media: s5p-mfc: Fix memdev DMA configuration

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>
Signed-off-by: Rob Herring <robh@kernel.org>

diff --git a/drivers/media/platform/s5p-mfc/s5p_mfc.c b/drivers/media/platform/s5p-mfc/s5p_mfc.c
index 8a5ba3b..6db3370 100644 (file)
--- a/drivers/media/platform/s5p-mfc/s5p_mfc.c
+++ b/drivers/media/platform/s5p-mfc/s5p_mfc.c
@@ -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);

diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 1977ee0..9e02a5d 100644 (file)
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -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 {