diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/gpu/drm/v3d/v3d_drv.h | 41 |
1 files changed, 28 insertions, 13 deletions
diff --git a/drivers/gpu/drm/v3d/v3d_drv.h b/drivers/gpu/drm/v3d/v3d_drv.h index 9a35c555ec52..ac2603334587 100644 --- a/drivers/gpu/drm/v3d/v3d_drv.h +++ b/drivers/gpu/drm/v3d/v3d_drv.h @@ -254,27 +254,42 @@ struct v3d_csd_job { }; /** - * _wait_for - magic (register) wait macro + * __wait_for - magic wait macro * - * Does the right thing for modeset paths when run under kdgb or similar atomic - * contexts. Note that it's important that we check the condition again after - * having timed out, since the timeout could be due to preemption or similar and - * we've never had a chance to check the condition before the timeout. + * Macro to help avoid open coding check/wait/timeout patterns. Note that it's + * important that we check the condition again after having timed out, since the + * timeout could be due to preemption or similar and we've never had a chance to + * check the condition before the timeout. */ -#define wait_for(COND, MS) ({ \ - unsigned long timeout__ = jiffies + msecs_to_jiffies(MS) + 1; \ - int ret__ = 0; \ - while (!(COND)) { \ - if (time_after(jiffies, timeout__)) { \ - if (!(COND)) \ - ret__ = -ETIMEDOUT; \ +#define __wait_for(OP, COND, US, Wmin, Wmax) ({ \ + const ktime_t end__ = ktime_add_ns(ktime_get_raw(), 1000ll * (US)); \ + long wait__ = (Wmin); /* recommended min for usleep is 10 us */ \ + int ret__; \ + might_sleep(); \ + for (;;) { \ + const bool expired__ = ktime_after(ktime_get_raw(), end__); \ + OP; \ + /* Guarantee COND check prior to timeout */ \ + barrier(); \ + if (COND) { \ + ret__ = 0; \ break; \ } \ - msleep(1); \ + if (expired__) { \ + ret__ = -ETIMEDOUT; \ + break; \ + } \ + usleep_range(wait__, wait__ * 2); \ + if (wait__ < (Wmax)) \ + wait__ <<= 1; \ } \ ret__; \ }) +#define _wait_for(COND, US, Wmin, Wmax) __wait_for(, (COND), (US), (Wmin), \ + (Wmax)) +#define wait_for(COND, MS) _wait_for((COND), (MS) * 1000, 10, 1000) + static inline unsigned long nsecs_to_jiffies_timeout(const u64 n) { /* nsecs_to_jiffies64() does not guard against overflow */ |