[PATCH 2/2] hw/riscv: virt: Allow passing custom DTB

[Anup Patel]

Extend virt machine to allow passing custom DTB using "-dtb"
command-line parameter. This will help users pass modified DTB
to virt machine.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
---
 hw/riscv/virt.c | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c
index 41bd2f38ba..d535119e37 100644
--- a/hw/riscv/virt.c
+++ b/hw/riscv/virt.c
@@ -181,6 +181,7 @@ static void create_fdt(RISCVVirtState *s, const struct 
MemmapEntry *memmap,
 {
     void *fdt;
     int i, cpu, socket;
+    const char *dtb_filename;
     MachineState *mc = MACHINE(s);
     uint64_t addr, size;
     uint32_t *clint_cells, *plic_cells;
@@ -194,10 +195,20 @@ static void create_fdt(RISCVVirtState *s, const struct 
MemmapEntry *memmap,
     hwaddr flashsize = virt_memmap[VIRT_FLASH].size / 2;
     hwaddr flashbase = virt_memmap[VIRT_FLASH].base;
 
-    fdt = s->fdt = create_device_tree(&s->fdt_size);
-    if (!fdt) {
-        error_report("create_device_tree() failed");
-        exit(1);
+    dtb_filename = qemu_opt_get(qemu_get_machine_opts(), "dtb");
+    if (dtb_filename) {
+        fdt = s->fdt = load_device_tree(dtb_filename, &s->fdt_size);
+        if (!fdt) {
+            error_report("load_device_tree() failed");
+            exit(1);
+        }
+        goto update_bootargs;
+    } else {
+        fdt = s->fdt = create_device_tree(&s->fdt_size);
+        if (!fdt) {
+            error_report("create_device_tree() failed");
+            exit(1);
+        }
     }
 
     qemu_fdt_setprop_string(fdt, "/", "model", "riscv-virtio,qemu");
@@ -418,9 +429,6 @@ static void create_fdt(RISCVVirtState *s, const struct 
MemmapEntry *memmap,
 
     qemu_fdt_add_subnode(fdt, "/chosen");
     qemu_fdt_setprop_string(fdt, "/chosen", "stdout-path", name);
-    if (cmdline) {
-        qemu_fdt_setprop_string(fdt, "/chosen", "bootargs", cmdline);
-    }
     g_free(name);
 
     name = g_strdup_printf("/soc/rtc@%lx", (long)memmap[VIRT_RTC].base);
@@ -441,6 +449,11 @@ static void create_fdt(RISCVVirtState *s, const struct 
MemmapEntry *memmap,
                                  2, flashbase + flashsize, 2, flashsize);
     qemu_fdt_setprop_cell(s->fdt, name, "bank-width", 4);
     g_free(name);
+
+update_bootargs:
+    if (cmdline) {
+        qemu_fdt_setprop_string(fdt, "/chosen", "bootargs", cmdline);
+    }
 }
 
 static inline DeviceState *gpex_pcie_init(MemoryRegion *sys_mem,
-- 
2.25.1