diff options
Diffstat (limited to 'drivers/gpu/drm/lib/drm_random.c')
-rw-r--r-- | drivers/gpu/drm/lib/drm_random.c | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/drivers/gpu/drm/lib/drm_random.c b/drivers/gpu/drm/lib/drm_random.c new file mode 100644 index 0000000000..31b5a3e219 --- /dev/null +++ b/drivers/gpu/drm/lib/drm_random.c @@ -0,0 +1,43 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/bitops.h> +#include <linux/kernel.h> +#include <linux/random.h> +#include <linux/slab.h> +#include <linux/types.h> + +#include "drm_random.h" + +u32 drm_prandom_u32_max_state(u32 ep_ro, struct rnd_state *state) +{ + return upper_32_bits((u64)prandom_u32_state(state) * ep_ro); +} +EXPORT_SYMBOL(drm_prandom_u32_max_state); + +void drm_random_reorder(unsigned int *order, unsigned int count, + struct rnd_state *state) +{ + unsigned int i, j; + + for (i = 0; i < count; ++i) { + BUILD_BUG_ON(sizeof(unsigned int) > sizeof(u32)); + j = drm_prandom_u32_max_state(count, state); + swap(order[i], order[j]); + } +} +EXPORT_SYMBOL(drm_random_reorder); + +unsigned int *drm_random_order(unsigned int count, struct rnd_state *state) +{ + unsigned int *order, i; + + order = kmalloc_array(count, sizeof(*order), GFP_KERNEL); + if (!order) + return order; + + for (i = 0; i < count; i++) + order[i] = i; + + drm_random_reorder(order, count, state); + return order; +} +EXPORT_SYMBOL(drm_random_order); |