net: Add mhi-net driver (3ffec6a1) · Commits · 戴 / test

drivers/net/Kconfig

+7 −0

Original line number	Diff line number	Diff line
		@@ -426,6 +426,13 @@ config VSOCKMON
		mostly intended for developers or support to debug vsock issues. If
		unsure, say N.

		config MHI_NET
		tristate "MHI network driver"
		depends on MHI_BUS
		help
		This is the network driver for MHI bus. It can be used with
		QCOM based WWAN modems (like SDX55). Say Y or M.

		endif # NET_CORE

		config SUNGEM_PHY

drivers/net/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -36,6 +36,7 @@ obj-$(CONFIG_GTP) += gtp.o
		obj-$(CONFIG_NLMON) += nlmon.o
		obj-$(CONFIG_NET_VRF) += vrf.o
		obj-$(CONFIG_VSOCKMON) += vsockmon.o
		obj-$(CONFIG_MHI_NET) += mhi_net.o

		#
		# Networking Drivers

drivers/net/mhi_net.c

0 → 100644

+316 −0

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0-or-later
		/* MHI Network driver - Network over MHI bus
		*
		* Copyright (C) 2020 Linaro Ltd <loic.poulain@linaro.org>
		*/

		#include <linux/if_arp.h>
		#include <linux/mhi.h>
		#include <linux/mod_devicetable.h>
		#include <linux/module.h>
		#include <linux/netdevice.h>
		#include <linux/skbuff.h>
		#include <linux/u64_stats_sync.h>

		#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 rx_dropped;
		u64_stats_t tx_packets;
		u64_stats_t tx_bytes;
		u64_stats_t tx_errors;
		u64_stats_t tx_dropped;
		atomic_t rx_queued;
		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 delayed_work rx_refill;
		struct mhi_net_stats stats;
		u32 rx_queue_sz;
		};

		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 int 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);

		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);
		}

		if (mhi_queue_is_full(mdev, DMA_TO_DEVICE))
		netif_stop_queue(ndev);

		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);
		stats->rx_dropped = u64_stats_read(&mhi_netdev->stats.rx_dropped);
		} 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_NONE; /* QMAP... */
		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 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 remaining;

		remaining = atomic_dec_return(&mhi_netdev->stats.rx_queued);

		if (unlikely(mhi_res->transaction_status)) {
		dev_kfree_skb_any(skb);

		/* MHI layer stopping/resetting the DL channel */
		if (mhi_res->transaction_status == -ENOTCONN)
		return;

		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 {
		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, mhi_res->bytes_xferd);
		u64_stats_update_end(&mhi_netdev->stats.rx_syncp);

		skb->protocol = htons(ETH_P_MAP);
		skb_put(skb, mhi_res->bytes_xferd);
		netif_rx(skb);
		}

		/* Refill if RX buffers queue becomes low */
		if (remaining <= 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 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))
		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;
		int size = READ_ONCE(ndev->mtu);
		struct sk_buff *skb;
		int err;

		while (atomic_read(&mhi_netdev->stats.rx_queued) < mhi_netdev->rx_queue_sz) {
		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;
		}

		atomic_inc(&mhi_netdev->stats.rx_queued);

		/* 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 (unlikely(!atomic_read(&mhi_netdev->stats.rx_queued)))
		schedule_delayed_work(&mhi_netdev->rx_refill, HZ / 2);
		}

		static int mhi_net_probe(struct mhi_device *mhi_dev,
		const struct mhi_device_id *id)
		{
		const char netname = (char )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);
		if (!ndev)
		return -ENOMEM;

		mhi_netdev = netdev_priv(ndev);
		dev_set_drvdata(dev, mhi_netdev);
		mhi_netdev->ndev = ndev;
		mhi_netdev->mdev = mhi_dev;
		SET_NETDEV_DEV(ndev, &mhi_dev->dev);

		/* All MHI net channels have 128 ring elements (at least for now) */
		mhi_netdev->rx_queue_sz = 128;

		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;

		err = register_netdev(ndev);
		if (err)
		goto out_err;

		return 0;

		out_err:
		free_netdev(ndev);
		return err;
		}

		static void mhi_net_remove(struct mhi_device *mhi_dev)
		{
		struct mhi_net_dev *mhi_netdev = dev_get_drvdata(&mhi_dev->dev);

		unregister_netdev(mhi_netdev->ndev);

		mhi_unprepare_from_transfer(mhi_netdev->mdev);

		free_netdev(mhi_netdev->ndev);
		}

		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" },
		{}
		};
		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 <loic.poulain@linaro.org>");
		MODULE_DESCRIPTION("Network over MHI");
		MODULE_LICENSE("GPL v2");

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