net: mhi: Add protocol support

MHI can transport different protocols, some are handled at upper level,
like IP and QMAP(rmnet/netlink), but others will need to be inside MHI
net driver, like mbim. This change adds support for protocol rx and
tx_fixup callbacks registration, that can be used to encode/decode the
targeted protocol.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/mhi_net.c b/drivers/net/mhi_net.c
index 8800991..b92c2e1 100644 (file)
--- a/drivers/net/mhi_net.c
+++ b/drivers/net/mhi_net.c
@@ -34,11 +34,24 @@ struct mhi_net_dev {
        struct net_device *ndev;
        struct sk_buff *skbagg_head;
        struct sk_buff *skbagg_tail;
+       const struct mhi_net_proto *proto;
+       void *proto_data;
        struct delayed_work rx_refill;
        struct mhi_net_stats stats;
        u32 rx_queue_sz;
 };
 
+struct mhi_net_proto {
+       int (*init)(struct mhi_net_dev *mhi_netdev);
+       struct sk_buff * (*tx_fixup)(struct mhi_net_dev *mhi_netdev, struct sk_buff *skb);
+       void (*rx)(struct mhi_net_dev *mhi_netdev, struct sk_buff *skb);
+};
+
+struct mhi_device_info {
+       const char *netname;
+       const struct mhi_net_proto *proto;
+};
+
 static int mhi_ndo_open(struct net_device *ndev)
 {
        struct mhi_net_dev *mhi_netdev = netdev_priv(ndev);
@@ -68,26 +81,35 @@ static int mhi_ndo_stop(struct net_device *ndev)
 static int mhi_ndo_xmit(struct sk_buff *skb, struct net_device *ndev)
 {
        struct mhi_net_dev *mhi_netdev = netdev_priv(ndev);
+       const struct mhi_net_proto *proto = mhi_netdev->proto;
        struct mhi_device *mdev = mhi_netdev->mdev;
        int err;
 
+       if (proto && proto->tx_fixup) {
+               skb = proto->tx_fixup(mhi_netdev, skb);
+               if (unlikely(!skb))
+                       goto exit_drop;
+       }
+
        err = mhi_queue_skb(mdev, DMA_TO_DEVICE, skb, skb->len, MHI_EOT);
        if (unlikely(err)) {
                net_err_ratelimited("%s: Failed to queue TX buf (%d)\n",
                                    ndev->name, err);
-
-               u64_stats_update_begin(&mhi_netdev->stats.tx_syncp);
-               u64_stats_inc(&mhi_netdev->stats.tx_dropped);
-               u64_stats_update_end(&mhi_netdev->stats.tx_syncp);
-
-               /* drop the packet */
                dev_kfree_skb_any(skb);
+               goto exit_drop;
        }
 
        if (mhi_queue_is_full(mdev, DMA_TO_DEVICE))
                netif_stop_queue(ndev);
 
        return NETDEV_TX_OK;
+
+exit_drop:
+       u64_stats_update_begin(&mhi_netdev->stats.tx_syncp);
+       u64_stats_inc(&mhi_netdev->stats.tx_dropped);
+       u64_stats_update_end(&mhi_netdev->stats.tx_syncp);
+
+       return NETDEV_TX_OK;
 }
 
 static void mhi_ndo_get_stats64(struct net_device *ndev,
@@ -164,6 +186,7 @@ static void mhi_net_dl_callback(struct mhi_device *mhi_dev,
                                struct mhi_result *mhi_res)
 {
        struct mhi_net_dev *mhi_netdev = dev_get_drvdata(&mhi_dev->dev);
+       const struct mhi_net_proto *proto = mhi_netdev->proto;
        struct sk_buff *skb = mhi_res->buf_addr;
        int free_desc_count;
 
@@ -220,7 +243,10 @@ static void mhi_net_dl_callback(struct mhi_device *mhi_dev,
                        break;
                }
 
-               netif_rx(skb);
+               if (proto && proto->rx)
+                       proto->rx(mhi_netdev, skb);
+               else
+                       netif_rx(skb);
        }
 
        /* Refill if RX buffers queue becomes low */
@@ -302,14 +328,14 @@ static struct device_type wwan_type = {
 static int mhi_net_probe(struct mhi_device *mhi_dev,
                         const struct mhi_device_id *id)
 {
-       const char *netname = (char *)id->driver_data;
+       const struct mhi_device_info *info = (struct mhi_device_info *)id->driver_data;
        struct device *dev = &mhi_dev->dev;
        struct mhi_net_dev *mhi_netdev;
        struct net_device *ndev;
        int err;
 
-       ndev = alloc_netdev(sizeof(*mhi_netdev), netname, NET_NAME_PREDICTABLE,
-                           mhi_net_setup);
+       ndev = alloc_netdev(sizeof(*mhi_netdev), info->netname,
+                           NET_NAME_PREDICTABLE, mhi_net_setup);
        if (!ndev)
                return -ENOMEM;
 
@@ -318,6 +344,7 @@ static int mhi_net_probe(struct mhi_device *mhi_dev,
        mhi_netdev->ndev = ndev;
        mhi_netdev->mdev = mhi_dev;
        mhi_netdev->skbagg_head = NULL;
+       mhi_netdev->proto = info->proto;
        SET_NETDEV_DEV(ndev, &mhi_dev->dev);
        SET_NETDEV_DEVTYPE(ndev, &wwan_type);
 
@@ -337,8 +364,16 @@ static int mhi_net_probe(struct mhi_device *mhi_dev,
        if (err)
                goto out_err;
 
+       if (mhi_netdev->proto) {
+               err = mhi_netdev->proto->init(mhi_netdev);
+               if (err)
+                       goto out_err_proto;
+       }
+
        return 0;
 
+out_err_proto:
+       unregister_netdev(ndev);
 out_err:
        free_netdev(ndev);
        return err;
@@ -358,9 +393,19 @@ static void mhi_net_remove(struct mhi_device *mhi_dev)
        free_netdev(mhi_netdev->ndev);
 }
 
+static const struct mhi_device_info mhi_hwip0 = {
+       .netname = "mhi_hwip%d",
+};
+
+static const struct mhi_device_info mhi_swip0 = {
+       .netname = "mhi_swip%d",
+};
+
 static const struct mhi_device_id mhi_net_id_table[] = {
-       { .chan = "IP_HW0", .driver_data = (kernel_ulong_t)"mhi_hwip%d" },
-       { .chan = "IP_SW0", .driver_data = (kernel_ulong_t)"mhi_swip%d" },
+       /* Hardware accelerated data PATH (to modem IPA), protocol agnostic */
+       { .chan = "IP_HW0", .driver_data = (kernel_ulong_t)&mhi_hwip0 },
+       /* Software data PATH (to modem CPU) */
+       { .chan = "IP_SW0", .driver_data = (kernel_ulong_t)&mhi_swip0 },
        {}
 };
 MODULE_DEVICE_TABLE(mhi, mhi_net_id_table);