| /************************************************************************** |
| * |
| * Copyright 2009 Red Hat Inc. |
| * All Rights Reserved. |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a |
| * copy of this software and associated documentation files (the |
| * "Software"), to deal in the Software without restriction, including |
| * without limitation the rights to use, copy, modify, merge, publish, |
| * distribute, sub license, and/or sell copies of the Software, and to |
| * permit persons to whom the Software is furnished to do so, subject to |
| * the following conditions: |
| * |
| * The above copyright notice and this permission notice (including the |
| * next paragraph) shall be included in all copies or substantial portions |
| * of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL |
| * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, |
| * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR |
| * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE |
| * USE OR OTHER DEALINGS IN THE SOFTWARE. |
| * |
| * |
| **************************************************************************/ |
| /* |
| * Authors: |
| * Dave Airlie <airlied@redhat.com> |
| */ |
| |
| #ifndef _DRM_CACHE_H_ |
| #define _DRM_CACHE_H_ |
| |
| #include <linux/scatterlist.h> |
| |
| void drm_clflush_pages(struct page *pages[], unsigned long num_pages); |
| void drm_clflush_sg(struct sg_table *st); |
| void drm_clflush_virt_range(void *addr, unsigned long length); |
| u64 drm_get_max_iomem(void); |
| |
| |
| static inline bool drm_arch_can_wc_memory(void) |
| { |
| #if defined(CONFIG_PPC) && !defined(CONFIG_NOT_COHERENT_CACHE) |
| return false; |
| #elif defined(CONFIG_MIPS) && defined(CONFIG_CPU_LOONGSON3) |
| return false; |
| #elif defined(CONFIG_ARM) || defined(CONFIG_ARM64) |
| /* |
| * The DRM driver stack is designed to work with cache coherent devices |
| * only, but permits an optimization to be enabled in some cases, where |
| * for some buffers, both the CPU and the GPU use uncached mappings, |
| * removing the need for DMA snooping and allocation in the CPU caches. |
| * |
| * The use of uncached GPU mappings relies on the correct implementation |
| * of the PCIe NoSnoop TLP attribute by the platform, otherwise the GPU |
| * will use cached mappings nonetheless. On x86 platforms, this does not |
| * seem to matter, as uncached CPU mappings will snoop the caches in any |
| * case. However, on ARM and arm64, enabling this optimization on a |
| * platform where NoSnoop is ignored results in loss of coherency, which |
| * breaks correct operation of the device. Since we have no way of |
| * detecting whether NoSnoop works or not, just disable this |
| * optimization entirely for ARM and arm64. |
| */ |
| return false; |
| #else |
| return true; |
| #endif |
| } |
| |
| #endif |