msm_rtb: Add snapshot of msm_rtb.h

This is a snapshot of msm_rtb.h file taken as of msm-4.19
commit <cf8acfa8c9b53ad> (Merge "msm: camera: core : Validate
the dev name during the node ioctl handler").

Change-Id: Ia2a2147369328ca6da177bd51c20217df3c4f157
Signed-off-by: Raghavendra Rao Ananta <rananta@codeaurora.org>

include/linux/msm_rtb.h

@@ -0,0 +1,81 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2012-2014, 2016, 2018, The Linux Foundation. All rights reserved.
+ */
+
+#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 \
+	do { \
+		asm volatile("b .+4\n" : : : "memory"); \
+	} while (0)
+
+/*
+ * 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