dma-resv.h

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/*
 * Header file for reservations for dma-buf and ttm
 *
 * Copyright(C) 2011 Linaro Limited. All rights reserved.
 * Copyright (C) 2012-2013 Canonical Ltd
 * Copyright (C) 2012 Texas Instruments
 *
 * Authors:
 * Rob Clark <robdclark@gmail.com>
 * Maarten Lankhorst <maarten.lankhorst@canonical.com>
 * Thomas Hellstrom <thellstrom-at-vmware-dot-com>
 *
 * Based on bo.c which bears the following copyright notice,
 * but is dual licensed:
 *
 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
 * 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, 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.
 */
#ifndef _LINUX_RESERVATION_H
#define _LINUX_RESERVATION_H
 
#include <linux/ww_mutex.h>
#include <linux/dma-fence.h>
#include <linux/slab.h>
#include <linux/seqlock.h>
#include <linux/rcupdate.h>
 
extern struct ww_class reservation_ww_class;
 
struct dma_resv_list;
 
enum dma_resv_usage {
    DMA_RESV_USAGE_KERNEL,
 
    DMA_RESV_USAGE_WRITE,
 
    DMA_RESV_USAGE_READ,
 
    DMA_RESV_USAGE_BOOKKEEP
};
 
static inline enum dma_resv_usage dma_resv_usage_rw(bool write)
{
    /* This looks confusing at first sight, but is indeed correct.
     *
     * The rational is that new write operations needs to wait for the
     * existing read and write operations to finish.
     * But a new read operation only needs to wait for the existing write
     * operations to finish.
     */
    return write ? DMA_RESV_USAGE_READ : DMA_RESV_USAGE_WRITE;
}
 
struct dma_resv {
    struct ww_mutex lock;
 
    struct dma_resv_list __rcu *fences;
};
 
struct dma_resv_iter {
    struct dma_resv *obj;
 
    enum dma_resv_usage usage;
 
    struct dma_fence *fence;
 
    enum dma_resv_usage fence_usage;
 
    unsigned int index;
 
    struct dma_resv_list *fences;
 
    unsigned int num_fences;
 
    bool is_restarted;
};
 
struct dma_fence *dma_resv_iter_first_unlocked(struct dma_resv_iter *cursor);
struct dma_fence *dma_resv_iter_next_unlocked(struct dma_resv_iter *cursor);
struct dma_fence *dma_resv_iter_first(struct dma_resv_iter *cursor);
struct dma_fence *dma_resv_iter_next(struct dma_resv_iter *cursor);
 
static inline void dma_resv_iter_begin(struct dma_resv_iter *cursor,
                       struct dma_resv *obj,
                       enum dma_resv_usage usage)
{
    cursor->obj = obj;
    cursor->usage = usage;
    cursor->fence = NULL;
}
 
static inline void dma_resv_iter_end(struct dma_resv_iter *cursor)
{
    dma_fence_put(cursor->fence);
}
 
static inline enum dma_resv_usage
dma_resv_iter_usage(struct dma_resv_iter *cursor)
{
    return cursor->fence_usage;
}
 
static inline bool dma_resv_iter_is_restarted(struct dma_resv_iter *cursor)
{
    return cursor->is_restarted;
}
 
#define dma_resv_for_each_fence_unlocked(cursor, fence)         \
    for (fence = dma_resv_iter_first_unlocked(cursor);      \
         fence; fence = dma_resv_iter_next_unlocked(cursor))
 
#define dma_resv_for_each_fence(cursor, obj, usage, fence)  \
    for (dma_resv_iter_begin(cursor, obj, usage),   \
         fence = dma_resv_iter_first(cursor); fence;    \
         fence = dma_resv_iter_next(cursor))
 
#define dma_resv_held(obj) lockdep_is_held(&(obj)->lock.base)
#define dma_resv_assert_held(obj) lockdep_assert_held(&(obj)->lock.base)
 
#ifdef CONFIG_DEBUG_MUTEXES
void dma_resv_reset_max_fences(struct dma_resv *obj);
#else
static inline void dma_resv_reset_max_fences(struct dma_resv *obj) {}
#endif
 
static inline int dma_resv_lock(struct dma_resv *obj,
                struct ww_acquire_ctx *ctx)
{
    return ww_mutex_lock(&obj->lock, ctx);
}
 
static inline int dma_resv_lock_interruptible(struct dma_resv *obj,
                          struct ww_acquire_ctx *ctx)
{
    return ww_mutex_lock_interruptible(&obj->lock, ctx);
}
 
static inline void dma_resv_lock_slow(struct dma_resv *obj,
                      struct ww_acquire_ctx *ctx)
{
    ww_mutex_lock_slow(&obj->lock, ctx);
}
 
static inline int dma_resv_lock_slow_interruptible(struct dma_resv *obj,
                           struct ww_acquire_ctx *ctx)
{
    return ww_mutex_lock_slow_interruptible(&obj->lock, ctx);
}
 
static inline bool __must_check dma_resv_trylock(struct dma_resv *obj)
{
    return ww_mutex_trylock(&obj->lock, NULL);
}
 
static inline bool dma_resv_is_locked(struct dma_resv *obj)
{
    return ww_mutex_is_locked(&obj->lock);
}
 
static inline struct ww_acquire_ctx *dma_resv_locking_ctx(struct dma_resv *obj)
{
    return READ_ONCE(obj->lock.ctx);
}
 
static inline void dma_resv_unlock(struct dma_resv *obj)
{
    dma_resv_reset_max_fences(obj);
    ww_mutex_unlock(&obj->lock);
}
 
void dma_resv_init(struct dma_resv *obj);
void dma_resv_fini(struct dma_resv *obj);
int dma_resv_reserve_fences(struct dma_resv *obj, unsigned int num_fences);
void dma_resv_add_fence(struct dma_resv *obj, struct dma_fence *fence,
            enum dma_resv_usage usage);
void dma_resv_replace_fences(struct dma_resv *obj, uint64_t context,
                 struct dma_fence *fence,
                 enum dma_resv_usage usage);
int dma_resv_get_fences(struct dma_resv *obj, enum dma_resv_usage usage,
            unsigned int *num_fences, struct dma_fence ***fences);
int dma_resv_get_singleton(struct dma_resv *obj, enum dma_resv_usage usage,
               struct dma_fence **fence);
int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src);
long dma_resv_wait_timeout(struct dma_resv *obj, enum dma_resv_usage usage,
               bool intr, unsigned long timeout);
void dma_resv_set_deadline(struct dma_resv *obj, enum dma_resv_usage usage,
               ktime_t deadline);
bool dma_resv_test_signaled(struct dma_resv *obj, enum dma_resv_usage usage);
void dma_resv_describe(struct dma_resv *obj, struct seq_file *seq);
 
#endif /* _LINUX_RESERVATION_H */