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1/**************************************************************************2 *3 * Copyright 2009 Red Hat Inc.4 * All Rights Reserved.5 *6 * Permission is hereby granted, free of charge, to any person obtaining a7 * copy of this software and associated documentation files (the8 * "Software"), to deal in the Software without restriction, including9 * without limitation the rights to use, copy, modify, merge, publish,10 * distribute, sub license, and/or sell copies of the Software, and to11 * permit persons to whom the Software is furnished to do so, subject to12 * the following conditions:13 *14 * The above copyright notice and this permission notice (including the15 * next paragraph) shall be included in all copies or substantial portions16 * of the Software.17 *18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE24 * USE OR OTHER DEALINGS IN THE SOFTWARE.25 *26 *27 **************************************************************************/28/*29 * Authors:30 * Dave Airlie <airlied@redhat.com>31 */32 33#ifndef _DRM_CACHE_H_34#define _DRM_CACHE_H_35 36#include <linux/scatterlist.h>37 38struct iosys_map;39 40void drm_clflush_pages(struct page *pages[], unsigned long num_pages);41void drm_clflush_sg(struct sg_table *st);42void drm_clflush_virt_range(void *addr, unsigned long length);43bool drm_need_swiotlb(int dma_bits);44 45 46static inline bool drm_arch_can_wc_memory(void)47{48#if defined(CONFIG_PPC) && !defined(CONFIG_NOT_COHERENT_CACHE)49 return false;50#elif defined(CONFIG_MIPS) && defined(CONFIG_CPU_LOONGSON64)51 return false;52#elif defined(CONFIG_ARM) || defined(CONFIG_ARM64)53 /*54 * The DRM driver stack is designed to work with cache coherent devices55 * only, but permits an optimization to be enabled in some cases, where56 * for some buffers, both the CPU and the GPU use uncached mappings,57 * removing the need for DMA snooping and allocation in the CPU caches.58 *59 * The use of uncached GPU mappings relies on the correct implementation60 * of the PCIe NoSnoop TLP attribute by the platform, otherwise the GPU61 * will use cached mappings nonetheless. On x86 platforms, this does not62 * seem to matter, as uncached CPU mappings will snoop the caches in any63 * case. However, on ARM and arm64, enabling this optimization on a64 * platform where NoSnoop is ignored results in loss of coherency, which65 * breaks correct operation of the device. Since we have no way of66 * detecting whether NoSnoop works or not, just disable this67 * optimization entirely for ARM and arm64.68 */69 return false;70#elif defined(CONFIG_LOONGARCH)71 /*72 * LoongArch maintains cache coherency in hardware, but its WUC attribute73 * (Weak-ordered UnCached, which is similar to WC) is out of the scope of74 * cache coherency machanism. This means WUC can only used for write-only75 * memory regions.76 */77 return false;78#else79 return true;80#endif81}82 83void drm_memcpy_init_early(void);84 85void drm_memcpy_from_wc(struct iosys_map *dst,86 const struct iosys_map *src,87 unsigned long len);88#endif89