On Thu, 2020-03-05 at 13:14 +0800, Nicolas Boichat wrote: > On Tue, Sep 3, 2019 at 5:38 PM Yong Wu <yong.wu@xxxxxxxxxxxx> 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. > > > > When device_link_add, I add the flag DL_FLAG_STATELESS to avoid calling > > pm_runtime_xx to keep the original status of clocks. It can avoid two > > issues: > > 1) Display HW show fastlogo abnormally reported in [1]. At the beggining, > > all the clocks are enabled before entering kernel, but the clocks for > > display HW(always in larb0) will be gated after clk_enable and clk_disable > > called from device_link_add(->pm_runtime_resume) and rpm_idle. The clock > > operation happened before display driver probe. At that time, the display > > HW will be abnormal. > > > > 2) A deadlock issue reported in [2]. Use DL_FLAG_STATELESS to skip > > pm_runtime_xx to avoid the deadlock. > > > > Corresponding, DL_FLAG_AUTOREMOVE_CONSUMER can't be added, then > > device_link_removed should be added explicitly. > > > > [1] http://lists.infradead.org/pipermail/linux-mediatek/2019-July/ > > 021500.html > > [2] https://lore.kernel.org/patchwork/patch/1086569/ > > > > Suggested-by: Tomasz Figa <tfiga@xxxxxxxxxxxx> > > Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx> > > --- > > drivers/iommu/mtk_iommu.c | 17 +++++++++++++++++ > > drivers/iommu/mtk_iommu_v1.c | 18 +++++++++++++++++- > > 2 files changed, 34 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c > > index b138b94..2511b3c 100644 > > --- a/drivers/iommu/mtk_iommu.c > > +++ b/drivers/iommu/mtk_iommu.c > > @@ -450,6 +450,9 @@ static int mtk_iommu_add_device(struct device *dev) > > struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); > > struct mtk_iommu_data *data; > > struct iommu_group *group; > > + struct device_link *link; > > + struct device *larbdev; > > + unsigned int larbid; > > > > if (!fwspec || fwspec->ops != &mtk_iommu_ops) > > return -ENODEV; /* Not a iommu client device */ > > @@ -461,6 +464,14 @@ static int mtk_iommu_add_device(struct device *dev) > > if (IS_ERR(group)) > > return PTR_ERR(group); > > > > + /* Link the consumer device with the smi-larb device(supplier) */ > > + larbid = MTK_M4U_TO_LARB(fwspec->ids[0]); > > I'll mirror the comment I made on gerrit > (https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/1361013): > Maybe I'm missing something here, but for example, on MT8173, > vcodec_enc: vcodec@18002000 needs to use both larb3 and larb5, isn't > the code below just adding a link for larb3? Yes. It only add larb3 here. > > Do we need to iterate over all fwspecs->ids to figure out which larbs > we need to add links to each of them? We have checked this venc issue. Currently I have requested our venc guy to seperate larb3-venc and larb5-venc in the driver[1] since they are independent HW actually. I will put it into this series when I send next version. If there is some reasonable driver which have two larbs in it, then the iterating is really necessary, But I don't see it right now. Only using fwspec->ids[0] is enough for now. [1] https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/1958322 > > > + larbdev = data->larb_imu[larbid].dev; > > + link = device_link_add(dev, larbdev, > > + DL_FLAG_PM_RUNTIME | DL_FLAG_STATELESS); > > + if (!link) > > + dev_err(dev, "Unable to link %s\n", dev_name(larbdev)); > > + > > iommu_group_put(group); > > return 0; > > } > > @@ -469,6 +480,8 @@ static void mtk_iommu_remove_device(struct device *dev) > > { > > struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); > > struct mtk_iommu_data *data; > > + struct device *larbdev; > > + unsigned int larbid; > > > > if (!fwspec || fwspec->ops != &mtk_iommu_ops) > > return; > > @@ -476,6 +489,10 @@ static void mtk_iommu_remove_device(struct device *dev) > > data = fwspec->iommu_priv; > > iommu_device_unlink(&data->iommu, dev); > > > > + larbid = MTK_M4U_TO_LARB(fwspec->ids[0]); > > + larbdev = data->larb_imu[larbid].dev; > > + device_link_remove(dev, larbdev); > > + > > iommu_group_remove_device(dev); > > iommu_fwspec_free(dev); > > } > > diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c > > index 2034d72..a7f22a2 100644 > > --- a/drivers/iommu/mtk_iommu_v1.c > > +++ b/drivers/iommu/mtk_iommu_v1.c > > @@ -423,7 +423,9 @@ static int mtk_iommu_add_device(struct device *dev) > > struct of_phandle_iterator it; > > struct mtk_iommu_data *data; > > struct iommu_group *group; > > - int err; > > + struct device_link *link; > > + struct device *larbdev; > > + int err, larbid; > > > > of_for_each_phandle(&it, err, dev->of_node, "iommus", > > "#iommu-cells", 0) { > > @@ -466,6 +468,14 @@ static int mtk_iommu_add_device(struct device *dev) > > return err; > > } > > > > + /* Link the consumer device with the smi-larb device(supplier) */ > > + larbid = mt2701_m4u_to_larb(fwspec->ids[0]); > > + larbdev = data->larb_imu[larbid].dev; > > + link = device_link_add(dev, larbdev, > > + DL_FLAG_PM_RUNTIME | DL_FLAG_STATELESS); > > + if (!link) > > + dev_err(dev, "Unable to link %s\n", dev_name(larbdev)); > > + > > return iommu_device_link(&data->iommu, dev); > > } > > > > @@ -473,6 +483,8 @@ static void mtk_iommu_remove_device(struct device *dev) > > { > > struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); > > struct mtk_iommu_data *data; > > + struct device *larbdev; > > + unsigned int larbid; > > > > if (!fwspec || fwspec->ops != &mtk_iommu_ops) > > return; > > @@ -480,6 +492,10 @@ static void mtk_iommu_remove_device(struct device *dev) > > data = fwspec->iommu_priv; > > iommu_device_unlink(&data->iommu, dev); > > > > + larbid = mt2701_m4u_to_larb(fwspec->ids[0]); > > + larbdev = data->larb_imu[larbid].dev; > > + device_link_remove(dev, larbdev); > > + > > iommu_group_remove_device(dev); > > iommu_fwspec_free(dev); > > } > > -- > > 1.9.1 > >