MKBP event signalling implementation

This implements a new API for EC modules to define MKBP event sources
and send MKBP event to the AP. Also, a new host command
EC_CMD_GET_NEXT_EVENT is added for the AP to query the pending MKBP
events. Each event type may have custom event data sent along with the
event.

BRANCH=None
BUG=chrome-os-partner:33194
TEST=Enable MKBP event on Ryu. Set a host event from EC console, run
'ectool nextevent', and see MKBP event 0x01 (HOST_EVENT) and the set
host event.

Signed-off-by: Vic Yang <victoryang@chromium.org>
Change-Id: I28a1b7e826bcc102bbe39016c9bb3e37d125664c
Reviewed-on: https://chromium-review.googlesource.com/224905
Reviewed-by: Randall Spangler <rspangler@chromium.org>

4 files changed, 68 insertions, 0 deletions

diff --git a/include/config.h b/include/config.h
index e6c0aa8583..7f637423d8 100644
--- a/include/config.h
+++ b/include/config.h
@@ -751,6 +751,9 @@
 /* Support LPC interface */
 #undef CONFIG_LPC
 
+/* Support MKBP event */
+#undef CONFIG_MKBP_EVENT
+
 /* Support memory protection unit (MPU) */
 #undef CONFIG_MPU
 
diff --git a/include/ec_commands.h b/include/ec_commands.h
index 3675dfa6d9..3cea697cf9 100644
--- a/include/ec_commands.h
+++ b/include/ec_commands.h
@@ -1811,6 +1811,29 @@ struct ec_result_keyscan_seq_ctrl {
 	};
 } __packed;
 
+/*
+ * Get the next pending MKBP event.
+ *
+ * Returns EC_RES_UNAVAILABLE if there is no event pending.
+ */
+#define EC_CMD_GET_NEXT_EVENT 0x67
+
+enum ec_mkbp_event {
+	/* Keyboard matrix changed. The event data is the new matrix state. */
+	EC_MKBP_EVENT_KEY_MATRIX = 0,
+
+	/* New host event. The event data is 4 bytes of host event flags. */
+	EC_MKBP_EVENT_HOST_EVENT = 1,
+
+	/* Number of MKBP events */
+	EC_MKBP_EVENT_COUNT,
+};
+
+struct ec_response_get_next_event {
+	uint8_t event_type;
+	/* Followed by event data if any */
+} __packed;
+
 /*****************************************************************************/
 /* Temperature sensor commands */
 
diff --git a/include/link_defs.h b/include/link_defs.h
index 0aab55befe..67ae9779d2 100644
--- a/include/link_defs.h
+++ b/include/link_defs.h
@@ -11,6 +11,7 @@
 #include "console.h"
 #include "hooks.h"
 #include "host_command.h"
+#include "mkbp_event.h"
 #include "task.h"
 #include "test_util.h"
 
@@ -75,6 +76,10 @@ extern const struct test_i2c_read_string_dev __test_i2c_read_string_end[];
 extern const struct host_command __hcmds[];
 extern const struct host_command __hcmds_end[];
 
+/* MKBP events */
+extern const struct mkbp_event_source __mkbp_evt_srcs[];
+extern const struct mkbp_event_source __mkbp_evt_srcs_end[];
+
 /* IRQs (interrupt handlers) */
 extern const struct irq_priority __irqprio[];
 extern const struct irq_priority __irqprio_end[];
diff --git a/include/mkbp_event.h b/include/mkbp_event.h
new file mode 100644
index 0000000000..8da19fc02d
--- /dev/null
+++ b/include/mkbp_event.h
@@ -0,0 +1,37 @@
+/* Copyright 2014 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Event handling in MKBP keyboard protocol
+ */
+
+#ifndef __CROS_EC_MKBP_EVENT_H
+#define __CROS_EC_MKBP_EVENT_H
+
+/*
+ * Sends an event to the AP.
+ *
+ * When this is called, the event data must be ready for query.  Otherwise,
+ * when the AP queries the event, an error is returned and the event is lost.
+ *
+ * @param event_type  One of EC_MKBP_EVENT_*.
+ */
+void mkbp_send_event(uint8_t event_type);
+
+/*
+ * The struct to store the event source definition.  The get_data routine is
+ * responsible for returning the event data when queried by the AP.  The
+ * parameter 'data' points to where the event data needs to be stored, and
+ * the size of the event data should be returned.
+ */
+struct mkbp_event_source {
+	uint8_t event_type;
+	int (*get_data)(uint8_t *data);
+};
+
+#define DECLARE_EVENT_SOURCE(type, func)                   \
+	const struct mkbp_event_source __evt_src_##type \
+	__attribute__((section(".rodata.evtsrcs")))        \
+		 = {type, func}
+
+#endif  /* __CROS_EC_MKBP_EVENT_H */