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#include <sys/cdefs.h>
37/*
38 * ChangeLog:
39 *  2001-11-16	Torsten Duwe <duwe@caldera.de>
40 *		added context constructor/destructor hooks,
41 *		needed by SiS driver's memory management.
42 */
43
44#include <dev/drm2/drmP.h>
45
46/******************************************************************/
47/** \name Context bitmap support */
48/*@{*/
49
50/**
51 * Free a handle from the context bitmap.
52 *
53 * \param dev DRM device.
54 * \param ctx_handle context handle.
55 *
56 * Clears the bit specified by \p ctx_handle in drm_device::ctx_bitmap and the entry
57 * in drm_device::ctx_idr, while holding the drm_device::struct_mutex
58 * lock.
59 */
60void drm_ctxbitmap_free(struct drm_device * dev, int ctx_handle)
61{
62	if (ctx_handle < 0 || ctx_handle >= DRM_MAX_CTXBITMAP ||
63	    dev->ctx_bitmap == NULL) {
64		DRM_ERROR("Attempt to free invalid context handle: %d\n",
65		   ctx_handle);
66		return;
67	}
68
69	DRM_LOCK(dev);
70	clear_bit(ctx_handle, dev->ctx_bitmap);
71	dev->context_sareas[ctx_handle] = NULL;
72	DRM_UNLOCK(dev);
73}
74
75/**
76 * Context bitmap allocation.
77 *
78 * \param dev DRM device.
79 * \return (non-negative) context handle on success or a negative number on failure.
80 *
81 * Allocate a new idr from drm_device::ctx_idr while holding the
82 * drm_device::struct_mutex lock.
83 */
84static int drm_ctxbitmap_next(struct drm_device * dev)
85{
86	int bit;
87
88	if (dev->ctx_bitmap == NULL)
89		return -1;
90
91	DRM_LOCK(dev);
92	bit = find_first_zero_bit(dev->ctx_bitmap, DRM_MAX_CTXBITMAP);
93	if (bit >= DRM_MAX_CTXBITMAP) {
94		DRM_UNLOCK(dev);
95		return -1;
96	}
97
98	set_bit(bit, dev->ctx_bitmap);
99	DRM_DEBUG("bit : %d\n", bit);
100	if ((bit+1) > dev->max_context) {
101		struct drm_local_map **ctx_sareas;
102		int max_ctx = (bit+1);
103
104		ctx_sareas = realloc(dev->context_sareas,
105		    max_ctx * sizeof(*dev->context_sareas),
106		    DRM_MEM_SAREA, M_NOWAIT);
107		if (ctx_sareas == NULL) {
108			clear_bit(bit, dev->ctx_bitmap);
109			DRM_DEBUG("failed to allocate bit : %d\n", bit);
110			DRM_UNLOCK(dev);
111			return -1;
112		}
113		dev->max_context = max_ctx;
114		dev->context_sareas = ctx_sareas;
115		dev->context_sareas[bit] = NULL;
116	}
117	DRM_UNLOCK(dev);
118	return bit;
119}
120
121/**
122 * Context bitmap initialization.
123 *
124 * \param dev DRM device.
125 *
126 * Initialise the drm_device::ctx_idr
127 */
128int drm_ctxbitmap_init(struct drm_device * dev)
129{
130	int i;
131   	int temp;
132
133	DRM_LOCK(dev);
134	dev->ctx_bitmap = malloc(PAGE_SIZE, DRM_MEM_CTXBITMAP,
135	    M_NOWAIT | M_ZERO);
136	if (dev->ctx_bitmap == NULL) {
137		DRM_UNLOCK(dev);
138		return ENOMEM;
139	}
140	dev->context_sareas = NULL;
141	dev->max_context = -1;
142	DRM_UNLOCK(dev);
143
144	for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
145		temp = drm_ctxbitmap_next(dev);
146		DRM_DEBUG("drm_ctxbitmap_init : %d\n", temp);
147	}
148
149	return 0;
150}
151
152/**
153 * Context bitmap cleanup.
154 *
155 * \param dev DRM device.
156 *
157 * Free all idr members using drm_ctx_sarea_free helper function
158 * while holding the drm_device::struct_mutex lock.
159 */
160void drm_ctxbitmap_cleanup(struct drm_device * dev)
161{
162	DRM_LOCK(dev);
163	if (dev->context_sareas != NULL)
164		free(dev->context_sareas, DRM_MEM_SAREA);
165	free(dev->ctx_bitmap, DRM_MEM_CTXBITMAP);
166	DRM_UNLOCK(dev);
167}
168
169/*@}*/
170
171/******************************************************************/
172/** \name Per Context SAREA Support */
173/*@{*/
174
175/**
176 * Get 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 * Gets the map from drm_device::ctx_idr with the handle specified and
185 * returns its handle.
186 */
187int drm_getsareactx(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;
192
193	DRM_LOCK(dev);
194	if (dev->max_context < 0 ||
195	    request->ctx_id >= (unsigned) dev->max_context) {
196		DRM_UNLOCK(dev);
197		return EINVAL;
198	}
199
200	map = dev->context_sareas[request->ctx_id];
201	DRM_UNLOCK(dev);
202
203	request->handle = (void *)map->handle;
204
205	return 0;
206}
207
208/**
209 * Set per-context SAREA.
210 *
211 * \param inode device inode.
212 * \param file_priv DRM file private.
213 * \param cmd command.
214 * \param arg user argument pointing to a drm_ctx_priv_map structure.
215 * \return zero on success or a negative number on failure.
216 *
217 * Searches the mapping specified in \p arg and update the entry in
218 * drm_device::ctx_idr with it.
219 */
220int drm_setsareactx(struct drm_device *dev, void *data,
221		    struct drm_file *file_priv)
222{
223	struct drm_ctx_priv_map *request = data;
224	struct drm_local_map *map = NULL;
225	struct drm_map_list *r_list = NULL;
226
227	DRM_LOCK(dev);
228	list_for_each_entry(r_list, &dev->maplist, head) {
229		if (r_list->map
230		    && r_list->user_token == (unsigned long) request->handle) {
231			if (dev->max_context < 0)
232				goto bad;
233			if (request->ctx_id >= (unsigned) dev->max_context)
234				goto bad;
235			dev->context_sareas[request->ctx_id] = map;
236			DRM_UNLOCK(dev);
237			return 0;
238		}
239	}
240
241bad:
242	DRM_UNLOCK(dev);
243	return EINVAL;
244}
245
246/*@}*/
247
248/******************************************************************/
249/** \name The actual DRM context handling routines */
250/*@{*/
251
252/**
253 * Switch context.
254 *
255 * \param dev DRM device.
256 * \param old old context handle.
257 * \param new new context handle.
258 * \return zero on success or a negative number on failure.
259 *
260 * Attempt to set drm_device::context_flag.
261 */
262static int drm_context_switch(struct drm_device * dev, int old, int new)
263{
264	if (test_and_set_bit(0, &dev->context_flag)) {
265		DRM_ERROR("Reentering -- FIXME\n");
266		return -EBUSY;
267	}
268
269	DRM_DEBUG("Context switch from %d to %d\n", old, new);
270
271	if (new == dev->last_context) {
272		clear_bit(0, &dev->context_flag);
273		return 0;
274	}
275
276	return 0;
277}
278
279/**
280 * Complete context switch.
281 *
282 * \param dev DRM device.
283 * \param new new context handle.
284 * \return zero on success or a negative number on failure.
285 *
286 * Updates drm_device::last_context and drm_device::last_switch. Verifies the
287 * hardware lock is held, clears the drm_device::context_flag and wakes up
288 * drm_device::context_wait.
289 */
290static int drm_context_switch_complete(struct drm_device *dev,
291				       struct drm_file *file_priv, int new)
292{
293	dev->last_context = new;	/* PRE/POST: This is the _only_ writer. */
294	dev->last_switch = jiffies;
295
296	if (!_DRM_LOCK_IS_HELD(file_priv->master->lock.hw_lock->lock)) {
297		DRM_ERROR("Lock isn't held after context switch\n");
298	}
299
300	/* If a context switch is ever initiated
301	   when the kernel holds the lock, release
302	   that lock here. */
303	clear_bit(0, &dev->context_flag);
304	wakeup(&dev->context_wait);
305
306	return 0;
307}
308
309/**
310 * Reserve contexts.
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_res structure.
316 * \return zero on success or a negative number on failure.
317 */
318int drm_resctx(struct drm_device *dev, void *data,
319	       struct drm_file *file_priv)
320{
321	struct drm_ctx_res *res = data;
322	struct drm_ctx ctx;
323	int i;
324
325	if (res->count >= DRM_RESERVED_CONTEXTS) {
326		memset(&ctx, 0, sizeof(ctx));
327		for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
328			ctx.handle = i;
329			if (copy_to_user(&res->contexts[i], &ctx, sizeof(ctx)))
330				return -EFAULT;
331		}
332	}
333	res->count = DRM_RESERVED_CONTEXTS;
334
335	return 0;
336}
337
338/**
339 * Add context.
340 *
341 * \param inode device inode.
342 * \param file_priv DRM file private.
343 * \param cmd command.
344 * \param arg user argument pointing to a drm_ctx structure.
345 * \return zero on success or a negative number on failure.
346 *
347 * Get a new handle for the context and copy to userspace.
348 */
349int drm_addctx(struct drm_device *dev, void *data,
350	       struct drm_file *file_priv)
351{
352	struct drm_ctx_list *ctx_entry;
353	struct drm_ctx *ctx = data;
354
355	ctx->handle = drm_ctxbitmap_next(dev);
356	if (ctx->handle == DRM_KERNEL_CONTEXT) {
357		/* Skip kernel's context and get a new one. */
358		ctx->handle = drm_ctxbitmap_next(dev);
359	}
360	DRM_DEBUG("%d\n", ctx->handle);
361	if (ctx->handle == -1) {
362		DRM_DEBUG("Not enough free contexts.\n");
363		/* Should this return -EBUSY instead? */
364		return -ENOMEM;
365	}
366
367	ctx_entry = malloc(sizeof(*ctx_entry), DRM_MEM_CTXBITMAP, M_NOWAIT);
368	if (!ctx_entry) {
369		DRM_DEBUG("out of memory\n");
370		return -ENOMEM;
371	}
372
373	INIT_LIST_HEAD(&ctx_entry->head);
374	ctx_entry->handle = ctx->handle;
375	ctx_entry->tag = file_priv;
376
377	DRM_LOCK(dev);
378	list_add(&ctx_entry->head, &dev->ctxlist);
379	++dev->ctx_count;
380	DRM_UNLOCK(dev);
381
382	return 0;
383}
384
385int drm_modctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
386{
387	/* This does nothing */
388	return 0;
389}
390
391/**
392 * Get context.
393 *
394 * \param inode device inode.
395 * \param file_priv DRM file private.
396 * \param cmd command.
397 * \param arg user argument pointing to a drm_ctx structure.
398 * \return zero on success or a negative number on failure.
399 */
400int drm_getctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
401{
402	struct drm_ctx *ctx = data;
403
404	/* This is 0, because we don't handle any context flags */
405	ctx->flags = 0;
406
407	return 0;
408}
409
410/**
411 * Switch context.
412 *
413 * \param inode device inode.
414 * \param file_priv DRM file private.
415 * \param cmd command.
416 * \param arg user argument pointing to a drm_ctx structure.
417 * \return zero on success or a negative number on failure.
418 *
419 * Calls context_switch().
420 */
421int drm_switchctx(struct drm_device *dev, void *data,
422		  struct drm_file *file_priv)
423{
424	struct drm_ctx *ctx = data;
425
426	DRM_DEBUG("%d\n", ctx->handle);
427	return drm_context_switch(dev, dev->last_context, ctx->handle);
428}
429
430/**
431 * New context.
432 *
433 * \param inode device inode.
434 * \param file_priv DRM file private.
435 * \param cmd command.
436 * \param arg user argument pointing to a drm_ctx structure.
437 * \return zero on success or a negative number on failure.
438 *
439 * Calls context_switch_complete().
440 */
441int drm_newctx(struct drm_device *dev, void *data,
442	       struct drm_file *file_priv)
443{
444	struct drm_ctx *ctx = data;
445
446	DRM_DEBUG("%d\n", ctx->handle);
447	drm_context_switch_complete(dev, file_priv, ctx->handle);
448
449	return 0;
450}
451
452/**
453 * Remove context.
454 *
455 * \param inode device inode.
456 * \param file_priv DRM file private.
457 * \param cmd command.
458 * \param arg user argument pointing to a drm_ctx structure.
459 * \return zero on success or a negative number on failure.
460 *
461 * If not the special kernel context, calls ctxbitmap_free() to free the specified context.
462 */
463int drm_rmctx(struct drm_device *dev, void *data,
464	      struct drm_file *file_priv)
465{
466	struct drm_ctx *ctx = data;
467
468	DRM_DEBUG("%d\n", ctx->handle);
469	if (ctx->handle != DRM_KERNEL_CONTEXT) {
470		if (dev->driver->context_dtor)
471			dev->driver->context_dtor(dev, ctx->handle);
472		drm_ctxbitmap_free(dev, ctx->handle);
473	}
474
475	DRM_LOCK(dev);
476	if (!list_empty(&dev->ctxlist)) {
477		struct drm_ctx_list *pos, *n;
478
479		list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
480			if (pos->handle == ctx->handle) {
481				list_del(&pos->head);
482				free(pos, DRM_MEM_CTXBITMAP);
483				--dev->ctx_count;
484			}
485		}
486	}
487	DRM_UNLOCK(dev);
488
489	return 0;
490}
491
492/*@}*/
493