zephyr: tests: Test host command EC_CMD_GET_NEXT_EVENT in `mkbp_event.c`

Tests the above host command by adding a simulated event to the keyboard
FIFO and retrieving it via the host command.

BRANCH=None
BUG=b:245531291
TEST=./twister

Signed-off-by: Tristan Honscheid <honscheid@google.com>
Change-Id: I16a1a07e5aa56b95f6e118926b531b09baab992e
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3891205
Reviewed-by: Jeremy Bettis <jbettis@chromium.org>
Code-Coverage: Zoss <zoss-cl-coverage@prod.google.com>
Commit-Queue: Jeremy Bettis <jbettis@chromium.org>

2 files changed, 103 insertions, 1 deletions

diff --git a/zephyr/test/drivers/keyboard_scan/CMakeLists.txt b/zephyr/test/drivers/keyboard_scan/CMakeLists.txt
index bef34cd276..dc57dbe259 100644
--- a/zephyr/test/drivers/keyboard_scan/CMakeLists.txt
+++ b/zephyr/test/drivers/keyboard_scan/CMakeLists.txt
@@ -2,4 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-target_sources(app PRIVATE src/keyboard_scan.c)
+target_sources(app PRIVATE
+  src/keyboard_scan.c
+  src/mkbp_event.c
+)
diff --git a/zephyr/test/drivers/keyboard_scan/src/mkbp_event.c b/zephyr/test/drivers/keyboard_scan/src/mkbp_event.c
new file mode 100644
index 0000000000..40fd4ff457
--- /dev/null
+++ b/zephyr/test/drivers/keyboard_scan/src/mkbp_event.c
@@ -0,0 +1,99 @@
+/* Copyright 2022 The ChromiumOS Authors.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#include <zephyr/ztest.h>
+#include <zephyr/drivers/emul.h>
+#include <zephyr/drivers/gpio.h>
+#include <zephyr/drivers/gpio/gpio_emul.h>
+#include <zephyr/fff.h>
+#include <emul/emul_kb_raw.h>
+
+#include "console.h"
+#include "host_command.h"
+#include "mkbp_event.h"
+#include "test/drivers/test_mocks.h"
+#include "test/drivers/test_state.h"
+
+ZTEST(mkbp_event, host_command_get_events__empty)
+{
+	/* Issue a host command to get the next event (from any source) */
+	uint16_t ret;
+	struct ec_response_get_next_event response;
+	struct host_cmd_handler_args args =
+		BUILD_HOST_COMMAND_RESPONSE(EC_CMD_GET_NEXT_EVENT, 0, response);
+
+	ret = host_command_process(&args);
+	zassert_equal(EC_RES_UNAVAILABLE, ret,
+		      "Expected EC_RES_UNAVAILABLE but got %d", ret);
+}
+
+ZTEST(mkbp_event, host_command_get_events__get_event)
+{
+	/* Dispatch a fake keyboard event and ensure it gets returned by the
+	 * host command.
+	 */
+	int ret;
+
+	struct ec_response_get_next_event expected_event = {
+		.event_type = EC_MKBP_EVENT_KEY_MATRIX,
+		.data.key_matrix = {
+			/* Arbitrary key matrix data (uint8_t[13]) */
+			0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xa, 0xb,
+			0xc, 0xd
+		},
+	};
+
+	/* Add the above event to the MKBP keyboard FIFO and raise the event */
+
+	ret = mkbp_fifo_add(expected_event.event_type,
+			    &expected_event.data.key_matrix);
+	activate_mkbp_with_events(BIT(expected_event.event_type));
+
+	zassert_equal(EC_SUCCESS, ret, "Got %d when adding to FIFO", ret);
+
+	/* Retrieve this event via host command */
+
+	struct ec_response_get_next_event response;
+	struct host_cmd_handler_args args =
+		BUILD_HOST_COMMAND_RESPONSE(EC_CMD_GET_NEXT_EVENT, 0, response);
+
+	ret = host_command_process(&args);
+	zassert_equal(EC_RES_SUCCESS, ret, "Expected EC_RES_SUCCESS but got %d",
+		      ret);
+
+	/* Compare event data in response */
+	zassert_equal(expected_event.event_type, response.event_type,
+		      "Got event type 0x%02x", response.event_type);
+	zassert_mem_equal(&expected_event.data.key_matrix,
+			  &response.data.key_matrix,
+			  sizeof(expected_event.data.key_matrix),
+			  "Event data payload does not match.");
+}
+
+/* Set up a mock for mkbp_send_event(). This function is called by the MKBP
+ * event sources to signal that a new event is available for servicing. Since we
+ * are unit testing just event handling code, we do not want the various event
+ * source tasks to raise unexpected events during testing and throw us off.
+ * This mock will essentially cause mkbp_send_event() to become a no-op and
+ * block the reset of the EC code from raising events and interfering. The test
+ * code will bypass this by calling mkbp_event.c's internal
+ * `activate_mkbp_with_events()` directly.
+ */
+FAKE_VALUE_FUNC(int, mkbp_send_event, uint8_t);
+
+static void reset_events(void *data)
+{
+	/* Clear any keyboard scan events (type EC_MKBP_EVENT_KEY_MATRIX) */
+	mkbp_clear_fifo();
+
+	/* Clear pending events */
+	mkbp_event_clear_all();
+
+	/* Mock reset */
+	RESET_FAKE(mkbp_send_event);
+	mkbp_send_event_fake.return_val = 1;
+}
+
+ZTEST_SUITE(mkbp_event, drivers_predicate_post_main, NULL, reset_events,
+	    reset_events, NULL);