[Intel-gfx] [PATCH 1/9] drm/i915: Add automated testing support for Displayport compliance testing

[Todd Previte]

Add the skeleton framework for supporting automation for Displayport compliance
testing. This patch adds the necessary framework for the source device to
appropriately respond to test automation requests from a sink device.

V2:
- Addressed previous mailing list feedback
- Fixed compilation issue (struct members declared in a later patch)
- Updated debug messages to be more accurate
- Added status checks for the DPCD read/write calls
- Removed excess comments and debug messages
- Fixed debug message compilation warnings
- Fixed compilation issue with missing variables
- Updated link training autotest to ACK

V3:
- Fixed the checks on the DPCD return code to be <= 0
  rather than != 0
- Removed extraneous assignment of a NAK return code in the
  DPCD read failure case
- Changed the return in the DPCD read failure case to a goto
  to the exit point where the status code is written to the sink
- Removed FAUX test case since it's deprecated now
- Removed the compliance flag assignment in handle_test_request

Signed-off-by: Todd Previte <tprevite at gmail.com>
---
 drivers/gpu/drm/i915/intel_dp.c  | 67 +++++++++++++++++++++++++++++++++++++---
 drivers/gpu/drm/i915/intel_drv.h |  4 +++
 2 files changed, 67 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index eea9e36..25ffa7d 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -3746,11 +3746,70 @@ intel_dp_get_sink_irq_esi(struct intel_dp *intel_dp, u8 *sink_irq_vector)
 	return true;
 }
 
-static void
-intel_dp_handle_test_request(struct intel_dp *intel_dp)
+static uint8_t intel_dp_autotest_link_training(struct intel_dp *intel_dp)
+{
+	uint8_t test_result = DP_TEST_ACK;
+	return test_result;
+}
+
+static uint8_t intel_dp_autotest_video_pattern(struct intel_dp *intel_dp)
+{
+	uint8_t test_result = DP_TEST_NAK;
+	return test_result;
+}
+
+static uint8_t intel_dp_autotest_edid(struct intel_dp *intel_dp)
+{
+	uint8_t test_result = DP_TEST_NAK;
+	return test_result;
+}
+
+static uint8_t intel_dp_autotest_phy_pattern(struct intel_dp *intel_dp)
+{
+	uint8_t test_result = DP_TEST_NAK;
+	return test_result;
+}
+
+static void intel_dp_handle_test_request(struct intel_dp *intel_dp)
 {
-	/* NAK by default */
-	drm_dp_dpcd_writeb(&intel_dp->aux, DP_TEST_RESPONSE, DP_TEST_NAK);
+	uint8_t response = DP_TEST_NAK;
+	uint8_t rxdata = 0;
+	int status = 0;
+
+	status = drm_dp_dpcd_read(&intel_dp->aux, DP_TEST_REQUEST, &rxdata, 1);
+	if (status <= 0) {
+		DRM_DEBUG_KMS("Could not read test request from sink\n");
+		goto update_status;
+	}
+
+	switch (rxdata) {
+	case DP_TEST_LINK_TRAINING:
+		DRM_DEBUG_KMS("LINK_TRAINING test requested\n");
+		response = intel_dp_autotest_link_training(intel_dp);
+		break;
+	case DP_TEST_LINK_VIDEO_PATTERN:
+		DRM_DEBUG_KMS("TEST_PATTERN test requested\n");
+		response = intel_dp_autotest_video_pattern(intel_dp);
+		break;
+	case DP_TEST_LINK_EDID_READ:
+		DRM_DEBUG_KMS("EDID test requested\n");
+		response = intel_dp_autotest_edid(intel_dp);
+		break;
+	case DP_TEST_LINK_PHY_TEST_PATTERN:
+		DRM_DEBUG_KMS("PHY_PATTERN test requested\n");
+		response = intel_dp_autotest_phy_pattern(intel_dp);
+		break;
+	default:
+		DRM_DEBUG_KMS("Invalid test request '%02x'\n", rxdata);
+		break;
+	}
+
+update_status:
+	status = drm_dp_dpcd_write(&intel_dp->aux,
+				   DP_TEST_RESPONSE,
+				   &response, 1);
+	if (status <= 0)
+		DRM_DEBUG_KMS("Could not write test response to sink\n");
 }
 
 static int
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index eef79cc..74b30c1 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -647,6 +647,10 @@ struct intel_dp {
 				     bool has_aux_irq,
 				     int send_bytes,
 				     uint32_t aux_clock_divider);
+
+	/* Displayport compliance testing */
+	unsigned long compliance_test_data;
+	bool compliance_testing_active;
 };
 
 struct intel_digital_port {
-- 
1.9.1