1 files changed, 60 insertions, 2 deletions

diff --git a/scripts/dtc/dtc.c b/scripts/dtc/dtc.c
index 8c4add69a765..5fa23c406266 100644
--- a/scripts/dtc/dtc.c
+++ b/scripts/dtc/dtc.c
@@ -18,6 +18,8 @@
  *                                                                   USA
  */
 
+#include <sys/stat.h>
+
 #include "dtc.h"
 #include "srcpos.h"
 
@@ -104,11 +106,56 @@ static const char * const usage_opts_help[] = {
         NULL,
 };
 
+static const char *guess_type_by_name(const char *fname, const char *fallback)
+{
+        const char *s;
+
+        s = strrchr(fname, '.');
+        if (s == NULL)
+                return fallback;
+        if (!strcasecmp(s, ".dts"))
+                return "dts";
+        if (!strcasecmp(s, ".dtb"))
+                return "dtb";
+        return fallback;
+}
+
+static const char *guess_input_format(const char *fname, const char *fallback)
+{
+        struct stat statbuf;
+        uint32_t magic;
+        FILE *f;
+
+        if (stat(fname, &statbuf) != 0)
+                return fallback;
+
+        if (S_ISDIR(statbuf.st_mode))
+                return "fs";
+
+        if (!S_ISREG(statbuf.st_mode))
+                return fallback;
+
+        f = fopen(fname, "r");
+        if (f == NULL)
+                return fallback;
+        if (fread(&magic, 4, 1, f) != 1) {
+                fclose(f);
+                return fallback;
+        }
+        fclose(f);
+
+        magic = fdt32_to_cpu(magic);
+        if (magic == FDT_MAGIC)
+                return "dtb";
+
+        return guess_type_by_name(fname, fallback);
+}
+
 int main(int argc, char *argv[])
 {
         struct boot_info *bi;
-        const char *inform = "dts";
-        const char *outform = "dts";
+        const char *inform = NULL;
+        const char *outform = NULL;
         const char *outname = "-";
         const char *depname = NULL;
         bool force = false, sort = false;
@@ -213,6 +260,17 @@ int main(int argc, char *argv[])
                 fprintf(depfile, "%s:", outname);
         }
 
+        if (inform == NULL)
+                inform = guess_input_format(arg, "dts");
+        if (outform == NULL) {
+                outform = guess_type_by_name(outname, NULL);
+                if (outform == NULL) {
+                        if (streq(inform, "dts"))
+                                outform = "dtb";
+                        else
+                                outform = "dts";
+                }
+        }
         if (streq(inform, "dts"))
                 bi = dt_from_source(arg);
         else if (streq(inform, "fs"))