/* cs89x0.c: A Crystal Semiconductor (Now Cirrus Logic) CS89[02]0
 *           driver for linux.
 * Written 1996 by Russell Nelson, with reference to skeleton.c
 * written 1993-1994 by Donald Becker.
 *
 * This software may be used and distributed according to the terms
 * of the GNU General Public License, incorporated herein by reference.
 *
 * The author may be reached at nelson@crynwr.com, Crynwr
 * Software, 521 Pleasant Valley Rd., Potsdam, NY 13676
 *
 * Other contributors:
 * Mike Cruse        : mcruse@cti-ltd.com
 * Russ Nelson
 * Melody Lee        : ethernet@crystal.cirrus.com
 * Alan Cox
 * Andrew Morton
 * Oskar Schirmer    : oskar@scara.com
 * Deepak Saxena     : dsaxena@plexity.net
 * Dmitry Pervushin  : dpervushin@ru.mvista.com
 * Deepak Saxena     : dsaxena@plexity.net
 * Domenico Andreoli : cavokz@gmail.com
 */

/*
 * Set this to zero to remove all the debug statements via
 * dead code elimination
 */
#define DEBUGGING       1

/* Sources:
 *      Crynwr packet driver epktisa.
 *      Crystal Semiconductor data sheets.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/printk.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/jiffies.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/gfp.h>
#include <linux/io.h>

#include <asm/irq.h>
#include <linux/atomic.h>

#include "cs89x0.h"

#define cs89_dbg(val, level, fmt, ...)                          \
do {                                                            \
        if (val <= net_debug)                                   \
                pr_##level(fmt, ##__VA_ARGS__);                 \
} while (0)

static char version[] __initdata =
        "v2.4.3-pre1 Russell Nelson <nelson@crynwr.com>, Andrew Morton";

#define DRV_NAME "cs89x0"
#if DEBUGGING
static unsigned int net_debug = DEBUGGING;
#else
#define net_debug 0     /* gcc will remove all the debug code for us */
#endif

/* The number of low I/O ports used by the ethercard. */
#define NETCARD_IO_EXTENT       16

/* we allow the user to override various values normally set in the EEPROM */
#define FORCE_RJ45      0x0001    /* pick one of these three */
#define FORCE_AUI       0x0002
#define FORCE_BNC       0x0004

#define FORCE_AUTO      0x0010    /* pick one of these three */
#define FORCE_HALF      0x0020
#define FORCE_FULL      0x0030

/* Information that need to be kept for each board. */
struct net_local {
        int chip_type;          /* one of: CS8900, CS8920, CS8920M */
        char chip_revision;     /* revision letter of the chip ('A'...) */
        int send_cmd;           /* the proper send command: TX_NOW, TX_AFTER_381, or TX_AFTER_ALL */
        int auto_neg_cnf;       /* auto-negotiation word from EEPROM */
        int adapter_cnf;        /* adapter configuration from EEPROM */
        int isa_config;         /* ISA configuration from EEPROM */
        int irq_map;            /* IRQ map from EEPROM */
        int rx_mode;            /* what mode are we in? 0, RX_MULTCAST_ACCEPT, or RX_ALL_ACCEPT */
        int curr_rx_cfg;        /* a copy of PP_RxCFG */
        int linectl;            /* either 0 or LOW_RX_SQUELCH, depending on configuration. */
        int send_underrun;      /* keep track of how many underruns in a row we get */
        int force;              /* force various values; see FORCE* above. */
        spinlock_t lock;
        void __iomem *virt_addr;/* CS89x0 virtual address. */
};

/* Example routines you must write ;->. */
#define tx_done(dev) 1

/*
 * Permit 'cs89x0_dma=N' in the kernel boot environment
 */
#if !defined(MODULE)
static int g_cs89x0_media__force;

static int __init media_fn(char *str)
{
        if (!strcmp(str, "rj45"))
                g_cs89x0_media__force = FORCE_RJ45;
        else if (!strcmp(str, "aui"))
                g_cs89x0_media__force = FORCE_AUI;
        else if (!strcmp(str, "bnc"))
                g_cs89x0_media__force = FORCE_BNC;

        return 1;
}

__setup("cs89x0_media=", media_fn);
#endif

static void readwords(struct net_local *lp, int portno, void *buf, int length)
{
        u8 *buf8 = (u8 *)buf;

        do {
                u16 tmp16;

                tmp16 = ioread16(lp->virt_addr + portno);
                *buf8++ = (u8)tmp16;
                *buf8++ = (u8)(tmp16 >> 8);
        } while (--length);
}

static void writewords(struct net_local *lp, int portno, void *buf, int length)
{
        u8 *buf8 = (u8 *)buf;

        do {
                u16 tmp16;

                tmp16 = *buf8++;
                tmp16 |= (*buf8++) << 8;
                iowrite16(tmp16, lp->virt_addr + portno);
        } while (--length);
}

static u16
readreg(struct net_device *dev, u16 regno)
{
        struct net_local *lp = netdev_priv(dev);

        iowrite16(regno, lp->virt_addr + ADD_PORT);
        return ioread16(lp->virt_addr + DATA_PORT);
}

static void
writereg(struct net_device *dev, u16 regno, u16 value)
{
        struct net_local *lp = netdev_priv(dev);

        iowrite16(regno, lp->virt_addr + ADD_PORT);
        iowrite16(value, lp->virt_addr + DATA_PORT);
}

static int __init
wait_eeprom_ready(struct net_device *dev)
{
        unsigned long timeout = jiffies;
        /* check to see if the EEPROM is ready,
         * a timeout is used just in case EEPROM is ready when
         * SI_BUSY in the PP_SelfST is clear
         */
        while (readreg(dev, PP_SelfST) & SI_BUSY)
                if (time_after_eq(jiffies, timeout + 40))
                        return -1;
        return 0;
}

static int __init
get_eeprom_data(struct net_device *dev, int off, int len, int *buffer)
{
        int i;

        cs89_dbg(3, info, "EEPROM data from %x for %x:", off, len);
        for (i = 0; i < len; i++) {
                if (wait_eeprom_ready(dev) < 0)
                        return -1;
                /* Now send the EEPROM read command and EEPROM location to read */
                writereg(dev, PP_EECMD, (off + i) | EEPROM_READ_CMD);
                if (wait_eeprom_ready(dev) < 0)
                        return -1;
                buffer[i] = readreg(dev, PP_EEData);
                cs89_dbg(3, cont, " %04x", buffer[i]);
        }
        cs89_dbg(3, cont, "\n");
        return 0;
}

static int  __init
get_eeprom_cksum(int off, int len, int *buffer)
{
        int i, cksum;

        cksum = 0;
        for (i = 0; i < len; i++)
                cksum += buffer[i];
        cksum &= 0xffff;
        if (cksum == 0)
                return 0;
        return -1;
}

static void
write_irq(struct net_device *dev, int chip_type, int irq)
{
        if (chip_type == CS8900) {
                /* INTRQ0 pin is used for interrupt generation. */
                writereg(dev, PP_CS8900_ISAINT, 0);
        } else {
                writereg(dev, PP_CS8920_ISAINT, irq);
        }
}

static void
count_rx_errors(int status, struct net_device *dev)
{
        dev->stats.rx_errors++;
        if (status & RX_RUNT)
                dev->stats.rx_length_errors++;
        if (status & RX_EXTRA_DATA)
                dev->stats.rx_length_errors++;
        if ((status & RX_CRC_ERROR) && !(status & (RX_EXTRA_DATA | RX_RUNT)))
                /* per str 172 */
                dev->stats.rx_crc_errors++;
        if (status & RX_DRIBBLE)
                dev->stats.rx_frame_errors++;
}

static void
control_dc_dc(struct net_device *dev, int on_not_off)
{
        struct net_local *lp = netdev_priv(dev);
        unsigned int selfcontrol;
        unsigned long timenow = jiffies;
        /* control the DC to DC convertor in the SelfControl register.
         * Note: This is hooked up to a general purpose pin, might not
         * always be a DC to DC convertor.
         */

        selfcontrol = HCB1_ENBL; /* Enable the HCB1 bit as an output */
        if (((lp->adapter_cnf & A_CNF_DC_DC_POLARITY) != 0) ^ on_not_off)
                selfcontrol |= HCB1;
        else
                selfcontrol &= ~HCB1;
        writereg(dev, PP_SelfCTL, selfcontrol);

        /* Wait for the DC/DC converter to power up - 500ms */
        while (time_before(jiffies, timenow + HZ))
                ;
}

/* send a test packet - return true if carrier bits are ok */
static int
send_test_pkt(struct net_device *dev)
{
        struct net_local *lp = netdev_priv(dev);
        char test_packet[] = {
                0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0,
                0, 46,          /* A 46 in network order */
                0, 0,           /* DSAP=0 & SSAP=0 fields */
                0xf3, 0         /* Control (Test Req + P bit set) */
        };
        unsigned long timenow = jiffies;

        writereg(dev, PP_LineCTL, readreg(dev, PP_LineCTL) | SERIAL_TX_ON);

        memcpy(test_packet,            dev->dev_addr, ETH_ALEN);
        memcpy(test_packet + ETH_ALEN, dev->dev_addr, ETH_ALEN);

        iowrite16(TX_AFTER_ALL, lp->virt_addr + TX_CMD_PORT);
        iowrite16(ETH_ZLEN, lp->virt_addr + TX_LEN_PORT);

        /* Test to see if the chip has allocated memory for the packet */
        while (time_before(jiffies, timenow + 5))
                if (readreg(dev, PP_BusST) & READY_FOR_TX_NOW)
                        break;
        if (time_after_eq(jiffies, timenow + 5))
                return 0;       /* this shouldn't happen */

        /* Write the contents of the packet */
        writewords(lp, TX_FRAME_PORT, test_packet, (ETH_ZLEN + 1) >> 1);

        cs89_dbg(1, debug, "Sending test packet ");
        /* wait a couple of jiffies for packet to be received */
        for (timenow = jiffies; time_before(jiffies, timenow + 3);)
                ;
        if ((readreg(dev, PP_TxEvent) & TX_SEND_OK_BITS) == TX_OK) {
                cs89_dbg(1, cont, "succeeded\n");
                return 1;
        }
        cs89_dbg(1, cont, "failed\n");
        return 0;
}

#define DETECTED_NONE  0
#define DETECTED_RJ45H 1
#define DETECTED_RJ45F 2
#define DETECTED_AUI   3
#define DETECTED_BNC   4

static int
detect_tp(struct net_device *dev)
{
        struct net_local *lp = netdev_priv(dev);
        unsigned long timenow = jiffies;
        int fdx;

        cs89_dbg(1, debug, "%s: Attempting TP\n", dev->name);

        /* If connected to another full duplex capable 10-Base-T card
         * the link pulses seem to be lost when the auto detect bit in
         * the LineCTL is set.  To overcome this the auto detect bit will
         * be cleared whilst testing the 10-Base-T interface.  This would
         * not be necessary for the sparrow chip but is simpler to do it
         * anyway.
         */
        writereg(dev, PP_LineCTL, lp->linectl & ~AUI_ONLY);
        control_dc_dc(dev, 0);

        /* Delay for the hardware to work out if the TP cable is present
         * - 150ms
         */
        for (timenow = jiffies; time_before(jiffies, timenow + 15);)
                ;
        if ((readreg(dev, PP_LineST) & LINK_OK) == 0)
                return DETECTED_NONE;

        if (lp->chip_type == CS8900) {
                switch (lp->force & 0xf0) {
#if 0
                case FORCE_AUTO:
                        pr_info("%s: cs8900 doesn't autonegotiate\n",
                                dev->name);
                        return DETECTED_NONE;
#endif
                        /* CS8900 doesn't support AUTO, change to HALF*/
                case FORCE_AUTO:
                        lp->force &= ~FORCE_AUTO;
                        lp->force |= FORCE_HALF;
                        break;
                case FORCE_HALF:
                        break;
                case FORCE_FULL:
                        writereg(dev, PP_TestCTL,
                                 readreg(dev, PP_TestCTL) | FDX_8900);
                        break;
                }
                fdx = readreg(dev, PP_TestCTL) & FDX_8900;
        } else {
                switch (lp->force & 0xf0) {
                case FORCE_AUTO:
                        lp->auto_neg_cnf = AUTO_NEG_ENABLE;
                        break;
                case FORCE_HALF:
                        lp->auto_neg_cnf = 0;
                        break;
                case FORCE_FULL:
                        lp->auto_neg_cnf = RE_NEG_NOW | ALLOW_FDX;
                        break;
                }

                writereg(dev, PP_AutoNegCTL, lp->auto_neg_cnf & AUTO_NEG_MASK);

                if ((lp->auto_neg_cnf & AUTO_NEG_BITS) == AUTO_NEG_ENABLE) {
                        pr_info("%s: negotiating duplex...\n", dev->name);
                        while (readreg(dev, PP_AutoNegST) & AUTO_NEG_BUSY) {
                                if (time_after(jiffies, timenow + 4000)) {
                                        pr_err("**** Full / half duplex auto-negotiation timed out ****\n");
                                        break;
                                }
                        }
                }
                fdx = readreg(dev, PP_AutoNegST) & FDX_ACTIVE;
        }
        if (fdx)
                return DETECTED_RJ45F;
        else
                return DETECTED_RJ45H;
}

static int
detect_bnc(struct net_device *dev)
{
        struct net_local *lp = netdev_priv(dev);

        cs89_dbg(1, debug, "%s: Attempting BNC\n", dev->name);
        control_dc_dc(dev, 1);

        writereg(dev, PP_LineCTL, (lp->linectl & ~AUTO_AUI_10BASET) | AUI_ONLY);

        if (send_test_pkt(dev))
                return DETECTED_BNC;
        else
                return DETECTED_NONE;
}

static int
detect_aui(struct net_device *dev)
{
        struct net_local *lp = netdev_priv(dev);

        cs89_dbg(1, debug, "%s: Attempting AUI\n", dev->name);
        control_dc_dc(dev, 0);

        writereg(dev, PP_LineCTL, (lp->linectl & ~AUTO_AUI_10BASET) | AUI_ONLY);

        if (send_test_pkt(dev))
                return DETECTED_AUI;
        else
                return DETECTED_NONE;
}

/* We have a good packet(s), get it/them out of the buffers. */
static void
net_rx(struct net_device *dev)
{
        struct net_local *lp = netdev_priv(dev);
        struct sk_buff *skb;
        int status, length;

        status = ioread16(lp->virt_addr + RX_FRAME_PORT);
        length = ioread16(lp->virt_addr + RX_FRAME_PORT);

        if ((status & RX_OK) == 0) {
                count_rx_errors(status, dev);
                return;
        }

        /* Malloc up new buffer. */
        skb = netdev_alloc_skb(dev, length + 2);
        if (skb == NULL) {
                dev->stats.rx_dropped++;
                return;
        }
        skb_reserve(skb, 2);    /* longword align L3 header */

        readwords(lp, RX_FRAME_PORT, skb_put(skb, length), length >> 1);
        if (length & 1)
                skb->data[length-1] = ioread16(lp->virt_addr + RX_FRAME_PORT);

        cs89_dbg(3, debug, "%s: received %d byte packet of type %x\n",
                 dev->name, length,
                 (skb->data[ETH_ALEN + ETH_ALEN] << 8) |
                 skb->data[ETH_ALEN + ETH_ALEN + 1]);

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

/* The typical workload of the driver:
 * Handle the network interface interrupts.
 */

static irqreturn_t net_interrupt(int irq, void *dev_id)
{
        struct net_device *dev = dev_id;
        struct net_local *lp;
        int status;
        int handled = 0;

        lp = netdev_priv(dev);

        /* we MUST read all the events out of the ISQ, otherwise we'll never
         * get interrupted again.  As a consequence, we can't have any limit
         * on the number of times we loop in the interrupt handler.  The
         * hardware guarantees that eventually we'll run out of events.  Of
         * course, if you're on a slow machine, and packets are arriving
         * faster than you can read them off, you're screwed.  Hasta la
         * vista, baby!
         */
        while ((status = ioread16(lp->virt_addr + ISQ_PORT))) {
                cs89_dbg(4, debug, "%s: event=%04x\n", dev->name, status);
                handled = 1;
                switch (status & ISQ_EVENT_MASK) {
                case ISQ_RECEIVER_EVENT:
                        /* Got a packet(s). */
                        net_rx(dev);
                        break;
                case ISQ_TRANSMITTER_EVENT:
                        dev->stats.tx_packets++;
                        netif_wake_queue(dev);  /* Inform upper layers. */
                        if ((status & (TX_OK |
                                       TX_LOST_CRS |
                                       TX_SQE_ERROR |
                                       TX_LATE_COL |
                                       TX_16_COL)) != TX_OK) {
                                if ((status & TX_OK) == 0)
                                        dev->stats.tx_errors++;
                                if (status & TX_LOST_CRS)
                                        dev->stats.tx_carrier_errors++;
                                if (status & TX_SQE_ERROR)
                                        dev->stats.tx_heartbeat_errors++;
                                if (status & TX_LATE_COL)
                                        dev->stats.tx_window_errors++;
                                if (status & TX_16_COL)
                                        dev->stats.tx_aborted_errors++;
                        }
                        break;
                case ISQ_BUFFER_EVENT:
                        if (status & READY_FOR_TX) {
                                /* we tried to transmit a packet earlier,
                                 * but inexplicably ran out of buffers.
                                 * That shouldn't happen since we only ever
                                 * load one packet.  Shrug.  Do the right
                                 * thing anyway.
                                 */
                                netif_wake_queue(dev);  /* Inform upper layers. */
                        }
                        if (status & TX_UNDERRUN) {
                                cs89_dbg(0, err, "%s: transmit underrun\n",
                                         dev->name);
                                lp->send_underrun++;
                                if (lp->send_underrun == 3)
                                        lp->send_cmd = TX_AFTER_381;
                                else if (lp->send_underrun == 6)
                                        lp->send_cmd = TX_AFTER_ALL;
                                /* transmit cycle is done, although
                                 * frame wasn't transmitted - this
                                 * avoids having to wait for the upper
                                 * layers to timeout on us, in the
                                 * event of a tx underrun
                                 */
                                netif_wake_queue(dev);  /* Inform upper layers. */
                        }
                        break;
                case ISQ_RX_MISS_EVENT:
                        dev->stats.rx_missed_errors += (status >> 6);
                        break;
                case ISQ_TX_COL_EVENT:
                        dev->stats.collisions += (status >> 6);
                        break;
                }
        }
        return IRQ_RETVAL(handled);
}

/* Open/initialize the board.  This is called (in the current kernel)
   sometime after booting when the 'ifconfig' program is run.

   This routine should set everything up anew at each open, even
   registers that "should" only need to be set once at boot, so that
   there is non-reboot way to recover if something goes wrong.
*/

/* AKPM: do we need to do any locking here? */

static int
net_open(struct net_device *dev)
{
        struct net_local *lp = netdev_priv(dev);
        int result = 0;
        int i;
        int ret;

        if (dev->irq < 2) {
                /* Allow interrupts to be generated by the chip */
/* Cirrus' release had this: */
#if 0
                writereg(dev, PP_BusCTL, readreg(dev, PP_BusCTL) | ENABLE_IRQ);
#endif
/* And 2.3.47 had this: */
                writereg(dev, PP_BusCTL, ENABLE_IRQ | MEMORY_ON);

                for (i = 2; i < CS8920_NO_INTS; i++) {
                        if ((1 << i) & lp->irq_map) {
                                if (request_irq(i, net_interrupt, 0, dev->name,
                                                dev) == 0) {
                                        dev->irq = i;
                                        write_irq(dev, lp->chip_type, i);
                                        /* writereg(dev, PP_BufCFG, GENERATE_SW_INTERRUPT); */
                                        break;
                                }
                        }
                }

                if (i >= CS8920_NO_INTS) {
                        writereg(dev, PP_BusCTL, 0);    /* disable interrupts. */
                        pr_err("can't get an interrupt\n");
                        ret = -EAGAIN;
                        goto bad_out;
                }
        } else {
/* FIXME: Cirrus' release had this: */
                writereg(dev, PP_BusCTL, readreg(dev, PP_BusCTL)|ENABLE_IRQ);
/* And 2.3.47 had this: */
#if 0
                writereg(dev, PP_BusCTL, ENABLE_IRQ | MEMORY_ON);
#endif
                write_irq(dev, lp->chip_type, dev->irq);
                ret = request_irq(dev->irq, net_interrupt, 0, dev->name, dev);
                if (ret) {
                        pr_err("request_irq(%d) failed\n", dev->irq);
                        goto bad_out;
                }
        }

        /* set the Ethernet address */
        for (i = 0; i < ETH_ALEN / 2; i++)
                writereg(dev, PP_IA + i * 2,
                         (dev->dev_addr[i * 2] |
                          (dev->dev_addr[i * 2 + 1] << 8)));

        /* while we're testing the interface, leave interrupts disabled */
        writereg(dev, PP_BusCTL, MEMORY_ON);

        /* Set the LineCTL quintuplet based on adapter configuration read from EEPROM */
        if ((lp->adapter_cnf & A_CNF_EXTND_10B_2) &&
            (lp->adapter_cnf & A_CNF_LOW_RX_SQUELCH))
                lp->linectl = LOW_RX_SQUELCH;
        else
                lp->linectl = 0;

        /* check to make sure that they have the "right" hardware available */
        switch (lp->adapter_cnf & A_CNF_MEDIA_TYPE) {
        case A_CNF_MEDIA_10B_T:
                result = lp->adapter_cnf & A_CNF_10B_T;
                break;
        case A_CNF_MEDIA_AUI:
                result = lp->adapter_cnf & A_CNF_AUI;
                break;
        case A_CNF_MEDIA_10B_2:
                result = lp->adapter_cnf & A_CNF_10B_2;
                break;
        default:
                result = lp->adapter_cnf & (A_CNF_10B_T |
                                            A_CNF_AUI |
                                            A_CNF_10B_2);
        }
        if (!result) {
                pr_err("%s: EEPROM is configured for unavailable media\n",
                       dev->name);
release_dma:
                writereg(dev, PP_LineCTL,
                         readreg(dev, PP_LineCTL) & ~(SERIAL_TX_ON | SERIAL_RX_ON));
                free_irq(dev->irq, dev);
                ret = -EAGAIN;
                goto bad_out;
        }

        /* set the hardware to the configured choice */
        switch (lp->adapter_cnf & A_CNF_MEDIA_TYPE) {
        case A_CNF_MEDIA_10B_T:
                result = detect_tp(dev);
                if (result == DETECTED_NONE) {
                        pr_warn("%s: 10Base-T (RJ-45) has no cable\n",
                                dev->name);
                        if (lp->auto_neg_cnf & IMM_BIT) /* check "ignore missing media" bit */
                                result = DETECTED_RJ45H; /* Yes! I don't care if I see a link pulse */
                }
                break;
        case A_CNF_MEDIA_AUI:
                result = detect_aui(dev);
                if (result == DETECTED_NONE) {
                        pr_warn("%s: 10Base-5 (AUI) has no cable\n", dev->name);
                        if (lp->auto_neg_cnf & IMM_BIT) /* check "ignore missing media" bit */
                                result = DETECTED_AUI; /* Yes! I don't care if I see a carrier */
                }
                break;
        case A_CNF_MEDIA_10B_2:
                result = detect_bnc(dev);
                if (result == DETECTED_NONE) {
                        pr_warn("%s: 10Base-2 (BNC) has no cable\n", dev->name);
                        if (lp->auto_neg_cnf & IMM_BIT) /* check "ignore missing media" bit */
                                result = DETECTED_BNC; /* Yes! I don't care if I can xmit a packet */
                }
                break;
        case A_CNF_MEDIA_AUTO:
                writereg(dev, PP_LineCTL, lp->linectl | AUTO_AUI_10BASET);
                if (lp->adapter_cnf & A_CNF_10B_T) {
                        result = detect_tp(dev);
                        if (result != DETECTED_NONE)
                                break;
                }
                if (lp->adapter_cnf & A_CNF_AUI) {
                        result = detect_aui(dev);
                        if (result != DETECTED_NONE)
                                break;
                }
                if (lp->adapter_cnf & A_CNF_10B_2) {
                        result = detect_bnc(dev);
                        if (result != DETECTED_NONE)
                                break;
                }
                pr_err("%s: no media detected\n", dev->name);
                goto release_dma;
        }
        switch (result) {
        case DETECTED_NONE:
                pr_err("%s: no network cable attached to configured media\n",
                       dev->name);
                goto release_dma;
        case DETECTED_RJ45H:
                pr_info("%s: using half-duplex 10Base-T (RJ-45)\n", dev->name);
                break;
        case DETECTED_RJ45F:
                pr_info("%s: using full-duplex 10Base-T (RJ-45)\n", dev->name);
                break;
        case DETECTED_AUI:
                pr_info("%s: using 10Base-5 (AUI)\n", dev->name);
                break;
        case DETECTED_BNC:
                pr_info("%s: using 10Base-2 (BNC)\n", dev->name);
                break;
        }

        /* Turn on both receive and transmit operations */
        writereg(dev, PP_LineCTL,
                 readreg(dev, PP_LineCTL) | SERIAL_RX_ON | SERIAL_TX_ON);

        /* Receive only error free packets addressed to this card */
        lp->rx_mode = 0;
        writereg(dev, PP_RxCTL, DEF_RX_ACCEPT);

        lp->curr_rx_cfg = RX_OK_ENBL | RX_CRC_ERROR_ENBL;

        if (lp->isa_config & STREAM_TRANSFER)
                lp->curr_rx_cfg |= RX_STREAM_ENBL;
        writereg(dev, PP_RxCFG, lp->curr_rx_cfg);

        writereg(dev, PP_TxCFG, (TX_LOST_CRS_ENBL |
                                 TX_SQE_ERROR_ENBL |
                                 TX_OK_ENBL |
                                 TX_LATE_COL_ENBL |
                                 TX_JBR_ENBL |
                                 TX_ANY_COL_ENBL |
                                 TX_16_COL_ENBL));

        writereg(dev, PP_BufCFG, (READY_FOR_TX_ENBL |
                                  RX_MISS_COUNT_OVRFLOW_ENBL |
                                  TX_COL_COUNT_OVRFLOW_ENBL |
                                  TX_UNDERRUN_ENBL));

        /* now that we've got our act together, enable everything */
        writereg(dev, PP_BusCTL,
                 (ENABLE_IRQ | (dev->mem_start ? MEMORY_ON : 0))); /* turn memory on */
        netif_start_queue(dev);
        cs89_dbg(1, debug, "net_open() succeeded\n");
        return 0;
bad_out:
        return ret;
}

/* The inverse routine to net_open(). */
static int
net_close(struct net_device *dev)
{
        netif_stop_queue(dev);

        writereg(dev, PP_RxCFG, 0);
        writereg(dev, PP_TxCFG, 0);
        writereg(dev, PP_BufCFG, 0);
        writereg(dev, PP_BusCTL, 0);

        free_irq(dev->irq, dev);

        /* Update the statistics here. */
        return 0;
}

/* Get the current statistics.
 * This may be called with the card open or closed.
 */
static struct net_device_stats *
net_get_stats(struct net_device *dev)
{
        struct net_local *lp = netdev_priv(dev);
        unsigned long flags;

        spin_lock_irqsave(&lp->lock, flags);
        /* Update the statistics from the device registers. */
        dev->stats.rx_missed_errors += (readreg(dev, PP_RxMiss) >> 6);
        dev->stats.collisions += (readreg(dev, PP_TxCol) >> 6);
        spin_unlock_irqrestore(&lp->lock, flags);

        return &dev->stats;
}

static void net_timeout(struct net_device *dev, unsigned int txqueue)
{
        /* If we get here, some higher level has decided we are broken.
           There should really be a "kick me" function call instead. */
        cs89_dbg(0, err, "%s: transmit timed out, %s?\n",
                 dev->name,
                 tx_done(dev) ? "IRQ conflict" : "network cable problem");
        /* Try to restart the adaptor. */
        netif_wake_queue(dev);
}

static netdev_tx_t net_send_packet(struct sk_buff *skb, struct net_device *dev)
{
        struct net_local *lp = netdev_priv(dev);
        unsigned long flags;

        cs89_dbg(3, debug, "%s: sent %d byte packet of type %x\n",
                 dev->name, skb->len,
                 ((skb->data[ETH_ALEN + ETH_ALEN] << 8) |
                  skb->data[ETH_ALEN + ETH_ALEN + 1]));

        /* keep the upload from being interrupted, since we
         * ask the chip to start transmitting before the
         * whole packet has been completely uploaded.
         */

        spin_lock_irqsave(&lp->lock, flags);
        netif_stop_queue(dev);

        /* initiate a transmit sequence */
        iowrite16(lp->send_cmd, lp->virt_addr + TX_CMD_PORT);
        iowrite16(skb->len, lp->virt_addr + TX_LEN_PORT);

        /* Test to see if the chip has allocated memory for the packet */
        if ((readreg(dev, PP_BusST) & READY_FOR_TX_NOW) == 0) {
                /* Gasp!  It hasn't.  But that shouldn't happen since
                 * we're waiting for TxOk, so return 1 and requeue this packet.
                 */

                spin_unlock_irqrestore(&lp->lock, flags);
                cs89_dbg(0, err, "Tx buffer not free!\n");
                return NETDEV_TX_BUSY;
        }
        /* Write the contents of the packet */
        writewords(lp, TX_FRAME_PORT, skb->data, (skb->len + 1) >> 1);
        spin_unlock_irqrestore(&lp->lock, flags);
        dev->stats.tx_bytes += skb->len;
        dev_consume_skb_any(skb);

        /* We DO NOT call netif_wake_queue() here.
         * We also DO NOT call netif_start_queue().
         *
         * Either of these would cause another bottom half run through
         * net_send_packet() before this packet has fully gone out.
         * That causes us to hit the "Gasp!" above and the send is rescheduled.
         * it runs like a dog.  We just return and wait for the Tx completion
         * interrupt handler to restart the netdevice layer
         */

        return NETDEV_TX_OK;
}

static void set_multicast_list(struct net_device *dev)
{
        struct net_local *lp = netdev_priv(dev);
        unsigned long flags;
        u16 cfg;

        spin_lock_irqsave(&lp->lock, flags);
        if (dev->flags & IFF_PROMISC)
                lp->rx_mode = RX_ALL_ACCEPT;
        else if ((dev->flags & IFF_ALLMULTI) || !netdev_mc_empty(dev))
                /* The multicast-accept list is initialized to accept-all,
                 * and we rely on higher-level filtering for now.
                 */
                lp->rx_mode = RX_MULTCAST_ACCEPT;
        else
                lp->rx_mode = 0;

        writereg(dev, PP_RxCTL, DEF_RX_ACCEPT | lp->rx_mode);

        /* in promiscuous mode, we accept errored packets,
         * so we have to enable interrupts on them also
         */
        cfg = lp->curr_rx_cfg;
        if (lp->rx_mode == RX_ALL_ACCEPT)
                cfg |= RX_CRC_ERROR_ENBL | RX_RUNT_ENBL | RX_EXTRA_DATA_ENBL;
        writereg(dev, PP_RxCFG, cfg);
        spin_unlock_irqrestore(&lp->lock, flags);
}

static int set_mac_address(struct net_device *dev, void *p)
{
        int i;
        struct sockaddr *addr = p;

        if (netif_running(dev))
                return -EBUSY;

        eth_hw_addr_set(dev, addr->sa_data);

        cs89_dbg(0, debug, "%s: Setting MAC address to %pM\n",
                 dev->name, dev->dev_addr);

        /* set the Ethernet address */
        for (i = 0; i < ETH_ALEN / 2; i++)
                writereg(dev, PP_IA + i * 2,
                         (dev->dev_addr[i * 2] |
                          (dev->dev_addr[i * 2 + 1] << 8)));

        return 0;
}

#ifdef CONFIG_NET_POLL_CONTROLLER
/*
 * Polling receive - used by netconsole and other diagnostic tools
 * to allow network i/o with interrupts disabled.
 */
static void net_poll_controller(struct net_device *dev)
{
        disable_irq(dev->irq);
        net_interrupt(dev->irq, dev);
        enable_irq(dev->irq);
}
#endif

static const struct net_device_ops net_ops = {
        .ndo_open               = net_open,
        .ndo_stop               = net_close,
        .ndo_tx_timeout         = net_timeout,
        .ndo_start_xmit         = net_send_packet,
        .ndo_get_stats          = net_get_stats,
        .ndo_set_rx_mode        = set_multicast_list,
        .ndo_set_mac_address    = set_mac_address,
#ifdef CONFIG_NET_POLL_CONTROLLER
        .ndo_poll_controller    = net_poll_controller,
#endif
        .ndo_validate_addr      = eth_validate_addr,
};

static void __init reset_chip(struct net_device *dev)
{
        struct net_local *lp = netdev_priv(dev);
        unsigned long reset_start_time;

        writereg(dev, PP_SelfCTL, readreg(dev, PP_SelfCTL) | POWER_ON_RESET);

        /* wait 30 ms */
        msleep(30);

        if (lp->chip_type != CS8900) {
                /* Hardware problem requires PNP registers to be reconfigured after a reset */
                iowrite16(PP_CS8920_ISAINT, lp->virt_addr + ADD_PORT);
                iowrite8(dev->irq, lp->virt_addr + DATA_PORT);
                iowrite8(0, lp->virt_addr + DATA_PORT + 1);

                iowrite16(PP_CS8920_ISAMemB, lp->virt_addr + ADD_PORT);
                iowrite8((dev->mem_start >> 16) & 0xff,
                         lp->virt_addr + DATA_PORT);
                iowrite8((dev->mem_start >> 8) & 0xff,
                         lp->virt_addr + DATA_PORT + 1);
        }

        /* Wait until the chip is reset */
        reset_start_time = jiffies;
        while ((readreg(dev, PP_SelfST) & INIT_DONE) == 0 &&
               time_before(jiffies, reset_start_time + 2))
                ;
}

/* This is the real probe routine.
 * Linux has a history of friendly device probes on the ISA bus.
 * A good device probes avoids doing writes, and
 * verifies that the correct device exists and functions.
 * Return 0 on success.
 */
static int __init
cs89x0_probe1(struct net_device *dev, void __iomem *ioaddr, int modular)
{
        struct net_local *lp = netdev_priv(dev);
        int i;
        int tmp;
        unsigned rev_type = 0;
        int eeprom_buff[CHKSUM_LEN];
        u8 addr[ETH_ALEN];
        int retval;

        /* Initialize the device structure. */
        if (!modular) {
                memset(lp, 0, sizeof(*lp));
                spin_lock_init(&lp->lock);
#ifndef MODULE
                lp->force = g_cs89x0_media__force;
#endif
        }

        pr_debug("PP_addr at %p[%x]: 0x%x\n",
                 ioaddr, ADD_PORT, ioread16(ioaddr + ADD_PORT));
        iowrite16(PP_ChipID, ioaddr + ADD_PORT);

        tmp = ioread16(ioaddr + DATA_PORT);
        if (tmp != CHIP_EISA_ID_SIG) {
                pr_debug("%s: incorrect signature at %p[%x]: 0x%x!="
                         CHIP_EISA_ID_SIG_STR "\n",
                         dev->name, ioaddr, DATA_PORT, tmp);
                retval = -ENODEV;
                goto out1;
        }

        lp->virt_addr = ioaddr;

        /* get the chip type */
        rev_type = readreg(dev, PRODUCT_ID_ADD);
        lp->chip_type = rev_type & ~REVISON_BITS;
        lp->chip_revision = ((rev_type & REVISON_BITS) >> 8) + 'A';

        /* Check the chip type and revision in order to set the correct
         * send command.  CS8920 revision C and CS8900 revision F can use
         * the faster send.
         */
        lp->send_cmd = TX_AFTER_381;
        if (lp->chip_type == CS8900 && lp->chip_revision >= 'F')
                lp->send_cmd = TX_NOW;
        if (lp->chip_type != CS8900 && lp->chip_revision >= 'C')
                lp->send_cmd = TX_NOW;

        pr_info_once("%s\n", version);

        pr_info("%s: cs89%c0%s rev %c found at %p ",
                dev->name,
                lp->chip_type == CS8900  ? '0' : '2',
                lp->chip_type == CS8920M ? "M" : "",
                lp->chip_revision,
                lp->virt_addr);

        reset_chip(dev);

        /* Here we read the current configuration of the chip.
         * If there is no Extended EEPROM then the idea is to not disturb
         * the chip configuration, it should have been correctly setup by
         * automatic EEPROM read on reset. So, if the chip says it read
         * the EEPROM the driver will always do *something* instead of
         * complain that adapter_cnf is 0.
         */

        if ((readreg(dev, PP_SelfST) & (EEPROM_OK | EEPROM_PRESENT)) ==
            (EEPROM_OK | EEPROM_PRESENT)) {
                /* Load the MAC. */
                for (i = 0; i < ETH_ALEN / 2; i++) {
                        unsigned int Addr;
                        Addr = readreg(dev, PP_IA + i * 2);
                        addr[i * 2] = Addr & 0xFF;
                        addr[i * 2 + 1] = Addr >> 8;
                }
                eth_hw_addr_set(dev, addr);

                /* Load the Adapter Configuration.
                 * Note:  Barring any more specific information from some
                 * other source (ie EEPROM+Schematics), we would not know
                 * how to operate a 10Base2 interface on the AUI port.
                 * However, since we  do read the status of HCB1 and use
                 * settings that always result in calls to control_dc_dc(dev,0)
                 * a BNC interface should work if the enable pin
                 * (dc/dc converter) is on HCB1.
                 * It will be called AUI however.
                 */

                lp->adapter_cnf = 0;
                i = readreg(dev, PP_LineCTL);
                /* Preserve the setting of the HCB1 pin. */
                if ((i & (HCB1 | HCB1_ENBL)) == (HCB1 | HCB1_ENBL))
                        lp->adapter_cnf |= A_CNF_DC_DC_POLARITY;
                /* Save the sqelch bit */
                if ((i & LOW_RX_SQUELCH) == LOW_RX_SQUELCH)
                        lp->adapter_cnf |= A_CNF_EXTND_10B_2 | A_CNF_LOW_RX_SQUELCH;
                /* Check if the card is in 10Base-t only mode */
                if ((i & (AUI_ONLY | AUTO_AUI_10BASET)) == 0)
                        lp->adapter_cnf |=  A_CNF_10B_T | A_CNF_MEDIA_10B_T;
                /* Check if the card is in AUI only mode */
                if ((i & (AUI_ONLY | AUTO_AUI_10BASET)) == AUI_ONLY)
                        lp->adapter_cnf |=  A_CNF_AUI | A_CNF_MEDIA_AUI;
                /* Check if the card is in Auto mode. */
                if ((i & (AUI_ONLY | AUTO_AUI_10BASET)) == AUTO_AUI_10BASET)
                        lp->adapter_cnf |=  A_CNF_AUI | A_CNF_10B_T |
                                A_CNF_MEDIA_AUI | A_CNF_MEDIA_10B_T | A_CNF_MEDIA_AUTO;

                cs89_dbg(1, info, "%s: PP_LineCTL=0x%x, adapter_cnf=0x%x\n",
                         dev->name, i, lp->adapter_cnf);

                /* IRQ. Other chips already probe, see below. */
                if (lp->chip_type == CS8900)
                        lp->isa_config = readreg(dev, PP_CS8900_ISAINT) & INT_NO_MASK;

                pr_cont("[Cirrus EEPROM] ");
        }

        pr_cont("\n");

        /* First check to see if an EEPROM is attached. */

        if ((readreg(dev, PP_SelfST) & EEPROM_PRESENT) == 0)
                pr_warn("No EEPROM, relying on command line....\n");
        else if (get_eeprom_data(dev, START_EEPROM_DATA, CHKSUM_LEN, eeprom_buff) < 0) {
                pr_warn("EEPROM read failed, relying on command line\n");
        } else if (get_eeprom_cksum(START_EEPROM_DATA, CHKSUM_LEN, eeprom_buff) < 0) {
                /* Check if the chip was able to read its own configuration starting
                   at 0 in the EEPROM*/
                if ((readreg(dev, PP_SelfST) & (EEPROM_OK | EEPROM_PRESENT)) !=
                    (EEPROM_OK | EEPROM_PRESENT))
                        pr_warn("Extended EEPROM checksum bad and no Cirrus EEPROM, relying on command line\n");

        } else {
                /* This reads an extended EEPROM that is not documented
                 * in the CS8900 datasheet.
                 */

                /* get transmission control word  but keep the autonegotiation bits */
                if (!lp->auto_neg_cnf)
                        lp->auto_neg_cnf = eeprom_buff[AUTO_NEG_CNF_OFFSET / 2];
                /* Store adapter configuration */
                if (!lp->adapter_cnf)
                        lp->adapter_cnf = eeprom_buff[ADAPTER_CNF_OFFSET / 2];
                /* Store ISA configuration */
                lp->isa_config = eeprom_buff[ISA_CNF_OFFSET / 2];
                dev->mem_start = eeprom_buff[PACKET_PAGE_OFFSET / 2] << 8;

                /* eeprom_buff has 32-bit ints, so we can't just memcpy it */
                /* store the initial memory base address */
                for (i = 0; i < ETH_ALEN / 2; i++) {
                        addr[i * 2] = eeprom_buff[i];
                        addr[i * 2 + 1] = eeprom_buff[i] >> 8;
                }
                eth_hw_addr_set(dev, addr);
                cs89_dbg(1, debug, "%s: new adapter_cnf: 0x%x\n",
                         dev->name, lp->adapter_cnf);
        }

        /* allow them to force multiple transceivers.  If they force multiple, autosense */
        {
                int count = 0;
                if (lp->force & FORCE_RJ45) {
                        lp->adapter_cnf |= A_CNF_10B_T;
                        count++;
                }
                if (lp->force & FORCE_AUI) {
                        lp->adapter_cnf |= A_CNF_AUI;
                        count++;
                }
                if (lp->force & FORCE_BNC) {
                        lp->adapter_cnf |= A_CNF_10B_2;
                        count++;
                }
                if (count > 1)
                        lp->adapter_cnf |= A_CNF_MEDIA_AUTO;
                else if (lp->force & FORCE_RJ45)
                        lp->adapter_cnf |= A_CNF_MEDIA_10B_T;
                else if (lp->force & FORCE_AUI)
                        lp->adapter_cnf |= A_CNF_MEDIA_AUI;
                else if (lp->force & FORCE_BNC)
                        lp->adapter_cnf |= A_CNF_MEDIA_10B_2;
        }

        cs89_dbg(1, debug, "%s: after force 0x%x, adapter_cnf=0x%x\n",
                 dev->name, lp->force, lp->adapter_cnf);

        /* FIXME: We don't let you set dc-dc polarity or low RX squelch from the command line: add it here */

        /* FIXME: We don't let you set the IMM bit from the command line: add it to lp->auto_neg_cnf here */

        /* FIXME: we don't set the Ethernet address on the command line.  Use
         * ifconfig IFACE hw ether AABBCCDDEEFF
         */

        pr_info("media %s%s%s",
                (lp->adapter_cnf & A_CNF_10B_T) ? "RJ-45," : "",
                (lp->adapter_cnf & A_CNF_AUI) ? "AUI," : "",
                (lp->adapter_cnf & A_CNF_10B_2) ? "BNC," : "");

        lp->irq_map = 0xffff;

        /* If this is a CS8900 then no pnp soft */
        if (lp->chip_type != CS8900 &&
            /* Check if the ISA IRQ has been set  */
            (i = readreg(dev, PP_CS8920_ISAINT) & 0xff,
             (i != 0 && i < CS8920_NO_INTS))) {
                if (!dev->irq)
                        dev->irq = i;
        } else {
                i = lp->isa_config & INT_NO_MASK;
                if (!dev->irq)
                        dev->irq = i;
        }

        pr_cont(" IRQ %d", dev->irq);
        pr_cont(", programmed I/O");

        /* print the ethernet address. */
        pr_cont(", MAC %pM\n", dev->dev_addr);

        dev->netdev_ops = &net_ops;
        dev->watchdog_timeo = HZ;

        cs89_dbg(0, info, "cs89x0_probe1() successful\n");

        retval = register_netdev(dev);
        if (retval)
                goto out2;
        return 0;
out2:
        iowrite16(PP_ChipID, lp->virt_addr + ADD_PORT);
out1:
        return retval;
}

static int __init cs89x0_platform_probe(struct platform_device *pdev)
{
        struct net_device *dev = alloc_etherdev(sizeof(struct net_local));
        void __iomem *virt_addr;
        int err;

        if (!dev)
                return -ENOMEM;

        dev->irq = platform_get_irq(pdev, 0);
        if (dev->irq < 0) {
                err = dev->irq;
                goto free;
        }

        virt_addr = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(virt_addr)) {
                err = PTR_ERR(virt_addr);
                goto free;
        }

        err = cs89x0_probe1(dev, virt_addr, 0);
        if (err) {
                dev_warn(&dev->dev, "no cs8900 or cs8920 detected\n");
                goto free;
        }

        platform_set_drvdata(pdev, dev);
        return 0;

free:
        free_netdev(dev);
        return err;
}

static void cs89x0_platform_remove(struct platform_device *pdev)
{
        struct net_device *dev = platform_get_drvdata(pdev);

        /* This platform_get_resource() call will not return NULL, because
         * the same call in cs89x0_platform_probe() has returned a non NULL
         * value.
         */
        unregister_netdev(dev);
        free_netdev(dev);
}

static const struct of_device_id __maybe_unused cs89x0_match[] = {
        { .compatible = "cirrus,cs8900", },
        { .compatible = "cirrus,cs8920", },
        { },
};
MODULE_DEVICE_TABLE(of, cs89x0_match);

static struct platform_driver cs89x0_driver = {
        .driver = {
                .name           = DRV_NAME,
                .of_match_table = of_match_ptr(cs89x0_match),
        },
        .remove = cs89x0_platform_remove,
};

module_platform_driver_probe(cs89x0_driver, cs89x0_platform_probe);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Crystal Semiconductor (Now Cirrus Logic) CS89[02]0 network driver");
MODULE_AUTHOR("Russell Nelson <nelson@crynwr.com>");