dm: Add a new uclass driver for VirtIO transport devices
This adds a new virtio uclass driver for “virtio” [1] family of
devices that are are found in virtual environments like QEMU,
yet by design they look like physical devices to the guest.
The uclass driver provides child_pre_probe() and child_post_probe()
methods to do some common operations for virtio device drivers like
device and driver supported feature negotiation, etc.
[1] http://docs.oasis-open.org/virtio/virtio/v1.0/virtio-v1.0.pdf
Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/virtio/virtio-uclass.c b/drivers/virtio/virtio-uclass.c
new file mode 100644
index 0000000..34397d7
--- /dev/null
+++ b/drivers/virtio/virtio-uclass.c
@@ -0,0 +1,369 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018, Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * VirtIO is a virtualization standard for network and disk device drivers
+ * where just the guest's device driver "knows" it is running in a virtual
+ * environment, and cooperates with the hypervisor. This enables guests to
+ * get high performance network and disk operations, and gives most of the
+ * performance benefits of paravirtualization. In the U-Boot case, the guest
+ * is U-Boot itself, while the virtual environment are normally QEMU targets
+ * like ARM, RISC-V and x86.
+ *
+ * See http://docs.oasis-open.org/virtio/virtio/v1.0/virtio-v1.0.pdf for
+ * the VirtIO specification v1.0.
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <virtio_types.h>
+#include <virtio.h>
+#include <dm/lists.h>
+
+static const char *const virtio_drv_name[VIRTIO_ID_MAX_NUM] = {
+ [VIRTIO_ID_NET] = VIRTIO_NET_DRV_NAME,
+ [VIRTIO_ID_BLOCK] = VIRTIO_BLK_DRV_NAME,
+};
+
+int virtio_get_config(struct udevice *vdev, unsigned int offset,
+ void *buf, unsigned int len)
+{
+ struct dm_virtio_ops *ops;
+
+ ops = virtio_get_ops(vdev->parent);
+
+ return ops->get_config(vdev->parent, offset, buf, len);
+}
+
+int virtio_set_config(struct udevice *vdev, unsigned int offset,
+ void *buf, unsigned int len)
+{
+ struct dm_virtio_ops *ops;
+
+ ops = virtio_get_ops(vdev->parent);
+
+ return ops->set_config(vdev->parent, offset, buf, len);
+}
+
+int virtio_generation(struct udevice *vdev, u32 *counter)
+{
+ struct dm_virtio_ops *ops;
+
+ ops = virtio_get_ops(vdev->parent);
+ if (!ops->generation)
+ return -ENOSYS;
+
+ return ops->generation(vdev->parent, counter);
+}
+
+int virtio_get_status(struct udevice *vdev, u8 *status)
+{
+ struct dm_virtio_ops *ops;
+
+ ops = virtio_get_ops(vdev->parent);
+
+ return ops->get_status(vdev->parent, status);
+}
+
+int virtio_set_status(struct udevice *vdev, u8 status)
+{
+ struct dm_virtio_ops *ops;
+
+ ops = virtio_get_ops(vdev->parent);
+
+ return ops->set_status(vdev->parent, status);
+}
+
+int virtio_reset(struct udevice *vdev)
+{
+ struct dm_virtio_ops *ops;
+
+ ops = virtio_get_ops(vdev->parent);
+
+ return ops->reset(vdev->parent);
+}
+
+int virtio_get_features(struct udevice *vdev, u64 *features)
+{
+ struct dm_virtio_ops *ops;
+
+ ops = virtio_get_ops(vdev->parent);
+
+ return ops->get_features(vdev->parent, features);
+}
+
+int virtio_set_features(struct udevice *vdev)
+{
+ struct dm_virtio_ops *ops;
+
+ ops = virtio_get_ops(vdev->parent);
+
+ return ops->set_features(vdev->parent);
+}
+
+int virtio_find_vqs(struct udevice *vdev, unsigned int nvqs,
+ struct virtqueue *vqs[])
+{
+ struct dm_virtio_ops *ops;
+
+ ops = virtio_get_ops(vdev->parent);
+
+ return ops->find_vqs(vdev->parent, nvqs, vqs);
+}
+
+int virtio_del_vqs(struct udevice *vdev)
+{
+ struct dm_virtio_ops *ops;
+
+ ops = virtio_get_ops(vdev->parent);
+
+ return ops->del_vqs(vdev->parent);
+}
+
+int virtio_notify(struct udevice *vdev, struct virtqueue *vq)
+{
+ struct dm_virtio_ops *ops;
+
+ ops = virtio_get_ops(vdev->parent);
+
+ return ops->notify(vdev->parent, vq);
+}
+
+void virtio_add_status(struct udevice *vdev, u8 status)
+{
+ u8 old;
+
+ if (!virtio_get_status(vdev, &old))
+ virtio_set_status(vdev, old | status);
+}
+
+int virtio_finalize_features(struct udevice *vdev)
+{
+ struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(vdev->parent);
+ u8 status;
+ int ret;
+
+ ret = virtio_set_features(vdev);
+ if (ret)
+ return ret;
+
+ if (uc_priv->legacy)
+ return 0;
+
+ virtio_add_status(vdev, VIRTIO_CONFIG_S_FEATURES_OK);
+ ret = virtio_get_status(vdev, &status);
+ if (ret)
+ return ret;
+ if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
+ debug("(%s): device refuses features %x\n", vdev->name, status);
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
+void virtio_driver_features_init(struct virtio_dev_priv *priv,
+ const u32 *feature,
+ u32 feature_size,
+ const u32 *feature_legacy,
+ u32 feature_legacy_size)
+{
+ priv->feature_table = feature;
+ priv->feature_table_size = feature_size;
+ priv->feature_table_legacy = feature_legacy;
+ priv->feature_table_size_legacy = feature_legacy_size;
+}
+
+int virtio_init(void)
+{
+ struct udevice *bus;
+ int ret;
+
+ /* Enumerate all known virtio devices */
+ ret = uclass_first_device(UCLASS_VIRTIO, &bus);
+ if (ret)
+ return ret;
+
+ while (bus) {
+ ret = uclass_next_device(&bus);
+ if (ret)
+ break;
+ }
+
+ return ret;
+}
+
+static int virtio_uclass_pre_probe(struct udevice *udev)
+{
+ struct dm_virtio_ops *ops;
+
+ ops = (struct dm_virtio_ops *)(udev->driver->ops);
+
+ /*
+ * Check virtio transport driver ops here so that we don't need
+ * check these ops each time when the virtio_xxx APIs are called.
+ *
+ * Only generation op is optional. All other ops are must-have.
+ */
+ if (!ops->get_config || !ops->set_config ||
+ !ops->get_status || !ops->set_status ||
+ !ops->get_features || !ops->set_features ||
+ !ops->find_vqs || !ops->del_vqs ||
+ !ops->reset || !ops->notify)
+ return -ENOENT;
+
+ return 0;
+}
+
+static int virtio_uclass_post_probe(struct udevice *udev)
+{
+ struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(udev);
+ char dev_name[30], *str;
+ struct udevice *vdev;
+ int ret;
+
+ if (uc_priv->device > VIRTIO_ID_MAX_NUM) {
+ debug("(%s): virtio device ID %d exceeds maximum num\n",
+ udev->name, uc_priv->device);
+ return 0;
+ }
+
+ if (!virtio_drv_name[uc_priv->device]) {
+ debug("(%s): underlying virtio device driver unavailable\n",
+ udev->name);
+ return 0;
+ }
+
+ snprintf(dev_name, sizeof(dev_name), "%s#%d",
+ virtio_drv_name[uc_priv->device], udev->seq);
+ str = strdup(dev_name);
+ if (!str)
+ return -ENOMEM;
+
+ ret = device_bind_driver(udev, virtio_drv_name[uc_priv->device],
+ str, &vdev);
+ if (ret == -ENOENT) {
+ debug("(%s): no driver configured\n", udev->name);
+ return 0;
+ }
+ if (ret) {
+ free(str);
+ return ret;
+ }
+ device_set_name_alloced(vdev);
+
+ INIT_LIST_HEAD(&uc_priv->vqs);
+
+ return 0;
+}
+
+static int virtio_uclass_child_post_bind(struct udevice *vdev)
+{
+ /* Acknowledge that we've seen the device */
+ virtio_add_status(vdev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
+
+ return 0;
+}
+
+static int virtio_uclass_child_pre_probe(struct udevice *vdev)
+{
+ struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(vdev->parent);
+ u64 device_features;
+ u64 driver_features;
+ u64 driver_features_legacy;
+ int i;
+ int ret;
+
+ /*
+ * Save the real virtio device (eg: virtio-net, virtio-blk) to
+ * the transport (parent) device's uclass priv for future use.
+ */
+ uc_priv->vdev = vdev;
+
+ /*
+ * We always start by resetting the device, in case a previous driver
+ * messed it up. This also tests that code path a little.
+ */
+ ret = virtio_reset(vdev);
+ if (ret)
+ goto err;
+
+ /* We have a driver! */
+ virtio_add_status(vdev, VIRTIO_CONFIG_S_DRIVER);
+
+ /* Figure out what features the device supports */
+ virtio_get_features(vdev, &device_features);
+ debug("(%s) plain device features supported %016llx\n",
+ vdev->name, device_features);
+ if (!(device_features & (1ULL << VIRTIO_F_VERSION_1)))
+ uc_priv->legacy = true;
+
+ /* Figure out what features the driver supports */
+ driver_features = 0;
+ for (i = 0; i < uc_priv->feature_table_size; i++) {
+ unsigned int f = uc_priv->feature_table[i];
+
+ WARN_ON(f >= 64);
+ driver_features |= (1ULL << f);
+ }
+
+ /* Some drivers have a separate feature table for virtio v1.0 */
+ if (uc_priv->feature_table_legacy) {
+ driver_features_legacy = 0;
+ for (i = 0; i < uc_priv->feature_table_size_legacy; i++) {
+ unsigned int f = uc_priv->feature_table_legacy[i];
+
+ WARN_ON(f >= 64);
+ driver_features_legacy |= (1ULL << f);
+ }
+ } else {
+ driver_features_legacy = driver_features;
+ }
+
+ if (uc_priv->legacy) {
+ debug("(%s): legacy virtio device\n", vdev->name);
+ uc_priv->features = driver_features_legacy & device_features;
+ } else {
+ debug("(%s): v1.0 complaint virtio device\n", vdev->name);
+ uc_priv->features = driver_features & device_features;
+ }
+
+ /* Transport features always preserved to pass to finalize_features */
+ for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
+ if ((device_features & (1ULL << i)) &&
+ (i == VIRTIO_F_VERSION_1))
+ __virtio_set_bit(vdev->parent, i);
+
+ debug("(%s) final negotiated features supported %016llx\n",
+ vdev->name, uc_priv->features);
+ ret = virtio_finalize_features(vdev);
+ if (ret)
+ goto err;
+
+ return 0;
+
+err:
+ virtio_add_status(vdev, VIRTIO_CONFIG_S_FAILED);
+ return ret;
+}
+
+static int virtio_uclass_child_post_probe(struct udevice *vdev)
+{
+ /* Indicates that the driver is set up and ready to drive the device */
+ virtio_add_status(vdev, VIRTIO_CONFIG_S_DRIVER_OK);
+
+ return 0;
+}
+
+UCLASS_DRIVER(virtio) = {
+ .name = "virtio",
+ .id = UCLASS_VIRTIO,
+ .flags = DM_UC_FLAG_SEQ_ALIAS,
+ .pre_probe = virtio_uclass_pre_probe,
+ .post_probe = virtio_uclass_post_probe,
+ .child_post_bind = virtio_uclass_child_post_bind,
+ .child_pre_probe = virtio_uclass_child_pre_probe,
+ .child_post_probe = virtio_uclass_child_post_probe,
+ .per_device_auto_alloc_size = sizeof(struct virtio_dev_priv),
+};