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>

1 files changed, 25 insertions, 0 deletions

diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
new file mode 100644
index 0000000000..82fc536831
--- /dev/null
+++ b/drivers/virtio/Kconfig
@@ -0,0 +1,25 @@
+# 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.
+
+menu "VirtIO Drivers"
+
+config VIRTIO
+	bool
+	help
+	  This option is selected by any driver which implements the virtio
+	  transport, such as CONFIG_VIRTIO_MMIO or CONFIG_VIRTIO_PCI.
+
+endmenu