[PATCH] commands: go: support passing integer arguments instead of argc/argv

The go command accepts extra arguments, which are passed through to the
application using two parameters: argc to hold the number of arguments
and argv as a NULL pointer terminated array of pointers to
nul-terminated strings.

As the go command is meant to invoke bare metal applications, it is
useful to be able to pass arguments parsed to integers using the
default calling convention, so add a new -i argument. The old behavior
remains the default and a new -s arguments makes it explicit for
symmetry.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 commands/Kconfig |  5 ++++-
 commands/go.c    | 54 +++++++++++++++++++++++++++++++++++++++++-------
 2 files changed, 51 insertions(+), 8 deletions(-)

diff --git a/commands/Kconfig b/commands/Kconfig
index 7ca7b56fa54e..987cc286fc73 100644
--- a/commands/Kconfig
+++ b/commands/Kconfig

@@ -461,12 +461,15 @@ config CMD_GO
 	help
 	  Start application at address or file
 
-	  Usage: go ADDR [ARG...]
+	  Usage: go [-si] ADDR [ARG...]
 
 	  Start application at ADDR passing ARG as arguments.
 
 	  If addr does not start with a digit it is interpreted as a filename
 	  in which case the file is memmapped and executed
+	  Options:
+		  -s	pass all arguments as strings referenced by argc, argv arguments (default)
+		  -i	pass up to four integer arguments using default calling convention
 
 config CMD_LOADB
 	depends on CONSOLE_FULL

diff --git a/commands/go.c b/commands/go.c
index 0c0b4cb15e4d..c0c0f5a0c562 100644
--- a/commands/go.c
+++ b/commands/go.c

@@ -8,21 +8,44 @@
 #include <complete.h>
 #include <fs.h>
 #include <fcntl.h>
+#include <getopt.h>
 #include <linux/ctype.h>
 #include <errno.h>
 
+#define INT_ARGS_MAX	4
+
 static int do_go(int argc, char *argv[])
 {
 	void	*addr;
 	int     rcode = 1;
 	int	fd = -1;
-	int	(*func)(int argc, char *argv[]);
+	void	(*func)(ulong r0, ulong r1, ulong r2, ulong r3);
+	int	opt;
+	ulong	arg[INT_ARGS_MAX] = {};
+	bool	pass_argv = true;
 
-	if (argc < 2)
+	while ((opt = getopt(argc, argv, "+si")) > 0) {
+		switch (opt) {
+		case 's':
+			pass_argv = true;
+			break;
+		case 'i':
+			pass_argv = false;
+			break;
+		default:
+			return COMMAND_ERROR_USAGE;
+		}
+	}
+
+	/* skip options */
+	argv += optind;
+	argc -= optind;
+
+	if (argc == 0 || (!pass_argv && argc - 1 > INT_ARGS_MAX))
 		return COMMAND_ERROR_USAGE;
 
-	if (!isdigit(*argv[1])) {
-		fd = open(argv[1], O_RDONLY);
+	if (!isdigit(*argv[0])) {
+		fd = open(argv[0], O_RDONLY);
 		if (fd < 0) {
 			perror("open");
 			goto out;

@@ -34,7 +57,7 @@ static int do_go(int argc, char *argv[])
 			goto out;
 		}
 	} else
-		addr = (void *)simple_strtoul(argv[1], NULL, 16);
+		addr = (void *)simple_strtoul(argv[0], NULL, 16);
 
 	printf("## Starting application at 0x%p ...\n", addr);
 

@@ -44,7 +67,21 @@ static int do_go(int argc, char *argv[])
 
 	shutdown_barebox();
 
-	func(argc - 1, &argv[1]);
+	if (pass_argv) {
+		arg[0] = argc;
+		arg[1] = (ulong)argv;
+	} else {
+		int i;
+
+		/* skip argv[0] */
+		argc--;
+		argv++;
+
+		for (i = 0; i < argc; i++)
+			kstrtoul(argv[i], 0, &arg[i]);