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