diff options
| author | Chris Wilson <chris@chris-wilson.co.uk> | 2019-10-02 15:24:30 +0300 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2019-10-02 17:30:44 +0300 |
| commit | dfe324f34c53af095bfe54b322e1a338421a6b0e (patch) | |
| tree | 639ee1e19db8928a78e87ebfe106a09bf8f95169 /drivers/gpu/drm/i915/selftests/i915_random.c | |
| parent | 006e570128f413759b9df64b51bae79903679c9b (diff) | |
| download | linux-dfe324f34c53af095bfe54b322e1a338421a6b0e.tar.xz | |
drm/i915/selftests: Extract random_offset() for use with a prng
For selftests, we desire repeatability and so prefer using a prng with
known seed over true randomness. Extract random_offset() as a selftest
utility that can take the prng state.
Suggested-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191002122430.23205-1-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers/gpu/drm/i915/selftests/i915_random.c')
| -rw-r--r-- | drivers/gpu/drm/i915/selftests/i915_random.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/selftests/i915_random.c b/drivers/gpu/drm/i915/selftests/i915_random.c index 716a3f19f030..abdfadcf626b 100644 --- a/drivers/gpu/drm/i915/selftests/i915_random.c +++ b/drivers/gpu/drm/i915/selftests/i915_random.c @@ -29,6 +29,7 @@ #include <linux/types.h> #include "i915_random.h" +#include "i915_utils.h" u64 i915_prandom_u64_state(struct rnd_state *rnd) { @@ -87,3 +88,22 @@ unsigned int *i915_random_order(unsigned int count, struct rnd_state *state) 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); +} |