On Fri, Aug 30, 2024 at 10:47 AM Christian König
<christian.koenig@xxxxxxx> wrote:
>
> Am 30.08.24 um 09:03 schrieb Jens Wiklander:
> > Add a no_map attribute to struct restricted_heap_attachment and struct
> > restricted_heap to skip the call to dma_map_sgtable() if set. This
> > avoids trying to map a dma-buf that doens't refer to memory accessible
> > by the kernel.
>
> You seem to have a misunderstanding here dma_map_sgtable() is called to
> map a table into IOMMU and not any kernel address space.
>
> So please explain why you need that?
You're right, I had misunderstood dma_map_sgtable(). There's no need
for the no_map attribute, so I'll remove it.
Perhaps you have a suggestion on how to fix a problem when using
dma_map_sgtable()?
Without it, I'll have to assign a pointer to teedev->dev.dma_mask when
using the restricted heap with the OP-TEE driver or there will be a
warning in __dma_map_sg_attrs() ending with a failure when trying to
register the dma-buf fd. OP-TEE is probed with a platform device, and
taking the dma_mask pointer from that device works. Is that a good
approach or is there a better way of assigning dma_mask?
Thanks,
Jens
>
> Regards,
> Christian.
>
> >
> > Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
> > ---
> > drivers/dma-buf/heaps/restricted_heap.c | 17 +++++++++++++----
> > drivers/dma-buf/heaps/restricted_heap.h | 2 ++
> > 2 files changed, 15 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/dma-buf/heaps/restricted_heap.c b/drivers/dma-buf/heaps/restricted_heap.c
> > index 8bc8a5e3f969..4bf28e3727ca 100644
> > --- a/drivers/dma-buf/heaps/restricted_heap.c
> > +++ b/drivers/dma-buf/heaps/restricted_heap.c
> > @@ -16,6 +16,7 @@
> > struct restricted_heap_attachment {
> > struct sg_table *table;
> > struct device *dev;
> > + bool no_map;
> > };
> >
> > static int
> > @@ -54,6 +55,8 @@ restricted_heap_memory_free(struct restricted_heap *rheap, struct restricted_buf
> > static int restricted_heap_attach(struct dma_buf *dmabuf, struct dma_buf_attachment *attachment)
> > {
> > struct restricted_buffer *restricted_buf = dmabuf->priv;
> > + struct dma_heap *heap = restricted_buf->heap;
> > + struct restricted_heap *rheap = dma_heap_get_drvdata(heap);
> > struct restricted_heap_attachment *a;
> > struct sg_table *table;
> >
> > @@ -70,6 +73,7 @@ static int restricted_heap_attach(struct dma_buf *dmabuf, struct dma_buf_attachm
> > sg_dma_mark_restricted(table->sgl);
> > a->table = table;
> > a->dev = attachment->dev;
> > + a->no_map = rheap->no_map;
> > attachment->priv = a;
> >
> > return 0;
> > @@ -92,9 +96,12 @@ restricted_heap_map_dma_buf(struct dma_buf_attachment *attachment,
> > struct sg_table *table = a->table;
> > int ret;
> >
> > - ret = dma_map_sgtable(attachment->dev, table, direction, DMA_ATTR_SKIP_CPU_SYNC);
> > - if (ret)
> > - return ERR_PTR(ret);
> > + if (!a->no_map) {
> > + ret = dma_map_sgtable(attachment->dev, table, direction,
> > + DMA_ATTR_SKIP_CPU_SYNC);
> > + if (ret)
> > + return ERR_PTR(ret);
> > + }
> > return table;
> > }
> >
> > @@ -106,7 +113,9 @@ restricted_heap_unmap_dma_buf(struct dma_buf_attachment *attachment, struct sg_t
> >
> > WARN_ON(a->table != table);
> >
> > - dma_unmap_sgtable(attachment->dev, table, direction, DMA_ATTR_SKIP_CPU_SYNC);
> > + if (!a->no_map)
> > + dma_unmap_sgtable(attachment->dev, table, direction,
> > + DMA_ATTR_SKIP_CPU_SYNC);
> > }
> >
> > static int
> > diff --git a/drivers/dma-buf/heaps/restricted_heap.h b/drivers/dma-buf/heaps/restricted_heap.h
> > index 7dec4b8a471b..94cc0842f70d 100644
> > --- a/drivers/dma-buf/heaps/restricted_heap.h
> > +++ b/drivers/dma-buf/heaps/restricted_heap.h
> > @@ -27,6 +27,8 @@ struct restricted_heap {
> > unsigned long cma_paddr;
> > unsigned long cma_size;
> >
> > + bool no_map;
> > +
> > void *priv_data;
> > };
> >
>
