// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *      Driver for the Macintosh 68K onboard MACE controller with PSC
 *      driven DMA. The MACE driver code is derived from mace.c. The
 *      Mac68k theory of operation is courtesy of the MacBSD wizards.
 *
 *      Copyright (C) 1996 Paul Mackerras.
 *      Copyright (C) 1998 Alan Cox <alan@lxorguk.ukuu.org.uk>
 *
 *      Modified heavily by Joshua M. Thompson based on Dave Huang's NetBSD driver
 *
 *      Copyright (C) 2007 Finn Thain
 *
 *      Converted to DMA API, converted to unified driver model,
 *      sync'd some routines with mace.c and fixed various bugs.
 */


#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/delay.h>
#include <linux/string.h>
#include <linux/crc32.h>
#include <linux/bitrev.h>
#include <linux/dma-mapping.h>
#include <linux/platform_device.h>
#include <linux/gfp.h>
#include <linux/interrupt.h>
#include <asm/io.h>
#include <asm/macints.h>
#include <asm/mac_psc.h>
#include <asm/page.h>
#include "mace.h"

static char mac_mace_string[] = "macmace";

#define N_TX_BUFF_ORDER 0
#define N_TX_RING       (1 << N_TX_BUFF_ORDER)
#define N_RX_BUFF_ORDER 3
#define N_RX_RING       (1 << N_RX_BUFF_ORDER)

#define TX_TIMEOUT      HZ

#define MACE_BUFF_SIZE  0x800

/* Chip rev needs workaround on HW & multicast addr change */
#define BROKEN_ADDRCHG_REV      0x0941

/* The MACE is simply wired down on a Mac68K box */

#define MACE_BASE       (void *)(0x50F1C000)
#define MACE_PROM       (void *)(0x50F08001)

struct mace_data {
        volatile struct mace *mace;
        unsigned char *tx_ring;
        dma_addr_t tx_ring_phys;
        unsigned char *rx_ring;
        dma_addr_t rx_ring_phys;
        int dma_intr;
        int rx_slot, rx_tail;
        int tx_slot, tx_sloti, tx_count;
        int chipid;
        struct device *device;
};

struct mace_frame {
        u8      rcvcnt;
        u8      pad1;
        u8      rcvsts;
        u8      pad2;
        u8      rntpc;
        u8      pad3;
        u8      rcvcc;
        u8      pad4;
        u32     pad5;
        u32     pad6;
        DECLARE_FLEX_ARRAY(u8, data);
        /* And frame continues.. */
};

#define PRIV_BYTES      sizeof(struct mace_data)

static int mace_open(struct net_device *dev);
static int mace_close(struct net_device *dev);
static netdev_tx_t mace_xmit_start(struct sk_buff *skb, struct net_device *dev);
static void mace_set_multicast(struct net_device *dev);
static int mace_set_address(struct net_device *dev, void *addr);
static void mace_reset(struct net_device *dev);
static irqreturn_t mace_interrupt(int irq, void *dev_id);
static irqreturn_t mace_dma_intr(int irq, void *dev_id);
static void mace_tx_timeout(struct net_device *dev, unsigned int txqueue);
static void __mace_set_address(struct net_device *dev, const void *addr);

/*
 * Load a receive DMA channel with a base address and ring length
 */

static void mace_load_rxdma_base(struct net_device *dev, int set)
{
        struct mace_data *mp = netdev_priv(dev);

        psc_write_word(PSC_ENETRD_CMD + set, 0x0100);
        psc_write_long(PSC_ENETRD_ADDR + set, (u32) mp->rx_ring_phys);
        psc_write_long(PSC_ENETRD_LEN + set, N_RX_RING);
        psc_write_word(PSC_ENETRD_CMD + set, 0x9800);
        mp->rx_tail = 0;
}

/*
 * Reset the receive DMA subsystem
 */

static void mace_rxdma_reset(struct net_device *dev)
{
        struct mace_data *mp = netdev_priv(dev);
        volatile struct mace *mace = mp->mace;
        u8 maccc = mace->maccc;

        mace->maccc = maccc & ~ENRCV;

        psc_write_word(PSC_ENETRD_CTL, 0x8800);
        mace_load_rxdma_base(dev, 0x00);
        psc_write_word(PSC_ENETRD_CTL, 0x0400);

        psc_write_word(PSC_ENETRD_CTL, 0x8800);
        mace_load_rxdma_base(dev, 0x10);
        psc_write_word(PSC_ENETRD_CTL, 0x0400);

        mace->maccc = maccc;
        mp->rx_slot = 0;

        psc_write_word(PSC_ENETRD_CMD + PSC_SET0, 0x9800);
        psc_write_word(PSC_ENETRD_CMD + PSC_SET1, 0x9800);
}

/*
 * Reset the transmit DMA subsystem
 */

static void mace_txdma_reset(struct net_device *dev)
{
        struct mace_data *mp = netdev_priv(dev);
        volatile struct mace *mace = mp->mace;
        u8 maccc;

        psc_write_word(PSC_ENETWR_CTL, 0x8800);

        maccc = mace->maccc;
        mace->maccc = maccc & ~ENXMT;

        mp->tx_slot = mp->tx_sloti = 0;
        mp->tx_count = N_TX_RING;

        psc_write_word(PSC_ENETWR_CTL, 0x0400);
        mace->maccc = maccc;
}

/*
 * Disable DMA
 */

static void mace_dma_off(struct net_device *dev)
{
        psc_write_word(PSC_ENETRD_CTL, 0x8800);
        psc_write_word(PSC_ENETRD_CTL, 0x1000);
        psc_write_word(PSC_ENETRD_CMD + PSC_SET0, 0x1100);
        psc_write_word(PSC_ENETRD_CMD + PSC_SET1, 0x1100);

        psc_write_word(PSC_ENETWR_CTL, 0x8800);
        psc_write_word(PSC_ENETWR_CTL, 0x1000);
        psc_write_word(PSC_ENETWR_CMD + PSC_SET0, 0x1100);
        psc_write_word(PSC_ENETWR_CMD + PSC_SET1, 0x1100);
}

static const struct net_device_ops mace_netdev_ops = {
        .ndo_open               = mace_open,
        .ndo_stop               = mace_close,
        .ndo_start_xmit         = mace_xmit_start,
        .ndo_tx_timeout         = mace_tx_timeout,
        .ndo_set_rx_mode        = mace_set_multicast,
        .ndo_set_mac_address    = mace_set_address,
        .ndo_validate_addr      = eth_validate_addr,
};

/*
 * Not really much of a probe. The hardware table tells us if this
 * model of Macintrash has a MACE (AV macintoshes)
 */

static int mace_probe(struct platform_device *pdev)
{
        int j;
        struct mace_data *mp;
        unsigned char *addr;
        struct net_device *dev;
        unsigned char checksum = 0;
        u8 macaddr[ETH_ALEN];
        int err;

        dev = alloc_etherdev(PRIV_BYTES);
        if (!dev)
                return -ENOMEM;

        mp = netdev_priv(dev);

        mp->device = &pdev->dev;
        platform_set_drvdata(pdev, dev);
        SET_NETDEV_DEV(dev, &pdev->dev);

        dev->base_addr = (u32)MACE_BASE;
        mp->mace = MACE_BASE;

        dev->irq = IRQ_MAC_MACE;
        mp->dma_intr = IRQ_MAC_MACE_DMA;

        mp->chipid = mp->mace->chipid_hi << 8 | mp->mace->chipid_lo;

        /*
         * The PROM contains 8 bytes which total 0xFF when XOR'd
         * together. Due to the usual peculiar apple brain damage
         * the bytes are spaced out in a strange boundary and the
         * bits are reversed.
         */

        addr = MACE_PROM;

        for (j = 0; j < 6; ++j) {
                u8 v = bitrev8(addr[j<<4]);
                checksum ^= v;
                macaddr[j] = v;
        }
        eth_hw_addr_set(dev, macaddr);
        for (; j < 8; ++j) {
                checksum ^= bitrev8(addr[j<<4]);
        }

        if (checksum != 0xFF) {
                free_netdev(dev);
                return -ENODEV;
        }

        dev->netdev_ops         = &mace_netdev_ops;
        dev->watchdog_timeo     = TX_TIMEOUT;

        pr_info("Onboard MACE, hardware address %pM, chip revision 0x%04X\n",
                dev->dev_addr, mp->chipid);

        err = register_netdev(dev);
        if (!err)
                return 0;

        free_netdev(dev);
        return err;
}

/*
 * Reset the chip.
 */

static void mace_reset(struct net_device *dev)
{
        struct mace_data *mp = netdev_priv(dev);
        volatile struct mace *mb = mp->mace;
        int i;

        /* soft-reset the chip */
        i = 200;
        while (--i) {
                mb->biucc = SWRST;
                if (mb->biucc & SWRST) {
                        udelay(10);
                        continue;
                }
                break;
        }
        if (!i) {
                printk(KERN_ERR "macmace: cannot reset chip!\n");
                return;
        }

        mb->maccc = 0;  /* turn off tx, rx */
        mb->imr = 0xFF; /* disable all intrs for now */
        i = mb->ir;

        mb->biucc = XMTSP_64;
        mb->utr = RTRD;
        mb->fifocc = XMTFW_8 | RCVFW_64 | XMTFWU | RCVFWU;

        mb->xmtfc = AUTO_PAD_XMIT; /* auto-pad short frames */
        mb->rcvfc = 0;

        /* load up the hardware address */
        __mace_set_address(dev, dev->dev_addr);

        /* clear the multicast filter */
        if (mp->chipid == BROKEN_ADDRCHG_REV)
                mb->iac = LOGADDR;
        else {
                mb->iac = ADDRCHG | LOGADDR;
                while ((mb->iac & ADDRCHG) != 0)
                        ;
        }
        for (i = 0; i < 8; ++i)
                mb->ladrf = 0;

        /* done changing address */
        if (mp->chipid != BROKEN_ADDRCHG_REV)
                mb->iac = 0;

        mb->plscc = PORTSEL_AUI;
}

/*
 * Load the address on a mace controller.
 */

static void __mace_set_address(struct net_device *dev, const void *addr)
{
        struct mace_data *mp = netdev_priv(dev);
        volatile struct mace *mb = mp->mace;
        const unsigned char *p = addr;
        u8 macaddr[ETH_ALEN];
        int i;

        /* load up the hardware address */
        if (mp->chipid == BROKEN_ADDRCHG_REV)
                mb->iac = PHYADDR;
        else {
                mb->iac = ADDRCHG | PHYADDR;
                while ((mb->iac & ADDRCHG) != 0)
                        ;
        }
        for (i = 0; i < 6; ++i)
                mb->padr = macaddr[i] = p[i];
        eth_hw_addr_set(dev, macaddr);
        if (mp->chipid != BROKEN_ADDRCHG_REV)
                mb->iac = 0;
}

static int mace_set_address(struct net_device *dev, void *addr)
{
        struct mace_data *mp = netdev_priv(dev);
        volatile struct mace *mb = mp->mace;
        unsigned long flags;
        u8 maccc;

        local_irq_save(flags);

        maccc = mb->maccc;

        __mace_set_address(dev, addr);

        mb->maccc = maccc;

        local_irq_restore(flags);

        return 0;
}

/*
 * Open the Macintosh MACE. Most of this is playing with the DMA
 * engine. The ethernet chip is quite friendly.
 */

static int mace_open(struct net_device *dev)
{
        struct mace_data *mp = netdev_priv(dev);
        volatile struct mace *mb = mp->mace;

        /* reset the chip */
        mace_reset(dev);

        if (request_irq(dev->irq, mace_interrupt, 0, dev->name, dev)) {
                printk(KERN_ERR "%s: can't get irq %d\n", dev->name, dev->irq);
                return -EAGAIN;
        }
        if (request_irq(mp->dma_intr, mace_dma_intr, 0, dev->name, dev)) {
                printk(KERN_ERR "%s: can't get irq %d\n", dev->name, mp->dma_intr);
                free_irq(dev->irq, dev);
                return -EAGAIN;
        }

        /* Allocate the DMA ring buffers */

        mp->tx_ring = dma_alloc_coherent(mp->device,
                                         N_TX_RING * MACE_BUFF_SIZE,
                                         &mp->tx_ring_phys, GFP_KERNEL);
        if (mp->tx_ring == NULL)
                goto out1;

        mp->rx_ring = dma_alloc_coherent(mp->device,
                                         N_RX_RING * MACE_BUFF_SIZE,
                                         &mp->rx_ring_phys, GFP_KERNEL);
        if (mp->rx_ring == NULL)
                goto out2;

        mace_dma_off(dev);

        /* Not sure what these do */

        psc_write_word(PSC_ENETWR_CTL, 0x9000);
        psc_write_word(PSC_ENETRD_CTL, 0x9000);
        psc_write_word(PSC_ENETWR_CTL, 0x0400);
        psc_write_word(PSC_ENETRD_CTL, 0x0400);

        mace_rxdma_reset(dev);
        mace_txdma_reset(dev);

        /* turn it on! */
        mb->maccc = ENXMT | ENRCV;
        /* enable all interrupts except receive interrupts */
        mb->imr = RCVINT;
        return 0;

out2:
        dma_free_coherent(mp->device, N_TX_RING * MACE_BUFF_SIZE,
                          mp->tx_ring, mp->tx_ring_phys);
out1:
        free_irq(dev->irq, dev);
        free_irq(mp->dma_intr, dev);
        return -ENOMEM;
}

/*
 * Shut down the mace and its interrupt channel
 */

static int mace_close(struct net_device *dev)
{
        struct mace_data *mp = netdev_priv(dev);
        volatile struct mace *mb = mp->mace;

        mb->maccc = 0;          /* disable rx and tx     */
        mb->imr = 0xFF;         /* disable all irqs      */
        mace_dma_off(dev);      /* disable rx and tx dma */

        return 0;
}

/*
 * Transmit a frame
 */

static netdev_tx_t mace_xmit_start(struct sk_buff *skb, struct net_device *dev)
{
        struct mace_data *mp = netdev_priv(dev);
        unsigned long flags;

        /* Stop the queue since there's only the one buffer */

        local_irq_save(flags);
        netif_stop_queue(dev);
        if (!mp->tx_count) {
                printk(KERN_ERR "macmace: tx queue running but no free buffers.\n");
                local_irq_restore(flags);
                return NETDEV_TX_BUSY;
        }
        mp->tx_count--;
        local_irq_restore(flags);

        dev->stats.tx_packets++;
        dev->stats.tx_bytes += skb->len;

        /* We need to copy into our xmit buffer to take care of alignment and caching issues */
        skb_copy_from_linear_data(skb, mp->tx_ring, skb->len);

        /* load the Tx DMA and fire it off */

        psc_write_long(PSC_ENETWR_ADDR + mp->tx_slot, (u32)  mp->tx_ring_phys);
        psc_write_long(PSC_ENETWR_LEN + mp->tx_slot, skb->len);
        psc_write_word(PSC_ENETWR_CMD + mp->tx_slot, 0x9800);

        mp->tx_slot ^= 0x10;

        dev_kfree_skb(skb);

        return NETDEV_TX_OK;
}

static void mace_set_multicast(struct net_device *dev)
{
        struct mace_data *mp = netdev_priv(dev);
        volatile struct mace *mb = mp->mace;
        int i;
        u32 crc;
        u8 maccc;
        unsigned long flags;

        local_irq_save(flags);
        maccc = mb->maccc;
        mb->maccc &= ~PROM;

        if (dev->flags & IFF_PROMISC) {
                mb->maccc |= PROM;
        } else {
                unsigned char multicast_filter[8];
                struct netdev_hw_addr *ha;

                if (dev->flags & IFF_ALLMULTI) {
                        for (i = 0; i < 8; i++) {
                                multicast_filter[i] = 0xFF;
                        }
                } else {
                        for (i = 0; i < 8; i++)
                                multicast_filter[i] = 0;
                        netdev_for_each_mc_addr(ha, dev) {
                                crc = ether_crc_le(6, ha->addr);
                                /* bit number in multicast_filter */
                                i = crc >> 26;
                                multicast_filter[i >> 3] |= 1 << (i & 7);
                        }
                }

                if (mp->chipid == BROKEN_ADDRCHG_REV)
                        mb->iac = LOGADDR;
                else {
                        mb->iac = ADDRCHG | LOGADDR;
                        while ((mb->iac & ADDRCHG) != 0)
                                ;
                }
                for (i = 0; i < 8; ++i)
                        mb->ladrf = multicast_filter[i];
                if (mp->chipid != BROKEN_ADDRCHG_REV)
                        mb->iac = 0;
        }

        mb->maccc = maccc;
        local_irq_restore(flags);
}

static void mace_handle_misc_intrs(struct net_device *dev, int intr)
{
        struct mace_data *mp = netdev_priv(dev);
        volatile struct mace *mb = mp->mace;
        static int mace_babbles, mace_jabbers;

        if (intr & MPCO)
                dev->stats.rx_missed_errors += 256;
        dev->stats.rx_missed_errors += mb->mpc;   /* reading clears it */
        if (intr & RNTPCO)
                dev->stats.rx_length_errors += 256;
        dev->stats.rx_length_errors += mb->rntpc; /* reading clears it */
        if (intr & CERR)
                ++dev->stats.tx_heartbeat_errors;
        if (intr & BABBLE)
                if (mace_babbles++ < 4)
                        printk(KERN_DEBUG "macmace: babbling transmitter\n");
        if (intr & JABBER)
                if (mace_jabbers++ < 4)
                        printk(KERN_DEBUG "macmace: jabbering transceiver\n");
}

static irqreturn_t mace_interrupt(int irq, void *dev_id)
{
        struct net_device *dev = (struct net_device *) dev_id;
        struct mace_data *mp = netdev_priv(dev);
        volatile struct mace *mb = mp->mace;
        int intr, fs;
        unsigned long flags;

        /* don't want the dma interrupt handler to fire */
        local_irq_save(flags);

        intr = mb->ir; /* read interrupt register */
        mace_handle_misc_intrs(dev, intr);

        if (intr & XMTINT) {
                fs = mb->xmtfs;
                if ((fs & XMTSV) == 0) {
                        printk(KERN_ERR "macmace: xmtfs not valid! (fs=%x)\n", fs);
                        mace_reset(dev);
                        /*
                         * XXX mace likes to hang the machine after a xmtfs error.
                         * This is hard to reproduce, resetting *may* help
                         */
                }
                /* dma should have finished */
                if (!mp->tx_count) {
                        printk(KERN_DEBUG "macmace: tx ring ran out? (fs=%x)\n", fs);
                }
                /* Update stats */
                if (fs & (UFLO|LCOL|LCAR|RTRY)) {
                        ++dev->stats.tx_errors;
                        if (fs & LCAR)
                                ++dev->stats.tx_carrier_errors;
                        else if (fs & (UFLO|LCOL|RTRY)) {
                                ++dev->stats.tx_aborted_errors;
                                if (mb->xmtfs & UFLO) {
                                        dev->stats.tx_fifo_errors++;
                                        mace_txdma_reset(dev);
                                }
                        }
                }
        }

        if (mp->tx_count)
                netif_wake_queue(dev);

        local_irq_restore(flags);

        return IRQ_HANDLED;
}

static void mace_tx_timeout(struct net_device *dev, unsigned int txqueue)
{
        struct mace_data *mp = netdev_priv(dev);
        volatile struct mace *mb = mp->mace;
        unsigned long flags;

        local_irq_save(flags);

        /* turn off both tx and rx and reset the chip */
        mb->maccc = 0;
        printk(KERN_ERR "macmace: transmit timeout - resetting\n");
        mace_txdma_reset(dev);
        mace_reset(dev);

        /* restart rx dma */
        mace_rxdma_reset(dev);

        mp->tx_count = N_TX_RING;
        netif_wake_queue(dev);

        /* turn it on! */
        mb->maccc = ENXMT | ENRCV;
        /* enable all interrupts except receive interrupts */
        mb->imr = RCVINT;

        local_irq_restore(flags);
}

/*
 * Handle a newly arrived frame
 */

static void mace_dma_rx_frame(struct net_device *dev, struct mace_frame *mf)
{
        struct sk_buff *skb;
        unsigned int frame_status = mf->rcvsts;

        if (frame_status & (RS_OFLO | RS_CLSN | RS_FRAMERR | RS_FCSERR)) {
                dev->stats.rx_errors++;
                if (frame_status & RS_OFLO)
                        dev->stats.rx_fifo_errors++;
                if (frame_status & RS_CLSN)
                        dev->stats.collisions++;
                if (frame_status & RS_FRAMERR)
                        dev->stats.rx_frame_errors++;
                if (frame_status & RS_FCSERR)
                        dev->stats.rx_crc_errors++;
        } else {
                unsigned int frame_length = mf->rcvcnt + ((frame_status & 0x0F) << 8 );

                skb = netdev_alloc_skb(dev, frame_length + 2);
                if (!skb) {
                        dev->stats.rx_dropped++;
                        return;
                }
                skb_reserve(skb, 2);
                skb_put_data(skb, mf->data, frame_length);

                skb->protocol = eth_type_trans(skb, dev);
                netif_rx(skb);
                dev->stats.rx_packets++;
                dev->stats.rx_bytes += frame_length;
        }
}

/*
 * The PSC has passed us a DMA interrupt event.
 */

static irqreturn_t mace_dma_intr(int irq, void *dev_id)
{
        struct net_device *dev = (struct net_device *) dev_id;
        struct mace_data *mp = netdev_priv(dev);
        int left, head;
        u16 status;
        u32 baka;

        /* Not sure what this does */

        while ((baka = psc_read_long(PSC_MYSTERY)) != psc_read_long(PSC_MYSTERY));
        if (!(baka & 0x60000000)) return IRQ_NONE;

        /*
         * Process the read queue
         */

        status = psc_read_word(PSC_ENETRD_CTL);

        if (status & 0x2000) {
                mace_rxdma_reset(dev);
        } else if (status & 0x0100) {
                psc_write_word(PSC_ENETRD_CMD + mp->rx_slot, 0x1100);

                left = psc_read_long(PSC_ENETRD_LEN + mp->rx_slot);
                head = N_RX_RING - left;

                /* Loop through the ring buffer and process new packages */

                while (mp->rx_tail < head) {
                        mace_dma_rx_frame(dev, (struct mace_frame*) (mp->rx_ring
                                + (mp->rx_tail * MACE_BUFF_SIZE)));
                        mp->rx_tail++;
                }

                /* If we're out of buffers in this ring then switch to */
                /* the other set, otherwise just reactivate this one.  */

                if (!left) {
                        mace_load_rxdma_base(dev, mp->rx_slot);
                        mp->rx_slot ^= 0x10;
                } else {
                        psc_write_word(PSC_ENETRD_CMD + mp->rx_slot, 0x9800);
                }
        }

        /*
         * Process the write queue
         */

        status = psc_read_word(PSC_ENETWR_CTL);

        if (status & 0x2000) {
                mace_txdma_reset(dev);
        } else if (status & 0x0100) {
                psc_write_word(PSC_ENETWR_CMD + mp->tx_sloti, 0x0100);
                mp->tx_sloti ^= 0x10;
                mp->tx_count++;
        }
        return IRQ_HANDLED;
}

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Macintosh MACE ethernet driver");
MODULE_ALIAS("platform:macmace");

static void mac_mace_device_remove(struct platform_device *pdev)
{
        struct net_device *dev = platform_get_drvdata(pdev);
        struct mace_data *mp = netdev_priv(dev);

        unregister_netdev(dev);

        free_irq(dev->irq, dev);
        free_irq(IRQ_MAC_MACE_DMA, dev);

        dma_free_coherent(mp->device, N_RX_RING * MACE_BUFF_SIZE,
                          mp->rx_ring, mp->rx_ring_phys);
        dma_free_coherent(mp->device, N_TX_RING * MACE_BUFF_SIZE,
                          mp->tx_ring, mp->tx_ring_phys);

        free_netdev(dev);
}

static struct platform_driver mac_mace_driver = {
        .probe  = mace_probe,
        .remove = mac_mace_device_remove,
        .driver = {
                .name   = mac_mace_string,
        },
};

module_platform_driver(mac_mace_driver);