linux_kernel/drivers/gpu/drm/i915/selftests/i915_random.h

/*
 * Copyright © 2016 Intel Corporation
 *
 * 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
 * THE AUTHORS OR COPYRIGHT HOLDERS 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 __I915_SELFTESTS_RANDOM_H__
#define __I915_SELFTESTS_RANDOM_H__

#include <linux/random.h>

#include "../i915_selftest.h"

#define I915_RND_STATE_INITIALIZER(x) ({				\
	struct rnd_state state__;					\
	prandom_seed_state(&state__, (x));				\
	state__;							\
})

#define I915_RND_STATE(name__) \
	struct rnd_state name__ = I915_RND_STATE_INITIALIZER(i915_selftest.random_seed)

#define I915_RND_SUBSTATE(name__, parent__) \
	struct rnd_state name__ = I915_RND_STATE_INITIALIZER(prandom_u32_state(&(parent__)))

u64 i915_prandom_u64_state(struct rnd_state *rnd);

static inline u32 i915_prandom_u32_max_state(u32 ep_ro, struct rnd_state *state)
{
	return upper_32_bits(mul_u32_u32(prandom_u32_state(state), ep_ro));
}

unsigned int *i915_random_order(unsigned int count,
				struct rnd_state *state);
void i915_random_reorder(unsigned int *order,
			 unsigned int count,
			 struct rnd_state *state);

#endif /* !__I915_SELFTESTS_RANDOM_H__ */