hw/arm/xlnx-versal: prepare for FDT creation

The following commits will move FDT creation logic from the
xlnx-versal-virt machine to the xlnx-versal SoC itself. Prepare this by
passing the FDT handle to the SoC before it is realized.

For now the SoC only creates the two clock nodes. The ones from the
xlnx-versal virt machine are renamed with a `old-' prefix and will be
removed once they are not referenced anymore.

Signed-off-by: Luc Michel <luc.michel@amd.com>
Reviewed-by: Francisco Iglesias <francisco.iglesias@amd.com>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20250926070806.292065-3-luc.michel@amd.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

3 files changed, 42 insertions, 3 deletions

diff --git a/hw/arm/xlnx-versal-virt.c b/hw/arm/xlnx-versal-virt.c
index adadbb7290..d1c65afa2a 100644
--- a/hw/arm/xlnx-versal-virt.c
+++ b/hw/arm/xlnx-versal-virt.c
@@ -2,6 +2,7 @@
  * Xilinx Versal Virtual board.
  *
  * Copyright (c) 2018 Xilinx Inc.
+ * Copyright (c) 2025 Advanced Micro Devices, Inc.
  * Written by Edgar E. Iglesias
  *
  * This program is free software; you can redistribute it and/or modify
@@ -697,10 +698,12 @@ static void versal_virt_init(MachineState *machine)
                              &error_abort);
     object_property_set_link(OBJECT(&s->soc), "canbus1", OBJECT(s->canbus[1]),
                              &error_abort);
-    sysbus_realize(SYS_BUS_DEVICE(&s->soc), &error_fatal);
 
     fdt_create(s);
+    versal_set_fdt(&s->soc, s->fdt);
+    sysbus_realize(SYS_BUS_DEVICE(&s->soc), &error_fatal);
     create_virtio_regions(s);
+
     fdt_add_gem_nodes(s);
     fdt_add_uart_nodes(s);
     fdt_add_canfd_nodes(s);
@@ -714,8 +717,8 @@ static void versal_virt_init(MachineState *machine)
     fdt_add_efuse_ctrl_node(s);
     fdt_add_efuse_cache_node(s);
     fdt_add_cpu_nodes(s, psci_conduit);
-    fdt_add_clk_node(s, "/clk125", 125000000, s->phandle.clk_125Mhz);
-    fdt_add_clk_node(s, "/clk25", 25000000, s->phandle.clk_25Mhz);
+    fdt_add_clk_node(s, "/old-clk125", 125000000, s->phandle.clk_125Mhz);
+    fdt_add_clk_node(s, "/old-clk25", 25000000, s->phandle.clk_25Mhz);
 
     /* Make the APU cpu address space visible to virtio and other
      * modules unaware of multiple address-spaces.  */
diff --git a/hw/arm/xlnx-versal.c b/hw/arm/xlnx-versal.c
index 4da656318f..3b59621956 100644
--- a/hw/arm/xlnx-versal.c
+++ b/hw/arm/xlnx-versal.c
@@ -24,6 +24,8 @@
 #include "qemu/log.h"
 #include "target/arm/cpu-qom.h"
 #include "target/arm/gtimer.h"
+#include "system/device_tree.h"
+#include "hw/arm/fdt.h"
 
 #define XLNX_VERSAL_ACPU_TYPE ARM_CPU_TYPE_NAME("cortex-a72")
 #define XLNX_VERSAL_RCPU_TYPE ARM_CPU_TYPE_NAME("cortex-r5f")
@@ -919,11 +921,33 @@ static void versal_unimp(Versal *s)
                                 gpio_in);
 }
 
+static uint32_t fdt_add_clk_node(Versal *s, const char *name,
+                                 unsigned int freq_hz)
+{
+    uint32_t phandle;
+
+    phandle = qemu_fdt_alloc_phandle(s->cfg.fdt);
+
+    qemu_fdt_add_subnode(s->cfg.fdt, name);
+    qemu_fdt_setprop_cell(s->cfg.fdt, name, "phandle", phandle);
+    qemu_fdt_setprop_cell(s->cfg.fdt, name, "clock-frequency", freq_hz);
+    qemu_fdt_setprop_cell(s->cfg.fdt, name, "#clock-cells", 0x0);
+    qemu_fdt_setprop_string(s->cfg.fdt, name, "compatible", "fixed-clock");
+    qemu_fdt_setprop(s->cfg.fdt, name, "u-boot,dm-pre-reloc", NULL, 0);
+
+    return phandle;
+}
+
 static void versal_realize(DeviceState *dev, Error **errp)
 {
     Versal *s = XLNX_VERSAL_BASE(dev);
     qemu_irq pic[XLNX_VERSAL_NR_IRQS];
 
+    g_assert(s->cfg.fdt != NULL);
+
+    s->phandle.clk_25mhz = fdt_add_clk_node(s, "/clk25", 25 * 1000 * 1000);
+    s->phandle.clk_125mhz = fdt_add_clk_node(s, "/clk125", 125 * 1000 * 1000);
+
     versal_create_apu_cpus(s);
     versal_create_apu_gic(s, pic);
     versal_create_rpu_cpus(s);
diff --git a/include/hw/arm/xlnx-versal.h b/include/hw/arm/xlnx-versal.h
index 1f92e314d6..f2a62b4355 100644
--- a/include/hw/arm/xlnx-versal.h
+++ b/include/hw/arm/xlnx-versal.h
@@ -137,7 +137,13 @@ struct Versal {
     } pmc;
 
     struct {
+        uint32_t clk_25mhz;
+        uint32_t clk_125mhz;
+    } phandle;
+
+    struct {
         MemoryRegion *mr_ddr;
+        void *fdt;
     } cfg;
 };
 
@@ -147,6 +153,12 @@ struct VersalClass {
     VersalVersion version;
 };
 
+static inline void versal_set_fdt(Versal *s, void *fdt)
+{
+    g_assert(!qdev_is_realized(DEVICE(s)));
+    s->cfg.fdt = fdt;
+}
+
 /* Memory-map and IRQ definitions. Copied a subset from
  * auto-generated files.  */