virtio: Add net driver support

This adds virtio net device driver support.

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, 218 insertions, 0 deletions

diff --git a/drivers/virtio/virtio_net.c b/drivers/virtio/virtio_net.c
new file mode 100644
index 0000000000..5bb6a9fcc9
--- /dev/null
+++ b/drivers/virtio/virtio_net.c
@@ -0,0 +1,218 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018, Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <net.h>
+#include <virtio_types.h>
+#include <virtio.h>
+#include <virtio_ring.h>
+#include "virtio_net.h"
+
+/* Amount of buffers to keep in the RX virtqueue */
+#define VIRTIO_NET_NUM_RX_BUFS	32
+
+/*
+ * This value comes from the VirtIO spec: 1500 for maximum packet size,
+ * 14 for the Ethernet header, 12 for virtio_net_hdr. In total 1526 bytes.
+ */
+#define VIRTIO_NET_RX_BUF_SIZE	1526
+
+struct virtio_net_priv {
+	union {
+		struct virtqueue *vqs[2];
+		struct {
+			struct virtqueue *rx_vq;
+			struct virtqueue *tx_vq;
+		};
+	};
+
+	char rx_buff[VIRTIO_NET_NUM_RX_BUFS][VIRTIO_NET_RX_BUF_SIZE];
+	bool rx_running;
+};
+
+/*
+ * For simplicity, the driver only negotiates the VIRTIO_NET_F_MAC feature.
+ * For the VIRTIO_NET_F_STATUS feature, we don't negotiate it, hence per spec
+ * we should assume the link is always active.
+ */
+static const u32 feature[] = {
+	VIRTIO_NET_F_MAC
+};
+
+static const u32 feature_legacy[] = {
+	VIRTIO_NET_F_MAC
+};
+
+static int virtio_net_start(struct udevice *dev)
+{
+	struct virtio_net_priv *priv = dev_get_priv(dev);
+	struct virtio_sg sg;
+	struct virtio_sg *sgs[] = { &sg };
+	int i;
+
+	if (!priv->rx_running) {
+		/* receive buffer length is always 1526 */
+		sg.length = VIRTIO_NET_RX_BUF_SIZE;
+
+		/* setup the receive buffer address */
+		for (i = 0; i < VIRTIO_NET_NUM_RX_BUFS; i++) {
+			sg.addr = priv->rx_buff[i];
+			virtqueue_add(priv->rx_vq, sgs, 0, 1);
+		}
+
+		virtqueue_kick(priv->rx_vq);
+
+		/* setup the receive queue only once */
+		priv->rx_running = true;
+	}
+
+	return 0;
+}
+
+static int virtio_net_send(struct udevice *dev, void *packet, int length)
+{
+	struct virtio_net_priv *priv = dev_get_priv(dev);
+	struct virtio_net_hdr hdr;
+	struct virtio_sg hdr_sg = { &hdr, sizeof(hdr) };
+	struct virtio_sg data_sg = { packet, length };
+	struct virtio_sg *sgs[] = { &hdr_sg, &data_sg };
+	int ret;
+
+	memset(&hdr, 0, sizeof(struct virtio_net_hdr));
+
+	ret = virtqueue_add(priv->tx_vq, sgs, 2, 0);
+	if (ret)
+		return ret;
+
+	virtqueue_kick(priv->tx_vq);
+
+	while (1) {
+		if (virtqueue_get_buf(priv->tx_vq, NULL))
+			break;
+	}
+
+	return 0;
+}
+
+static int virtio_net_recv(struct udevice *dev, int flags, uchar **packetp)
+{
+	struct virtio_net_priv *priv = dev_get_priv(dev);
+	unsigned int len;
+	void *buf;
+
+	buf = virtqueue_get_buf(priv->rx_vq, &len);
+	if (!buf)
+		return -EAGAIN;
+
+	*packetp = buf + sizeof(struct virtio_net_hdr);
+	return len - sizeof(struct virtio_net_hdr);
+}
+
+static int virtio_net_free_pkt(struct udevice *dev, uchar *packet, int length)
+{
+	struct virtio_net_priv *priv = dev_get_priv(dev);
+	void *buf = packet - sizeof(struct virtio_net_hdr);
+	struct virtio_sg sg = { buf, VIRTIO_NET_RX_BUF_SIZE };
+	struct virtio_sg *sgs[] = { &sg };
+
+	/* Put the buffer back to the rx ring */
+	virtqueue_add(priv->rx_vq, sgs, 0, 1);
+
+	return 0;
+}
+
+static void virtio_net_stop(struct udevice *dev)
+{
+	/*
+	 * There is no way to stop the queue from running, unless we issue
+	 * a reset to the virtio device, and re-do the queue initialization
+	 * from the beginning.
+	 */
+}
+
+static int virtio_net_write_hwaddr(struct udevice *dev)
+{
+	struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(dev->parent);
+	struct eth_pdata *pdata = dev_get_platdata(dev);
+	int i;
+
+	/*
+	 * v1.0 compliant device's MAC address is set through control channel,
+	 * which we don't support for now.
+	 */
+	if (!uc_priv->legacy)
+		return -ENOSYS;
+
+	for (i = 0; i < sizeof(pdata->enetaddr); i++) {
+		virtio_cwrite8(dev,
+			       offsetof(struct virtio_net_config, mac) + i,
+			       pdata->enetaddr[i]);
+	}
+
+	return 0;
+}
+
+static int virtio_net_read_rom_hwaddr(struct udevice *dev)
+{
+	struct eth_pdata *pdata = dev_get_platdata(dev);
+
+	if (!pdata)
+		return -ENOSYS;
+
+	if (virtio_has_feature(dev, VIRTIO_NET_F_MAC)) {
+		virtio_cread_bytes(dev,
+				   offsetof(struct virtio_net_config, mac),
+				   pdata->enetaddr, sizeof(pdata->enetaddr));
+	}
+
+	return 0;
+}
+
+static int virtio_net_bind(struct udevice *dev)
+{
+	struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(dev->parent);
+
+	/* Indicate what driver features we support */
+	virtio_driver_features_init(uc_priv, feature, ARRAY_SIZE(feature),
+				    feature_legacy, ARRAY_SIZE(feature_legacy));
+
+	return 0;
+}
+
+static int virtio_net_probe(struct udevice *dev)
+{
+	struct virtio_net_priv *priv = dev_get_priv(dev);
+	int ret;
+
+	ret = virtio_find_vqs(dev, 2, priv->vqs);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static const struct eth_ops virtio_net_ops = {
+	.start = virtio_net_start,
+	.send = virtio_net_send,
+	.recv = virtio_net_recv,
+	.free_pkt = virtio_net_free_pkt,
+	.stop = virtio_net_stop,
+	.write_hwaddr = virtio_net_write_hwaddr,
+	.read_rom_hwaddr = virtio_net_read_rom_hwaddr,
+};
+
+U_BOOT_DRIVER(virtio_net) = {
+	.name	= VIRTIO_NET_DRV_NAME,
+	.id	= UCLASS_ETH,
+	.bind	= virtio_net_bind,
+	.probe	= virtio_net_probe,
+	.remove = virtio_reset,
+	.ops	= &virtio_net_ops,
+	.priv_auto_alloc_size = sizeof(struct virtio_net_priv),
+	.platdata_auto_alloc_size = sizeof(struct eth_pdata),
+	.flags	= DM_FLAG_ACTIVE_DMA,
+};