1/* SPDX-License-Identifier: GPL-2.0 OR MIT */
2/**************************************************************************
3 *
4 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
5 * All Rights Reserved.
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a
8 * copy of this software and associated documentation files (the
9 * "Software"), to deal in the Software without restriction, including
10 * without limitation the rights to use, copy, modify, merge, publish,
11 * distribute, sub license, and/or sell copies of the Software, and to
12 * permit persons to whom the Software is furnished to do so, subject to
13 * the following conditions:
14 *
15 * The above copyright notice and this permission notice (including the
16 * next paragraph) shall be included in all copies or substantial portions
17 * of the Software.
18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
22 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
23 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
24 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
25 * USE OR OTHER DEALINGS IN THE SOFTWARE.
26 *
27 **************************************************************************/
28/*
29 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
30 * Jerome Glisse
31 */
32#include <linux/module.h>
33#include <linux/device.h>
34#include <linux/pgtable.h>
35#include <linux/sched.h>
36#include <linux/debugfs.h>
37#include <drm/drm_sysfs.h>
38#include <drm/ttm/ttm_caching.h>
39
40#include "ttm_module.h"
41
42/**
43 * DOC: TTM
44 *
45 * TTM is a memory manager for accelerator devices with dedicated memory.
46 *
47 * The basic idea is that resources are grouped together in buffer objects of
48 * certain size and TTM handles lifetime, movement and CPU mappings of those
49 * objects.
50 *
51 * TODO: Add more design background and information here.
52 */
53
54/**
55 * ttm_prot_from_caching - Modify the page protection according to the
56 * ttm cacing mode
57 * @caching: The ttm caching mode
58 * @tmp: The original page protection
59 *
60 * Return: The modified page protection
61 */
62pgprot_t ttm_prot_from_caching(enum ttm_caching caching, pgprot_t tmp)
63{
64 /* Cached mappings need no adjustment */
65 if (caching == ttm_cached)
66 return tmp;
67
68#if defined(__i386__) || defined(__x86_64__)
69 if (caching == ttm_write_combined)
70 tmp = pgprot_writecombine(prot: tmp);
71#ifndef CONFIG_UML
72 else if (boot_cpu_data.x86 > 3)
73 tmp = pgprot_noncached(tmp);
74#endif /* CONFIG_UML */
75#endif /* __i386__ || __x86_64__ */
76#if defined(__ia64__) || defined(__arm__) || defined(__aarch64__) || \
77 defined(__powerpc__) || defined(__mips__) || defined(__loongarch__) || \
78 defined(__riscv)
79 if (caching == ttm_write_combined)
80 tmp = pgprot_writecombine(tmp);
81 else
82 tmp = pgprot_noncached(tmp);
83#endif
84#if defined(__sparc__)
85 tmp = pgprot_noncached(tmp);
86#endif
87 return tmp;
88}
89
90MODULE_AUTHOR("Thomas Hellstrom, Jerome Glisse");
91MODULE_DESCRIPTION("TTM memory manager subsystem (for DRM device)");
92MODULE_LICENSE("GPL and additional rights");
93

source code of linux/drivers/gpu/drm/ttm/ttm_module.c