This is a note to let you know that I've just added the patch titled media: iommu/mediatek: Add device_link between the consumer and the larb devices to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: media-iommu-mediatek-add-device_link-between-the-con.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 4b0b9e4f06d923530d8cfe1bbf0eae721cd8c71e Author: Yong Wu <yong.wu@xxxxxxxxxxxx> Date: Mon Jan 17 08:05:02 2022 +0100 media: iommu/mediatek: Add device_link between the consumer and the larb devices [ Upstream commit 635319a4a7444ca97124d781cd96deb277ff4d40 ] 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. Meanwhile, Currently we don't have a device connect with 2 larbs at the same time. Disallow this case, print the error log. [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> Tested-by: Frank Wunderlich <frank-w@xxxxxxxxxxxxxxx> # BPI-R2/MT7623 Acked-by: Joerg Roedel <jroedel@xxxxxxx> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx> Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c index 77ae20ff9b35..5971a1168666 100644 --- a/drivers/iommu/mtk_iommu.c +++ b/drivers/iommu/mtk_iommu.c @@ -562,22 +562,52 @@ 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, larbidx, i; 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 that connects with each a larb is a independent HW. + * All the ports in each a device should be in the same larbs. + */ + larbid = MTK_M4U_TO_LARB(fwspec->ids[0]); + for (i = 1; i < fwspec->num_ids; i++) { + larbidx = MTK_M4U_TO_LARB(fwspec->ids[i]); + if (larbid != larbidx) { + dev_err(dev, "Can only use one larb. Fail@larb%d-%d.\n", + larbid, larbidx); + return ERR_PTR(-EINVAL); + } + } + 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; } 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 68bf02f87cfd..bc7ee90b9373 100644 --- a/drivers/iommu/mtk_iommu_v1.c +++ b/drivers/iommu/mtk_iommu_v1.c @@ -423,7 +423,9 @@ 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, larbidx; + struct device_link *link; + struct device *larbdev; /* * In the deferred case, free the existed fwspec. @@ -453,6 +455,23 @@ 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]); + for (idx = 1; idx < fwspec->num_ids; idx++) { + larbidx = mt2701_m4u_to_larb(fwspec->ids[idx]); + if (larbid != larbidx) { + dev_err(dev, "Can only use one larb. Fail@larb%d-%d.\n", + larbid, larbidx); + return ERR_PTR(-EINVAL); + } + } + + 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; } @@ -473,10 +492,18 @@ 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); }