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 "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 */
59void 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 */
75static int drm_ctxbitmap_next(struct drm_device * dev)
76{
77	int new_id;
78	int ret;
79
80again:
81	if (idr_pre_get(&dev->ctx_idr, GFP_KERNEL) == 0) {
82		DRM_ERROR("Out of memory expanding drawable idr\n");
83		return -ENOMEM;
84	}
85	mutex_lock(&dev->struct_mutex);
86	ret = idr_get_new_above(&dev->ctx_idr, NULL,
87				DRM_RESERVED_CONTEXTS, &new_id);
88	if (ret == -EAGAIN) {
89		mutex_unlock(&dev->struct_mutex);
90		goto again;
91	}
92	mutex_unlock(&dev->struct_mutex);
93	return new_id;
94}
95
96/**
97 * Context bitmap initialization.
98 *
99 * \param dev DRM device.
100 *
101 * Initialise the drm_device::ctx_idr
102 */
103int drm_ctxbitmap_init(struct drm_device * dev)
104{
105	idr_init(&dev->ctx_idr);
106	return 0;
107}
108
109/**
110 * Context bitmap cleanup.
111 *
112 * \param dev DRM device.
113 *
114 * Free all idr members using drm_ctx_sarea_free helper function
115 * while holding the drm_device::struct_mutex lock.
116 */
117void drm_ctxbitmap_cleanup(struct drm_device * dev)
118{
119	mutex_lock(&dev->struct_mutex);
120	idr_remove_all(&dev->ctx_idr);
121	mutex_unlock(&dev->struct_mutex);
122}
123
124/*@}*/
125
126/******************************************************************/
127/** \name Per Context SAREA Support */
128/*@{*/
129
130/**
131 * Get per-context SAREA.
132 *
133 * \param inode device inode.
134 * \param file_priv DRM file private.
135 * \param cmd command.
136 * \param arg user argument pointing to a drm_ctx_priv_map structure.
137 * \return zero on success or a negative number on failure.
138 *
139 * Gets the map from drm_device::ctx_idr with the handle specified and
140 * returns its handle.
141 */
142int drm_getsareactx(struct drm_device *dev, void *data,
143		    struct drm_file *file_priv)
144{
145	struct drm_ctx_priv_map *request = data;
146	struct drm_local_map *map;
147	struct drm_map_list *_entry;
148
149	mutex_lock(&dev->struct_mutex);
150
151	map = idr_find(&dev->ctx_idr, request->ctx_id);
152	if (!map) {
153		mutex_unlock(&dev->struct_mutex);
154		return -EINVAL;
155	}
156
157	request->handle = NULL;
158	list_for_each_entry(_entry, &dev->maplist, head) {
159		if (_entry->map == map) {
160			request->handle =
161			    (void *)(unsigned long)_entry->user_token;
162			break;
163		}
164	}
165
166	mutex_unlock(&dev->struct_mutex);
167
168	if (request->handle == NULL)
169		return -EINVAL;
170
171	return 0;
172}
173
174/**
175 * Set per-context SAREA.
176 *
177 * \param inode device inode.
178 * \param file_priv DRM file private.
179 * \param cmd command.
180 * \param arg user argument pointing to a drm_ctx_priv_map structure.
181 * \return zero on success or a negative number on failure.
182 *
183 * Searches the mapping specified in \p arg and update the entry in
184 * drm_device::ctx_idr with it.
185 */
186int drm_setsareactx(struct drm_device *dev, void *data,
187		    struct drm_file *file_priv)
188{
189	struct drm_ctx_priv_map *request = data;
190	struct drm_local_map *map = NULL;
191	struct drm_map_list *r_list = NULL;
192
193	mutex_lock(&dev->struct_mutex);
194	list_for_each_entry(r_list, &dev->maplist, head) {
195		if (r_list->map
196		    && r_list->user_token == (unsigned long) request->handle)
197			goto found;
198	}
199      bad:
200	mutex_unlock(&dev->struct_mutex);
201	return -EINVAL;
202
203      found:
204	map = r_list->map;
205	if (!map)
206		goto bad;
207
208	if (IS_ERR(idr_replace(&dev->ctx_idr, map, request->ctx_id)))
209		goto bad;
210
211	mutex_unlock(&dev->struct_mutex);
212
213	return 0;
214}
215
216/*@}*/
217
218/******************************************************************/
219/** \name The actual DRM context handling routines */
220/*@{*/
221
222/**
223 * Switch context.
224 *
225 * \param dev DRM device.
226 * \param old old context handle.
227 * \param new new context handle.
228 * \return zero on success or a negative number on failure.
229 *
230 * Attempt to set drm_device::context_flag.
231 */
232static int drm_context_switch(struct drm_device * dev, int old, int new)
233{
234	if (test_and_set_bit(0, &dev->context_flag)) {
235		DRM_ERROR("Reentering -- FIXME\n");
236		return -EBUSY;
237	}
238
239	DRM_DEBUG("Context switch from %d to %d\n", old, new);
240
241	if (new == dev->last_context) {
242		clear_bit(0, &dev->context_flag);
243		return 0;
244	}
245
246	return 0;
247}
248
249/**
250 * Complete context switch.
251 *
252 * \param dev DRM device.
253 * \param new new context handle.
254 * \return zero on success or a negative number on failure.
255 *
256 * Updates drm_device::last_context and drm_device::last_switch. Verifies the
257 * hardware lock is held, clears the drm_device::context_flag and wakes up
258 * drm_device::context_wait.
259 */
260static int drm_context_switch_complete(struct drm_device *dev,
261				       struct drm_file *file_priv, int new)
262{
263	dev->last_context = new;	/* PRE/POST: This is the _only_ writer. */
264	dev->last_switch = jiffies;
265
266	if (!_DRM_LOCK_IS_HELD(file_priv->master->lock.hw_lock->lock)) {
267		DRM_ERROR("Lock isn't held after context switch\n");
268	}
269
270	/* If a context switch is ever initiated
271	   when the kernel holds the lock, release
272	   that lock here. */
273	clear_bit(0, &dev->context_flag);
274	wake_up(&dev->context_wait);
275
276	return 0;
277}
278
279/**
280 * Reserve contexts.
281 *
282 * \param inode device inode.
283 * \param file_priv DRM file private.
284 * \param cmd command.
285 * \param arg user argument pointing to a drm_ctx_res structure.
286 * \return zero on success or a negative number on failure.
287 */
288int drm_resctx(struct drm_device *dev, void *data,
289	       struct drm_file *file_priv)
290{
291	struct drm_ctx_res *res = data;
292	struct drm_ctx ctx;
293	int i;
294
295	if (res->count >= DRM_RESERVED_CONTEXTS) {
296		memset(&ctx, 0, sizeof(ctx));
297		for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
298			ctx.handle = i;
299			if (copy_to_user(&res->contexts[i], &ctx, sizeof(ctx)))
300				return -EFAULT;
301		}
302	}
303	res->count = DRM_RESERVED_CONTEXTS;
304
305	return 0;
306}
307
308/**
309 * Add context.
310 *
311 * \param inode device inode.
312 * \param file_priv DRM file private.
313 * \param cmd command.
314 * \param arg user argument pointing to a drm_ctx structure.
315 * \return zero on success or a negative number on failure.
316 *
317 * Get a new handle for the context and copy to userspace.
318 */
319int drm_addctx(struct drm_device *dev, void *data,
320	       struct drm_file *file_priv)
321{
322	struct drm_ctx_list *ctx_entry;
323	struct drm_ctx *ctx = data;
324
325	ctx->handle = drm_ctxbitmap_next(dev);
326	if (ctx->handle == DRM_KERNEL_CONTEXT) {
327		/* Skip kernel's context and get a new one. */
328		ctx->handle = drm_ctxbitmap_next(dev);
329	}
330	DRM_DEBUG("%d\n", ctx->handle);
331	if (ctx->handle == -1) {
332		DRM_DEBUG("Not enough free contexts.\n");
333		/* Should this return -EBUSY instead? */
334		return -ENOMEM;
335	}
336
337	ctx_entry = kmalloc(sizeof(*ctx_entry), GFP_KERNEL);
338	if (!ctx_entry) {
339		DRM_DEBUG("out of memory\n");
340		return -ENOMEM;
341	}
342
343	INIT_LIST_HEAD(&ctx_entry->head);
344	ctx_entry->handle = ctx->handle;
345	ctx_entry->tag = file_priv;
346
347	mutex_lock(&dev->ctxlist_mutex);
348	list_add(&ctx_entry->head, &dev->ctxlist);
349	++dev->ctx_count;
350	mutex_unlock(&dev->ctxlist_mutex);
351
352	return 0;
353}
354
355int drm_modctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
356{
357	/* This does nothing */
358	return 0;
359}
360
361/**
362 * Get context.
363 *
364 * \param inode device inode.
365 * \param file_priv DRM file private.
366 * \param cmd command.
367 * \param arg user argument pointing to a drm_ctx structure.
368 * \return zero on success or a negative number on failure.
369 */
370int drm_getctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
371{
372	struct drm_ctx *ctx = data;
373
374	/* This is 0, because we don't handle any context flags */
375	ctx->flags = 0;
376
377	return 0;
378}
379
380/**
381 * Switch context.
382 *
383 * \param inode device inode.
384 * \param file_priv DRM file private.
385 * \param cmd command.
386 * \param arg user argument pointing to a drm_ctx structure.
387 * \return zero on success or a negative number on failure.
388 *
389 * Calls context_switch().
390 */
391int drm_switchctx(struct drm_device *dev, void *data,
392		  struct drm_file *file_priv)
393{
394	struct drm_ctx *ctx = data;
395
396	DRM_DEBUG("%d\n", ctx->handle);
397	return drm_context_switch(dev, dev->last_context, ctx->handle);
398}
399
400/**
401 * New context.
402 *
403 * \param inode device inode.
404 * \param file_priv DRM file private.
405 * \param cmd command.
406 * \param arg user argument pointing to a drm_ctx structure.
407 * \return zero on success or a negative number on failure.
408 *
409 * Calls context_switch_complete().
410 */
411int drm_newctx(struct drm_device *dev, void *data,
412	       struct drm_file *file_priv)
413{
414	struct drm_ctx *ctx = data;
415
416	DRM_DEBUG("%d\n", ctx->handle);
417	drm_context_switch_complete(dev, file_priv, ctx->handle);
418
419	return 0;
420}
421
422/**
423 * Remove context.
424 *
425 * \param inode device inode.
426 * \param file_priv DRM file private.
427 * \param cmd command.
428 * \param arg user argument pointing to a drm_ctx structure.
429 * \return zero on success or a negative number on failure.
430 *
431 * If not the special kernel context, calls ctxbitmap_free() to free the specified context.
432 */
433int drm_rmctx(struct drm_device *dev, void *data,
434	      struct drm_file *file_priv)
435{
436	struct drm_ctx *ctx = data;
437
438	DRM_DEBUG("%d\n", ctx->handle);
439	if (ctx->handle != DRM_KERNEL_CONTEXT) {
440		if (dev->driver->context_dtor)
441			dev->driver->context_dtor(dev, ctx->handle);
442		drm_ctxbitmap_free(dev, ctx->handle);
443	}
444
445	mutex_lock(&dev->ctxlist_mutex);
446	if (!list_empty(&dev->ctxlist)) {
447		struct drm_ctx_list *pos, *n;
448
449		list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
450			if (pos->handle == ctx->handle) {
451				list_del(&pos->head);
452				kfree(pos);
453				--dev->ctx_count;
454			}
455		}
456	}
457	mutex_unlock(&dev->ctxlist_mutex);
458
459	return 0;
460}
461
462/*@}*/
463