[linux-2.6-block.git] / drivers / net / mhi / net.c

// 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>
#include <linux/wwan.h>

#include "mhi.h"

#define MHI_NET_MIN_MTU		ETH_MIN_MTU
#define MHI_NET_MAX_MTU		0xffff
#define MHI_NET_DEFAULT_MTU	0x4000

/* When set to false, the default netdev (link 0) is not created, and it's up
 * to user to create the link (via wwan rtnetlink).
 */
static bool create_default_iface = true;
module_param(create_default_iface, bool, 0);

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 = wwan_netdev_drvpriv(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 = wwan_netdev_drvpriv(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 = wwan_netdev_drvpriv(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);
		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 = wwan_netdev_drvpriv(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);
		stats->rx_length_errors = u64_stats_read(&mhi_netdev->stats.rx_length_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);
	const struct mhi_net_proto *proto = mhi_netdev->proto;
	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;
		}

		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);

		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;
		}

		if (proto && proto->rx)
			proto->rx(mhi_netdev, skb);
		else
			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(void *ctxt, struct net_device *ndev, u32 if_id,
			   struct netlink_ext_ack *extack)
{
	const struct mhi_device_info *info;
	struct mhi_device *mhi_dev = ctxt;
	struct mhi_net_dev *mhi_netdev;
	int err;

	info = (struct mhi_device_info *)mhi_dev->id->driver_data;

	/* For now we only support one link (link context 0), driver must be
	 * reworked to break 1:1 relationship for net MBIM and to forward setup
	 * call to rmnet(QMAP) otherwise.
	 */
	if (if_id != 0)
		return -EINVAL;

	if (dev_get_drvdata(&mhi_dev->dev))
		return -EBUSY;

	mhi_netdev = wwan_netdev_drvpriv(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->proto = info->proto;

	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);

	if (extack)
		err = register_netdevice(ndev);
	else
		err = register_netdev(ndev);
	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_netdevice(ndev);
out_err:
	free_netdev(ndev);
	return err;
}

static void mhi_net_dellink(void *ctxt, struct net_device *ndev,
			    struct list_head *head)
{
	struct mhi_net_dev *mhi_netdev = wwan_netdev_drvpriv(ndev);
	struct mhi_device *mhi_dev = ctxt;

	if (head)
		unregister_netdevice_queue(ndev, head);
	else
		unregister_netdev(ndev);

	mhi_unprepare_from_transfer(mhi_dev);

	kfree_skb(mhi_netdev->skbagg_head);

	dev_set_drvdata(&mhi_dev->dev, NULL);
}

static const struct wwan_ops mhi_wwan_ops = {
	.priv_size = sizeof(struct mhi_net_dev),
	.setup = mhi_net_setup,
	.newlink = mhi_net_newlink,
	.dellink = mhi_net_dellink,
};

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 mhi_controller *cntrl = mhi_dev->mhi_cntrl;
	struct net_device *ndev;
	int err;

	err = wwan_register_ops(&cntrl->mhi_dev->dev, &mhi_wwan_ops, mhi_dev,
				WWAN_NO_DEFAULT_LINK);
	if (err)
		return err;

	if (!create_default_iface)
		return 0;

	/* Create a default interface which is used as either RMNET real-dev,
	 * MBIM link 0 or ip link 0)
	 */
	ndev = alloc_netdev(sizeof(struct mhi_net_dev), info->netname,
			    NET_NAME_PREDICTABLE, mhi_net_setup);
	if (!ndev) {
		err = -ENOMEM;
		goto err_unregister;
	}

	SET_NETDEV_DEV(ndev, &mhi_dev->dev);

	err = mhi_net_newlink(mhi_dev, ndev, 0, NULL);
	if (err)
		goto err_release;

	return 0;

err_release:
	free_netdev(ndev);
err_unregister:
	wwan_unregister_ops(&cntrl->mhi_dev->dev);

	return err;
}

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

	/* WWAN core takes care of removing remaining links */
	wwan_unregister_ops(&cntrl->mhi_dev->dev);

	if (create_default_iface)
		mhi_net_dellink(mhi_dev, mhi_netdev->ndev, NULL);
}

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_info mhi_hwip0_mbim = {
	.netname = "mhi_mbim%d",
	.proto = &proto_mbim,
};

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 },
	/* Hardware accelerated data PATH (to modem IPA), MBIM protocol */
	{ .chan = "IP_HW0_MBIM", .driver_data = (kernel_ulong_t)&mhi_hwip0_mbim },
	{}
};
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");
Commit	Line	Data
3ffec6a1 LP	1	// SPDX-License-Identifier: GPL-2.0-or-later
	2	/* MHI Network driver - Network over MHI bus
	3	*
	4	* Copyright (C) 2020 Linaro Ltd <loic.poulain@linaro.org>
	5	*/
	6
	7	#include <linux/if_arp.h>
	8	#include <linux/mhi.h>
	9	#include <linux/mod_devicetable.h>
	10	#include <linux/module.h>
	11	#include <linux/netdevice.h>
	12	#include <linux/skbuff.h>
	13	#include <linux/u64_stats_sync.h>
13adac03	14	#include <linux/wwan.h>
3ffec6a1	15
77e8080e LP	16	#include "mhi.h"
77e8080e LP	17
3ffec6a1 LP	18	#define MHI_NET_MIN_MTU ETH_MIN_MTU
	19	#define MHI_NET_MAX_MTU 0xffff
	20	#define MHI_NET_DEFAULT_MTU 0x4000
	21
13adac03 LP	22	/* When set to false, the default netdev (link 0) is not created, and it's up
	23	* to user to create the link (via wwan rtnetlink).
	24	*/
	25	static bool create_default_iface = true;
	26	module_param(create_default_iface, bool, 0);
	27
ddeb9bfa LP	28	struct mhi_device_info {
	29	const char *netname;
	30	const struct mhi_net_proto *proto;
	31	};
	32
3ffec6a1 LP	33	static int mhi_ndo_open(struct net_device *ndev)
3ffec6a1 LP	34	{
69940924	35	struct mhi_net_dev *mhi_netdev = wwan_netdev_drvpriv(ndev);
3ffec6a1 LP	36
	37	/* Feed the rx buffer pool */
	38	schedule_delayed_work(&mhi_netdev->rx_refill, 0);
	39
	40	/* Carrier is established via out-of-band channel (e.g. qmi) */
	41	netif_carrier_on(ndev);
	42
	43	netif_start_queue(ndev);
	44
	45	return 0;
	46	}
	47
	48	static int mhi_ndo_stop(struct net_device *ndev)
	49	{
69940924	50	struct mhi_net_dev *mhi_netdev = wwan_netdev_drvpriv(ndev);
3ffec6a1 LP	51
	52	netif_stop_queue(ndev);
	53	netif_carrier_off(ndev);
	54	cancel_delayed_work_sync(&mhi_netdev->rx_refill);
	55
	56	return 0;
	57	}
	58
2214fb53	59	static netdev_tx_t mhi_ndo_xmit(struct sk_buff skb, struct net_device ndev)
3ffec6a1	60	{
69940924	61	struct mhi_net_dev *mhi_netdev = wwan_netdev_drvpriv(ndev);
ddeb9bfa	62	const struct mhi_net_proto *proto = mhi_netdev->proto;
3ffec6a1 LP	63	struct mhi_device *mdev = mhi_netdev->mdev;
	64	int err;
	65
ddeb9bfa LP	66	if (proto && proto->tx_fixup) {
	67	skb = proto->tx_fixup(mhi_netdev, skb);
	68	if (unlikely(!skb))
	69	goto exit_drop;
	70	}
	71
3ffec6a1 LP	72	err = mhi_queue_skb(mdev, DMA_TO_DEVICE, skb, skb->len, MHI_EOT);
	73	if (unlikely(err)) {
	74	net_err_ratelimited("%s: Failed to queue TX buf (%d)\n",
	75	ndev->name, err);
3ffec6a1	76	dev_kfree_skb_any(skb);
ddeb9bfa	77	goto exit_drop;
3ffec6a1 LP	78	}
	79
	80	if (mhi_queue_is_full(mdev, DMA_TO_DEVICE))
	81	netif_stop_queue(ndev);
	82
	83	return NETDEV_TX_OK;
ddeb9bfa LP	84
	85	exit_drop:
	86	u64_stats_update_begin(&mhi_netdev->stats.tx_syncp);
	87	u64_stats_inc(&mhi_netdev->stats.tx_dropped);
	88	u64_stats_update_end(&mhi_netdev->stats.tx_syncp);
	89
	90	return NETDEV_TX_OK;
3ffec6a1 LP	91	}
	92
	93	static void mhi_ndo_get_stats64(struct net_device *ndev,
	94	struct rtnl_link_stats64 *stats)
	95	{
69940924	96	struct mhi_net_dev *mhi_netdev = wwan_netdev_drvpriv(ndev);
3ffec6a1 LP	97	unsigned int start;
	98
	99	do {
	100	start = u64_stats_fetch_begin_irq(&mhi_netdev->stats.rx_syncp);
	101	stats->rx_packets = u64_stats_read(&mhi_netdev->stats.rx_packets);
	102	stats->rx_bytes = u64_stats_read(&mhi_netdev->stats.rx_bytes);
	103	stats->rx_errors = u64_stats_read(&mhi_netdev->stats.rx_errors);
	104	stats->rx_dropped = u64_stats_read(&mhi_netdev->stats.rx_dropped);
84c55f16	105	stats->rx_length_errors = u64_stats_read(&mhi_netdev->stats.rx_length_errors);
3ffec6a1 LP	106	} while (u64_stats_fetch_retry_irq(&mhi_netdev->stats.rx_syncp, start));
	107
	108	do {
	109	start = u64_stats_fetch_begin_irq(&mhi_netdev->stats.tx_syncp);
	110	stats->tx_packets = u64_stats_read(&mhi_netdev->stats.tx_packets);
	111	stats->tx_bytes = u64_stats_read(&mhi_netdev->stats.tx_bytes);
	112	stats->tx_errors = u64_stats_read(&mhi_netdev->stats.tx_errors);
	113	stats->tx_dropped = u64_stats_read(&mhi_netdev->stats.tx_dropped);
	114	} while (u64_stats_fetch_retry_irq(&mhi_netdev->stats.tx_syncp, start));
	115	}
	116
	117	static const struct net_device_ops mhi_netdev_ops = {
	118	.ndo_open = mhi_ndo_open,
	119	.ndo_stop = mhi_ndo_stop,
	120	.ndo_start_xmit = mhi_ndo_xmit,
	121	.ndo_get_stats64 = mhi_ndo_get_stats64,
	122	};
	123
	124	static void mhi_net_setup(struct net_device *ndev)
	125	{
	126	ndev->header_ops = NULL; /* No header */
c134db89	127	ndev->type = ARPHRD_RAWIP;
3ffec6a1 LP	128	ndev->hard_header_len = 0;
	129	ndev->addr_len = 0;
	130	ndev->flags = IFF_POINTOPOINT \| IFF_NOARP;
	131	ndev->netdev_ops = &mhi_netdev_ops;
	132	ndev->mtu = MHI_NET_DEFAULT_MTU;
	133	ndev->min_mtu = MHI_NET_MIN_MTU;
	134	ndev->max_mtu = MHI_NET_MAX_MTU;
	135	ndev->tx_queue_len = 1000;
	136	}
	137
c1fcda2b LP	138	static struct sk_buff mhi_net_skb_agg(struct mhi_net_dev mhi_netdev,
	139	struct sk_buff *skb)
	140	{
	141	struct sk_buff *head = mhi_netdev->skbagg_head;
	142	struct sk_buff *tail = mhi_netdev->skbagg_tail;
	143
	144	/* This is non-paged skb chaining using frag_list */
	145	if (!head) {
	146	mhi_netdev->skbagg_head = skb;
	147	return skb;
	148	}
	149
	150	if (!skb_shinfo(head)->frag_list)
	151	skb_shinfo(head)->frag_list = skb;
	152	else
	153	tail->next = skb;
	154
	155	head->len += skb->len;
	156	head->data_len += skb->len;
	157	head->truesize += skb->truesize;
	158
	159	mhi_netdev->skbagg_tail = skb;
	160
	161	return mhi_netdev->skbagg_head;
	162	}
	163
3ffec6a1 LP	164	static void mhi_net_dl_callback(struct mhi_device *mhi_dev,
	165	struct mhi_result *mhi_res)
	166	{
	167	struct mhi_net_dev *mhi_netdev = dev_get_drvdata(&mhi_dev->dev);
ddeb9bfa	168	const struct mhi_net_proto *proto = mhi_netdev->proto;
3ffec6a1	169	struct sk_buff *skb = mhi_res->buf_addr;
6e10785e	170	int free_desc_count;
3ffec6a1	171
6e10785e	172	free_desc_count = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE);
3ffec6a1 LP	173
3ffec6a1 LP	174	if (unlikely(mhi_res->transaction_status)) {
c1fcda2b LP	175	switch (mhi_res->transaction_status) {
	176	case -EOVERFLOW:
	177	/* Packet can not fit in one MHI buffer and has been
	178	* split over multiple MHI transfers, do re-aggregation.
	179	* That usually means the device side MTU is larger than
	180	* the host side MTU/MRU. Since this is not optimal,
	181	* print a warning (once).
	182	*/
	183	netdev_warn_once(mhi_netdev->ndev,
	184	"Fragmented packets received, fix MTU?\n");
	185	skb_put(skb, mhi_res->bytes_xferd);
	186	mhi_net_skb_agg(mhi_netdev, skb);
	187	break;
	188	case -ENOTCONN:
	189	/* MHI layer stopping/resetting the DL channel */
	190	dev_kfree_skb_any(skb);
3ffec6a1	191	return;
c1fcda2b LP	192	default:
	193	/* Unknown error, simply drop */
	194	dev_kfree_skb_any(skb);
	195	u64_stats_update_begin(&mhi_netdev->stats.rx_syncp);
	196	u64_stats_inc(&mhi_netdev->stats.rx_errors);
	197	u64_stats_update_end(&mhi_netdev->stats.rx_syncp);
	198	}
3ffec6a1	199	} else {
c1fcda2b LP	200	skb_put(skb, mhi_res->bytes_xferd);
	201
	202	if (mhi_netdev->skbagg_head) {
	203	/* Aggregate the final fragment */
	204	skb = mhi_net_skb_agg(mhi_netdev, skb);
	205	mhi_netdev->skbagg_head = NULL;
	206	}
	207
3ffec6a1 LP	208	u64_stats_update_begin(&mhi_netdev->stats.rx_syncp);
3ffec6a1 LP	209	u64_stats_inc(&mhi_netdev->stats.rx_packets);
c1fcda2b	210	u64_stats_add(&mhi_netdev->stats.rx_bytes, skb->len);
3ffec6a1 LP	211	u64_stats_update_end(&mhi_netdev->stats.rx_syncp);
3ffec6a1 LP	212
c134db89 LP	213	switch (skb->data[0] & 0xf0) {
	214	case 0x40:
	215	skb->protocol = htons(ETH_P_IP);
	216	break;
	217	case 0x60:
	218	skb->protocol = htons(ETH_P_IPV6);
	219	break;
	220	default:
	221	skb->protocol = htons(ETH_P_MAP);
	222	break;
	223	}
	224
ddeb9bfa LP	225	if (proto && proto->rx)
	226	proto->rx(mhi_netdev, skb);
	227	else
	228	netif_rx(skb);
3ffec6a1 LP	229	}
	230
	231	/* Refill if RX buffers queue becomes low */
6e10785e	232	if (free_desc_count >= mhi_netdev->rx_queue_sz / 2)
3ffec6a1 LP	233	schedule_delayed_work(&mhi_netdev->rx_refill, 0);
	234	}
	235
	236	static void mhi_net_ul_callback(struct mhi_device *mhi_dev,
	237	struct mhi_result *mhi_res)
	238	{
	239	struct mhi_net_dev *mhi_netdev = dev_get_drvdata(&mhi_dev->dev);
	240	struct net_device *ndev = mhi_netdev->ndev;
efc36d3c	241	struct mhi_device *mdev = mhi_netdev->mdev;
3ffec6a1 LP	242	struct sk_buff *skb = mhi_res->buf_addr;
	243
	244	/* Hardware has consumed the buffer, so free the skb (which is not
	245	* freed by the MHI stack) and perform accounting.
	246	*/
	247	dev_consume_skb_any(skb);
	248
	249	u64_stats_update_begin(&mhi_netdev->stats.tx_syncp);
	250	if (unlikely(mhi_res->transaction_status)) {
	251
	252	/* MHI layer stopping/resetting the UL channel */
	253	if (mhi_res->transaction_status == -ENOTCONN) {
	254	u64_stats_update_end(&mhi_netdev->stats.tx_syncp);
	255	return;
	256	}
	257
	258	u64_stats_inc(&mhi_netdev->stats.tx_errors);
	259	} else {
	260	u64_stats_inc(&mhi_netdev->stats.tx_packets);
	261	u64_stats_add(&mhi_netdev->stats.tx_bytes, mhi_res->bytes_xferd);
	262	}
	263	u64_stats_update_end(&mhi_netdev->stats.tx_syncp);
	264
efc36d3c	265	if (netif_queue_stopped(ndev) && !mhi_queue_is_full(mdev, DMA_TO_DEVICE))
3ffec6a1 LP	266	netif_wake_queue(ndev);
	267	}
	268
	269	static void mhi_net_rx_refill_work(struct work_struct *work)
	270	{
	271	struct mhi_net_dev *mhi_netdev = container_of(work, struct mhi_net_dev,
	272	rx_refill.work);
	273	struct net_device *ndev = mhi_netdev->ndev;
	274	struct mhi_device *mdev = mhi_netdev->mdev;
3ffec6a1	275	struct sk_buff *skb;
3af562a3	276	unsigned int size;
3ffec6a1 LP	277	int err;
3ffec6a1 LP	278
3af562a3 LP	279	size = mhi_netdev->mru ? mhi_netdev->mru : READ_ONCE(ndev->mtu);
3af562a3 LP	280
6e10785e	281	while (!mhi_queue_is_full(mdev, DMA_FROM_DEVICE)) {
3ffec6a1 LP	282	skb = netdev_alloc_skb(ndev, size);
	283	if (unlikely(!skb))
	284	break;
	285
	286	err = mhi_queue_skb(mdev, DMA_FROM_DEVICE, skb, size, MHI_EOT);
	287	if (unlikely(err)) {
	288	net_err_ratelimited("%s: Failed to queue RX buf (%d)\n",
	289	ndev->name, err);
	290	kfree_skb(skb);
	291	break;
	292	}
	293
3ffec6a1 LP	294	/* Do not hog the CPU if rx buffers are consumed faster than
	295	* queued (unlikely).
	296	*/
	297	cond_resched();
	298	}
	299
	300	/* If we're still starved of rx buffers, reschedule later */
6e10785e	301	if (mhi_get_free_desc_count(mdev, DMA_FROM_DEVICE) == mhi_netdev->rx_queue_sz)
3ffec6a1 LP	302	schedule_delayed_work(&mhi_netdev->rx_refill, HZ / 2);
	303	}
	304
13adac03 LP	305	static int mhi_net_newlink(void ctxt, struct net_device ndev, u32 if_id,
13adac03 LP	306	struct netlink_ext_ack *extack)
3ffec6a1	307	{
13adac03 LP	308	const struct mhi_device_info *info;
13adac03 LP	309	struct mhi_device *mhi_dev = ctxt;
3ffec6a1	310	struct mhi_net_dev *mhi_netdev;
3ffec6a1 LP	311	int err;
3ffec6a1 LP	312
13adac03 LP	313	info = (struct mhi_device_info *)mhi_dev->id->driver_data;
	314
	315	/* For now we only support one link (link context 0), driver must be
	316	* reworked to break 1:1 relationship for net MBIM and to forward setup
	317	* call to rmnet(QMAP) otherwise.
	318	*/
	319	if (if_id != 0)
	320	return -EINVAL;
	321
	322	if (dev_get_drvdata(&mhi_dev->dev))
	323	return -EBUSY;
3ffec6a1	324
69940924	325	mhi_netdev = wwan_netdev_drvpriv(ndev);
13adac03 LP	326
13adac03 LP	327	dev_set_drvdata(&mhi_dev->dev, mhi_netdev);
3ffec6a1 LP	328	mhi_netdev->ndev = ndev;
3ffec6a1 LP	329	mhi_netdev->mdev = mhi_dev;
c1fcda2b	330	mhi_netdev->skbagg_head = NULL;
ddeb9bfa	331	mhi_netdev->proto = info->proto;
3ffec6a1	332
3ffec6a1 LP	333	INIT_DELAYED_WORK(&mhi_netdev->rx_refill, mhi_net_rx_refill_work);
	334	u64_stats_init(&mhi_netdev->stats.rx_syncp);
	335	u64_stats_init(&mhi_netdev->stats.tx_syncp);
	336
	337	/* Start MHI channels */
	338	err = mhi_prepare_for_transfer(mhi_dev);
	339	if (err)
	340	goto out_err;
	341
e6ec3ccd LP	342	/* Number of transfer descriptors determines size of the queue */
	343	mhi_netdev->rx_queue_sz = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE);
	344
13adac03 LP	345	if (extack)
	346	err = register_netdevice(ndev);
	347	else
	348	err = register_netdev(ndev);
3ffec6a1 LP	349	if (err)
	350	goto out_err;
	351
ddeb9bfa LP	352	if (mhi_netdev->proto) {
	353	err = mhi_netdev->proto->init(mhi_netdev);
	354	if (err)
	355	goto out_err_proto;
	356	}
	357
3ffec6a1 LP	358	return 0;
3ffec6a1 LP	359
ddeb9bfa	360	out_err_proto:
13adac03	361	unregister_netdevice(ndev);
3ffec6a1 LP	362	out_err:
	363	free_netdev(ndev);
	364	return err;
	365	}
	366
13adac03 LP	367	static void mhi_net_dellink(void ctxt, struct net_device ndev,
13adac03 LP	368	struct list_head *head)
3ffec6a1	369	{
69940924	370	struct mhi_net_dev *mhi_netdev = wwan_netdev_drvpriv(ndev);
13adac03	371	struct mhi_device *mhi_dev = ctxt;
3ffec6a1	372
13adac03 LP	373	if (head)
	374	unregister_netdevice_queue(ndev, head);
	375	else
	376	unregister_netdev(ndev);
3ffec6a1	377
13adac03	378	mhi_unprepare_from_transfer(mhi_dev);
3ffec6a1	379
cda1893e	380	kfree_skb(mhi_netdev->skbagg_head);
c1fcda2b	381
13adac03 LP	382	dev_set_drvdata(&mhi_dev->dev, NULL);
	383	}
	384
1d0bbbf2	385	static const struct wwan_ops mhi_wwan_ops = {
13adac03 LP	386	.priv_size = sizeof(struct mhi_net_dev),
	387	.setup = mhi_net_setup,
	388	.newlink = mhi_net_newlink,
	389	.dellink = mhi_net_dellink,
	390	};
	391
	392	static int mhi_net_probe(struct mhi_device *mhi_dev,
	393	const struct mhi_device_id *id)
	394	{
	395	const struct mhi_device_info info = (struct mhi_device_info )id->driver_data;
	396	struct mhi_controller *cntrl = mhi_dev->mhi_cntrl;
	397	struct net_device *ndev;
	398	int err;
	399
ca374290 SR	400	err = wwan_register_ops(&cntrl->mhi_dev->dev, &mhi_wwan_ops, mhi_dev,
ca374290 SR	401	WWAN_NO_DEFAULT_LINK);
13adac03 LP	402	if (err)
	403	return err;
	404
	405	if (!create_default_iface)
	406	return 0;
	407
	408	/* Create a default interface which is used as either RMNET real-dev,
	409	* MBIM link 0 or ip link 0)
	410	*/
	411	ndev = alloc_netdev(sizeof(struct mhi_net_dev), info->netname,
	412	NET_NAME_PREDICTABLE, mhi_net_setup);
	413	if (!ndev) {
	414	err = -ENOMEM;
	415	goto err_unregister;
	416	}
	417
	418	SET_NETDEV_DEV(ndev, &mhi_dev->dev);
	419
	420	err = mhi_net_newlink(mhi_dev, ndev, 0, NULL);
	421	if (err)
	422	goto err_release;
	423
	424	return 0;
	425
	426	err_release:
	427	free_netdev(ndev);
	428	err_unregister:
	429	wwan_unregister_ops(&cntrl->mhi_dev->dev);
	430
	431	return err;
	432	}
	433
	434	static void mhi_net_remove(struct mhi_device *mhi_dev)
	435	{
	436	struct mhi_net_dev *mhi_netdev = dev_get_drvdata(&mhi_dev->dev);
	437	struct mhi_controller *cntrl = mhi_dev->mhi_cntrl;
	438
9f0248ea	439	/* WWAN core takes care of removing remaining links */
13adac03 LP	440	wwan_unregister_ops(&cntrl->mhi_dev->dev);
	441
	442	if (create_default_iface)
	443	mhi_net_dellink(mhi_dev, mhi_netdev->ndev, NULL);
3ffec6a1 LP	444	}
3ffec6a1 LP	445
ddeb9bfa LP	446	static const struct mhi_device_info mhi_hwip0 = {
	447	.netname = "mhi_hwip%d",
	448	};
	449
	450	static const struct mhi_device_info mhi_swip0 = {
	451	.netname = "mhi_swip%d",
	452	};
	453
163c5e62 LP	454	static const struct mhi_device_info mhi_hwip0_mbim = {
	455	.netname = "mhi_mbim%d",
	456	.proto = &proto_mbim,
	457	};
	458
3ffec6a1	459	static const struct mhi_device_id mhi_net_id_table[] = {
ddeb9bfa LP	460	/* Hardware accelerated data PATH (to modem IPA), protocol agnostic */
	461	{ .chan = "IP_HW0", .driver_data = (kernel_ulong_t)&mhi_hwip0 },
	462	/* Software data PATH (to modem CPU) */
	463	{ .chan = "IP_SW0", .driver_data = (kernel_ulong_t)&mhi_swip0 },
163c5e62 LP	464	/* Hardware accelerated data PATH (to modem IPA), MBIM protocol */
163c5e62 LP	465	{ .chan = "IP_HW0_MBIM", .driver_data = (kernel_ulong_t)&mhi_hwip0_mbim },
3ffec6a1 LP	466	{}
	467	};
	468	MODULE_DEVICE_TABLE(mhi, mhi_net_id_table);
	469
	470	static struct mhi_driver mhi_net_driver = {
	471	.probe = mhi_net_probe,
	472	.remove = mhi_net_remove,
	473	.dl_xfer_cb = mhi_net_dl_callback,
	474	.ul_xfer_cb = mhi_net_ul_callback,
	475	.id_table = mhi_net_id_table,
	476	.driver = {
	477	.name = "mhi_net",
	478	.owner = THIS_MODULE,
	479	},
	480	};
	481
	482	module_mhi_driver(mhi_net_driver);
	483
	484	MODULE_AUTHOR("Loic Poulain <loic.poulain@linaro.org>");
	485	MODULE_DESCRIPTION("Network over MHI");
	486	MODULE_LICENSE("GPL v2");