// SPDX-License-Identifier: GPL-2.0
/*
 * IPWireless 3G PCMCIA Network Driver
 *
 * Original code
 *   by Stephen Blackheath <stephen@blacksapphire.com>,
 *      Ben Martel <benm@symmetric.co.nz>
 *
 * Copyrighted as follows:
 *   Copyright (C) 2004 by Symmetric Systems Ltd (NZ)
 *
 * Various driver changes and rewrites, port to new kernels
 *   Copyright (C) 2006-2007 Jiri Kosina
 *
 * Misc code cleanups and updates
 *   Copyright (C) 2007 David Sterba
 */

#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/mutex.h>
#include <linux/netdevice.h>
#include <linux/ppp_channel.h>
#include <linux/ppp_defs.h>
#include <linux/slab.h>
#include <linux/ppp-ioctl.h>
#include <linux/skbuff.h>

#include "network.h"
#include "hardware.h"
#include "main.h"
#include "tty.h"

#define MAX_ASSOCIATED_TTYS 2

#define SC_RCV_BITS     (SC_RCV_B7_1|SC_RCV_B7_0|SC_RCV_ODDP|SC_RCV_EVNP)

struct ipw_network {
        /* Hardware context, used for calls to hardware layer. */
        struct ipw_hardware *hardware;
        /* Context for kernel 'generic_ppp' functionality */
        struct ppp_channel *ppp_channel;
        /* tty context connected with IPW console */
        struct ipw_tty *associated_ttys[NO_OF_IPW_CHANNELS][MAX_ASSOCIATED_TTYS];
        /* True if ppp needs waking up once we're ready to xmit */
        int ppp_blocked;
        /* Number of packets queued up in hardware module. */
        int outgoing_packets_queued;
        /* Spinlock to avoid interrupts during shutdown */
        spinlock_t lock;
        struct mutex close_lock;

        /* PPP ioctl data, not actually used anywere */
        unsigned int flags;
        unsigned int rbits;
        u32 xaccm[8];
        u32 raccm;
        int mru;

        int shutting_down;
        unsigned int ras_control_lines;

        struct work_struct work_go_online;
        struct work_struct work_go_offline;
};

static void notify_packet_sent(void *callback_data, unsigned int packet_length)
{
        struct ipw_network *network = callback_data;
        unsigned long flags;

        spin_lock_irqsave(&network->lock, flags);
        network->outgoing_packets_queued--;
        if (network->ppp_channel != NULL) {
                if (network->ppp_blocked) {
                        network->ppp_blocked = 0;
                        spin_unlock_irqrestore(&network->lock, flags);
                        ppp_output_wakeup(network->ppp_channel);
                        if (ipwireless_debug)
                                printk(KERN_DEBUG IPWIRELESS_PCCARD_NAME
                                       ": ppp unblocked\n");
                } else
                        spin_unlock_irqrestore(&network->lock, flags);
        } else
                spin_unlock_irqrestore(&network->lock, flags);
}

/*
 * Called by the ppp system when it has a packet to send to the hardware.
 */
static int ipwireless_ppp_start_xmit(struct ppp_channel *ppp_channel,
                                     struct sk_buff *skb)
{
        struct ipw_network *network = ppp_channel->private;
        unsigned long flags;

        spin_lock_irqsave(&network->lock, flags);
        if (network->outgoing_packets_queued < ipwireless_out_queue) {
                unsigned char *buf;
                static unsigned char header[] = {
                        PPP_ALLSTATIONS, /* 0xff */
                        PPP_UI,          /* 0x03 */
                };
                int ret;

                network->outgoing_packets_queued++;
                spin_unlock_irqrestore(&network->lock, flags);

                /*
                 * If we have the requested amount of headroom in the skb we
                 * were handed, then we can add the header efficiently.
                 */
                if (skb_headroom(skb) >= 2) {
                        memcpy(skb_push(skb, 2), header, 2);
                        ret = ipwireless_send_packet(network->hardware,
                                               IPW_CHANNEL_RAS, skb->data,
                                               skb->len,
                                               notify_packet_sent,
                                               network);
                        if (ret < 0) {
                                skb_pull(skb, 2);
                                return 0;
                        }
                } else {
                        /* Otherwise (rarely) we do it inefficiently. */
                        buf = kmalloc(skb->len + 2, GFP_ATOMIC);
                        if (!buf)
                                return 0;
                        memcpy(buf + 2, skb->data, skb->len);
                        memcpy(buf, header, 2);
                        ret = ipwireless_send_packet(network->hardware,
                                               IPW_CHANNEL_RAS, buf,
                                               skb->len + 2,
                                               notify_packet_sent,
                                               network);
                        kfree(buf);
                        if (ret < 0)
                                return 0;
                }
                kfree_skb(skb);
                return 1;
        } else {
                /*
                 * Otherwise reject the packet, and flag that the ppp system
                 * needs to be unblocked once we are ready to send.
                 */
                network->ppp_blocked = 1;
                spin_unlock_irqrestore(&network->lock, flags);
                if (ipwireless_debug)
                        printk(KERN_DEBUG IPWIRELESS_PCCARD_NAME ": ppp blocked\n");
                return 0;
        }
}

/* Handle an ioctl call that has come in via ppp. (copy of ppp_async_ioctl() */
static int ipwireless_ppp_ioctl(struct ppp_channel *ppp_channel,
                                unsigned int cmd, unsigned long arg)
{
        struct ipw_network *network = ppp_channel->private;
        int err, val;
        u32 accm[8];
        int __user *user_arg = (int __user *) arg;

        err = -EFAULT;
        switch (cmd) {
        case PPPIOCGFLAGS:
                val = network->flags | network->rbits;
                if (put_user(val, user_arg))
                        break;
                err = 0;
                break;

        case PPPIOCSFLAGS:
                if (get_user(val, user_arg))
                        break;
                network->flags = val & ~SC_RCV_BITS;
                network->rbits = val & SC_RCV_BITS;
                err = 0;
                break;

        case PPPIOCGASYNCMAP:
                if (put_user(network->xaccm[0], user_arg))
                        break;
                err = 0;
                break;

        case PPPIOCSASYNCMAP:
                if (get_user(network->xaccm[0], user_arg))
                        break;
                err = 0;
                break;

        case PPPIOCGRASYNCMAP:
                if (put_user(network->raccm, user_arg))
                        break;
                err = 0;
                break;

        case PPPIOCSRASYNCMAP:
                if (get_user(network->raccm, user_arg))
                        break;
                err = 0;
                break;

        case PPPIOCGXASYNCMAP:
                if (copy_to_user((void __user *) arg, network->xaccm,
                                        sizeof(network->xaccm)))
                        break;
                err = 0;
                break;

        case PPPIOCSXASYNCMAP:
                if (copy_from_user(accm, (void __user *) arg, sizeof(accm)))
                        break;
                accm[2] &= ~0x40000000U;        /* can't escape 0x5e */
                accm[3] |= 0x60000000U; /* must escape 0x7d, 0x7e */
                memcpy(network->xaccm, accm, sizeof(network->xaccm));
                err = 0;
                break;

        case PPPIOCGMRU:
                if (put_user(network->mru, user_arg))
                        break;
                err = 0;
                break;

        case PPPIOCSMRU:
                if (get_user(val, user_arg))
                        break;
                if (val < PPP_MRU)
                        val = PPP_MRU;
                network->mru = val;
                err = 0;
                break;

        default:
                err = -ENOTTY;
        }

        return err;
}

static const struct ppp_channel_ops ipwireless_ppp_channel_ops = {
        .start_xmit = ipwireless_ppp_start_xmit,
        .ioctl      = ipwireless_ppp_ioctl
};

static void do_go_online(struct work_struct *work_go_online)
{
        struct ipw_network *network =
                container_of(work_go_online, struct ipw_network,
                                work_go_online);
        unsigned long flags;

        spin_lock_irqsave(&network->lock, flags);
        if (!network->ppp_channel) {
                struct ppp_channel *channel;

                spin_unlock_irqrestore(&network->lock, flags);
                channel = kzalloc_obj(struct ppp_channel);
                if (!channel) {
                        printk(KERN_ERR IPWIRELESS_PCCARD_NAME
                                        ": unable to allocate PPP channel\n");
                        return;
                }
                channel->private = network;
                channel->mtu = 16384;   /* Wild guess */
                channel->hdrlen = 2;
                channel->ops = &ipwireless_ppp_channel_ops;

                network->flags = 0;
                network->rbits = 0;
                network->mru = PPP_MRU;
                memset(network->xaccm, 0, sizeof(network->xaccm));
                network->xaccm[0] = ~0U;
                network->xaccm[3] = 0x60000000U;
                network->raccm = ~0U;
                if (ppp_register_channel(channel) < 0) {
                        printk(KERN_ERR IPWIRELESS_PCCARD_NAME
                                        ": unable to register PPP channel\n");
                        kfree(channel);
                        return;
                }
                spin_lock_irqsave(&network->lock, flags);
                network->ppp_channel = channel;
        }
        spin_unlock_irqrestore(&network->lock, flags);
}

static void do_go_offline(struct work_struct *work_go_offline)
{
        struct ipw_network *network =
                container_of(work_go_offline, struct ipw_network,
                                work_go_offline);
        unsigned long flags;

        mutex_lock(&network->close_lock);
        spin_lock_irqsave(&network->lock, flags);
        if (network->ppp_channel != NULL) {
                struct ppp_channel *channel = network->ppp_channel;

                network->ppp_channel = NULL;
                spin_unlock_irqrestore(&network->lock, flags);
                mutex_unlock(&network->close_lock);
                ppp_unregister_channel(channel);
        } else {
                spin_unlock_irqrestore(&network->lock, flags);
                mutex_unlock(&network->close_lock);
        }
}

void ipwireless_network_notify_control_line_change(struct ipw_network *network,
                                                   unsigned int channel_idx,
                                                   unsigned int control_lines,
                                                   unsigned int changed_mask)
{
        int i;

        if (channel_idx == IPW_CHANNEL_RAS)
                network->ras_control_lines = control_lines;

        for (i = 0; i < MAX_ASSOCIATED_TTYS; i++) {
                struct ipw_tty *tty =
                        network->associated_ttys[channel_idx][i];

                /*
                 * If it's associated with a tty (other than the RAS channel
                 * when we're online), then send the data to that tty.  The RAS
                 * channel's data is handled above - it always goes through
                 * ppp_generic.
                 */
                if (tty)
                        ipwireless_tty_notify_control_line_change(tty,
                                                                  channel_idx,
                                                                  control_lines,
                                                                  changed_mask);
        }
}

/*
 * Some versions of firmware stuff packets with 0xff 0x03 (PPP: ALLSTATIONS, UI)
 * bytes, which are required on sent packet, but not always present on received
 * packets
 */
static struct sk_buff *ipw_packet_received_skb(unsigned char *data,
                                               unsigned int length)
{
        struct sk_buff *skb;

        if (length > 2 && data[0] == PPP_ALLSTATIONS && data[1] == PPP_UI) {
                length -= 2;
                data += 2;
        }

        skb = dev_alloc_skb(length + 4);
        if (skb == NULL)
                return NULL;
        skb_reserve(skb, 2);
        skb_put_data(skb, data, length);

        return skb;
}

void ipwireless_network_packet_received(struct ipw_network *network,
                                        unsigned int channel_idx,
                                        unsigned char *data,
                                        unsigned int length)
{
        int i;
        unsigned long flags;

        for (i = 0; i < MAX_ASSOCIATED_TTYS; i++) {
                struct ipw_tty *tty = network->associated_ttys[channel_idx][i];

                if (!tty)
                        continue;

                /*
                 * If it's associated with a tty (other than the RAS channel
                 * when we're online), then send the data to that tty.  The RAS
                 * channel's data is handled above - it always goes through
                 * ppp_generic.
                 */
                if (channel_idx == IPW_CHANNEL_RAS
                                && (network->ras_control_lines &
                                        IPW_CONTROL_LINE_DCD) != 0
                                && ipwireless_tty_is_modem(tty)) {
                        /*
                         * If data came in on the RAS channel and this tty is
                         * the modem tty, and we are online, then we send it to
                         * the PPP layer.
                         */
                        mutex_lock(&network->close_lock);
                        spin_lock_irqsave(&network->lock, flags);
                        if (network->ppp_channel != NULL) {
                                struct sk_buff *skb;

                                spin_unlock_irqrestore(&network->lock,
                                                flags);

                                /* Send the data to the ppp_generic module. */
                                skb = ipw_packet_received_skb(data, length);
                                if (skb)
                                        ppp_input(network->ppp_channel, skb);
                        } else
                                spin_unlock_irqrestore(&network->lock,
                                                flags);
                        mutex_unlock(&network->close_lock);
                }
                /* Otherwise we send it out the tty. */
                else
                        ipwireless_tty_received(tty, data, length);
        }
}

struct ipw_network *ipwireless_network_create(struct ipw_hardware *hw)
{
        struct ipw_network *network =
                kzalloc_obj(struct ipw_network);

        if (!network)
                return NULL;

        spin_lock_init(&network->lock);
        mutex_init(&network->close_lock);

        network->hardware = hw;

        INIT_WORK(&network->work_go_online, do_go_online);
        INIT_WORK(&network->work_go_offline, do_go_offline);

        ipwireless_associate_network(hw, network);

        return network;
}

void ipwireless_network_free(struct ipw_network *network)
{
        network->shutting_down = 1;

        ipwireless_ppp_close(network);
        flush_work(&network->work_go_online);
        flush_work(&network->work_go_offline);

        ipwireless_stop_interrupts(network->hardware);
        ipwireless_associate_network(network->hardware, NULL);

        kfree(network);
}

void ipwireless_associate_network_tty(struct ipw_network *network,
                                      unsigned int channel_idx,
                                      struct ipw_tty *tty)
{
        int i;

        for (i = 0; i < MAX_ASSOCIATED_TTYS; i++)
                if (network->associated_ttys[channel_idx][i] == NULL) {
                        network->associated_ttys[channel_idx][i] = tty;
                        break;
                }
}

void ipwireless_disassociate_network_ttys(struct ipw_network *network,
                                          unsigned int channel_idx)
{
        int i;

        for (i = 0; i < MAX_ASSOCIATED_TTYS; i++)
                network->associated_ttys[channel_idx][i] = NULL;
}

void ipwireless_ppp_open(struct ipw_network *network)
{
        if (ipwireless_debug)
                printk(KERN_DEBUG IPWIRELESS_PCCARD_NAME ": online\n");
        schedule_work(&network->work_go_online);
}

void ipwireless_ppp_close(struct ipw_network *network)
{
        /* Disconnect from the wireless network. */
        if (ipwireless_debug)
                printk(KERN_DEBUG IPWIRELESS_PCCARD_NAME ": offline\n");
        schedule_work(&network->work_go_offline);
}

int ipwireless_ppp_channel_index(struct ipw_network *network)
{
        int ret = -1;
        unsigned long flags;

        spin_lock_irqsave(&network->lock, flags);
        if (network->ppp_channel != NULL)
                ret = ppp_channel_index(network->ppp_channel);
        spin_unlock_irqrestore(&network->lock, flags);

        return ret;
}

int ipwireless_ppp_unit_number(struct ipw_network *network)
{
        int ret = -1;
        unsigned long flags;

        spin_lock_irqsave(&network->lock, flags);
        if (network->ppp_channel != NULL)
                ret = ppp_unit_number(network->ppp_channel);
        spin_unlock_irqrestore(&network->lock, flags);

        return ret;
}

int ipwireless_ppp_mru(const struct ipw_network *network)
{
        return network->mru;
}