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 <tf...@chromium.org> Signed-off-by: Yong Wu <yong...@mediatek.com> --- 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]); + 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 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu