[RFC PATCH 3/3] board: qemu: m68k: Create virtio mmio instances

Daniel Palmer daniel at thingy.jp
Tue Mar 10 14:59:40 CET 2026


So that you can use virtio network, block etc create the virtio mmio
instances. There are 128 of these even if they are not all used, a
single mmio base value is passed via bootinfo.

Signed-off-by: Daniel Palmer <daniel at thingy.jp>
---
 arch/m68k/Kconfig                     | 14 ++++----
 board/emulation/qemu-m68k/qemu-m68k.c | 46 +++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 6 deletions(-)

diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index 6ce8f577e3a1..20a112880c87 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -195,12 +195,14 @@ config TARGET_STMARK2
         select M54418
 
 config TARGET_QEMU_M68K
-    bool "Support QEMU m68k virt"
-    select M68040
-    imply CMD_DM
-    help
-      This target supports the QEMU m68k virtual machine (-M virt).
-      It simulates a Motorola 68040 CPU with Goldfish peripherals.
+	bool "Support QEMU m68k virt"
+	select M68040
+	select BOARD_EARLY_INIT_R
+	select VIRTIO_MMIO
+	imply CMD_DM
+	help
+	  This target supports the QEMU m68k virtual machine (-M virt).
+	  It simulates a Motorola 68040 CPU with Goldfish peripherals.
 
 endchoice
 
diff --git a/board/emulation/qemu-m68k/qemu-m68k.c b/board/emulation/qemu-m68k/qemu-m68k.c
index d3527aee1128..2517ecf1bb8c 100644
--- a/board/emulation/qemu-m68k/qemu-m68k.c
+++ b/board/emulation/qemu-m68k/qemu-m68k.c
@@ -14,9 +14,14 @@
 #include <asm/bootinfo.h>
 #include <asm/global_data.h>
 #include <asm/io.h>
+#include <dm.h>
+#include <dm/device-internal.h>
+#include <dm/lists.h>
 #include <dm/platdata.h>
+#include <dm/root.h>
 #include <linux/errno.h>
 #include <linux/sizes.h>
+#include <virtio_mmio.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -25,6 +30,37 @@ static struct goldfish_rtc_plat rtc_plat;
 static struct goldfish_timer_plat timer_plat;
 static struct qemu_virt_ctrl_plat reset_plat;
 
+#define VIRTIO_MMIO_NUM	128
+#define VIRTIO_MMIO_SZ	0x200
+
+static struct virtio_mmio_plat virtio_mmio_plat[VIRTIO_MMIO_NUM] = { 0 };
+static char virtio_mmio_names[VIRTIO_MMIO_NUM][11] = { 0 };
+static phys_addr_t virtio_mmio_base = 0;
+
+static inline int create_virtio_mmios(void)
+{
+	struct driver *drv;
+	int i, ret;
+
+	if (!virtio_mmio_base)
+		return -ENODEV;
+
+	drv = lists_driver_lookup_name("virtio-mmio");
+	if (!drv)
+		return -ENOENT;
+
+	for (i = 0; i < VIRTIO_MMIO_NUM; i++) {
+		virtio_mmio_plat[i].base = virtio_mmio_base + (VIRTIO_MMIO_SZ * i);
+		sprintf(virtio_mmio_names[i], "virtio-%d", i);
+
+		ret = device_bind(dm_root(), drv, virtio_mmio_names[i], &virtio_mmio_plat[i], ofnode_null(), NULL);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
 /*
  * Theoretical limit derivation:
  * Max Bootinfo Size (Standard Page) = 4096 bytes
@@ -65,6 +101,9 @@ static void parse_bootinfo(void)
 		case BI_VIRT_CTRL_BASE:
 			reset_plat.reg = base;
 			break;
+		case BI_VIRT_VIRTIO_BASE:
+			virtio_mmio_base = base;
+			break;
 		case BI_MEMCHUNK:
 			gd->ram_size = record->data[1];
 			break;
@@ -80,6 +119,13 @@ int board_early_init_f(void)
 	return 0;
 }
 
+int board_early_init_r(void)
+{
+	create_virtio_mmios();
+
+	return 0;
+}
+
 int checkboard(void)
 {
 	puts("Board: QEMU m68k virt\n");
-- 
2.51.0



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