bit (ORCPT ); Thu, 3 May 2012 13:54:45 -0400 X-PGP-Universal: processed; by hqnvupgp08.nvidia.com on Thu, 03 May 2012 10:54:36 -0700 From: Hiroshi Doyu To: "swarren@wwwdotorg.org" CC: "linux-tegra@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "joerg.roedel@amd.com" , "thierry.reding@avionic-design.de" , "linux-kernel@vger.kernel.org" Date: Thu, 3 May 2012 19:54:31 +0200 Subject: Re: [PATCHv3 3/4] iommu/tegra: smmu: Refrain from accessing to AHB Thread-Topic: [PATCHv3 3/4] iommu/tegra: smmu: Refrain from accessing to AHB Thread-Index: Ac0pVcv3zzCrkQ8BQSS8lwe3UtFs0Q== Message-ID: <20120503.205431.1876975023371235981.hdoyu@nvidia.com> References: <1336061147-10245-1-git-send-email-hdoyu@nvidia.com><1336061147-10245-3-git-send-email-hdoyu@nvidia.com><4FA2C4E9.2080509@wwwdotorg.org> In-Reply-To: <4FA2C4E9.2080509@wwwdotorg.org> Accept-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-nvconfidentiality: public acceptlanguage: en-US Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1927 Lines: 49 From: Stephen Warren Subject: Re: [PATCHv3 3/4] iommu/tegra: smmu: Refrain from accessing to AHB Date: Thu, 3 May 2012 19:48:25 +0200 Message-ID: <4FA2C4E9.2080509@wwwdotorg.org> > 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. There will be the tegra Memory Controller(MC) patches following, which will change the way DT is passed, where SMMU/dt is passed from MC. Can we wait for the following MC patches, not haveing doc for this patch? -- 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/