[PATCH] media: venus: core, venc, vdec: Fix probe dependency error

[PATCH] media: venus: core, venc, vdec: Fix probe dependency error

[Bryan O'Donoghue]

Commit aaaa93eda64b ("media] media: venus: venc: add video encoder files")
is the last in a series of three commits to add core.c vdec.c and venc.c
adding core, encoder and decoder.

The encoder and decoder check for core drvdata as set and return -EPROBE_DEFER
if it has not been set, however both the encoder and decoder rely on
core.v4l2_dev as valid.

core.v4l2_dev will not be valid until v4l2_device_register() has completed
in core.c's probe().

Normally this is never seen however, Dmitry reported the following
backtrace when compiling drivers and firmware directly into a kernel image.

[    5.259968] Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT)
[    5.269850] sd 0:0:0:3: [sdd] Optimal transfer size 524288 bytes
[    5.275505] Workqueue: events deferred_probe_work_func
[    5.275513] pstate: 60400005 (nZCv daif +PAN -UAO -TCO BTYPE=--)
[    5.441211] usb 2-1: new SuperSpeedPlus Gen 2 USB device number 2 using xhci-hcd
[    5.442486] pc : refcount_warn_saturate+0x140/0x148
[    5.493756] hub 2-1:1.0: USB hub found
[    5.496266] lr : refcount_warn_saturate+0x140/0x148
[    5.500982] hub 2-1:1.0: 4 ports detected
[    5.503440] sp : ffff80001067b730
[    5.503442] x29: ffff80001067b730
[    5.592660] usb 1-1: new high-speed USB device number 2 using xhci-hcd
[    5.598478] x28: ffff6c6bc1c379b8
[    5.598480] x27: ffffa5c673852960 x26: ffffa5c673852000
[    5.598484] x25: ffff6c6bc1c37800 x24: 0000000000000001
[    5.810652] x23: 0000000000000000 x22: ffffa5c673bc7118
[    5.813777] hub 1-1:1.0: USB hub found
[    5.816108] x21: ffffa5c674440000 x20: 0000000000000001
[    5.820846] hub 1-1:1.0: 4 ports detected
[    5.825415] x19: ffffa5c6744f4000 x18: ffffffffffffffff
[    5.825418] x17: 0000000000000000 x16: 0000000000000000
[    5.825421] x15: 00000a4810c193ba x14: 0000000000000000
[    5.825424] x13: 00000000000002b8 x12: 000000000000f20a
[    5.825427] x11: 000000000000f20a x10: 0000000000000038
[    5.845447] usb 2-1.1: new SuperSpeed Gen 1 USB device number 3 using xhci-hcd
[    5.845904]
[    5.845905] x9 : 0000000000000000 x8 : ffff6c6d36fae780
[    5.871208] x7 : ffff6c6d36faf240 x6 : 0000000000000000
[    5.876664] x5 : 0000000000000004 x4 : 0000000000000085
[    5.882121] x3 : 0000000000000119 x2 : ffffa5c6741ef478
[    5.887578] x1 : 3acbb3926faf5f00 x0 : 0000000000000000
[    5.893036] Call trace:
[    5.895551]  refcount_warn_saturate+0x140/0x148
[    5.900202]  __video_register_device+0x64c/0xd10
[    5.904944]  venc_probe+0xc4/0x148
[    5.908444]  platform_probe+0x68/0xe0
[    5.912210]  really_probe+0x118/0x3e0
[    5.915977]  driver_probe_device+0x5c/0xc0
[    5.920187]  __device_attach_driver+0x98/0xb8
[    5.924661]  bus_for_each_drv+0x68/0xd0
[    5.928604]  __device_attach+0xec/0x148
[    5.932547]  device_initial_probe+0x14/0x20
[    5.936845]  bus_probe_device+0x9c/0xa8
[    5.940788]  device_add+0x3e8/0x7c8
[    5.944376]  of_device_add+0x4c/0x60
[    5.948056]  of_platform_device_create_pdata+0xbc/0x140
[    5.953425]  of_platform_bus_create+0x17c/0x3c0
[    5.958078]  of_platform_populate+0x80/0x110
[    5.962463]  venus_probe+0x2ec/0x4d8
[    5.966143]  platform_probe+0x68/0xe0
[    5.969907]  really_probe+0x118/0x3e0
[    5.973674]  driver_probe_device+0x5c/0xc0
[    5.977882]  __device_attach_driver+0x98/0xb8
[    5.982356]  bus_for_each_drv+0x68/0xd0
[    5.986298]  __device_attach+0xec/0x148
[    5.990242]  device_initial_probe+0x14/0x20
[    5.994539]  bus_probe_device+0x9c/0xa8
[    5.998481]  deferred_probe_work_func+0x74/0xb0
[    6.003132]  process_one_work+0x1e8/0x360
[    6.007254]  worker_thread+0x208/0x478
[    6.011106]  kthread+0x150/0x158
[    6.014431]  ret_from_fork+0x10/0x30
[    6.018111] ---[ end trace f074246b1ecdb466 ]---

This patch fixes by

- Making core.v4l2_dev into core->v4l_dev
- Only setting core->v4l2_dev when v4l2_device_register() completes
- Deferring encoder/decoder probe until core->v4l2_dev is set

Reported-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Fixes: aaaa93eda64b ("media] media: venus: venc: add video encoder files")
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
---
 drivers/media/platform/qcom/venus/core.c | 14 +++++++++++---
 drivers/media/platform/qcom/venus/core.h |  2 +-
 drivers/media/platform/qcom/venus/vdec.c |  4 ++--
 drivers/media/platform/qcom/venus/venc.c |  4 ++--
 4 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/drivers/media/platform/qcom/venus/core.c b/drivers/media/platform/qcom/venus/core.c
index 07faed26c477..b4f1ae6ca146 100644
--- a/drivers/media/platform/qcom/venus/core.c
+++ b/drivers/media/platform/qcom/venus/core.c
@@ -231,6 +231,7 @@ static void venus_assign_register_offsets(struct venus_core *core)
 static int venus_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
+	struct v4l2_device *v4l2_dev;
 	struct venus_core *core;
 	struct resource *r;
 	int ret;
@@ -239,6 +240,10 @@ static int venus_probe(struct platform_device *pdev)
 	if (!core)
 		return -ENOMEM;
 
+	v4l2_dev = devm_kzalloc(dev, sizeof(*v4l2_dev), GFP_KERNEL);
+	if (!v4l2_dev)
+		return -ENOMEM;
+
 	core->dev = dev;
 	platform_set_drvdata(pdev, core);
 
@@ -331,10 +336,12 @@ static int venus_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_venus_shutdown;
 
-	ret = v4l2_device_register(dev, &core->v4l2_dev);
+	ret = v4l2_device_register(dev, v4l2_dev);
 	if (ret)
 		goto err_core_deinit;
 
+	core->v4l2_dev = v4l2_dev;
+
 	ret = pm_runtime_put_sync(dev);
 	if (ret) {
 		pm_runtime_get_noresume(dev);
@@ -346,7 +353,7 @@ static int venus_probe(struct platform_device *pdev)
 	return 0;
 
 err_dev_unregister:
-	v4l2_device_unregister(&core->v4l2_dev);
+	v4l2_device_unregister(core->v4l2_dev);
 err_core_deinit:
 	hfi_core_deinit(core, false);
 err_venus_shutdown:
@@ -391,7 +398,8 @@ static int venus_remove(struct platform_device *pdev)
 	icc_put(core->video_path);
 	icc_put(core->cpucfg_path);
 
-	v4l2_device_unregister(&core->v4l2_dev);
+	v4l2_device_unregister(core->v4l2_dev);
+
 	mutex_destroy(&core->pm_lock);
 	mutex_destroy(&core->lock);
 	venus_dbgfs_deinit(core);
diff --git a/drivers/media/platform/qcom/venus/core.h b/drivers/media/platform/qcom/venus/core.h
index 8328f7210d6c..baf4d01c18c9 100644
--- a/drivers/media/platform/qcom/venus/core.h
+++ b/drivers/media/platform/qcom/venus/core.h
@@ -150,7 +150,7 @@ struct venus_core {
 	struct reset_control *resets[VIDC_RESETS_NUM_MAX];
 	struct video_device *vdev_dec;
 	struct video_device *vdev_enc;
-	struct v4l2_device v4l2_dev;
+	struct v4l2_device *v4l2_dev;
 	const struct venus_resources *res;
 	struct device *dev;
 	struct device *dev_dec;
diff --git a/drivers/media/platform/qcom/venus/vdec.c b/drivers/media/platform/qcom/venus/vdec.c
index 9fbff40c4568..e5c81b59965b 100644
--- a/drivers/media/platform/qcom/venus/vdec.c
+++ b/drivers/media/platform/qcom/venus/vdec.c
@@ -1636,7 +1636,7 @@ static int vdec_probe(struct platform_device *pdev)
 		return -EPROBE_DEFER;
 
 	core = dev_get_drvdata(dev->parent);
-	if (!core)
+	if (!core || !core->v4l2_dev)
 		return -EPROBE_DEFER;
 
 	platform_set_drvdata(pdev, core);
@@ -1656,7 +1656,7 @@ static int vdec_probe(struct platform_device *pdev)
 	vdev->fops = &vdec_fops;
 	vdev->ioctl_ops = &vdec_ioctl_ops;
 	vdev->vfl_dir = VFL_DIR_M2M;
-	vdev->v4l2_dev = &core->v4l2_dev;
+	vdev->v4l2_dev = core->v4l2_dev;
 	vdev->device_caps = V4L2_CAP_VIDEO_M2M_MPLANE | V4L2_CAP_STREAMING;
 
 	ret = video_register_device(vdev, VFL_TYPE_VIDEO, -1);
diff --git a/drivers/media/platform/qcom/venus/venc.c b/drivers/media/platform/qcom/venus/venc.c
index 4b5ab0c790c9..ff2bf11bd89e 100644
--- a/drivers/media/platform/qcom/venus/venc.c
+++ b/drivers/media/platform/qcom/venus/venc.c
@@ -1242,7 +1242,7 @@ static int venc_probe(struct platform_device *pdev)
 		return -EPROBE_DEFER;
 
 	core = dev_get_drvdata(dev->parent);
-	if (!core)
+	if (!core || !core->v4l2_dev)
 		return -EPROBE_DEFER;
 
 	platform_set_drvdata(pdev, core);
@@ -1262,7 +1262,7 @@ static int venc_probe(struct platform_device *pdev)
 	vdev->fops = &venc_fops;
 	vdev->ioctl_ops = &venc_ioctl_ops;
 	vdev->vfl_dir = VFL_DIR_M2M;
-	vdev->v4l2_dev = &core->v4l2_dev;
+	vdev->v4l2_dev = core->v4l2_dev;
 	vdev->device_caps = V4L2_CAP_VIDEO_M2M_MPLANE | V4L2_CAP_STREAMING;
 
 	ret = video_register_device(vdev, VFL_TYPE_VIDEO, -1);
-- 
2.29.2

Re: [PATCH] media: venus: core, venc, vdec: Fix probe dependency error

[Stanimir Varbanov]

Hi Bryan,

Thanks for the fix!

On 2/4/21 2:56 PM, Bryan O'Donoghue wrote:
> Commit aaaa93eda64b ("media] media: venus: venc: add video encoder files")
> is the last in a series of three commits to add core.c vdec.c and venc.c
> adding core, encoder and decoder.
> 
> The encoder and decoder check for core drvdata as set and return -EPROBE_DEFER
> if it has not been set, however both the encoder and decoder rely on
> core.v4l2_dev as valid.
> 
> core.v4l2_dev will not be valid until v4l2_device_register() has completed
> in core.c's probe().
> 
> Normally this is never seen however, Dmitry reported the following
> backtrace when compiling drivers and firmware directly into a kernel image.
> 
> [    5.259968] Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT)
> [    5.269850] sd 0:0:0:3: [sdd] Optimal transfer size 524288 bytes
> [    5.275505] Workqueue: events deferred_probe_work_func
> [    5.275513] pstate: 60400005 (nZCv daif +PAN -UAO -TCO BTYPE=--)
> [    5.441211] usb 2-1: new SuperSpeedPlus Gen 2 USB device number 2 using xhci-hcd
> [    5.442486] pc : refcount_warn_saturate+0x140/0x148
> [    5.493756] hub 2-1:1.0: USB hub found
> [    5.496266] lr : refcount_warn_saturate+0x140/0x148
> [    5.500982] hub 2-1:1.0: 4 ports detected
> [    5.503440] sp : ffff80001067b730
> [    5.503442] x29: ffff80001067b730
> [    5.592660] usb 1-1: new high-speed USB device number 2 using xhci-hcd
> [    5.598478] x28: ffff6c6bc1c379b8
> [    5.598480] x27: ffffa5c673852960 x26: ffffa5c673852000
> [    5.598484] x25: ffff6c6bc1c37800 x24: 0000000000000001
> [    5.810652] x23: 0000000000000000 x22: ffffa5c673bc7118
> [    5.813777] hub 1-1:1.0: USB hub found
> [    5.816108] x21: ffffa5c674440000 x20: 0000000000000001
> [    5.820846] hub 1-1:1.0: 4 ports detected
> [    5.825415] x19: ffffa5c6744f4000 x18: ffffffffffffffff
> [    5.825418] x17: 0000000000000000 x16: 0000000000000000
> [    5.825421] x15: 00000a4810c193ba x14: 0000000000000000
> [    5.825424] x13: 00000000000002b8 x12: 000000000000f20a
> [    5.825427] x11: 000000000000f20a x10: 0000000000000038
> [    5.845447] usb 2-1.1: new SuperSpeed Gen 1 USB device number 3 using xhci-hcd
> [    5.845904]
> [    5.845905] x9 : 0000000000000000 x8 : ffff6c6d36fae780
> [    5.871208] x7 : ffff6c6d36faf240 x6 : 0000000000000000
> [    5.876664] x5 : 0000000000000004 x4 : 0000000000000085
> [    5.882121] x3 : 0000000000000119 x2 : ffffa5c6741ef478
> [    5.887578] x1 : 3acbb3926faf5f00 x0 : 0000000000000000
> [    5.893036] Call trace:
> [    5.895551]  refcount_warn_saturate+0x140/0x148
> [    5.900202]  __video_register_device+0x64c/0xd10
> [    5.904944]  venc_probe+0xc4/0x148
> [    5.908444]  platform_probe+0x68/0xe0
> [    5.912210]  really_probe+0x118/0x3e0
> [    5.915977]  driver_probe_device+0x5c/0xc0
> [    5.920187]  __device_attach_driver+0x98/0xb8
> [    5.924661]  bus_for_each_drv+0x68/0xd0
> [    5.928604]  __device_attach+0xec/0x148
> [    5.932547]  device_initial_probe+0x14/0x20
> [    5.936845]  bus_probe_device+0x9c/0xa8
> [    5.940788]  device_add+0x3e8/0x7c8
> [    5.944376]  of_device_add+0x4c/0x60
> [    5.948056]  of_platform_device_create_pdata+0xbc/0x140
> [    5.953425]  of_platform_bus_create+0x17c/0x3c0
> [    5.958078]  of_platform_populate+0x80/0x110
> [    5.962463]  venus_probe+0x2ec/0x4d8
> [    5.966143]  platform_probe+0x68/0xe0
> [    5.969907]  really_probe+0x118/0x3e0
> [    5.973674]  driver_probe_device+0x5c/0xc0
> [    5.977882]  __device_attach_driver+0x98/0xb8
> [    5.982356]  bus_for_each_drv+0x68/0xd0
> [    5.986298]  __device_attach+0xec/0x148
> [    5.990242]  device_initial_probe+0x14/0x20
> [    5.994539]  bus_probe_device+0x9c/0xa8
> [    5.998481]  deferred_probe_work_func+0x74/0xb0
> [    6.003132]  process_one_work+0x1e8/0x360
> [    6.007254]  worker_thread+0x208/0x478
> [    6.011106]  kthread+0x150/0x158
> [    6.014431]  ret_from_fork+0x10/0x30
> [    6.018111] ---[ end trace f074246b1ecdb466 ]---
> 
> This patch fixes by
> 
> - Making core.v4l2_dev into core->v4l_dev
> - Only setting core->v4l2_dev when v4l2_device_register() completes
> - Deferring encoder/decoder probe until core->v4l2_dev is set

Why not just move platform_set_drvdata(pdev, core) at the end of
venus_probe() after we registered v4l2_dev? I think this way we will
avoid this v4l2_dev gymnastics.

> 
> Reported-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> Fixes: aaaa93eda64b ("media] media: venus: venc: add video encoder files")
> Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
> ---
>  drivers/media/platform/qcom/venus/core.c | 14 +++++++++++---
>  drivers/media/platform/qcom/venus/core.h |  2 +-
>  drivers/media/platform/qcom/venus/vdec.c |  4 ++--
>  drivers/media/platform/qcom/venus/venc.c |  4 ++--
>  4 files changed, 16 insertions(+), 8 deletions(-)
> 


-- 
regards,
Stan

Re: [PATCH] media: venus: core, venc, vdec: Fix probe dependency error

[Bryan O'Donoghue]

On 05/02/2021 08:31, Stanimir Varbanov wrote:
> Why not just move platform_set_drvdata(pdev, core) at the end of
> venus_probe() after we registered v4l2_dev? I think this way we will
> avoid this v4l2_dev gymnastics.

Because pm_ops->core_functionname() relies on getdrvdata.

I changed that in a version of this fix which I didn't publish but also 
found that there were other dependencies in core::probe venc::probe and 
vdec::probe on drvdata.

I can publish a fix for drvdata and you can take your preference

Re: [PATCH] media: venus: core, venc, vdec: Fix probe dependency error

[Stanimir Varbanov]

On 2/5/21 1:24 PM, Bryan O'Donoghue wrote:
> On 05/02/2021 08:31, Stanimir Varbanov wrote:
>> Why not just move platform_set_drvdata(pdev, core) at the end of
>> venus_probe() after we registered v4l2_dev? I think this way we will
>> avoid this v4l2_dev gymnastics.
> 
> Because pm_ops->core_functionname() relies on getdrvdata.
> 
> I changed that in a version of this fix which I didn't publish but also
> found that there were other dependencies in core::probe venc::probe and
> vdec::probe on drvdata.
> 
> I can publish a fix for drvdata and you can take your preference

I'd prefer this solution. Do you see a problem if we change
core_get|put|power functional pointers from pm_ops to receive a
venus_core pointer instead of core->dev?


-- 
regards,
Stan

Re: [PATCH] media: venus: core, venc, vdec: Fix probe dependency error

[Stanimir Varbanov]

On 2/5/21 1:37 PM, Stanimir Varbanov wrote:
> 
> 
> On 2/5/21 1:24 PM, Bryan O'Donoghue wrote:
>> On 05/02/2021 08:31, Stanimir Varbanov wrote:
>>> Why not just move platform_set_drvdata(pdev, core) at the end of
>>> venus_probe() after we registered v4l2_dev? I think this way we will
>>> avoid this v4l2_dev gymnastics.
>>
>> Because pm_ops->core_functionname() relies on getdrvdata.
>>
>> I changed that in a version of this fix which I didn't publish but also
>> found that there were other dependencies in core::probe venc::probe and
>> vdec::probe on drvdata.
>>
>> I can publish a fix for drvdata and you can take your preference
> 
> I'd prefer this solution. Do you see a problem if we change
> core_get|put|power functional pointers from pm_ops to receive a
> venus_core pointer instead of core->dev?
> 
> 

Wait, venus_runtime_suspend|resume also relies on that
dev_get_drvdata(). Can we call v4l2_device_register() earlier in
venus_probe?

-- 
regards,
Stan

Re: [PATCH] media: venus: core, venc, vdec: Fix probe dependency error

[Bryan O'Donoghue]

On 05/02/2021 11:52, Stanimir Varbanov wrote:
> Wait, venus_runtime_suspend|resume also relies on that
> dev_get_drvdata(). Can we call v4l2_device_register() earlier in
> venus_probe?

I can give it a go