drm/ttm/ttm_caching.h

0001 /*
0002  * Copyright 2020 Advanced Micro Devices, Inc.
0003  *
0004  * Permission is hereby granted, free of charge, to any person obtaining a
0005  * copy of this software and associated documentation files (the "Software"),
0006  * to deal in the Software without restriction, including without limitation
0007  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
0008  * and/or sell copies of the Software, and to permit persons to whom the
0009  * Software is furnished to do so, subject to the following conditions:
0010  *
0011  * The above copyright notice and this permission notice shall be included in
0012  * all copies or substantial portions of the Software.
0013  *
0014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
0015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
0016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
0017  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
0018  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
0019  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
0020  * OTHER DEALINGS IN THE SOFTWARE.
0021  *
0022  * Authors: Christian König
0023  */
0024
0025 #ifndef _TTM_CACHING_H_
0026 #define _TTM_CACHING_H_
0027
0028 #define TTM_NUM_CACHING_TYPES   3
0029
0030 /**
0031  * enum ttm_caching - CPU caching and BUS snooping behavior.
0032  */
0033 enum ttm_caching {
0034     /**
0035      * @ttm_uncached: Most defensive option for device mappings,
0036      * don't even allow write combining.
0037      */
0038     ttm_uncached,
0039
0040     /**
0041      * @ttm_write_combined: Don't cache read accesses, but allow at least
0042      * writes to be combined.
0043      */
0044     ttm_write_combined,
0045
0046     /**
0047      * @ttm_cached: Fully cached like normal system memory, requires that
0048      * devices snoop the CPU cache on accesses.
0049      */
0050     ttm_cached
0051 };
0052
0053 pgprot_t ttm_prot_from_caching(enum ttm_caching caching, pgprot_t tmp);
0054
0055 #endif