Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
drm/panthor: Provide a custom dma_buf implementation
Before we introduce cached CPU mappings, we want a dma_buf
implementation satisfying synchronization requests around CPU
accesses coming from a dma_buf exported by our driver. Let's
provide our own implementation relying on the default
gem_shmem_prime helpers designed for that purpose.
v5:
- New patch
v6:
- Collect R-b
v7:
- Hand-roll the dma_buf sync/import logic (was previously done by
generic prime/shmem helpers)
v8:
- No changes
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://patch.msgid.link/20251208100841.730527-2-boris.brezillon@collabora.com
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
+122
-1
+1
drivers/gpu/drm/panthor/panthor_drv.c
+1
drivers/gpu/drm/panthor/panthor_drv.c
+117
-1
drivers/gpu/drm/panthor/panthor_gem.c
+117
-1
drivers/gpu/drm/panthor/panthor_gem.c
···
202
202
return ERR_PTR(ret);
203
203
}
204
204
205
+
static struct sg_table *
206
+
panthor_gem_prime_map_dma_buf(struct dma_buf_attachment *attach,
207
+
enum dma_data_direction dir)
208
+
{
209
+
struct sg_table *sgt = drm_gem_map_dma_buf(attach, dir);
210
+
211
+
if (!IS_ERR(sgt))
212
+
attach->priv = sgt;
213
+
214
+
return sgt;
215
+
}
216
+
217
+
static void
218
+
panthor_gem_prime_unmap_dma_buf(struct dma_buf_attachment *attach,
219
+
struct sg_table *sgt,
220
+
enum dma_data_direction dir)
221
+
{
222
+
attach->priv = NULL;
223
+
drm_gem_unmap_dma_buf(attach, sgt, dir);
224
+
}
225
+
226
+
static int
227
+
panthor_gem_prime_begin_cpu_access(struct dma_buf *dma_buf,
228
+
enum dma_data_direction dir)
229
+
{
230
+
struct drm_gem_object *obj = dma_buf->priv;
231
+
struct drm_device *dev = obj->dev;
232
+
struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
233
+
struct dma_buf_attachment *attach;
234
+
235
+
dma_resv_lock(obj->resv, NULL);
236
+
if (shmem->sgt)
237
+
dma_sync_sgtable_for_cpu(dev->dev, shmem->sgt, dir);
238
+
239
+
if (shmem->vaddr)
240
+
invalidate_kernel_vmap_range(shmem->vaddr, shmem->base.size);
241
+
242
+
list_for_each_entry(attach, &dma_buf->attachments, node) {
243
+
struct sg_table *sgt = attach->priv;
244
+
245
+
if (sgt)
246
+
dma_sync_sgtable_for_cpu(attach->dev, sgt, dir);
247
+
}
248
+
dma_resv_unlock(obj->resv);
249
+
250
+
return 0;
251
+
}
252
+
253
+
static int
254
+
panthor_gem_prime_end_cpu_access(struct dma_buf *dma_buf,
255
+
enum dma_data_direction dir)
256
+
{
257
+
struct drm_gem_object *obj = dma_buf->priv;
258
+
struct drm_device *dev = obj->dev;
259
+
struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
260
+
struct dma_buf_attachment *attach;
261
+
262
+
dma_resv_lock(obj->resv, NULL);
263
+
list_for_each_entry(attach, &dma_buf->attachments, node) {
264
+
struct sg_table *sgt = attach->priv;
265
+
266
+
if (sgt)
267
+
dma_sync_sgtable_for_device(attach->dev, sgt, dir);
268
+
}
269
+
270
+
if (shmem->vaddr)
271
+
flush_kernel_vmap_range(shmem->vaddr, shmem->base.size);
272
+
273
+
if (shmem->sgt)
274
+
dma_sync_sgtable_for_device(dev->dev, shmem->sgt, dir);
275
+
276
+
dma_resv_unlock(obj->resv);
277
+
return 0;
278
+
}
279
+
280
+
static const struct dma_buf_ops panthor_dma_buf_ops = {
281
+
.attach = drm_gem_map_attach,
282
+
.detach = drm_gem_map_detach,
283
+
.map_dma_buf = panthor_gem_prime_map_dma_buf,
284
+
.unmap_dma_buf = panthor_gem_prime_unmap_dma_buf,
285
+
.release = drm_gem_dmabuf_release,
286
+
.mmap = drm_gem_dmabuf_mmap,
287
+
.vmap = drm_gem_dmabuf_vmap,
288
+
.vunmap = drm_gem_dmabuf_vunmap,
289
+
.begin_cpu_access = panthor_gem_prime_begin_cpu_access,
290
+
.end_cpu_access = panthor_gem_prime_end_cpu_access,
291
+
};
292
+
205
293
static struct dma_buf *
206
294
panthor_gem_prime_export(struct drm_gem_object *obj, int flags)
207
295
{
296
+
struct drm_device *dev = obj->dev;
297
+
struct dma_buf_export_info exp_info = {
298
+
.exp_name = KBUILD_MODNAME,
299
+
.owner = THIS_MODULE,
300
+
.ops = &panthor_dma_buf_ops,
301
+
.size = obj->size,
302
+
.flags = flags,
303
+
.priv = obj,
304
+
.resv = obj->resv,
305
+
};
306
+
208
307
/* We can't export GEMs that have an exclusive VM. */
209
308
if (to_panthor_bo(obj)->exclusive_vm_root_gem)
210
309
return ERR_PTR(-EINVAL);
211
310
212
-
return drm_gem_prime_export(obj, flags);
311
+
return drm_gem_dmabuf_export(dev, &exp_info);
312
+
}
313
+
314
+
struct drm_gem_object *
315
+
panthor_gem_prime_import(struct drm_device *dev,
316
+
struct dma_buf *dma_buf)
317
+
{
318
+
struct drm_gem_object *obj = dma_buf->priv;
319
+
320
+
if (dma_buf->ops == &panthor_dma_buf_ops && obj->dev == dev) {
321
+
/* Importing dmabuf exported from our own gem increases
322
+
* refcount on gem itself instead of f_count of dmabuf.
323
+
*/
324
+
drm_gem_object_get(obj);
325
+
return obj;
326
+
}
327
+
328
+
return drm_gem_prime_import(dev, dma_buf);
213
329
}
214
330
215
331
static enum drm_gem_object_status panthor_gem_status(struct drm_gem_object *obj)
+4
drivers/gpu/drm/panthor/panthor_gem.h
+4
drivers/gpu/drm/panthor/panthor_gem.h
···
149
149
void panthor_gem_bo_set_label(struct drm_gem_object *obj, const char *label);
150
150
void panthor_gem_kernel_bo_set_label(struct panthor_kernel_bo *bo, const char *label);
151
151
152
+
struct drm_gem_object *
153
+
panthor_gem_prime_import(struct drm_device *dev,
154
+
struct dma_buf *dma_buf);
155
+
152
156
static inline u64
153
157
panthor_kernel_bo_gpuva(struct panthor_kernel_bo *bo)
154
158
{