On Fri, 2015-12-18 at 17:44 +0000, Robin Murphy wrote: > On 18/12/15 08:09, Yong Wu wrote: > > This patch adds support for mediatek m4u (MultiMedia Memory Management > > Unit). > > > > Signed-off-by: Yong Wu <yong...@mediatek.com> > > --- > > drivers/iommu/Kconfig | 14 + > > drivers/iommu/Makefile | 1 + > > drivers/iommu/mtk_iommu.c | 734 > > ++++++++++++++++++++++++++++++++++++++++++++++ > > 3 files changed, 749 insertions(+) > > create mode 100644 drivers/iommu/mtk_iommu.c > > > > > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c > > new file mode 100644 > > index 0000000..d000d31 > > --- /dev/null > > +++ b/drivers/iommu/mtk_iommu.c > > [...] > > > +#define REG_MMU_CTRL_REG 0x110 > > +#define F_MMU_PREFETCH_RT_REPLACE_MOD BIT(4) > > +#define F_MMU_TF_PROTECT_SEL(prot) (((prot) & 0x3) << 5) > > +#define F_COHERENCE_EN BIT(8) > > [...] > > > +static int mtk_iommu_hw_init(const struct mtk_iommu_data *data) > > +{ > > + u32 regval; > > + int ret; > > + > > + ret = clk_prepare_enable(data->bclk); > > + if (ret) { > > + dev_err(data->dev, "Failed to enable iommu bclk(%d)\n", ret); > > + return ret; > > + } > > + > > + regval = F_MMU_PREFETCH_RT_REPLACE_MOD | > > + F_MMU_TF_PROTECT_SEL(2) | > > + F_COHERENCE_EN; > > I meant to ask this last time - does setting F_COHERENCE_EN here imply > that the M4U is capable of cache-coherent page table walks, or something > else? If it's the former, and assuming the MT8173 is actually wired up > to support that, then you should add a dma-coherent property to its DT > node in patch 5 (which will also save you all the cache flushes on page > table updates).
No. F_COHERENCE_EN is not for m4u's cache-coherent page table walking. More about it: There are two iommu cells in the HW. one is perisys-iommu, the other is mm-iommu. The perisys-iommu currently is not contained in this upstream version. it will support this F_COHERENCE_EN bit which will enable coherence access for the master port if the sharable(S) bit is set in the pagetable descriptor. And in the mm-iommu, the iommu HW will work regardless of this bit. So I will delete this bit for readable as this is m4u(mm-iommu) in next time. > > > + writel_relaxed(regval, data->base + REG_MMU_CTRL_REG); > > + > > + regval = F_L2_MULIT_HIT_EN | > > + F_TABLE_WALK_FAULT_INT_EN | > > + F_PREETCH_FIFO_OVERFLOW_INT_EN | > > + F_MISS_FIFO_OVERFLOW_INT_EN | > > + F_PREFETCH_FIFO_ERR_INT_EN | > > + F_MISS_FIFO_ERR_INT_EN; > > + writel_relaxed(regval, data->base + REG_MMU_INT_CONTROL0); > > + > > + regval = F_INT_TRANSLATION_FAULT | > > + F_INT_MAIN_MULTI_HIT_FAULT | > > + F_INT_INVALID_PA_FAULT | > > + F_INT_ENTRY_REPLACEMENT_FAULT | > > + F_INT_TLB_MISS_FAULT | > > + F_INT_MISS_TRANSATION_FIFO_FAULT | > > + F_INT_PRETETCH_TRANSATION_FIFO_FAULT; > > + writel_relaxed(regval, data->base + REG_MMU_INT_MAIN_CONTROL); > > + > > + regval = F_MMU_IVRP_PA_SET(data->protect_base); > > + writel_relaxed(regval, data->base + REG_MMU_IVRP_PADDR); > > + > > + writel_relaxed(0, data->base + REG_MMU_DCM_DIS); > > + writel_relaxed(0, data->base + REG_MMU_STANDARD_AXI_MODE); > > + > > + if (devm_request_irq(data->dev, data->irq, mtk_iommu_isr, 0, > > + dev_name(data->dev), (void *)data)) { > > + writel_relaxed(0, data->base + REG_MMU_PT_BASE_ADDR); > > + clk_disable_unprepare(data->bclk); > > + dev_err(data->dev, "Failed @ IRQ-%d Request\n", data->irq); > > + return -ENODEV; > > + } > > + > > + return 0; > > +} > > Otherwise, I've not had the chance to go through this thoroughly but at > a glance it seems in pretty good shape now - nothing immediately jumps > out as looking wrong or worth making a fuss over. > > Thanks, > Robin. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/