[Intel-gfx] [PATCH v2 2/4] drm/i915/guc: Wait for ucode DMA transfer completion

[Michal Wajdeczko]

We silently assumed that DMA transfer will be completed
within assumed timeout and thus we were waiting only at
last step for GuC to become ready. Add intermediate wait
to catch unexpected delays in DMA transfer.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Sagar Arun Kamble <sagar.a.kamble at intel.com>
---
 drivers/gpu/drm/i915/intel_guc_fw.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_guc_fw.c b/drivers/gpu/drm/i915/intel_guc_fw.c
index c4f4526..74a61fe 100644
--- a/drivers/gpu/drm/i915/intel_guc_fw.c
+++ b/drivers/gpu/drm/i915/intel_guc_fw.c
@@ -160,6 +160,8 @@ static int guc_xfer_ucode(struct intel_guc *guc, struct i915_vma *vma)
 	struct drm_i915_private *dev_priv = guc_to_i915(guc);
 	struct intel_uc_fw *guc_fw = &guc->fw;
 	unsigned long offset;
+	u32 status;
+	int ret;
 
 	/*
 	 * The header plus uCode will be copied to WOPCM via DMA, excluding any
@@ -182,7 +184,12 @@ static int guc_xfer_ucode(struct intel_guc *guc, struct i915_vma *vma)
 	/* Finally start the DMA */
 	I915_WRITE(DMA_CTRL, _MASKED_BIT_ENABLE(UOS_MOVE | START_DMA));
 
-	return 0;
+	/* Wait for DMA to finish */
+	ret = __intel_wait_for_register_fw(dev_priv, DMA_CTRL, START_DMA, 0,
+					   2, 100, &status);
+	DRM_DEBUG_DRIVER("GuC DMA status %#x\n", status);
+
+	return ret;
 }
 
 /*
-- 
2.7.4