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__FBSDID("$FreeBSD$");
38
39/*
40 * ChangeLog:
41 *  2001-11-16	Torsten Duwe <duwe@caldera.de>
42 *		added context constructor/destructor hooks,
43 *		needed by SiS driver's memory management.
44 */
45
46#include <dev/drm2/drmP.h>
47
48/******************************************************************/
49/** \name Context bitmap support */
50/*@{*/
51
52/**
53 * Free a handle from the context bitmap.
54 *
55 * \param dev DRM device.
56 * \param ctx_handle context handle.
57 *
58 * Clears the bit specified by \p ctx_handle in drm_device::ctx_bitmap and the entry
59 * in drm_device::ctx_idr, while holding the drm_device::struct_mutex
60 * lock.
61 */
62void drm_ctxbitmap_free(struct drm_device * dev, int ctx_handle)
63{
64	if (ctx_handle < 0 || ctx_handle >= DRM_MAX_CTXBITMAP ||
65	    dev->ctx_bitmap == NULL) {
66		DRM_ERROR("Attempt to free invalid context handle: %d\n",
67		   ctx_handle);
68		return;
69	}
70
71	DRM_LOCK(dev);
72	clear_bit(ctx_handle, dev->ctx_bitmap);
73	dev->context_sareas[ctx_handle] = NULL;
74	DRM_UNLOCK(dev);
75}
76
77/**
78 * Context bitmap allocation.
79 *
80 * \param dev DRM device.
81 * \return (non-negative) context handle on success or a negative number on failure.
82 *
83 * Allocate a new idr from drm_device::ctx_idr while holding the
84 * drm_device::struct_mutex lock.
85 */
86static int drm_ctxbitmap_next(struct drm_device * dev)
87{
88	int bit;
89
90	if (dev->ctx_bitmap == NULL)
91		return -1;
92
93	DRM_LOCK(dev);
94	bit = find_first_zero_bit(dev->ctx_bitmap, DRM_MAX_CTXBITMAP);
95	if (bit >= DRM_MAX_CTXBITMAP) {
96		DRM_UNLOCK(dev);
97		return -1;
98	}
99
100	set_bit(bit, dev->ctx_bitmap);
101	DRM_DEBUG("bit : %d\n", bit);
102	if ((bit+1) > dev->max_context) {
103		struct drm_local_map **ctx_sareas;
104		int max_ctx = (bit+1);
105
106		ctx_sareas = realloc(dev->context_sareas,
107		    max_ctx * sizeof(*dev->context_sareas),
108		    DRM_MEM_SAREA, M_NOWAIT);
109		if (ctx_sareas == NULL) {
110			clear_bit(bit, dev->ctx_bitmap);
111			DRM_DEBUG("failed to allocate bit : %d\n", bit);
112			DRM_UNLOCK(dev);
113			return -1;
114		}
115		dev->max_context = max_ctx;
116		dev->context_sareas = ctx_sareas;
117		dev->context_sareas[bit] = NULL;
118	}
119	DRM_UNLOCK(dev);
120	return bit;
121}
122
123/**
124 * Context bitmap initialization.
125 *
126 * \param dev DRM device.
127 *
128 * Initialise the drm_device::ctx_idr
129 */
130int drm_ctxbitmap_init(struct drm_device * dev)
131{
132	int i;
133   	int temp;
134
135	DRM_LOCK(dev);
136	dev->ctx_bitmap = malloc(PAGE_SIZE, DRM_MEM_CTXBITMAP,
137	    M_NOWAIT | M_ZERO);
138	if (dev->ctx_bitmap == NULL) {
139		DRM_UNLOCK(dev);
140		return ENOMEM;
141	}
142	dev->context_sareas = NULL;
143	dev->max_context = -1;
144	DRM_UNLOCK(dev);
145
146	for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
147		temp = drm_ctxbitmap_next(dev);
148		DRM_DEBUG("drm_ctxbitmap_init : %d\n", temp);
149	}
150
151	return 0;
152}
153
154/**
155 * Context bitmap cleanup.
156 *
157 * \param dev DRM device.
158 *
159 * Free all idr members using drm_ctx_sarea_free helper function
160 * while holding the drm_device::struct_mutex lock.
161 */
162void drm_ctxbitmap_cleanup(struct drm_device * dev)
163{
164	DRM_LOCK(dev);
165	if (dev->context_sareas != NULL)
166		free(dev->context_sareas, DRM_MEM_SAREA);
167	free(dev->ctx_bitmap, DRM_MEM_CTXBITMAP);
168	DRM_UNLOCK(dev);
169}
170
171/*@}*/
172
173/******************************************************************/
174/** \name Per Context SAREA Support */
175/*@{*/
176
177/**
178 * Get per-context SAREA.
179 *
180 * \param inode device inode.
181 * \param file_priv DRM file private.
182 * \param cmd command.
183 * \param arg user argument pointing to a drm_ctx_priv_map structure.
184 * \return zero on success or a negative number on failure.
185 *
186 * Gets the map from drm_device::ctx_idr with the handle specified and
187 * returns its handle.
188 */
189int drm_getsareactx(struct drm_device *dev, void *data,
190		    struct drm_file *file_priv)
191{
192	struct drm_ctx_priv_map *request = data;
193	struct drm_local_map *map;
194
195	DRM_LOCK(dev);
196	if (dev->max_context < 0 ||
197	    request->ctx_id >= (unsigned) dev->max_context) {
198		DRM_UNLOCK(dev);
199		return EINVAL;
200	}
201
202	map = dev->context_sareas[request->ctx_id];
203	DRM_UNLOCK(dev);
204
205	request->handle = (void *)map->handle;
206
207	return 0;
208}
209
210/**
211 * Set per-context SAREA.
212 *
213 * \param inode device inode.
214 * \param file_priv DRM file private.
215 * \param cmd command.
216 * \param arg user argument pointing to a drm_ctx_priv_map structure.
217 * \return zero on success or a negative number on failure.
218 *
219 * Searches the mapping specified in \p arg and update the entry in
220 * drm_device::ctx_idr with it.
221 */
222int drm_setsareactx(struct drm_device *dev, void *data,
223		    struct drm_file *file_priv)
224{
225	struct drm_ctx_priv_map *request = data;
226	struct drm_local_map *map = NULL;
227	struct drm_map_list *r_list = NULL;
228
229	DRM_LOCK(dev);
230	list_for_each_entry(r_list, &dev->maplist, head) {
231		if (r_list->map
232		    && r_list->user_token == (unsigned long) request->handle) {
233			if (dev->max_context < 0)
234				goto bad;
235			if (request->ctx_id >= (unsigned) dev->max_context)
236				goto bad;
237			dev->context_sareas[request->ctx_id] = map;
238			DRM_UNLOCK(dev);
239			return 0;
240		}
241	}
242
243bad:
244	DRM_UNLOCK(dev);
245	return EINVAL;
246}
247
248/*@}*/
249
250/******************************************************************/
251/** \name The actual DRM context handling routines */
252/*@{*/
253
254/**
255 * Switch context.
256 *
257 * \param dev DRM device.
258 * \param old old context handle.
259 * \param new new context handle.
260 * \return zero on success or a negative number on failure.
261 *
262 * Attempt to set drm_device::context_flag.
263 */
264static int drm_context_switch(struct drm_device * dev, int old, int new)
265{
266	if (test_and_set_bit(0, &dev->context_flag)) {
267		DRM_ERROR("Reentering -- FIXME\n");
268		return -EBUSY;
269	}
270
271	DRM_DEBUG("Context switch from %d to %d\n", old, new);
272
273	if (new == dev->last_context) {
274		clear_bit(0, &dev->context_flag);
275		return 0;
276	}
277
278	return 0;
279}
280
281/**
282 * Complete context switch.
283 *
284 * \param dev DRM device.
285 * \param new new context handle.
286 * \return zero on success or a negative number on failure.
287 *
288 * Updates drm_device::last_context and drm_device::last_switch. Verifies the
289 * hardware lock is held, clears the drm_device::context_flag and wakes up
290 * drm_device::context_wait.
291 */
292static int drm_context_switch_complete(struct drm_device *dev,
293				       struct drm_file *file_priv, int new)
294{
295	dev->last_context = new;	/* PRE/POST: This is the _only_ writer. */
296	dev->last_switch = jiffies;
297
298	if (!_DRM_LOCK_IS_HELD(file_priv->master->lock.hw_lock->lock)) {
299		DRM_ERROR("Lock isn't held after context switch\n");
300	}
301
302	/* If a context switch is ever initiated
303	   when the kernel holds the lock, release
304	   that lock here. */
305	clear_bit(0, &dev->context_flag);
306	wakeup(&dev->context_wait);
307
308	return 0;
309}
310
311/**
312 * Reserve contexts.
313 *
314 * \param inode device inode.
315 * \param file_priv DRM file private.
316 * \param cmd command.
317 * \param arg user argument pointing to a drm_ctx_res structure.
318 * \return zero on success or a negative number on failure.
319 */
320int drm_resctx(struct drm_device *dev, void *data,
321	       struct drm_file *file_priv)
322{
323	struct drm_ctx_res *res = data;
324	struct drm_ctx ctx;
325	int i;
326
327	if (res->count >= DRM_RESERVED_CONTEXTS) {
328		memset(&ctx, 0, sizeof(ctx));
329		for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
330			ctx.handle = i;
331			if (copy_to_user(&res->contexts[i], &ctx, sizeof(ctx)))
332				return -EFAULT;
333		}
334	}
335	res->count = DRM_RESERVED_CONTEXTS;
336
337	return 0;
338}
339
340/**
341 * Add context.
342 *
343 * \param inode device inode.
344 * \param file_priv DRM file private.
345 * \param cmd command.
346 * \param arg user argument pointing to a drm_ctx structure.
347 * \return zero on success or a negative number on failure.
348 *
349 * Get a new handle for the context and copy to userspace.
350 */
351int drm_addctx(struct drm_device *dev, void *data,
352	       struct drm_file *file_priv)
353{
354	struct drm_ctx_list *ctx_entry;
355	struct drm_ctx *ctx = data;
356
357	ctx->handle = drm_ctxbitmap_next(dev);
358	if (ctx->handle == DRM_KERNEL_CONTEXT) {
359		/* Skip kernel's context and get a new one. */
360		ctx->handle = drm_ctxbitmap_next(dev);
361	}
362	DRM_DEBUG("%d\n", ctx->handle);
363	if (ctx->handle == -1) {
364		DRM_DEBUG("Not enough free contexts.\n");
365		/* Should this return -EBUSY instead? */
366		return -ENOMEM;
367	}
368
369	ctx_entry = malloc(sizeof(*ctx_entry), DRM_MEM_CTXBITMAP, M_NOWAIT);
370	if (!ctx_entry) {
371		DRM_DEBUG("out of memory\n");
372		return -ENOMEM;
373	}
374
375	INIT_LIST_HEAD(&ctx_entry->head);
376	ctx_entry->handle = ctx->handle;
377	ctx_entry->tag = file_priv;
378
379	DRM_LOCK(dev);
380	list_add(&ctx_entry->head, &dev->ctxlist);
381	++dev->ctx_count;
382	DRM_UNLOCK(dev);
383
384	return 0;
385}
386
387int drm_modctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
388{
389	/* This does nothing */
390	return 0;
391}
392
393/**
394 * Get context.
395 *
396 * \param inode device inode.
397 * \param file_priv DRM file private.
398 * \param cmd command.
399 * \param arg user argument pointing to a drm_ctx structure.
400 * \return zero on success or a negative number on failure.
401 */
402int drm_getctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
403{
404	struct drm_ctx *ctx = data;
405
406	/* This is 0, because we don't handle any context flags */
407	ctx->flags = 0;
408
409	return 0;
410}
411
412/**
413 * Switch context.
414 *
415 * \param inode device inode.
416 * \param file_priv DRM file private.
417 * \param cmd command.
418 * \param arg user argument pointing to a drm_ctx structure.
419 * \return zero on success or a negative number on failure.
420 *
421 * Calls context_switch().
422 */
423int drm_switchctx(struct drm_device *dev, void *data,
424		  struct drm_file *file_priv)
425{
426	struct drm_ctx *ctx = data;
427
428	DRM_DEBUG("%d\n", ctx->handle);
429	return drm_context_switch(dev, dev->last_context, ctx->handle);
430}
431
432/**
433 * New context.
434 *
435 * \param inode device inode.
436 * \param file_priv DRM file private.
437 * \param cmd command.
438 * \param arg user argument pointing to a drm_ctx structure.
439 * \return zero on success or a negative number on failure.
440 *
441 * Calls context_switch_complete().
442 */
443int drm_newctx(struct drm_device *dev, void *data,
444	       struct drm_file *file_priv)
445{
446	struct drm_ctx *ctx = data;
447
448	DRM_DEBUG("%d\n", ctx->handle);
449	drm_context_switch_complete(dev, file_priv, ctx->handle);
450
451	return 0;
452}
453
454/**
455 * Remove context.
456 *
457 * \param inode device inode.
458 * \param file_priv DRM file private.
459 * \param cmd command.
460 * \param arg user argument pointing to a drm_ctx structure.
461 * \return zero on success or a negative number on failure.
462 *
463 * If not the special kernel context, calls ctxbitmap_free() to free the specified context.
464 */
465int drm_rmctx(struct drm_device *dev, void *data,
466	      struct drm_file *file_priv)
467{
468	struct drm_ctx *ctx = data;
469
470	DRM_DEBUG("%d\n", ctx->handle);
471	if (ctx->handle != DRM_KERNEL_CONTEXT) {
472		if (dev->driver->context_dtor)
473			dev->driver->context_dtor(dev, ctx->handle);
474		drm_ctxbitmap_free(dev, ctx->handle);
475	}
476
477	DRM_LOCK(dev);
478	if (!list_empty(&dev->ctxlist)) {
479		struct drm_ctx_list *pos, *n;
480
481		list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
482			if (pos->handle == ctx->handle) {
483				list_del(&pos->head);
484				free(pos, DRM_MEM_CTXBITMAP);
485				--dev->ctx_count;
486			}
487		}
488	}
489	DRM_UNLOCK(dev);
490
491	return 0;
492}
493
494/*@}*/
495