On Tue, 2019-06-18 at 15:19 +0900, Tomasz Figa wrote: > On Mon, Jun 10, 2019 at 9:21 PM Yong Wu <yong.wu@xxxxxxxxxxxx> wrote: > > > > Normally the M4U HW connect EMI with smi. the diagram is like below: > > EMI > > | > > M4U > > | > > smi-common > > | > > ----------------- > > | | | | ... > > larb0 larb1 larb2 larb3 > > > > Actually there are 2 mmu cells in the M4U HW, like this diagram: > > > > EMI > > --------- > > | | > > mmu0 mmu1 <- M4U > > | | > > --------- > > | > > smi-common > > | > > ----------------- > > | | | | ... > > larb0 larb1 larb2 larb3 > > > > This patch add support for mmu1. In order to get better performance, > > we could adjust some larbs go to mmu1 while the others still go to > > mmu0. This is controlled by a SMI COMMON register SMI_BUS_SEL(0x220). > > > > mt2712, mt8173 and mt8183 M4U HW all have 2 mmu cells. the default > > value of that register is 0 which means all the larbs go to mmu0 > > defaultly. > > > > This is a preparing patch for adjusting SMI_BUS_SEL for mt8183. > > > > Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx> > > Reviewed-by: Evan Green <evgreen@xxxxxxxxxxxx> > > --- > > drivers/iommu/mtk_iommu.c | 46 +++++++++++++++++++++++++++++----------------- > > 1 file changed, 29 insertions(+), 17 deletions(-) > > > > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c > > index 3a14301..ec4ce74 100644 > > --- a/drivers/iommu/mtk_iommu.c > > +++ b/drivers/iommu/mtk_iommu.c > > @@ -72,26 +72,32 @@ > > #define F_INT_CLR_BIT BIT(12) > > > > #define REG_MMU_INT_MAIN_CONTROL 0x124 > > -#define F_INT_TRANSLATION_FAULT BIT(0) > > -#define F_INT_MAIN_MULTI_HIT_FAULT BIT(1) > > -#define F_INT_INVALID_PA_FAULT BIT(2) > > -#define F_INT_ENTRY_REPLACEMENT_FAULT BIT(3) > > -#define F_INT_TLB_MISS_FAULT BIT(4) > > -#define F_INT_MISS_TRANSACTION_FIFO_FAULT BIT(5) > > -#define F_INT_PRETETCH_TRANSATION_FIFO_FAULT BIT(6) > > + /* mmu0 | mmu1 */ > > +#define F_INT_TRANSLATION_FAULT (BIT(0) | BIT(7)) > > +#define F_INT_MAIN_MULTI_HIT_FAULT (BIT(1) | BIT(8)) > > +#define F_INT_INVALID_PA_FAULT (BIT(2) | BIT(9)) > > +#define F_INT_ENTRY_REPLACEMENT_FAULT (BIT(3) | BIT(10)) > > +#define F_INT_TLB_MISS_FAULT (BIT(4) | BIT(11)) > > +#define F_INT_MISS_TRANSACTION_FIFO_FAULT (BIT(5) | BIT(12)) > > +#define F_INT_PRETETCH_TRANSATION_FIFO_FAULT (BIT(6) | BIT(13)) > > If there are two IOMMUs, shouldn't we have two driver instances handle > them, instead of making the driver combine them two internally? Actually it means only one IOMMU(M4U) HW here. Each a M4U HW has two small iommu cells which have independent MTLB. As the diagram above, M4U contain mmu0 and mmu1. MT8173 and MT8183 have only one M4U HW while MT2712 have 2 M4U HWs(two driver instances). > > And, what is even more important from security point of view actually, > have two separate page tables (aka IOMMU groups) for them? Each a IOMMU(M4U) have its own pagetable, thus, mt8183 have only one pagetable while mt2712 have two. > > Best regards, > Tomasz > > _______________________________________________ > Linux-mediatek mailing list > Linux-mediatek@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-mediatek
