/*
|
* 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"
|
#include "i915_utils.h"
|
|
u64 i915_prandom_u64_state(struct rnd_state *rnd)
|
{
|
u64 x;
|
|
x = prandom_u32_state(rnd);
|
x <<= 32;
|
x |= prandom_u32_state(rnd);
|
|
return x;
|
}
|
|
void i915_prandom_shuffle(void *arr, size_t elsz, size_t count,
|
struct rnd_state *state)
|
{
|
char stack[128];
|
|
if (WARN_ON(elsz > sizeof(stack) || count > U32_MAX))
|
return;
|
|
if (!elsz || !count)
|
return;
|
|
/* Fisher-Yates shuffle courtesy of Knuth */
|
while (--count) {
|
size_t swp;
|
|
swp = i915_prandom_u32_max_state(count + 1, state);
|
if (swp == count)
|
continue;
|
|
memcpy(stack, arr + count * elsz, elsz);
|
memcpy(arr + count * elsz, arr + swp * elsz, elsz);
|
memcpy(arr + swp * elsz, stack, elsz);
|
}
|
}
|
|
void i915_random_reorder(unsigned int *order, unsigned int count,
|
struct rnd_state *state)
|
{
|
i915_prandom_shuffle(order, sizeof(*order), count, state);
|
}
|
|
unsigned int *i915_random_order(unsigned int count, struct rnd_state *state)
|
{
|
unsigned int *order, i;
|
|
order = kmalloc_array(count, sizeof(*order),
|
GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
|
if (!order)
|
return order;
|
|
for (i = 0; i < count; i++)
|
order[i] = i;
|
|
i915_random_reorder(order, count, state);
|
return order;
|
}
|
|
u64 igt_random_offset(struct rnd_state *state,
|
u64 start, u64 end,
|
u64 len, u64 align)
|
{
|
u64 range, addr;
|
|
BUG_ON(range_overflows(start, len, end));
|
BUG_ON(round_up(start, align) > round_down(end - len, align));
|
|
range = round_down(end - len, align) - round_up(start, align);
|
if (range) {
|
addr = i915_prandom_u64_state(state);
|
div64_u64_rem(addr, range, &addr);
|
start += addr;
|
}
|
|
return round_up(start, align);
|
}
|
