m68k: Introduce a virtual m68k machine

This machine allows to have up to 3.2 GiB and 128 Virtio devices.

It is based on android goldfish devices.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Link: https://lore.kernel.org/r/20220406201523.243733-5-laurent@vivier.eu
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

1 files changed, 72 insertions, 0 deletions

diff --git a/arch/m68k/virt/platform.c b/arch/m68k/virt/platform.c
new file mode 100644
index 000000000000..cb820f19a221
--- /dev/null
+++ b/arch/m68k/virt/platform.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/memblock.h>
+#include <asm/virt.h>
+#include <asm/irq.h>
+
+#define VIRTIO_BUS_NB	128
+
+static int __init virt_virtio_init(unsigned int id)
+{
+	const struct resource res[] = {
+		DEFINE_RES_MEM(virt_bi_data.virtio.mmio + id * 0x200, 0x200),
+		DEFINE_RES_IRQ(virt_bi_data.virtio.irq + id),
+	};
+	struct platform_device *pdev;
+
+	pdev = platform_device_register_simple("virtio-mmio", id,
+					       res, ARRAY_SIZE(res));
+	if (IS_ERR(pdev))
+		return PTR_ERR(pdev);
+
+	return 0;
+}
+
+static int __init virt_platform_init(void)
+{
+	const struct resource goldfish_tty_res[] = {
+		DEFINE_RES_MEM(virt_bi_data.tty.mmio, 1),
+		DEFINE_RES_IRQ(virt_bi_data.tty.irq),
+	};
+	/* this is the second gf-rtc, the first one is used by the scheduler */
+	const struct resource goldfish_rtc_res[] = {
+		DEFINE_RES_MEM(virt_bi_data.rtc.mmio + 0x1000, 0x1000),
+		DEFINE_RES_IRQ(virt_bi_data.rtc.irq + 1),
+	};
+	struct platform_device *pdev;
+	unsigned int i;
+
+	if (!MACH_IS_VIRT)
+		return -ENODEV;
+
+	/* We need this to have DMA'able memory provided to goldfish-tty */
+	min_low_pfn = 0;
+
+	pdev = platform_device_register_simple("goldfish_tty",
+					       PLATFORM_DEVID_NONE,
+					       goldfish_tty_res,
+					       ARRAY_SIZE(goldfish_tty_res));
+	if (IS_ERR(pdev))
+		return PTR_ERR(pdev);
+
+	pdev = platform_device_register_simple("goldfish_rtc",
+					       PLATFORM_DEVID_NONE,
+					       goldfish_rtc_res,
+					       ARRAY_SIZE(goldfish_rtc_res));
+	if (IS_ERR(pdev))
+		return PTR_ERR(pdev);
+
+	for (i = 0; i < VIRTIO_BUS_NB; i++) {
+		int err;
+
+		err = virt_virtio_init(i);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+arch_initcall(virt_platform_init);