From a33d42dd03352d2e9d3d2c00bfa435c7a5ebab25 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Thu, 22 Dec 2016 08:36:08 +0000 Subject: 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 Cc: Joonas Lahtinen Cc: David Herrmann Reviewed-by: Joonas Lahtinen Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/20161222083641.2691-6-chris@chris-wilson.co.uk --- drivers/gpu/drm/lib/drm_random.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 drivers/gpu/drm/lib/drm_random.h (limited to 'drivers/gpu/drm/lib/drm_random.h') diff --git a/drivers/gpu/drm/lib/drm_random.h b/drivers/gpu/drm/lib/drm_random.h new file mode 100644 index 000000000000..a78644bea7f9 --- /dev/null +++ b/drivers/gpu/drm/lib/drm_random.h @@ -0,0 +1,25 @@ +#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 + +#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__ */ -- cgit