LXR linux/drivers/gpu/drm/i915/selftests/i915

   1/*
   2 * Copyright © 2016 Intel Corporation
   3 *
   4 * Permission is hereby granted, free of charge, to any person obtaining a
   5 * copy of this software and associated documentation files (the "Software"),
   6 * to deal in the Software without restriction, including without limitation
   7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8 * and/or sell copies of the Software, and to permit persons to whom the
   9 * Software is furnished to do so, subject to the following conditions:
  10 *
  11 * The above copyright notice and this permission notice (including the next
  12 * paragraph) shall be included in all copies or substantial portions of the
  13 * Software.
  14 *
  15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21 * IN THE SOFTWARE.
  22 *
  23 */
  24
  25#include <linux/bitops.h>
  26#include <linux/kernel.h>
  27#include <linux/random.h>
  28#include <linux/slab.h>
  29#include <linux/types.h>
  30
  31#include "i915_random.h"
  32
  33u64 i915_prandom_u64_state(struct rnd_state *rnd)
  34{
  35        u64 x;
  36
  37        x = prandom_u32_state(rnd);
  38        x <<= 32;
  39        x |= prandom_u32_state(rnd);
  40
  41        return x;
  42}
  43
  44void i915_random_reorder(unsigned int *order, unsigned int count,
  45                         struct rnd_state *state)
  46{
  47        unsigned int i, j;
  48
  49        for (i = 0; i < count; i++) {
  50                BUILD_BUG_ON(sizeof(unsigned int) > sizeof(u32));
  51                j = i915_prandom_u32_max_state(count, state);
  52                swap(order[i], order[j]);
  53        }
  54}
  55
  56unsigned int *i915_random_order(unsigned int count, struct rnd_state *state)
  57{
  58        unsigned int *order, i;
  59
  60        order = kmalloc_array(count, sizeof(*order),
  61                              GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
  62        if (!order)
  63                return order;
  64
  65        for (i = 0; i < count; i++)
  66                order[i] = i;
  67
  68        i915_random_reorder(order, count, state);
  69        return order;
  70}
  71