pd_log: Make PD logging more generic for general purpose logging

We can re-use our pd_log FIFO for other purposes, such as TPM logging.
Carve out event_log, a generic logging module which pd_log is compatible
with.

 Conflicts:
    (deleted boards)
	board/fizz/board.h
	board/nefario/board.h
	board/reef_it8320/board.h
	board/scarlet/board.h
	board/zoombini/board.h

BUG=b:63760920
TEST=On kevin, verify PD logging is still functional and entries are
seen in dmesg.
BRANCH=None

Change-Id: I8e6ad6f93e9eebc676aca64652c60f81da471a94
Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/597314
Commit-Ready: Shawn N <shawnn@chromium.org>
Tested-by: Shawn N <shawnn@chromium.org>
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
(cherry picked from commit ec99f3913791bfe1935735ddcda18bd29ffcfd18)
Reviewed-on: https://chromium-review.googlesource.com/599500
Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>
Tested-by: Vadim Bendebury <vbendeb@chromium.org>
Commit-Queue: Vadim Bendebury <vbendeb@chromium.org>

3 files changed, 42 insertions, 3 deletions

diff --git a/include/config.h b/include/config.h
index 1a05fbd086..f960fa7237 100644
--- a/include/config.h
+++ b/include/config.h
@@ -2438,8 +2438,8 @@
 /* Record main PD events in a circular buffer */
 #undef CONFIG_USB_PD_LOGGING
 
-/* The size in bytes of the FIFO used for PD events logging */
-#undef CONFIG_USB_PD_LOG_SIZE
+/* The size in bytes of the FIFO used for event logging */
+#define CONFIG_EVENT_LOG_SIZE 512
 
 /* Save power by waking up on VBUS rather than polling CC */
 #define CONFIG_USB_PD_LOW_POWER
diff --git a/include/ec_commands.h b/include/ec_commands.h
index bfa68b52fb..b223b98772 100644
--- a/include/ec_commands.h
+++ b/include/ec_commands.h
@@ -3905,7 +3905,11 @@ struct __ec_align2 ec_params_charge_port_override {
 	int16_t override_port; /* Override port# */
 };
 
-/* Read (and delete) one entry of PD event log */
+/*
+ * Read (and delete) one entry of PD event log.
+ * TODO(crbug.com/751742): Make this host command more generic to accommodate
+ * future non-PD logs that use the same internal EC event_log.
+ */
 #define EC_CMD_PD_GET_LOG_ENTRY 0x0115
 
 struct __ec_align4 ec_response_pd_log {
diff --git a/include/event_log.h b/include/event_log.h
new file mode 100644
index 0000000000..45b10a3a2d
--- /dev/null
+++ b/include/event_log.h
@@ -0,0 +1,35 @@
+/* Copyright 2017 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.
+ */
+
+#ifndef __CROS_EC_EVENT_LOG_H
+#define __CROS_EC_EVENT_LOG_H
+
+struct event_log_entry {
+	uint32_t timestamp; /* relative timestamp in milliseconds */
+	uint8_t type;       /* event type, caller-defined */
+	uint8_t size;       /* [7:5] caller-def'd [4:0] payload size in bytes */
+	uint16_t data;      /* type-defined data payload */
+	uint8_t payload[0]; /* optional additional data payload: 0..16 bytes */
+} __packed;
+
+#define EVENT_LOG_SIZE_MASK  0x1f
+#define EVENT_LOG_SIZE(size) ((size) & EVENT_LOG_SIZE_MASK)
+
+/* The timestamp is the microsecond counter shifted to get about a ms. */
+#define EVENT_LOG_TIMESTAMP_SHIFT 10 /* 1 LSB = 1024us */
+/* Returned in the "type" field, when there is no entry available */
+#define EVENT_LOG_NO_ENTRY 0xff
+
+/* Add an entry to the event log. */
+void log_add_event(uint8_t type, uint8_t size, uint16_t data,
+		   void *payload, uint32_t timestamp);
+
+/*
+ * Remove and return an entry from the event log, if available.
+ * Returns size of log entry *r.
+ */
+int log_dequeue_event(struct event_log_entry *r);
+
+#endif /* __CROS_EC_EVENT_LOG_H */