// SPDX-License-Identifier: GPL-2.0-only
/*      Comtrol SV11 card driver
 *
 *      This is a slightly odd Z85230 synchronous driver. All you need to
 *      know basically is
 *
 *      Its a genuine Z85230
 *
 *      It supports DMA using two DMA channels in SYNC mode. The driver doesn't
 *      use these facilities
 *
 *      The control port is at io+1, the data at io+3 and turning off the DMA
 *      is done by writing 0 to io+4
 *
 *      The hardware does the bus handling to avoid the need for delays between
 *      touching control registers.
 *
 *      Port B isn't wired (why - beats me)
 *
 *      Generic HDLC port Copyright (C) 2008 Krzysztof Halasa <khc@pm.waw.pl>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/delay.h>
#include <linux/hdlc.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <net/arp.h>

#include <asm/irq.h>
#include <asm/io.h>
#include <asm/dma.h>
#include <asm/byteorder.h>
#include "z85230.h"

static int dma;

/*      Network driver support routines
 */

static inline struct z8530_dev *dev_to_sv(struct net_device *dev)
{
        return (struct z8530_dev *)dev_to_hdlc(dev)->priv;
}

/*      Frame receive. Simple for our card as we do HDLC and there
 *      is no funny garbage involved
 */

static void hostess_input(struct z8530_channel *c, struct sk_buff *skb)
{
        /* Drop the CRC - it's not a good idea to try and negotiate it ;) */
        skb_trim(skb, skb->len - 2);
        skb->protocol = hdlc_type_trans(skb, c->netdevice);
        skb_reset_mac_header(skb);
        skb->dev = c->netdevice;
        /*      Send it to the PPP layer. We don't have time to process
         *      it right now.
         */
        netif_rx(skb);
}

/*      We've been placed in the UP state
 */

static int hostess_open(struct net_device *d)
{
        struct z8530_dev *sv11 = dev_to_sv(d);
        int err = -1;

        /*      Link layer up
         */
        switch (dma) {
        case 0:
                err = z8530_sync_open(d, &sv11->chanA);
                break;
        case 1:
                err = z8530_sync_dma_open(d, &sv11->chanA);
                break;
        case 2:
                err = z8530_sync_txdma_open(d, &sv11->chanA);
                break;
        }

        if (err)
                return err;

        err = hdlc_open(d);
        if (err) {
                switch (dma) {
                case 0:
                        z8530_sync_close(d, &sv11->chanA);
                        break;
                case 1:
                        z8530_sync_dma_close(d, &sv11->chanA);
                        break;
                case 2:
                        z8530_sync_txdma_close(d, &sv11->chanA);
                        break;
                }
                return err;
        }
        sv11->chanA.rx_function = hostess_input;

        /*
         *      Go go go
         */

        netif_start_queue(d);
        return 0;
}

static int hostess_close(struct net_device *d)
{
        struct z8530_dev *sv11 = dev_to_sv(d);
        /*      Discard new frames
         */
        sv11->chanA.rx_function = z8530_null_rx;

        hdlc_close(d);
        netif_stop_queue(d);

        switch (dma) {
        case 0:
                z8530_sync_close(d, &sv11->chanA);
                break;
        case 1:
                z8530_sync_dma_close(d, &sv11->chanA);
                break;
        case 2:
                z8530_sync_txdma_close(d, &sv11->chanA);
                break;
        }
        return 0;
}

/*      Passed network frames, fire them downwind.
 */

static netdev_tx_t hostess_queue_xmit(struct sk_buff *skb,
                                      struct net_device *d)
{
        return z8530_queue_xmit(&dev_to_sv(d)->chanA, skb);
}

static int hostess_attach(struct net_device *dev, unsigned short encoding,
                          unsigned short parity)
{
        if (encoding == ENCODING_NRZ && parity == PARITY_CRC16_PR1_CCITT)
                return 0;
        return -EINVAL;
}

/*      Description block for a Comtrol Hostess SV11 card
 */

static const struct net_device_ops hostess_ops = {
        .ndo_open       = hostess_open,
        .ndo_stop       = hostess_close,
        .ndo_start_xmit = hdlc_start_xmit,
        .ndo_siocwandev = hdlc_ioctl,
};

static struct z8530_dev *sv11_init(int iobase, int irq)
{
        struct z8530_dev *sv;
        struct net_device *netdev;
        /*      Get the needed I/O space
         */

        if (!request_region(iobase, 8, "Comtrol SV11")) {
                pr_warn("I/O 0x%X already in use\n", iobase);
                return NULL;
        }

        sv = kzalloc(sizeof(struct z8530_dev), GFP_KERNEL);
        if (!sv)
                goto err_kzalloc;

        /*      Stuff in the I/O addressing
         */

        sv->active = 0;

        sv->chanA.ctrlio = iobase + 1;
        sv->chanA.dataio = iobase + 3;
        sv->chanB.ctrlio = -1;
        sv->chanB.dataio = -1;
        sv->chanA.irqs = &z8530_nop;
        sv->chanB.irqs = &z8530_nop;

        outb(0, iobase + 4);            /* DMA off */

        /* We want a fast IRQ for this device. Actually we'd like an even faster
         * IRQ ;) - This is one driver RtLinux is made for
         */

        if (request_irq(irq, z8530_interrupt, 0,
                        "Hostess SV11", sv) < 0) {
                pr_warn("IRQ %d already in use\n", irq);
                goto err_irq;
        }

        sv->irq = irq;
        sv->chanA.private = sv;
        sv->chanA.dev = sv;
        sv->chanB.dev = sv;

        if (dma) {
                /*      You can have DMA off or 1 and 3 thats the lot
                 *      on the Comtrol.
                 */
                sv->chanA.txdma = 3;
                sv->chanA.rxdma = 1;
                outb(0x03 | 0x08, iobase + 4);          /* DMA on */
                if (request_dma(sv->chanA.txdma, "Hostess SV/11 (TX)"))
                        goto err_txdma;

                if (dma == 1)
                        if (request_dma(sv->chanA.rxdma, "Hostess SV/11 (RX)"))
                                goto err_rxdma;
        }

        /* Kill our private IRQ line the hostess can end up chattering
         * until the configuration is set
         */
        disable_irq(irq);

        /*      Begin normal initialise
         */

        if (z8530_init(sv)) {
                pr_err("Z8530 series device not found\n");
                enable_irq(irq);
                goto free_dma;
        }
        z8530_channel_load(&sv->chanB, z8530_dead_port);
        if (sv->type == Z85C30)
                z8530_channel_load(&sv->chanA, z8530_hdlc_kilostream);
        else
                z8530_channel_load(&sv->chanA, z8530_hdlc_kilostream_85230);

        enable_irq(irq);

        /*      Now we can take the IRQ
         */

        sv->chanA.netdevice = netdev = alloc_hdlcdev(sv);
        if (!netdev)
                goto free_dma;

        dev_to_hdlc(netdev)->attach = hostess_attach;
        dev_to_hdlc(netdev)->xmit = hostess_queue_xmit;
        netdev->netdev_ops = &hostess_ops;
        netdev->base_addr = iobase;
        netdev->irq = irq;

        if (register_hdlc_device(netdev)) {
                pr_err("unable to register HDLC device\n");
                free_netdev(netdev);
                goto free_dma;
        }

        z8530_describe(sv, "I/O", iobase);
        sv->active = 1;
        return sv;

free_dma:
        if (dma == 1)
                free_dma(sv->chanA.rxdma);
err_rxdma:
        if (dma)
                free_dma(sv->chanA.txdma);
err_txdma:
        free_irq(irq, sv);
err_irq:
        kfree(sv);
err_kzalloc:
        release_region(iobase, 8);
        return NULL;
}

static void sv11_shutdown(struct z8530_dev *dev)
{
        unregister_hdlc_device(dev->chanA.netdevice);
        z8530_shutdown(dev);
        free_irq(dev->irq, dev);
        if (dma) {
                if (dma == 1)
                        free_dma(dev->chanA.rxdma);
                free_dma(dev->chanA.txdma);
        }
        release_region(dev->chanA.ctrlio - 1, 8);
        free_netdev(dev->chanA.netdevice);
        kfree(dev);
}

static int io = 0x200;
static int irq = 9;

module_param_hw(io, int, ioport, 0);
MODULE_PARM_DESC(io, "The I/O base of the Comtrol Hostess SV11 card");
module_param_hw(dma, int, dma, 0);
MODULE_PARM_DESC(dma, "Set this to 1 to use DMA1/DMA3 for TX/RX");
module_param_hw(irq, int, irq, 0);
MODULE_PARM_DESC(irq, "The interrupt line setting for the Comtrol Hostess SV11 card");

MODULE_AUTHOR("Alan Cox");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Modular driver for the Comtrol Hostess SV11");

static struct z8530_dev *sv11_unit;

static int sv11_module_init(void)
{
        sv11_unit = sv11_init(io, irq);
        if (!sv11_unit)
                return -ENODEV;
        return 0;
}
module_init(sv11_module_init);

static void sv11_module_cleanup(void)
{
        if (sv11_unit)
                sv11_shutdown(sv11_unit);
}
module_exit(sv11_module_cleanup);