/* SPDX-License-Identifier: GPL-2.0 OR MIT */

#ifndef __DRM_EXEC_H__
#define __DRM_EXEC_H__

#include <linux/compiler.h>
#include <linux/ww_mutex.h>

#define DRM_EXEC_INTERRUPTIBLE_WAIT     BIT(0)
#define DRM_EXEC_IGNORE_DUPLICATES      BIT(1)

struct drm_gem_object;

/**
 * struct drm_exec - Execution context
 */
struct drm_exec {
        /**
         * @flags: Flags to control locking behavior
         */
        u32                     flags;

        /**
         * @ticket: WW ticket used for acquiring locks
         */
        struct ww_acquire_ctx   ticket;

        /**
         * @num_objects: number of objects locked
         */
        unsigned int            num_objects;

        /**
         * @max_objects: maximum objects in array
         */
        unsigned int            max_objects;

        /**
         * @objects: array of the locked objects
         */
        struct drm_gem_object   **objects;

        /**
         * @contended: contended GEM object we backed off for
         */
        struct drm_gem_object   *contended;

        /**
         * @prelocked: already locked GEM object due to contention
         */
        struct drm_gem_object *prelocked;
};

/**
 * drm_exec_obj() - Return the object for a give drm_exec index
 * @exec: Pointer to the drm_exec context
 * @index: The index.
 *
 * Return: Pointer to the locked object corresponding to @index if
 * index is within the number of locked objects. NULL otherwise.
 */
static inline struct drm_gem_object *
drm_exec_obj(struct drm_exec *exec, unsigned long index)
{
        return index < exec->num_objects ? exec->objects[index] : NULL;
}

/**
 * drm_exec_for_each_locked_object - iterate over all the locked objects
 * @exec: drm_exec object
 * @index: unsigned long index for the iteration
 * @obj: the current GEM object
 *
 * Iterate over all the locked GEM objects inside the drm_exec object.
 */
#define drm_exec_for_each_locked_object(exec, index, obj)               \
        for ((index) = 0; ((obj) = drm_exec_obj(exec, index)); ++(index))

/**
 * drm_exec_for_each_locked_object_reverse - iterate over all the locked
 * objects in reverse locking order
 * @exec: drm_exec object
 * @index: unsigned long index for the iteration
 * @obj: the current GEM object
 *
 * Iterate over all the locked GEM objects inside the drm_exec object in
 * reverse locking order. Note that @index may go below zero and wrap,
 * but that will be caught by drm_exec_obj(), returning a NULL object.
 */
#define drm_exec_for_each_locked_object_reverse(exec, index, obj)       \
        for ((index) = (exec)->num_objects - 1;                         \
             ((obj) = drm_exec_obj(exec, index)); --(index))

/**
 * drm_exec_until_all_locked - loop until all GEM objects are locked
 * @exec: drm_exec object
 *
 * Core functionality of the drm_exec object. Loops until all GEM objects are
 * locked and no more contention exists. At the beginning of the loop it is
 * guaranteed that no GEM object is locked.
 *
 * Since labels can't be defined local to the loops body we use a jump pointer
 * to make sure that the retry is only used from within the loops body.
 */
#define drm_exec_until_all_locked(exec)                                 \
__PASTE(__drm_exec_, __LINE__):                                         \
        for (void *__drm_exec_retry_ptr; ({                             \
                __drm_exec_retry_ptr = &&__PASTE(__drm_exec_, __LINE__);\
                (void)__drm_exec_retry_ptr;                             \
                drm_exec_cleanup(exec);                                 \
        });)

/**
 * drm_exec_retry_on_contention - restart the loop to grap all locks
 * @exec: drm_exec object
 *
 * Control flow helper to continue when a contention was detected and we need to
 * clean up and re-start the loop to prepare all GEM objects.
 */
#define drm_exec_retry_on_contention(exec)                      \
        do {                                                    \
                if (unlikely(drm_exec_is_contended(exec)))      \
                        goto *__drm_exec_retry_ptr;             \
        } while (0)

/**
 * drm_exec_is_contended - check for contention
 * @exec: drm_exec object
 *
 * Returns true if the drm_exec object has run into some contention while
 * locking a GEM object and needs to clean up.
 */
static inline bool drm_exec_is_contended(struct drm_exec *exec)
{
        return !!exec->contended;
}

void drm_exec_init(struct drm_exec *exec, u32 flags, unsigned nr);
void drm_exec_fini(struct drm_exec *exec);
bool drm_exec_cleanup(struct drm_exec *exec);
int drm_exec_lock_obj(struct drm_exec *exec, struct drm_gem_object *obj);
void drm_exec_unlock_obj(struct drm_exec *exec, struct drm_gem_object *obj);
int drm_exec_prepare_obj(struct drm_exec *exec, struct drm_gem_object *obj,
                         unsigned int num_fences);
int drm_exec_prepare_array(struct drm_exec *exec,
                           struct drm_gem_object **objects,
                           unsigned int num_objects,
                           unsigned int num_fences);

#endif