1/*
  2 * Copyright © 2014-2016 Intel Corporation
  3 *
  4 * Permission is hereby granted, free of charge, to any person obtaining a
  5 * copy of this software and associated documentation files (the "Software"),
  6 * to deal in the Software without restriction, including without limitation
  7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  8 * and/or sell copies of the Software, and to permit persons to whom the
  9 * Software is furnished to do so, subject to the following conditions:
 10 *
 11 * The above copyright notice and this permission notice (including the next
 12 * paragraph) shall be included in all copies or substantial portions of the
 13 * Software.
 14 *
 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 21 * IN THE SOFTWARE.
 22 *
 23 */
 24
 25#include <drm/drmP.h>
 26#include <drm/i915_drm.h>
 27#include "i915_drv.h"
 28
 29#define QUIET (__GFP_NORETRY | __GFP_NOWARN)
 30
 31/* convert swiotlb segment size into sensible units (pages)! */
 32#define IO_TLB_SEGPAGES (IO_TLB_SEGSIZE << IO_TLB_SHIFT >> PAGE_SHIFT)
 33
 34static void internal_free_pages(struct sg_table *st)
 35{
 36	struct scatterlist *sg;
 37
 38	for (sg = st->sgl; sg; sg = __sg_next(sg))
 39		__free_pages(sg_page(sg), get_order(sg->length));
 40
 41	sg_free_table(st);
 42	kfree(st);
 43}
 44
 45static struct sg_table *
 46i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj)
 47{
 48	struct drm_i915_private *i915 = to_i915(obj->base.dev);
 49	struct sg_table *st;
 50	struct scatterlist *sg;
 51	unsigned int npages;
 52	int max_order;
 53	gfp_t gfp;
 54
 55	max_order = MAX_ORDER;
 56#ifdef CONFIG_SWIOTLB
 57	if (swiotlb_nr_tbl()) {
 58		unsigned int max_segment;
 59
 60		max_segment = swiotlb_max_segment();
 61		if (max_segment) {
 62			max_segment = max_t(unsigned int, max_segment,
 63					    PAGE_SIZE) >> PAGE_SHIFT;
 64			max_order = min(max_order, ilog2(max_segment));
 65		}
 66	}
 67#endif
 68
 69	gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_RECLAIMABLE;
 70	if (IS_CRESTLINE(i915) || IS_BROADWATER(i915)) {
 71		/* 965gm cannot relocate objects above 4GiB. */
 72		gfp &= ~__GFP_HIGHMEM;
 73		gfp |= __GFP_DMA32;
 74	}
 75
 76create_st:
 77	st = kmalloc(sizeof(*st), GFP_KERNEL);
 78	if (!st)
 79		return ERR_PTR(-ENOMEM);
 80
 81	npages = obj->base.size / PAGE_SIZE;
 82	if (sg_alloc_table(st, npages, GFP_KERNEL)) {
 83		kfree(st);
 84		return ERR_PTR(-ENOMEM);
 85	}
 86
 87	sg = st->sgl;
 88	st->nents = 0;
 89
 90	do {
 91		int order = min(fls(npages) - 1, max_order);
 92		struct page *page;
 93
 94		do {
 95			page = alloc_pages(gfp | (order ? QUIET : 0), order);
 96			if (page)
 97				break;
 98			if (!order--)
 99				goto err;
100
101			/* Limit subsequent allocations as well */
102			max_order = order;
103		} while (1);
104
105		sg_set_page(sg, page, PAGE_SIZE << order, 0);
106		st->nents++;
107
108		npages -= 1 << order;
109		if (!npages) {
110			sg_mark_end(sg);
111			break;
112		}
113
114		sg = __sg_next(sg);
115	} while (1);
116
117	if (i915_gem_gtt_prepare_pages(obj, st)) {
118		/* Failed to dma-map try again with single page sg segments */
119		if (get_order(st->sgl->length)) {
120			internal_free_pages(st);
121			max_order = 0;
122			goto create_st;
123		}
124		goto err;
125	}
126
127	/* Mark the pages as dontneed whilst they are still pinned. As soon
128	 * as they are unpinned they are allowed to be reaped by the shrinker,
129	 * and the caller is expected to repopulate - the contents of this
130	 * object are only valid whilst active and pinned.
131	 */
132	obj->mm.madv = I915_MADV_DONTNEED;
133	return st;
134
135err:
136	sg_mark_end(sg);
137	internal_free_pages(st);
138	return ERR_PTR(-ENOMEM);
139}
140
141static void i915_gem_object_put_pages_internal(struct drm_i915_gem_object *obj,
142					       struct sg_table *pages)
143{
144	i915_gem_gtt_finish_pages(obj, pages);
145	internal_free_pages(pages);
146
147	obj->mm.dirty = false;
148	obj->mm.madv = I915_MADV_WILLNEED;
149}
150
151static const struct drm_i915_gem_object_ops i915_gem_object_internal_ops = {
152	.flags = I915_GEM_OBJECT_HAS_STRUCT_PAGE |
153		 I915_GEM_OBJECT_IS_SHRINKABLE,
154	.get_pages = i915_gem_object_get_pages_internal,
155	.put_pages = i915_gem_object_put_pages_internal,
156};
157
158/**
159 * Creates a new object that wraps some internal memory for private use.
160 * This object is not backed by swappable storage, and as such its contents
161 * are volatile and only valid whilst pinned. If the object is reaped by the
162 * shrinker, its pages and data will be discarded. Equally, it is not a full
163 * GEM object and so not valid for access from userspace. This makes it useful
164 * for hardware interfaces like ringbuffers (which are pinned from the time
165 * the request is written to the time the hardware stops accessing it), but
166 * not for contexts (which need to be preserved when not active for later
167 * reuse). Note that it is not cleared upon allocation.
168 */
169struct drm_i915_gem_object *
170i915_gem_object_create_internal(struct drm_i915_private *i915,
171				unsigned int size)
172{
173	struct drm_i915_gem_object *obj;
174
175	obj = i915_gem_object_alloc(&i915->drm);
176	if (!obj)
177		return ERR_PTR(-ENOMEM);
178
179	drm_gem_private_object_init(&i915->drm, &obj->base, size);
180	i915_gem_object_init(obj, &i915_gem_object_internal_ops);
181
182	obj->base.write_domain = I915_GEM_DOMAIN_CPU;
183	obj->base.read_domains = I915_GEM_DOMAIN_CPU;
184	obj->cache_level = HAS_LLC(i915) ? I915_CACHE_LLC : I915_CACHE_NONE;
185
186	return obj;
187}