mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-11-01 17:08:10 +00:00
439057ec3b
LoongArch maintains cache coherency in hardware, but its WUC attribute (Weak-ordered UnCached, which is similar to WC) is out of the scope of cache coherency machanism. This means WUC can only used for write-only memory regions. Cc: Daniel Vetter <daniel@ffwll.ch> Cc: dri-devel@lists.freedesktop.org Reviewed-by: WANG Xuerui <git@xen0n.name> Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
88 lines
3.3 KiB
C
88 lines
3.3 KiB
C
/**************************************************************************
|
|
*
|
|
* 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>
|
|
|
|
struct iosys_map;
|
|
|
|
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;
|
|
#elif defined(CONFIG_LOONGARCH)
|
|
/*
|
|
* LoongArch maintains cache coherency in hardware, but its WUC attribute
|
|
* (Weak-ordered UnCached, which is similar to WC) is out of the scope of
|
|
* cache coherency machanism. This means WUC can only used for write-only
|
|
* memory regions.
|
|
*/
|
|
return false;
|
|
#else
|
|
return true;
|
|
#endif
|
|
}
|
|
|
|
void drm_memcpy_init_early(void);
|
|
|
|
void drm_memcpy_from_wc(struct iosys_map *dst,
|
|
const struct iosys_map *src,
|
|
unsigned long len);
|
|
#endif
|