Currently TTM utilizes cached memory regardless of whether the device
have full DMA coherency (can snoop CPU cache).
Save the device's DMA coherency status in struct ttm_device, to allow
further support of devices w/o snooping capability (the capability
missing on at least one part of the transmission between the CPU and the
device).
Signed-off-by: Icenowy Zheng <u...@icenowy.me>
---
drivers/gpu/drm/ttm/ttm_device.c | 2 ++
include/drm/ttm/ttm_device.h | 5 +++++
2 files changed, 7 insertions(+)
diff --git a/drivers/gpu/drm/ttm/ttm_device.c b/drivers/gpu/drm/ttm/ttm_device.c
index 434cf0258000e..b923c14861c1a 100644
--- a/drivers/gpu/drm/ttm/ttm_device.c
+++ b/drivers/gpu/drm/ttm/ttm_device.c
@@ -237,6 +237,8 @@ int ttm_device_init(struct ttm_device *bdev, const struct
ttm_device_funcs *func
list_add_tail(&bdev->device_list, &glob->device_list);
mutex_unlock(&ttm_global_mutex);
+ bdev->dma_coherent = dev->dma_coherent;
+
return 0;
}
EXPORT_SYMBOL(ttm_device_init);
diff --git a/include/drm/ttm/ttm_device.h b/include/drm/ttm/ttm_device.h
index c22f30535c848..9daf7f47d6507 100644
--- a/include/drm/ttm/ttm_device.h
+++ b/include/drm/ttm/ttm_device.h
@@ -225,6 +225,11 @@ struct ttm_device {
*/
const struct ttm_device_funcs *funcs;
+ /**
+ * @dma_coherent: if the device backed is dma-coherent.
+ */
+ bool dma_coherent;
+
/**
* @sysman: Resource manager for the system domain.
* Access via ttm_manager_type.
--
2.45.2
