On Mon, 2015-12-14 at 19:18 +0100, Matthias Brugger wrote: > On Tuesday 08 Dec 2015 17:49:11 Yong Wu wrote: > > This patch add SMI(Smart Multimedia Interface) driver. This driver > > is responsible to enable/disable iommu and control the power domain > > and clocks of each local arbiter. > > > > Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx> > > --- > > Currently SMI offer mtk_smi_larb_get/put to enable the power-domain > > ,clocks and initialize the iommu configuration register for each a local > > arbiter, The reason is: > > a) If a device would like to disable iommu, it also need call > > mtk_smi_larb_get/put to enable its power and clocks. > > b) The iommu core don't support attach/detach a device within a > > iommu-group. So we cann't use iommu_attach_device(iommu_detach_device) > > instead > > of mtk_smi_larb_get/put. > > [..] > > +static int > > +mtk_smi_enable(struct device *dev, struct clk *apb, struct clk *smi) > > +{ > > + int ret; > > + > > + ret = pm_runtime_get_sync(dev); > > + if (ret < 0) > > + return ret; > > + > > + ret = clk_prepare_enable(apb); > > + if (ret) > > + goto err_put_pm; > > + > > + ret = clk_prepare_enable(smi); > > + if (ret) > > + goto err_disable_apb; > > + > > + return 0; > > + > > +err_disable_apb: > > + clk_disable_unprepare(apb); > > +err_put_pm: > > + pm_runtime_put_sync(dev); > > + return ret; > > +} > > + > > +static void > > +mtk_smi_disable(struct device *dev, struct clk *apb, struct clk *smi) > > +{ > > + clk_disable_unprepare(smi); > > + clk_disable_unprepare(apb); > > + pm_runtime_put_sync(dev); > > +} > > + > > +static int mtk_smi_common_enable(struct mtk_smi_common *common) > > +{ > > + return mtk_smi_enable(common->dev, common->clk_apb, common->clk_smi); > > +} > > + > > +static void mtk_smi_common_disable(struct mtk_smi_common *common) > > +{ > > + mtk_smi_disable(common->dev, common->clk_apb, common->clk_smi); > > +} > > + > > +static int mtk_smi_larb_enable(struct mtk_smi_larb *larb) > > +{ > > + return mtk_smi_enable(larb->dev, larb->clk_apb, larb->clk_smi); > > +} > > + > > +static void mtk_smi_larb_disable(struct mtk_smi_larb *larb) > > +{ > > + mtk_smi_disable(larb->dev, larb->clk_apb, larb->clk_smi); > > +} > > + > > This is somehow over-engineered. Just use mtk_smi_enable and mtk_smi_disable > instead of adding an extra indirection. I added this only for readable...then the code in mtk_smi_larb_get below may looks simple and readable. If I use mtk_smi_enable/disable directly, the code will be like our v5[1], is it OK? Maybe I don't need these help function here, and only add more comment based on v5. [1] http://lists.linuxfoundation.org/pipermail/iommu/2015-October/014590.html > > > +int mtk_smi_larb_get(struct device *larbdev) > > +{ > > + struct mtk_smi_larb *larb = dev_get_drvdata(larbdev); > > + struct mtk_smi_common *common = dev_get_drvdata(larb->smi_common_dev); > > + int ret; > > + > > + ret = mtk_smi_common_enable(common); > > + if (ret) > > + return ret; > > + > > + ret = mtk_smi_larb_enable(larb); > > + if (ret) > > + goto err_put_smi; > > + > > + /* Configure the iommu info */ > > + writel_relaxed(larb->mmu, larb->base + SMI_LARB_MMU_EN); > > + > > + return 0; > > + > > +err_put_smi: > > + mtk_smi_common_disable(common); > > + return ret; > > +} > > + > > +void mtk_smi_larb_put(struct device *larbdev) > > +{ > > + struct mtk_smi_larb *larb = dev_get_drvdata(larbdev); > > + struct mtk_smi_common *common = dev_get_drvdata(larb->smi_common_dev); > > + > > + writel_relaxed(0, larb->base + SMI_LARB_MMU_EN); > > + mtk_smi_larb_disable(larb); > > + mtk_smi_common_disable(common); > > +} > > + > > Looks strange that you just disable all MMUs while you only enable some of > them at runtime. Unfortunately the datasheet I have lacks the SMI part, so I > can just guess how the HW is working. > From the DTS it looks like as if a larb can be used by two different > components (e.g. larb0 from ovl0 and rdma0). Wouldn't that produce a conflict? Thanks. It's really a problem. There are OVL0 and MDP in larb0, Both will call mtk_smi_larb_get/put, we cann't disable all the MMUs in whole the larb0 here. This register should be reset to zero while the larb power domain turning off(rely on the power-domain ref count). I will delete this(keep this in our V5.) > > Regards, > Matthias -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html