1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/bitops.h> 3 #include <linux/kernel.h> 4 #include <linux/random.h> 5 #include <linux/slab.h> 6 #include <linux/types.h> 7 8 #include "drm_random.h" 9 10 u32 drm_prandom_u32_max_state(u32 ep_ro, struct rnd_state *state) 11 { 12 return upper_32_bits((u64)prandom_u32_state(state) * ep_ro); 13 } 14 EXPORT_SYMBOL(drm_prandom_u32_max_state); 15 16 void drm_random_reorder(unsigned int *order, unsigned int count, 17 struct rnd_state *state) 18 { 19 unsigned int i, j; 20 21 for (i = 0; i < count; ++i) { 22 BUILD_BUG_ON(sizeof(unsigned int) > sizeof(u32)); 23 j = drm_prandom_u32_max_state(count, state); 24 swap(order[i], order[j]); 25 } 26 } 27 EXPORT_SYMBOL(drm_random_reorder); 28 29 unsigned int *drm_random_order(unsigned int count, struct rnd_state *state) 30 { 31 unsigned int *order, i; 32 33 order = kmalloc_array(count, sizeof(*order), GFP_KERNEL); 34 if (!order) 35 return order; 36 37 for (i = 0; i < count; i++) 38 order[i] = i; 39 40 drm_random_reorder(order, count, state); 41 return order; 42 } 43 EXPORT_SYMBOL(drm_random_order); 44