sandbox: Support trace feature

Support tracing on sandbox by adding suitable CONFIG options. To enable it,
compile U-Boot with FTRACE=1.

The timer functions are marked to skip tracing, since these are called from
the tracing code itself, and we want to avoid an infinite loop.

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/sandbox/cpu/cpu.c

@@ -37,7 +37,7 @@ void __udelay(unsigned long usec)
 	os_usleep(usec);
 }
 
-unsigned long timer_get_us(void)
+unsigned long __attribute__((no_instrument_function)) timer_get_us(void)
 {
 	return os_get_nsec() / 1000;
 }

arch/sandbox/cpu/os.c

@@ -152,7 +152,7 @@ void os_usleep(unsigned long usec)
 	usleep(usec);
 }
 
-u64 os_get_nsec(void)
+u64 __attribute__((no_instrument_function)) os_get_nsec(void)
 {
 #if defined(CLOCK_MONOTONIC) && defined(_POSIX_MONOTONIC_CLOCK)
 	struct timespec tp;

include/configs/sandbox.h

@@ -22,6 +22,19 @@
 #ifndef __CONFIG_H
 #define __CONFIG_H
 
+#ifdef FTRACE
+#define CONFIG_TRACE
+#define CONFIG_CMD_TRACE
+#define CONFIG_TRACE_BUFFER_SIZE	(16 << 20)
+#define CONFIG_TRACE_EARLY_SIZE		(8 << 20)
+#define CONFIG_TRACE_EARLY
+#define CONFIG_TRACE_EARLY_ADDR		0x00100000
+
+#endif
+
+#define CONFIG_BOOTSTAGE
+#define CONFIG_BOOTSTAGE_REPORT
+
 /* Number of bits in a C 'long' on this architecture */
 #define CONFIG_SANDBOX_BITS_PER_LONG	64