trace: rtb: add msm_rtb register tracing feature snapshot

This snapshot is taken as of msm-3.10 commit:
 78c36fa0ef (Merge "msm: mdss: Prevent backlight update during
 continuous splash")

RTB support captures system events such as register writes to a
small uncached region. This is designed to aid in debugging, where
it may be useful to know the last events that occurred prior to a
device reset.

Change-Id: Idc51e618380f58a6803f40c47f2b3d29033b3196
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>
[spjoshi@codeaurora.org: fix merge conflict]
Signed-off-by: Sarangdhar Joshi <spjoshi@codeaurora.org>

1 files changed, 84 insertions, 0 deletions

diff --git a/include/linux/msm_rtb.h b/include/linux/msm_rtb.h
new file mode 100644
index 000000000000..228094294b31
--- /dev/null
+++ b/include/linux/msm_rtb.h
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2012-2014, The Linux Foundation. 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 version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ */
+#ifndef __MSM_RTB_H__
+#define __MSM_RTB_H__
+
+/*
+ * These numbers are used from the kernel command line and sysfs
+ * to control filtering. Remove items from here with extreme caution.
+ */
+enum logk_event_type {
+	LOGK_NONE = 0,
+	LOGK_READL = 1,
+	LOGK_WRITEL = 2,
+	LOGK_LOGBUF = 3,
+	LOGK_HOTPLUG = 4,
+	LOGK_CTXID = 5,
+	LOGK_TIMESTAMP = 6,
+	LOGK_L2CPREAD = 7,
+	LOGK_L2CPWRITE = 8,
+	LOGK_IRQ = 9,
+};
+
+#define LOGTYPE_NOPC 0x80
+
+struct msm_rtb_platform_data {
+	unsigned int size;
+};
+
+#if defined(CONFIG_QCOM_RTB)
+/*
+ * returns 1 if data was logged, 0 otherwise
+ */
+int uncached_logk_pc(enum logk_event_type log_type, void *caller,
+				void *data);
+
+/*
+ * returns 1 if data was logged, 0 otherwise
+ */
+int uncached_logk(enum logk_event_type log_type, void *data);
+
+#define ETB_WAYPOINT  do { \
+				BRANCH_TO_NEXT_ISTR; \
+				nop(); \
+				BRANCH_TO_NEXT_ISTR; \
+				nop(); \
+			} while (0)
+
+#define BRANCH_TO_NEXT_ISTR  asm volatile("b .+4\n" : : : "memory")
+/*
+ * both the mb and the isb are needed to ensure enough waypoints for
+ * etb tracing
+ */
+#define LOG_BARRIER	do { \
+				mb(); \
+				isb();\
+			 } while (0)
+#else
+
+static inline int uncached_logk_pc(enum logk_event_type log_type,
+					void *caller,
+					void *data) { return 0; }
+
+static inline int uncached_logk(enum logk_event_type log_type,
+					void *data) { return 0; }
+
+#define ETB_WAYPOINT
+#define BRANCH_TO_NEXT_ISTR
+/*
+ * Due to a GCC bug, we need to have a nop here in order to prevent an extra
+ * read from being generated after the write.
+ */
+#define LOG_BARRIER		nop()
+#endif
+#endif