LXR uboot/drivers/virtio/virtio

   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
  24struct 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 */
  43static const u32 feature[] = {
  44        VIRTIO_NET_F_MAC
  45};
  46
  47static const u32 feature_legacy[] = {
  48        VIRTIO_NET_F_MAC
  49};
  50
  51static 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
  77static 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
 109static 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
 123static 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
 136static 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
 145static 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
 167static 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
 183static 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
 194static 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
 219static 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
 229U_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