FreeBSD/Linux Kernel Cross Reference
sys/dev/drm2/drm_context.c

     /**
      * \file drm_context.c
      * IOCTLs for generic contexts
      *
      * \author Rickard E. (Rik) Faith <faith@valinux.com>
      * \author Gareth Hughes <gareth@valinux.com>
      */
     
     /*
     * Created: Fri Nov 24 18:31:37 2000 by gareth@valinux.com
     *
     * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
     * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
     * All Rights Reserved.
     *
     * Permission is hereby granted, free of charge, to any person obtaining a
     * copy of this software and associated documentation files (the "Software"),
     * to deal in the Software without restriction, including without limitation
     * the rights to use, copy, modify, merge, publish, distribute, sublicense,
     * and/or sell copies of the Software, and to permit persons to whom the
     * Software is furnished to do so, subject to the following conditions:
     *
     * The above copyright notice and this permission notice (including the next
     * paragraph) shall be included in all copies or substantial portions of the
     * Software.
     *
     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
     * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
     * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     * OTHER DEALINGS IN THE SOFTWARE.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    /*
     * ChangeLog:
     *  2001-11-16  Torsten Duwe <duwe@caldera.de>
     *              added context constructor/destructor hooks,
     *              needed by SiS driver's memory management.
     */
    
    #include <dev/drm2/drmP.h>
    
    /******************************************************************/
    /** \name Context bitmap support */
    /*@{*/
    
    /**
     * Free a handle from the context bitmap.
     *
     * \param dev DRM device.
     * \param ctx_handle context handle.
     *
     * Clears the bit specified by \p ctx_handle in drm_device::ctx_bitmap and the entry
     * in drm_device::ctx_idr, while holding the drm_device::struct_mutex
     * lock.
     */
    void drm_ctxbitmap_free(struct drm_device * dev, int ctx_handle)
    {
            if (ctx_handle < 0 || ctx_handle >= DRM_MAX_CTXBITMAP ||
                dev->ctx_bitmap == NULL) {
                    DRM_ERROR("Attempt to free invalid context handle: %d\n",
                       ctx_handle);
                    return;
            }
    
            DRM_LOCK(dev);
            clear_bit(ctx_handle, dev->ctx_bitmap);
            dev->context_sareas[ctx_handle] = NULL;
            DRM_UNLOCK(dev);
    }
    
    /**
     * Context bitmap allocation.
     *
     * \param dev DRM device.
     * \return (non-negative) context handle on success or a negative number on failure.
     *
     * Allocate a new idr from drm_device::ctx_idr while holding the
     * drm_device::struct_mutex lock.
     */
    static int drm_ctxbitmap_next(struct drm_device * dev)
    {
            int bit;
    
            if (dev->ctx_bitmap == NULL)
                    return -1;
    
            DRM_LOCK(dev);
            bit = find_first_zero_bit(dev->ctx_bitmap, DRM_MAX_CTXBITMAP);
            if (bit >= DRM_MAX_CTXBITMAP) {
                    DRM_UNLOCK(dev);
                    return -1;
            }
    
           set_bit(bit, dev->ctx_bitmap);
           DRM_DEBUG("bit : %d\n", bit);
           if ((bit+1) > dev->max_context) {
                   struct drm_local_map **ctx_sareas;
                   int max_ctx = (bit+1);
   
                   ctx_sareas = realloc(dev->context_sareas,
                       max_ctx * sizeof(*dev->context_sareas),
                       DRM_MEM_SAREA, M_NOWAIT);
                   if (ctx_sareas == NULL) {
                           clear_bit(bit, dev->ctx_bitmap);
                           DRM_DEBUG("failed to allocate bit : %d\n", bit);
                           DRM_UNLOCK(dev);
                           return -1;
                   }
                   dev->max_context = max_ctx;
                   dev->context_sareas = ctx_sareas;
                   dev->context_sareas[bit] = NULL;
           }
           DRM_UNLOCK(dev);
           return bit;
   }
   
   /**
    * Context bitmap initialization.
    *
    * \param dev DRM device.
    *
    * Initialise the drm_device::ctx_idr
    */
   int drm_ctxbitmap_init(struct drm_device * dev)
   {
           int i;
           int temp;
   
           DRM_LOCK(dev);
           dev->ctx_bitmap = malloc(PAGE_SIZE, DRM_MEM_CTXBITMAP,
               M_NOWAIT | M_ZERO);
           if (dev->ctx_bitmap == NULL) {
                   DRM_UNLOCK(dev);
                   return ENOMEM;
           }
           dev->context_sareas = NULL;
           dev->max_context = -1;
           DRM_UNLOCK(dev);
   
           for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
                   temp = drm_ctxbitmap_next(dev);
                   DRM_DEBUG("drm_ctxbitmap_init : %d\n", temp);
           }
   
           return 0;
   }
   
   /**
    * Context bitmap cleanup.
    *
    * \param dev DRM device.
    *
    * Free all idr members using drm_ctx_sarea_free helper function
    * while holding the drm_device::struct_mutex lock.
    */
   void drm_ctxbitmap_cleanup(struct drm_device * dev)
   {
           DRM_LOCK(dev);
           if (dev->context_sareas != NULL)
                   free(dev->context_sareas, DRM_MEM_SAREA);
           free(dev->ctx_bitmap, DRM_MEM_CTXBITMAP);
           DRM_UNLOCK(dev);
   }
   
   /*@}*/
   
   /******************************************************************/
   /** \name Per Context SAREA Support */
   /*@{*/
   
   /**
    * Get per-context SAREA.
    *
    * \param inode device inode.
    * \param file_priv DRM file private.
    * \param cmd command.
    * \param arg user argument pointing to a drm_ctx_priv_map structure.
    * \return zero on success or a negative number on failure.
    *
    * Gets the map from drm_device::ctx_idr with the handle specified and
    * returns its handle.
    */
   int drm_getsareactx(struct drm_device *dev, void *data,
                       struct drm_file *file_priv)
   {
           struct drm_ctx_priv_map *request = data;
           struct drm_local_map *map;
   
           DRM_LOCK(dev);
           if (dev->max_context < 0 ||
               request->ctx_id >= (unsigned) dev->max_context) {
                   DRM_UNLOCK(dev);
                   return EINVAL;
           }
   
           map = dev->context_sareas[request->ctx_id];
           DRM_UNLOCK(dev);
   
           request->handle = (void *)map->handle;
   
           return 0;
   }
   
   /**
    * Set per-context SAREA.
    *
    * \param inode device inode.
    * \param file_priv DRM file private.
    * \param cmd command.
    * \param arg user argument pointing to a drm_ctx_priv_map structure.
    * \return zero on success or a negative number on failure.
    *
    * Searches the mapping specified in \p arg and update the entry in
    * drm_device::ctx_idr with it.
    */
   int drm_setsareactx(struct drm_device *dev, void *data,
                       struct drm_file *file_priv)
   {
           struct drm_ctx_priv_map *request = data;
           struct drm_local_map *map = NULL;
           struct drm_map_list *r_list = NULL;
   
           DRM_LOCK(dev);
           list_for_each_entry(r_list, &dev->maplist, head) {
                   if (r_list->map
                       && r_list->user_token == (unsigned long) request->handle) {
                           if (dev->max_context < 0)
                                   goto bad;
                           if (request->ctx_id >= (unsigned) dev->max_context)
                                   goto bad;
                           dev->context_sareas[request->ctx_id] = map;
                           DRM_UNLOCK(dev);
                           return 0;
                   }
           }
   
   bad:
           DRM_UNLOCK(dev);
           return EINVAL;
   }
   
   /*@}*/
   
   /******************************************************************/
   /** \name The actual DRM context handling routines */
   /*@{*/
   
   /**
    * Switch context.
    *
    * \param dev DRM device.
    * \param old old context handle.
    * \param new new context handle.
    * \return zero on success or a negative number on failure.
    *
    * Attempt to set drm_device::context_flag.
    */
   static int drm_context_switch(struct drm_device * dev, int old, int new)
   {
           if (test_and_set_bit(0, &dev->context_flag)) {
                   DRM_ERROR("Reentering -- FIXME\n");
                   return -EBUSY;
           }
   
           DRM_DEBUG("Context switch from %d to %d\n", old, new);
   
           if (new == dev->last_context) {
                   clear_bit(0, &dev->context_flag);
                   return 0;
           }
   
           return 0;
   }
   
   /**
    * Complete context switch.
    *
    * \param dev DRM device.
    * \param new new context handle.
    * \return zero on success or a negative number on failure.
    *
    * Updates drm_device::last_context and drm_device::last_switch. Verifies the
    * hardware lock is held, clears the drm_device::context_flag and wakes up
    * drm_device::context_wait.
    */
   static int drm_context_switch_complete(struct drm_device *dev,
                                          struct drm_file *file_priv, int new)
   {
           dev->last_context = new;        /* PRE/POST: This is the _only_ writer. */
           dev->last_switch = jiffies;
   
           if (!_DRM_LOCK_IS_HELD(file_priv->master->lock.hw_lock->lock)) {
                   DRM_ERROR("Lock isn't held after context switch\n");
           }
   
           /* If a context switch is ever initiated
              when the kernel holds the lock, release
              that lock here. */
           clear_bit(0, &dev->context_flag);
           wakeup(&dev->context_wait);
   
           return 0;
   }
   
   /**
    * Reserve contexts.
    *
    * \param inode device inode.
    * \param file_priv DRM file private.
    * \param cmd command.
    * \param arg user argument pointing to a drm_ctx_res structure.
    * \return zero on success or a negative number on failure.
    */
   int drm_resctx(struct drm_device *dev, void *data,
                  struct drm_file *file_priv)
   {
           struct drm_ctx_res *res = data;
           struct drm_ctx ctx;
           int i;
   
           if (res->count >= DRM_RESERVED_CONTEXTS) {
                   memset(&ctx, 0, sizeof(ctx));
                   for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
                           ctx.handle = i;
                           if (copy_to_user(&res->contexts[i], &ctx, sizeof(ctx)))
                                   return -EFAULT;
                   }
           }
           res->count = DRM_RESERVED_CONTEXTS;
   
           return 0;
   }
   
   /**
    * Add context.
    *
    * \param inode device inode.
    * \param file_priv DRM file private.
    * \param cmd command.
    * \param arg user argument pointing to a drm_ctx structure.
    * \return zero on success or a negative number on failure.
    *
    * Get a new handle for the context and copy to userspace.
    */
   int drm_addctx(struct drm_device *dev, void *data,
                  struct drm_file *file_priv)
   {
           struct drm_ctx_list *ctx_entry;
           struct drm_ctx *ctx = data;
   
           ctx->handle = drm_ctxbitmap_next(dev);
           if (ctx->handle == DRM_KERNEL_CONTEXT) {
                   /* Skip kernel's context and get a new one. */
                   ctx->handle = drm_ctxbitmap_next(dev);
           }
           DRM_DEBUG("%d\n", ctx->handle);
           if (ctx->handle == -1) {
                   DRM_DEBUG("Not enough free contexts.\n");
                   /* Should this return -EBUSY instead? */
                   return -ENOMEM;
           }
   
           ctx_entry = malloc(sizeof(*ctx_entry), DRM_MEM_CTXBITMAP, M_NOWAIT);
           if (!ctx_entry) {
                   DRM_DEBUG("out of memory\n");
                   return -ENOMEM;
           }
   
           INIT_LIST_HEAD(&ctx_entry->head);
           ctx_entry->handle = ctx->handle;
           ctx_entry->tag = file_priv;
   
           DRM_LOCK(dev);
           list_add(&ctx_entry->head, &dev->ctxlist);
           ++dev->ctx_count;
           DRM_UNLOCK(dev);
   
           return 0;
   }
   
   int drm_modctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
   {
           /* This does nothing */
           return 0;
   }
   
   /**
    * Get context.
    *
    * \param inode device inode.
    * \param file_priv DRM file private.
    * \param cmd command.
    * \param arg user argument pointing to a drm_ctx structure.
    * \return zero on success or a negative number on failure.
    */
   int drm_getctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
   {
           struct drm_ctx *ctx = data;
   
           /* This is 0, because we don't handle any context flags */
           ctx->flags = 0;
   
           return 0;
   }
   
   /**
    * Switch context.
    *
    * \param inode device inode.
    * \param file_priv DRM file private.
    * \param cmd command.
    * \param arg user argument pointing to a drm_ctx structure.
    * \return zero on success or a negative number on failure.
    *
    * Calls context_switch().
    */
   int drm_switchctx(struct drm_device *dev, void *data,
                     struct drm_file *file_priv)
   {
           struct drm_ctx *ctx = data;
   
           DRM_DEBUG("%d\n", ctx->handle);
           return drm_context_switch(dev, dev->last_context, ctx->handle);
   }
   
   /**
    * New context.
    *
    * \param inode device inode.
    * \param file_priv DRM file private.
    * \param cmd command.
    * \param arg user argument pointing to a drm_ctx structure.
    * \return zero on success or a negative number on failure.
    *
    * Calls context_switch_complete().
    */
   int drm_newctx(struct drm_device *dev, void *data,
                  struct drm_file *file_priv)
   {
           struct drm_ctx *ctx = data;
   
           DRM_DEBUG("%d\n", ctx->handle);
           drm_context_switch_complete(dev, file_priv, ctx->handle);
   
           return 0;
   }
   
   /**
    * Remove context.
    *
    * \param inode device inode.
    * \param file_priv DRM file private.
    * \param cmd command.
    * \param arg user argument pointing to a drm_ctx structure.
    * \return zero on success or a negative number on failure.
    *
    * If not the special kernel context, calls ctxbitmap_free() to free the specified context.
    */
   int drm_rmctx(struct drm_device *dev, void *data,
                 struct drm_file *file_priv)
   {
           struct drm_ctx *ctx = data;
   
           DRM_DEBUG("%d\n", ctx->handle);
           if (ctx->handle != DRM_KERNEL_CONTEXT) {
                   if (dev->driver->context_dtor)
                           dev->driver->context_dtor(dev, ctx->handle);
                   drm_ctxbitmap_free(dev, ctx->handle);
           }
   
           DRM_LOCK(dev);
           if (!list_empty(&dev->ctxlist)) {
                   struct drm_ctx_list *pos, *n;
   
                   list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
                           if (pos->handle == ctx->handle) {
                                   list_del(&pos->head);
                                   free(pos, DRM_MEM_CTXBITMAP);
                                   --dev->ctx_count;
                           }
                   }
           }
           DRM_UNLOCK(dev);
   
           return 0;
   }
   
   /*@}*/

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