linux-stable/drivers/gpu/drm/lib/drm_random.h
Chris Wilson a33d42dd03 drm: Add a simple generator of random permutations
When testing, we want a random but yet reproducible order in which to
process elements. Here we create an array which is a random (using the
Tausworthe PRNG) permutation of the order in which to execute.

Note these are simple helpers intended to be merged upstream in lib/

v2: Tidier code by David Herrmann
v3: Add reminder that this code is intended to be temporary, with at
least the bulk of the prandom changes going to lib/

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161222083641.2691-6-chris@chris-wilson.co.uk
2016-12-27 12:34:00 +01:00

25 lines
680 B
C

#ifndef __DRM_RANDOM_H__
#define __DRM_RANDOM_H__
/* This is a temporary home for a couple of utility functions that should
* be transposed to lib/ at the earliest convenience.
*/
#include <linux/random.h>
#define DRM_RND_STATE_INITIALIZER(seed__) ({ \
struct rnd_state state__; \
prandom_seed_state(&state__, (seed__)); \
state__; \
})
#define DRM_RND_STATE(name__, seed__) \
struct rnd_state name__ = DRM_RND_STATE_INITIALIZER(seed__)
unsigned int *drm_random_order(unsigned int count,
struct rnd_state *state);
void drm_random_reorder(unsigned int *order,
unsigned int count,
struct rnd_state *state);
#endif /* !__DRM_RANDOM_H__ */