sandbox: Allow the console to work earlier

With sandbox, errors and problems may be reported before console_init_f()
is executed. For example, an argument may not parse correctly or U-Boot may
panic(). At present this output is swallowed so there is no indication what
is going wrong.

Adjust the console to deal with a very early sandbox setup, by detecting that
there is no global_data yet, and calling os functions in that case.

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

arch/sandbox/cpu/os.c

@@ -388,3 +388,14 @@ ssize_t os_get_filesize(const char *fname)
 		return ret;
 	return buf.st_size;
 }
+
+void os_putc(int ch)
+{
+	putchar(ch);
+}
+
+void os_puts(const char *str)
+{
+	while (*str)
+		os_putc(*str++);
+}

common/console.c

@@ -8,6 +8,7 @@
 #include <common.h>
 #include <stdarg.h>
 #include <malloc.h>
+#include <os.h>
 #include <serial.h>
 #include <stdio_dev.h>
 #include <exports.h>
@@ -415,6 +416,12 @@ static inline void print_pre_console_buffer(void) {}
 
 void putc(const char c)
 {
+#ifdef CONFIG_SANDBOX
+	if (!gd) {
+		os_putc(c);
+		return;
+	}
+#endif
 #ifdef CONFIG_SILENT_CONSOLE
 	if (gd->flags & GD_FLG_SILENT)
 		return;
@@ -439,6 +446,13 @@ void putc(const char c)
 
 void puts(const char *s)
 {
+#ifdef CONFIG_SANDBOX
+	if (!gd) {
+		os_puts(s);
+		return;
+	}
+#endif
+
 #ifdef CONFIG_SILENT_CONSOLE
 	if (gd->flags & GD_FLG_SILENT)
 		return;
@@ -467,7 +481,7 @@ int printf(const char *fmt, ...)
 	uint i;
 	char printbuffer[CONFIG_SYS_PBSIZE];
 
-#ifndef CONFIG_PRE_CONSOLE_BUFFER
+#if !defined(CONFIG_SANDBOX) && !defined(CONFIG_PRE_CONSOLE_BUFFER)
 	if (!gd->have_console)
 		return 0;
 #endif

include/os.h

@@ -209,4 +209,24 @@ const char *os_dirent_get_typename(enum os_dirent_t type);
  */
 ssize_t os_get_filesize(const char *fname);
 
+/**
+ * Write a character to the controlling OS terminal
+ *
+ * This bypasses the U-Boot console support and writes directly to the OS
+ * stdout file descriptor.
+ *
+ * @param ch	Character to write
+ */
+void os_putc(int ch);
+
+/**
+ * Write a string to the controlling OS terminal
+ *
+ * This bypasses the U-Boot console support and writes directly to the OS
+ * stdout file descriptor.
+ *
+ * @param str	String to write (note that \n is not appended)
+ */
+void os_puts(const char *str);
+
 #endif