[RESEND] media: s5p-mfc: Fix memdev DMA configuration
Commit Message
Having of_reserved_mem_device_init() forcibly reconfigure DMA for all
callers, potentially overriding the work done by a bus-specific
.dma_configure method earlier, is at best a bad idea and at worst
actively harmful. If drivers really need virtual devices to own
dma-coherent memory, they should explicitly configure those devices
based on the appropriate firmware node as they create them.
It looks like the only driver not passing in a proper OF platform device
is s5p-mfc, so move the rogue of_dma_configure() call into that driver
where it logically belongs.
Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
Hi Rob, Frank,
Bit of an old one bit it's rebased cleanly - Mauro reckoned[1] this
would suit the OF tree better than media, are you happy to pick it up?
Thanks,
Robin.
[1] https://patchwork.kernel.org/patch/10598085/
drivers/media/platform/s5p-mfc/s5p_mfc.c | 7 +++++++
drivers/of/of_reserved_mem.c | 4 ----
2 files changed, 7 insertions(+), 4 deletions(-)
Comments
On Mon, Jan 14, 2019 at 03:14:14PM +0000, Robin Murphy wrote:
> Having of_reserved_mem_device_init() forcibly reconfigure DMA for all
> callers, potentially overriding the work done by a bus-specific
> .dma_configure method earlier, is at best a bad idea and at worst
> actively harmful. If drivers really need virtual devices to own
> dma-coherent memory, they should explicitly configure those devices
> based on the appropriate firmware node as they create them.
>
> It looks like the only driver not passing in a proper OF platform device
> is s5p-mfc, so move the rogue of_dma_configure() call into that driver
> where it logically belongs.
>
> Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Acked-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> ---
>
> Hi Rob, Frank,
>
> Bit of an old one bit it's rebased cleanly - Mauro reckoned[1] this
> would suit the OF tree better than media, are you happy to pick it up?
Applied.
Rob
@@ -1094,6 +1094,13 @@ static struct device *s5p_mfc_alloc_memdev(struct device *dev,
child->dma_mask = dev->dma_mask;
child->release = s5p_mfc_memdev_release;
+ /*
+ * The memdevs are not proper OF platform devices, so in order for them
+ * to be treated as valid DMA masters we need a bit of a hack to force
+ * them to inherit the MFC node's DMA configuration.
+ */
+ of_dma_configure(child, dev->of_node, true);
+
if (device_add(child) == 0) {
ret = of_reserved_mem_device_init_by_idx(child, dev->of_node,
idx);
@@ -340,10 +340,6 @@ int of_reserved_mem_device_init_by_idx(struct device *dev,
mutex_lock(&of_rmem_assigned_device_mutex);
list_add(&rd->list, &of_rmem_assigned_device_list);
mutex_unlock(&of_rmem_assigned_device_mutex);
- /* ensure that dma_ops is set for virtual devices
- * using reserved memory
- */
- of_dma_configure(dev, np, true);
dev_info(dev, "assigned reserved memory node %s\n", rmem->name);
} else {