diff options
Diffstat (limited to 'drivers/gpu/drm/drm_global.c')
| -rw-r--r-- | drivers/gpu/drm/drm_global.c | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_global.c b/drivers/gpu/drm/drm_global.c new file mode 100644 index 000000000..5799e2782 --- /dev/null +++ b/drivers/gpu/drm/drm_global.c @@ -0,0 +1,137 @@ +// SPDX-License-Identifier: GPL-2.0 OR MIT +/************************************************************************** + * + * Copyright 2008-2009 VMware, Inc., Palo Alto, CA., USA + * + * 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, sub license, 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 NON-INFRINGEMENT. IN NO EVENT SHALL + * THE COPYRIGHT HOLDERS, AUTHORS 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. + * + **************************************************************************/ +/* + * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com> + */ + +#include <linux/mutex.h> +#include <linux/slab.h> +#include <linux/module.h> +#include <drm/drm_global.h> + +struct drm_global_item { + struct mutex mutex; + void *object; + int refcount; +}; + +static struct drm_global_item glob[DRM_GLOBAL_NUM]; + +void drm_global_init(void) +{ + int i; + + for (i = 0; i < DRM_GLOBAL_NUM; ++i) { + struct drm_global_item *item = &glob[i]; + mutex_init(&item->mutex); + item->object = NULL; + item->refcount = 0; + } +} + +void drm_global_release(void) +{ + int i; + for (i = 0; i < DRM_GLOBAL_NUM; ++i) { + struct drm_global_item *item = &glob[i]; + BUG_ON(item->object != NULL); + BUG_ON(item->refcount != 0); + } +} + +/** + * drm_global_item_ref - Initialize and acquire reference to memory + * object + * @ref: Object for initialization + * + * This initializes a memory object, allocating memory and calling the + * .init() hook. Further calls will increase the reference count for + * that item. + * + * Returns: + * Zero on success, non-zero otherwise. + */ +int drm_global_item_ref(struct drm_global_reference *ref) +{ + int ret = 0; + struct drm_global_item *item = &glob[ref->global_type]; + + mutex_lock(&item->mutex); + if (item->refcount == 0) { + ref->object = kzalloc(ref->size, GFP_KERNEL); + if (unlikely(ref->object == NULL)) { + ret = -ENOMEM; + goto error_unlock; + } + ret = ref->init(ref); + if (unlikely(ret != 0)) + goto error_free; + + item->object = ref->object; + } else { + ref->object = item->object; + } + + ++item->refcount; + mutex_unlock(&item->mutex); + return 0; + +error_free: + kfree(ref->object); + ref->object = NULL; +error_unlock: + mutex_unlock(&item->mutex); + return ret; +} +EXPORT_SYMBOL(drm_global_item_ref); + +/** + * drm_global_item_unref - Drop reference to memory + * object + * @ref: Object being removed + * + * Drop a reference to the memory object and eventually call the + * release() hook. The allocated object should be dropped in the + * release() hook or before calling this function + * + */ + +void drm_global_item_unref(struct drm_global_reference *ref) +{ + struct drm_global_item *item = &glob[ref->global_type]; + + mutex_lock(&item->mutex); + BUG_ON(item->refcount == 0); + BUG_ON(ref->object != item->object); + if (--item->refcount == 0) { + ref->release(ref); + item->object = NULL; + } + mutex_unlock(&item->mutex); +} +EXPORT_SYMBOL(drm_global_item_unref); + |