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@chromium.org Signed-off-by: Yong Wu yong.wu@mediatek.com Tested-by: Frank Wunderlich frank-w@public-files.de # BPI-R2/MT7623 Acked-by: Joerg Roedel jroedel@suse.de Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@collabora.com --- drivers/iommu/mtk_iommu.c | 30 ++++++++++++++++++++++++++++++ drivers/iommu/mtk_iommu_v1.c | 29 ++++++++++++++++++++++++++++- 2 files changed, 58 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c index 5cff5bc556d4..77df61092be3 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 4089077256f4..4052aad75a81 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); }