From: Stephen Warren <swarren@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx> > 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-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
