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.
CC: Smitha T Murthy <smitha.t@xxxxxxxxxxx>
CC: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
CC: Rob Herring <robh@xxxxxxxxxx>
Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>
---
drivers/media/platform/s5p-mfc/s5p_mfc.c | 7 +++++++
drivers/of/of_reserved_mem.c | 4 ----
2 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/media/platform/s5p-mfc/s5p_mfc.c b/drivers/media/platform/s5p-mfc/s5p_mfc.c
index 927a1235408d..77eb4a4511c1 100644
--- 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 895c83e0c7b6..4ef6f4485335 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -350,10 +350,6 @@ 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 {
--
2.19.0.dirty
