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/**************************************************************************
*
* 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);
bool drm_need_swiotlb(int dma_bits);
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_LOONGSON64)
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
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