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 <[email protected]>
Signed-off-by: Bin Meng <[email protected]>
Reviewed-by: Simon Glass <[email protected]>