From 7ffa7542eca6fa910edbecf13899cb74a699f37e Mon Sep 17 00:00:00 2001 From: Loic Poulain Date: Tue, 3 Aug 2021 15:36:29 +0200 Subject: net: mhi: Remove MBIM protocol The MBIM protocol has now been integrated in a proper WWAN driver. We can then revert back to a simpler driver for mhi_net, which is used for raw IP or QMAP protocol (via rmnet link). - Remove protocol management - Remove WWAN framework usage (only valid for mbim) - Remove net/mhi directory for simpler mhi_net.c file Signed-off-by: Loic Poulain Signed-off-by: David S. Miller --- drivers/net/mhi_net.c | 416 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 416 insertions(+) create mode 100644 drivers/net/mhi_net.c (limited to 'drivers/net/mhi_net.c') diff --git a/drivers/net/mhi_net.c b/drivers/net/mhi_net.c new file mode 100644 index 000000000000..d127eb6e9257 --- /dev/null +++ b/drivers/net/mhi_net.c @@ -0,0 +1,416 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* MHI Network driver - Network over MHI bus + * + * Copyright (C) 2020 Linaro Ltd + */ + +#include +#include +#include +#include +#include +#include +#include + +#define MHI_NET_MIN_MTU ETH_MIN_MTU +#define MHI_NET_MAX_MTU 0xffff +#define MHI_NET_DEFAULT_MTU 0x4000 + +struct mhi_net_stats { + u64_stats_t rx_packets; + u64_stats_t rx_bytes; + u64_stats_t rx_errors; + u64_stats_t tx_packets; + u64_stats_t tx_bytes; + u64_stats_t tx_errors; + u64_stats_t tx_dropped; + struct u64_stats_sync tx_syncp; + struct u64_stats_sync rx_syncp; +}; + +struct mhi_net_dev { + struct mhi_device *mdev; + struct net_device *ndev; + struct sk_buff *skbagg_head; + struct sk_buff *skbagg_tail; + struct delayed_work rx_refill; + struct mhi_net_stats stats; + u32 rx_queue_sz; + int msg_enable; + unsigned int mru; +}; + +struct mhi_device_info { + const char *netname; +}; + +static int mhi_ndo_open(struct net_device *ndev) +{ + struct mhi_net_dev *mhi_netdev = netdev_priv(ndev); + + /* Feed the rx buffer pool */ + schedule_delayed_work(&mhi_netdev->rx_refill, 0); + + /* Carrier is established via out-of-band channel (e.g. qmi) */ + netif_carrier_on(ndev); + + netif_start_queue(ndev); + + return 0; +} + +static int mhi_ndo_stop(struct net_device *ndev) +{ + struct mhi_net_dev *mhi_netdev = netdev_priv(ndev); + + netif_stop_queue(ndev); + netif_carrier_off(ndev); + cancel_delayed_work_sync(&mhi_netdev->rx_refill); + + return 0; +} + +static netdev_tx_t mhi_ndo_xmit(struct sk_buff *skb, struct net_device *ndev) +{ + struct mhi_net_dev *mhi_netdev = netdev_priv(ndev); + struct mhi_device *mdev = mhi_netdev->mdev; + int err; + + 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); + 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, + struct rtnl_link_stats64 *stats) +{ + struct mhi_net_dev *mhi_netdev = netdev_priv(ndev); + unsigned int start; + + do { + start = u64_stats_fetch_begin_irq(&mhi_netdev->stats.rx_syncp); + stats->rx_packets = u64_stats_read(&mhi_netdev->stats.rx_packets); + stats->rx_bytes = u64_stats_read(&mhi_netdev->stats.rx_bytes); + stats->rx_errors = u64_stats_read(&mhi_netdev->stats.rx_errors); + } while (u64_stats_fetch_retry_irq(&mhi_netdev->stats.rx_syncp, start)); + + do { + start = u64_stats_fetch_begin_irq(&mhi_netdev->stats.tx_syncp); + stats->tx_packets = u64_stats_read(&mhi_netdev->stats.tx_packets); + stats->tx_bytes = u64_stats_read(&mhi_netdev->stats.tx_bytes); + stats->tx_errors = u64_stats_read(&mhi_netdev->stats.tx_errors); + stats->tx_dropped = u64_stats_read(&mhi_netdev->stats.tx_dropped); + } while (u64_stats_fetch_retry_irq(&mhi_netdev->stats.tx_syncp, start)); +} + +static const struct net_device_ops mhi_netdev_ops = { + .ndo_open = mhi_ndo_open, + .ndo_stop = mhi_ndo_stop, + .ndo_start_xmit = mhi_ndo_xmit, + .ndo_get_stats64 = mhi_ndo_get_stats64, +}; + +static void mhi_net_setup(struct net_device *ndev) +{ + ndev->header_ops = NULL; /* No header */ + ndev->type = ARPHRD_RAWIP; + ndev->hard_header_len = 0; + ndev->addr_len = 0; + ndev->flags = IFF_POINTOPOINT | IFF_NOARP; + ndev->netdev_ops = &mhi_netdev_ops; + ndev->mtu = MHI_NET_DEFAULT_MTU; + ndev->min_mtu = MHI_NET_MIN_MTU; + ndev->max_mtu = MHI_NET_MAX_MTU; + ndev->tx_queue_len = 1000; +} + +static struct sk_buff *mhi_net_skb_agg(struct mhi_net_dev *mhi_netdev, + struct sk_buff *skb) +{ + struct sk_buff *head = mhi_netdev->skbagg_head; + struct sk_buff *tail = mhi_netdev->skbagg_tail; + + /* This is non-paged skb chaining using frag_list */ + if (!head) { + mhi_netdev->skbagg_head = skb; + return skb; + } + + if (!skb_shinfo(head)->frag_list) + skb_shinfo(head)->frag_list = skb; + else + tail->next = skb; + + head->len += skb->len; + head->data_len += skb->len; + head->truesize += skb->truesize; + + mhi_netdev->skbagg_tail = skb; + + return mhi_netdev->skbagg_head; +} + +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); + struct sk_buff *skb = mhi_res->buf_addr; + int free_desc_count; + + free_desc_count = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE); + + if (unlikely(mhi_res->transaction_status)) { + switch (mhi_res->transaction_status) { + case -EOVERFLOW: + /* Packet can not fit in one MHI buffer and has been + * split over multiple MHI transfers, do re-aggregation. + * That usually means the device side MTU is larger than + * the host side MTU/MRU. Since this is not optimal, + * print a warning (once). + */ + netdev_warn_once(mhi_netdev->ndev, + "Fragmented packets received, fix MTU?\n"); + skb_put(skb, mhi_res->bytes_xferd); + mhi_net_skb_agg(mhi_netdev, skb); + break; + case -ENOTCONN: + /* MHI layer stopping/resetting the DL channel */ + dev_kfree_skb_any(skb); + return; + default: + /* Unknown error, simply drop */ + dev_kfree_skb_any(skb); + u64_stats_update_begin(&mhi_netdev->stats.rx_syncp); + u64_stats_inc(&mhi_netdev->stats.rx_errors); + u64_stats_update_end(&mhi_netdev->stats.rx_syncp); + } + } else { + skb_put(skb, mhi_res->bytes_xferd); + + if (mhi_netdev->skbagg_head) { + /* Aggregate the final fragment */ + skb = mhi_net_skb_agg(mhi_netdev, skb); + mhi_netdev->skbagg_head = NULL; + } + + switch (skb->data[0] & 0xf0) { + case 0x40: + skb->protocol = htons(ETH_P_IP); + break; + case 0x60: + skb->protocol = htons(ETH_P_IPV6); + break; + default: + skb->protocol = htons(ETH_P_MAP); + break; + } + + u64_stats_update_begin(&mhi_netdev->stats.rx_syncp); + u64_stats_inc(&mhi_netdev->stats.rx_packets); + u64_stats_add(&mhi_netdev->stats.rx_bytes, skb->len); + u64_stats_update_end(&mhi_netdev->stats.rx_syncp); + netif_rx(skb); + } + + /* Refill if RX buffers queue becomes low */ + if (free_desc_count >= mhi_netdev->rx_queue_sz / 2) + schedule_delayed_work(&mhi_netdev->rx_refill, 0); +} + +static void mhi_net_ul_callback(struct mhi_device *mhi_dev, + struct mhi_result *mhi_res) +{ + struct mhi_net_dev *mhi_netdev = dev_get_drvdata(&mhi_dev->dev); + struct net_device *ndev = mhi_netdev->ndev; + struct mhi_device *mdev = mhi_netdev->mdev; + struct sk_buff *skb = mhi_res->buf_addr; + + /* Hardware has consumed the buffer, so free the skb (which is not + * freed by the MHI stack) and perform accounting. + */ + dev_consume_skb_any(skb); + + u64_stats_update_begin(&mhi_netdev->stats.tx_syncp); + if (unlikely(mhi_res->transaction_status)) { + /* MHI layer stopping/resetting the UL channel */ + if (mhi_res->transaction_status == -ENOTCONN) { + u64_stats_update_end(&mhi_netdev->stats.tx_syncp); + return; + } + + u64_stats_inc(&mhi_netdev->stats.tx_errors); + } else { + u64_stats_inc(&mhi_netdev->stats.tx_packets); + u64_stats_add(&mhi_netdev->stats.tx_bytes, mhi_res->bytes_xferd); + } + u64_stats_update_end(&mhi_netdev->stats.tx_syncp); + + if (netif_queue_stopped(ndev) && !mhi_queue_is_full(mdev, DMA_TO_DEVICE)) + netif_wake_queue(ndev); +} + +static void mhi_net_rx_refill_work(struct work_struct *work) +{ + struct mhi_net_dev *mhi_netdev = container_of(work, struct mhi_net_dev, + rx_refill.work); + struct net_device *ndev = mhi_netdev->ndev; + struct mhi_device *mdev = mhi_netdev->mdev; + struct sk_buff *skb; + unsigned int size; + int err; + + size = mhi_netdev->mru ? mhi_netdev->mru : READ_ONCE(ndev->mtu); + + while (!mhi_queue_is_full(mdev, DMA_FROM_DEVICE)) { + skb = netdev_alloc_skb(ndev, size); + if (unlikely(!skb)) + break; + + err = mhi_queue_skb(mdev, DMA_FROM_DEVICE, skb, size, MHI_EOT); + if (unlikely(err)) { + net_err_ratelimited("%s: Failed to queue RX buf (%d)\n", + ndev->name, err); + kfree_skb(skb); + break; + } + + /* Do not hog the CPU if rx buffers are consumed faster than + * queued (unlikely). + */ + cond_resched(); + } + + /* If we're still starved of rx buffers, reschedule later */ + if (mhi_get_free_desc_count(mdev, DMA_FROM_DEVICE) == mhi_netdev->rx_queue_sz) + schedule_delayed_work(&mhi_netdev->rx_refill, HZ / 2); +} + +static int mhi_net_newlink(struct mhi_device *mhi_dev, struct net_device *ndev) +{ + struct mhi_net_dev *mhi_netdev; + int err; + + mhi_netdev = netdev_priv(ndev); + + dev_set_drvdata(&mhi_dev->dev, mhi_netdev); + mhi_netdev->ndev = ndev; + mhi_netdev->mdev = mhi_dev; + mhi_netdev->skbagg_head = NULL; + mhi_netdev->mru = mhi_dev->mhi_cntrl->mru; + + INIT_DELAYED_WORK(&mhi_netdev->rx_refill, mhi_net_rx_refill_work); + u64_stats_init(&mhi_netdev->stats.rx_syncp); + u64_stats_init(&mhi_netdev->stats.tx_syncp); + + /* Start MHI channels */ + err = mhi_prepare_for_transfer(mhi_dev); + if (err) + goto out_err; + + /* Number of transfer descriptors determines size of the queue */ + mhi_netdev->rx_queue_sz = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE); + + err = register_netdev(ndev); + if (err) + return err; + + return 0; + +out_err: + free_netdev(ndev); + return err; +} + +static void mhi_net_dellink(struct mhi_device *mhi_dev, struct net_device *ndev) +{ + struct mhi_net_dev *mhi_netdev = netdev_priv(ndev); + + unregister_netdev(ndev); + + mhi_unprepare_from_transfer(mhi_dev); + + kfree_skb(mhi_netdev->skbagg_head); + + dev_set_drvdata(&mhi_dev->dev, NULL); +} + +static int mhi_net_probe(struct mhi_device *mhi_dev, + const struct mhi_device_id *id) +{ + const struct mhi_device_info *info = (struct mhi_device_info *)id->driver_data; + struct net_device *ndev; + int err; + + ndev = alloc_netdev(sizeof(struct mhi_net_dev), info->netname, + NET_NAME_PREDICTABLE, mhi_net_setup); + if (!ndev) + return -ENOMEM; + + SET_NETDEV_DEV(ndev, &mhi_dev->dev); + + err = mhi_net_newlink(mhi_dev, ndev); + if (err) { + free_netdev(ndev); + return err; + } + + return 0; +} + +static void mhi_net_remove(struct mhi_device *mhi_dev) +{ + struct mhi_net_dev *mhi_netdev = dev_get_drvdata(&mhi_dev->dev); + + mhi_net_dellink(mhi_dev, 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[] = { + /* 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); + +static struct mhi_driver mhi_net_driver = { + .probe = mhi_net_probe, + .remove = mhi_net_remove, + .dl_xfer_cb = mhi_net_dl_callback, + .ul_xfer_cb = mhi_net_ul_callback, + .id_table = mhi_net_id_table, + .driver = { + .name = "mhi_net", + .owner = THIS_MODULE, + }, +}; + +module_mhi_driver(mhi_net_driver); + +MODULE_AUTHOR("Loic Poulain "); +MODULE_DESCRIPTION("Network over MHI"); +MODULE_LICENSE("GPL v2"); -- cgit