1 /*-
2  * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
3  * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
4  * All Rights Reserved.
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a
7  * copy of this software and associated documentation files (the "Software"),
8  * to deal in the Software without restriction, including without limitation
9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10  * and/or sell copies of the Software, and to permit persons to whom the
11  * Software is furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice (including the next
14  * paragraph) shall be included in all copies or substantial portions of the
15  * Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
20  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
21  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
22  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
23  * OTHER DEALINGS IN THE SOFTWARE.
24  *
25  * Authors:
26  *    Rickard E. (Rik) Faith <faith@valinux.com>
27  *    Gareth Hughes <gareth@valinux.com>
28  *
29  */
30 
31 /** @file drm_context.c
32  * Implementation of the context management ioctls.
33  */
34 
35 #include "drmP.h"
36 
37 /* ================================================================
38  * Context bitmap support
39  */
40 
41 void drm_ctxbitmap_free(struct drm_device *dev, int ctx_handle)
42 {
43 	if (ctx_handle < 0 || ctx_handle >= DRM_MAX_CTXBITMAP ||
44 	    dev->ctx_bitmap == NULL) {
45 		DRM_ERROR("Attempt to free invalid context handle: %d\n",
46 		   ctx_handle);
47 		return;
48 	}
49 
50 	DRM_LOCK();
51 	clear_bit(ctx_handle, dev->ctx_bitmap);
52 	dev->context_sareas[ctx_handle] = NULL;
53 	DRM_UNLOCK();
54 	return;
55 }
56 
57 int drm_ctxbitmap_next(struct drm_device *dev)
58 {
59 	int bit;
60 
61 	if (dev->ctx_bitmap == NULL)
62 		return -1;
63 
64 	DRM_LOCK();
65 	bit = find_first_zero_bit(dev->ctx_bitmap, DRM_MAX_CTXBITMAP);
66 	if (bit >= DRM_MAX_CTXBITMAP) {
67 		DRM_UNLOCK();
68 		return -1;
69 	}
70 
71 	set_bit(bit, dev->ctx_bitmap);
72 	DRM_DEBUG("drm_ctxbitmap_next bit : %d\n", bit);
73 	if ((bit+1) > dev->max_context) {
74 		dev->max_context = (bit+1);
75 		if (dev->context_sareas != NULL) {
76 			drm_local_map_t **ctx_sareas;
77 
78 			ctx_sareas = realloc(dev->context_sareas,
79 			    dev->max_context * sizeof(*dev->context_sareas),
80 			    DRM_MEM_SAREA, M_NOWAIT);
81 			if (ctx_sareas == NULL) {
82 				clear_bit(bit, dev->ctx_bitmap);
83 				DRM_UNLOCK();
84 				return -1;
85 			}
86 			dev->context_sareas = ctx_sareas;
87 			dev->context_sareas[bit] = NULL;
88 		} else {
89 			/* max_context == 1 at this point */
90 			dev->context_sareas = malloc(dev->max_context *
91 			    sizeof(*dev->context_sareas), DRM_MEM_SAREA,
92 			    M_NOWAIT);
93 			if (dev->context_sareas == NULL) {
94 				clear_bit(bit, dev->ctx_bitmap);
95 				DRM_UNLOCK();
96 				return -1;
97 			}
98 			dev->context_sareas[bit] = NULL;
99 		}
100 	}
101 	DRM_UNLOCK();
102 	return bit;
103 }
104 
105 int drm_ctxbitmap_init(struct drm_device *dev)
106 {
107 	int i;
108    	int temp;
109 
110 	DRM_LOCK();
111 	dev->ctx_bitmap = malloc(PAGE_SIZE, DRM_MEM_CTXBITMAP,
112 	    M_NOWAIT | M_ZERO);
113 	if (dev->ctx_bitmap == NULL) {
114 		DRM_UNLOCK();
115 		return ENOMEM;
116 	}
117 	dev->context_sareas = NULL;
118 	dev->max_context = -1;
119 	DRM_UNLOCK();
120 
121 	for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
122 		temp = drm_ctxbitmap_next(dev);
123 		DRM_DEBUG("drm_ctxbitmap_init : %d\n", temp);
124 	}
125 
126 	return 0;
127 }
128 
129 void drm_ctxbitmap_cleanup(struct drm_device *dev)
130 {
131 	DRM_LOCK();
132 	if (dev->context_sareas != NULL)
133 		free(dev->context_sareas, DRM_MEM_SAREA);
134 	free(dev->ctx_bitmap, DRM_MEM_CTXBITMAP);
135 	DRM_UNLOCK();
136 }
137 
138 /* ================================================================
139  * Per Context SAREA Support
140  */
141 
142 int drm_getsareactx(struct drm_device *dev, void *data,
143 		    struct drm_file *file_priv)
144 {
145 	struct drm_ctx_priv_map *request = data;
146 	drm_local_map_t *map;
147 
148 	DRM_LOCK();
149 	if (dev->max_context < 0 ||
150 	    request->ctx_id >= (unsigned) dev->max_context) {
151 		DRM_UNLOCK();
152 		return EINVAL;
153 	}
154 
155 	map = dev->context_sareas[request->ctx_id];
156 	DRM_UNLOCK();
157 
158 	request->handle = map->handle;
159 
160 	return 0;
161 }
162 
163 int drm_setsareactx(struct drm_device *dev, void *data,
164 		    struct drm_file *file_priv)
165 {
166 	struct drm_ctx_priv_map *request = data;
167 	drm_local_map_t *map = NULL;
168 
169 	DRM_LOCK();
170 	TAILQ_FOREACH(map, &dev->maplist, link) {
171 		if (map->handle == request->handle) {
172 			if (dev->max_context < 0)
173 				goto bad;
174 			if (request->ctx_id >= (unsigned) dev->max_context)
175 				goto bad;
176 			dev->context_sareas[request->ctx_id] = map;
177 			DRM_UNLOCK();
178 			return 0;
179 		}
180 	}
181 
182 bad:
183 	DRM_UNLOCK();
184 	return EINVAL;
185 }
186 
187 /* ================================================================
188  * The actual DRM context handling routines
189  */
190 
191 int drm_context_switch(struct drm_device *dev, int old, int new)
192 {
193 	if (test_and_set_bit(0, &dev->context_flag)) {
194 		DRM_ERROR("Reentering -- FIXME\n");
195 		return EBUSY;
196 	}
197 
198 	DRM_DEBUG("Context switch from %d to %d\n", old, new);
199 
200 	if (new == dev->last_context) {
201 		clear_bit(0, &dev->context_flag);
202 		return 0;
203 	}
204 
205 	return 0;
206 }
207 
208 int drm_context_switch_complete(struct drm_device *dev, int new)
209 {
210 	dev->last_context = new;  /* PRE/POST: This is the _only_ writer. */
211 
212 	if (!_DRM_LOCK_IS_HELD(dev->lock.hw_lock->lock)) {
213 		DRM_ERROR("Lock isn't held after context switch\n");
214 	}
215 
216 	/* If a context switch is ever initiated
217 	   when the kernel holds the lock, release
218 	   that lock here. */
219 	clear_bit(0, &dev->context_flag);
220 
221 	return 0;
222 }
223 
224 int drm_resctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
225 {
226 	struct drm_ctx_res *res = data;
227 	struct drm_ctx ctx;
228 	int i;
229 
230 	if (res->count >= DRM_RESERVED_CONTEXTS) {
231 		bzero(&ctx, sizeof(ctx));
232 		for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
233 			ctx.handle = i;
234 			if (DRM_COPY_TO_USER(&res->contexts[i],
235 			    &ctx, sizeof(ctx)))
236 				return EFAULT;
237 		}
238 	}
239 	res->count = DRM_RESERVED_CONTEXTS;
240 
241 	return 0;
242 }
243 
244 int drm_addctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
245 {
246 	struct drm_ctx *ctx = data;
247 
248 	ctx->handle = drm_ctxbitmap_next(dev);
249 	if (ctx->handle == DRM_KERNEL_CONTEXT) {
250 		/* Skip kernel's context and get a new one. */
251 		ctx->handle = drm_ctxbitmap_next(dev);
252 	}
253 	DRM_DEBUG("%d\n", ctx->handle);
254 	if (ctx->handle == -1) {
255 		DRM_DEBUG("Not enough free contexts.\n");
256 		/* Should this return -EBUSY instead? */
257 		return ENOMEM;
258 	}
259 
260 	if (dev->driver->context_ctor && ctx->handle != DRM_KERNEL_CONTEXT) {
261 		DRM_LOCK();
262 		dev->driver->context_ctor(dev, ctx->handle);
263 		DRM_UNLOCK();
264 	}
265 
266 	return 0;
267 }
268 
269 int drm_modctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
270 {
271 	/* This does nothing */
272 	return 0;
273 }
274 
275 int drm_getctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
276 {
277 	struct drm_ctx *ctx = data;
278 
279 	/* This is 0, because we don't handle any context flags */
280 	ctx->flags = 0;
281 
282 	return 0;
283 }
284 
285 int drm_switchctx(struct drm_device *dev, void *data,
286 		  struct drm_file *file_priv)
287 {
288 	struct drm_ctx *ctx = data;
289 
290 	DRM_DEBUG("%d\n", ctx->handle);
291 	return drm_context_switch(dev, dev->last_context, ctx->handle);
292 }
293 
294 int drm_newctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
295 {
296 	struct drm_ctx *ctx = data;
297 
298 	DRM_DEBUG("%d\n", ctx->handle);
299 	drm_context_switch_complete(dev, ctx->handle);
300 
301 	return 0;
302 }
303 
304 int drm_rmctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
305 {
306 	struct drm_ctx *ctx = data;
307 
308 	DRM_DEBUG("%d\n", ctx->handle);
309 	if (ctx->handle != DRM_KERNEL_CONTEXT) {
310 		if (dev->driver->context_dtor) {
311 			DRM_LOCK();
312 			dev->driver->context_dtor(dev, ctx->handle);
313 			DRM_UNLOCK();
314 		}
315 
316 		drm_ctxbitmap_free(dev, ctx->handle);
317 	}
318 
319 	return 0;
320 }
321