Hi Am 01.03.21 um 23:43 schrieb Oak Zeng:
If tbo.mem.bus.caching is cached, buffer is intended to be mapped as cached from CPU. Map it with ioremap_cache.
Just a question for my understanding: This is on-device memory? Accessing device memory is usually slow. If that memory can be mapped with CPU caching enabled, access will roughly be as fast as for system memory?
Best regards Thomas
This wasn't necessary before as device memory was never mapped as cached from CPU side. It becomes necessary for aldebaran as device memory is mapped cached from CPU. Signed-off-by: Oak Zeng <Oak.Zeng@xxxxxxx> Reviewed-by: Christian Konig <Christian.Koenig@xxxxxxx> --- drivers/gpu/drm/ttm/ttm_bo_util.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c index 031e581..8c65a13 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_util.c +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c @@ -91,6 +91,8 @@ static int ttm_resource_ioremap(struct ttm_device *bdev,if (mem->bus.caching == ttm_write_combined)addr = ioremap_wc(mem->bus.offset, bus_size); + else if (mem->bus.caching == ttm_cached) + addr = ioremap_cache(mem->bus.offset, bus_size); else addr = ioremap(mem->bus.offset, bus_size); if (!addr) { @@ -372,6 +374,9 @@ static int ttm_bo_ioremap(struct ttm_buffer_object *bo, if (mem->bus.caching == ttm_write_combined) map->virtual = ioremap_wc(bo->mem.bus.offset + offset, size); + else if (mem->bus.caching == ttm_cached) + map->virtual = ioremap_cache(bo->mem.bus.offset + offset, + size); else map->virtual = ioremap(bo->mem.bus.offset + offset, size); @@ -490,6 +495,9 @@ int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map) else if (mem->bus.caching == ttm_write_combined) vaddr_iomem = ioremap_wc(mem->bus.offset, bo->base.size); + else if (mem->bus.caching == ttm_cached) + vaddr_iomem = ioremap_cache(mem->bus.offset, + bo->base.size); else vaddr_iomem = ioremap(mem->bus.offset, bo->base.size);
-- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Felix Imendörffer
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