1 /*
2  * SPDX-License-Identifier: MIT
3  *
4  * Copyright 2012 Red Hat Inc
5  */
6 
7 #include <linux/dma-buf.h>
8 #include <linux/highmem.h>
9 #include <linux/dma-resv.h>
10 #include <linux/module.h>
11 
12 #include <asm/smp.h>
13 
14 #include "gem/i915_gem_dmabuf.h"
15 #include "i915_drv.h"
16 #include "i915_gem_object.h"
17 #include "i915_scatterlist.h"
18 
19 MODULE_IMPORT_NS(DMA_BUF);
20 
21 I915_SELFTEST_DECLARE(static bool force_different_devices;)
22 
23 static struct drm_i915_gem_object *dma_buf_to_obj(struct dma_buf *buf)
24 {
25 	return to_intel_bo(buf->priv);
26 }
27 
28 static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachment,
29 					     enum dma_data_direction dir)
30 {
31 	struct drm_i915_gem_object *obj = dma_buf_to_obj(attachment->dmabuf);
32 	struct sg_table *st;
33 	struct scatterlist *src, *dst;
34 	int ret, i;
35 
36 	/* Copy sg so that we make an independent mapping */
37 	st = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
38 	if (st == NULL) {
39 		ret = -ENOMEM;
40 		goto err;
41 	}
42 
43 	ret = sg_alloc_table(st, obj->mm.pages->nents, GFP_KERNEL);
44 	if (ret)
45 		goto err_free;
46 
47 	src = obj->mm.pages->sgl;
48 	dst = st->sgl;
49 	for (i = 0; i < obj->mm.pages->nents; i++) {
50 		sg_set_page(dst, sg_page(src), src->length, 0);
51 		dst = sg_next(dst);
52 		src = sg_next(src);
53 	}
54 
55 	ret = dma_map_sgtable(attachment->dev, st, dir, DMA_ATTR_SKIP_CPU_SYNC);
56 	if (ret)
57 		goto err_free_sg;
58 
59 	return st;
60 
61 err_free_sg:
62 	sg_free_table(st);
63 err_free:
64 	kfree(st);
65 err:
66 	return ERR_PTR(ret);
67 }
68 
69 static int i915_gem_dmabuf_vmap(struct dma_buf *dma_buf,
70 				struct iosys_map *map)
71 {
72 	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
73 	void *vaddr;
74 
75 	vaddr = i915_gem_object_pin_map_unlocked(obj, I915_MAP_WB);
76 	if (IS_ERR(vaddr))
77 		return PTR_ERR(vaddr);
78 
79 	iosys_map_set_vaddr(map, vaddr);
80 
81 	return 0;
82 }
83 
84 static void i915_gem_dmabuf_vunmap(struct dma_buf *dma_buf,
85 				   struct iosys_map *map)
86 {
87 	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
88 
89 	i915_gem_object_flush_map(obj);
90 	i915_gem_object_unpin_map(obj);
91 }
92 
93 static int i915_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
94 {
95 	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
96 	struct drm_i915_private *i915 = to_i915(obj->base.dev);
97 	int ret;
98 
99 	if (obj->base.size < vma->vm_end - vma->vm_start)
100 		return -EINVAL;
101 
102 	if (HAS_LMEM(i915))
103 		return drm_gem_prime_mmap(&obj->base, vma);
104 
105 	if (!obj->base.filp)
106 		return -ENODEV;
107 
108 	ret = call_mmap(obj->base.filp, vma);
109 	if (ret)
110 		return ret;
111 
112 	vma_set_file(vma, obj->base.filp);
113 
114 	return 0;
115 }
116 
117 static int i915_gem_begin_cpu_access(struct dma_buf *dma_buf, enum dma_data_direction direction)
118 {
119 	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
120 	bool write = (direction == DMA_BIDIRECTIONAL || direction == DMA_TO_DEVICE);
121 	struct i915_gem_ww_ctx ww;
122 	int err;
123 
124 	i915_gem_ww_ctx_init(&ww, true);
125 retry:
126 	err = i915_gem_object_lock(obj, &ww);
127 	if (!err)
128 		err = i915_gem_object_pin_pages(obj);
129 	if (!err) {
130 		err = i915_gem_object_set_to_cpu_domain(obj, write);
131 		i915_gem_object_unpin_pages(obj);
132 	}
133 	if (err == -EDEADLK) {
134 		err = i915_gem_ww_ctx_backoff(&ww);
135 		if (!err)
136 			goto retry;
137 	}
138 	i915_gem_ww_ctx_fini(&ww);
139 	return err;
140 }
141 
142 static int i915_gem_end_cpu_access(struct dma_buf *dma_buf, enum dma_data_direction direction)
143 {
144 	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
145 	struct i915_gem_ww_ctx ww;
146 	int err;
147 
148 	i915_gem_ww_ctx_init(&ww, true);
149 retry:
150 	err = i915_gem_object_lock(obj, &ww);
151 	if (!err)
152 		err = i915_gem_object_pin_pages(obj);
153 	if (!err) {
154 		err = i915_gem_object_set_to_gtt_domain(obj, false);
155 		i915_gem_object_unpin_pages(obj);
156 	}
157 	if (err == -EDEADLK) {
158 		err = i915_gem_ww_ctx_backoff(&ww);
159 		if (!err)
160 			goto retry;
161 	}
162 	i915_gem_ww_ctx_fini(&ww);
163 	return err;
164 }
165 
166 static int i915_gem_dmabuf_attach(struct dma_buf *dmabuf,
167 				  struct dma_buf_attachment *attach)
168 {
169 	struct drm_i915_gem_object *obj = dma_buf_to_obj(dmabuf);
170 	struct i915_gem_ww_ctx ww;
171 	int err;
172 
173 	if (!i915_gem_object_can_migrate(obj, INTEL_REGION_SMEM))
174 		return -EOPNOTSUPP;
175 
176 	for_i915_gem_ww(&ww, err, true) {
177 		err = i915_gem_object_lock(obj, &ww);
178 		if (err)
179 			continue;
180 
181 		err = i915_gem_object_migrate(obj, &ww, INTEL_REGION_SMEM);
182 		if (err)
183 			continue;
184 
185 		err = i915_gem_object_wait_migration(obj, 0);
186 		if (err)
187 			continue;
188 
189 		err = i915_gem_object_pin_pages(obj);
190 	}
191 
192 	return err;
193 }
194 
195 static void i915_gem_dmabuf_detach(struct dma_buf *dmabuf,
196 				   struct dma_buf_attachment *attach)
197 {
198 	struct drm_i915_gem_object *obj = dma_buf_to_obj(dmabuf);
199 
200 	i915_gem_object_unpin_pages(obj);
201 }
202 
203 static const struct dma_buf_ops i915_dmabuf_ops =  {
204 	.attach = i915_gem_dmabuf_attach,
205 	.detach = i915_gem_dmabuf_detach,
206 	.map_dma_buf = i915_gem_map_dma_buf,
207 	.unmap_dma_buf = drm_gem_unmap_dma_buf,
208 	.release = drm_gem_dmabuf_release,
209 	.mmap = i915_gem_dmabuf_mmap,
210 	.vmap = i915_gem_dmabuf_vmap,
211 	.vunmap = i915_gem_dmabuf_vunmap,
212 	.begin_cpu_access = i915_gem_begin_cpu_access,
213 	.end_cpu_access = i915_gem_end_cpu_access,
214 };
215 
216 struct dma_buf *i915_gem_prime_export(struct drm_gem_object *gem_obj, int flags)
217 {
218 	struct drm_i915_gem_object *obj = to_intel_bo(gem_obj);
219 	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
220 
221 	exp_info.ops = &i915_dmabuf_ops;
222 	exp_info.size = gem_obj->size;
223 	exp_info.flags = flags;
224 	exp_info.priv = gem_obj;
225 	exp_info.resv = obj->base.resv;
226 
227 	if (obj->ops->dmabuf_export) {
228 		int ret = obj->ops->dmabuf_export(obj);
229 		if (ret)
230 			return ERR_PTR(ret);
231 	}
232 
233 	return drm_gem_dmabuf_export(gem_obj->dev, &exp_info);
234 }
235 
236 static int i915_gem_object_get_pages_dmabuf(struct drm_i915_gem_object *obj)
237 {
238 	struct drm_i915_private *i915 = to_i915(obj->base.dev);
239 	struct sg_table *pages;
240 	unsigned int sg_page_sizes;
241 
242 	assert_object_held(obj);
243 
244 	pages = dma_buf_map_attachment(obj->base.import_attach,
245 				       DMA_BIDIRECTIONAL);
246 	if (IS_ERR(pages))
247 		return PTR_ERR(pages);
248 
249 	/*
250 	 * DG1 is special here since it still snoops transactions even with
251 	 * CACHE_NONE. This is not the case with other HAS_SNOOP platforms. We
252 	 * might need to revisit this as we add new discrete platforms.
253 	 *
254 	 * XXX: Consider doing a vmap flush or something, where possible.
255 	 * Currently we just do a heavy handed wbinvd_on_all_cpus() here since
256 	 * the underlying sg_table might not even point to struct pages, so we
257 	 * can't just call drm_clflush_sg or similar, like we do elsewhere in
258 	 * the driver.
259 	 */
260 	if (i915_gem_object_can_bypass_llc(obj) ||
261 	    (!HAS_LLC(i915) && !IS_DG1(i915)))
262 		wbinvd_on_all_cpus();
263 
264 	sg_page_sizes = i915_sg_dma_sizes(pages->sgl);
265 	__i915_gem_object_set_pages(obj, pages, sg_page_sizes);
266 
267 	return 0;
268 }
269 
270 static void i915_gem_object_put_pages_dmabuf(struct drm_i915_gem_object *obj,
271 					     struct sg_table *pages)
272 {
273 	dma_buf_unmap_attachment(obj->base.import_attach, pages,
274 				 DMA_BIDIRECTIONAL);
275 }
276 
277 static const struct drm_i915_gem_object_ops i915_gem_object_dmabuf_ops = {
278 	.name = "i915_gem_object_dmabuf",
279 	.get_pages = i915_gem_object_get_pages_dmabuf,
280 	.put_pages = i915_gem_object_put_pages_dmabuf,
281 };
282 
283 struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev,
284 					     struct dma_buf *dma_buf)
285 {
286 	static struct lock_class_key lock_class;
287 	struct dma_buf_attachment *attach;
288 	struct drm_i915_gem_object *obj;
289 	int ret;
290 
291 	/* is this one of own objects? */
292 	if (dma_buf->ops == &i915_dmabuf_ops) {
293 		obj = dma_buf_to_obj(dma_buf);
294 		/* is it from our device? */
295 		if (obj->base.dev == dev &&
296 		    !I915_SELFTEST_ONLY(force_different_devices)) {
297 			/*
298 			 * Importing dmabuf exported from out own gem increases
299 			 * refcount on gem itself instead of f_count of dmabuf.
300 			 */
301 			return &i915_gem_object_get(obj)->base;
302 		}
303 	}
304 
305 	if (i915_gem_object_size_2big(dma_buf->size))
306 		return ERR_PTR(-E2BIG);
307 
308 	/* need to attach */
309 	attach = dma_buf_attach(dma_buf, dev->dev);
310 	if (IS_ERR(attach))
311 		return ERR_CAST(attach);
312 
313 	get_dma_buf(dma_buf);
314 
315 	obj = i915_gem_object_alloc();
316 	if (obj == NULL) {
317 		ret = -ENOMEM;
318 		goto fail_detach;
319 	}
320 
321 	drm_gem_private_object_init(dev, &obj->base, dma_buf->size);
322 	i915_gem_object_init(obj, &i915_gem_object_dmabuf_ops, &lock_class,
323 			     I915_BO_ALLOC_USER);
324 	obj->base.import_attach = attach;
325 	obj->base.resv = dma_buf->resv;
326 
327 	/* We use GTT as shorthand for a coherent domain, one that is
328 	 * neither in the GPU cache nor in the CPU cache, where all
329 	 * writes are immediately visible in memory. (That's not strictly
330 	 * true, but it's close! There are internal buffers such as the
331 	 * write-combined buffer or a delay through the chipset for GTT
332 	 * writes that do require us to treat GTT as a separate cache domain.)
333 	 */
334 	obj->read_domains = I915_GEM_DOMAIN_GTT;
335 	obj->write_domain = 0;
336 
337 	return &obj->base;
338 
339 fail_detach:
340 	dma_buf_detach(dma_buf, attach);
341 	dma_buf_put(dma_buf);
342 
343 	return ERR_PTR(ret);
344 }
345 
346 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
347 #include "selftests/mock_dmabuf.c"
348 #include "selftests/i915_gem_dmabuf.c"
349 #endif
350