[PATCH] drm/msm/adreno: fix gpu probe if no interconnect-names

[PATCH] drm/msm/adreno: fix gpu probe if no interconnect-names

[Rob Clark]

From: Rob Clark <robdclark@chromium.org>

If there is no interconnect-names, but there is an interconnects
property, then of_icc_get(dev, "gfx-mem"); would return an error
rather than NULL.

Also, if there is no interconnect-names property, there will never
be a ocmem path.  But of_icc_get(dev, "ocmem") would return -EINVAL
instead of -ENODATA.  Just don't bother trying in this case.

Fixes: 8e29fb37b301 ("drm/msm: handle for EPROBE_DEFER for of_icc_get")
Signed-off-by: Rob Clark <robdclark@chromium.org>
---
 drivers/gpu/drm/msm/adreno/adreno_gpu.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
index 0527e85184e1..c4ac998b90c8 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
@@ -979,6 +979,7 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
 	struct adreno_platform_config *config = dev->platform_data;
 	struct msm_gpu_config adreno_gpu_config  = { 0 };
 	struct msm_gpu *gpu = &adreno_gpu->base;
+	bool has_interconnect_names = true;
 	int ret;
 
 	adreno_gpu->funcs = funcs;
@@ -1005,12 +1006,13 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
 
 	/* Check for an interconnect path for the bus */
 	gpu->icc_path = of_icc_get(dev, "gfx-mem");
-	if (!gpu->icc_path) {
+	if (IS_ERR_OR_NULL(gpu->icc_path)) {
 		/*
 		 * Keep compatbility with device trees that don't have an
 		 * interconnect-names property.
 		 */
 		gpu->icc_path = of_icc_get(dev, NULL);
+		has_interconnect_names = false;
 	}
 	if (IS_ERR(gpu->icc_path)) {
 		ret = PTR_ERR(gpu->icc_path);
@@ -1018,7 +1020,9 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
 		return ret;
 	}
 
-	gpu->ocmem_icc_path = of_icc_get(dev, "ocmem");
+	if (has_interconnect_names)
+		gpu->ocmem_icc_path = of_icc_get(dev, "ocmem");
+
 	if (IS_ERR(gpu->ocmem_icc_path)) {
 		ret = PTR_ERR(gpu->ocmem_icc_path);
 		gpu->ocmem_icc_path = NULL;
-- 
2.26.2

Re: [PATCH] drm/msm/adreno: fix gpu probe if no interconnect-names

[Jonathan Marek]

On 7/15/20 2:29 PM, Rob Clark wrote:
> From: Rob Clark <robdclark@chromium.org>
> 
> If there is no interconnect-names, but there is an interconnects
> property, then of_icc_get(dev, "gfx-mem"); would return an error
> rather than NULL.
> 
> Also, if there is no interconnect-names property, there will never
> be a ocmem path.  But of_icc_get(dev, "ocmem") would return -EINVAL
> instead of -ENODATA.  Just don't bother trying in this case.
> 
> Fixes: 8e29fb37b301 ("drm/msm: handle for EPROBE_DEFER for of_icc_get")
> Signed-off-by: Rob Clark <robdclark@chromium.org>
> ---
>   drivers/gpu/drm/msm/adreno/adreno_gpu.c | 8 ++++++--
>   1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> index 0527e85184e1..c4ac998b90c8 100644
> --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> @@ -979,6 +979,7 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
>   	struct adreno_platform_config *config = dev->platform_data;
>   	struct msm_gpu_config adreno_gpu_config  = { 0 };
>   	struct msm_gpu *gpu = &adreno_gpu->base;
> +	bool has_interconnect_names = true;
>   	int ret;
>   
>   	adreno_gpu->funcs = funcs;
> @@ -1005,12 +1006,13 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
>   
>   	/* Check for an interconnect path for the bus */
>   	gpu->icc_path = of_icc_get(dev, "gfx-mem");
> -	if (!gpu->icc_path) {
> +	if (IS_ERR_OR_NULL(gpu->icc_path)) {
>   		/*
>   		 * Keep compatbility with device trees that don't have an
>   		 * interconnect-names property.
>   		 */
>   		gpu->icc_path = of_icc_get(dev, NULL);

This is misleading because if it gets a EPROBE_DEFER error (or any other 
error), it will hit this path. Maybe there's a specific error you can 
check for instead to identify the "no-interconnect-names" case?

Also don't think its a good idea to be calling of_icc_get(dev, NULL) 
again when there's a EPROBE_DEFER, the interconnect driver could come up 
between the two calls

> +		has_interconnect_names = false;
>   	}
>   	if (IS_ERR(gpu->icc_path)) {
>   		ret = PTR_ERR(gpu->icc_path);
> @@ -1018,7 +1020,9 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
>   		return ret;
>   	}
>   
> -	gpu->ocmem_icc_path = of_icc_get(dev, "ocmem");
> +	if (has_interconnect_names)
> +		gpu->ocmem_icc_path = of_icc_get(dev, "ocmem");
> +
>   	if (IS_ERR(gpu->ocmem_icc_path)) {
>   		ret = PTR_ERR(gpu->ocmem_icc_path);
>   		gpu->ocmem_icc_path = NULL;
> 

Re: [PATCH] drm/msm/adreno: fix gpu probe if no interconnect-names

[Rob Clark]

On Wed, Jul 15, 2020 at 11:37 AM Jonathan Marek <jonathan@marek.ca> wrote:
>
> On 7/15/20 2:29 PM, Rob Clark wrote:
> > From: Rob Clark <robdclark@chromium.org>
> >
> > If there is no interconnect-names, but there is an interconnects
> > property, then of_icc_get(dev, "gfx-mem"); would return an error
> > rather than NULL.
> >
> > Also, if there is no interconnect-names property, there will never
> > be a ocmem path.  But of_icc_get(dev, "ocmem") would return -EINVAL
> > instead of -ENODATA.  Just don't bother trying in this case.
> >
> > Fixes: 8e29fb37b301 ("drm/msm: handle for EPROBE_DEFER for of_icc_get")
> > Signed-off-by: Rob Clark <robdclark@chromium.org>
> > ---
> >   drivers/gpu/drm/msm/adreno/adreno_gpu.c | 8 ++++++--
> >   1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> > index 0527e85184e1..c4ac998b90c8 100644
> > --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> > +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> > @@ -979,6 +979,7 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
> >       struct adreno_platform_config *config = dev->platform_data;
> >       struct msm_gpu_config adreno_gpu_config  = { 0 };
> >       struct msm_gpu *gpu = &adreno_gpu->base;
> > +     bool has_interconnect_names = true;
> >       int ret;
> >
> >       adreno_gpu->funcs = funcs;
> > @@ -1005,12 +1006,13 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
> >
> >       /* Check for an interconnect path for the bus */
> >       gpu->icc_path = of_icc_get(dev, "gfx-mem");
> > -     if (!gpu->icc_path) {
> > +     if (IS_ERR_OR_NULL(gpu->icc_path)) {
> >               /*
> >                * Keep compatbility with device trees that don't have an
> >                * interconnect-names property.
> >                */
> >               gpu->icc_path = of_icc_get(dev, NULL);
>
> This is misleading because if it gets a EPROBE_DEFER error (or any other
> error), it will hit this path. Maybe there's a specific error you can
> check for instead to identify the "no-interconnect-names" case?

good point, we should probably instead just explicitly check with
of_find_property("interconnect-names")

fwiw, of_icc_get() returns:

  - NULL if icc disabled, or no "interconnects" property
  - -EINVAL if name!=NULL and no "interconnect-names"
  - and looks like -ENODATA if name!=NULL but no match in
    interconnect-names

The specific error returns aren't really called out in the API comment
block, so not really sure how much we should rely on them not being
implementation details.

BR,
-R

> Also don't think its a good idea to be calling of_icc_get(dev, NULL)
> again when there's a EPROBE_DEFER, the interconnect driver could come up
> between the two calls
>
> > +             has_interconnect_names = false;
> >       }
> >       if (IS_ERR(gpu->icc_path)) {
> >               ret = PTR_ERR(gpu->icc_path);
> > @@ -1018,7 +1020,9 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
> >               return ret;
> >       }
> >
> > -     gpu->ocmem_icc_path = of_icc_get(dev, "ocmem");
> > +     if (has_interconnect_names)
> > +             gpu->ocmem_icc_path = of_icc_get(dev, "ocmem");
> > +
> >       if (IS_ERR(gpu->ocmem_icc_path)) {
> >               ret = PTR_ERR(gpu->ocmem_icc_path);
> >               gpu->ocmem_icc_path = NULL;
> >

Re: [PATCH] drm/msm/adreno: fix gpu probe if no interconnect-names

[Jordan Crouse]

On Wed, Jul 15, 2020 at 12:07:30PM -0700, Rob Clark wrote:
> From: Rob Clark <robdclark@chromium.org>
> 
> If there is no interconnect-names, but there is an interconnects
> property, then of_icc_get(dev, "gfx-mem"); would return an error
> rather than NULL.
> 
> Also, if there is no interconnect-names property, there will never
> be a ocmem path.  But of_icc_get(dev, "ocmem") would return -EINVAL
> instead of -ENODATA.  Just don't bother trying in this case.
> 
> v2: explicity check for interconnect-names property
> 
> Fixes: 8e29fb37b301 ("drm/msm: handle for EPROBE_DEFER for of_icc_get")
> Fixes: 00bb9243d346 ("drm/msm/gpu: add support for ocmem interconnect path")
> Signed-off-by: Rob Clark <robdclark@chromium.org>
> ---
>  drivers/gpu/drm/msm/adreno/adreno_gpu.c | 18 ++++++++++--------
>  1 file changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> index 0527e85184e1..e23641a5ec84 100644
> --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> @@ -1003,22 +1003,23 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
>  	if (ret)
>  		return ret;
>  
> -	/* Check for an interconnect path for the bus */
> -	gpu->icc_path = of_icc_get(dev, "gfx-mem");
> -	if (!gpu->icc_path) {
> -		/*
> -		 * Keep compatbility with device trees that don't have an
> -		 * interconnect-names property.
> -		 */
> +	/*
> +	 * The legacy case, before "interconnect-names", only has a
> +	 * single interconnect path which is equivalent to "gfx-mem"
> +	 */
> +	if (!of_find_property(dev->of_node, "interconnect-names", NULL)) {
>  		gpu->icc_path = of_icc_get(dev, NULL);
> +	} else {
> +		gpu->icc_path = of_icc_get(dev, "gfx-mem");
> +		gpu->ocmem_icc_path = of_icc_get(dev, "ocmem");
>  	}
> +
>  	if (IS_ERR(gpu->icc_path)) {
>  		ret = PTR_ERR(gpu->icc_path);
>  		gpu->icc_path = NULL;
>  		return ret;
>  	}
>  
> -	gpu->ocmem_icc_path = of_icc_get(dev, "ocmem");
>  	if (IS_ERR(gpu->ocmem_icc_path)) {
>  		ret = PTR_ERR(gpu->ocmem_icc_path);
>  		gpu->ocmem_icc_path = NULL;
> @@ -1026,6 +1027,7 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
>  		if (ret != -ENODATA)
>  			return ret;
>  	}
> +

Nit for an extra blank line but otherwise looks fine.  I like this workaround.

With that, Reviewed-by: Jordan Crouse <jcrouse@codeaurora.org>

>  	return 0;
>  }
>  
> -- 
> 2.26.2
> 

-- 
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

[PATCH] drm/msm/adreno: fix gpu probe if no interconnect-names

[Rob Clark]

From: Rob Clark <robdclark@chromium.org>

If there is no interconnect-names, but there is an interconnects
property, then of_icc_get(dev, "gfx-mem"); would return an error
rather than NULL.

Also, if there is no interconnect-names property, there will never
be a ocmem path.  But of_icc_get(dev, "ocmem") would return -EINVAL
instead of -ENODATA.  Just don't bother trying in this case.

v2: explicity check for interconnect-names property

Fixes: 8e29fb37b301 ("drm/msm: handle for EPROBE_DEFER for of_icc_get")
Fixes: 00bb9243d346 ("drm/msm/gpu: add support for ocmem interconnect path")
Signed-off-by: Rob Clark <robdclark@chromium.org>
---
 drivers/gpu/drm/msm/adreno/adreno_gpu.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
index 0527e85184e1..e23641a5ec84 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
@@ -1003,22 +1003,23 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
 	if (ret)
 		return ret;
 
-	/* Check for an interconnect path for the bus */
-	gpu->icc_path = of_icc_get(dev, "gfx-mem");
-	if (!gpu->icc_path) {
-		/*
-		 * Keep compatbility with device trees that don't have an
-		 * interconnect-names property.
-		 */
+	/*
+	 * The legacy case, before "interconnect-names", only has a
+	 * single interconnect path which is equivalent to "gfx-mem"
+	 */
+	if (!of_find_property(dev->of_node, "interconnect-names", NULL)) {
 		gpu->icc_path = of_icc_get(dev, NULL);
+	} else {
+		gpu->icc_path = of_icc_get(dev, "gfx-mem");
+		gpu->ocmem_icc_path = of_icc_get(dev, "ocmem");
 	}
+
 	if (IS_ERR(gpu->icc_path)) {
 		ret = PTR_ERR(gpu->icc_path);
 		gpu->icc_path = NULL;
 		return ret;
 	}
 
-	gpu->ocmem_icc_path = of_icc_get(dev, "ocmem");
 	if (IS_ERR(gpu->ocmem_icc_path)) {
 		ret = PTR_ERR(gpu->ocmem_icc_path);
 		gpu->ocmem_icc_path = NULL;
@@ -1026,6 +1027,7 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
 		if (ret != -ENODATA)
 			return ret;
 	}
+
 	return 0;
 }
 
-- 
2.26.2