net: iosm: net driver

// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright (C) 2020-21 Intel Corporation.

 */

#include <linux/etherdevice.h>

#include <linux/if_arp.h>

#include <linux/if_link.h>

#include <linux/rtnetlink.h>

#include <linux/wwan.h>

#include "iosm_ipc_chnl_cfg.h"

#include "iosm_ipc_imem_ops.h"

#include "iosm_ipc_wwan.h"

#define IOSM_IP_TYPE_MASK 0xF0

#define IOSM_IP_TYPE_IPV4 0x40

#define IOSM_IP_TYPE_IPV6 0x60

#define IOSM_IF_ID_PAYLOAD 2

/**

 * struct iosm_netdev_priv - netdev private data

 * @ipc_wwan:	Pointer to iosm_wwan struct

 * @netdev:	Pointer to network interface device structure

 * @if_id:	Interface id for device.

 * @ch_id:	IPC channel number for which interface device is created.

 */

struct iosm_netdev_priv {

	struct iosm_wwan *ipc_wwan;

	struct net_device *netdev;

	int if_id;

	int ch_id;

};

/**

 * struct iosm_wwan - This structure contains information about WWAN root device

 *		      and interface to the IPC layer.

 * @ipc_imem:		Pointer to imem data-struct

 * @sub_netlist:	List of active netdevs

 * @dev:		Pointer device structure

 * @if_mutex:		Mutex used for add and remove interface id

 */

struct iosm_wwan {

	struct iosm_imem *ipc_imem;

	struct iosm_netdev_priv __rcu *sub_netlist[IP_MUX_SESSION_END + 1];

	struct device *dev;

	struct mutex if_mutex; /* Mutex used for add and remove interface id */

};

/* Bring-up the wwan net link */

static int ipc_wwan_link_open(struct net_device *netdev)

{

	struct iosm_netdev_priv *priv = netdev_priv(netdev);

	struct iosm_wwan *ipc_wwan = priv->ipc_wwan;

	int if_id = priv->if_id;

	int ret;

	if (if_id < IP_MUX_SESSION_START ||

	    if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist))

		return -EINVAL;

	mutex_lock(&ipc_wwan->if_mutex);

	/* get channel id */

	priv->ch_id = ipc_imem_sys_wwan_open(ipc_wwan->ipc_imem, if_id);

	if (priv->ch_id < 0) {

		dev_err(ipc_wwan->dev,

			"cannot connect wwan0 & id %d to the IPC mem layer",

			if_id);

		ret = -ENODEV;

		goto out;

	}

	/* enable tx path, DL data may follow */

	netif_start_queue(netdev);

	dev_dbg(ipc_wwan->dev, "Channel id %d allocated to if_id %d",

		priv->ch_id, priv->if_id);

	ret = 0;

out:

	mutex_unlock(&ipc_wwan->if_mutex);

	return ret;

}

/* Bring-down the wwan net link */

static int ipc_wwan_link_stop(struct net_device *netdev)

{

	struct iosm_netdev_priv *priv = netdev_priv(netdev);

	netif_stop_queue(netdev);

	mutex_lock(&priv->ipc_wwan->if_mutex);

	ipc_imem_sys_wwan_close(priv->ipc_wwan->ipc_imem, priv->if_id,

				priv->ch_id);

	priv->ch_id = -1;

	mutex_unlock(&priv->ipc_wwan->if_mutex);

	return 0;

}

/* Transmit a packet */

static int ipc_wwan_link_transmit(struct sk_buff *skb,

				  struct net_device *netdev)

{

	struct iosm_netdev_priv *priv = netdev_priv(netdev);

	struct iosm_wwan *ipc_wwan = priv->ipc_wwan;

	int if_id = priv->if_id;

	int ret;

	/* Interface IDs from 1 to 8 are for IP data

	 * & from 257 to 261 are for non-IP data

	 */

	if (if_id < IP_MUX_SESSION_START ||

	    if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist))

		return -EINVAL;

	/* Send the SKB to device for transmission */

	ret = ipc_imem_sys_wwan_transmit(ipc_wwan->ipc_imem,

					 if_id, priv->ch_id, skb);

	/* Return code of zero is success */

	if (ret == 0) {

		ret = NETDEV_TX_OK;

	} else if (ret == -EBUSY) {

		ret = NETDEV_TX_BUSY;

		dev_err(ipc_wwan->dev, "unable to push packets");

	} else {

		goto exit;

	}

	return ret;

exit:

	/* Log any skb drop */

	if (if_id)

		dev_dbg(ipc_wwan->dev, "skb dropped. IF_ID: %d, ret: %d", if_id,

			ret);

	dev_kfree_skb_any(skb);

	return ret;

}

/* Ops structure for wwan net link */

static const struct net_device_ops ipc_inm_ops = {

	.ndo_open = ipc_wwan_link_open,

	.ndo_stop = ipc_wwan_link_stop,

	.ndo_start_xmit = ipc_wwan_link_transmit,

};

/* Setup function for creating new net link */

static void ipc_wwan_setup(struct net_device *iosm_dev)

{

	iosm_dev->header_ops = NULL;

	iosm_dev->hard_header_len = 0;

	iosm_dev->priv_flags |= IFF_NO_QUEUE;

	iosm_dev->type = ARPHRD_NONE;

	iosm_dev->min_mtu = ETH_MIN_MTU;

	iosm_dev->max_mtu = ETH_MAX_MTU;

	iosm_dev->flags = IFF_POINTOPOINT | IFF_NOARP;

	iosm_dev->netdev_ops = &ipc_inm_ops;

}

/* Create new wwan net link */

static int ipc_wwan_newlink(void *ctxt, struct net_device *dev,

			    u32 if_id, struct netlink_ext_ack *extack)

{

	struct iosm_wwan *ipc_wwan = ctxt;

	struct iosm_netdev_priv *priv;

	int err;

	if (if_id < IP_MUX_SESSION_START ||

	    if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist))

		return -EINVAL;

	priv = netdev_priv(dev);

	priv->if_id = if_id;

	priv->netdev = dev;

	priv->ipc_wwan = ipc_wwan;

	mutex_lock(&ipc_wwan->if_mutex);

	if (rcu_access_pointer(ipc_wwan->sub_netlist[if_id])) {

		err = -EBUSY;

		goto out_unlock;

	}

	err = register_netdevice(dev);

	if (err)

		goto out_unlock;

	rcu_assign_pointer(ipc_wwan->sub_netlist[if_id], priv);

	mutex_unlock(&ipc_wwan->if_mutex);

	netif_device_attach(dev);

	return 0;

out_unlock:

	mutex_unlock(&ipc_wwan->if_mutex);

	return err;

}

static void ipc_wwan_dellink(void *ctxt, struct net_device *dev,

			     struct list_head *head)

{

	struct iosm_wwan *ipc_wwan = ctxt;

	struct iosm_netdev_priv *priv = netdev_priv(dev);

	int if_id = priv->if_id;

	if (WARN_ON(if_id < IP_MUX_SESSION_START ||

		    if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist)))

		return;

	mutex_lock(&ipc_wwan->if_mutex);

	if (WARN_ON(rcu_access_pointer(ipc_wwan->sub_netlist[if_id]) != priv))

		goto unlock;

	RCU_INIT_POINTER(ipc_wwan->sub_netlist[if_id], NULL);

	/* unregistering includes synchronize_net() */

	unregister_netdevice(dev);

unlock:

	mutex_unlock(&ipc_wwan->if_mutex);

}

static const struct wwan_ops iosm_wwan_ops = {

	.priv_size = sizeof(struct iosm_netdev_priv),

	.setup = ipc_wwan_setup,

	.newlink = ipc_wwan_newlink,

	.dellink = ipc_wwan_dellink,

};

int ipc_wwan_receive(struct iosm_wwan *ipc_wwan, struct sk_buff *skb_arg,

		     bool dss, int if_id)

{

	struct sk_buff *skb = skb_arg;

	struct net_device_stats *stats;

	struct iosm_netdev_priv *priv;

	int ret;

	if ((skb->data[0] & IOSM_IP_TYPE_MASK) == IOSM_IP_TYPE_IPV4)

		skb->protocol = htons(ETH_P_IP);

	else if ((skb->data[0] & IOSM_IP_TYPE_MASK) ==

		 IOSM_IP_TYPE_IPV6)

		skb->protocol = htons(ETH_P_IPV6);

	skb->pkt_type = PACKET_HOST;

	if (if_id < (IP_MUX_SESSION_START - 1) ||

	    if_id > (IP_MUX_SESSION_END - 1)) {

		ret = -EINVAL;

		goto free;

	}

	rcu_read_lock();

	priv = rcu_dereference(ipc_wwan->sub_netlist[if_id]);

	if (!priv) {

		ret = -EINVAL;

		goto unlock;

	}

	skb->dev = priv->netdev;

	stats = &priv->netdev->stats;

	stats->rx_packets++;

	stats->rx_bytes += skb->len;

	ret = netif_rx(skb);

	skb = NULL;

unlock:

	rcu_read_unlock();

free:

	dev_kfree_skb(skb);

	return ret;

}

void ipc_wwan_tx_flowctrl(struct iosm_wwan *ipc_wwan, int if_id, bool on)

{

	struct net_device *netdev;

	struct iosm_netdev_priv *priv;

	bool is_tx_blk;

	rcu_read_lock();

	priv = rcu_dereference(ipc_wwan->sub_netlist[if_id]);

	if (!priv) {

		rcu_read_unlock();

		return;

	}

	netdev = priv->netdev;

	is_tx_blk = netif_queue_stopped(netdev);

	if (on)

		dev_dbg(ipc_wwan->dev, "session id[%d]: flowctrl enable",

			if_id);

	if (on && !is_tx_blk)

		netif_stop_queue(netdev);

	else if (!on && is_tx_blk)

		netif_wake_queue(netdev);

	rcu_read_unlock();

}

struct iosm_wwan *ipc_wwan_init(struct iosm_imem *ipc_imem, struct device *dev)

{

	struct iosm_wwan *ipc_wwan;

	ipc_wwan = kzalloc(sizeof(*ipc_wwan), GFP_KERNEL);

	if (!ipc_wwan)

		return NULL;

	ipc_wwan->dev = dev;

	ipc_wwan->ipc_imem = ipc_imem;

	if (wwan_register_ops(ipc_wwan->dev, &iosm_wwan_ops, ipc_wwan)) {

		kfree(ipc_wwan);

		return NULL;

	}

	mutex_init(&ipc_wwan->if_mutex);

	return ipc_wwan;

}

void ipc_wwan_deinit(struct iosm_wwan *ipc_wwan)

{

	int if_id;

	wwan_unregister_ops(ipc_wwan->dev);

	for (if_id = 0; if_id < ARRAY_SIZE(ipc_wwan->sub_netlist); if_id++) {

		struct iosm_netdev_priv *priv;

		priv = rcu_access_pointer(ipc_wwan->sub_netlist[if_id]);

		if (!priv)

			continue;

		rtnl_lock();

		ipc_wwan_dellink(ipc_wwan, priv->netdev, NULL);

		rtnl_unlock();

	}

	mutex_destroy(&ipc_wwan->if_mutex);

	kfree(ipc_wwan);

}

/* SPDX-License-Identifier: GPL-2.0-only

 *

 * Copyright (C) 2020-21 Intel Corporation.

 */

#ifndef IOSM_IPC_WWAN_H

#define IOSM_IPC_WWAN_H

/**

 * ipc_wwan_init - Allocate, Init and register WWAN device

 * @ipc_imem:		Pointer to imem data-struct

 * @dev:		Pointer to device structure

 *

 * Returns: Pointer to instance on success else NULL

 */

struct iosm_wwan *ipc_wwan_init(struct iosm_imem *ipc_imem, struct device *dev);

/**

 * ipc_wwan_deinit - Unregister and free WWAN device, clear pointer

 * @ipc_wwan:	Pointer to wwan instance data

 */

void ipc_wwan_deinit(struct iosm_wwan *ipc_wwan);

/**

 * ipc_wwan_receive - Receive a downlink packet from CP.

 * @ipc_wwan:	Pointer to wwan instance

 * @skb_arg:	Pointer to struct sk_buff

 * @dss:	Set to true if interafce id is from 257 to 261,

 *		else false

 * @if_id:	Interface ID

 *

 * Return: 0 on success and failure value on error

 */

int ipc_wwan_receive(struct iosm_wwan *ipc_wwan, struct sk_buff *skb_arg,

		     bool dss, int if_id);

/**

 * ipc_wwan_tx_flowctrl - Enable/Disable TX flow control

 * @ipc_wwan:	Pointer to wwan instance

 * @id:		Ipc mux channel session id

 * @on:		if true then flow ctrl would be enabled else disable

 *

 */

void ipc_wwan_tx_flowctrl(struct iosm_wwan *ipc_wwan, int id, bool on);

/**

 * ipc_wwan_is_tx_stopped - Checks if Tx stopped for a Interface id.

 * @ipc_wwan:	Pointer to wwan instance

 * @id:		Ipc mux channel session id

 *

 * Return: true if stopped, false otherwise

 */

bool ipc_wwan_is_tx_stopped(struct iosm_wwan *ipc_wwan, int id);

#endif