1/*	$NetBSD: drm_memory.c,v 1.3 2021/12/18 23:44:57 riastradh Exp $	*/
2
3/*
4 * \file drm_memory.c
5 * Memory management wrappers for DRM
6 *
7 * \author Rickard E. (Rik) Faith <faith@valinux.com>
8 * \author Gareth Hughes <gareth@valinux.com>
9 */
10
11/*
12 * Created: Thu Feb  4 14:00:34 1999 by faith@valinux.com
13 *
14 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
15 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
16 * All Rights Reserved.
17 *
18 * Permission is hereby granted, free of charge, to any person obtaining a
19 * copy of this software and associated documentation files (the "Software"),
20 * to deal in the Software without restriction, including without limitation
21 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
22 * and/or sell copies of the Software, and to permit persons to whom the
23 * Software is furnished to do so, subject to the following conditions:
24 *
25 * The above copyright notice and this permission notice (including the next
26 * paragraph) shall be included in all copies or substantial portions of the
27 * Software.
28 *
29 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
30 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
31 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
32 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
33 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
34 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
35 * OTHER DEALINGS IN THE SOFTWARE.
36 */
37
38#include <sys/cdefs.h>
39__KERNEL_RCSID(0, "$NetBSD: drm_memory.c,v 1.3 2021/12/18 23:44:57 riastradh Exp $");
40
41#include <linux/export.h>
42#include <linux/highmem.h>
43#include <linux/pci.h>
44#include <linux/vmalloc.h>
45#include <xen/xen.h>
46
47#include <drm/drm_agpsupport.h>
48#include <drm/drm_cache.h>
49#include <drm/drm_device.h>
50
51#include "drm_legacy.h"
52
53#if IS_ENABLED(CONFIG_AGP)
54
55#ifdef HAVE_PAGE_AGP
56# include <asm/agp.h>
57#else
58# ifdef __powerpc__
59#  define PAGE_AGP	pgprot_noncached_wc(PAGE_KERNEL)
60# else
61#  define PAGE_AGP	PAGE_KERNEL
62# endif
63#endif
64
65static void *agp_remap(unsigned long offset, unsigned long size,
66		       struct drm_device *dev)
67{
68	unsigned long i, num_pages =
69	    PAGE_ALIGN(size) / PAGE_SIZE;
70	struct drm_agp_mem *agpmem;
71	struct page **page_map;
72	struct page **phys_page_map;
73	void *addr;
74
75	size = PAGE_ALIGN(size);
76
77#ifdef __alpha__
78	offset -= dev->hose->mem_space->start;
79#endif
80
81	list_for_each_entry(agpmem, &dev->agp->memory, head)
82		if (agpmem->bound <= offset
83		    && (agpmem->bound + (agpmem->pages << PAGE_SHIFT)) >=
84		    (offset + size))
85			break;
86	if (&agpmem->head == &dev->agp->memory)
87		return NULL;
88
89	/*
90	 * OK, we're mapping AGP space on a chipset/platform on which memory accesses by
91	 * the CPU do not get remapped by the GART.  We fix this by using the kernel's
92	 * page-table instead (that's probably faster anyhow...).
93	 */
94	/* note: use vmalloc() because num_pages could be large... */
95	page_map = vmalloc(array_size(num_pages, sizeof(struct page *)));
96	if (!page_map)
97		return NULL;
98
99	phys_page_map = (agpmem->memory->pages + (offset - agpmem->bound) / PAGE_SIZE);
100	for (i = 0; i < num_pages; ++i)
101		page_map[i] = phys_page_map[i];
102	addr = vmap(page_map, num_pages, VM_IOREMAP, PAGE_AGP);
103	vfree(page_map);
104
105	return addr;
106}
107
108/** Wrapper around agp_free_memory() */
109void drm_free_agp(struct agp_memory *handle, int pages)
110{
111	agp_free_memory(handle);
112}
113
114/** Wrapper around agp_bind_memory() */
115int drm_bind_agp(struct agp_memory *handle, unsigned int start)
116{
117	return agp_bind_memory(handle, start);
118}
119
120/** Wrapper around agp_unbind_memory() */
121int drm_unbind_agp(struct agp_memory *handle)
122{
123	return agp_unbind_memory(handle);
124}
125
126#else /*  CONFIG_AGP  */
127static inline void *agp_remap(unsigned long offset, unsigned long size,
128			      struct drm_device *dev)
129{
130	return NULL;
131}
132
133#endif /* CONFIG_AGP */
134
135void drm_legacy_ioremap(struct drm_local_map *map, struct drm_device *dev)
136{
137	if (dev->agp && dev->agp->cant_use_aperture && map->type == _DRM_AGP)
138		map->handle = agp_remap(map->offset, map->size, dev);
139	else
140		map->handle = ioremap(map->offset, map->size);
141}
142EXPORT_SYMBOL(drm_legacy_ioremap);
143
144void drm_legacy_ioremap_wc(struct drm_local_map *map, struct drm_device *dev)
145{
146	if (dev->agp && dev->agp->cant_use_aperture && map->type == _DRM_AGP)
147		map->handle = agp_remap(map->offset, map->size, dev);
148	else
149		map->handle = ioremap_wc(map->offset, map->size);
150}
151EXPORT_SYMBOL(drm_legacy_ioremap_wc);
152
153void drm_legacy_ioremapfree(struct drm_local_map *map, struct drm_device *dev)
154{
155	if (!map->handle || !map->size)
156		return;
157
158	if (dev->agp && dev->agp->cant_use_aperture && map->type == _DRM_AGP)
159		vunmap(map->handle);
160	else
161		iounmap(map->handle);
162}
163EXPORT_SYMBOL(drm_legacy_ioremapfree);
164
165bool drm_need_swiotlb(int dma_bits)
166{
167	struct resource *tmp;
168	resource_size_t max_iomem = 0;
169
170	/*
171	 * Xen paravirtual hosts require swiotlb regardless of requested dma
172	 * transfer size.
173	 *
174	 * NOTE: Really, what it requires is use of the dma_alloc_coherent
175	 *       allocator used in ttm_dma_populate() instead of
176	 *       ttm_populate_and_map_pages(), which bounce buffers so much in
177	 *       Xen it leads to swiotlb buffer exhaustion.
178	 */
179	if (xen_pv_domain())
180		return true;
181
182	/*
183	 * Enforce dma_alloc_coherent when memory encryption is active as well
184	 * for the same reasons as for Xen paravirtual hosts.
185	 */
186	if (mem_encrypt_active())
187		return true;
188
189	for (tmp = iomem_resource.child; tmp; tmp = tmp->sibling) {
190		max_iomem = max(max_iomem,  tmp->end);
191	}
192
193	return max_iomem > ((u64)1 << dma_bits);
194}
195EXPORT_SYMBOL(drm_need_swiotlb);
196