[PATCH 2/2] drm/i915: Add a link training test

From: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
To: intel-gfx@lists.freedesktop.org
Cc: Ander Conselvan de Oliveira
	<ander.conselvan.de.oliveira@intel.com>,
	thomas.wood@intel.com
Subject: [PATCH 2/2] drm/i915: Add a link training test
Date: Tue, 15 Sep 2015 16:11:36 +0300	[thread overview]
Message-ID: <1442322696-31286-2-git-send-email-ander.conselvan.de.oliveira@intel.com> (raw)
In-Reply-To: <1442322696-31286-1-git-send-email-ander.conselvan.de.oliveira@intel.com>

---
 drivers/gpu/drm/i915/Kconfig                       |  10 +
 drivers/gpu/drm/i915/Makefile                      |   5 +
 drivers/gpu/drm/i915/i915_drv.c                    |   2 +
 drivers/gpu/drm/i915/i915_drv.h                    |   8 +
 .../drm/i915/tests/test_intel_dp_link_training.c   | 467 +++++++++++++++++++++
 drivers/gpu/drm/i915/tests/tests.c                 |   7 +
 drivers/gpu/drm/i915/tests/tests.h                 |   6 +
 7 files changed, 505 insertions(+)
 create mode 100644 drivers/gpu/drm/i915/tests/test_intel_dp_link_training.c
 create mode 100644 drivers/gpu/drm/i915/tests/tests.c
 create mode 100644 drivers/gpu/drm/i915/tests/tests.h

diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig
index 051eab3..fb42a9f 100644
--- a/drivers/gpu/drm/i915/Kconfig
+++ b/drivers/gpu/drm/i915/Kconfig
@@ -47,3 +47,13 @@ config DRM_I915_PRELIMINARY_HW_SUPPORT
 	  option changes the default for that module option.
 
 	  If in doubt, say "N".
+
+config DRM_I915_UNIT_TESTS
+	bool "Enable execution of unit tests on module load"
+	depends on DRM_I915
+	default n
+	help
+	  Choose this option to run a series of unit tests when the i915
+	  module is loaded.
+
+	  If in doubt, say "N".
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 0851de07..bd7e283 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -97,6 +97,11 @@ i915-y += i915_vgpu.o
 # legacy horrors
 i915-y += i915_dma.o
 
+# Unit tests
+i915-$(CONFIG_DRM_I915_UNIT_TESTS) += \
+	tests/tests.o \
+	tests/test_intel_dp_link_training.o
+
 obj-$(CONFIG_DRM_I915)  += i915.o
 
 CFLAGS_i915_trace_points.o := -I$(src)
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index bdec64c..2494667 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1707,6 +1707,8 @@ static int __init i915_init(void)
 {
 	driver.num_ioctls = i915_max_ioctl;
 
+	i915_run_unit_tests();
+
 	/*
 	 * Enable KMS by default, unless explicitly overriden by
 	 * either the i915.modeset prarameter or by the
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 3bf8a9b..39c58d1 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -3502,4 +3502,12 @@ static inline void i915_trace_irq_get(struct intel_engine_cs *ring,
 		i915_gem_request_assign(&ring->trace_irq_req, req);
 }
 
+#ifdef CONFIG_DRM_I915_UNIT_TESTS
+void i915_run_unit_tests(void);
+#else
+static inline void i915_run_unit_tests(void)
+{
+}
+#endif
+
 #endif
diff --git a/drivers/gpu/drm/i915/tests/test_intel_dp_link_training.c b/drivers/gpu/drm/i915/tests/test_intel_dp_link_training.c
new file mode 100644
index 0000000..ab5de74
--- /dev/null
+++ b/drivers/gpu/drm/i915/tests/test_intel_dp_link_training.c
@@ -0,0 +1,467 @@
+/*
+ * Copyright © 2015 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ *    Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
+ *
+ */
+
+#include "../intel_drv.h"
+
+#define assert(x)	WARN_ON(!(x))
+
+struct sink_device {
+	ssize_t (*dpcd_write)(struct sink_device *sink, unsigned int offset,
+			      void *buffer, size_t size);
+	bool (*get_link_status)(struct sink_device *sink,
+				uint8_t link_status[DP_LINK_STATUS_SIZE]);
+
+	struct {
+		bool lane_count_and_bw_set;
+		bool training_pattern_1_set;
+		bool started_with_non_zero_levels;
+		bool cr_done;
+		bool channel_eq_done;
+
+		uint8_t dpcd[0x3000];
+	} data;
+};
+
+/* Fake sink device implementation */
+
+static uint8_t
+sink_device_lane_count(struct sink_device *sink)
+{
+	return sink->data.dpcd[DP_LANE_COUNT_SET];
+}
+
+static uint8_t
+sink_device_get_training_pattern(struct sink_device *sink)
+{
+	return sink->data.dpcd[DP_TRAINING_PATTERN_SET] & DP_TRAINING_PATTERN_MASK;
+}
+
+static uint8_t
+sink_device_get_voltage_swing(struct sink_device *sink, int lane)
+{
+	return sink->data.dpcd[DP_TRAINING_LANE0_SET + lane] &
+		DP_TRAIN_VOLTAGE_SWING_MASK;
+}
+
+static uint8_t
+sink_device_get_pre_emphasis_level(struct sink_device *sink, int lane)
+{
+	return (sink->data.dpcd[DP_TRAINING_LANE0_SET + lane] &
+		 DP_TRAIN_PRE_EMPHASIS_MASK) >> DP_TRAIN_PRE_EMPHASIS_SHIFT;
+}
+
+static void
+sink_device_check_lane_count_and_bw(struct sink_device *sink)
+{
+	if (sink->data.lane_count_and_bw_set)
+		return;
+
+	assert(sink->data.dpcd[DP_TRAINING_PATTERN_SET] == 0);
+
+	if (sink->data.dpcd[DP_LINK_BW_SET] != 0 &&
+	    sink->data.dpcd[DP_LANE_COUNT_SET] != 0)
+		sink->data.lane_count_and_bw_set = true;
+}
+
+static void
+sink_device_check_pattern_1_set(struct sink_device *sink)
+{
+	int lane;
+
+	if (!sink->data.lane_count_and_bw_set ||
+	    sink->data.training_pattern_1_set)
+		return;
+
+	assert(sink_device_get_training_pattern(sink) <= DP_TRAINING_PATTERN_1);
+
+	if (sink_device_get_training_pattern(sink) != DP_TRAINING_PATTERN_1)
+		return;
+
+	assert(sink->data.dpcd[DP_LINK_BW_SET] == DP_LINK_BW_1_62 ||
+	       sink->data.dpcd[DP_LINK_BW_SET] == DP_LINK_BW_2_7);
+
+	assert(sink->data.dpcd[DP_LANE_COUNT_SET] == 1 ||
+		   sink->data.dpcd[DP_LANE_COUNT_SET] == 2 ||
+		   sink->data.dpcd[DP_LANE_COUNT_SET] == 4);
+
+	for (lane = 0; lane < sink_device_lane_count(sink); lane++) {
+		if (sink_device_get_voltage_swing(sink, lane) != DP_TRAIN_VOLTAGE_SWING_LEVEL_0 ||
+		    sink_device_get_pre_emphasis_level(sink, lane) != DP_TRAIN_PRE_EMPH_LEVEL_0)
+			sink->data.started_with_non_zero_levels = true;
+	}
+
+	sink->data.training_pattern_1_set = true;
+}
+
+static void
+sink_device_check_pattern_2_set(struct sink_device *sink)
+{
+	if (!sink->data.cr_done)
+		return;
+
+	assert(sink_device_get_training_pattern(sink) == DP_TRAINING_PATTERN_2);
+}
+
+static void
+sink_device_check_pattern_disable(struct sink_device *sink)
+{
+	if (!sink->data.cr_done || ! sink->data.channel_eq_done)
+		return;
+
+	assert(sink_device_get_training_pattern(sink) == DP_TRAINING_PATTERN_DISABLE);
+}
+
+static ssize_t
+sink_device_dpcd_write(struct sink_device *sink, unsigned int offset,
+		       void *buffer, size_t size)
+{
+	memcpy(sink->data.dpcd + offset, buffer, size);
+
+	sink_device_check_lane_count_and_bw(sink);
+
+	if (!sink->data.cr_done)
+		sink_device_check_pattern_1_set(sink);
+	else if (!sink->data.channel_eq_done)
+		sink_device_check_pattern_2_set(sink);
+	else
+		sink_device_check_pattern_disable(sink);
+
+	return size;
+}
+
+static bool
+sink_device_max_voltage_reached(struct sink_device *sink, int lane)
+{
+	return (sink->data.dpcd[DP_TRAINING_LANE0_SET + lane] & DP_TRAIN_MAX_SWING_REACHED) ==
+		DP_TRAIN_MAX_SWING_REACHED;
+}
+
+static bool
+sink_device_max_pre_emphasis_reached(struct sink_device *sink, int lane)
+{
+	return (sink->data.dpcd[DP_TRAINING_LANE0_SET + lane] & DP_TRAIN_MAX_PRE_EMPHASIS_REACHED) ==
+		DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;
+}
+
+static void
+sink_device_set_adjust_voltage(struct sink_device *sink,
+			       int lane, uint8_t level)
+{
+	int shift = DP_ADJUST_VOLTAGE_SWING_LANE1_SHIFT * (lane & 1);
+
+	sink->data.dpcd[DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1)] &=
+		~(DP_ADJUST_VOLTAGE_SWING_LANE0_MASK << shift);
+	sink->data.dpcd[DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1)] |=
+		level << shift;
+}
+
+static void
+sink_device_set_adjust_pre_emphasis(struct sink_device *sink,
+				    int lane, uint8_t level)
+{
+	int shift = DP_ADJUST_VOLTAGE_SWING_LANE1_SHIFT * (lane & 1);
+
+	sink->data.dpcd[DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1)] &=
+		~(DP_ADJUST_PRE_EMPHASIS_LANE0_MASK << shift);
+	sink->data.dpcd[DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1)] |=
+		level << (DP_ADJUST_PRE_EMPHASIS_LANE0_SHIFT + shift);
+}
+
+static bool
+sink_device_request_higher_voltage_swing(struct sink_device *sink)
+{
+	bool max_reached = false;
+	int lane;
+
+	for (lane = 0; lane < sink_device_lane_count(sink); lane++) {
+		if (sink_device_max_voltage_reached(sink, lane)) {
+			max_reached = true;
+			break;
+		}
+	}
+
+	if (max_reached)
+		return false;
+
+	for (lane = 0; lane < sink_device_lane_count(sink); lane++) {
+		uint8_t new_voltage =
+			sink_device_get_voltage_swing(sink, lane) + 1;
+
+		sink_device_set_adjust_voltage(sink, lane, new_voltage);
+	}
+
+	return true;
+}
+
+static bool
+sink_device_request_higher_pre_emphasis(struct sink_device *sink)
+{
+	bool max_reached = false;
+	int lane;
+
+	for (lane = 0; lane < sink_device_lane_count(sink); lane++) {
+		if (sink_device_max_pre_emphasis_reached(sink, lane)) {
+			max_reached = true;
+			break;
+		}
+	}
+
+	if (max_reached)
+		return false;
+
+	for (lane = 0; lane < sink_device_lane_count(sink); lane++) {
+		uint8_t new_pre_emphasis =
+			sink_device_get_pre_emphasis_level(sink, lane) + 1;
+
+		sink_device_set_adjust_pre_emphasis(sink, lane, new_pre_emphasis);
+	}
+
+	return true;
+}
+
+static void
+sink_device_mark_cr_done(struct sink_device *sink)
+{
+	int lane;
+
+	for (lane = 0; lane < sink_device_lane_count(sink); lane++)
+		sink->data.dpcd[DP_LANE0_1_STATUS + (lane >> 1)] |=
+			DP_LANE_CR_DONE << (4 * (lane & 1));
+
+	sink->data.cr_done = true;
+}
+
+static void
+sink_device_mark_channel_eq_done(struct sink_device *sink)
+{
+	int lane;
+
+	for (lane = 0; lane < sink_device_lane_count(sink); lane++) {
+		uint8_t mask = (DP_LANE_CHANNEL_EQ_DONE | DP_LANE_SYMBOL_LOCKED);
+		sink->data.dpcd[DP_LANE0_1_STATUS + (lane >> 1)] |=
+			mask << (4 * (lane & 1));
+	}
+
+	sink->data.dpcd[DP_LANE_ALIGN_STATUS_UPDATED] |= DP_INTERLANE_ALIGN_DONE;
+
+	sink->data.channel_eq_done = true;
+}
+
+static bool
+sink_device_get_link_status(struct sink_device *sink,
+			    uint8_t link_status[DP_LINK_STATUS_SIZE])
+{
+	if (!sink->data.cr_done) {
+		if (!sink_device_request_higher_voltage_swing(sink))
+			sink_device_mark_cr_done(sink);
+	} else if (!sink->data.channel_eq_done) {
+		if (!sink_device_request_higher_pre_emphasis(sink))
+			sink_device_mark_channel_eq_done(sink);
+	}
+
+	memcpy(link_status, sink->data.dpcd + DP_LANE0_1_STATUS,
+	       DP_LINK_STATUS_SIZE);
+
+	return true;
+}
+
+static void
+sink_device_reset(struct sink_device *sink, int lanes, uint8_t link_bw)
+{
+	memset(&sink->data, 0, sizeof sink->data);
+	sink->data.dpcd[DP_MAX_LINK_RATE] = link_bw;
+	sink->data.dpcd[DP_MAX_LANE_COUNT] = lanes;
+}
+
+static struct sink_device simple_sink = {
+	.get_link_status = sink_device_get_link_status,
+	.dpcd_write = sink_device_dpcd_write,
+};
+
+/* Glue code */
+
+struct test_intel_dp {
+	struct intel_dp dp;
+	struct sink_device *sink;
+	uint8_t link_bw;
+
+	uint8_t max_voltage;
+	uint8_t max_pre_emphasis;
+};
+
+static struct test_intel_dp *
+to_test_intel_dp(struct intel_dp *dp)
+{
+	return container_of(dp, struct test_intel_dp, dp);
+}
+
+void test_dp_set_idle_link_train(struct intel_dp *intel_dp)
+{
+}
+
+bool
+test_dp_get_link_status(struct intel_dp *intel_dp, uint8_t link_status[DP_LINK_STATUS_SIZE])
+{
+	struct sink_device *sink = to_test_intel_dp(intel_dp)->sink;
+	return sink->get_link_status(sink, link_status);
+}
+
+void
+test_dp_update_signal_levels(struct intel_dp *intel_dp)
+{
+}
+
+void test_dp_compute_rate(struct intel_dp *intel_dp, int port_clock,
+			   uint8_t *link_bw, uint8_t *rate_select)
+{
+	*link_bw = to_test_intel_dp(intel_dp)->link_bw;
+	*rate_select = 0;
+}
+
+void
+test_dp_program_link_training_pattern(struct intel_dp *intel_dp,
+				       uint8_t dp_train_pat)
+{
+}
+
+uint8_t
+test_dp_voltage_max(struct intel_dp *intel_dp)
+{
+	return to_test_intel_dp(intel_dp)->max_voltage <<
+		DP_TRAIN_VOLTAGE_SWING_SHIFT;
+}
+
+uint8_t
+test_dp_pre_emphasis_max(struct intel_dp *intel_dp, uint8_t voltage_swing)
+{
+	return to_test_intel_dp(intel_dp)->max_pre_emphasis <<
+		DP_TRAIN_PRE_EMPHASIS_SHIFT;
+}
+
+ssize_t test_dp_dpcd_write(struct intel_dp *intel_dp, unsigned int offset,
+			   void *buffer, size_t size)
+{
+	struct sink_device *sink = to_test_intel_dp(intel_dp)->sink;
+	return sink->dpcd_write(sink, offset, buffer, size);
+}
+
+static bool test_dp_source_supports_hbr2(struct intel_dp *dp)
+{
+	return false;
+}
+
+/* --- */
+
+static struct test_intel_dp test_dp;
+
+static void
+do_test(struct sink_device *sink, int lanes, uint8_t link_bw,
+	     uint8_t max_voltage, uint8_t max_pre_emphasis)
+{
+	int lane;
+
+	memset(&test_dp, 0, sizeof test_dp);
+	test_dp.dp.lane_count = lanes;
+	test_dp.link_bw = link_bw;
+	test_dp.sink = sink;
+	test_dp.max_voltage =
+		max_voltage >> DP_TRAIN_VOLTAGE_SWING_SHIFT;
+	test_dp.max_pre_emphasis =
+		max_pre_emphasis >> DP_TRAIN_PRE_EMPHASIS_SHIFT;
+
+	test_dp.dp.get_link_status = test_dp_get_link_status;
+	test_dp.dp.set_idle_link_train = test_dp_set_idle_link_train;
+	test_dp.dp.update_signal_levels = test_dp_update_signal_levels;
+	test_dp.dp.compute_rate = test_dp_compute_rate;
+	test_dp.dp.program_link_training_pattern =
+		test_dp_program_link_training_pattern;
+	test_dp.dp.voltage_max = test_dp_voltage_max;
+	test_dp.dp.pre_emphasis_max = test_dp_pre_emphasis_max;
+	test_dp.dp.dpcd_write = test_dp_dpcd_write;
+	test_dp.dp.source_supports_hbr2 = test_dp_source_supports_hbr2;
+
+	sink_device_reset(sink, lanes, link_bw);
+
+	intel_dp_start_link_train(&test_dp.dp);
+	intel_dp_stop_link_train(&test_dp.dp);
+
+	assert(sink->data.cr_done);
+	assert(sink->data.channel_eq_done);
+
+	for (lane = 0; lane < test_dp.dp.lane_count; lane++) {
+		uint8_t cur_v = sink_device_get_voltage_swing(sink, lane);
+		uint8_t cur_p = sink_device_get_pre_emphasis_level(sink, lane);
+
+		assert(cur_v == test_dp.max_voltage);
+		assert(cur_p == test_dp.max_pre_emphasis);
+	}
+}
+
+int test_lanes[] = {
+	1, 2, 4,
+};
+
+uint8_t test_bw[] = {
+	DP_LINK_BW_1_62,
+	DP_LINK_BW_2_7,
+};
+
+uint8_t test_max_voltage[] = {
+	DP_TRAIN_VOLTAGE_SWING_LEVEL_0,
+	DP_TRAIN_VOLTAGE_SWING_LEVEL_1,
+	DP_TRAIN_VOLTAGE_SWING_LEVEL_2,
+	DP_TRAIN_VOLTAGE_SWING_LEVEL_3,
+};
+
+uint8_t test_max_pre_emphasis[] = {
+	DP_TRAIN_PRE_EMPH_LEVEL_0,
+	DP_TRAIN_PRE_EMPH_LEVEL_1,
+	DP_TRAIN_PRE_EMPH_LEVEL_2,
+	DP_TRAIN_PRE_EMPH_LEVEL_3,
+};
+
+void
+run_link_training_tests(void)
+{
+	int lane, bw, voltage, emph;
+
+	for (lane = 0; lane < ARRAY_SIZE(test_lanes); lane++)
+	for (bw = 0; bw < ARRAY_SIZE(test_bw); bw++)
+	for (voltage = 0; voltage < ARRAY_SIZE(test_max_voltage); voltage++)
+	for (emph = 0; emph < ARRAY_SIZE(test_max_pre_emphasis); emph++) {
+		DRM_DEBUG_KMS("l%d-bw%d-v%d-pe%d",
+			      test_lanes[lane],
+			      test_bw[bw],
+			      test_max_voltage[voltage],
+			      test_max_pre_emphasis[emph]);
+		do_test(&simple_sink,
+			test_lanes[lane],
+			test_bw[bw],
+			test_max_voltage[voltage],
+			test_max_pre_emphasis[emph]);
+	}
+}
diff --git a/drivers/gpu/drm/i915/tests/tests.c b/drivers/gpu/drm/i915/tests/tests.c
new file mode 100644
index 0000000..8e4344a
--- /dev/null
+++ b/drivers/gpu/drm/i915/tests/tests.c
@@ -0,0 +1,7 @@
+#include "tests.h"
+
+void
+i915_run_unit_tests(void)
+{
+	run_link_training_tests();
+}
diff --git a/drivers/gpu/drm/i915/tests/tests.h b/drivers/gpu/drm/i915/tests/tests.h
new file mode 100644
index 0000000..400b523
--- /dev/null
+++ b/drivers/gpu/drm/i915/tests/tests.h
@@ -0,0 +1,6 @@
+#ifndef _I915_TESTS_H_
+#define _I915_TESTS_H_
+
+void run_link_training_tests(void);
+
+#endif /* _I915_TESTS_H_ */
-- 
2.4.3

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