xref: /openbmc/linux/drivers/gpu/drm/drm_context.c (revision e23feb16)
1 /**
2  * \file drm_context.c
3  * IOCTLs for generic contexts
4  *
5  * \author Rickard E. (Rik) Faith <faith@valinux.com>
6  * \author Gareth Hughes <gareth@valinux.com>
7  */
8 
9 /*
10  * Created: Fri Nov 24 18:31:37 2000 by gareth@valinux.com
11  *
12  * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
13  * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
14  * All Rights Reserved.
15  *
16  * Permission is hereby granted, free of charge, to any person obtaining a
17  * copy of this software and associated documentation files (the "Software"),
18  * to deal in the Software without restriction, including without limitation
19  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
20  * and/or sell copies of the Software, and to permit persons to whom the
21  * Software is furnished to do so, subject to the following conditions:
22  *
23  * The above copyright notice and this permission notice (including the next
24  * paragraph) shall be included in all copies or substantial portions of the
25  * Software.
26  *
27  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
28  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
29  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
30  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
31  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
32  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
33  * OTHER DEALINGS IN THE SOFTWARE.
34  */
35 
36 /*
37  * ChangeLog:
38  *  2001-11-16	Torsten Duwe <duwe@caldera.de>
39  *		added context constructor/destructor hooks,
40  *		needed by SiS driver's memory management.
41  */
42 
43 #include <drm/drmP.h>
44 
45 /******************************************************************/
46 /** \name Context bitmap support */
47 /*@{*/
48 
49 /**
50  * Free a handle from the context bitmap.
51  *
52  * \param dev DRM device.
53  * \param ctx_handle context handle.
54  *
55  * Clears the bit specified by \p ctx_handle in drm_device::ctx_bitmap and the entry
56  * in drm_device::ctx_idr, while holding the drm_device::struct_mutex
57  * lock.
58  */
59 void drm_ctxbitmap_free(struct drm_device * dev, int ctx_handle)
60 {
61 	mutex_lock(&dev->struct_mutex);
62 	idr_remove(&dev->ctx_idr, ctx_handle);
63 	mutex_unlock(&dev->struct_mutex);
64 }
65 
66 /**
67  * Context bitmap allocation.
68  *
69  * \param dev DRM device.
70  * \return (non-negative) context handle on success or a negative number on failure.
71  *
72  * Allocate a new idr from drm_device::ctx_idr while holding the
73  * drm_device::struct_mutex lock.
74  */
75 static int drm_ctxbitmap_next(struct drm_device * dev)
76 {
77 	int ret;
78 
79 	mutex_lock(&dev->struct_mutex);
80 	ret = idr_alloc(&dev->ctx_idr, NULL, DRM_RESERVED_CONTEXTS, 0,
81 			GFP_KERNEL);
82 	mutex_unlock(&dev->struct_mutex);
83 	return ret;
84 }
85 
86 /**
87  * Context bitmap initialization.
88  *
89  * \param dev DRM device.
90  *
91  * Initialise the drm_device::ctx_idr
92  */
93 int drm_ctxbitmap_init(struct drm_device * dev)
94 {
95 	idr_init(&dev->ctx_idr);
96 	return 0;
97 }
98 
99 /**
100  * Context bitmap cleanup.
101  *
102  * \param dev DRM device.
103  *
104  * Free all idr members using drm_ctx_sarea_free helper function
105  * while holding the drm_device::struct_mutex lock.
106  */
107 void drm_ctxbitmap_cleanup(struct drm_device * dev)
108 {
109 	mutex_lock(&dev->struct_mutex);
110 	idr_destroy(&dev->ctx_idr);
111 	mutex_unlock(&dev->struct_mutex);
112 }
113 
114 /*@}*/
115 
116 /******************************************************************/
117 /** \name Per Context SAREA Support */
118 /*@{*/
119 
120 /**
121  * Get per-context SAREA.
122  *
123  * \param inode device inode.
124  * \param file_priv DRM file private.
125  * \param cmd command.
126  * \param arg user argument pointing to a drm_ctx_priv_map structure.
127  * \return zero on success or a negative number on failure.
128  *
129  * Gets the map from drm_device::ctx_idr with the handle specified and
130  * returns its handle.
131  */
132 int drm_getsareactx(struct drm_device *dev, void *data,
133 		    struct drm_file *file_priv)
134 {
135 	struct drm_ctx_priv_map *request = data;
136 	struct drm_local_map *map;
137 	struct drm_map_list *_entry;
138 
139 	mutex_lock(&dev->struct_mutex);
140 
141 	map = idr_find(&dev->ctx_idr, request->ctx_id);
142 	if (!map) {
143 		mutex_unlock(&dev->struct_mutex);
144 		return -EINVAL;
145 	}
146 
147 	request->handle = NULL;
148 	list_for_each_entry(_entry, &dev->maplist, head) {
149 		if (_entry->map == map) {
150 			request->handle =
151 			    (void *)(unsigned long)_entry->user_token;
152 			break;
153 		}
154 	}
155 
156 	mutex_unlock(&dev->struct_mutex);
157 
158 	if (request->handle == NULL)
159 		return -EINVAL;
160 
161 	return 0;
162 }
163 
164 /**
165  * Set per-context SAREA.
166  *
167  * \param inode device inode.
168  * \param file_priv DRM file private.
169  * \param cmd command.
170  * \param arg user argument pointing to a drm_ctx_priv_map structure.
171  * \return zero on success or a negative number on failure.
172  *
173  * Searches the mapping specified in \p arg and update the entry in
174  * drm_device::ctx_idr with it.
175  */
176 int drm_setsareactx(struct drm_device *dev, void *data,
177 		    struct drm_file *file_priv)
178 {
179 	struct drm_ctx_priv_map *request = data;
180 	struct drm_local_map *map = NULL;
181 	struct drm_map_list *r_list = NULL;
182 
183 	mutex_lock(&dev->struct_mutex);
184 	list_for_each_entry(r_list, &dev->maplist, head) {
185 		if (r_list->map
186 		    && r_list->user_token == (unsigned long) request->handle)
187 			goto found;
188 	}
189       bad:
190 	mutex_unlock(&dev->struct_mutex);
191 	return -EINVAL;
192 
193       found:
194 	map = r_list->map;
195 	if (!map)
196 		goto bad;
197 
198 	if (IS_ERR(idr_replace(&dev->ctx_idr, map, request->ctx_id)))
199 		goto bad;
200 
201 	mutex_unlock(&dev->struct_mutex);
202 
203 	return 0;
204 }
205 
206 /*@}*/
207 
208 /******************************************************************/
209 /** \name The actual DRM context handling routines */
210 /*@{*/
211 
212 /**
213  * Switch context.
214  *
215  * \param dev DRM device.
216  * \param old old context handle.
217  * \param new new context handle.
218  * \return zero on success or a negative number on failure.
219  *
220  * Attempt to set drm_device::context_flag.
221  */
222 static int drm_context_switch(struct drm_device * dev, int old, int new)
223 {
224 	if (test_and_set_bit(0, &dev->context_flag)) {
225 		DRM_ERROR("Reentering -- FIXME\n");
226 		return -EBUSY;
227 	}
228 
229 	DRM_DEBUG("Context switch from %d to %d\n", old, new);
230 
231 	if (new == dev->last_context) {
232 		clear_bit(0, &dev->context_flag);
233 		return 0;
234 	}
235 
236 	return 0;
237 }
238 
239 /**
240  * Complete context switch.
241  *
242  * \param dev DRM device.
243  * \param new new context handle.
244  * \return zero on success or a negative number on failure.
245  *
246  * Updates drm_device::last_context and drm_device::last_switch. Verifies the
247  * hardware lock is held, clears the drm_device::context_flag and wakes up
248  * drm_device::context_wait.
249  */
250 static int drm_context_switch_complete(struct drm_device *dev,
251 				       struct drm_file *file_priv, int new)
252 {
253 	dev->last_context = new;	/* PRE/POST: This is the _only_ writer. */
254 
255 	if (!_DRM_LOCK_IS_HELD(file_priv->master->lock.hw_lock->lock)) {
256 		DRM_ERROR("Lock isn't held after context switch\n");
257 	}
258 
259 	/* If a context switch is ever initiated
260 	   when the kernel holds the lock, release
261 	   that lock here. */
262 	clear_bit(0, &dev->context_flag);
263 
264 	return 0;
265 }
266 
267 /**
268  * Reserve contexts.
269  *
270  * \param inode device inode.
271  * \param file_priv DRM file private.
272  * \param cmd command.
273  * \param arg user argument pointing to a drm_ctx_res structure.
274  * \return zero on success or a negative number on failure.
275  */
276 int drm_resctx(struct drm_device *dev, void *data,
277 	       struct drm_file *file_priv)
278 {
279 	struct drm_ctx_res *res = data;
280 	struct drm_ctx ctx;
281 	int i;
282 
283 	if (res->count >= DRM_RESERVED_CONTEXTS) {
284 		memset(&ctx, 0, sizeof(ctx));
285 		for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
286 			ctx.handle = i;
287 			if (copy_to_user(&res->contexts[i], &ctx, sizeof(ctx)))
288 				return -EFAULT;
289 		}
290 	}
291 	res->count = DRM_RESERVED_CONTEXTS;
292 
293 	return 0;
294 }
295 
296 /**
297  * Add context.
298  *
299  * \param inode device inode.
300  * \param file_priv DRM file private.
301  * \param cmd command.
302  * \param arg user argument pointing to a drm_ctx structure.
303  * \return zero on success or a negative number on failure.
304  *
305  * Get a new handle for the context and copy to userspace.
306  */
307 int drm_addctx(struct drm_device *dev, void *data,
308 	       struct drm_file *file_priv)
309 {
310 	struct drm_ctx_list *ctx_entry;
311 	struct drm_ctx *ctx = data;
312 
313 	ctx->handle = drm_ctxbitmap_next(dev);
314 	if (ctx->handle == DRM_KERNEL_CONTEXT) {
315 		/* Skip kernel's context and get a new one. */
316 		ctx->handle = drm_ctxbitmap_next(dev);
317 	}
318 	DRM_DEBUG("%d\n", ctx->handle);
319 	if (ctx->handle == -1) {
320 		DRM_DEBUG("Not enough free contexts.\n");
321 		/* Should this return -EBUSY instead? */
322 		return -ENOMEM;
323 	}
324 
325 	ctx_entry = kmalloc(sizeof(*ctx_entry), GFP_KERNEL);
326 	if (!ctx_entry) {
327 		DRM_DEBUG("out of memory\n");
328 		return -ENOMEM;
329 	}
330 
331 	INIT_LIST_HEAD(&ctx_entry->head);
332 	ctx_entry->handle = ctx->handle;
333 	ctx_entry->tag = file_priv;
334 
335 	mutex_lock(&dev->ctxlist_mutex);
336 	list_add(&ctx_entry->head, &dev->ctxlist);
337 	++dev->ctx_count;
338 	mutex_unlock(&dev->ctxlist_mutex);
339 
340 	return 0;
341 }
342 
343 /**
344  * Get context.
345  *
346  * \param inode device inode.
347  * \param file_priv DRM file private.
348  * \param cmd command.
349  * \param arg user argument pointing to a drm_ctx structure.
350  * \return zero on success or a negative number on failure.
351  */
352 int drm_getctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
353 {
354 	struct drm_ctx *ctx = data;
355 
356 	/* This is 0, because we don't handle any context flags */
357 	ctx->flags = 0;
358 
359 	return 0;
360 }
361 
362 /**
363  * Switch context.
364  *
365  * \param inode device inode.
366  * \param file_priv DRM file private.
367  * \param cmd command.
368  * \param arg user argument pointing to a drm_ctx structure.
369  * \return zero on success or a negative number on failure.
370  *
371  * Calls context_switch().
372  */
373 int drm_switchctx(struct drm_device *dev, void *data,
374 		  struct drm_file *file_priv)
375 {
376 	struct drm_ctx *ctx = data;
377 
378 	DRM_DEBUG("%d\n", ctx->handle);
379 	return drm_context_switch(dev, dev->last_context, ctx->handle);
380 }
381 
382 /**
383  * New context.
384  *
385  * \param inode device inode.
386  * \param file_priv DRM file private.
387  * \param cmd command.
388  * \param arg user argument pointing to a drm_ctx structure.
389  * \return zero on success or a negative number on failure.
390  *
391  * Calls context_switch_complete().
392  */
393 int drm_newctx(struct drm_device *dev, void *data,
394 	       struct drm_file *file_priv)
395 {
396 	struct drm_ctx *ctx = data;
397 
398 	DRM_DEBUG("%d\n", ctx->handle);
399 	drm_context_switch_complete(dev, file_priv, ctx->handle);
400 
401 	return 0;
402 }
403 
404 /**
405  * Remove context.
406  *
407  * \param inode device inode.
408  * \param file_priv DRM file private.
409  * \param cmd command.
410  * \param arg user argument pointing to a drm_ctx structure.
411  * \return zero on success or a negative number on failure.
412  *
413  * If not the special kernel context, calls ctxbitmap_free() to free the specified context.
414  */
415 int drm_rmctx(struct drm_device *dev, void *data,
416 	      struct drm_file *file_priv)
417 {
418 	struct drm_ctx *ctx = data;
419 
420 	DRM_DEBUG("%d\n", ctx->handle);
421 	if (ctx->handle != DRM_KERNEL_CONTEXT) {
422 		if (dev->driver->context_dtor)
423 			dev->driver->context_dtor(dev, ctx->handle);
424 		drm_ctxbitmap_free(dev, ctx->handle);
425 	}
426 
427 	mutex_lock(&dev->ctxlist_mutex);
428 	if (!list_empty(&dev->ctxlist)) {
429 		struct drm_ctx_list *pos, *n;
430 
431 		list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
432 			if (pos->handle == ctx->handle) {
433 				list_del(&pos->head);
434 				kfree(pos);
435 				--dev->ctx_count;
436 			}
437 		}
438 	}
439 	mutex_unlock(&dev->ctxlist_mutex);
440 
441 	return 0;
442 }
443 
444 /*@}*/
445