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 
I915_SELFTEST_DECLARE(static bool force_different_devices;)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 
i915_gem_map_dma_buf(struct dma_buf_attachment * attach,enum dma_data_direction dir)28 static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attach,
29 					     enum dma_data_direction dir)
30 {
31 	struct drm_i915_gem_object *obj = dma_buf_to_obj(attach->dmabuf);
32 	struct sg_table *sgt;
33 	struct scatterlist *src, *dst;
34 	int ret, i;
35 
36 	/*
37 	 * Make a copy of the object's sgt, so that we can make an independent
38 	 * mapping
39 	 */
40 	sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
41 	if (!sgt) {
42 		ret = -ENOMEM;
43 		goto err;
44 	}
45 
46 	ret = sg_alloc_table(sgt, obj->mm.pages->orig_nents, GFP_KERNEL);
47 	if (ret)
48 		goto err_free;
49 
50 	dst = sgt->sgl;
51 	for_each_sg(obj->mm.pages->sgl, src, obj->mm.pages->orig_nents, i) {
52 		sg_set_page(dst, sg_page(src), src->length, 0);
53 		dst = sg_next(dst);
54 	}
55 
56 	ret = dma_map_sgtable(attach->dev, sgt, dir, DMA_ATTR_SKIP_CPU_SYNC);
57 	if (ret)
58 		goto err_free_sg;
59 
60 	return sgt;
61 
62 err_free_sg:
63 	sg_free_table(sgt);
64 err_free:
65 	kfree(sgt);
66 err:
67 	return ERR_PTR(ret);
68 }
69 
i915_gem_dmabuf_vmap(struct dma_buf * dma_buf,struct iosys_map * map)70 static int i915_gem_dmabuf_vmap(struct dma_buf *dma_buf,
71 				struct iosys_map *map)
72 {
73 	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
74 	void *vaddr;
75 
76 	vaddr = i915_gem_object_pin_map(obj, I915_MAP_WB);
77 	if (IS_ERR(vaddr))
78 		return PTR_ERR(vaddr);
79 
80 	iosys_map_set_vaddr(map, vaddr);
81 
82 	return 0;
83 }
84 
i915_gem_dmabuf_vunmap(struct dma_buf * dma_buf,struct iosys_map * map)85 static void i915_gem_dmabuf_vunmap(struct dma_buf *dma_buf,
86 				   struct iosys_map *map)
87 {
88 	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
89 
90 	i915_gem_object_flush_map(obj);
91 	i915_gem_object_unpin_map(obj);
92 }
93 
i915_gem_dmabuf_mmap(struct dma_buf * dma_buf,struct vm_area_struct * vma)94 static int i915_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
95 {
96 	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
97 	struct drm_i915_private *i915 = to_i915(obj->base.dev);
98 	int ret;
99 
100 	if (obj->base.size < vma->vm_end - vma->vm_start)
101 		return -EINVAL;
102 
103 	if (HAS_LMEM(i915))
104 		return drm_gem_prime_mmap(&obj->base, vma);
105 
106 	if (!obj->base.filp)
107 		return -ENODEV;
108 
109 	ret = call_mmap(obj->base.filp, vma);
110 	if (ret)
111 		return ret;
112 
113 	vma_set_file(vma, obj->base.filp);
114 
115 	return 0;
116 }
117 
i915_gem_begin_cpu_access(struct dma_buf * dma_buf,enum dma_data_direction direction)118 static int i915_gem_begin_cpu_access(struct dma_buf *dma_buf, enum dma_data_direction direction)
119 {
120 	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
121 	bool write = (direction == DMA_BIDIRECTIONAL || direction == DMA_TO_DEVICE);
122 	struct i915_gem_ww_ctx ww;
123 	int err;
124 
125 	i915_gem_ww_ctx_init(&ww, true);
126 retry:
127 	err = i915_gem_object_lock(obj, &ww);
128 	if (!err)
129 		err = i915_gem_object_pin_pages(obj);
130 	if (!err) {
131 		err = i915_gem_object_set_to_cpu_domain(obj, write);
132 		i915_gem_object_unpin_pages(obj);
133 	}
134 	if (err == -EDEADLK) {
135 		err = i915_gem_ww_ctx_backoff(&ww);
136 		if (!err)
137 			goto retry;
138 	}
139 	i915_gem_ww_ctx_fini(&ww);
140 	return err;
141 }
142 
i915_gem_end_cpu_access(struct dma_buf * dma_buf,enum dma_data_direction direction)143 static int i915_gem_end_cpu_access(struct dma_buf *dma_buf, enum dma_data_direction direction)
144 {
145 	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
146 	struct i915_gem_ww_ctx ww;
147 	int err;
148 
149 	i915_gem_ww_ctx_init(&ww, true);
150 retry:
151 	err = i915_gem_object_lock(obj, &ww);
152 	if (!err)
153 		err = i915_gem_object_pin_pages(obj);
154 	if (!err) {
155 		err = i915_gem_object_set_to_gtt_domain(obj, false);
156 		i915_gem_object_unpin_pages(obj);
157 	}
158 	if (err == -EDEADLK) {
159 		err = i915_gem_ww_ctx_backoff(&ww);
160 		if (!err)
161 			goto retry;
162 	}
163 	i915_gem_ww_ctx_fini(&ww);
164 	return err;
165 }
166 
i915_gem_dmabuf_attach(struct dma_buf * dmabuf,struct dma_buf_attachment * attach)167 static int i915_gem_dmabuf_attach(struct dma_buf *dmabuf,
168 				  struct dma_buf_attachment *attach)
169 {
170 	struct drm_i915_gem_object *obj = dma_buf_to_obj(dmabuf);
171 	struct i915_gem_ww_ctx ww;
172 	int err;
173 
174 	if (!i915_gem_object_can_migrate(obj, INTEL_REGION_SMEM))
175 		return -EOPNOTSUPP;
176 
177 	for_i915_gem_ww(&ww, err, true) {
178 		err = i915_gem_object_lock(obj, &ww);
179 		if (err)
180 			continue;
181 
182 		err = i915_gem_object_migrate(obj, &ww, INTEL_REGION_SMEM);
183 		if (err)
184 			continue;
185 
186 		err = i915_gem_object_wait_migration(obj, 0);
187 		if (err)
188 			continue;
189 
190 		err = i915_gem_object_pin_pages(obj);
191 	}
192 
193 	return err;
194 }
195 
i915_gem_dmabuf_detach(struct dma_buf * dmabuf,struct dma_buf_attachment * attach)196 static void i915_gem_dmabuf_detach(struct dma_buf *dmabuf,
197 				   struct dma_buf_attachment *attach)
198 {
199 	struct drm_i915_gem_object *obj = dma_buf_to_obj(dmabuf);
200 
201 	i915_gem_object_unpin_pages(obj);
202 }
203 
204 static const struct dma_buf_ops i915_dmabuf_ops =  {
205 	.attach = i915_gem_dmabuf_attach,
206 	.detach = i915_gem_dmabuf_detach,
207 	.map_dma_buf = i915_gem_map_dma_buf,
208 	.unmap_dma_buf = drm_gem_unmap_dma_buf,
209 	.release = drm_gem_dmabuf_release,
210 	.mmap = i915_gem_dmabuf_mmap,
211 	.vmap = i915_gem_dmabuf_vmap,
212 	.vunmap = i915_gem_dmabuf_vunmap,
213 	.begin_cpu_access = i915_gem_begin_cpu_access,
214 	.end_cpu_access = i915_gem_end_cpu_access,
215 };
216 
i915_gem_prime_export(struct drm_gem_object * gem_obj,int flags)217 struct dma_buf *i915_gem_prime_export(struct drm_gem_object *gem_obj, int flags)
218 {
219 	struct drm_i915_gem_object *obj = to_intel_bo(gem_obj);
220 	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
221 
222 	exp_info.ops = &i915_dmabuf_ops;
223 	exp_info.size = gem_obj->size;
224 	exp_info.flags = flags;
225 	exp_info.priv = gem_obj;
226 	exp_info.resv = obj->base.resv;
227 
228 	if (obj->ops->dmabuf_export) {
229 		int ret = obj->ops->dmabuf_export(obj);
230 		if (ret)
231 			return ERR_PTR(ret);
232 	}
233 
234 	return drm_gem_dmabuf_export(gem_obj->dev, &exp_info);
235 }
236 
i915_gem_object_get_pages_dmabuf(struct drm_i915_gem_object * obj)237 static int i915_gem_object_get_pages_dmabuf(struct drm_i915_gem_object *obj)
238 {
239 	struct drm_i915_private *i915 = to_i915(obj->base.dev);
240 	struct sg_table *sgt;
241 
242 	assert_object_held(obj);
243 
244 	sgt = dma_buf_map_attachment(obj->base.import_attach,
245 				     DMA_BIDIRECTIONAL);
246 	if (IS_ERR(sgt))
247 		return PTR_ERR(sgt);
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 	__i915_gem_object_set_pages(obj, sgt);
265 
266 	return 0;
267 }
268 
i915_gem_object_put_pages_dmabuf(struct drm_i915_gem_object * obj,struct sg_table * sgt)269 static void i915_gem_object_put_pages_dmabuf(struct drm_i915_gem_object *obj,
270 					     struct sg_table *sgt)
271 {
272 	dma_buf_unmap_attachment(obj->base.import_attach, sgt,
273 				 DMA_BIDIRECTIONAL);
274 }
275 
276 static const struct drm_i915_gem_object_ops i915_gem_object_dmabuf_ops = {
277 	.name = "i915_gem_object_dmabuf",
278 	.get_pages = i915_gem_object_get_pages_dmabuf,
279 	.put_pages = i915_gem_object_put_pages_dmabuf,
280 };
281 
i915_gem_prime_import(struct drm_device * dev,struct dma_buf * dma_buf)282 struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev,
283 					     struct dma_buf *dma_buf)
284 {
285 	static struct lock_class_key lock_class;
286 	struct dma_buf_attachment *attach;
287 	struct drm_i915_gem_object *obj;
288 	int ret;
289 
290 	/* is this one of own objects? */
291 	if (dma_buf->ops == &i915_dmabuf_ops) {
292 		obj = dma_buf_to_obj(dma_buf);
293 		/* is it from our device? */
294 		if (obj->base.dev == dev &&
295 		    !I915_SELFTEST_ONLY(force_different_devices)) {
296 			/*
297 			 * Importing dmabuf exported from out own gem increases
298 			 * refcount on gem itself instead of f_count of dmabuf.
299 			 */
300 			return &i915_gem_object_get(obj)->base;
301 		}
302 	}
303 
304 	if (i915_gem_object_size_2big(dma_buf->size))
305 		return ERR_PTR(-E2BIG);
306 
307 	/* need to attach */
308 	attach = dma_buf_attach(dma_buf, dev->dev);
309 	if (IS_ERR(attach))
310 		return ERR_CAST(attach);
311 
312 	get_dma_buf(dma_buf);
313 
314 	obj = i915_gem_object_alloc();
315 	if (!obj) {
316 		ret = -ENOMEM;
317 		goto fail_detach;
318 	}
319 
320 	drm_gem_private_object_init(dev, &obj->base, dma_buf->size);
321 	i915_gem_object_init(obj, &i915_gem_object_dmabuf_ops, &lock_class,
322 			     I915_BO_ALLOC_USER);
323 	obj->base.import_attach = attach;
324 	obj->base.resv = dma_buf->resv;
325 
326 	/* We use GTT as shorthand for a coherent domain, one that is
327 	 * neither in the GPU cache nor in the CPU cache, where all
328 	 * writes are immediately visible in memory. (That's not strictly
329 	 * true, but it's close! There are internal buffers such as the
330 	 * write-combined buffer or a delay through the chipset for GTT
331 	 * writes that do require us to treat GTT as a separate cache domain.)
332 	 */
333 	obj->read_domains = I915_GEM_DOMAIN_GTT;
334 	obj->write_domain = 0;
335 
336 	return &obj->base;
337 
338 fail_detach:
339 	dma_buf_detach(dma_buf, attach);
340 	dma_buf_put(dma_buf);
341 
342 	return ERR_PTR(ret);
343 }
344 
345 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
346 #include "selftests/mock_dmabuf.c"
347 #include "selftests/i915_gem_dmabuf.c"
348 #endif
349