[PATCH 5/5] drm/i915: Add support for DP Video pattern compliance tests

[Manasi Navare]

The intel_dp_autotest_video_pattern() function gets invoked through the
compliance test handler on a HPD short pulse if the test type is
set to DP_TEST_VIDEO_PATTERN. This performs the DPCD registers
reads to read the requested test pattern, video pattern resolution,
frame rate and bits per color value. The results of this analysis
are handed off to userspace so that the userspace app can set the
video pattern mode appropriately for the test result/response.

The compliance_test_active flag is set at the end of the individual
test handling functions. This is so that the kernel-side operations
can be completed without the risk of interruption from the userspace
app that is polling on that flag.

Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: Daniel Vetter <daniel.vetter at intel.com>
Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c | 14 +++++++-
 drivers/gpu/drm/i915/intel_dp.c     | 68 +++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_drv.h    |  9 +++++
 3 files changed, 90 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 3799a12..b048a0e 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -4545,7 +4545,19 @@ static int i915_displayport_test_data_show(struct seq_file *m, void *data)
 		if (connector->status == connector_status_connected &&
 		    connector->encoder != NULL) {
 			intel_dp = enc_to_intel_dp(connector->encoder);
-			seq_printf(m, "%lx", intel_dp->compliance_test_data);
+			if (intel_dp->compliance_test_type ==
+			    DP_TEST_LINK_EDID_READ)
+				seq_printf(m, "%lx",
+					   intel_dp->compliance_test_data);
+			else if (intel_dp->compliance_test_type ==
+				 DP_TEST_LINK_VIDEO_PATTERN) {
+				seq_printf(m, "hdisplay: %d\n",
+					   intel_dp->test_data.hdisplay);
+				seq_printf(m, "vdisplay: %d\n",
+					   intel_dp->test_data.vdisplay);
+				seq_printf(m, "bpc: %u\n",
+					   intel_dp->test_data.bpc);
+			}
 		} else
 			seq_puts(m, "0");
 	}
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index f93e130..784f86e 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -28,8 +28,10 @@
 #include <linux/i2c.h>
 #include <linux/slab.h>
 #include <linux/export.h>
+#include <linux/types.h>
 #include <linux/notifier.h>
 #include <linux/reboot.h>
+#include <asm/byteorder.h>
 #include <drm/drmP.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc.h>
@@ -3868,7 +3870,73 @@ static uint8_t intel_dp_autotest_link_training(struct intel_dp *intel_dp)
 static uint8_t intel_dp_autotest_video_pattern(struct intel_dp *intel_dp)
 {
 	uint8_t test_result = DP_TEST_NAK;
+	uint8_t test_pattern;
+	uint16_t test_misc;
+	__be16 h_width, v_height;
+	int status = 0;
+
+	/* Read the TEST_PATTERN (DP CTS 3.1.5) */
+	status = drm_dp_dpcd_read(&intel_dp->aux, DP_TEST_PATTERN,
+				  &test_pattern, 1);
+	if (status <= 0) {
+		DRM_DEBUG_KMS("Could not read test pattern from "
+			      "reference sink\n");
+		return 0;
+	}
+	if (test_pattern != DP_COLOR_RAMP)
+		return test_result;
+	intel_dp->test_data.video_pattern = test_pattern;
+
+	status = drm_dp_dpcd_read(&intel_dp->aux, DP_TEST_H_WIDTH,
+				  &h_width, 2);
+	if (status <= 0) {
+		DRM_DEBUG_KMS("Could not read H Width from "
+			      "reference sink\n");
+		return 0;
+	}
+	intel_dp->test_data.hdisplay = be16_to_cpu(h_width);
+
+	status = drm_dp_dpcd_read(&intel_dp->aux, DP_TEST_V_HEIGHT,
+				  &v_height, 2);
+	if (status <= 0) {
+		DRM_DEBUG_KMS("Could not read V Height from "
+			      "reference sink\n");
+		return 0;
+	}
+	intel_dp->test_data.vdisplay = be16_to_cpu(v_height);
+
+	status = drm_dp_dpcd_read(&intel_dp->aux, DP_TEST_MISC,
+				  &test_misc, 1);
+	if (status <= 0) {
+		DRM_DEBUG_KMS("Could not read TEST MISC from "
+			      "reference sink\n");
+		return 0;
+	}
+	if (((test_misc & DP_TEST_COLOR_FORMAT_MASK) >> DP_TEST_MISC_BIT_1) !=
+	    DP_VIDEO_PATTERN_RGB_FORMAT)
+		return test_result;
+	if (((test_misc & DP_TEST_DYNAMIC_RANGE_MASK) >> DP_TEST_MISC_BIT_3) !=
+	    DP_VIDEO_PATTERN_VESA)
+		return test_result;
+	switch ((test_misc & DP_TEST_BIT_DEPTH_MASK) >> DP_TEST_MISC_BIT_5) {
+	case 0:
+		intel_dp->compliance_force_bpc = 6;
+		intel_dp->test_data.bpc = 6;
+		break;
+	case 1:
+		intel_dp->compliance_force_bpc = 8;
+		intel_dp->test_data.bpc = 8;
+		break;
+	default:
+		return test_result;
+	}
+	/* Set test active flag here so userspace doesn't interrupt things */
+	intel_dp->compliance_test_active = 1;
+
+	test_result = DP_TEST_ACK;
+
 	return test_result;
+
 }
 
 static uint8_t intel_dp_autotest_edid(struct intel_dp *intel_dp)
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 3eb428e..ff4431e 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -880,6 +880,12 @@ struct intel_dp_desc {
 	u8 sw_minor_rev;
 } __packed;
 
+struct compliance_test_data {
+	uint8_t video_pattern;
+	uint16_t hdisplay, vdisplay;
+	uint8_t bpc;
+};
+
 struct intel_dp {
 	i915_reg_t output_reg;
 	i915_reg_t aux_ch_ctl_reg;
@@ -961,6 +967,9 @@ struct intel_dp {
 	u8 compliance_test_lane_count;
 	u8 compliance_test_link_rate;
 	unsigned long compliance_force_bpc; /* 0 for default or bpc to use */
+	struct compliance_test_data test_data;   /* a structure to hold all dp
+						  * compliance test data
+						  */
 };
 
 struct intel_lspcon {
-- 
1.9.1