Add and register function to create an device tree entry when
the device is added to the qemu platform bus.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-ID: <20250225163031.1409078-20-kraxel@redhat.com>
---
 hw/core/sysbus-fdt.c         | 24 ++++++++++++++++++++++++
 hw/uefi/var-service-sysbus.c |  1 +
 2 files changed, 25 insertions(+)

diff --git a/hw/core/sysbus-fdt.c b/hw/core/sysbus-fdt.c
index 774c0aed41b5..e85066b90563 100644
--- a/hw/core/sysbus-fdt.c
+++ b/hw/core/sysbus-fdt.c
@@ -36,6 +36,7 @@
 #include "hw/vfio/vfio-calxeda-xgmac.h"
 #include "hw/vfio/vfio-amd-xgbe.h"
 #include "hw/display/ramfb.h"
+#include "hw/uefi/var-service-api.h"
 #include "hw/arm/fdt.h"
 
 /*
@@ -471,6 +472,28 @@ static int add_tpm_tis_fdt_node(SysBusDevice *sbdev, void *opaque)
 }
 #endif
 
+static int add_uefi_vars_node(SysBusDevice *sbdev, void *opaque)
+{
+    PlatformBusFDTData *data = opaque;
+    PlatformBusDevice *pbus = data->pbus;
+    const char *parent_node = data->pbus_node_name;
+    void *fdt = data->fdt;
+    uint64_t mmio_base;
+    char *nodename;
+
+    mmio_base = platform_bus_get_mmio_addr(pbus, sbdev, 0);
+    nodename = g_strdup_printf("%s/%s@%" PRIx64, parent_node,
+                               UEFI_VARS_FDT_NODE, mmio_base);
+    qemu_fdt_add_subnode(fdt, nodename);
+    qemu_fdt_setprop_string(fdt, nodename,
+                            "compatible", UEFI_VARS_FDT_COMPAT);
+    qemu_fdt_setprop_sized_cells(fdt, nodename, "reg",
+                                 1, mmio_base,
+                                 1, UEFI_VARS_REGS_SIZE);
+    g_free(nodename);
+    return 0;
+}
+
 static int no_fdt_node(SysBusDevice *sbdev, void *opaque)
 {
     return 0;
@@ -495,6 +518,7 @@ static const BindingEntry bindings[] = {
     TYPE_BINDING(TYPE_TPM_TIS_SYSBUS, add_tpm_tis_fdt_node),
 #endif
     TYPE_BINDING(TYPE_RAMFB_DEVICE, no_fdt_node),
+    TYPE_BINDING(TYPE_UEFI_VARS_SYSBUS, add_uefi_vars_node),
     TYPE_BINDING("", NULL), /* last element */
 };
 
diff --git a/hw/uefi/var-service-sysbus.c b/hw/uefi/var-service-sysbus.c
index 60072c8815cd..28572981c2af 100644
--- a/hw/uefi/var-service-sysbus.c
+++ b/hw/uefi/var-service-sysbus.c
@@ -69,6 +69,7 @@ static void uefi_vars_sysbus_class_init(ObjectClass *klass, void *data)
 
     dc->realize = uefi_vars_sysbus_realize;
     dc->vmsd = &vmstate_uefi_vars_sysbus;
+    dc->user_creatable = true;
     device_class_set_legacy_reset(dc, uefi_vars_sysbus_reset);
     device_class_set_props(dc, uefi_vars_sysbus_properties);
     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
-- 
2.48.1