[PATCH v4 04/13] drm/i915/guc: Implement response handling in send_mmio()

[Michal Wajdeczko]

We use data encoded in the status MMIO as return value from send
function, but GuC may write additional data in remaining MMIO regs.
Let's copy content of these registers to the caller provided buffer.

v2: new line (Michel)
v3: updated commit message

Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
Cc: Oscar Mateo <oscar.mateo at intel.com>
Reviewed-by: Michel Thierry <michel.thierry at intel.com> #2
---
 drivers/gpu/drm/i915/intel_guc.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_guc.c b/drivers/gpu/drm/i915/intel_guc.c
index 30ec10a..c1a8b20 100644
--- a/drivers/gpu/drm/i915/intel_guc.c
+++ b/drivers/gpu/drm/i915/intel_guc.c
@@ -364,11 +364,20 @@ int intel_guc_send_mmio(struct intel_guc *guc, const u32 *action, u32 len,
 				 " ret=%d status=0x%08X response=0x%08X\n",
 				 action[0], ret, status,
 				 I915_READ(SOFT_SCRATCH(15)));
-	} else {
-		/* Use data from the GuC response as our return value */
-		ret = INTEL_GUC_MSG_TO_DATA(status);
+		goto out;
 	}
 
+	if (response_buf) {
+		int count = min(response_buf_size, guc->send_regs.count - 1);
+
+		for (i = 0; i < count; i++)
+			response_buf[i] = I915_READ(guc_send_reg(guc, i + 1));
+	}
+
+	/* Use data from the GuC response as our return value */
+	ret = INTEL_GUC_MSG_TO_DATA(status);
+
+out:
 	intel_uncore_forcewake_put(dev_priv, guc->send_regs.fw_domains);
 	mutex_unlock(&guc->send_mutex);
 
-- 
1.9.1