Hi Robin,
sorry for reply so late.
On Wed, 2019-02-27 at 19:30 +0000, Robin Murphy wrote:
> On 01/01/2019 04:51, Yong Wu wrote:
> > MediaTek IOMMU don't have its power-domain. all the consumer connect
> > with smi-larb, then connect with smi-common.
> >
> > M4U
> > |
> > smi-common
> > |
> > -------------
> > | | ...
> > | |
> > larb1 larb2
> > | |
> > vdec venc
> >
> > When the consumer works, it should enable the smi-larb's power which
> > also need enable the smi-common's power firstly.
> >
> > Thus, First of all, use the device link connect the consumer and the
> > smi-larbs. then add device link between the smi-larb and smi-common.
> >
> > This patch adds device_link between the consumer and the larbs.
> >
> > Suggested-by: Tomasz Figa <tfiga@xxxxxxxxxxxx>
> > Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx>
> > ---
> > drivers/iommu/mtk_iommu.c | 15 +++++++++++++--
> > drivers/iommu/mtk_iommu_v1.c | 14 ++++++++++++--
> > 2 files changed, 25 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index 202e41b..735ae8d 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -247,6 +247,7 @@ static void mtk_iommu_config(struct mtk_iommu_data *data,
> > struct mtk_smi_larb_iommu *larb_mmu;
> > unsigned int larbid, portid;
> > struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> > + struct device_link *link;
> > int i;
> >
> > for (i = 0; i < fwspec->num_ids; ++i) {
> > @@ -257,10 +258,20 @@ static void mtk_iommu_config(struct mtk_iommu_data *data,
> > dev_dbg(dev, "%s iommu port: %d\n",
> > enable ? "enable" : "disable", portid);
> >
> > - if (enable)
> > + if (enable) {
> > larb_mmu->mmu |= MTK_SMI_MMU_EN(portid);
> > - else
> > + /* Link the consumer with the larb device(supplier) */
> > + link = device_link_add(dev, larb_mmu->dev,
> > + DL_FLAG_PM_RUNTIME |
> > + DL_FLAG_AUTOREMOVE_CONSUMER);
>
> This looks technically wrong, since we get here from
> mtk_iommu_attach_device(), and in theory a device could get attached to
> any number of domains over its lifetime, so adding a link at this point
> when there's no corresponding cleanup on detach is definitely
> unbalanced. If you want this layer to manage the link on behalf of the
> consumer, it would probably be better to do it at the point of
> mtk_iommu_add_device(), and either track it for manual cleanup in
> mtk_iommu_remove_device() or rely on AUTOREMOVE_SUPPLIER.
Thanks. I will try to move the "device_link_add" in add_device in next
version.
>
> Robin.
>
> > + if (!link) {
> > + dev_err(dev, "Unable to link %s\n",
> > + dev_name(larb_mmu->dev));
> > + return;
> > + }
> > + } else {
> > larb_mmu->mmu &= ~MTK_SMI_MMU_EN(portid);
> > + }
> > }
> > }
> >
> > diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
> > index 9386aee..022bad9 100644
> > --- a/drivers/iommu/mtk_iommu_v1.c
> > +++ b/drivers/iommu/mtk_iommu_v1.c
> > @@ -201,6 +201,7 @@ static void mtk_iommu_config(struct mtk_iommu_data *data,
> > struct mtk_smi_larb_iommu *larb_mmu;
> > unsigned int larbid, portid;
> > struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> > + struct device_link *link;
> > int i;
> >
> > for (i = 0; i < fwspec->num_ids; ++i) {
> > @@ -211,10 +212,19 @@ static void mtk_iommu_config(struct mtk_iommu_data *data,
> > dev_dbg(dev, "%s iommu port: %d\n",
> > enable ? "enable" : "disable", portid);
> >
> > - if (enable)
> > + if (enable) {
> > larb_mmu->mmu |= MTK_SMI_MMU_EN(portid);
> > - else
> > + link = device_link_add(dev, larb_mmu->dev,
> > + DL_FLAG_PM_RUNTIME |
> > + DL_FLAG_AUTOREMOVE_CONSUMER);
> > + if (!link) {
> > + dev_err(dev, "Unable to link %s\n",
> > + dev_name(larb_mmu->dev));
> > + return;
> > + }
> > + } else {
> > larb_mmu->mmu &= ~MTK_SMI_MMU_EN(portid);
> > + }
> > }
> > }
> >
> >
