On 02/24/2016 12:28 AM, Thierry Reding wrote:
- PGP Signed by an unknown key
On Tue, Feb 23, 2016 at 03:25:53PM +0900, Alexandre Courbot wrote:
The current settings leaves the DRM device's dma_ops field NULL, which makes it use the dummy DMA ops on arm64 and return an error whenever we try to import a buffer. Call of_dma_configure() with a NULL node (since the device is not spawn from the device tree) so that arch_setup_dma_ops() is called and sets the default ioswtlb DMA ops.
Signed-off-by: Alexandre Courbot acourbot@nvidia.com
drivers/gpu/drm/tegra/drm.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c index d347188bf8f4..bc0555adecaf 100644 --- a/drivers/gpu/drm/tegra/drm.c +++ b/drivers/gpu/drm/tegra/drm.c @@ -9,6 +9,7 @@
#include <linux/host1x.h> #include <linux/iommu.h> +#include <linux/of_device.h>
#include <drm/drm_atomic.h> #include <drm/drm_atomic_helper.h> @@ -990,6 +991,7 @@ static int host1x_drm_probe(struct host1x_device *dev) return -ENOMEM;
dev_set_drvdata(&dev->dev, drm);
- of_dma_configure(drm->dev, NULL);
Looking at the various pieces, I think this really belongs in host1x_device_add() (see drivers/gpu/host1x/bus.c) where it can replace the open-coded setting of DMA and coherent DMA masks. Also why can't we pass the correct device tree node here? The DRM device is a virtual device that hangs off the host1x device, so I think it could use the same device tree node as the host1x device.
Something like the below (untested).
You're right, that looks like a much better place to do this. of_dma_configure() is called at the bus level (platform and PCI), so it makes sense to do it from host1x too.