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:
- 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.
- 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@chromium.org Signed-off-by: Yong Wu yong.wu@mediatek.com
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?
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); }