virtio: Add a Sandbox transport driver

This driver provides support for Sandbox implementation of virtio
transport driver which is used for testing purpose only.

Two drivers are provided. The 2nd one is a driver that lacks the
'notify' op.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

drivers/virtio/Kconfig

@@ -37,6 +37,14 @@ config VIRTIO_PCI
 	  This driver provides support for virtio based paravirtual device
 	  drivers over PCI.
 
+config VIRTIO_SANDBOX
+	bool "Sandbox driver for virtio devices"
+	depends on SANDBOX
+	select VIRTIO
+	help
+	  This driver provides support for Sandbox implementation of virtio
+	  transport driver which is used for testing purpose only.
+
 config VIRTIO_NET
 	bool "virtio net driver"
 	depends on VIRTIO

drivers/virtio/Makefile

@@ -6,5 +6,6 @@
 obj-y += virtio-uclass.o virtio_ring.o
 obj-$(CONFIG_VIRTIO_MMIO) += virtio_mmio.o
 obj-$(CONFIG_VIRTIO_PCI) += virtio_pci_legacy.o virtio_pci_modern.o
+obj-$(CONFIG_VIRTIO_SANDBOX) += virtio_sandbox.o
 obj-$(CONFIG_VIRTIO_NET) += virtio_net.o
 obj-$(CONFIG_VIRTIO_BLK) += virtio_blk.o

drivers/virtio/virtio_sandbox.c

@@ -0,0 +1,233 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * VirtIO Sandbox transport driver, for testing purpose only
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <virtio_types.h>
+#include <virtio.h>
+#include <virtio_ring.h>
+#include <linux/compat.h>
+#include <linux/io.h>
+
+struct virtio_sandbox_priv {
+	u8 id;
+	u8 status;
+	u64 device_features;
+	u64 driver_features;
+	ulong queue_desc;
+	ulong queue_available;
+	ulong queue_used;
+};
+
+static int virtio_sandbox_get_config(struct udevice *udev, unsigned int offset,
+				     void *buf, unsigned int len)
+{
+	return 0;
+}
+
+static int virtio_sandbox_set_config(struct udevice *udev, unsigned int offset,
+				     const void *buf, unsigned int len)
+{
+	return 0;
+}
+
+static int virtio_sandbox_get_status(struct udevice *udev, u8 *status)
+{
+	struct virtio_sandbox_priv *priv = dev_get_priv(udev);
+
+	*status = priv->status;
+
+	return 0;
+}
+
+static int virtio_sandbox_set_status(struct udevice *udev, u8 status)
+{
+	struct virtio_sandbox_priv *priv = dev_get_priv(udev);
+
+	/* We should never be setting status to 0 */
+	WARN_ON(status == 0);
+
+	priv->status = status;
+
+	return 0;
+}
+
+static int virtio_sandbox_reset(struct udevice *udev)
+{
+	struct virtio_sandbox_priv *priv = dev_get_priv(udev);
+
+	/* 0 status means a reset */
+	priv->status = 0;
+
+	return 0;
+}
+
+static int virtio_sandbox_get_features(struct udevice *udev, u64 *features)
+{
+	struct virtio_sandbox_priv *priv = dev_get_priv(udev);
+
+	*features = priv->device_features;
+
+	return 0;
+}
+
+static int virtio_sandbox_set_features(struct udevice *udev)
+{
+	struct virtio_sandbox_priv *priv = dev_get_priv(udev);
+	struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(udev);
+
+	priv->driver_features = uc_priv->features;
+
+	return 0;
+}
+
+static struct virtqueue *virtio_sandbox_setup_vq(struct udevice *udev,
+						 unsigned int index)
+{
+	struct virtio_sandbox_priv *priv = dev_get_priv(udev);
+	struct virtqueue *vq;
+	ulong addr;
+	int err;
+
+	/* Create the vring */
+	vq = vring_create_virtqueue(index, 4, 4096, udev);
+	if (!vq) {
+		err = -ENOMEM;
+		goto error_new_virtqueue;
+	}
+
+	addr = virtqueue_get_desc_addr(vq);
+	priv->queue_desc = addr;
+
+	addr = virtqueue_get_avail_addr(vq);
+	priv->queue_available = addr;
+
+	addr = virtqueue_get_used_addr(vq);
+	priv->queue_used = addr;
+
+	return vq;
+
+error_new_virtqueue:
+	return ERR_PTR(err);
+}
+
+static void virtio_sandbox_del_vq(struct virtqueue *vq)
+{
+	vring_del_virtqueue(vq);
+}
+
+static int virtio_sandbox_del_vqs(struct udevice *udev)
+{
+	struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(udev);
+	struct virtqueue *vq, *n;
+
+	list_for_each_entry_safe(vq, n, &uc_priv->vqs, list)
+		virtio_sandbox_del_vq(vq);
+
+	return 0;
+}
+
+static int virtio_sandbox_find_vqs(struct udevice *udev, unsigned int nvqs,
+				   struct virtqueue *vqs[])
+{
+	int i;
+
+	for (i = 0; i < nvqs; ++i) {
+		vqs[i] = virtio_sandbox_setup_vq(udev, i);
+		if (IS_ERR(vqs[i])) {
+			virtio_sandbox_del_vqs(udev);
+			return PTR_ERR(vqs[i]);
+		}
+	}
+
+	return 0;
+}
+
+static int virtio_sandbox_notify(struct udevice *udev, struct virtqueue *vq)
+{
+	return 0;
+}
+
+static int virtio_sandbox_probe(struct udevice *udev)
+{
+	struct virtio_sandbox_priv *priv = dev_get_priv(udev);
+	struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(udev);
+
+	/* fake some information for testing */
+	priv->device_features = VIRTIO_F_VERSION_1;
+	uc_priv->device = VIRTIO_ID_BLOCK;
+	uc_priv->vendor = ('u' << 24) | ('b' << 16) | ('o' << 8) | 't';
+
+	return 0;
+}
+
+/* check virtio device driver's remove routine was called to reset the device */
+static int virtio_sandbox_child_post_remove(struct udevice *vdev)
+{
+	u8 status;
+
+	virtio_get_status(vdev, &status);
+	if (status)
+		panic("virtio device was not reset\n");
+
+	return 0;
+}
+
+static const struct dm_virtio_ops virtio_sandbox1_ops = {
+	.get_config	= virtio_sandbox_get_config,
+	.set_config	= virtio_sandbox_set_config,
+	.get_status	= virtio_sandbox_get_status,
+	.set_status	= virtio_sandbox_set_status,
+	.reset		= virtio_sandbox_reset,
+	.get_features	= virtio_sandbox_get_features,
+	.set_features	= virtio_sandbox_set_features,
+	.find_vqs	= virtio_sandbox_find_vqs,
+	.del_vqs	= virtio_sandbox_del_vqs,
+	.notify		= virtio_sandbox_notify,
+};
+
+static const struct udevice_id virtio_sandbox1_ids[] = {
+	{ .compatible = "sandbox,virtio1" },
+	{ }
+};
+
+U_BOOT_DRIVER(virtio_sandbox1) = {
+	.name	= "virtio-sandbox1",
+	.id	= UCLASS_VIRTIO,
+	.of_match = virtio_sandbox1_ids,
+	.ops	= &virtio_sandbox1_ops,
+	.probe	= virtio_sandbox_probe,
+	.child_post_remove = virtio_sandbox_child_post_remove,
+	.priv_auto_alloc_size = sizeof(struct virtio_sandbox_priv),
+};
+
+/* this one without notify op */
+static const struct dm_virtio_ops virtio_sandbox2_ops = {
+	.get_config	= virtio_sandbox_get_config,
+	.set_config	= virtio_sandbox_set_config,
+	.get_status	= virtio_sandbox_get_status,
+	.set_status	= virtio_sandbox_set_status,
+	.reset		= virtio_sandbox_reset,
+	.get_features	= virtio_sandbox_get_features,
+	.set_features	= virtio_sandbox_set_features,
+	.find_vqs	= virtio_sandbox_find_vqs,
+	.del_vqs	= virtio_sandbox_del_vqs,
+};
+
+static const struct udevice_id virtio_sandbox2_ids[] = {
+	{ .compatible = "sandbox,virtio2" },
+	{ }
+};
+
+U_BOOT_DRIVER(virtio_sandbox2) = {
+	.name	= "virtio-sandbox2",
+	.id	= UCLASS_VIRTIO,
+	.of_match = virtio_sandbox2_ids,
+	.ops	= &virtio_sandbox2_ops,
+	.probe	= virtio_sandbox_probe,
+	.priv_auto_alloc_size = sizeof(struct virtio_sandbox_priv),
+};