[RFC PATCH 4/4] docs: Sample driver to demonstrate how to implement virtio-mdev framework

From: Jason Wang
Date: Tue Sep 10 2019 - 04:20:50 EST


This sample driver creates mdev device that simulate virtio net device
over virtio mdev transport. The device is implemented through vringh
and workqueue.

Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
samples/Kconfig | 7 +
samples/vfio-mdev/Makefile | 1 +
samples/vfio-mdev/mvnet.c | 766 +++++++++++++++++++++++++++++++++++++
3 files changed, 774 insertions(+)
create mode 100644 samples/vfio-mdev/mvnet.c

diff --git a/samples/Kconfig b/samples/Kconfig
index c8dacb4dda80..a1a1ca2c00b7 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -131,6 +131,13 @@ config SAMPLE_VFIO_MDEV_MDPY
mediated device. It is a simple framebuffer and supports
the region display interface (VFIO_GFX_PLANE_TYPE_REGION).

+config SAMPLE_VIRTIO_MDEV_NET
+ tristate "Build virtio mdev net example mediated device sample code -- loadable modules only"
+ depends on VIRTIO_MDEV_DEVICE && VHOST_RING && m
+ help
+ Build a networking sample device for use as a virtio
+ mediated device.
+
config SAMPLE_VFIO_MDEV_MDPY_FB
tristate "Build VFIO mdpy example guest fbdev driver -- loadable module only"
depends on FB && m
diff --git a/samples/vfio-mdev/Makefile b/samples/vfio-mdev/Makefile
index 10d179c4fdeb..f34af90ed0a0 100644
--- a/samples/vfio-mdev/Makefile
+++ b/samples/vfio-mdev/Makefile
@@ -3,3 +3,4 @@ obj-$(CONFIG_SAMPLE_VFIO_MDEV_MTTY) += mtty.o
obj-$(CONFIG_SAMPLE_VFIO_MDEV_MDPY) += mdpy.o
obj-$(CONFIG_SAMPLE_VFIO_MDEV_MDPY_FB) += mdpy-fb.o
obj-$(CONFIG_SAMPLE_VFIO_MDEV_MBOCHS) += mbochs.o
+obj-$(CONFIG_SAMPLE_VIRTIO_MDEV_NET) += mvnet.o
diff --git a/samples/vfio-mdev/mvnet.c b/samples/vfio-mdev/mvnet.c
new file mode 100644
index 000000000000..da295b41955e
--- /dev/null
+++ b/samples/vfio-mdev/mvnet.c
@@ -0,0 +1,766 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Mediated virtual virtio-net device driver.
+ *
+ * Copyright (c) 2019, Red Hat Inc. All rights reserved.
+ * Author: Jason Wang <jasowang@xxxxxxxxxx>
+ *
+ * Sample driver that creates mdev device that simulates ethernet
+ * device virtio mdev transport.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/uuid.h>
+#include <linux/iommu.h>
+#include <linux/sysfs.h>
+#include <linux/file.h>
+#include <linux/etherdevice.h>
+#include <linux/mdev.h>
+#include <uapi/linux/virtio_mdev.h>
+
+#define VERSION_STRING "0.1"
+#define DRIVER_AUTHOR "NVIDIA Corporation"
+
+#define MVNET_CLASS_NAME "mvnet"
+
+#define MVNET_NAME "mvnet"
+
+/*
+ * Global Structures
+ */
+
+static struct mvnet_dev {
+ struct class *vd_class;
+ struct idr vd_idr;
+ struct device dev;
+} mvnet_dev;
+
+struct mvnet_virtqueue {
+ struct vringh vring;
+ struct vringh_kiov iov;
+ unsigned short head;
+ bool ready;
+ u32 desc_addr_lo;
+ u32 desc_addr_hi;
+ u32 device_addr_lo;
+ u32 device_addr_hi;
+ u32 driver_addr_lo;
+ u32 driver_addr_hi;
+ u64 desc_addr;
+ u64 device_addr;
+ u64 driver_addr;
+ void *private;
+ irqreturn_t (*cb)(void *);
+};
+
+#define MVNET_QUEUE_ALIGN PAGE_SIZE
+#define MVNET_QUEUE_MAX 256
+#define MVNET_MAGIC_VALUE ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)
+#define MVNET_VERSION 0x1 /* Implies virtio 1.0 */
+#define MVNET_DEVICE_ID 0x1 /* network card */
+#define MVNET_VENDOR_ID 0 /* is this correct ? */
+#define MVNET_DEVICE_FEATURES VIRTIO_F_VERSION_1
+
+u64 mvnet_features = (1ULL << VIRTIO_F_ANY_LAYOUT) |
+ (1ULL << VIRTIO_F_VERSION_1) |
+ (1ULL << VIRTIO_F_IOMMU_PLATFORM) ;
+
+/* State of each mdev device */
+struct mvnet_state {
+ struct mvnet_virtqueue vqs[2];
+ struct work_struct work;
+ spinlock_t lock;
+ struct mdev_device *mdev;
+ struct virtio_net_config config;
+ struct virtio_mdev_callback *cbs;
+ void *buffer;
+ u32 queue_sel;
+ u32 driver_features_sel;
+ u32 driver_features[2];
+ u32 device_features_sel;
+ u32 status;
+ u32 generation;
+ u32 num;
+ struct list_head next;
+};
+
+static struct mutex mdev_list_lock;
+static struct list_head mdev_devices_list;
+
+static void mvnet_queue_ready(struct mvnet_state *mvnet, unsigned idx)
+{
+ struct mvnet_virtqueue *vq = &mvnet->vqs[idx];
+ int ret;
+
+ vq->desc_addr = (u64)vq->desc_addr_hi << 32 | vq->desc_addr_lo;
+ vq->device_addr = (u64)vq->device_addr_hi << 32 | vq->device_addr_lo;
+ vq->driver_addr = (u64)vq->driver_addr_hi << 32 | vq->driver_addr_lo;
+
+ ret = vringh_init_kern(&vq->vring, mvnet_features, MVNET_QUEUE_MAX,
+ false, (struct vring_desc *)vq->desc_addr,
+ (struct vring_avail *)vq->driver_addr,
+ (struct vring_used *)vq->device_addr);
+}
+
+static ssize_t mvnet_read_config(struct mdev_device *mdev,
+ u32 *val, loff_t pos)
+{
+ struct mvnet_state *mvnet;
+ struct mvnet_virtqueue *vq;
+ u32 queue_sel;
+
+ if (!mdev || !val)
+ return -EINVAL;
+
+ mvnet = mdev_get_drvdata(mdev);
+ if (!mvnet) {
+ pr_err("%s mvnet not found\n", __func__);
+ return -EINVAL;
+ }
+
+ queue_sel = mvnet->queue_sel;
+ vq = &mvnet->vqs[queue_sel];
+
+ switch (pos) {
+ case VIRTIO_MDEV_MAGIC_VALUE:
+ *val = MVNET_MAGIC_VALUE;
+ break;
+ case VIRTIO_MDEV_VERSION:
+ *val = MVNET_VERSION;
+ break;
+ case VIRTIO_MDEV_DEVICE_ID:
+ *val = MVNET_DEVICE_ID;
+ break;
+ case VIRTIO_MDEV_VENDOR_ID:
+ *val = MVNET_VENDOR_ID;
+ break;
+ case VIRTIO_MDEV_DEVICE_FEATURES:
+ if (mvnet->device_features_sel)
+ *val = mvnet_features >> 32;
+ else
+ *val = mvnet_features;
+ break;
+ case VIRTIO_MDEV_QUEUE_NUM_MAX:
+ *val = MVNET_QUEUE_MAX;
+ break;
+ case VIRTIO_MDEV_QUEUE_READY:
+ *val = vq->ready;
+ break;
+ case VIRTIO_MDEV_QUEUE_ALIGN:
+ *val = MVNET_QUEUE_ALIGN;
+ break;
+ case VIRTIO_MDEV_STATUS:
+ *val = mvnet->status;
+ break;
+ case VIRTIO_MDEV_QUEUE_DESC_LOW:
+ *val = vq->desc_addr_lo;
+ break;
+ case VIRTIO_MDEV_QUEUE_DESC_HIGH:
+ *val = vq->desc_addr_hi;
+ break;
+ case VIRTIO_MDEV_QUEUE_AVAIL_LOW:
+ *val = vq->driver_addr_lo;
+ break;
+ case VIRTIO_MDEV_QUEUE_AVAIL_HIGH:
+ *val = vq->driver_addr_hi;
+ break;
+ case VIRTIO_MDEV_QUEUE_USED_LOW:
+ *val = vq->device_addr_lo;
+ break;
+ case VIRTIO_MDEV_QUEUE_USED_HIGH:
+ *val = vq->device_addr_hi;
+ break;
+ case VIRTIO_MDEV_CONFIG_GENERATION:
+ *val = 1;
+ break;
+ default:
+ pr_err("Unsupported mdev read offset at 0x%x\n", pos);
+ break;
+ }
+
+ return 4;
+}
+
+static ssize_t mvnet_read_net_config(struct mdev_device *mdev,
+ char *buf, size_t count, loff_t pos)
+{
+ struct mvnet_state *mvnet = mdev_get_drvdata(mdev);
+
+ if (!mvnet) {
+ pr_err("%s mvnet not found\n", __func__);
+ return -EINVAL;
+ }
+
+ if (pos + count > sizeof(mvnet->config))
+ return -EINVAL;
+
+ memcpy(buf, &mvnet->config + (unsigned)pos, count);
+
+ return count;
+}
+
+static void mvnet_vq_reset(struct mvnet_virtqueue *vq)
+{
+ vq->ready = 0;
+ vq->desc_addr_lo = vq->desc_addr_hi = 0;
+ vq->device_addr_lo = vq->device_addr_hi = 0;
+ vq->driver_addr_lo = vq->driver_addr_hi = 0;
+ vq->desc_addr = 0;
+ vq->driver_addr = 0;
+ vq->device_addr = 0;
+ vringh_init_kern(&vq->vring, mvnet_features, MVNET_QUEUE_MAX,
+ false, 0, 0, 0);
+}
+
+static void mvnet_reset(struct mvnet_state *mvnet)
+{
+ int i;
+
+ for (i = 0; i < 2; i++)
+ mvnet_vq_reset(&mvnet->vqs[i]);
+
+ mvnet->queue_sel = 0;
+ mvnet->driver_features_sel = 0;
+ mvnet->device_features_sel = 0;
+ mvnet->status = 0;
+ ++mvnet->generation;
+}
+
+static ssize_t mvnet_write_config(struct mdev_device *mdev,
+ u32 *val, loff_t pos)
+{
+ struct mvnet_state *mvnet;
+ struct mvnet_virtqueue *vq;
+ u32 queue_sel;
+
+ if (!mdev || !val)
+ return -EINVAL;
+
+ mvnet = mdev_get_drvdata(mdev);
+ if (!mvnet) {
+ pr_err("%s mvnet not found\n", __func__);
+ return -EINVAL;
+ }
+
+ queue_sel = mvnet->queue_sel;
+ vq = &mvnet->vqs[queue_sel];
+
+ switch (pos) {
+ case VIRTIO_MDEV_DEVICE_FEATURES_SEL:
+ mvnet->device_features_sel = *val;
+ break;
+ case VIRTIO_MDEV_DRIVER_FEATURES:
+ mvnet->driver_features[mvnet->driver_features_sel] = *val;
+ break;
+ case VIRTIO_MDEV_DRIVER_FEATURES_SEL:
+ mvnet->driver_features_sel = *val;
+ break;
+ case VIRTIO_MDEV_QUEUE_SEL:
+ mvnet->queue_sel = *val;
+ break;
+ case VIRTIO_MDEV_QUEUE_NUM:
+ mvnet->num = *val;
+ break;
+ case VIRTIO_MDEV_QUEUE_READY:
+ vq->ready = *val;
+ if (vq->ready) {
+ spin_lock(&mvnet->lock);
+ mvnet_queue_ready(mvnet, queue_sel);
+ spin_unlock(&mvnet->lock);
+ }
+ break;
+ case VIRTIO_MDEV_QUEUE_NOTIFY:
+ if (vq->ready)
+ schedule_work(&mvnet->work);
+ break;
+ case VIRTIO_MDEV_STATUS:
+ mvnet->status = *val;
+ if (*val == 0) {
+ spin_lock(&mvnet->lock);
+ mvnet_reset(mvnet);
+ spin_unlock(&mvnet->lock);
+ }
+ break;
+ case VIRTIO_MDEV_QUEUE_DESC_LOW:
+ vq->desc_addr_lo = *val;
+ break;
+ case VIRTIO_MDEV_QUEUE_DESC_HIGH:
+ vq->desc_addr_hi = *val;
+ break;
+ case VIRTIO_MDEV_QUEUE_AVAIL_LOW:
+ vq->driver_addr_lo = *val;
+ break;
+ case VIRTIO_MDEV_QUEUE_AVAIL_HIGH:
+ vq->driver_addr_hi = *val;
+ break;
+ case VIRTIO_MDEV_QUEUE_USED_LOW:
+ vq->device_addr_lo = *val;
+ break;
+ case VIRTIO_MDEV_QUEUE_USED_HIGH:
+ vq->device_addr_hi = *val;
+ break;
+ default:
+ pr_err("Unsupported write offset! 0x%x\n", pos);
+ break;
+ }
+ spin_unlock(&mvnet->lock);
+
+ return 4;
+}
+
+static void mvnet_work(struct work_struct *work)
+{
+ struct mvnet_state *mvnet = container_of(work, struct
+ mvnet_state, work);
+ struct mvnet_virtqueue *txq = &mvnet->vqs[1];
+ struct mvnet_virtqueue *rxq = &mvnet->vqs[0];
+ size_t read, write, total_write;
+ unsigned long flags;
+ int err;
+ int pkts = 0;
+
+ spin_lock(&mvnet->lock);
+
+ if (!txq->ready || !rxq->ready)
+ goto out;
+
+ while (true) {
+ total_write = 0;
+ err = vringh_getdesc_kern(&txq->vring, &txq->iov, NULL,
+ &txq->head, GFP_KERNEL);
+ if (err <= 0)
+ break;
+
+ err = vringh_getdesc_kern(&rxq->vring, NULL, &rxq->iov,
+ &rxq->head, GFP_KERNEL);
+ if (err <= 0) {
+ vringh_complete_kern(&txq->vring, txq->head, 0);
+ break;
+ }
+
+ while (true) {
+ read = vringh_iov_pull_kern(&txq->iov, mvnet->buffer,
+ PAGE_SIZE);
+ if (read <= 0)
+ break;
+
+ write = vringh_iov_push_kern(&rxq->iov, mvnet->buffer,
+ read);
+ if (write <= 0)
+ break;
+
+ total_write += write;
+ }
+
+ /* Make sure data is wrote before advancing index */
+ smp_wmb();
+
+ vringh_complete_kern(&txq->vring, txq->head, 0);
+ vringh_complete_kern(&rxq->vring, rxq->head, total_write);
+
+ /* Make sure used is visible before rasing the
+ interrupt */
+ smp_wmb();
+
+ local_bh_disable();
+ if (txq->cb)
+ txq->cb(txq->private);
+ if (rxq->cb)
+ rxq->cb(rxq->private);
+ local_bh_enable();
+
+ pkts ++;
+ if (pkts > 4) {
+ schedule_work(&mvnet->work);
+ goto out;
+ }
+ }
+
+out:
+ spin_unlock(&mvnet->lock);
+}
+
+static dma_addr_t mvnet_map_page(struct device *dev, struct page *page,
+ unsigned long offset, size_t size,
+ enum dma_data_direction dir,
+ unsigned long attrs)
+{
+ /* Vringh can only use VA */
+ return page_address(page) + offset;
+}
+
+static void mvnet_unmap_page(struct device *dev, dma_addr_t dma_addr,
+ size_t size, enum dma_data_direction dir,
+ unsigned long attrs)
+{
+ return ;
+}
+
+static void *mvnet_alloc_coherent(struct device *dev, size_t size,
+ dma_addr_t *dma_addr, gfp_t flag,
+ unsigned long attrs)
+{
+ void *ret = kmalloc(size, flag);
+
+ if (ret == NULL)
+ *dma_addr = DMA_MAPPING_ERROR;
+ else
+ *dma_addr = ret;
+
+ return ret;
+}
+
+static void mvnet_free_coherent(struct device *dev, size_t size,
+ void *vaddr, dma_addr_t dma_addr,
+ unsigned long attrs)
+{
+ kfree(dma_addr);
+}
+
+static const struct dma_map_ops mvnet_dma_ops = {
+ .map_page = mvnet_map_page,
+ .unmap_page = mvnet_unmap_page,
+ .alloc = mvnet_alloc_coherent,
+ .free = mvnet_free_coherent,
+};
+
+static int mvnet_create(struct kobject *kobj, struct mdev_device *mdev)
+{
+ struct mvnet_state *mvnet;
+ struct virtio_net_config *config;
+
+ if (!mdev)
+ return -EINVAL;
+
+ mvnet = kzalloc(sizeof(struct mvnet_state), GFP_KERNEL);
+ if (mvnet == NULL)
+ return -ENOMEM;
+
+ mvnet->buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!mvnet->buffer) {
+ kfree(mvnet);
+ return -ENOMEM;
+ }
+
+ config = &mvnet->config;
+ config->mtu = 1500;
+ config->status = VIRTIO_NET_S_LINK_UP;
+ eth_random_addr(config->mac);
+
+ INIT_WORK(&mvnet->work, mvnet_work);
+
+ spin_lock_init(&mvnet->lock);
+ mvnet->mdev = mdev;
+ mdev_set_drvdata(mdev, mvnet);
+
+ mutex_lock(&mdev_list_lock);
+ list_add(&mvnet->next, &mdev_devices_list);
+ mutex_unlock(&mdev_list_lock);
+
+ mdev_set_dma_ops(mdev, &mvnet_dma_ops);
+
+ return 0;
+}
+
+static int mvnet_remove(struct mdev_device *mdev)
+{
+ struct mvnet_state *mds, *tmp_mds;
+ struct mvnet_state *mvnet = mdev_get_drvdata(mdev);
+ int ret = -EINVAL;
+
+ mutex_lock(&mdev_list_lock);
+ list_for_each_entry_safe(mds, tmp_mds, &mdev_devices_list, next) {
+ if (mvnet == mds) {
+ list_del(&mvnet->next);
+ mdev_set_drvdata(mdev, NULL);
+ kfree(mvnet->buffer);
+ kfree(mvnet);
+ ret = 0;
+ break;
+ }
+ }
+ mutex_unlock(&mdev_list_lock);
+
+ return ret;
+}
+
+static ssize_t mvnet_read(struct mdev_device *mdev, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ ssize_t ret;
+
+ if (*ppos < VIRTIO_MDEV_CONFIG) {
+ if (count == 4)
+ ret = mvnet_read_config(mdev, (u32 *)buf, *ppos);
+ else
+ ret = -EINVAL;
+ *ppos += 4;
+ } else if (*ppos < VIRTIO_MDEV_CONFIG + sizeof(struct virtio_net_config)) {
+ ret = mvnet_read_net_config(mdev, buf, count,
+ *ppos - VIRTIO_MDEV_CONFIG);
+ *ppos += count;
+ } else {
+ ret = -EINVAL;
+ }
+
+ return ret;
+}
+
+static ssize_t mvnet_write(struct mdev_device *mdev, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ int ret;
+
+ if (*ppos < VIRTIO_MDEV_CONFIG) {
+ if (count == 4)
+ ret = mvnet_write_config(mdev, (u32 *)buf, *ppos);
+ else
+ ret = -EINVAL;
+ *ppos += 4;
+ } else {
+ /* No writable net config */
+ ret = -EINVAL;
+ }
+
+ return ret;
+}
+
+static long mvnet_ioctl(struct mdev_device *mdev, unsigned int cmd,
+ unsigned long arg)
+{
+ int ret = 0;
+ struct mvnet_state *mvnet;
+ struct virtio_mdev_callback *cb;
+
+ if (!mdev)
+ return -EINVAL;
+
+ mvnet = mdev_get_drvdata(mdev);
+ if (!mvnet)
+ return -ENODEV;
+
+ spin_lock(&mvnet->lock);
+
+ switch (cmd) {
+ case VIRTIO_MDEV_SET_VQ_CALLBACK:
+ cb = (struct virtio_mdev_callback *)arg;
+ mvnet->vqs[mvnet->queue_sel].cb = cb->callback;
+ mvnet->vqs[mvnet->queue_sel].private = cb->private;
+ break;
+ case VIRTIO_MDEV_SET_CONFIG_CALLBACK:
+ break;
+ default:
+ pr_err("Not supportted ioctl cmd 0x%x\n", cmd);
+ ret = -ENOTTY;
+ break;
+ }
+
+ spin_unlock(&mvnet->lock);
+
+ return ret;
+}
+
+static int mvnet_open(struct mdev_device *mdev)
+{
+ pr_info("%s\n", __func__);
+ return 0;
+}
+
+static void mvnet_close(struct mdev_device *mdev)
+{
+ pr_info("%s\n", __func__);
+}
+
+static ssize_t
+sample_mvnet_dev_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "This is phy device\n");
+}
+
+static DEVICE_ATTR_RO(sample_mvnet_dev);
+
+static struct attribute *mvnet_dev_attrs[] = {
+ &dev_attr_sample_mvnet_dev.attr,
+ NULL,
+};
+
+static const struct attribute_group mvnet_dev_group = {
+ .name = "mvnet_dev",
+ .attrs = mvnet_dev_attrs,
+};
+
+static const struct attribute_group *mvnet_dev_groups[] = {
+ &mvnet_dev_group,
+ NULL,
+};
+
+static ssize_t
+sample_mdev_dev_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ if (mdev_from_dev(dev))
+ return sprintf(buf, "This is MDEV %s\n", dev_name(dev));
+
+ return sprintf(buf, "\n");
+}
+
+static DEVICE_ATTR_RO(sample_mdev_dev);
+
+static struct attribute *mdev_dev_attrs[] = {
+ &dev_attr_sample_mdev_dev.attr,
+ NULL,
+};
+
+static const struct attribute_group mdev_dev_group = {
+ .name = "vendor",
+ .attrs = mdev_dev_attrs,
+};
+
+static const struct attribute_group *mdev_dev_groups[] = {
+ &mdev_dev_group,
+ NULL,
+};
+
+#define MVNET_STRING_LEN 16
+
+static ssize_t
+name_show(struct kobject *kobj, struct device *dev, char *buf)
+{
+ char name[MVNET_STRING_LEN];
+ const char *name_str = "virtio-net";
+
+ snprintf(name, MVNET_STRING_LEN, "%s", dev_driver_string(dev));
+ if (!strcmp(kobj->name, name))
+ return sprintf(buf, "%s\n", name_str);
+
+ return -EINVAL;
+}
+
+static MDEV_TYPE_ATTR_RO(name);
+
+static ssize_t
+available_instances_show(struct kobject *kobj, struct device *dev, char *buf)
+{
+ return sprintf(buf, "%d\n", INT_MAX);
+}
+
+static 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", VIRTIO_MDEV_DEVICE_API_STRING);
+}
+
+static MDEV_TYPE_ATTR_RO(device_api);
+
+static struct attribute *mdev_types_attrs[] = {
+ &mdev_type_attr_name.attr,
+ &mdev_type_attr_device_api.attr,
+ &mdev_type_attr_available_instances.attr,
+ NULL,
+};
+
+static struct attribute_group mdev_type_group = {
+ .name = "",
+ .attrs = mdev_types_attrs,
+};
+
+static struct attribute_group *mdev_type_groups[] = {
+ &mdev_type_group,
+ NULL,
+};
+
+static const struct mdev_parent_ops mdev_fops = {
+ .owner = THIS_MODULE,
+ .dev_attr_groups = mvnet_dev_groups,
+ .mdev_attr_groups = mdev_dev_groups,
+ .supported_type_groups = mdev_type_groups,
+ .create = mvnet_create,
+ .remove = mvnet_remove,
+ .open = mvnet_open,
+ .release = mvnet_close,
+ .read = mvnet_read,
+ .write = mvnet_write,
+ .ioctl = mvnet_ioctl,
+};
+
+static void mvnet_device_release(struct device *dev)
+{
+ dev_dbg(dev, "mvnet: released\n");
+}
+
+static int __init mvnet_dev_init(void)
+{
+ int ret = 0;
+
+ pr_info("mvnet_dev: %s\n", __func__);
+
+ memset(&mvnet_dev, 0, sizeof(mvnet_dev));
+
+ idr_init(&mvnet_dev.vd_idr);
+
+ mvnet_dev.vd_class = class_create(THIS_MODULE, MVNET_CLASS_NAME);
+
+ if (IS_ERR(mvnet_dev.vd_class)) {
+ pr_err("Error: failed to register mvnet_dev class\n");
+ ret = PTR_ERR(mvnet_dev.vd_class);
+ goto failed1;
+ }
+
+ mvnet_dev.dev.class = mvnet_dev.vd_class;
+ mvnet_dev.dev.release = mvnet_device_release;
+ dev_set_name(&mvnet_dev.dev, "%s", MVNET_NAME);
+
+ ret = device_register(&mvnet_dev.dev);
+ if (ret)
+ goto failed2;
+
+ ret = mdev_register_device(&mvnet_dev.dev, &mdev_fops);
+ if (ret)
+ goto failed3;
+
+ mutex_init(&mdev_list_lock);
+ INIT_LIST_HEAD(&mdev_devices_list);
+
+ goto all_done;
+
+failed3:
+
+ device_unregister(&mvnet_dev.dev);
+failed2:
+ class_destroy(mvnet_dev.vd_class);
+
+failed1:
+all_done:
+ return ret;
+}
+
+static void __exit mvnet_dev_exit(void)
+{
+ mvnet_dev.dev.bus = NULL;
+ mdev_unregister_device(&mvnet_dev.dev);
+
+ device_unregister(&mvnet_dev.dev);
+ idr_destroy(&mvnet_dev.vd_idr);
+ class_destroy(mvnet_dev.vd_class);
+ mvnet_dev.vd_class = NULL;
+ pr_info("mvnet_dev: Unloaded!\n");
+}
+
+module_init(mvnet_dev_init)
+module_exit(mvnet_dev_exit)
+
+MODULE_LICENSE("GPL v2");
+MODULE_INFO(supported, "Test driver that simulate serial port over PCI");
+MODULE_VERSION(VERSION_STRING);
+MODULE_AUTHOR(DRIVER_AUTHOR);
--
2.19.1