Re: [PATCH v7 04/12] iommu/mediatek: Add device_link between the consumer and the larb devices

Dafna Hirschfeld
2021-08-05T13:22:14Z

On 30.07.21 04:52, 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@chromium.org>
> Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> Tested-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com> # on mt8173

Hi, unfortunately, I have to take back the Tested-by tag.
I am now testing the mtk-vcodec with latest kernel + patches sent from the mailing list:
https://gitlab.collabora.com/eballetbo/linux/-/commits/topic/chromeos/chromeos-5.14
which includes this patchset.

On chromeos I open a video conference with googl-meet which cause the mtk-vcodec vp8 encoder to run.
If I kill it with `killall -9 chrome` I get some page fault messages from the iommu:

[ 837.255952] mtk-iommu 10205000.iommu: fault type=0x5 iova=0xfcff0001 pa=0x0 larb=0 port=0 layer=1 read
[ 837.265696] mtk-iommu 10205000.iommu: fault type=0x5 iova=0xfcff0001 pa=0x0 larb=0 port=0 layer=1 read
[ 837.282367] mtk-iommu 10205000.iommu: fault type=0x5 iova=0xfcff0001 pa=0x0 larb=0 port=0 layer=1 read
[ 837.299028] mtk-iommu 10205000.iommu: fault type=0x5 iova=0xfcff0001 pa=0x0 larb=0 port=0 layer=1 read
[ 837.315683] mtk-iommu 10205000.iommu: fault type=0x5 iova=0xfcff0001 pa=0x0 larb=0 port=0 layer=1 read
[ 837.332345] mtk-iommu 10205000.iommu: fault type=0x5 iova=0xfcff0001 pa=0x0 larb=0 port=0 layer=1 read
[ 837.349004] mtk-iommu 10205000.iommu: fault type=0x5 iova=0xfcff0001 pa=0x0 larb=0 port=0 layer=1 read
[ 837.365665] mtk-iommu 10205000.iommu: fault type=0x5 iova=0xfcff0001 pa=0x0 larb=0 port=0 layer=1 read
[ 837.382329] mtk-iommu 10205000.iommu: fault type=0x5 iova=0xfcff0001 pa=0x0 larb=0 port=0 layer=1 read
[ 837.400002] mtk-iommu 10205000.iommu: fault type=0x5 iova=0xfcff0001 pa=0x0 larb=0 port=0 layer=1 read

In addition, running the encoder tests from the shell:

sudo --user=#1000 /usr/local/libexec/chrome-binary-tests/video_encode_accelerator_tests --gtest_filter=VideoEncoderTest.FlushAtEndOfStream_Multiple* --codec=vp8 /usr/local/share/tast/data/chromiumos/tast/local/bundles/cros/video/data/tulip2-320x180.yuv --disable_validator

At some point it fails with the error

[ 5472.161821] [MTK_V4L2][ERROR] mtk_vcodec_wait_for_done_ctx:32: [290] ctx->type=1, cmd=1, wait_event_interruptible_timeout time=1000ms out 0 0!
[ 5472.174678] [MTK_VCODEC][ERROR][290]: vp8_enc_encode_frame() irq_status=0 failed
[ 5472.182687] [MTK_V4L2][ERROR] mtk_venc_worker:1239: venc_if_encode failed=-5

If you have any idea of what might be the problem or how to debug?

Thanks,
Dafna

> ---
> 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));
> 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 c259433f1130..806d4200665b 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;
>
> /*
> * In the deferred case, free the existed fwspec if the dev already has,
> @@ -454,6 +456,14 @@ 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;
> }
>
> @@ -474,10 +484,18 @@ 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);
> }
>
>