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

Yong Wu
2018-12-21T08:02:43Z

Hi Nicolas,

Thanks for the review of this patchset.

On Fri, 2018-12-21 at 11:35 +0800, Nicolas Boichat wrote:
> 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?

Actually I'd like the original way(Print the larb-id from the register
directly if larb-id is not remapped). But this solution is also ok for
me.

>
> Also, unsigned char/u8 array would be enough.

OK. "unsigned char" is enough.
Originally I think "int" or "long" may be better to access in ARM/ARM64.

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