[Qemu-devel] [PATCH 2/8] PPC: e500: allow users to set the /compatible property via -machine

[Alexander Graf <agraf@suse.de>]

Device trees usually have a node /compatible, which indicate which machine
type we're looking at. For quick prototyping, it can be very useful to change
the contents of that node via the command line.

Thus, introduce a new option to -machine called dt_compatible, which when
set changes the /compatible contents to its value.

Signed-off-by: Alexander Graf <agraf@suse.de>
---
 hw/ppce500_mpc8544ds.c |   12 +++++++++---
 qemu-config.c          |    4 ++++
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/hw/ppce500_mpc8544ds.c b/hw/ppce500_mpc8544ds.c
index f6da25b..d38ad99 100644
--- a/hw/ppce500_mpc8544ds.c
+++ b/hw/ppce500_mpc8544ds.c
@@ -119,7 +119,8 @@ static int mpc8544_load_device_tree(CPUPPCState *env,
     uint32_t clock_freq = 400000000;
     uint32_t tb_freq = 400000000;
     int i;
-    char compatible[] = "MPC8544DS\0MPC85xxDS";
+    const char *compatible = "MPC8544DS\0MPC85xxDS";
+    int compatible_len = sizeof("MPC8544DS\0MPC85xxDS");
     char compatible_sb[] = "fsl,mpc8544-immr\0simple-bus";
     char model[] = "MPC8544DS";
     char soc[128];
@@ -144,8 +145,14 @@ static int mpc8544_load_device_tree(CPUPPCState *env,
 
     machine_opts = qemu_opts_find(qemu_find_opts("machine"), 0);
     if (machine_opts) {
+        const char *tmp;
         dumpdtb = qemu_opt_get(machine_opts, "dumpdtb");
         dtb_file = qemu_opt_get(machine_opts, "dtb");
+        tmp = qemu_opt_get(machine_opts, "dt_compatible");
+        if (tmp) {
+            compatible = tmp;
+            compatible_len = strlen(compatible) + 1;
+        }
     }
 
     if (dtb_file) {
@@ -169,8 +176,7 @@ static int mpc8544_load_device_tree(CPUPPCState *env,
 
     /* Manipulate device tree in memory. */
     qemu_devtree_setprop_string(fdt, "/", "model", model);
-    qemu_devtree_setprop(fdt, "/", "compatible", compatible,
-                         sizeof(compatible));
+    qemu_devtree_setprop(fdt, "/", "compatible", compatible, compatible_len);
     qemu_devtree_setprop_cell(fdt, "/", "#address-cells", 2);
     qemu_devtree_setprop_cell(fdt, "/", "#size-cells", 2);
 
diff --git a/qemu-config.c b/qemu-config.c
index 2cd2726..5c3296b 100644
--- a/qemu-config.c
+++ b/qemu-config.c
@@ -591,6 +591,10 @@ static QemuOptsList qemu_machine_opts = {
             .name = "phandle_start",
             .type = QEMU_OPT_STRING,
             .help = "The first phandle ID we may generate dynamically",
+        }, {
+            .name = "dt_compatible",
+            .type = QEMU_OPT_STRING,
+            .help = "Overrides the \"compatible\" property of the dt root node",
         },
         { /* End of list */ }
     },
-- 
1.6.0.2