[PATCH] drm/i915/wopcm: Try to use already locked WOPCM layout

[Michal Wajdeczko]

If WOPCM layout is already locked we shouldn't continue with
own partitioning as it will be likely unsuccessful. Instead
we should try to reuse what is alreay programmed.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
---
 drivers/gpu/drm/i915/intel_wopcm.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_wopcm.c b/drivers/gpu/drm/i915/intel_wopcm.c
index 2bda24200498..cd23e5a6b6be 100644
--- a/drivers/gpu/drm/i915/intel_wopcm.c
+++ b/drivers/gpu/drm/i915/intel_wopcm.c
@@ -154,6 +154,21 @@ static inline int check_hw_restriction(struct drm_i915_private *i915,
 	return err;
 }
 
+static bool __wopcm_regs_locked(struct intel_gt *gt,
+				u32 *guc_wopcm_base, u32 *guc_wopcm_size)
+{
+	u32 reg_base = intel_uncore_read(gt->uncore, DMA_GUC_WOPCM_OFFSET);
+	u32 reg_size = intel_uncore_read(gt->uncore, GUC_WOPCM_SIZE);
+
+	if (!(reg_size & GUC_WOPCM_SIZE_LOCKED) ||
+	    !(reg_base & GUC_WOPCM_OFFSET_VALID))
+		return false;
+
+	*guc_wopcm_base = reg_base & GUC_WOPCM_OFFSET_MASK;
+	*guc_wopcm_size = reg_size & GUC_WOPCM_SIZE_MASK;
+	return true;
+}
+
 /**
  * intel_wopcm_init() - Initialize the WOPCM structure.
  * @wopcm: pointer to intel_wopcm.
@@ -197,6 +212,9 @@ void intel_wopcm_init(struct intel_wopcm *wopcm)
 		return;
 	}
 
+	if (__wopcm_regs_locked(&i915->gt, &guc_wopcm_base, &guc_wopcm_size))
+		goto check;
+
 	guc_wopcm_base = ALIGN(huc_fw_size + WOPCM_RESERVED_SIZE,
 			       GUC_WOPCM_OFFSET_ALIGNMENT);
 	if ((guc_wopcm_base + ctx_rsvd) >= wopcm->size) {
@@ -219,6 +237,7 @@ void intel_wopcm_init(struct intel_wopcm *wopcm)
 		return;
 	}
 
+check:
 	err = check_hw_restriction(i915, guc_wopcm_base, guc_wopcm_size,
 				   huc_fw_size);
 	if (err)
-- 
2.19.2