[PATCH] 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 | 108 +++++++++++++++++++++++++++++++++++++++-
 include/drm/drm_dp_helper.h     |   3 +-
 2 files changed, 108 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 9770160..a042d59 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -64,6 +64,26 @@ static const struct dp_link_dpll vlv_dpll[] = {
 		{ .p1 = 2, .p2 = 2, .n = 1, .m1 = 2, .m2 = 27 } }
 };
 
+/******************************************************************************
+********            Displayport automated testing                      ********
+******************************************************************************/
+/* Automated testing function - link training */
+static bool
+intel_dp_autotest_link_training(struct intel_dp *intel_dp);
+/* Automated testing function - video test pattern */
+static bool
+intel_dp_autotest_video_pattern(struct intel_dp *intel_dp);
+/* Automated testing function - EDID read */
+static bool
+intel_dp_autotest_edid(struct intel_dp *intel_dp);
+/* Automated testing function - PHY pattern */
+static bool
+intel_dp_autotest_phy_pattern(struct intel_dp *intel_dp);
+/* Automated testing function - faux pattern */
+static bool
+intel_dp_autotest_faux_pattern(struct intel_dp *intel_dp);
+/*****************************************************************************/
+
 /**
  * is_edp - is the given port attached to an eDP panel (either CPU or PCH)
  * @intel_dp: DP struct
@@ -2732,9 +2752,93 @@ intel_dp_get_sink_irq(struct intel_dp *intel_dp, u8 *sink_irq_vector)
 
 static void
 intel_dp_handle_test_request(struct intel_dp *intel_dp)
+{	
+	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) {
+		/* Supported tests handled below */
+		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_VIDEO_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;
+		case DP_TEST_LINK_FAUX_TEST_PATTERN:
+			printk(KERN_DEBUG "Displayport: Executing FAUX_PATTERN request \n");
+			result = intel_dp_autotest_faux_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);
+}
+
+/* Automated testing function - link training */
+static bool
+intel_dp_autotest_link_training(struct intel_dp *intel_dp)
+{
+	/* Automated test function hook */
+	bool test_result = false;
+	return test_result;
+}
+
+/* Automated testing function - video test pattern */
+static bool
+intel_dp_autotest_video_pattern(struct intel_dp *intel_dp)
+{
+	/* Automated test function hook */
+	bool test_result = false;
+	return test_result;
+}
+
+/* Automated testing function - EDID read */
+static bool
+intel_dp_autotest_edid(struct intel_dp *intel_dp)
+{
+	/* Automated test function hook */
+	bool test_result = false;
+	return test_result;
+}
+
+/* Automated testing function - PHY pattern */
+static bool
+intel_dp_autotest_phy_pattern(struct intel_dp *intel_dp)
+{
+	/* Automated test function hook */
+	bool test_result = false;
+	return test_result;
+}
+
+/* Automated testing function - faux pattern */
+static bool
+intel_dp_autotest_faux_pattern(struct intel_dp *intel_dp)
 {
-	/* NAK by default */
-	intel_dp_aux_native_write_1(intel_dp, DP_TEST_RESPONSE, DP_TEST_NAK);
+	/* Automated test function hook */
+	bool test_result = false;
+	return test_result;
 }
 
 /*
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index ae8dbfb..9fa544b 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -266,9 +266,10 @@
 
 #define DP_TEST_REQUEST			    0x218
 # define DP_TEST_LINK_TRAINING		    (1 << 0)
-# define DP_TEST_LINK_PATTERN		    (1 << 1)
+# define DP_TEST_LINK_VIDEO_PATTERN	    (1 << 1)
 # define DP_TEST_LINK_EDID_READ		    (1 << 2)
 # define DP_TEST_LINK_PHY_TEST_PATTERN	    (1 << 3) /* DPCD >= 1.1 */
+# define DP_TEST_LINK_FAUX_TEST_PATTERN	    (1 << 4) /* DPCD >= 1.2 */
 
 #define DP_TEST_LINK_RATE		    0x219
 # define DP_LINK_RATE_162		    (0x6)
-- 
1.8.1.2