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? Do we need to iterate over all fwspecs->ids to figure out which larbs we need to add links to each of them? > + 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 >
