Re: [PATCH v5 13/20] iommu/mediatek: Add mt8183 IOMMU support

[Evan Green]

On Mon, Dec 31, 2018 at 7:59 PM Yong Wu <yong.wu@xxxxxxxxxxxx> wrote:
>
> The M4U IP blocks in mt8183 is MediaTek's generation2 M4U which use
> the ARM Short-descriptor like mt8173, and most of the HW registers
> are the same.
>
> Here list main differences between mt8183 and mt8173/mt2712:
> 1) mt8183 has only one M4U HW like mt8173 while mt2712 has two.
> 2) mt8183 don't have the "bclk" clock, it use the EMI clock instead.
> 3) mt8183 can support the dram over 4GB, but it doesn't call this "4GB
> mode".
> 4) mt8183 pgtable base register(0x0) extend bit[1:0] which represent
> the bit[33:32] in the physical address of the pgtable base, But the
> standard ttbr0[1] means the S bit which is enabled defaultly, Hence,
> we add a mask.
> 5) mt8183 HW has a GALS modules, SMI should enable "has_gals" support.
> 6) mt8183 need reset_axi like mt8173.
> 7) the larb-id in smi-common is remapped. M4U should add its larbid_remap.
>
> Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx>
> ---
>  drivers/iommu/mtk_iommu.c | 15 ++++++++++++---
>  drivers/iommu/mtk_iommu.h |  1 +
>  drivers/memory/mtk-smi.c  | 20 ++++++++++++++++++++
>  3 files changed, 33 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index 2913ddb..66e3615 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -36,6 +36,7 @@
>  #include "mtk_iommu.h"
>
>  #define REG_MMU_PT_BASE_ADDR                   0x000
> +#define MMU_PT_ADDR_MASK                       GENMASK(31, 7)
>
>  #define REG_MMU_INVALIDATE                     0x020
>  #define F_ALL_INVLD                            0x2
> @@ -342,7 +343,7 @@ static int mtk_iommu_attach_device(struct iommu_domain *domain,
>         /* Update the pgtable base address register of the M4U HW */
>         if (!data->m4u_dom) {
>                 data->m4u_dom = dom;
> -               writel(dom->cfg.arm_v7s_cfg.ttbr[0],
> +               writel(dom->cfg.arm_v7s_cfg.ttbr[0] & MMU_PT_ADDR_MASK,

So there aren't any other bits down below 7 that you need, like the
shareable bits?