dtc: Implement -d option to write out a dependency file

This will allow callers to rebuild .dtb files when any of the /include/d
.dtsi files are modified, not just the top-level .dts file.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>

3 files changed, 25 insertions, 1 deletions

diff --git a/scripts/dtc/dtc.c b/scripts/dtc/dtc.c
index cbc0193098e4..451c92d31b19 100644
--- a/scripts/dtc/dtc.c
+++ b/scripts/dtc/dtc.c
@@ -71,6 +71,7 @@ static void  __attribute__ ((noreturn)) usage(void)
         fprintf(stderr, "\t\t\tasm - assembler source\n");
         fprintf(stderr, "\t-V <output version>\n");
         fprintf(stderr, "\t\tBlob version to produce, defaults to %d (relevant for dtb\n\t\tand asm output only)\n", DEFAULT_FDT_VERSION);
+        fprintf(stderr, "\t-d <output dependency file>\n");
         fprintf(stderr, "\t-R <number>\n");
         fprintf(stderr, "\t\tMake space for <number> reserve map entries (relevant for \n\t\tdtb and asm output only)\n");
         fprintf(stderr, "\t-S <bytes>\n");
@@ -99,6 +100,7 @@ int main(int argc, char *argv[])
         const char *inform = "dts";
         const char *outform = "dts";
         const char *outname = "-";
+        const char *depname = NULL;
         int force = 0, check = 0, sort = 0;
         const char *arg;
         int opt;
@@ -111,7 +113,8 @@ int main(int argc, char *argv[])
         minsize    = 0;
         padsize    = 0;
 
-        while ((opt = getopt(argc, argv, "hI:O:o:V:R:S:p:fcqb:vH:s")) != EOF) {
+        while ((opt = getopt(argc, argv, "hI:O:o:V:d:R:S:p:fcqb:vH:s"))
+                        != EOF) {
                 switch (opt) {
                 case 'I':
                         inform = optarg;
@@ -125,6 +128,9 @@ int main(int argc, char *argv[])
                 case 'V':
                         outversion = strtol(optarg, NULL, 0);
                         break;
+                case 'd':
+                        depname = optarg;
+                        break;
                 case 'R':
                         reservenum = strtol(optarg, NULL, 0);
                         break;
@@ -188,6 +194,14 @@ int main(int argc, char *argv[])
         fprintf(stderr, "DTC: %s->%s  on file \"%s\"\n",
                 inform, outform, arg);
 
+        if (depname) {
+                depfile = fopen(depname, "w");
+                if (!depfile)
+                        die("Couldn't open dependency file %s: %s\n", depname,
+                            strerror(errno));
+                fprintf(depfile, "%s:", outname);
+        }
+
         if (streq(inform, "dts"))
                 bi = dt_from_source(arg);
         else if (streq(inform, "fs"))
@@ -197,6 +211,11 @@ int main(int argc, char *argv[])
         else
                 die("Unknown input format \"%s\"\n", inform);
 
+        if (depfile) {
+                fputc('\n', depfile);
+                fclose(depfile);
+        }
+
         if (cmdline_boot_cpuid != -1)
                 bi->boot_cpuid_phys = cmdline_boot_cpuid;
 
diff --git a/scripts/dtc/srcpos.c b/scripts/dtc/srcpos.c
index 2dbc874288ca..36a38e9f1a2c 100644
--- a/scripts/dtc/srcpos.c
+++ b/scripts/dtc/srcpos.c
@@ -40,6 +40,7 @@ static char *dirname(const char *path)
         return NULL;
 }
 
+FILE *depfile; /* = NULL */
 struct srcfile_state *current_srcfile; /* = NULL */
 
 /* Detect infinite include recursion. */
@@ -67,6 +68,9 @@ FILE *srcfile_relative_open(const char *fname, char **fullnamep)
                             strerror(errno));
         }
 
+        if (depfile)
+                fprintf(depfile, " %s", fullname);
+
         if (fullnamep)
                 *fullnamep = fullname;
         else
diff --git a/scripts/dtc/srcpos.h b/scripts/dtc/srcpos.h
index bd7966e56a53..ce980cafe588 100644
--- a/scripts/dtc/srcpos.h
+++ b/scripts/dtc/srcpos.h
@@ -30,6 +30,7 @@ struct srcfile_state {
         struct srcfile_state *prev;
 };
 
+extern FILE *depfile; /* = NULL */
 extern struct srcfile_state *current_srcfile; /* = NULL */
 
 FILE *srcfile_relative_open(const char *fname, char **fullnamep);