drm/etnaviv: request pages from DMA32 zone when needed

Some Vivante GPUs are found in systems that have interconnects restricted
to 32 address bits, but may have system memory mapped above the 4GB mark.
As this region isn't accessible to the GPU via DMA any GPU memory allocated
in the upper part needs to go through SWIOTLB bounce buffering. This kills
performance if it happens too often, as well as overrunning the available
bounce buffer space, as the GPU buffer may stay mapped for a long time.

Avoid bounce buffering by checking the addressing restrictions. If the
GPU is unable to access memory above the 4GB mark, request our SHM buffers
to be located in the DMA32 zone.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.h b/drivers/gpu/drm/etnaviv/etnaviv_drv.h
index efc656efeb0f..4d8dc9236e5f 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_drv.h
+++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.h
@@ -35,6 +35,7 @@ struct etnaviv_drm_private {
 	int num_gpus;
 	struct device_dma_parameters dma_parms;
 	struct etnaviv_gpu *gpu[ETNA_MAX_PIPES];
+	gfp_t shm_gfp_mask;
 
 	struct etnaviv_cmdbuf_suballoc *cmdbuf_suballoc;
 	struct etnaviv_iommu_global *mmu_global;