415 lines
11 KiB
C
415 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* MHI Network driver - Network over MHI bus
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*
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* Copyright (C) 2020 Linaro Ltd <loic.poulain@linaro.org>
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*/
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#include <linux/if_arp.h>
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#include <linux/mhi.h>
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include <linux/u64_stats_sync.h>
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#define MHI_NET_MIN_MTU ETH_MIN_MTU
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#define MHI_NET_MAX_MTU 0xffff
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#define MHI_NET_DEFAULT_MTU 0x4000
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struct mhi_net_stats {
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u64_stats_t rx_packets;
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u64_stats_t rx_bytes;
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u64_stats_t rx_errors;
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u64_stats_t tx_packets;
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u64_stats_t tx_bytes;
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u64_stats_t tx_errors;
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u64_stats_t tx_dropped;
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struct u64_stats_sync tx_syncp;
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struct u64_stats_sync rx_syncp;
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};
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struct mhi_net_dev {
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struct mhi_device *mdev;
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struct net_device *ndev;
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struct sk_buff *skbagg_head;
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struct sk_buff *skbagg_tail;
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struct delayed_work rx_refill;
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struct mhi_net_stats stats;
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u32 rx_queue_sz;
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int msg_enable;
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unsigned int mru;
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};
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struct mhi_device_info {
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const char *netname;
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};
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static int mhi_ndo_open(struct net_device *ndev)
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{
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struct mhi_net_dev *mhi_netdev = netdev_priv(ndev);
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/* Feed the rx buffer pool */
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schedule_delayed_work(&mhi_netdev->rx_refill, 0);
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/* Carrier is established via out-of-band channel (e.g. qmi) */
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netif_carrier_on(ndev);
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netif_start_queue(ndev);
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return 0;
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}
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static int mhi_ndo_stop(struct net_device *ndev)
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{
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struct mhi_net_dev *mhi_netdev = netdev_priv(ndev);
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netif_stop_queue(ndev);
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netif_carrier_off(ndev);
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cancel_delayed_work_sync(&mhi_netdev->rx_refill);
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return 0;
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}
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static netdev_tx_t mhi_ndo_xmit(struct sk_buff *skb, struct net_device *ndev)
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{
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struct mhi_net_dev *mhi_netdev = netdev_priv(ndev);
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struct mhi_device *mdev = mhi_netdev->mdev;
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int err;
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err = mhi_queue_skb(mdev, DMA_TO_DEVICE, skb, skb->len, MHI_EOT);
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if (unlikely(err)) {
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net_err_ratelimited("%s: Failed to queue TX buf (%d)\n",
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ndev->name, err);
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dev_kfree_skb_any(skb);
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goto exit_drop;
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}
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if (mhi_queue_is_full(mdev, DMA_TO_DEVICE))
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netif_stop_queue(ndev);
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return NETDEV_TX_OK;
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exit_drop:
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u64_stats_update_begin(&mhi_netdev->stats.tx_syncp);
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u64_stats_inc(&mhi_netdev->stats.tx_dropped);
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u64_stats_update_end(&mhi_netdev->stats.tx_syncp);
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return NETDEV_TX_OK;
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}
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static void mhi_ndo_get_stats64(struct net_device *ndev,
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struct rtnl_link_stats64 *stats)
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{
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struct mhi_net_dev *mhi_netdev = netdev_priv(ndev);
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unsigned int start;
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do {
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start = u64_stats_fetch_begin(&mhi_netdev->stats.rx_syncp);
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stats->rx_packets = u64_stats_read(&mhi_netdev->stats.rx_packets);
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stats->rx_bytes = u64_stats_read(&mhi_netdev->stats.rx_bytes);
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stats->rx_errors = u64_stats_read(&mhi_netdev->stats.rx_errors);
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} while (u64_stats_fetch_retry(&mhi_netdev->stats.rx_syncp, start));
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do {
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start = u64_stats_fetch_begin(&mhi_netdev->stats.tx_syncp);
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stats->tx_packets = u64_stats_read(&mhi_netdev->stats.tx_packets);
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stats->tx_bytes = u64_stats_read(&mhi_netdev->stats.tx_bytes);
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stats->tx_errors = u64_stats_read(&mhi_netdev->stats.tx_errors);
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stats->tx_dropped = u64_stats_read(&mhi_netdev->stats.tx_dropped);
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} while (u64_stats_fetch_retry(&mhi_netdev->stats.tx_syncp, start));
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}
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static const struct net_device_ops mhi_netdev_ops = {
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.ndo_open = mhi_ndo_open,
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.ndo_stop = mhi_ndo_stop,
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.ndo_start_xmit = mhi_ndo_xmit,
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.ndo_get_stats64 = mhi_ndo_get_stats64,
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};
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static void mhi_net_setup(struct net_device *ndev)
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{
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ndev->header_ops = NULL; /* No header */
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ndev->type = ARPHRD_RAWIP;
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ndev->hard_header_len = 0;
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ndev->addr_len = 0;
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ndev->flags = IFF_POINTOPOINT | IFF_NOARP;
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ndev->netdev_ops = &mhi_netdev_ops;
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ndev->mtu = MHI_NET_DEFAULT_MTU;
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ndev->min_mtu = MHI_NET_MIN_MTU;
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ndev->max_mtu = MHI_NET_MAX_MTU;
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ndev->tx_queue_len = 1000;
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}
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static struct sk_buff *mhi_net_skb_agg(struct mhi_net_dev *mhi_netdev,
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struct sk_buff *skb)
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{
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struct sk_buff *head = mhi_netdev->skbagg_head;
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struct sk_buff *tail = mhi_netdev->skbagg_tail;
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/* This is non-paged skb chaining using frag_list */
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if (!head) {
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mhi_netdev->skbagg_head = skb;
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return skb;
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}
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if (!skb_shinfo(head)->frag_list)
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skb_shinfo(head)->frag_list = skb;
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else
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tail->next = skb;
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head->len += skb->len;
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head->data_len += skb->len;
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head->truesize += skb->truesize;
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mhi_netdev->skbagg_tail = skb;
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return mhi_netdev->skbagg_head;
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}
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static void mhi_net_dl_callback(struct mhi_device *mhi_dev,
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struct mhi_result *mhi_res)
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{
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struct mhi_net_dev *mhi_netdev = dev_get_drvdata(&mhi_dev->dev);
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struct sk_buff *skb = mhi_res->buf_addr;
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int free_desc_count;
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free_desc_count = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE);
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if (unlikely(mhi_res->transaction_status)) {
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switch (mhi_res->transaction_status) {
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case -EOVERFLOW:
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/* Packet can not fit in one MHI buffer and has been
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* split over multiple MHI transfers, do re-aggregation.
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* That usually means the device side MTU is larger than
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* the host side MTU/MRU. Since this is not optimal,
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* print a warning (once).
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*/
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netdev_warn_once(mhi_netdev->ndev,
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"Fragmented packets received, fix MTU?\n");
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skb_put(skb, mhi_res->bytes_xferd);
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mhi_net_skb_agg(mhi_netdev, skb);
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break;
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case -ENOTCONN:
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/* MHI layer stopping/resetting the DL channel */
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dev_kfree_skb_any(skb);
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return;
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default:
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/* Unknown error, simply drop */
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dev_kfree_skb_any(skb);
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u64_stats_update_begin(&mhi_netdev->stats.rx_syncp);
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u64_stats_inc(&mhi_netdev->stats.rx_errors);
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u64_stats_update_end(&mhi_netdev->stats.rx_syncp);
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}
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} else {
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skb_put(skb, mhi_res->bytes_xferd);
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if (mhi_netdev->skbagg_head) {
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/* Aggregate the final fragment */
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skb = mhi_net_skb_agg(mhi_netdev, skb);
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mhi_netdev->skbagg_head = NULL;
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}
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switch (skb->data[0] & 0xf0) {
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case 0x40:
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skb->protocol = htons(ETH_P_IP);
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break;
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case 0x60:
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skb->protocol = htons(ETH_P_IPV6);
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break;
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default:
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skb->protocol = htons(ETH_P_MAP);
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break;
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}
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u64_stats_update_begin(&mhi_netdev->stats.rx_syncp);
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u64_stats_inc(&mhi_netdev->stats.rx_packets);
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u64_stats_add(&mhi_netdev->stats.rx_bytes, skb->len);
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u64_stats_update_end(&mhi_netdev->stats.rx_syncp);
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__netif_rx(skb);
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}
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/* Refill if RX buffers queue becomes low */
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if (free_desc_count >= mhi_netdev->rx_queue_sz / 2)
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schedule_delayed_work(&mhi_netdev->rx_refill, 0);
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}
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static void mhi_net_ul_callback(struct mhi_device *mhi_dev,
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struct mhi_result *mhi_res)
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{
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struct mhi_net_dev *mhi_netdev = dev_get_drvdata(&mhi_dev->dev);
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struct net_device *ndev = mhi_netdev->ndev;
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struct mhi_device *mdev = mhi_netdev->mdev;
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struct sk_buff *skb = mhi_res->buf_addr;
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/* Hardware has consumed the buffer, so free the skb (which is not
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* freed by the MHI stack) and perform accounting.
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*/
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dev_consume_skb_any(skb);
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u64_stats_update_begin(&mhi_netdev->stats.tx_syncp);
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if (unlikely(mhi_res->transaction_status)) {
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/* MHI layer stopping/resetting the UL channel */
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if (mhi_res->transaction_status == -ENOTCONN) {
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u64_stats_update_end(&mhi_netdev->stats.tx_syncp);
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return;
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}
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u64_stats_inc(&mhi_netdev->stats.tx_errors);
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} else {
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u64_stats_inc(&mhi_netdev->stats.tx_packets);
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u64_stats_add(&mhi_netdev->stats.tx_bytes, mhi_res->bytes_xferd);
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}
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u64_stats_update_end(&mhi_netdev->stats.tx_syncp);
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if (netif_queue_stopped(ndev) && !mhi_queue_is_full(mdev, DMA_TO_DEVICE))
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netif_wake_queue(ndev);
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}
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static void mhi_net_rx_refill_work(struct work_struct *work)
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{
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struct mhi_net_dev *mhi_netdev = container_of(work, struct mhi_net_dev,
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rx_refill.work);
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struct net_device *ndev = mhi_netdev->ndev;
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struct mhi_device *mdev = mhi_netdev->mdev;
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struct sk_buff *skb;
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unsigned int size;
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int err;
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size = mhi_netdev->mru ? mhi_netdev->mru : READ_ONCE(ndev->mtu);
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while (!mhi_queue_is_full(mdev, DMA_FROM_DEVICE)) {
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skb = netdev_alloc_skb(ndev, size);
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if (unlikely(!skb))
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break;
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err = mhi_queue_skb(mdev, DMA_FROM_DEVICE, skb, size, MHI_EOT);
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if (unlikely(err)) {
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net_err_ratelimited("%s: Failed to queue RX buf (%d)\n",
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ndev->name, err);
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kfree_skb(skb);
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break;
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}
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/* Do not hog the CPU if rx buffers are consumed faster than
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* queued (unlikely).
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*/
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cond_resched();
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}
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/* If we're still starved of rx buffers, reschedule later */
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if (mhi_get_free_desc_count(mdev, DMA_FROM_DEVICE) == mhi_netdev->rx_queue_sz)
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schedule_delayed_work(&mhi_netdev->rx_refill, HZ / 2);
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}
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static int mhi_net_newlink(struct mhi_device *mhi_dev, struct net_device *ndev)
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{
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struct mhi_net_dev *mhi_netdev;
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int err;
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mhi_netdev = netdev_priv(ndev);
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dev_set_drvdata(&mhi_dev->dev, mhi_netdev);
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mhi_netdev->ndev = ndev;
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mhi_netdev->mdev = mhi_dev;
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mhi_netdev->skbagg_head = NULL;
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mhi_netdev->mru = mhi_dev->mhi_cntrl->mru;
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INIT_DELAYED_WORK(&mhi_netdev->rx_refill, mhi_net_rx_refill_work);
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u64_stats_init(&mhi_netdev->stats.rx_syncp);
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u64_stats_init(&mhi_netdev->stats.tx_syncp);
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/* Start MHI channels */
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err = mhi_prepare_for_transfer(mhi_dev);
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if (err)
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return err;
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/* Number of transfer descriptors determines size of the queue */
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mhi_netdev->rx_queue_sz = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE);
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err = register_netdev(ndev);
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if (err)
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return err;
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return 0;
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}
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static void mhi_net_dellink(struct mhi_device *mhi_dev, struct net_device *ndev)
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{
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struct mhi_net_dev *mhi_netdev = netdev_priv(ndev);
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unregister_netdev(ndev);
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mhi_unprepare_from_transfer(mhi_dev);
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kfree_skb(mhi_netdev->skbagg_head);
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free_netdev(ndev);
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dev_set_drvdata(&mhi_dev->dev, NULL);
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}
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static int mhi_net_probe(struct mhi_device *mhi_dev,
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const struct mhi_device_id *id)
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{
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const struct mhi_device_info *info = (struct mhi_device_info *)id->driver_data;
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struct net_device *ndev;
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int err;
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ndev = alloc_netdev(sizeof(struct mhi_net_dev), info->netname,
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NET_NAME_PREDICTABLE, mhi_net_setup);
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if (!ndev)
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return -ENOMEM;
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SET_NETDEV_DEV(ndev, &mhi_dev->dev);
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err = mhi_net_newlink(mhi_dev, ndev);
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if (err) {
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free_netdev(ndev);
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return err;
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}
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return 0;
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}
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static void mhi_net_remove(struct mhi_device *mhi_dev)
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{
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struct mhi_net_dev *mhi_netdev = dev_get_drvdata(&mhi_dev->dev);
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mhi_net_dellink(mhi_dev, mhi_netdev->ndev);
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}
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static const struct mhi_device_info mhi_hwip0 = {
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.netname = "mhi_hwip%d",
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};
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static const struct mhi_device_info mhi_swip0 = {
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.netname = "mhi_swip%d",
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};
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static const struct mhi_device_id mhi_net_id_table[] = {
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/* Hardware accelerated data PATH (to modem IPA), protocol agnostic */
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{ .chan = "IP_HW0", .driver_data = (kernel_ulong_t)&mhi_hwip0 },
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/* Software data PATH (to modem CPU) */
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{ .chan = "IP_SW0", .driver_data = (kernel_ulong_t)&mhi_swip0 },
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{}
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};
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MODULE_DEVICE_TABLE(mhi, mhi_net_id_table);
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static struct mhi_driver mhi_net_driver = {
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.probe = mhi_net_probe,
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.remove = mhi_net_remove,
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.dl_xfer_cb = mhi_net_dl_callback,
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.ul_xfer_cb = mhi_net_ul_callback,
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.id_table = mhi_net_id_table,
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.driver = {
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.name = "mhi_net",
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.owner = THIS_MODULE,
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},
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};
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module_mhi_driver(mhi_net_driver);
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MODULE_AUTHOR("Loic Poulain <loic.poulain@linaro.org>");
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MODULE_DESCRIPTION("Network over MHI");
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MODULE_LICENSE("GPL v2");
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