[linux.git] / samples / vfio-mdev / mdpy.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Mediated virtual PCI display host device driver
 *
 * See mdpy-defs.h for device specs
 *
 *   (c) Gerd Hoffmann <[email protected]>
 *
 * based on mtty driver which is:
 *   Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
 *	 Author: Neo Jia <[email protected]>
 *		 Kirti Wankhede <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/cdev.h>
#include <linux/vfio.h>
#include <linux/iommu.h>
#include <linux/sysfs.h>
#include <linux/mdev.h>
#include <linux/pci.h>
#include <drm/drm_fourcc.h>
#include "mdpy-defs.h"

#define MDPY_NAME		"mdpy"
#define MDPY_CLASS_NAME		"mdpy"

#define MDPY_CONFIG_SPACE_SIZE	0xff
#define MDPY_MEMORY_BAR_OFFSET	PAGE_SIZE
#define MDPY_DISPLAY_REGION	16

#define STORE_LE16(addr, val)	(*(u16 *)addr = val)
#define STORE_LE32(addr, val)	(*(u32 *)addr = val)


MODULE_LICENSE("GPL v2");

static int max_devices = 4;
module_param_named(count, max_devices, int, 0444);
MODULE_PARM_DESC(count, "number of " MDPY_NAME " devices");


#define MDPY_TYPE_1 "vga"
#define MDPY_TYPE_2 "xga"
#define MDPY_TYPE_3 "hd"

static const struct mdpy_type {
	const char *name;
	u32 format;
	u32 bytepp;
	u32 width;
	u32 height;
} mdpy_types[] = {
	{
		.name	= MDPY_CLASS_NAME "-" MDPY_TYPE_1,
		.format = DRM_FORMAT_XRGB8888,
		.bytepp = 4,
		.width	= 640,
		.height = 480,
	}, {
		.name	= MDPY_CLASS_NAME "-" MDPY_TYPE_2,
		.format = DRM_FORMAT_XRGB8888,
		.bytepp = 4,
		.width	= 1024,
		.height = 768,
	}, {
		.name	= MDPY_CLASS_NAME "-" MDPY_TYPE_3,
		.format = DRM_FORMAT_XRGB8888,
		.bytepp = 4,
		.width	= 1920,
		.height = 1080,
	},
};

static dev_t		mdpy_devt;
static struct class	*mdpy_class;
static struct cdev	mdpy_cdev;
static struct device	mdpy_dev;
static u32		mdpy_count;

/* State of each mdev device */
struct mdev_state {
	u8 *vconfig;
	u32 bar_mask;
	struct mutex ops_lock;
	struct mdev_device *mdev;
	struct vfio_device_info dev_info;

	const struct mdpy_type *type;
	u32 memsize;
	void *memblk;
};

static const struct mdpy_type *mdpy_find_type(struct kobject *kobj)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(mdpy_types); i++)
		if (strcmp(mdpy_types[i].name, kobj->name) == 0)
			return mdpy_types + i;
	return NULL;
}

static void mdpy_create_config_space(struct mdev_state *mdev_state)
{
	STORE_LE16((u16 *) &mdev_state->vconfig[PCI_VENDOR_ID],
		   MDPY_PCI_VENDOR_ID);
	STORE_LE16((u16 *) &mdev_state->vconfig[PCI_DEVICE_ID],
		   MDPY_PCI_DEVICE_ID);
	STORE_LE16((u16 *) &mdev_state->vconfig[PCI_SUBSYSTEM_VENDOR_ID],
		   MDPY_PCI_SUBVENDOR_ID);
	STORE_LE16((u16 *) &mdev_state->vconfig[PCI_SUBSYSTEM_ID],
		   MDPY_PCI_SUBDEVICE_ID);

	STORE_LE16((u16 *) &mdev_state->vconfig[PCI_COMMAND],
		   PCI_COMMAND_IO | PCI_COMMAND_MEMORY);
	STORE_LE16((u16 *) &mdev_state->vconfig[PCI_STATUS],
		   PCI_STATUS_CAP_LIST);
	STORE_LE16((u16 *) &mdev_state->vconfig[PCI_CLASS_DEVICE],
		   PCI_CLASS_DISPLAY_OTHER);
	mdev_state->vconfig[PCI_CLASS_REVISION] =  0x01;

	STORE_LE32((u32 *) &mdev_state->vconfig[PCI_BASE_ADDRESS_0],
		   PCI_BASE_ADDRESS_SPACE_MEMORY |
		   PCI_BASE_ADDRESS_MEM_TYPE_32	 |
		   PCI_BASE_ADDRESS_MEM_PREFETCH);
	mdev_state->bar_mask = ~(mdev_state->memsize) + 1;

	/* vendor specific capability for the config registers */
	mdev_state->vconfig[PCI_CAPABILITY_LIST]       = MDPY_VENDORCAP_OFFSET;
	mdev_state->vconfig[MDPY_VENDORCAP_OFFSET + 0] = 0x09; /* vendor cap */
	mdev_state->vconfig[MDPY_VENDORCAP_OFFSET + 1] = 0x00; /* next ptr */
	mdev_state->vconfig[MDPY_VENDORCAP_OFFSET + 2] = MDPY_VENDORCAP_SIZE;
	STORE_LE32((u32 *) &mdev_state->vconfig[MDPY_FORMAT_OFFSET],
		   mdev_state->type->format);
	STORE_LE32((u32 *) &mdev_state->vconfig[MDPY_WIDTH_OFFSET],
		   mdev_state->type->width);
	STORE_LE32((u32 *) &mdev_state->vconfig[MDPY_HEIGHT_OFFSET],
		   mdev_state->type->height);
}

static void handle_pci_cfg_write(struct mdev_state *mdev_state, u16 offset,
				 char *buf, u32 count)
{
	struct device *dev = mdev_dev(mdev_state->mdev);
	u32 cfg_addr;

	switch (offset) {
	case PCI_BASE_ADDRESS_0:
		cfg_addr = *(u32 *)buf;

		if (cfg_addr == 0xffffffff) {
			cfg_addr = (cfg_addr & mdev_state->bar_mask);
		} else {
			cfg_addr &= PCI_BASE_ADDRESS_MEM_MASK;
			if (cfg_addr)
				dev_info(dev, "BAR0 @ 0x%x\n", cfg_addr);
		}

		cfg_addr |= (mdev_state->vconfig[offset] &
			     ~PCI_BASE_ADDRESS_MEM_MASK);
		STORE_LE32(&mdev_state->vconfig[offset], cfg_addr);
		break;
	}
}

static ssize_t mdev_access(struct mdev_device *mdev, char *buf, size_t count,
			   loff_t pos, bool is_write)
{
	struct mdev_state *mdev_state = mdev_get_drvdata(mdev);
	struct device *dev = mdev_dev(mdev);
	int ret = 0;

	mutex_lock(&mdev_state->ops_lock);

	if (pos < MDPY_CONFIG_SPACE_SIZE) {
		if (is_write)
			handle_pci_cfg_write(mdev_state, pos, buf, count);
		else
			memcpy(buf, (mdev_state->vconfig + pos), count);

	} else if ((pos >= MDPY_MEMORY_BAR_OFFSET) &&
		   (pos + count <=
		    MDPY_MEMORY_BAR_OFFSET + mdev_state->memsize)) {
		pos -= MDPY_MEMORY_BAR_OFFSET;
		if (is_write)
			memcpy(mdev_state->memblk, buf, count);
		else
			memcpy(buf, mdev_state->memblk, count);

	} else {
		dev_info(dev, "%s: %s @0x%llx (unhandled)\n",
			 __func__, is_write ? "WR" : "RD", pos);
		ret = -1;
		goto accessfailed;
	}

	ret = count;


accessfailed:
	mutex_unlock(&mdev_state->ops_lock);

	return ret;
}

static int mdpy_reset(struct mdev_device *mdev)
{
	struct mdev_state *mdev_state = mdev_get_drvdata(mdev);
	u32 stride, i;

	/* initialize with gray gradient */
	stride = mdev_state->type->width * mdev_state->type->bytepp;
	for (i = 0; i < mdev_state->type->height; i++)
		memset(mdev_state->memblk + i * stride,
		       i * 255 / mdev_state->type->height,
		       stride);
	return 0;
}

static int mdpy_create(struct kobject *kobj, struct mdev_device *mdev)
{
	const struct mdpy_type *type = mdpy_find_type(kobj);
	struct device *dev = mdev_dev(mdev);
	struct mdev_state *mdev_state;
	u32 fbsize;

	if (mdpy_count >= max_devices)
		return -ENOMEM;

	mdev_state = kzalloc(sizeof(struct mdev_state), GFP_KERNEL);
	if (mdev_state == NULL)
		return -ENOMEM;

	mdev_state->vconfig = kzalloc(MDPY_CONFIG_SPACE_SIZE, GFP_KERNEL);
	if (mdev_state->vconfig == NULL) {
		kfree(mdev_state);
		return -ENOMEM;
	}

	if (!type)
		type = &mdpy_types[0];
	fbsize = roundup_pow_of_two(type->width * type->height * type->bytepp);

	mdev_state->memblk = vmalloc_user(fbsize);
	if (!mdev_state->memblk) {
		kfree(mdev_state->vconfig);
		kfree(mdev_state);
		return -ENOMEM;
	}
	dev_info(dev, "%s: %s (%dx%d)\n",
		 __func__, kobj->name, type->width, type->height);

	mutex_init(&mdev_state->ops_lock);
	mdev_state->mdev = mdev;
	mdev_set_drvdata(mdev, mdev_state);

	mdev_state->type    = type;
	mdev_state->memsize = fbsize;
	mdpy_create_config_space(mdev_state);
	mdpy_reset(mdev);

	mdpy_count++;
	return 0;
}

static int mdpy_remove(struct mdev_device *mdev)
{
	struct mdev_state *mdev_state = mdev_get_drvdata(mdev);
	struct device *dev = mdev_dev(mdev);

	dev_info(dev, "%s\n", __func__);

	mdev_set_drvdata(mdev, NULL);
	vfree(mdev_state->memblk);
	kfree(mdev_state->vconfig);
	kfree(mdev_state);

	mdpy_count--;
	return 0;
}

static ssize_t mdpy_read(struct mdev_device *mdev, char __user *buf,
			 size_t count, loff_t *ppos)
{
	unsigned int done = 0;
	int ret;

	while (count) {
		size_t filled;

		if (count >= 4 && !(*ppos % 4)) {
			u32 val;

			ret =  mdev_access(mdev, (char *)&val, sizeof(val),
					   *ppos, false);
			if (ret <= 0)
				goto read_err;

			if (copy_to_user(buf, &val, sizeof(val)))
				goto read_err;

			filled = 4;
		} else if (count >= 2 && !(*ppos % 2)) {
			u16 val;

			ret = mdev_access(mdev, (char *)&val, sizeof(val),
					  *ppos, false);
			if (ret <= 0)
				goto read_err;

			if (copy_to_user(buf, &val, sizeof(val)))
				goto read_err;

			filled = 2;
		} else {
			u8 val;

			ret = mdev_access(mdev, (char *)&val, sizeof(val),
					  *ppos, false);
			if (ret <= 0)
				goto read_err;

			if (copy_to_user(buf, &val, sizeof(val)))
				goto read_err;

			filled = 1;
		}

		count -= filled;
		done += filled;
		*ppos += filled;
		buf += filled;
	}

	return done;

read_err:
	return -EFAULT;
}

static ssize_t mdpy_write(struct mdev_device *mdev, const char __user *buf,
			  size_t count, loff_t *ppos)
{
	unsigned int done = 0;
	int ret;

	while (count) {
		size_t filled;

		if (count >= 4 && !(*ppos % 4)) {
			u32 val;

			if (copy_from_user(&val, buf, sizeof(val)))
				goto write_err;

			ret = mdev_access(mdev, (char *)&val, sizeof(val),
					  *ppos, true);
			if (ret <= 0)
				goto write_err;

			filled = 4;
		} else if (count >= 2 && !(*ppos % 2)) {
			u16 val;

			if (copy_from_user(&val, buf, sizeof(val)))
				goto write_err;

			ret = mdev_access(mdev, (char *)&val, sizeof(val),
					  *ppos, true);
			if (ret <= 0)
				goto write_err;

			filled = 2;
		} else {
			u8 val;

			if (copy_from_user(&val, buf, sizeof(val)))
				goto write_err;

			ret = mdev_access(mdev, (char *)&val, sizeof(val),
					  *ppos, true);
			if (ret <= 0)
				goto write_err;

			filled = 1;
		}
		count -= filled;
		done += filled;
		*ppos += filled;
		buf += filled;
	}

	return done;
write_err:
	return -EFAULT;
}

static int mdpy_mmap(struct mdev_device *mdev, struct vm_area_struct *vma)
{
	struct mdev_state *mdev_state = mdev_get_drvdata(mdev);

	if (vma->vm_pgoff != MDPY_MEMORY_BAR_OFFSET >> PAGE_SHIFT)
		return -EINVAL;
	if (vma->vm_end < vma->vm_start)
		return -EINVAL;
	if (vma->vm_end - vma->vm_start > mdev_state->memsize)
		return -EINVAL;
	if ((vma->vm_flags & VM_SHARED) == 0)
		return -EINVAL;

	return remap_vmalloc_range_partial(vma, vma->vm_start,
					   mdev_state->memblk,
					   vma->vm_end - vma->vm_start);
}

static int mdpy_get_region_info(struct mdev_device *mdev,
				struct vfio_region_info *region_info,
				u16 *cap_type_id, void **cap_type)
{
	struct mdev_state *mdev_state;

	mdev_state = mdev_get_drvdata(mdev);
	if (!mdev_state)
		return -EINVAL;

	if (region_info->index >= VFIO_PCI_NUM_REGIONS &&
	    region_info->index != MDPY_DISPLAY_REGION)
		return -EINVAL;

	switch (region_info->index) {
	case VFIO_PCI_CONFIG_REGION_INDEX:
		region_info->offset = 0;
		region_info->size   = MDPY_CONFIG_SPACE_SIZE;
		region_info->flags  = (VFIO_REGION_INFO_FLAG_READ |
				       VFIO_REGION_INFO_FLAG_WRITE);
		break;
	case VFIO_PCI_BAR0_REGION_INDEX:
	case MDPY_DISPLAY_REGION:
		region_info->offset = MDPY_MEMORY_BAR_OFFSET;
		region_info->size   = mdev_state->memsize;
		region_info->flags  = (VFIO_REGION_INFO_FLAG_READ  |
				       VFIO_REGION_INFO_FLAG_WRITE |
				       VFIO_REGION_INFO_FLAG_MMAP);
		break;
	default:
		region_info->size   = 0;
		region_info->offset = 0;
		region_info->flags  = 0;
	}

	return 0;
}

static int mdpy_get_irq_info(struct mdev_device *mdev,
			     struct vfio_irq_info *irq_info)
{
	irq_info->count = 0;
	return 0;
}

static int mdpy_get_device_info(struct mdev_device *mdev,
				struct vfio_device_info *dev_info)
{
	dev_info->flags = VFIO_DEVICE_FLAGS_PCI;
	dev_info->num_regions = VFIO_PCI_NUM_REGIONS;
	dev_info->num_irqs = VFIO_PCI_NUM_IRQS;
	return 0;
}

static int mdpy_query_gfx_plane(struct mdev_device *mdev,
				struct vfio_device_gfx_plane_info *plane)
{
	struct mdev_state *mdev_state = mdev_get_drvdata(mdev);

	if (plane->flags & VFIO_GFX_PLANE_TYPE_PROBE) {
		if (plane->flags == (VFIO_GFX_PLANE_TYPE_PROBE |
				     VFIO_GFX_PLANE_TYPE_REGION))
			return 0;
		return -EINVAL;
	}

	if (plane->flags != VFIO_GFX_PLANE_TYPE_REGION)
		return -EINVAL;

	plane->drm_format     = mdev_state->type->format;
	plane->width	      = mdev_state->type->width;
	plane->height	      = mdev_state->type->height;
	plane->stride	      = (mdev_state->type->width *
				 mdev_state->type->bytepp);
	plane->size	      = mdev_state->memsize;
	plane->region_index   = MDPY_DISPLAY_REGION;

	/* unused */
	plane->drm_format_mod = 0;
	plane->x_pos	      = 0;
	plane->y_pos	      = 0;
	plane->x_hot	      = 0;
	plane->y_hot	      = 0;

	return 0;
}

static long mdpy_ioctl(struct mdev_device *mdev, unsigned int cmd,
		       unsigned long arg)
{
	int ret = 0;
	unsigned long minsz;
	struct mdev_state *mdev_state;

	mdev_state = mdev_get_drvdata(mdev);

	switch (cmd) {
	case VFIO_DEVICE_GET_INFO:
	{
		struct vfio_device_info info;

		minsz = offsetofend(struct vfio_device_info, num_irqs);

		if (copy_from_user(&info, (void __user *)arg, minsz))
			return -EFAULT;

		if (info.argsz < minsz)
			return -EINVAL;

		ret = mdpy_get_device_info(mdev, &info);
		if (ret)
			return ret;

		memcpy(&mdev_state->dev_info, &info, sizeof(info));

		if (copy_to_user((void __user *)arg, &info, minsz))
			return -EFAULT;

		return 0;
	}
	case VFIO_DEVICE_GET_REGION_INFO:
	{
		struct vfio_region_info info;
		u16 cap_type_id = 0;
		void *cap_type = NULL;

		minsz = offsetofend(struct vfio_region_info, offset);

		if (copy_from_user(&info, (void __user *)arg, minsz))
			return -EFAULT;

		if (info.argsz < minsz)
			return -EINVAL;

		ret = mdpy_get_region_info(mdev, &info, &cap_type_id,
					   &cap_type);
		if (ret)
			return ret;

		if (copy_to_user((void __user *)arg, &info, minsz))
			return -EFAULT;

		return 0;
	}

	case VFIO_DEVICE_GET_IRQ_INFO:
	{
		struct vfio_irq_info info;

		minsz = offsetofend(struct vfio_irq_info, count);

		if (copy_from_user(&info, (void __user *)arg, minsz))
			return -EFAULT;

		if ((info.argsz < minsz) ||
		    (info.index >= mdev_state->dev_info.num_irqs))
			return -EINVAL;

		ret = mdpy_get_irq_info(mdev, &info);
		if (ret)
			return ret;

		if (copy_to_user((void __user *)arg, &info, minsz))
			return -EFAULT;

		return 0;
	}

	case VFIO_DEVICE_QUERY_GFX_PLANE:
	{
		struct vfio_device_gfx_plane_info plane;

		minsz = offsetofend(struct vfio_device_gfx_plane_info,
				    region_index);

		if (copy_from_user(&plane, (void __user *)arg, minsz))
			return -EFAULT;

		if (plane.argsz < minsz)
			return -EINVAL;

		ret = mdpy_query_gfx_plane(mdev, &plane);
		if (ret)
			return ret;

		if (copy_to_user((void __user *)arg, &plane, minsz))
			return -EFAULT;

		return 0;
	}

	case VFIO_DEVICE_SET_IRQS:
		return -EINVAL;

	case VFIO_DEVICE_RESET:
		return mdpy_reset(mdev);
	}
	return -ENOTTY;
}

static int mdpy_open(struct mdev_device *mdev)
{
	if (!try_module_get(THIS_MODULE))
		return -ENODEV;

	return 0;
}

static void mdpy_close(struct mdev_device *mdev)
{
	module_put(THIS_MODULE);
}

static ssize_t
resolution_show(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	struct mdev_device *mdev = mdev_from_dev(dev);
	struct mdev_state *mdev_state = mdev_get_drvdata(mdev);

	return sprintf(buf, "%dx%d\n",
		       mdev_state->type->width,
		       mdev_state->type->height);
}
static DEVICE_ATTR_RO(resolution);

static struct attribute *mdev_dev_attrs[] = {
	&dev_attr_resolution.attr,
	NULL,
};

static const struct attribute_group mdev_dev_group = {
	.name  = "vendor",
	.attrs = mdev_dev_attrs,
};

const struct attribute_group *mdev_dev_groups[] = {
	&mdev_dev_group,
	NULL,
};

static ssize_t
name_show(struct kobject *kobj, struct device *dev, char *buf)
{
	return sprintf(buf, "%s\n", kobj->name);
}
MDEV_TYPE_ATTR_RO(name);

static ssize_t
description_show(struct kobject *kobj, struct device *dev, char *buf)
{
	const struct mdpy_type *type = mdpy_find_type(kobj);

	return sprintf(buf, "virtual display, %dx%d framebuffer\n",
		       type ? type->width  : 0,
		       type ? type->height : 0);
}
MDEV_TYPE_ATTR_RO(description);

static ssize_t
available_instances_show(struct kobject *kobj, struct device *dev, char *buf)
{
	return sprintf(buf, "%d\n", max_devices - mdpy_count);
}
MDEV_TYPE_ATTR_RO(available_instances);

static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
			       char *buf)
{
	return sprintf(buf, "%s\n", VFIO_DEVICE_API_PCI_STRING);
}
MDEV_TYPE_ATTR_RO(device_api);

static struct attribute *mdev_types_attrs[] = {
	&mdev_type_attr_name.attr,
	&mdev_type_attr_description.attr,
	&mdev_type_attr_device_api.attr,
	&mdev_type_attr_available_instances.attr,
	NULL,
};

static struct attribute_group mdev_type_group1 = {
	.name  = MDPY_TYPE_1,
	.attrs = mdev_types_attrs,
};

static struct attribute_group mdev_type_group2 = {
	.name  = MDPY_TYPE_2,
	.attrs = mdev_types_attrs,
};

static struct attribute_group mdev_type_group3 = {
	.name  = MDPY_TYPE_3,
	.attrs = mdev_types_attrs,
};

static struct attribute_group *mdev_type_groups[] = {
	&mdev_type_group1,
	&mdev_type_group2,
	&mdev_type_group3,
	NULL,
};

static const struct mdev_parent_ops mdev_fops = {
	.owner			= THIS_MODULE,
	.mdev_attr_groups	= mdev_dev_groups,
	.supported_type_groups	= mdev_type_groups,
	.create			= mdpy_create,
	.remove			= mdpy_remove,
	.open			= mdpy_open,
	.release		= mdpy_close,
	.read			= mdpy_read,
	.write			= mdpy_write,
	.ioctl			= mdpy_ioctl,
	.mmap			= mdpy_mmap,
};

static const struct file_operations vd_fops = {
	.owner		= THIS_MODULE,
};

static void mdpy_device_release(struct device *dev)
{
	/* nothing */
}

static int __init mdpy_dev_init(void)
{
	int ret = 0;

	ret = alloc_chrdev_region(&mdpy_devt, 0, MINORMASK, MDPY_NAME);
	if (ret < 0) {
		pr_err("Error: failed to register mdpy_dev, err: %d\n", ret);
		return ret;
	}
	cdev_init(&mdpy_cdev, &vd_fops);
	cdev_add(&mdpy_cdev, mdpy_devt, MINORMASK);
	pr_info("%s: major %d\n", __func__, MAJOR(mdpy_devt));

	mdpy_class = class_create(THIS_MODULE, MDPY_CLASS_NAME);
	if (IS_ERR(mdpy_class)) {
		pr_err("Error: failed to register mdpy_dev class\n");
		ret = PTR_ERR(mdpy_class);
		goto failed1;
	}
	mdpy_dev.class = mdpy_class;
	mdpy_dev.release = mdpy_device_release;
	dev_set_name(&mdpy_dev, "%s", MDPY_NAME);

	ret = device_register(&mdpy_dev);
	if (ret)
		goto failed2;

	ret = mdev_register_device(&mdpy_dev, &mdev_fops);
	if (ret)
		goto failed3;

	return 0;

failed3:
	device_unregister(&mdpy_dev);
failed2:
	class_destroy(mdpy_class);
failed1:
	cdev_del(&mdpy_cdev);
	unregister_chrdev_region(mdpy_devt, MINORMASK);
	return ret;
}

static void __exit mdpy_dev_exit(void)
{
	mdpy_dev.bus = NULL;
	mdev_unregister_device(&mdpy_dev);

	device_unregister(&mdpy_dev);
	cdev_del(&mdpy_cdev);
	unregister_chrdev_region(mdpy_devt, MINORMASK);
	class_destroy(mdpy_class);
	mdpy_class = NULL;
}

module_init(mdpy_dev_init)
module_exit(mdpy_dev_exit)
Commit	Line	Data
d61fc96f GH	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* Mediated virtual PCI display host device driver
	4	*
	5	* See mdpy-defs.h for device specs
	6	*
	7	* (c) Gerd Hoffmann <[email protected]>
	8	*
	9	* based on mtty driver which is:
	10	* Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
	11	* Author: Neo Jia <[email protected]>
	12	* Kirti Wankhede <[email protected]>
	13	*
	14	* This program is free software; you can redistribute it and/or modify
	15	* it under the terms of the GNU General Public License version 2 as
	16	* published by the Free Software Foundation.
	17	*/
	18	#include <linux/init.h>
	19	#include <linux/module.h>
	20	#include <linux/device.h>
	21	#include <linux/kernel.h>
	22	#include <linux/slab.h>
	23	#include <linux/vmalloc.h>
	24	#include <linux/cdev.h>
	25	#include <linux/vfio.h>
	26	#include <linux/iommu.h>
	27	#include <linux/sysfs.h>
	28	#include <linux/mdev.h>
	29	#include <linux/pci.h>
	30	#include <drm/drm_fourcc.h>
	31	#include "mdpy-defs.h"
	32
	33	#define MDPY_NAME "mdpy"
	34	#define MDPY_CLASS_NAME "mdpy"
	35
	36	#define MDPY_CONFIG_SPACE_SIZE 0xff
	37	#define MDPY_MEMORY_BAR_OFFSET PAGE_SIZE
	38	#define MDPY_DISPLAY_REGION 16
	39
	40	#define STORE_LE16(addr, val) ((u16 )addr = val)
	41	#define STORE_LE32(addr, val) ((u32 )addr = val)
	42
	43
	44	MODULE_LICENSE("GPL v2");
	45
	46	static int max_devices = 4;
	47	module_param_named(count, max_devices, int, 0444);
	48	MODULE_PARM_DESC(count, "number of " MDPY_NAME " devices");
	49
	50
	51	#define MDPY_TYPE_1 "vga"
	52	#define MDPY_TYPE_2 "xga"
	53	#define MDPY_TYPE_3 "hd"
	54
	55	static const struct mdpy_type {
	56	const char *name;
	57	u32 format;
	58	u32 bytepp;
	59	u32 width;
	60	u32 height;
	61	} mdpy_types[] = {
	62	{
	63	.name = MDPY_CLASS_NAME "-" MDPY_TYPE_1,
	64	.format = DRM_FORMAT_XRGB8888,
65	.bytepp = 4,
66	.width = 640,
67	.height = 480,
68	}, {
69	.name = MDPY_CLASS_NAME "-" MDPY_TYPE_2,
70	.format = DRM_FORMAT_XRGB8888,
71	.bytepp = 4,
72	.width = 1024,
73	.height = 768,
74	}, {
75	.name = MDPY_CLASS_NAME "-" MDPY_TYPE_3,
76	.format = DRM_FORMAT_XRGB8888,
77	.bytepp = 4,
78	.width = 1920,
79	.height = 1080,
80	},
81	};
82
83	static dev_t mdpy_devt;
84	static struct class *mdpy_class;
85	static struct cdev mdpy_cdev;
86	static struct device mdpy_dev;
87	static u32 mdpy_count;
88
89	/* State of each mdev device */
90	struct mdev_state {
91	u8 *vconfig;
92	u32 bar_mask;
93	struct mutex ops_lock;
94	struct mdev_device *mdev;
95	struct vfio_device_info dev_info;
96
97	const struct mdpy_type *type;
98	u32 memsize;
99	void *memblk;
100	};
101
102	static const struct mdpy_type mdpy_find_type(struct kobject kobj)
103	{
104	int i;
105
106	for (i = 0; i < ARRAY_SIZE(mdpy_types); i++)
107	if (strcmp(mdpy_types[i].name, kobj->name) == 0)
108	return mdpy_types + i;
109	return NULL;
110	}
111
112	static void mdpy_create_config_space(struct mdev_state *mdev_state)
113	{
114	STORE_LE16((u16 *) &mdev_state->vconfig[PCI_VENDOR_ID],
115	MDPY_PCI_VENDOR_ID);
116	STORE_LE16((u16 *) &mdev_state->vconfig[PCI_DEVICE_ID],
117	MDPY_PCI_DEVICE_ID);
118	STORE_LE16((u16 *) &mdev_state->vconfig[PCI_SUBSYSTEM_VENDOR_ID],
119	MDPY_PCI_SUBVENDOR_ID);
120	STORE_LE16((u16 *) &mdev_state->vconfig[PCI_SUBSYSTEM_ID],
121	MDPY_PCI_SUBDEVICE_ID);
122
123	STORE_LE16((u16 *) &mdev_state->vconfig[PCI_COMMAND],
124	PCI_COMMAND_IO \| PCI_COMMAND_MEMORY);
125	STORE_LE16((u16 *) &mdev_state->vconfig[PCI_STATUS],
126	PCI_STATUS_CAP_LIST);
127	STORE_LE16((u16 *) &mdev_state->vconfig[PCI_CLASS_DEVICE],
128	PCI_CLASS_DISPLAY_OTHER);
129	mdev_state->vconfig[PCI_CLASS_REVISION] = 0x01;
130
131	STORE_LE32((u32 *) &mdev_state->vconfig[PCI_BASE_ADDRESS_0],
132	PCI_BASE_ADDRESS_SPACE_MEMORY \|
133	PCI_BASE_ADDRESS_MEM_TYPE_32 \|
134	PCI_BASE_ADDRESS_MEM_PREFETCH);
135	mdev_state->bar_mask = ~(mdev_state->memsize) + 1;
136
137	/* vendor specific capability for the config registers */
138	mdev_state->vconfig[PCI_CAPABILITY_LIST] = MDPY_VENDORCAP_OFFSET;
139	mdev_state->vconfig[MDPY_VENDORCAP_OFFSET + 0] = 0x09; /* vendor cap */
140	mdev_state->vconfig[MDPY_VENDORCAP_OFFSET + 1] = 0x00; /* next ptr */
141	mdev_state->vconfig[MDPY_VENDORCAP_OFFSET + 2] = MDPY_VENDORCAP_SIZE;
142	STORE_LE32((u32 *) &mdev_state->vconfig[MDPY_FORMAT_OFFSET],
143	mdev_state->type->format);
144	STORE_LE32((u32 *) &mdev_state->vconfig[MDPY_WIDTH_OFFSET],
145	mdev_state->type->width);
146	STORE_LE32((u32 *) &mdev_state->vconfig[MDPY_HEIGHT_OFFSET],
147	mdev_state->type->height);
148	}
149
150	static void handle_pci_cfg_write(struct mdev_state *mdev_state, u16 offset,
151	char *buf, u32 count)
152	{
153	struct device *dev = mdev_dev(mdev_state->mdev);
154	u32 cfg_addr;
155
156	switch (offset) {
157	case PCI_BASE_ADDRESS_0:
158	cfg_addr = (u32 )buf;
159
160	if (cfg_addr == 0xffffffff) {
161	cfg_addr = (cfg_addr & mdev_state->bar_mask);
162	} else {
163	cfg_addr &= PCI_BASE_ADDRESS_MEM_MASK;
164	if (cfg_addr)
165	dev_info(dev, "BAR0 @ 0x%x\n", cfg_addr);
166	}
167
168	cfg_addr \|= (mdev_state->vconfig[offset] &
169	~PCI_BASE_ADDRESS_MEM_MASK);
170	STORE_LE32(&mdev_state->vconfig[offset], cfg_addr);
171	break;
172	}
173	}
174
175	static ssize_t mdev_access(struct mdev_device mdev, char buf, size_t count,
176	loff_t pos, bool is_write)
177	{
178	struct mdev_state *mdev_state = mdev_get_drvdata(mdev);
179	struct device *dev = mdev_dev(mdev);
180	int ret = 0;
181
182	mutex_lock(&mdev_state->ops_lock);
183
184	if (pos < MDPY_CONFIG_SPACE_SIZE) {
185	if (is_write)
186	handle_pci_cfg_write(mdev_state, pos, buf, count);
187	else
188	memcpy(buf, (mdev_state->vconfig + pos), count);
189
190	} else if ((pos >= MDPY_MEMORY_BAR_OFFSET) &&
191	(pos + count <=
192	MDPY_MEMORY_BAR_OFFSET + mdev_state->memsize)) {
193	pos -= MDPY_MEMORY_BAR_OFFSET;
194	if (is_write)
195	memcpy(mdev_state->memblk, buf, count);
196	else
197	memcpy(buf, mdev_state->memblk, count);
198
199	} else {
200	dev_info(dev, "%s: %s @0x%llx (unhandled)\n",
201	__func__, is_write ? "WR" : "RD", pos);
202	ret = -1;
203	goto accessfailed;
204	}
205
206	ret = count;
207
208
209	accessfailed:
210	mutex_unlock(&mdev_state->ops_lock);
211
212	return ret;
213	}
214
215	static int mdpy_reset(struct mdev_device *mdev)
216	{
217	struct mdev_state *mdev_state = mdev_get_drvdata(mdev);
218	u32 stride, i;
219
220	/* initialize with gray gradient */
221	stride = mdev_state->type->width * mdev_state->type->bytepp;
222	for (i = 0; i < mdev_state->type->height; i++)
223	memset(mdev_state->memblk + i * stride,
224	i * 255 / mdev_state->type->height,
225	stride);
226	return 0;
227	}
228
229	static int mdpy_create(struct kobject kobj, struct mdev_device mdev)
230	{
231	const struct mdpy_type *type = mdpy_find_type(kobj);
232	struct device *dev = mdev_dev(mdev);
233	struct mdev_state *mdev_state;
234	u32 fbsize;
235
236	if (mdpy_count >= max_devices)
237	return -ENOMEM;
238
239	mdev_state = kzalloc(sizeof(struct mdev_state), GFP_KERNEL);
240	if (mdev_state == NULL)
241	return -ENOMEM;
242
243	mdev_state->vconfig = kzalloc(MDPY_CONFIG_SPACE_SIZE, GFP_KERNEL);
244	if (mdev_state->vconfig == NULL) {
245	kfree(mdev_state);
246	return -ENOMEM;
247	}
248
249	if (!type)
250	type = &mdpy_types[0];
251	fbsize = roundup_pow_of_two(type->width * type->height * type->bytepp);
252
253	mdev_state->memblk = vmalloc_user(fbsize);
254	if (!mdev_state->memblk) {
255	kfree(mdev_state->vconfig);
256	kfree(mdev_state);
257	return -ENOMEM;
258	}
259	dev_info(dev, "%s: %s (%dx%d)\n",
260	__func__, kobj->name, type->width, type->height);
261
262	mutex_init(&mdev_state->ops_lock);
263	mdev_state->mdev = mdev;
264	mdev_set_drvdata(mdev, mdev_state);
265
266	mdev_state->type = type;
267	mdev_state->memsize = fbsize;
268	mdpy_create_config_space(mdev_state);
269	mdpy_reset(mdev);
270
271	mdpy_count++;
272	return 0;
273	}
274
275	static int mdpy_remove(struct mdev_device *mdev)
276	{
277	struct mdev_state *mdev_state = mdev_get_drvdata(mdev);
278	struct device *dev = mdev_dev(mdev);
279
280	dev_info(dev, "%s\n", __func__);
281
282	mdev_set_drvdata(mdev, NULL);
283	vfree(mdev_state->memblk);
284	kfree(mdev_state->vconfig);
285	kfree(mdev_state);
286
287	mdpy_count--;
288	return 0;
289	}
290
291	static ssize_t mdpy_read(struct mdev_device mdev, char __user buf,
292	size_t count, loff_t *ppos)
293	{
294	unsigned int done = 0;
295	int ret;
296
297	while (count) {
298	size_t filled;
299
300	if (count >= 4 && !(*ppos % 4)) {
301	u32 val;
302
303	ret = mdev_access(mdev, (char *)&val, sizeof(val),
304	*ppos, false);
305	if (ret <= 0)
306	goto read_err;
307
308	if (copy_to_user(buf, &val, sizeof(val)))
309	goto read_err;
310
311	filled = 4;
312	} else if (count >= 2 && !(*ppos % 2)) {
313	u16 val;
314
315	ret = mdev_access(mdev, (char *)&val, sizeof(val),
316	*ppos, false);
317	if (ret <= 0)
318	goto read_err;
319
320	if (copy_to_user(buf, &val, sizeof(val)))
321	goto read_err;
322
323	filled = 2;
324	} else {
325	u8 val;
326
327	ret = mdev_access(mdev, (char *)&val, sizeof(val),
328	*ppos, false);
329	if (ret <= 0)
330	goto read_err;
331
332	if (copy_to_user(buf, &val, sizeof(val)))
333	goto read_err;
334
335	filled = 1;
336	}
337
338	count -= filled;
339	done += filled;
340	*ppos += filled;
341	buf += filled;
342	}
343
344	return done;
345
346	read_err:
347	return -EFAULT;
348	}
349
350	static ssize_t mdpy_write(struct mdev_device mdev, const char __user buf,
351	size_t count, loff_t *ppos)
352	{
353	unsigned int done = 0;
354	int ret;
355
356	while (count) {
357	size_t filled;
358
359	if (count >= 4 && !(*ppos % 4)) {
360	u32 val;
361
362	if (copy_from_user(&val, buf, sizeof(val)))
363	goto write_err;
364
365	ret = mdev_access(mdev, (char *)&val, sizeof(val),
366	*ppos, true);
367	if (ret <= 0)
368	goto write_err;
369
370	filled = 4;
371	} else if (count >= 2 && !(*ppos % 2)) {
372	u16 val;
373
374	if (copy_from_user(&val, buf, sizeof(val)))
375	goto write_err;
376
377	ret = mdev_access(mdev, (char *)&val, sizeof(val),
378	*ppos, true);
379	if (ret <= 0)
380	goto write_err;
381
382	filled = 2;
383	} else {
384	u8 val;
385
386	if (copy_from_user(&val, buf, sizeof(val)))
387	goto write_err;
388
389	ret = mdev_access(mdev, (char *)&val, sizeof(val),
390	*ppos, true);
391	if (ret <= 0)
392	goto write_err;
393
394	filled = 1;
395	}
396	count -= filled;
397	done += filled;
398	*ppos += filled;
399	buf += filled;
400	}
401
402	return done;
403	write_err:
404	return -EFAULT;
405	}
406
407	static int mdpy_mmap(struct mdev_device mdev, struct vm_area_struct vma)
408	{
409	struct mdev_state *mdev_state = mdev_get_drvdata(mdev);
410
411	if (vma->vm_pgoff != MDPY_MEMORY_BAR_OFFSET >> PAGE_SHIFT)
412	return -EINVAL;
413	if (vma->vm_end < vma->vm_start)
414	return -EINVAL;
415	if (vma->vm_end - vma->vm_start > mdev_state->memsize)
416	return -EINVAL;
417	if ((vma->vm_flags & VM_SHARED) == 0)
418	return -EINVAL;
419
420	return remap_vmalloc_range_partial(vma, vma->vm_start,
421	mdev_state->memblk,
422	vma->vm_end - vma->vm_start);
423	}
424
425	static int mdpy_get_region_info(struct mdev_device *mdev,
426	struct vfio_region_info *region_info,
427	u16 cap_type_id, void *cap_type)
428	{
429	struct mdev_state *mdev_state;
430
431	mdev_state = mdev_get_drvdata(mdev);
432	if (!mdev_state)
433	return -EINVAL;
434
435	if (region_info->index >= VFIO_PCI_NUM_REGIONS &&
436	region_info->index != MDPY_DISPLAY_REGION)
437	return -EINVAL;
438
439	switch (region_info->index) {
440	case VFIO_PCI_CONFIG_REGION_INDEX:
441	region_info->offset = 0;
442	region_info->size = MDPY_CONFIG_SPACE_SIZE;
443	region_info->flags = (VFIO_REGION_INFO_FLAG_READ \|
444	VFIO_REGION_INFO_FLAG_WRITE);
445	break;
446	case VFIO_PCI_BAR0_REGION_INDEX:
447	case MDPY_DISPLAY_REGION:
448	region_info->offset = MDPY_MEMORY_BAR_OFFSET;
449	region_info->size = mdev_state->memsize;
450	region_info->flags = (VFIO_REGION_INFO_FLAG_READ \|
451	VFIO_REGION_INFO_FLAG_WRITE \|
452	VFIO_REGION_INFO_FLAG_MMAP);
453	break;
454	default:
455	region_info->size = 0;
456	region_info->offset = 0;
457	region_info->flags = 0;
458	}
459
460	return 0;
461	}
462
463	static int mdpy_get_irq_info(struct mdev_device *mdev,
464	struct vfio_irq_info *irq_info)
465	{
466	irq_info->count = 0;
467	return 0;
468	}
469
470	static int mdpy_get_device_info(struct mdev_device *mdev,
471	struct vfio_device_info *dev_info)
472	{
473	dev_info->flags = VFIO_DEVICE_FLAGS_PCI;
474	dev_info->num_regions = VFIO_PCI_NUM_REGIONS;
475	dev_info->num_irqs = VFIO_PCI_NUM_IRQS;
476	return 0;
477	}
478
479	static int mdpy_query_gfx_plane(struct mdev_device *mdev,
480	struct vfio_device_gfx_plane_info *plane)
481	{
482	struct mdev_state *mdev_state = mdev_get_drvdata(mdev);
483
484	if (plane->flags & VFIO_GFX_PLANE_TYPE_PROBE) {
485	if (plane->flags == (VFIO_GFX_PLANE_TYPE_PROBE \|
486	VFIO_GFX_PLANE_TYPE_REGION))
487	return 0;
488	return -EINVAL;
489	}
490
491	if (plane->flags != VFIO_GFX_PLANE_TYPE_REGION)
492	return -EINVAL;
493
494	plane->drm_format = mdev_state->type->format;
495	plane->width = mdev_state->type->width;
496	plane->height = mdev_state->type->height;
497	plane->stride = (mdev_state->type->width *
498	mdev_state->type->bytepp);
499	plane->size = mdev_state->memsize;
500	plane->region_index = MDPY_DISPLAY_REGION;
501
502	/* unused */
503	plane->drm_format_mod = 0;
504	plane->x_pos = 0;
505	plane->y_pos = 0;
506	plane->x_hot = 0;
507	plane->y_hot = 0;
508
509	return 0;
510	}
511
512	static long mdpy_ioctl(struct mdev_device *mdev, unsigned int cmd,
513	unsigned long arg)
514	{
515	int ret = 0;
516	unsigned long minsz;
517	struct mdev_state *mdev_state;
518
519	mdev_state = mdev_get_drvdata(mdev);
520
521	switch (cmd) {
522	case VFIO_DEVICE_GET_INFO:
523	{
524	struct vfio_device_info info;
525
526	minsz = offsetofend(struct vfio_device_info, num_irqs);
527
528	if (copy_from_user(&info, (void __user *)arg, minsz))
529	return -EFAULT;
530
531	if (info.argsz < minsz)
532	return -EINVAL;
533
534	ret = mdpy_get_device_info(mdev, &info);
535	if (ret)
536	return ret;
537
538	memcpy(&mdev_state->dev_info, &info, sizeof(info));
539
540	if (copy_to_user((void __user *)arg, &info, minsz))
541	return -EFAULT;
542
543	return 0;
544	}
545	case VFIO_DEVICE_GET_REGION_INFO:
546	{
547	struct vfio_region_info info;
548	u16 cap_type_id = 0;
549	void *cap_type = NULL;
550
551	minsz = offsetofend(struct vfio_region_info, offset);
552
553	if (copy_from_user(&info, (void __user *)arg, minsz))
554	return -EFAULT;
555
556	if (info.argsz < minsz)
557	return -EINVAL;
558
559	ret = mdpy_get_region_info(mdev, &info, &cap_type_id,
560	&cap_type);
561	if (ret)
562	return ret;
563
564	if (copy_to_user((void __user *)arg, &info, minsz))
565	return -EFAULT;
566
567	return 0;
568	}
569
570	case VFIO_DEVICE_GET_IRQ_INFO:
571	{
572	struct vfio_irq_info info;
573
574	minsz = offsetofend(struct vfio_irq_info, count);
575
576	if (copy_from_user(&info, (void __user *)arg, minsz))
577	return -EFAULT;
578
579	if ((info.argsz < minsz) \|\|
580	(info.index >= mdev_state->dev_info.num_irqs))
581	return -EINVAL;
582
583	ret = mdpy_get_irq_info(mdev, &info);
584	if (ret)
585	return ret;
586
587	if (copy_to_user((void __user *)arg, &info, minsz))
588	return -EFAULT;
589
590	return 0;
591	}
592
593	case VFIO_DEVICE_QUERY_GFX_PLANE:
594	{
595	struct vfio_device_gfx_plane_info plane;
596
597	minsz = offsetofend(struct vfio_device_gfx_plane_info,
598	region_index);
599
600	if (copy_from_user(&plane, (void __user *)arg, minsz))
601	return -EFAULT;
602
603	if (plane.argsz < minsz)
604	return -EINVAL;
605
606	ret = mdpy_query_gfx_plane(mdev, &plane);
607	if (ret)
608	return ret;
609
610	if (copy_to_user((void __user *)arg, &plane, minsz))
611	return -EFAULT;
612
613	return 0;
614	}
615
616	case VFIO_DEVICE_SET_IRQS:
617	return -EINVAL;
618
619	case VFIO_DEVICE_RESET:
620	return mdpy_reset(mdev);
621	}
622	return -ENOTTY;
623	}
624
625	static int mdpy_open(struct mdev_device *mdev)
626	{
627	if (!try_module_get(THIS_MODULE))
628	return -ENODEV;
629
630	return 0;
631	}
632
633	static void mdpy_close(struct mdev_device *mdev)
634	{
635	module_put(THIS_MODULE);
636	}
637
638	static ssize_t
639	resolution_show(struct device dev, struct device_attribute attr,
640	char *buf)
641	{
642	struct mdev_device *mdev = mdev_from_dev(dev);
643	struct mdev_state *mdev_state = mdev_get_drvdata(mdev);
644
645	return sprintf(buf, "%dx%d\n",
646	mdev_state->type->width,
647	mdev_state->type->height);
648	}
649	static DEVICE_ATTR_RO(resolution);
650
651	static struct attribute *mdev_dev_attrs[] = {
652	&dev_attr_resolution.attr,
653	NULL,
654	};
655
656	static const struct attribute_group mdev_dev_group = {
657	.name = "vendor",
658	.attrs = mdev_dev_attrs,
659	};
660
661	const struct attribute_group *mdev_dev_groups[] = {
662	&mdev_dev_group,
663	NULL,
664	};
665
666	static ssize_t
667	name_show(struct kobject kobj, struct device dev, char *buf)
668	{
669	return sprintf(buf, "%s\n", kobj->name);
670	}
671	MDEV_TYPE_ATTR_RO(name);
672
673	static ssize_t
674	description_show(struct kobject kobj, struct device dev, char *buf)
675	{
676	const struct mdpy_type *type = mdpy_find_type(kobj);
677
678	return sprintf(buf, "virtual display, %dx%d framebuffer\n",
679	type ? type->width : 0,
680	type ? type->height : 0);
681	}
682	MDEV_TYPE_ATTR_RO(description);
683
684	static ssize_t
685	available_instances_show(struct kobject kobj, struct device dev, char *buf)
686	{
687	return sprintf(buf, "%d\n", max_devices - mdpy_count);
688	}
689	MDEV_TYPE_ATTR_RO(available_instances);
690
691	static ssize_t device_api_show(struct kobject kobj, struct device dev,
692	char *buf)
693	{
694	return sprintf(buf, "%s\n", VFIO_DEVICE_API_PCI_STRING);
695	}
696	MDEV_TYPE_ATTR_RO(device_api);
697
698	static struct attribute *mdev_types_attrs[] = {
699	&mdev_type_attr_name.attr,
700	&mdev_type_attr_description.attr,
701	&mdev_type_attr_device_api.attr,
702	&mdev_type_attr_available_instances.attr,
703	NULL,
704	};
705
706	static struct attribute_group mdev_type_group1 = {
707	.name = MDPY_TYPE_1,
708	.attrs = mdev_types_attrs,
709	};
710
711	static struct attribute_group mdev_type_group2 = {
712	.name = MDPY_TYPE_2,
713	.attrs = mdev_types_attrs,
714	};
715
716	static struct attribute_group mdev_type_group3 = {
717	.name = MDPY_TYPE_3,
718	.attrs = mdev_types_attrs,
719	};
720
721	static struct attribute_group *mdev_type_groups[] = {
722	&mdev_type_group1,
723	&mdev_type_group2,
724	&mdev_type_group3,
725	NULL,
726	};
727
728	static const struct mdev_parent_ops mdev_fops = {
729	.owner = THIS_MODULE,
730	.mdev_attr_groups = mdev_dev_groups,
731	.supported_type_groups = mdev_type_groups,
732	.create = mdpy_create,
733	.remove = mdpy_remove,
734	.open = mdpy_open,
735	.release = mdpy_close,
736	.read = mdpy_read,
737	.write = mdpy_write,
738	.ioctl = mdpy_ioctl,
739	.mmap = mdpy_mmap,
740	};
741
742	static const struct file_operations vd_fops = {
743	.owner = THIS_MODULE,
744	};
745
746	static void mdpy_device_release(struct device *dev)
747	{
748	/* nothing */
749	}
750
751	static int __init mdpy_dev_init(void)
752	{
753	int ret = 0;
754
755	ret = alloc_chrdev_region(&mdpy_devt, 0, MINORMASK, MDPY_NAME);
756	if (ret < 0) {
757	pr_err("Error: failed to register mdpy_dev, err: %d\n", ret);
758	return ret;
759	}
760	cdev_init(&mdpy_cdev, &vd_fops);
761	cdev_add(&mdpy_cdev, mdpy_devt, MINORMASK);
762	pr_info("%s: major %d\n", __func__, MAJOR(mdpy_devt));
763
764	mdpy_class = class_create(THIS_MODULE, MDPY_CLASS_NAME);
765	if (IS_ERR(mdpy_class)) {
766	pr_err("Error: failed to register mdpy_dev class\n");
767	ret = PTR_ERR(mdpy_class);
768	goto failed1;
769	}
770	mdpy_dev.class = mdpy_class;
771	mdpy_dev.release = mdpy_device_release;
772	dev_set_name(&mdpy_dev, "%s", MDPY_NAME);
773
774	ret = device_register(&mdpy_dev);
775	if (ret)
776	goto failed2;
777
778	ret = mdev_register_device(&mdpy_dev, &mdev_fops);
779	if (ret)
780	goto failed3;
781
782	return 0;
783
784	failed3:
785	device_unregister(&mdpy_dev);
786	failed2:
787	class_destroy(mdpy_class);
788	failed1:
789	cdev_del(&mdpy_cdev);
790	unregister_chrdev_region(mdpy_devt, MINORMASK);
791	return ret;
792	}
793
794	static void __exit mdpy_dev_exit(void)
795	{
796	mdpy_dev.bus = NULL;
797	mdev_unregister_device(&mdpy_dev);
798
799	device_unregister(&mdpy_dev);
800	cdev_del(&mdpy_cdev);
801	unregister_chrdev_region(mdpy_devt, MINORMASK);
802	class_destroy(mdpy_class);
803	mdpy_class = NULL;
804	}
805
806	module_init(mdpy_dev_init)
807	module_exit(mdpy_dev_exit)