ff-testdev.c

#include "config-host.h"
#include <sys/mman.h>
#include "hw/hw.h"
#include "hw/qdev.h"
#include "hw/isa/isa.h"

typedef struct FFTestdev {
	ISADevice parent_obj;
	MemoryRegion ioport;
	uint32_t ioport_data;
} FFTestdev;

#define TYPE_TESTDEV "ff-testdev"
#define TESTDEV(obj) OBJECT_CHECK(FFTestdev, (obj), TYPE_TESTDEV)

static void test_ioport_write(void *opaque, hwaddr addr, uint64_t data, unsigned len)
{
	FFTestdev *dev = opaque;
	int bits = len * 8;
	int start_bit = (addr & 3) * 8;
	uint32_t mask = ((uint32_t) -1 >> (32 - bits)) << start_bit;
	dev->ioport_data &= ~mask;
	dev->ioport_data |= data << start_bit;
}

static uint64_t test_ioport_read(void *opaque, hwaddr addr, unsigned len)
{
	FFTestdev *dev = opaque;
	int bits = len * 8;
	int start_bit = (addr & 3) * 8;
	uint32_t mask = ((uint32_t) -1 >> (32 - bits)) << start_bit;
	return (dev->ioport_data & mask) >> start_bit;
}

static const MemoryRegionOps test_ioport_ops = {
		.read = test_ioport_read,
		.write = test_ioport_write,
		.endianness = DEVICE_LITTLE_ENDIAN,
};

static void ff_testdev_realizefn(DeviceState *d, Error **errp)
{
	ISADevice *isa = ISA_DEVICE(d);
	FFTestdev *dev = TESTDEV(d);
	MemoryRegion *io = isa_address_space_io(isa);

	memory_region_init_io(&dev->ioport, OBJECT(dev), &test_ioport_ops, dev, "ff-testdev-ioport", 4);
	memory_region_add_subregion(io, 0xe0, &dev->ioport);
}

static void ff_testdev_class_init(ObjectClass *klass, void *data)
{
	DeviceClass *dc = DEVICE_CLASS(klass);

	set_bit(DEVICE_CATEGORY_MISC, dc->categories);
	dc->realize = ff_testdev_realizefn;
}

static const TypeInfo ff_testdev_info = {
		.name = TYPE_TESTDEV,
		.parent = TYPE_ISA_DEVICE,
		.instance_size = sizeof(FFTestdev),
		.class_init = ff_testdev_class_init,
};

static void ff_register_types(void)
{
	type_register_static(&ff_testdev_info);
}

type_init(ff_register_types)