drm/v3d: Add support for compute shader dispatch.

The compute shader dispatch interface is pretty simple -- just pass in
the regs that userspace has passed us, with no CLs to run.  However,
with no CL to run it means that we need to do manual cache flushing of
the L2 after the HW execution completes (for SSBO, atomic, and
image_load_store writes that are the output of compute shaders).

This doesn't yet expose the L2 cache's ability to have a region of the
address space not write back to memory (which could be used for
shared_var storage).

So far, the Mesa side has been tested on V3D v4.2 simpenrose (passing
the ES31 tests), and on the kernel side on 7278 (failing atomic
compswap tests in a way that doesn't reproduce on simpenrose).

v2: Fix excessive allocation for the clean_job (reported by Dan
    Carpenter).  Keep refs on jobs until clean_job is finished, to
    avoid spurious MMU errors if the output BOs are freed by userspace
    before L2 cleaning is finished.

Signed-off-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20190416225856.20264-4-eric@anholt.net
Acked-by: Rob Clark <robdclark@gmail.com>

1 files changed, 13 insertions, 3 deletions

diff --git a/drivers/gpu/drm/v3d/v3d_irq.c b/drivers/gpu/drm/v3d/v3d_irq.c
index ce373ffd6380..fac3c542860b 100644
--- a/drivers/gpu/drm/v3d/v3d_irq.c
+++ b/drivers/gpu/drm/v3d/v3d_irq.c
@@ -4,9 +4,9 @@
 /**
  * DOC: Interrupt management for the V3D engine
  *
- * When we take a bin, render, or TFU done interrupt, we need to
- * signal the fence for that job so that the scheduler can queue up
- * the next one and unblock any waiters.
+ * When we take a bin, render, TFU done, or CSD done interrupt, we
+ * need to signal the fence for that job so that the scheduler can
+ * queue up the next one and unblock any waiters.
  *
  * When we take the binner out of memory interrupt, we need to
  * allocate some new memory and pass it to the binner so that the
@@ -20,6 +20,7 @@
 #define V3D_CORE_IRQS ((u32)(V3D_INT_OUTOMEM |	\
 			     V3D_INT_FLDONE |	\
 			     V3D_INT_FRDONE |	\
+			     V3D_INT_CSDDONE |	\
 			     V3D_INT_GMPV))
 
 #define V3D_HUB_IRQS ((u32)(V3D_HUB_INT_MMU_WRV |	\
@@ -112,6 +113,15 @@ v3d_irq(int irq, void *arg)
 		status = IRQ_HANDLED;
 	}
 
+	if (intsts & V3D_INT_CSDDONE) {
+		struct v3d_fence *fence =
+			to_v3d_fence(v3d->csd_job->base.irq_fence);
+
+		trace_v3d_csd_irq(&v3d->drm, fence->seqno);
+		dma_fence_signal(&fence->base);
+		status = IRQ_HANDLED;
+	}
+
 	/* We shouldn't be triggering these if we have GMP in
 	 * always-allowed mode.
 	 */