From: Lucas Stach dev@lynxeye.de
On architectures for which access to GPU memory is non-coherent, caches need to be flushed and invalidated explicitly at the appropriate places. Introduce two small helpers to make things easy for TTM-based drivers.
Signed-off-by: Lucas Stach dev@lynxeye.de Signed-off-by: Alexandre Courbot acourbot@nvidia.com --- drivers/gpu/drm/ttm/ttm_tt.c | 25 +++++++++++++++++++++++++ include/drm/ttm/ttm_bo_driver.h | 28 ++++++++++++++++++++++++++++ 2 files changed, 53 insertions(+)
diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c index 75f319090043..66c16ad35f70 100644 --- a/drivers/gpu/drm/ttm/ttm_tt.c +++ b/drivers/gpu/drm/ttm/ttm_tt.c @@ -38,6 +38,7 @@ #include <linux/swap.h> #include <linux/slab.h> #include <linux/export.h> +#include <linux/dma-mapping.h> #include <drm/drm_cache.h> #include <drm/drm_mem_util.h> #include <drm/ttm/ttm_module.h> @@ -248,6 +249,30 @@ void ttm_dma_tt_fini(struct ttm_dma_tt *ttm_dma) } EXPORT_SYMBOL(ttm_dma_tt_fini);
+void ttm_dma_tt_cache_sync_for_device(struct ttm_dma_tt *ttm_dma, + struct device *dev) +{ + unsigned long i; + + for (i = 0; i < ttm_dma->ttm.num_pages; i++) { + dma_sync_single_for_device(dev, ttm_dma->dma_address[i], + PAGE_SIZE, DMA_TO_DEVICE); + } +} +EXPORT_SYMBOL(ttm_dma_tt_cache_sync_for_device); + +void ttm_dma_tt_cache_sync_for_cpu(struct ttm_dma_tt *ttm_dma, + struct device *dev) +{ + unsigned long i; + + for (i = 0; i < ttm_dma->ttm.num_pages; i++) { + dma_sync_single_for_cpu(dev, ttm_dma->dma_address[i], + PAGE_SIZE, DMA_FROM_DEVICE); + } +} +EXPORT_SYMBOL(ttm_dma_tt_cache_sync_for_cpu); + void ttm_tt_unbind(struct ttm_tt *ttm) { int ret; diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h index a5183da3ef92..52fb709568fc 100644 --- a/include/drm/ttm/ttm_bo_driver.h +++ b/include/drm/ttm/ttm_bo_driver.h @@ -41,6 +41,7 @@ #include <linux/fs.h> #include <linux/spinlock.h> #include <linux/reservation.h> +#include <linux/device.h>
struct ttm_backend_func { /** @@ -690,6 +691,33 @@ extern int ttm_tt_swapout(struct ttm_tt *ttm, */ extern void ttm_tt_unpopulate(struct ttm_tt *ttm);
+/** + * ttm_dma_tt_cache_sync_for_device: + * + * @ttm A struct ttm_tt of the type returned by ttm_dma_tt_init. + * @dev A struct device representing the device to which to sync. + * + * This function will flush the CPU caches on arches where snooping in the + * TT is not available. On fully coherent arches this will turn into an (almost) + * noop. This makes sure that data written by the CPU is visible to the device. + */ +extern void ttm_dma_tt_cache_sync_for_device(struct ttm_dma_tt *ttm_dma, + struct device *dev); + +/** + * ttm_dma_tt_cache_sync_for_cpu: + * + * @ttm A struct ttm_tt of the type returned by ttm_dma_tt_init. + * @dev A struct device representing the device from which to sync. + * + * This function will invalidate the CPU caches on arches where snooping in the + * TT is not available. On fully coherent arches this will turn into an (almost) + * noop. This makes sure that the CPU does not read any stale cached or + * prefetched data. + */ +extern void ttm_dma_tt_cache_sync_for_cpu(struct ttm_dma_tt *ttm_dma, + struct device *dev); + /* * ttm_bo.c */