xref: /openbmc/u-boot/drivers/virtio/virtio_net.c (revision 1d6edcbf)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2018, Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
4  * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
5  */
6 
7 #include <common.h>
8 #include <dm.h>
9 #include <net.h>
10 #include <virtio_types.h>
11 #include <virtio.h>
12 #include <virtio_ring.h>
13 #include "virtio_net.h"
14 
15 /* Amount of buffers to keep in the RX virtqueue */
16 #define VIRTIO_NET_NUM_RX_BUFS	32
17 
18 /*
19  * This value comes from the VirtIO spec: 1500 for maximum packet size,
20  * 14 for the Ethernet header, 12 for virtio_net_hdr. In total 1526 bytes.
21  */
22 #define VIRTIO_NET_RX_BUF_SIZE	1526
23 
24 struct virtio_net_priv {
25 	union {
26 		struct virtqueue *vqs[2];
27 		struct {
28 			struct virtqueue *rx_vq;
29 			struct virtqueue *tx_vq;
30 		};
31 	};
32 
33 	char rx_buff[VIRTIO_NET_NUM_RX_BUFS][VIRTIO_NET_RX_BUF_SIZE];
34 	bool rx_running;
35 	int net_hdr_len;
36 };
37 
38 /*
39  * For simplicity, the driver only negotiates the VIRTIO_NET_F_MAC feature.
40  * For the VIRTIO_NET_F_STATUS feature, we don't negotiate it, hence per spec
41  * we should assume the link is always active.
42  */
43 static const u32 feature[] = {
44 	VIRTIO_NET_F_MAC
45 };
46 
47 static const u32 feature_legacy[] = {
48 	VIRTIO_NET_F_MAC
49 };
50 
virtio_net_start(struct udevice * dev)51 static int virtio_net_start(struct udevice *dev)
52 {
53 	struct virtio_net_priv *priv = dev_get_priv(dev);
54 	struct virtio_sg sg;
55 	struct virtio_sg *sgs[] = { &sg };
56 	int i;
57 
58 	if (!priv->rx_running) {
59 		/* receive buffer length is always 1526 */
60 		sg.length = VIRTIO_NET_RX_BUF_SIZE;
61 
62 		/* setup the receive buffer address */
63 		for (i = 0; i < VIRTIO_NET_NUM_RX_BUFS; i++) {
64 			sg.addr = priv->rx_buff[i];
65 			virtqueue_add(priv->rx_vq, sgs, 0, 1);
66 		}
67 
68 		virtqueue_kick(priv->rx_vq);
69 
70 		/* setup the receive queue only once */
71 		priv->rx_running = true;
72 	}
73 
74 	return 0;
75 }
76 
virtio_net_send(struct udevice * dev,void * packet,int length)77 static int virtio_net_send(struct udevice *dev, void *packet, int length)
78 {
79 	struct virtio_net_priv *priv = dev_get_priv(dev);
80 	struct virtio_net_hdr hdr;
81 	struct virtio_net_hdr_v1 hdr_v1;
82 	struct virtio_sg hdr_sg;
83 	struct virtio_sg data_sg = { packet, length };
84 	struct virtio_sg *sgs[] = { &hdr_sg, &data_sg };
85 	int ret;
86 
87 	if (priv->net_hdr_len == sizeof(struct virtio_net_hdr))
88 		hdr_sg.addr = &hdr;
89 	else
90 		hdr_sg.addr = &hdr_v1;
91 	hdr_sg.length = priv->net_hdr_len;
92 
93 	memset(hdr_sg.addr, 0, priv->net_hdr_len);
94 
95 	ret = virtqueue_add(priv->tx_vq, sgs, 2, 0);
96 	if (ret)
97 		return ret;
98 
99 	virtqueue_kick(priv->tx_vq);
100 
101 	while (1) {
102 		if (virtqueue_get_buf(priv->tx_vq, NULL))
103 			break;
104 	}
105 
106 	return 0;
107 }
108 
virtio_net_recv(struct udevice * dev,int flags,uchar ** packetp)109 static int virtio_net_recv(struct udevice *dev, int flags, uchar **packetp)
110 {
111 	struct virtio_net_priv *priv = dev_get_priv(dev);
112 	unsigned int len;
113 	void *buf;
114 
115 	buf = virtqueue_get_buf(priv->rx_vq, &len);
116 	if (!buf)
117 		return -EAGAIN;
118 
119 	*packetp = buf + priv->net_hdr_len;
120 	return len - priv->net_hdr_len;
121 }
122 
virtio_net_free_pkt(struct udevice * dev,uchar * packet,int length)123 static int virtio_net_free_pkt(struct udevice *dev, uchar *packet, int length)
124 {
125 	struct virtio_net_priv *priv = dev_get_priv(dev);
126 	void *buf = packet - priv->net_hdr_len;
127 	struct virtio_sg sg = { buf, VIRTIO_NET_RX_BUF_SIZE };
128 	struct virtio_sg *sgs[] = { &sg };
129 
130 	/* Put the buffer back to the rx ring */
131 	virtqueue_add(priv->rx_vq, sgs, 0, 1);
132 
133 	return 0;
134 }
135 
virtio_net_stop(struct udevice * dev)136 static void virtio_net_stop(struct udevice *dev)
137 {
138 	/*
139 	 * There is no way to stop the queue from running, unless we issue
140 	 * a reset to the virtio device, and re-do the queue initialization
141 	 * from the beginning.
142 	 */
143 }
144 
virtio_net_write_hwaddr(struct udevice * dev)145 static int virtio_net_write_hwaddr(struct udevice *dev)
146 {
147 	struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(dev->parent);
148 	struct eth_pdata *pdata = dev_get_platdata(dev);
149 	int i;
150 
151 	/*
152 	 * v1.0 compliant device's MAC address is set through control channel,
153 	 * which we don't support for now.
154 	 */
155 	if (!uc_priv->legacy)
156 		return -ENOSYS;
157 
158 	for (i = 0; i < sizeof(pdata->enetaddr); i++) {
159 		virtio_cwrite8(dev,
160 			       offsetof(struct virtio_net_config, mac) + i,
161 			       pdata->enetaddr[i]);
162 	}
163 
164 	return 0;
165 }
166 
virtio_net_read_rom_hwaddr(struct udevice * dev)167 static int virtio_net_read_rom_hwaddr(struct udevice *dev)
168 {
169 	struct eth_pdata *pdata = dev_get_platdata(dev);
170 
171 	if (!pdata)
172 		return -ENOSYS;
173 
174 	if (virtio_has_feature(dev, VIRTIO_NET_F_MAC)) {
175 		virtio_cread_bytes(dev,
176 				   offsetof(struct virtio_net_config, mac),
177 				   pdata->enetaddr, sizeof(pdata->enetaddr));
178 	}
179 
180 	return 0;
181 }
182 
virtio_net_bind(struct udevice * dev)183 static int virtio_net_bind(struct udevice *dev)
184 {
185 	struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(dev->parent);
186 
187 	/* Indicate what driver features we support */
188 	virtio_driver_features_init(uc_priv, feature, ARRAY_SIZE(feature),
189 				    feature_legacy, ARRAY_SIZE(feature_legacy));
190 
191 	return 0;
192 }
193 
virtio_net_probe(struct udevice * dev)194 static int virtio_net_probe(struct udevice *dev)
195 {
196 	struct virtio_net_priv *priv = dev_get_priv(dev);
197 	struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(dev->parent);
198 	int ret;
199 
200 	ret = virtio_find_vqs(dev, 2, priv->vqs);
201 	if (ret < 0)
202 		return ret;
203 
204 	/*
205 	 * For v1.0 compliant device, it always assumes the member
206 	 * 'num_buffers' exists in the struct virtio_net_hdr while
207 	 * the legacy driver only presented 'num_buffers' when
208 	 * VIRTIO_NET_F_MRG_RXBUF was negotiated. Without that feature
209 	 * the structure was 2 bytes shorter.
210 	 */
211 	if (uc_priv->legacy)
212 		priv->net_hdr_len = sizeof(struct virtio_net_hdr);
213 	else
214 		priv->net_hdr_len = sizeof(struct virtio_net_hdr_v1);
215 
216 	return 0;
217 }
218 
219 static const struct eth_ops virtio_net_ops = {
220 	.start = virtio_net_start,
221 	.send = virtio_net_send,
222 	.recv = virtio_net_recv,
223 	.free_pkt = virtio_net_free_pkt,
224 	.stop = virtio_net_stop,
225 	.write_hwaddr = virtio_net_write_hwaddr,
226 	.read_rom_hwaddr = virtio_net_read_rom_hwaddr,
227 };
228 
229 U_BOOT_DRIVER(virtio_net) = {
230 	.name	= VIRTIO_NET_DRV_NAME,
231 	.id	= UCLASS_ETH,
232 	.bind	= virtio_net_bind,
233 	.probe	= virtio_net_probe,
234 	.remove = virtio_reset,
235 	.ops	= &virtio_net_ops,
236 	.priv_auto_alloc_size = sizeof(struct virtio_net_priv),
237 	.platdata_auto_alloc_size = sizeof(struct eth_pdata),
238 	.flags	= DM_FLAG_ACTIVE_DMA,
239 };
240