[Qemu-devel] [PATCH 30/31] dt: Add global option to set phandle start offset

[Alexander Graf]

If anyone outside of QEMU wants to mess with a QEMU generated device tree,
he needs to know which range phandles are valid in. So let's expose a
machine option that an external program can use to set the start allocate
id for phandles in QEMU.

Signed-off-by: Alexander Graf <ag...@suse.de>
---
 device_tree.c |   27 ++++++++++++++++++++++++++-
 qemu-config.c |    4 ++++
 2 files changed, 30 insertions(+), 1 deletions(-)

diff --git a/device_tree.c b/device_tree.c
index a2039e5..5bbe3cd 100644
--- a/device_tree.c
+++ b/device_tree.c
@@ -22,6 +22,7 @@
 #include "qemu-common.h"
 #include "device_tree.h"
 #include "hw/loader.h"
+#include "sysemu.h"
 
 #include <libfdt.h>
 
@@ -229,7 +230,31 @@ int qemu_devtree_setprop_phandle(void *fdt, const char 
*node_path,
 
 uint32_t qemu_devtree_alloc_phandle(void *fdt)
 {
-    static int phandle = 0x8000;
+    static int phandle = 0x0;
+
+    /*
+     * We need to find out if the user gave us special instruction at
+     * which phandle id to start allocting phandles.
+     */
+    if (!phandle) {
+        QemuOpts *machine_opts;
+        machine_opts = qemu_opts_find(qemu_find_opts("machine"), 0);
+        if (machine_opts) {
+            const char *phandle_start;
+            phandle_start = qemu_opt_get(machine_opts, "phandle_start");
+            if (phandle_start) {
+                phandle = strtoul(phandle_start, NULL, 0);
+            }
+        }
+    }
+
+    if (!phandle) {
+        /*
+         * None of invalid phandle given on the command line, so fall back to
+         * default starting point.
+         */
+        phandle = 0x8000;
+    }
 
     return phandle++;
 }
diff --git a/qemu-config.c b/qemu-config.c
index ef4714e..a96b247 100644
--- a/qemu-config.c
+++ b/qemu-config.c
@@ -586,6 +586,10 @@ static QemuOptsList qemu_machine_opts = {
             .name = "dumpdtb",
             .type = QEMU_OPT_STRING,
             .help = "Dump current dtb to a file and quit",
+        }, {
+            .name = "phandle_start",
+            .type = QEMU_OPT_STRING,
+            .help = "The first phandle ID we may generate dynamically",
         },
         { /* End of list */ }
     },
-- 
1.6.0.2