[PATCH] staging: ion: Add a default struct device for cma heap

[PATCH] staging: ion: Add a default struct device for cma heap

[Feng Tang]

When trying to use several cma heaps on our platforms,
we met a memory issue due to that the several cma_heaps
are sharing the same "struct device *".

As in current code base, the normal cma heap creating
process is, one platform device is created during boot,
and it will sequentially create cma heaps (usually passing
its own struct device * as a parameter)

For the multiple cma heaps case, there will be one "struct
cma" created for each cma heap, and this "struct cma *" is
saved in dev->cma_area. So the single platform device can't
meet the requirement here.

So this patch add one default device for a cma heap to avoid
sharing the same "struct device", thus fix the issue. And it
doesn't break existing code by only using that default device
when no "struct device *" is passed in.

Also, since the cma framework has been cleaned up, this patch
also add a platform data member to pass the "struct cma*" to
ion_cma_heap_create().

Signed-off-by: Feng Tang <feng.tang@intel.com>
---
 drivers/staging/android/ion/ion.h          |    4 ++++
 drivers/staging/android/ion/ion_cma_heap.c |   20 +++++++++++++++++---
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/android/ion/ion.h b/drivers/staging/android/ion/ion.h
index 443db84..e9af17e 100644
--- a/drivers/staging/android/ion/ion.h
+++ b/drivers/staging/android/ion/ion.h
@@ -45,6 +45,9 @@ struct ion_buffer;
  * @size:	size of the heap in bytes if applicable
  * @align:	required alignment in physical memory if applicable
  * @priv:	private info passed from the board file
+ * @priv2:	when creating CMA heap, platform device should better also
+ *		pass the "struct cma *" info, so that the cma buffer request
+ *		know where to go for the buffer
  *
  * Provided by the board file.
  */
@@ -56,6 +59,7 @@ struct ion_platform_heap {
 	size_t size;
 	ion_phys_addr_t align;
 	void *priv;
+	void *priv2;
 };
 
 /**
diff --git a/drivers/staging/android/ion/ion_cma_heap.c b/drivers/staging/android/ion/ion_cma_heap.c
index f4211f1..b3e8896 100644
--- a/drivers/staging/android/ion/ion_cma_heap.c
+++ b/drivers/staging/android/ion/ion_cma_heap.c
@@ -29,6 +29,7 @@
 struct ion_cma_heap {
 	struct ion_heap heap;
 	struct device *dev;
+	struct device default_dma_dev;
 };
 
 #define to_cma_heap(x) container_of(x, struct ion_cma_heap, heap)
@@ -180,9 +181,22 @@ struct ion_heap *ion_cma_heap_create(struct ion_platform_heap *data)
 		return ERR_PTR(-ENOMEM);
 
 	cma_heap->heap.ops = &ion_cma_ops;
-	/* get device from private heaps data, later it will be
-	 * used to make the link with reserved CMA memory */
-	cma_heap->dev = data->priv;
+
+	/*
+	 * data->priv for cma heap is currently supposed to point
+	 * to a "struct device *"
+	 */
+	if (data->priv) {
+		cma_heap->dev = data->priv;
+	} else {
+		cma_heap->dev = &cma_heap->default_dma_dev;
+		cma_heap->dev->coherent_dma_mask = DMA_BIT_MASK(32);
+		cma_heap->dev->dma_mask = &dev->coherent_dma_mask;
+	}
+
+	/* data->priv2 contains a pointer to struct cma */
+	dev_set_cma_area(cma_heap->dev, data->priv2);
+
 	cma_heap->heap.type = ION_HEAP_TYPE_DMA;
 	return &cma_heap->heap;
 }
-- 
1.7.9.5

Re: [PATCH] staging: ion: Add a default struct device for cma heap

[Michal Nazarewicz]

On Thu, Aug 06 2015, Feng Tang wrote:
> When trying to use several cma heaps on our platforms,
> we met a memory issue due to that the several cma_heaps
> are sharing the same "struct device *".
>
> As in current code base, the normal cma heap creating
> process is, one platform device is created during boot,
> and it will sequentially create cma heaps (usually passing
> its own struct device * as a parameter)
>
> For the multiple cma heaps case, there will be one "struct
> cma" created for each cma heap, and this "struct cma *" is
> saved in dev->cma_area. So the single platform device can't
> meet the requirement here.
>
> So this patch add one default device for a cma heap to avoid
> sharing the same "struct device", thus fix the issue. And it
> doesn't break existing code by only using that default device
> when no "struct device *" is passed in.
>
> Also, since the cma framework has been cleaned up, this patch
> also add a platform data member to pass the "struct cma*" to
> ion_cma_heap_create().
>
> Signed-off-by: Feng Tang <feng.tang@intel.com>

>From CMA’s point of view:

Acked-by: Michal Nazarewicz <mina86@mina86.com>

> ---
>  drivers/staging/android/ion/ion.h          |    4 ++++
>  drivers/staging/android/ion/ion_cma_heap.c |   20 +++++++++++++++++---
>  2 files changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/staging/android/ion/ion.h b/drivers/staging/android/ion/ion.h
> index 443db84..e9af17e 100644
> --- a/drivers/staging/android/ion/ion.h
> +++ b/drivers/staging/android/ion/ion.h
> @@ -45,6 +45,9 @@ struct ion_buffer;
>   * @size:	size of the heap in bytes if applicable
>   * @align:	required alignment in physical memory if applicable
>   * @priv:	private info passed from the board file
> + * @priv2:	when creating CMA heap, platform device should better also
> + *		pass the "struct cma *" info, so that the cma buffer request
> + *		know where to go for the buffer
>   *
>   * Provided by the board file.
>   */
> @@ -56,6 +59,7 @@ struct ion_platform_heap {
>  	size_t size;
>  	ion_phys_addr_t align;
>  	void *priv;
> +	void *priv2;

Why are those void pointers anyway? Perhaps just make them struct device
*dev and struct cma *cma? Especially since priv2 is a bit awkward name.

>  };
>  
>  /**
> diff --git a/drivers/staging/android/ion/ion_cma_heap.c b/drivers/staging/android/ion/ion_cma_heap.c
> index f4211f1..b3e8896 100644
> --- a/drivers/staging/android/ion/ion_cma_heap.c
> +++ b/drivers/staging/android/ion/ion_cma_heap.c
> @@ -29,6 +29,7 @@
>  struct ion_cma_heap {
>  	struct ion_heap heap;
>  	struct device *dev;
> +	struct device default_dma_dev;
>  };
>  
>  #define to_cma_heap(x) container_of(x, struct ion_cma_heap, heap)
> @@ -180,9 +181,22 @@ struct ion_heap *ion_cma_heap_create(struct ion_platform_heap *data)
>  		return ERR_PTR(-ENOMEM);
>  
>  	cma_heap->heap.ops = &ion_cma_ops;
> -	/* get device from private heaps data, later it will be
> -	 * used to make the link with reserved CMA memory */
> -	cma_heap->dev = data->priv;
> +
> +	/*
> +	 * data->priv for cma heap is currently supposed to point
> +	 * to a "struct device *"
> +	 */
> +	if (data->priv) {
> +		cma_heap->dev = data->priv;
> +	} else {
> +		cma_heap->dev = &cma_heap->default_dma_dev;
> +		cma_heap->dev->coherent_dma_mask = DMA_BIT_MASK(32);
> +		cma_heap->dev->dma_mask = &dev->coherent_dma_mask;
> +	}
> +
> +	/* data->priv2 contains a pointer to struct cma */
> +	dev_set_cma_area(cma_heap->dev, data->priv2);

Perhaps:

+	if (data->priv2)
+		dev_set_cma_area(cma_heap->dev, data->priv2);

> +
>  	cma_heap->heap.type = ION_HEAP_TYPE_DMA;
>  	return &cma_heap->heap;
>  }
> -- 
> 1.7.9.5
>

-- 
Best regards,                                         _     _
.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  Michał “mina86” Nazarewicz    (o o)
ooo +--<mpn@google.com>--<xmpp:mina86@jabber.org>--ooO--(_)--Ooo--

Re: [PATCH] staging: ion: Add a default struct device for cma heap

[Feng Tang]

Hi Michal,

Thanks for the review!

On Thu, Aug 06, 2015 at 01:40:28PM +0200, Michal Nazarewicz wrote:
> On Thu, Aug 06 2015, Feng Tang wrote:
> > When trying to use several cma heaps on our platforms,
> > we met a memory issue due to that the several cma_heaps
> > are sharing the same "struct device *".
> >
> > As in current code base, the normal cma heap creating
> > process is, one platform device is created during boot,
> > and it will sequentially create cma heaps (usually passing
> > its own struct device * as a parameter)
> >
> > For the multiple cma heaps case, there will be one "struct
> > cma" created for each cma heap, and this "struct cma *" is
> > saved in dev->cma_area. So the single platform device can't
> > meet the requirement here.
> >
> > So this patch add one default device for a cma heap to avoid
> > sharing the same "struct device", thus fix the issue. And it
> > doesn't break existing code by only using that default device
> > when no "struct device *" is passed in.
> >
> > Also, since the cma framework has been cleaned up, this patch
> > also add a platform data member to pass the "struct cma*" to
> > ion_cma_heap_create().
> >
> > Signed-off-by: Feng Tang <feng.tang@intel.com>
> 
> >From CMA’s point of view:
> 
> Acked-by: Michal Nazarewicz <mina86@mina86.com>
> 
> > ---
> >  drivers/staging/android/ion/ion.h          |    4 ++++
> >  drivers/staging/android/ion/ion_cma_heap.c |   20 +++++++++++++++++---
> >  2 files changed, 21 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/staging/android/ion/ion.h b/drivers/staging/android/ion/ion.h
> > index 443db84..e9af17e 100644
> > --- a/drivers/staging/android/ion/ion.h
> > +++ b/drivers/staging/android/ion/ion.h
> > @@ -45,6 +45,9 @@ struct ion_buffer;
> >   * @size:	size of the heap in bytes if applicable
> >   * @align:	required alignment in physical memory if applicable
> >   * @priv:	private info passed from the board file
> > + * @priv2:	when creating CMA heap, platform device should better also
> > + *		pass the "struct cma *" info, so that the cma buffer request
> > + *		know where to go for the buffer
> >   *
> >   * Provided by the board file.
> >   */
> > @@ -56,6 +59,7 @@ struct ion_platform_heap {
> >  	size_t size;
> >  	ion_phys_addr_t align;
> >  	void *priv;
> > +	void *priv2;
> 
> Why are those void pointers anyway? Perhaps just make them struct device
> *dev and struct cma *cma? Especially since priv2 is a bit awkward name.
 
My initial thought is the same, but as there are several other kinds of ion
heaps which are also using this structure for their own
ion_xxx_heap_create(struct ion_platform_heap *), I gave up using the
explicit "struct cma *", in case other kinds of heaps may need to use
this additional priv2 in future

> > +	 * data->priv for cma heap is currently supposed to point
> > +	 * to a "struct device *"
> > +	 */
> > +	if (data->priv) {
> > +		cma_heap->dev = data->priv;
> > +	} else {
> > +		cma_heap->dev = &cma_heap->default_dma_dev;
> > +		cma_heap->dev->coherent_dma_mask = DMA_BIT_MASK(32);
> > +		cma_heap->dev->dma_mask = &dev->coherent_dma_mask;
> > +	}
> > +
> > +	/* data->priv2 contains a pointer to struct cma */
> > +	dev_set_cma_area(cma_heap->dev, data->priv2);
> 
> Perhaps:
> 
> +	if (data->priv2)
> +		dev_set_cma_area(cma_heap->dev, data->priv2);

Yes, this looks more logical, even though the cma_heap structure is
kzalloced.

Thanks,
Feng

Re: [PATCH] staging: ion: Add a default struct device for cma heap

[Greg Kroah-Hartman]

On Thu, Aug 06, 2015 at 11:25:15PM +0800, Feng Tang wrote:
> Hi Michal,
> 
> Thanks for the review!
> 
> On Thu, Aug 06, 2015 at 01:40:28PM +0200, Michal Nazarewicz wrote:
> > On Thu, Aug 06 2015, Feng Tang wrote:
> > > When trying to use several cma heaps on our platforms,
> > > we met a memory issue due to that the several cma_heaps
> > > are sharing the same "struct device *".
> > >
> > > As in current code base, the normal cma heap creating
> > > process is, one platform device is created during boot,
> > > and it will sequentially create cma heaps (usually passing
> > > its own struct device * as a parameter)
> > >
> > > For the multiple cma heaps case, there will be one "struct
> > > cma" created for each cma heap, and this "struct cma *" is
> > > saved in dev->cma_area. So the single platform device can't
> > > meet the requirement here.
> > >
> > > So this patch add one default device for a cma heap to avoid
> > > sharing the same "struct device", thus fix the issue. And it
> > > doesn't break existing code by only using that default device
> > > when no "struct device *" is passed in.
> > >
> > > Also, since the cma framework has been cleaned up, this patch
> > > also add a platform data member to pass the "struct cma*" to
> > > ion_cma_heap_create().
> > >
> > > Signed-off-by: Feng Tang <feng.tang@intel.com>
> > 
> > >From CMA’s point of view:
> > 
> > Acked-by: Michal Nazarewicz <mina86@mina86.com>
> > 
> > > ---
> > >  drivers/staging/android/ion/ion.h          |    4 ++++
> > >  drivers/staging/android/ion/ion_cma_heap.c |   20 +++++++++++++++++---
> > >  2 files changed, 21 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/drivers/staging/android/ion/ion.h b/drivers/staging/android/ion/ion.h
> > > index 443db84..e9af17e 100644
> > > --- a/drivers/staging/android/ion/ion.h
> > > +++ b/drivers/staging/android/ion/ion.h
> > > @@ -45,6 +45,9 @@ struct ion_buffer;
> > >   * @size:	size of the heap in bytes if applicable
> > >   * @align:	required alignment in physical memory if applicable
> > >   * @priv:	private info passed from the board file
> > > + * @priv2:	when creating CMA heap, platform device should better also
> > > + *		pass the "struct cma *" info, so that the cma buffer request
> > > + *		know where to go for the buffer
> > >   *
> > >   * Provided by the board file.
> > >   */
> > > @@ -56,6 +59,7 @@ struct ion_platform_heap {
> > >  	size_t size;
> > >  	ion_phys_addr_t align;
> > >  	void *priv;
> > > +	void *priv2;
> > 
> > Why are those void pointers anyway? Perhaps just make them struct device
> > *dev and struct cma *cma? Especially since priv2 is a bit awkward name.
>  
> My initial thought is the same, but as there are several other kinds of ion
> heaps which are also using this structure for their own
> ion_xxx_heap_create(struct ion_platform_heap *), I gave up using the
> explicit "struct cma *", in case other kinds of heaps may need to use
> this additional priv2 in future

No, just make it a struct cma *, as that's what it is.  Having multiple
void * is a sign of a very crazy interface.

thanks,

greg k-h