64 lines
2.0 KiB
C
64 lines
2.0 KiB
C
/*
|
|
* 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.
|
|
*
|
|
*/
|
|
|
|
#include <linux/bitops.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/random.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/types.h>
|
|
|
|
#include "i915_random.h"
|
|
|
|
static inline u32 i915_prandom_u32_max_state(u32 ep_ro, struct rnd_state *state)
|
|
{
|
|
return upper_32_bits((u64)prandom_u32_state(state) * ep_ro);
|
|
}
|
|
|
|
void i915_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 = i915_prandom_u32_max_state(count, state);
|
|
swap(order[i], order[j]);
|
|
}
|
|
}
|
|
|
|
unsigned int *i915_random_order(unsigned int count, struct rnd_state *state)
|
|
{
|
|
unsigned int *order, i;
|
|
|
|
order = kmalloc_array(count, sizeof(*order), GFP_TEMPORARY);
|
|
if (!order)
|
|
return order;
|
|
|
|
for (i = 0; i < count; i++)
|
|
order[i] = i;
|
|
|
|
i915_random_reorder(order, count, state);
|
|
return order;
|
|
}
|