ELOG: Add support for flash based event log

This is based around the SMBIOS event log specification but
expanded with OEM event types to support more specific and
relevant system events.

It requires flash storage and a minimum 4K block (or flash block
size) that should be allocated in the FMAP.

A copy of the event log is maintained in memory for convenience
and speed and the in-memory copy is written to flash at specific
points.

The log is automatically shunk when it reaches a configurable
full threshold in order to not get stuck with a full log that
needs OS help to clear.

ELOG implements the specification published here:
http://code.google.com/p/firmware-event-log/wiki/FirmwareEventLogDesign

And is similar to what we use in other firmware at Google.
This implementation does not support double-buffered flash
regions.  This is done because speed is valued over the log
reliability and it keeps the code simpler for the first version.

This is a large commit and by itself it just provides a new
driver that is made available to coreboot.  Without additional
patches it is not very useful, but the end result is an event
log that will contain entries like this:

171 | 2012-06-23 16:02:55 | System boot | 285
172 | 2012-06-23 16:02:55 | EC Event | Power Button
173 | 2012-06-23 16:02:55 | SUS Power Fail
174 | 2012-06-23 16:02:55 | System Reset
175 | 2012-06-23 16:02:55 | ACPI Wake | S5

Change-Id: I985524c67f525c8a268eccbd856c1a4c2a426889
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: http://review.coreboot.org/1311
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

1 files changed, 76 insertions, 0 deletions

diff --git a/src/drivers/elog/elog_internal.h b/src/drivers/elog/elog_internal.h
new file mode 100644
index 0000000000..2a6a0b7fc4
--- /dev/null
+++ b/src/drivers/elog/elog_internal.h
@@ -0,0 +1,76 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2012 The ChromiumOS Authors.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA, 02110-1301 USA
+ */
+
+#ifndef ELOG_INTERNAL_H_
+#define ELOG_INTERNAL_H_
+
+/* ELOG header */
+struct elog_header {
+	u32 magic;
+	u8 version;
+	u8 header_size;
+	u8 reserved[2];
+} __attribute__ ((packed));
+
+/* ELOG related constants */
+#define ELOG_SIGNATURE			0x474f4c45  /* 'ELOG' */
+#define ELOG_VERSION			1
+
+typedef enum elog_descriptor_type {
+	ELOG_DESCRIPTOR_UNKNOWN,
+	ELOG_DESCRIPTOR_MEMORY,
+	ELOG_DESCRIPTOR_FLASH,
+} elog_descriptor_type;
+
+typedef enum elog_area_state {
+	ELOG_AREA_UNDEFINED,		/* Initial boot strap state */
+	ELOG_AREA_EMPTY,		/* Entire area is empty */
+	ELOG_AREA_HAS_CONTENT,		/* Area has some content */
+} elog_area_state;
+
+typedef enum elog_header_state {
+	ELOG_HEADER_INVALID,
+	ELOG_HEADER_VALID,
+} elog_header_state;
+
+typedef enum elog_event_buffer_state {
+	ELOG_EVENT_BUFFER_OK,
+	ELOG_EVENT_BUFFER_CORRUPTED,
+} elog_event_buffer_state;
+
+/*
+ * Internal handler for event log buffers
+ */
+struct elog_descriptor {
+	elog_descriptor_type	type;
+	elog_area_state		area_state;
+	elog_header_state	header_state;
+	elog_event_buffer_state	event_buffer_state;
+	struct elog_header	*staging_header;
+	void                    *backing_store;
+	u8			*data;
+	u16                     total_size;
+	u16			data_size;
+	u16			next_event_offset;
+	u16			last_event_offset;
+	u16			last_event_size;
+	u16			event_count;
+};
+
+#endif /* ELOG_INTERNAL_H_ */