[PATCH V2] drm/i915: Implement Displayport automated testing

[Todd Previte <tprevite@gmail.com>]

This initial patch adds support for automated testing of the source device
to the i915 driver. Most of this patch is infrastructure for the tests;
follow up patches will add support for the individual tests with updates
to ACK the tests that are supported (or NAK if the test
fails/is unsupported).

Signed-off-by: Todd Previte <tprevite@gmail.com>
---
 drivers/gpu/drm/i915/intel_dp.c | 75 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 72 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 9770160..1f97a1c 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2730,11 +2730,80 @@ intel_dp_get_sink_irq(struct intel_dp *intel_dp, u8 *sink_irq_vector)
 	return true;
 }
 
+/* Automated test function hook - description forthcoming */
+static bool
+intel_dp_autotest_link_training(struct intel_dp *intel_dp)
+{
+	bool test_result = false;
+	return test_result;
+}
+
+/* Automated test function hook - description forthcoming */
+static bool
+intel_dp_autotest_video_pattern(struct intel_dp *intel_dp)
+{
+	bool test_result = false;
+	return test_result;
+}
+
+/* Automated test function hook - description forthcoming */
+static bool
+intel_dp_autotest_edid(struct intel_dp *intel_dp)
+{
+	bool test_result = false;
+	return test_result;
+}
+
+/* Automated test function hook - description forthcoming */
+static bool
+intel_dp_autotest_phy_pattern(struct intel_dp *intel_dp)
+{
+	bool test_result = false;
+	return test_result;
+}
+
 static void
 intel_dp_handle_test_request(struct intel_dp *intel_dp)
-{
-	/* NAK by default */
-	intel_dp_aux_native_write_1(intel_dp, DP_TEST_RESPONSE, DP_TEST_NAK);
+{	
+	uint8_t response = DP_TEST_NAK;
+	bool result = false;
+	uint8_t rxdata = 0;
+
+	printk(KERN_DEBUG "Displayport: Recvd automated test request\n");
+	/* Read DP_TEST_REQUEST register to identify the requested test */
+	intel_dp_aux_native_read_retry(intel_dp, DP_TEST_REQUEST, &rxdata, 1);
+	/* Determine which test has been requested */
+	switch (rxdata) {
+		/* ACK/NAK response based on the success or failure of the specified
+		   automated test function. Unimplemented tests will NAK as will those
+		   that are unsupported. */
+		case DP_TEST_LINK_TRAINING:
+			printk(KERN_DEBUG "Displayport: Executing LINK_TRAINING request\n");
+			result = intel_dp_autotest_link_training(intel_dp);
+			break;
+		case DP_TEST_LINK_PATTERN:
+			printk(KERN_DEBUG "Displayport: Executing TEST_PATTERN request\n");
+			result = intel_dp_autotest_video_pattern(intel_dp);
+			break;
+		case DP_TEST_LINK_EDID_READ:
+			printk(KERN_DEBUG "Displayport: Executing EDID request\n");
+			result = intel_dp_autotest_edid(intel_dp);
+			break;
+		case DP_TEST_LINK_PHY_TEST_PATTERN:
+			printk(KERN_DEBUG "Displayport: Executing PHY_PATTERN request\n");
+			result = intel_dp_autotest_phy_pattern(intel_dp);
+			break;
+		/* Unsupported test case or something went wrong */
+		default:
+			/* Log error here for unhandled test request */
+			printk(KERN_DEBUG "Displayport: Error - unhandled automated test type\n");
+			break;
+	}
+	/* Check for a valid test execution */
+	if (result == true)
+		response = DP_TEST_ACK;
+	/* Send ACK/NAK based on action taken above */
+	intel_dp_aux_native_write_1(intel_dp, DP_TEST_RESPONSE, response);
 }
 
 /*
-- 
1.8.1.2