On Wed, 2021-07-14 at 10:26 +0200, Dafna Hirschfeld wrote: > > On 14.07.21 04:56, Yong Wu wrote: > > MediaTek IOMMU-SMI diagram is like below. 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] https://lore.kernel.org/linux-mediatek/1564213888.22908.4.camel@mhfsdcap03/ > > [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 | 22 ++++++++++++++++++++++ > > drivers/iommu/mtk_iommu_v1.c | 20 +++++++++++++++++++- > > 2 files changed, 41 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c > > index a02dde094788..ee742900cf4b 100644 > > --- a/drivers/iommu/mtk_iommu.c > > +++ b/drivers/iommu/mtk_iommu.c > > @@ -571,22 +571,44 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev) > > { > > struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); > > struct mtk_iommu_data *data; > > + struct device_link *link; > > + struct device *larbdev; > > + unsigned int larbid; > > > > if (!fwspec || fwspec->ops != &mtk_iommu_ops) > > return ERR_PTR(-ENODEV); /* Not a iommu client device */ > > > > data = dev_iommu_priv_get(dev); > > > > + /* > > + * Link the consumer device with the smi-larb device(supplier) > > + * The device in each a larb is a independent HW. thus only link > > + * one larb here. > > + */ > > + larbid = MTK_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)); > shoudn't ERR_PTR be returned in case of failure? In the previous design, this is not a fatal error. the consumer device could probe continuously even though it fail here..Returning here may let the issue be caught earlier, I will add this in next version. if (!link) { ... return ERR_PTR(EINVAL); } > > Thanks, > Dafna > > > return &data->iommu; > > } > > > > static void mtk_iommu_release_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; > > > > + data = dev_iommu_priv_get(dev); > > + larbid = MTK_M4U_TO_LARB(fwspec->ids[0]); > > + larbdev = data->larb_imu[larbid].dev; > > + device_link_remove(dev, larbdev); > > + > > iommu_fwspec_free(dev); > > } > > > > diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c > > index d9365a3d8dc9..d2a7c66b8239 100644 > > --- a/drivers/iommu/mtk_iommu_v1.c > > +++ b/drivers/iommu/mtk_iommu_v1.c > > @@ -424,7 +424,9 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev) > > struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); > > struct of_phandle_args iommu_spec; > > struct mtk_iommu_data *data; > > - int err, idx = 0; > > + int err, idx = 0, larbid; > > + struct device_link *link; > > + struct device *larbdev; > > > > while (!of_parse_phandle_with_args(dev->of_node, "iommus", > > "#iommu-cells", > > @@ -445,6 +447,14 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev) > > > > data = dev_iommu_priv_get(dev); > > > > + /* 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 &data->iommu; > > } > > > > @@ -465,10 +475,18 @@ static void mtk_iommu_probe_finalize(struct device *dev) > > static void mtk_iommu_release_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; > > > > + data = dev_iommu_priv_get(dev); > > + larbid = mt2701_m4u_to_larb(fwspec->ids[0]); > > + larbdev = data->larb_imu[larbid].dev; > > + device_link_remove(dev, larbdev); > > + > > iommu_fwspec_free(dev); > > } > > > >
