Re: [PATCH v4 08/18] iommu/mediatek: Add larb-id remapped support

Nicolas Boichat
2018-12-21T03:35:51Z

On Sat, Dec 8, 2018 at 4:42 PM Yong Wu <yong.wu@mediatek.com> wrote:
>
> The larb-id may be remapped in the smi-common, this means the
> larb-id reported in the mtk_iommu_isr isn't the real larb-id,
>
> Take mt8183 as a example:
> M4U
> |
> ---------------------------------------------
> | SMI common |
> -0-----7-----5-----6-----1-----2------3-----4- <- Id remapped
> | | | | | | | |
> larb0 larb1 IPU0 IPU1 larb4 larb5 larb6 CCU
> disp vdec img cam venc img cam
> As above, larb0 connects with the id 0 in smi-common.
> larb1 connects with the id 7 in smi-common.
> ...
> If the larb-id reported in the isr is 7, actually it's larb1(vdec).
> In order to output the right larb-id in the isr, we add a larb-id
> remapping relationship in this patch.
>
> This also is a preparing patch for mt8183.
>
> Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> ---
> drivers/iommu/mtk_iommu.c | 3 +++
> drivers/iommu/mtk_iommu.h | 4 ++++
> 2 files changed, 7 insertions(+)
>
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index eda062a..8ab3b69 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -220,6 +220,9 @@ static irqreturn_t mtk_iommu_isr(int irq, void *dev_id)
> fault_larb = F_MMU0_INT_ID_LARB_ID(regval);
> fault_port = F_MMU0_INT_ID_PORT_ID(regval);
>
> + if (data->plat_data->larbid_remap_enable)
> + fault_larb = data->plat_data->larbid_remapped[fault_larb];
> +
> if (report_iommu_fault(&dom->domain, data->dev, fault_iova,
> write ? IOMMU_FAULT_WRITE : IOMMU_FAULT_READ)) {
> dev_err_ratelimited(
> diff --git a/drivers/iommu/mtk_iommu.h b/drivers/iommu/mtk_iommu.h
> index b8749ac..3877050 100644
> --- a/drivers/iommu/mtk_iommu.h
> +++ b/drivers/iommu/mtk_iommu.h
> @@ -47,6 +47,10 @@ struct mtk_iommu_plat_data {
>
> /* HW will use the EMI clock if there isn't the "bclk". */
> bool has_bclk;
> +
> + /* The larb-id may be remapped in the smi-common. */
> + bool larbid_remap_enable;
> + unsigned int larbid_remapped[MTK_LARB_NR_MAX];

Wouldn't it be a little simpler if you just had
larbid_remap[MTK_LARB_NR_MAX] (no larbid_remap_enable), and just set
it to {0, 1, 2, 3, 4, 5, 6, 7} in platforms that don't need
complicated remapping?

Also, unsigned char/u8 array would be enough.

> };
>
> struct mtk_iommu_domain;
> --
> 1.9.1
>