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    Subject[PATCH v10 12/15] drm/msm: Add deadline based boost support
    Date
    From: Rob Clark <robdclark@chromium.org>

    Track the nearest deadline on a fence timeline and set a timer to expire
    shortly before to trigger boost if the fence has not yet been signaled.

    v2: rebase

    Signed-off-by: Rob Clark <robdclark@chromium.org>
    ---
    drivers/gpu/drm/msm/msm_fence.c | 74 +++++++++++++++++++++++++++++++++
    drivers/gpu/drm/msm/msm_fence.h | 20 +++++++++
    2 files changed, 94 insertions(+)

    diff --git a/drivers/gpu/drm/msm/msm_fence.c b/drivers/gpu/drm/msm/msm_fence.c
    index 56641408ea74..51b461f32103 100644
    --- a/drivers/gpu/drm/msm/msm_fence.c
    +++ b/drivers/gpu/drm/msm/msm_fence.c
    @@ -8,6 +8,35 @@

    #include "msm_drv.h"
    #include "msm_fence.h"
    +#include "msm_gpu.h"
    +
    +static struct msm_gpu *fctx2gpu(struct msm_fence_context *fctx)
    +{
    + struct msm_drm_private *priv = fctx->dev->dev_private;
    + return priv->gpu;
    +}
    +
    +static enum hrtimer_restart deadline_timer(struct hrtimer *t)
    +{
    + struct msm_fence_context *fctx = container_of(t,
    + struct msm_fence_context, deadline_timer);
    +
    + kthread_queue_work(fctx2gpu(fctx)->worker, &fctx->deadline_work);
    +
    + return HRTIMER_NORESTART;
    +}
    +
    +static void deadline_work(struct kthread_work *work)
    +{
    + struct msm_fence_context *fctx = container_of(work,
    + struct msm_fence_context, deadline_work);
    +
    + /* If deadline fence has already passed, nothing to do: */
    + if (msm_fence_completed(fctx, fctx->next_deadline_fence))
    + return;
    +
    + msm_devfreq_boost(fctx2gpu(fctx), 2);
    +}


    struct msm_fence_context *
    @@ -36,6 +65,13 @@ msm_fence_context_alloc(struct drm_device *dev, volatile uint32_t *fenceptr,
    fctx->completed_fence = fctx->last_fence;
    *fctx->fenceptr = fctx->last_fence;

    + hrtimer_init(&fctx->deadline_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
    + fctx->deadline_timer.function = deadline_timer;
    +
    + kthread_init_work(&fctx->deadline_work, deadline_work);
    +
    + fctx->next_deadline = ktime_get();
    +
    return fctx;
    }

    @@ -62,6 +98,8 @@ void msm_update_fence(struct msm_fence_context *fctx, uint32_t fence)
    spin_lock_irqsave(&fctx->spinlock, flags);
    if (fence_after(fence, fctx->completed_fence))
    fctx->completed_fence = fence;
    + if (msm_fence_completed(fctx, fctx->next_deadline_fence))
    + hrtimer_cancel(&fctx->deadline_timer);
    spin_unlock_irqrestore(&fctx->spinlock, flags);
    }

    @@ -92,10 +130,46 @@ static bool msm_fence_signaled(struct dma_fence *fence)
    return msm_fence_completed(f->fctx, f->base.seqno);
    }

    +static void msm_fence_set_deadline(struct dma_fence *fence, ktime_t deadline)
    +{
    + struct msm_fence *f = to_msm_fence(fence);
    + struct msm_fence_context *fctx = f->fctx;
    + unsigned long flags;
    + ktime_t now;
    +
    + spin_lock_irqsave(&fctx->spinlock, flags);
    + now = ktime_get();
    +
    + if (ktime_after(now, fctx->next_deadline) ||
    + ktime_before(deadline, fctx->next_deadline)) {
    + fctx->next_deadline = deadline;
    + fctx->next_deadline_fence =
    + max(fctx->next_deadline_fence, (uint32_t)fence->seqno);
    +
    + /*
    + * Set timer to trigger boost 3ms before deadline, or
    + * if we are already less than 3ms before the deadline
    + * schedule boost work immediately.
    + */
    + deadline = ktime_sub(deadline, ms_to_ktime(3));
    +
    + if (ktime_after(now, deadline)) {
    + kthread_queue_work(fctx2gpu(fctx)->worker,
    + &fctx->deadline_work);
    + } else {
    + hrtimer_start(&fctx->deadline_timer, deadline,
    + HRTIMER_MODE_ABS);
    + }
    + }
    +
    + spin_unlock_irqrestore(&fctx->spinlock, flags);
    +}
    +
    static const struct dma_fence_ops msm_fence_ops = {
    .get_driver_name = msm_fence_get_driver_name,
    .get_timeline_name = msm_fence_get_timeline_name,
    .signaled = msm_fence_signaled,
    + .set_deadline = msm_fence_set_deadline,
    };

    struct dma_fence *
    diff --git a/drivers/gpu/drm/msm/msm_fence.h b/drivers/gpu/drm/msm/msm_fence.h
    index 7f1798c54cd1..cdaebfb94f5c 100644
    --- a/drivers/gpu/drm/msm/msm_fence.h
    +++ b/drivers/gpu/drm/msm/msm_fence.h
    @@ -52,6 +52,26 @@ struct msm_fence_context {
    volatile uint32_t *fenceptr;

    spinlock_t spinlock;
    +
    + /*
    + * TODO this doesn't really deal with multiple deadlines, like
    + * if userspace got multiple frames ahead.. OTOH atomic updates
    + * don't queue, so maybe that is ok
    + */
    +
    + /** next_deadline: Time of next deadline */
    + ktime_t next_deadline;
    +
    + /**
    + * next_deadline_fence:
    + *
    + * Fence value for next pending deadline. The deadline timer is
    + * canceled when this fence is signaled.
    + */
    + uint32_t next_deadline_fence;
    +
    + struct hrtimer deadline_timer;
    + struct kthread_work deadline_work;
    };

    struct msm_fence_context * msm_fence_context_alloc(struct drm_device *dev,
    --
    2.39.2
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