/*
 *  Driver for the IDT RC32434 (Korina) on-chip ethernet controller.
 *
 *  Copyright 2004 IDT Inc. (rischelp@idt.com)
 *  Copyright 2006 Felix Fietkau <nbd@openwrt.org>
 *  Copyright 2008 Florian Fainelli <florian@openwrt.org>
 *  Copyright 2017 Roman Yeryomin <roman@advem.lv>
 *
 *  This program is free software; you can redistribute  it and/or modify it
 *  under  the terms of  the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
 *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
 *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
 *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *  You should have received a copy of the  GNU General Public License along
 *  with this program; if not, write  to the Free Software Foundation, Inc.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *  Writing to a DMA status register:
 *
 *  When writing to the status register, you should mask the bit you have
 *  been testing the status register with. Both Tx and Rx DMA registers
 *  should stick to this procedure.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/moduleparam.h>
#include <linux/sched.h>
#include <linux/ctype.h>
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/iopoll.h>
#include <linux/in.h>
#include <linux/of.h>
#include <linux/of_net.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/errno.h>
#include <linux/platform_device.h>
#include <linux/mii.h>
#include <linux/ethtool.h>
#include <linux/crc32.h>
#include <linux/pgtable.h>
#include <linux/clk.h>

#define DRV_NAME        "korina"
#define DRV_VERSION     "0.20"
#define DRV_RELDATE     "15Sep2017"

struct eth_regs {
        u32 ethintfc;
        u32 ethfifott;
        u32 etharc;
        u32 ethhash0;
        u32 ethhash1;
        u32 ethu0[4];           /* Reserved. */
        u32 ethpfs;
        u32 ethmcp;
        u32 eth_u1[10];         /* Reserved. */
        u32 ethspare;
        u32 eth_u2[42];         /* Reserved. */
        u32 ethsal0;
        u32 ethsah0;
        u32 ethsal1;
        u32 ethsah1;
        u32 ethsal2;
        u32 ethsah2;
        u32 ethsal3;
        u32 ethsah3;
        u32 ethrbc;
        u32 ethrpc;
        u32 ethrupc;
        u32 ethrfc;
        u32 ethtbc;
        u32 ethgpf;
        u32 eth_u9[50];         /* Reserved. */
        u32 ethmac1;
        u32 ethmac2;
        u32 ethipgt;
        u32 ethipgr;
        u32 ethclrt;
        u32 ethmaxf;
        u32 eth_u10;            /* Reserved. */
        u32 ethmtest;
        u32 miimcfg;
        u32 miimcmd;
        u32 miimaddr;
        u32 miimwtd;
        u32 miimrdd;
        u32 miimind;
        u32 eth_u11;            /* Reserved. */
        u32 eth_u12;            /* Reserved. */
        u32 ethcfsa0;
        u32 ethcfsa1;
        u32 ethcfsa2;
};

/* Ethernet interrupt registers */
#define ETH_INT_FC_EN           BIT(0)
#define ETH_INT_FC_ITS          BIT(1)
#define ETH_INT_FC_RIP          BIT(2)
#define ETH_INT_FC_JAM          BIT(3)
#define ETH_INT_FC_OVR          BIT(4)
#define ETH_INT_FC_UND          BIT(5)
#define ETH_INT_FC_IOC          0x000000c0

/* Ethernet FIFO registers */
#define ETH_FIFI_TT_TTH_BIT     0
#define ETH_FIFO_TT_TTH         0x0000007f

/* Ethernet ARC/multicast registers */
#define ETH_ARC_PRO             BIT(0)
#define ETH_ARC_AM              BIT(1)
#define ETH_ARC_AFM             BIT(2)
#define ETH_ARC_AB              BIT(3)

/* Ethernet SAL registers */
#define ETH_SAL_BYTE_5          0x000000ff
#define ETH_SAL_BYTE_4          0x0000ff00
#define ETH_SAL_BYTE_3          0x00ff0000
#define ETH_SAL_BYTE_2          0xff000000

/* Ethernet SAH registers */
#define ETH_SAH_BYTE1           0x000000ff
#define ETH_SAH_BYTE0           0x0000ff00

/* Ethernet GPF register */
#define ETH_GPF_PTV             0x0000ffff

/* Ethernet PFG register */
#define ETH_PFS_PFD             BIT(0)

/* Ethernet CFSA[0-3] registers */
#define ETH_CFSA0_CFSA4         0x000000ff
#define ETH_CFSA0_CFSA5         0x0000ff00
#define ETH_CFSA1_CFSA2         0x000000ff
#define ETH_CFSA1_CFSA3         0x0000ff00
#define ETH_CFSA1_CFSA0         0x000000ff
#define ETH_CFSA1_CFSA1         0x0000ff00

/* Ethernet MAC1 registers */
#define ETH_MAC1_RE             BIT(0)
#define ETH_MAC1_PAF            BIT(1)
#define ETH_MAC1_RFC            BIT(2)
#define ETH_MAC1_TFC            BIT(3)
#define ETH_MAC1_LB             BIT(4)
#define ETH_MAC1_MR             BIT(31)

/* Ethernet MAC2 registers */
#define ETH_MAC2_FD             BIT(0)
#define ETH_MAC2_FLC            BIT(1)
#define ETH_MAC2_HFE            BIT(2)
#define ETH_MAC2_DC             BIT(3)
#define ETH_MAC2_CEN            BIT(4)
#define ETH_MAC2_PE             BIT(5)
#define ETH_MAC2_VPE            BIT(6)
#define ETH_MAC2_APE            BIT(7)
#define ETH_MAC2_PPE            BIT(8)
#define ETH_MAC2_LPE            BIT(9)
#define ETH_MAC2_NB             BIT(12)
#define ETH_MAC2_BP             BIT(13)
#define ETH_MAC2_ED             BIT(14)

/* Ethernet IPGT register */
#define ETH_IPGT                0x0000007f

/* Ethernet IPGR registers */
#define ETH_IPGR_IPGR2          0x0000007f
#define ETH_IPGR_IPGR1          0x00007f00

/* Ethernet CLRT registers */
#define ETH_CLRT_MAX_RET        0x0000000f
#define ETH_CLRT_COL_WIN        0x00003f00

/* Ethernet MAXF register */
#define ETH_MAXF                0x0000ffff

/* Ethernet test registers */
#define ETH_TEST_REG            BIT(2)
#define ETH_MCP_DIV             0x000000ff

/* MII registers */
#define ETH_MII_CFG_RSVD        0x0000000c
#define ETH_MII_CMD_RD          BIT(0)
#define ETH_MII_CMD_SCN         BIT(1)
#define ETH_MII_REG_ADDR        0x0000001f
#define ETH_MII_PHY_ADDR        0x00001f00
#define ETH_MII_WTD_DATA        0x0000ffff
#define ETH_MII_RDD_DATA        0x0000ffff
#define ETH_MII_IND_BSY         BIT(0)
#define ETH_MII_IND_SCN         BIT(1)
#define ETH_MII_IND_NV          BIT(2)

/* Values for the DEVCS field of the Ethernet DMA Rx and Tx descriptors. */
#define ETH_RX_FD               BIT(0)
#define ETH_RX_LD               BIT(1)
#define ETH_RX_ROK              BIT(2)
#define ETH_RX_FM               BIT(3)
#define ETH_RX_MP               BIT(4)
#define ETH_RX_BP               BIT(5)
#define ETH_RX_VLT              BIT(6)
#define ETH_RX_CF               BIT(7)
#define ETH_RX_OVR              BIT(8)
#define ETH_RX_CRC              BIT(9)
#define ETH_RX_CV               BIT(10)
#define ETH_RX_DB               BIT(11)
#define ETH_RX_LE               BIT(12)
#define ETH_RX_LOR              BIT(13)
#define ETH_RX_CES              BIT(14)
#define ETH_RX_LEN_BIT          16
#define ETH_RX_LEN              0xffff0000

#define ETH_TX_FD               BIT(0)
#define ETH_TX_LD               BIT(1)
#define ETH_TX_OEN              BIT(2)
#define ETH_TX_PEN              BIT(3)
#define ETH_TX_CEN              BIT(4)
#define ETH_TX_HEN              BIT(5)
#define ETH_TX_TOK              BIT(6)
#define ETH_TX_MP               BIT(7)
#define ETH_TX_BP               BIT(8)
#define ETH_TX_UND              BIT(9)
#define ETH_TX_OF               BIT(10)
#define ETH_TX_ED               BIT(11)
#define ETH_TX_EC               BIT(12)
#define ETH_TX_LC               BIT(13)
#define ETH_TX_TD               BIT(14)
#define ETH_TX_CRC              BIT(15)
#define ETH_TX_LE               BIT(16)
#define ETH_TX_CC               0x001E0000

/* DMA descriptor (in physical memory). */
struct dma_desc {
        u32 control;                    /* Control. use DMAD_* */
        u32 ca;                         /* Current Address. */
        u32 devcs;                      /* Device control and status. */
        u32 link;                       /* Next descriptor in chain. */
};

#define DMA_DESC_COUNT_BIT              0
#define DMA_DESC_COUNT_MSK              0x0003ffff
#define DMA_DESC_DS_BIT                 20
#define DMA_DESC_DS_MSK                 0x00300000

#define DMA_DESC_DEV_CMD_BIT            22
#define DMA_DESC_DEV_CMD_MSK            0x01c00000

/* DMA descriptors interrupts */
#define DMA_DESC_COF                    BIT(25) /* Chain on finished */
#define DMA_DESC_COD                    BIT(26) /* Chain on done */
#define DMA_DESC_IOF                    BIT(27) /* Interrupt on finished */
#define DMA_DESC_IOD                    BIT(28) /* Interrupt on done */
#define DMA_DESC_TERM                   BIT(29) /* Terminated */
#define DMA_DESC_DONE                   BIT(30) /* Done */
#define DMA_DESC_FINI                   BIT(31) /* Finished */

/* DMA register (within Internal Register Map).  */
struct dma_reg {
        u32 dmac;               /* Control. */
        u32 dmas;               /* Status. */
        u32 dmasm;              /* Mask. */
        u32 dmadptr;            /* Descriptor pointer. */
        u32 dmandptr;           /* Next descriptor pointer. */
};

/* DMA channels specific registers */
#define DMA_CHAN_RUN_BIT                BIT(0)
#define DMA_CHAN_DONE_BIT               BIT(1)
#define DMA_CHAN_MODE_BIT               BIT(2)
#define DMA_CHAN_MODE_MSK               0x0000000c
#define  DMA_CHAN_MODE_AUTO             0
#define  DMA_CHAN_MODE_BURST            1
#define  DMA_CHAN_MODE_XFRT             2
#define  DMA_CHAN_MODE_RSVD             3
#define DMA_CHAN_ACT_BIT                BIT(4)

/* DMA status registers */
#define DMA_STAT_FINI                   BIT(0)
#define DMA_STAT_DONE                   BIT(1)
#define DMA_STAT_CHAIN                  BIT(2)
#define DMA_STAT_ERR                    BIT(3)
#define DMA_STAT_HALT                   BIT(4)

#define STATION_ADDRESS_HIGH(dev) (((dev)->dev_addr[0] << 8) | \
                                   ((dev)->dev_addr[1]))
#define STATION_ADDRESS_LOW(dev)  (((dev)->dev_addr[2] << 24) | \
                                   ((dev)->dev_addr[3] << 16) | \
                                   ((dev)->dev_addr[4] << 8)  | \
                                   ((dev)->dev_addr[5]))

#define MII_CLOCK       1250000 /* no more than 2.5MHz */

/* the following must be powers of two */
#define KORINA_NUM_RDS  64  /* number of receive descriptors */
#define KORINA_NUM_TDS  64  /* number of transmit descriptors */

/* KORINA_RBSIZE is the hardware's default maximum receive
 * frame size in bytes. Having this hardcoded means that there
 * is no support for MTU sizes greater than 1500. */
#define KORINA_RBSIZE   1536 /* size of one resource buffer = Ether MTU */
#define KORINA_RDS_MASK (KORINA_NUM_RDS - 1)
#define KORINA_TDS_MASK (KORINA_NUM_TDS - 1)
#define RD_RING_SIZE    (KORINA_NUM_RDS * sizeof(struct dma_desc))
#define TD_RING_SIZE    (KORINA_NUM_TDS * sizeof(struct dma_desc))

#define TX_TIMEOUT      (6000 * HZ / 1000)

enum chain_status {
        desc_filled,
        desc_is_empty
};

#define DMA_COUNT(count)        ((count) & DMA_DESC_COUNT_MSK)
#define IS_DMA_FINISHED(X)      (((X) & (DMA_DESC_FINI)) != 0)
#define IS_DMA_DONE(X)          (((X) & (DMA_DESC_DONE)) != 0)
#define RCVPKT_LENGTH(X)        (((X) & ETH_RX_LEN) >> ETH_RX_LEN_BIT)

/* Information that need to be kept for each board. */
struct korina_private {
        struct eth_regs __iomem *eth_regs;
        struct dma_reg __iomem *rx_dma_regs;
        struct dma_reg __iomem *tx_dma_regs;
        struct dma_desc *td_ring; /* transmit descriptor ring */
        struct dma_desc *rd_ring; /* receive descriptor ring  */
        dma_addr_t td_dma;
        dma_addr_t rd_dma;

        struct sk_buff *tx_skb[KORINA_NUM_TDS];
        struct sk_buff *rx_skb[KORINA_NUM_RDS];

        dma_addr_t rx_skb_dma[KORINA_NUM_RDS];
        dma_addr_t tx_skb_dma[KORINA_NUM_TDS];

        int rx_next_done;
        int rx_chain_head;
        int rx_chain_tail;
        enum chain_status rx_chain_status;

        int tx_next_done;
        int tx_chain_head;
        int tx_chain_tail;
        enum chain_status tx_chain_status;
        int tx_count;
        int tx_full;

        int rx_irq;
        int tx_irq;

        spinlock_t lock;        /* NIC xmit lock */

        int dma_halt_cnt;
        int dma_run_cnt;
        struct napi_struct napi;
        struct timer_list media_check_timer;
        struct mii_if_info mii_if;
        struct work_struct restart_task;
        struct net_device *dev;
        struct device *dmadev;
        int mii_clock_freq;
};

static dma_addr_t korina_tx_dma(struct korina_private *lp, int idx)
{
        return lp->td_dma + (idx * sizeof(struct dma_desc));
}

static dma_addr_t korina_rx_dma(struct korina_private *lp, int idx)
{
        return lp->rd_dma + (idx * sizeof(struct dma_desc));
}

static inline void korina_abort_dma(struct net_device *dev,
                                        struct dma_reg *ch)
{
        if (readl(&ch->dmac) & DMA_CHAN_RUN_BIT) {
                writel(0x10, &ch->dmac);

                while (!(readl(&ch->dmas) & DMA_STAT_HALT))
                        netif_trans_update(dev);

                writel(0, &ch->dmas);
        }

        writel(0, &ch->dmadptr);
        writel(0, &ch->dmandptr);
}

static void korina_abort_tx(struct net_device *dev)
{
        struct korina_private *lp = netdev_priv(dev);

        korina_abort_dma(dev, lp->tx_dma_regs);
}

static void korina_abort_rx(struct net_device *dev)
{
        struct korina_private *lp = netdev_priv(dev);

        korina_abort_dma(dev, lp->rx_dma_regs);
}

/* transmit packet */
static netdev_tx_t korina_send_packet(struct sk_buff *skb,
                                      struct net_device *dev)
{
        struct korina_private *lp = netdev_priv(dev);
        u32 chain_prev, chain_next;
        unsigned long flags;
        struct dma_desc *td;
        dma_addr_t ca;
        u32 length;
        int idx;

        spin_lock_irqsave(&lp->lock, flags);

        idx = lp->tx_chain_tail;
        td = &lp->td_ring[idx];

        /* stop queue when full, drop pkts if queue already full */
        if (lp->tx_count >= (KORINA_NUM_TDS - 2)) {
                lp->tx_full = 1;

                if (lp->tx_count == (KORINA_NUM_TDS - 2))
                        netif_stop_queue(dev);
                else
                        goto drop_packet;
        }

        lp->tx_count++;

        lp->tx_skb[idx] = skb;

        length = skb->len;

        /* Setup the transmit descriptor. */
        ca = dma_map_single(lp->dmadev, skb->data, length, DMA_TO_DEVICE);
        if (dma_mapping_error(lp->dmadev, ca))
                goto drop_packet;

        lp->tx_skb_dma[idx] = ca;
        td->ca = ca;

        chain_prev = (idx - 1) & KORINA_TDS_MASK;
        chain_next = (idx + 1) & KORINA_TDS_MASK;

        if (readl(&(lp->tx_dma_regs->dmandptr)) == 0) {
                if (lp->tx_chain_status == desc_is_empty) {
                        /* Update tail */
                        td->control = DMA_COUNT(length) |
                                        DMA_DESC_COF | DMA_DESC_IOF;
                        /* Move tail */
                        lp->tx_chain_tail = chain_next;
                        /* Write to NDPTR */
                        writel(korina_tx_dma(lp, lp->tx_chain_head),
                               &lp->tx_dma_regs->dmandptr);
                        /* Move head to tail */
                        lp->tx_chain_head = lp->tx_chain_tail;
                } else {
                        /* Update tail */
                        td->control = DMA_COUNT(length) |
                                        DMA_DESC_COF | DMA_DESC_IOF;
                        /* Link to prev */
                        lp->td_ring[chain_prev].control &=
                                        ~DMA_DESC_COF;
                        /* Link to prev */
                        lp->td_ring[chain_prev].link = korina_tx_dma(lp, idx);
                        /* Move tail */
                        lp->tx_chain_tail = chain_next;
                        /* Write to NDPTR */
                        writel(korina_tx_dma(lp, lp->tx_chain_head),
                               &lp->tx_dma_regs->dmandptr);
                        /* Move head to tail */
                        lp->tx_chain_head = lp->tx_chain_tail;
                        lp->tx_chain_status = desc_is_empty;
                }
        } else {
                if (lp->tx_chain_status == desc_is_empty) {
                        /* Update tail */
                        td->control = DMA_COUNT(length) |
                                        DMA_DESC_COF | DMA_DESC_IOF;
                        /* Move tail */
                        lp->tx_chain_tail = chain_next;
                        lp->tx_chain_status = desc_filled;
                } else {
                        /* Update tail */
                        td->control = DMA_COUNT(length) |
                                        DMA_DESC_COF | DMA_DESC_IOF;
                        lp->td_ring[chain_prev].control &=
                                        ~DMA_DESC_COF;
                        lp->td_ring[chain_prev].link = korina_tx_dma(lp, idx);
                        lp->tx_chain_tail = chain_next;
                }
        }

        netif_trans_update(dev);
        spin_unlock_irqrestore(&lp->lock, flags);

        return NETDEV_TX_OK;

drop_packet:
        dev->stats.tx_dropped++;
        dev_kfree_skb_any(skb);
        spin_unlock_irqrestore(&lp->lock, flags);

        return NETDEV_TX_OK;
}

static int korina_mdio_wait(struct korina_private *lp)
{
        u32 value;

        return readl_poll_timeout_atomic(&lp->eth_regs->miimind,
                                         value, value & ETH_MII_IND_BSY,
                                         1, 1000);
}

static int korina_mdio_read(struct net_device *dev, int phy, int reg)
{
        struct korina_private *lp = netdev_priv(dev);
        int ret;

        ret = korina_mdio_wait(lp);
        if (ret < 0)
                return ret;

        writel(phy << 8 | reg, &lp->eth_regs->miimaddr);
        writel(1, &lp->eth_regs->miimcmd);

        ret = korina_mdio_wait(lp);
        if (ret < 0)
                return ret;

        if (readl(&lp->eth_regs->miimind) & ETH_MII_IND_NV)
                return -EINVAL;

        ret = readl(&lp->eth_regs->miimrdd);
        writel(0, &lp->eth_regs->miimcmd);
        return ret;
}

static void korina_mdio_write(struct net_device *dev, int phy, int reg, int val)
{
        struct korina_private *lp = netdev_priv(dev);

        if (korina_mdio_wait(lp))
                return;

        writel(0, &lp->eth_regs->miimcmd);
        writel(phy << 8 | reg, &lp->eth_regs->miimaddr);
        writel(val, &lp->eth_regs->miimwtd);
}

/* Ethernet Rx DMA interrupt */
static irqreturn_t korina_rx_dma_interrupt(int irq, void *dev_id)
{
        struct net_device *dev = dev_id;
        struct korina_private *lp = netdev_priv(dev);
        u32 dmas, dmasm;
        irqreturn_t retval;

        dmas = readl(&lp->rx_dma_regs->dmas);
        if (dmas & (DMA_STAT_DONE | DMA_STAT_HALT | DMA_STAT_ERR)) {
                dmasm = readl(&lp->rx_dma_regs->dmasm);
                writel(dmasm | (DMA_STAT_DONE |
                                DMA_STAT_HALT | DMA_STAT_ERR),
                                &lp->rx_dma_regs->dmasm);

                napi_schedule(&lp->napi);

                if (dmas & DMA_STAT_ERR)
                        printk(KERN_ERR "%s: DMA error\n", dev->name);

                retval = IRQ_HANDLED;
        } else
                retval = IRQ_NONE;

        return retval;
}

static int korina_rx(struct net_device *dev, int limit)
{
        struct korina_private *lp = netdev_priv(dev);
        struct dma_desc *rd = &lp->rd_ring[lp->rx_next_done];
        struct sk_buff *skb, *skb_new;
        u32 devcs, pkt_len, dmas;
        dma_addr_t ca;
        int count;

        for (count = 0; count < limit; count++) {
                skb = lp->rx_skb[lp->rx_next_done];
                skb_new = NULL;

                devcs = rd->devcs;

                if ((KORINA_RBSIZE - (u32)DMA_COUNT(rd->control)) == 0)
                        break;

                /* check that this is a whole packet
                 * WARNING: DMA_FD bit incorrectly set
                 * in Rc32434 (errata ref #077) */
                if (!(devcs & ETH_RX_LD))
                        goto next;

                if (!(devcs & ETH_RX_ROK)) {
                        /* Update statistics counters */
                        dev->stats.rx_errors++;
                        dev->stats.rx_dropped++;
                        if (devcs & ETH_RX_CRC)
                                dev->stats.rx_crc_errors++;
                        if (devcs & ETH_RX_LE)
                                dev->stats.rx_length_errors++;
                        if (devcs & ETH_RX_OVR)
                                dev->stats.rx_fifo_errors++;
                        if (devcs & ETH_RX_CV)
                                dev->stats.rx_frame_errors++;
                        if (devcs & ETH_RX_CES)
                                dev->stats.rx_frame_errors++;

                        goto next;
                }

                /* Malloc up new buffer. */
                skb_new = netdev_alloc_skb_ip_align(dev, KORINA_RBSIZE);
                if (!skb_new)
                        break;

                ca = dma_map_single(lp->dmadev, skb_new->data, KORINA_RBSIZE,
                                    DMA_FROM_DEVICE);
                if (dma_mapping_error(lp->dmadev, ca)) {
                        dev_kfree_skb_any(skb_new);
                        break;
                }

                pkt_len = RCVPKT_LENGTH(devcs);
                dma_unmap_single(lp->dmadev, lp->rx_skb_dma[lp->rx_next_done],
                                 pkt_len, DMA_FROM_DEVICE);

                /* Do not count the CRC */
                skb_put(skb, pkt_len - 4);
                skb->protocol = eth_type_trans(skb, dev);

                /* Pass the packet to upper layers */
                napi_gro_receive(&lp->napi, skb);
                dev->stats.rx_packets++;
                dev->stats.rx_bytes += pkt_len;

                /* Update the mcast stats */
                if (devcs & ETH_RX_MP)
                        dev->stats.multicast++;

                lp->rx_skb[lp->rx_next_done] = skb_new;
                lp->rx_skb_dma[lp->rx_next_done] = ca;

next:
                rd->devcs = 0;

                /* Restore descriptor's curr_addr */
                rd->ca = lp->rx_skb_dma[lp->rx_next_done];

                rd->control = DMA_COUNT(KORINA_RBSIZE) |
                        DMA_DESC_COD | DMA_DESC_IOD;
                lp->rd_ring[(lp->rx_next_done - 1) &
                        KORINA_RDS_MASK].control &=
                        ~DMA_DESC_COD;

                lp->rx_next_done = (lp->rx_next_done + 1) & KORINA_RDS_MASK;
                rd = &lp->rd_ring[lp->rx_next_done];
                writel((u32)~DMA_STAT_DONE, &lp->rx_dma_regs->dmas);
        }

        dmas = readl(&lp->rx_dma_regs->dmas);

        if (dmas & DMA_STAT_HALT) {
                writel((u32)~(DMA_STAT_HALT | DMA_STAT_ERR),
                       &lp->rx_dma_regs->dmas);

                lp->dma_halt_cnt++;
                rd->devcs = 0;
                rd->ca = lp->rx_skb_dma[lp->rx_next_done];
                writel(korina_rx_dma(lp, rd - lp->rd_ring),
                       &lp->rx_dma_regs->dmandptr);
        }

        return count;
}

static int korina_poll(struct napi_struct *napi, int budget)
{
        struct korina_private *lp =
                container_of(napi, struct korina_private, napi);
        struct net_device *dev = lp->dev;
        int work_done;

        work_done = korina_rx(dev, budget);
        if (work_done < budget) {
                napi_complete_done(napi, work_done);

                writel(readl(&lp->rx_dma_regs->dmasm) &
                        ~(DMA_STAT_DONE | DMA_STAT_HALT | DMA_STAT_ERR),
                        &lp->rx_dma_regs->dmasm);
        }
        return work_done;
}

/*
 * Set or clear the multicast filter for this adaptor.
 */
static void korina_multicast_list(struct net_device *dev)
{
        struct korina_private *lp = netdev_priv(dev);
        unsigned long flags;
        struct netdev_hw_addr *ha;
        u32 recognise = ETH_ARC_AB;     /* always accept broadcasts */

        /* Set promiscuous mode */
        if (dev->flags & IFF_PROMISC)
                recognise |= ETH_ARC_PRO;

        else if ((dev->flags & IFF_ALLMULTI) || (netdev_mc_count(dev) > 4))
                /* All multicast and broadcast */
                recognise |= ETH_ARC_AM;

        /* Build the hash table */
        if (netdev_mc_count(dev) > 4) {
                u16 hash_table[4] = { 0 };
                u32 crc;

                netdev_for_each_mc_addr(ha, dev) {
                        crc = ether_crc_le(6, ha->addr);
                        crc >>= 26;
                        hash_table[crc >> 4] |= 1 << (15 - (crc & 0xf));
                }
                /* Accept filtered multicast */
                recognise |= ETH_ARC_AFM;

                /* Fill the MAC hash tables with their values */
                writel((u32)(hash_table[1] << 16 | hash_table[0]),
                                        &lp->eth_regs->ethhash0);
                writel((u32)(hash_table[3] << 16 | hash_table[2]),
                                        &lp->eth_regs->ethhash1);
        }

        spin_lock_irqsave(&lp->lock, flags);
        writel(recognise, &lp->eth_regs->etharc);
        spin_unlock_irqrestore(&lp->lock, flags);
}

static void korina_tx(struct net_device *dev)
{
        struct korina_private *lp = netdev_priv(dev);
        struct dma_desc *td = &lp->td_ring[lp->tx_next_done];
        u32 devcs;
        u32 dmas;

        spin_lock(&lp->lock);

        /* Process all desc that are done */
        while (IS_DMA_FINISHED(td->control)) {
                if (lp->tx_full == 1) {
                        netif_wake_queue(dev);
                        lp->tx_full = 0;
                }

                devcs = lp->td_ring[lp->tx_next_done].devcs;
                if ((devcs & (ETH_TX_FD | ETH_TX_LD)) !=
                                (ETH_TX_FD | ETH_TX_LD)) {
                        dev->stats.tx_errors++;
                        dev->stats.tx_dropped++;

                        /* Should never happen */
                        printk(KERN_ERR "%s: split tx ignored\n",
                                                        dev->name);
                } else if (devcs & ETH_TX_TOK) {
                        dev->stats.tx_packets++;
                        dev->stats.tx_bytes +=
                                        lp->tx_skb[lp->tx_next_done]->len;
                } else {
                        dev->stats.tx_errors++;
                        dev->stats.tx_dropped++;

                        /* Underflow */
                        if (devcs & ETH_TX_UND)
                                dev->stats.tx_fifo_errors++;

                        /* Oversized frame */
                        if (devcs & ETH_TX_OF)
                                dev->stats.tx_aborted_errors++;

                        /* Excessive deferrals */
                        if (devcs & ETH_TX_ED)
                                dev->stats.tx_carrier_errors++;

                        /* Collisions: medium busy */
                        if (devcs & ETH_TX_EC)
                                dev->stats.collisions++;

                        /* Late collision */
                        if (devcs & ETH_TX_LC)
                                dev->stats.tx_window_errors++;
                }

                /* We must always free the original skb */
                if (lp->tx_skb[lp->tx_next_done]) {
                        dma_unmap_single(lp->dmadev,
                                         lp->tx_skb_dma[lp->tx_next_done],
                                         lp->tx_skb[lp->tx_next_done]->len,
                                         DMA_TO_DEVICE);
                        dev_kfree_skb_any(lp->tx_skb[lp->tx_next_done]);
                        lp->tx_skb[lp->tx_next_done] = NULL;
                }

                lp->td_ring[lp->tx_next_done].control = DMA_DESC_IOF;
                lp->td_ring[lp->tx_next_done].devcs = ETH_TX_FD | ETH_TX_LD;
                lp->td_ring[lp->tx_next_done].link = 0;
                lp->td_ring[lp->tx_next_done].ca = 0;
                lp->tx_count--;

                /* Go on to next transmission */
                lp->tx_next_done = (lp->tx_next_done + 1) & KORINA_TDS_MASK;
                td = &lp->td_ring[lp->tx_next_done];

        }

        /* Clear the DMA status register */
        dmas = readl(&lp->tx_dma_regs->dmas);
        writel(~dmas, &lp->tx_dma_regs->dmas);

        writel(readl(&lp->tx_dma_regs->dmasm) &
                        ~(DMA_STAT_FINI | DMA_STAT_ERR),
                        &lp->tx_dma_regs->dmasm);

        spin_unlock(&lp->lock);
}

static irqreturn_t
korina_tx_dma_interrupt(int irq, void *dev_id)
{
        struct net_device *dev = dev_id;
        struct korina_private *lp = netdev_priv(dev);
        u32 dmas, dmasm;
        irqreturn_t retval;

        dmas = readl(&lp->tx_dma_regs->dmas);

        if (dmas & (DMA_STAT_FINI | DMA_STAT_ERR)) {
                dmasm = readl(&lp->tx_dma_regs->dmasm);
                writel(dmasm | (DMA_STAT_FINI | DMA_STAT_ERR),
                                &lp->tx_dma_regs->dmasm);

                korina_tx(dev);

                if (lp->tx_chain_status == desc_filled &&
                        (readl(&(lp->tx_dma_regs->dmandptr)) == 0)) {
                        writel(korina_tx_dma(lp, lp->tx_chain_head),
                               &lp->tx_dma_regs->dmandptr);
                        lp->tx_chain_status = desc_is_empty;
                        lp->tx_chain_head = lp->tx_chain_tail;
                        netif_trans_update(dev);
                }
                if (dmas & DMA_STAT_ERR)
                        printk(KERN_ERR "%s: DMA error\n", dev->name);

                retval = IRQ_HANDLED;
        } else
                retval = IRQ_NONE;

        return retval;
}


static void korina_check_media(struct net_device *dev, unsigned int init_media)
{
        struct korina_private *lp = netdev_priv(dev);

        mii_check_media(&lp->mii_if, 1, init_media);

        if (lp->mii_if.full_duplex)
                writel(readl(&lp->eth_regs->ethmac2) | ETH_MAC2_FD,
                                                &lp->eth_regs->ethmac2);
        else
                writel(readl(&lp->eth_regs->ethmac2) & ~ETH_MAC2_FD,
                                                &lp->eth_regs->ethmac2);
}

static void korina_poll_media(struct timer_list *t)
{
        struct korina_private *lp = timer_container_of(lp, t,
                                                       media_check_timer);
        struct net_device *dev = lp->dev;

        korina_check_media(dev, 0);
        mod_timer(&lp->media_check_timer, jiffies + HZ);
}

static void korina_set_carrier(struct mii_if_info *mii)
{
        if (mii->force_media) {
                /* autoneg is off: Link is always assumed to be up */
                if (!netif_carrier_ok(mii->dev))
                        netif_carrier_on(mii->dev);
        } else  /* Let MMI library update carrier status */
                korina_check_media(mii->dev, 0);
}

static int korina_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
{
        struct korina_private *lp = netdev_priv(dev);
        struct mii_ioctl_data *data = if_mii(rq);
        int rc;

        if (!netif_running(dev))
                return -EINVAL;
        spin_lock_irq(&lp->lock);
        rc = generic_mii_ioctl(&lp->mii_if, data, cmd, NULL);
        spin_unlock_irq(&lp->lock);
        korina_set_carrier(&lp->mii_if);

        return rc;
}

/* ethtool helpers */
static void netdev_get_drvinfo(struct net_device *dev,
                                struct ethtool_drvinfo *info)
{
        struct korina_private *lp = netdev_priv(dev);

        strscpy(info->driver, DRV_NAME, sizeof(info->driver));
        strscpy(info->version, DRV_VERSION, sizeof(info->version));
        strscpy(info->bus_info, lp->dev->name, sizeof(info->bus_info));
}

static int netdev_get_link_ksettings(struct net_device *dev,
                                     struct ethtool_link_ksettings *cmd)
{
        struct korina_private *lp = netdev_priv(dev);

        spin_lock_irq(&lp->lock);
        mii_ethtool_get_link_ksettings(&lp->mii_if, cmd);
        spin_unlock_irq(&lp->lock);

        return 0;
}

static int netdev_set_link_ksettings(struct net_device *dev,
                                     const struct ethtool_link_ksettings *cmd)
{
        struct korina_private *lp = netdev_priv(dev);
        int rc;

        spin_lock_irq(&lp->lock);
        rc = mii_ethtool_set_link_ksettings(&lp->mii_if, cmd);
        spin_unlock_irq(&lp->lock);
        korina_set_carrier(&lp->mii_if);

        return rc;
}

static u32 netdev_get_link(struct net_device *dev)
{
        struct korina_private *lp = netdev_priv(dev);

        return mii_link_ok(&lp->mii_if);
}

static const struct ethtool_ops netdev_ethtool_ops = {
        .get_drvinfo            = netdev_get_drvinfo,
        .get_link               = netdev_get_link,
        .get_link_ksettings     = netdev_get_link_ksettings,
        .set_link_ksettings     = netdev_set_link_ksettings,
};

static int korina_alloc_ring(struct net_device *dev)
{
        struct korina_private *lp = netdev_priv(dev);
        struct sk_buff *skb;
        dma_addr_t ca;
        int i;

        /* Initialize the transmit descriptors */
        for (i = 0; i < KORINA_NUM_TDS; i++) {
                lp->td_ring[i].control = DMA_DESC_IOF;
                lp->td_ring[i].devcs = ETH_TX_FD | ETH_TX_LD;
                lp->td_ring[i].ca = 0;
                lp->td_ring[i].link = 0;
        }
        lp->tx_next_done = lp->tx_chain_head = lp->tx_chain_tail =
                        lp->tx_full = lp->tx_count = 0;
        lp->tx_chain_status = desc_is_empty;

        /* Initialize the receive descriptors */
        for (i = 0; i < KORINA_NUM_RDS; i++) {
                skb = netdev_alloc_skb_ip_align(dev, KORINA_RBSIZE);
                if (!skb)
                        return -ENOMEM;
                lp->rx_skb[i] = skb;
                lp->rd_ring[i].control = DMA_DESC_IOD |
                                DMA_COUNT(KORINA_RBSIZE);
                lp->rd_ring[i].devcs = 0;
                ca = dma_map_single(lp->dmadev, skb->data, KORINA_RBSIZE,
                                    DMA_FROM_DEVICE);
                if (dma_mapping_error(lp->dmadev, ca))
                        return -ENOMEM;
                lp->rd_ring[i].ca = ca;
                lp->rx_skb_dma[i] = ca;
                lp->rd_ring[i].link = korina_rx_dma(lp, i + 1);
        }

        /* loop back receive descriptors, so the last
         * descriptor points to the first one */
        lp->rd_ring[i - 1].link = lp->rd_dma;
        lp->rd_ring[i - 1].control |= DMA_DESC_COD;

        lp->rx_next_done  = 0;
        lp->rx_chain_head = 0;
        lp->rx_chain_tail = 0;
        lp->rx_chain_status = desc_is_empty;

        return 0;
}

static void korina_free_ring(struct net_device *dev)
{
        struct korina_private *lp = netdev_priv(dev);
        int i;

        for (i = 0; i < KORINA_NUM_RDS; i++) {
                lp->rd_ring[i].control = 0;
                if (lp->rx_skb[i]) {
                        dma_unmap_single(lp->dmadev, lp->rx_skb_dma[i],
                                         KORINA_RBSIZE, DMA_FROM_DEVICE);
                        dev_kfree_skb_any(lp->rx_skb[i]);
                        lp->rx_skb[i] = NULL;
                }
        }

        for (i = 0; i < KORINA_NUM_TDS; i++) {
                lp->td_ring[i].control = 0;
                if (lp->tx_skb[i]) {
                        dma_unmap_single(lp->dmadev, lp->tx_skb_dma[i],
                                         lp->tx_skb[i]->len, DMA_TO_DEVICE);
                        dev_kfree_skb_any(lp->tx_skb[i]);
                        lp->tx_skb[i] = NULL;
                }
        }
}

/*
 * Initialize the RC32434 ethernet controller.
 */
static int korina_init(struct net_device *dev)
{
        struct korina_private *lp = netdev_priv(dev);

        /* Disable DMA */
        korina_abort_tx(dev);
        korina_abort_rx(dev);

        /* reset ethernet logic */
        writel(0, &lp->eth_regs->ethintfc);
        while ((readl(&lp->eth_regs->ethintfc) & ETH_INT_FC_RIP))
                netif_trans_update(dev);

        /* Enable Ethernet Interface */
        writel(ETH_INT_FC_EN, &lp->eth_regs->ethintfc);

        /* Allocate rings */
        if (korina_alloc_ring(dev)) {
                printk(KERN_ERR "%s: descriptor allocation failed\n", dev->name);
                korina_free_ring(dev);
                return -ENOMEM;
        }

        writel(0, &lp->rx_dma_regs->dmas);
        /* Start Rx DMA */
        writel(0, &lp->rx_dma_regs->dmandptr);
        writel(korina_rx_dma(lp, 0), &lp->rx_dma_regs->dmadptr);

        writel(readl(&lp->tx_dma_regs->dmasm) &
                        ~(DMA_STAT_FINI | DMA_STAT_ERR),
                        &lp->tx_dma_regs->dmasm);
        writel(readl(&lp->rx_dma_regs->dmasm) &
                        ~(DMA_STAT_DONE | DMA_STAT_HALT | DMA_STAT_ERR),
                        &lp->rx_dma_regs->dmasm);

        /* Accept only packets destined for this Ethernet device address */
        writel(ETH_ARC_AB, &lp->eth_regs->etharc);

        /* Set all Ether station address registers to their initial values */
        writel(STATION_ADDRESS_LOW(dev), &lp->eth_regs->ethsal0);
        writel(STATION_ADDRESS_HIGH(dev), &lp->eth_regs->ethsah0);

        writel(STATION_ADDRESS_LOW(dev), &lp->eth_regs->ethsal1);
        writel(STATION_ADDRESS_HIGH(dev), &lp->eth_regs->ethsah1);

        writel(STATION_ADDRESS_LOW(dev), &lp->eth_regs->ethsal2);
        writel(STATION_ADDRESS_HIGH(dev), &lp->eth_regs->ethsah2);

        writel(STATION_ADDRESS_LOW(dev), &lp->eth_regs->ethsal3);
        writel(STATION_ADDRESS_HIGH(dev), &lp->eth_regs->ethsah3);


        /* Frame Length Checking, Pad Enable, CRC Enable, Full Duplex set */
        writel(ETH_MAC2_PE | ETH_MAC2_CEN | ETH_MAC2_FD,
                        &lp->eth_regs->ethmac2);

        /* Back to back inter-packet-gap */
        writel(0x15, &lp->eth_regs->ethipgt);
        /* Non - Back to back inter-packet-gap */
        writel(0x12, &lp->eth_regs->ethipgr);

        /* Management Clock Prescaler Divisor
         * Clock independent setting */
        writel(((lp->mii_clock_freq) / MII_CLOCK + 1) & ~1,
               &lp->eth_regs->ethmcp);
        writel(0, &lp->eth_regs->miimcfg);

        /* don't transmit until fifo contains 48b */
        writel(48, &lp->eth_regs->ethfifott);

        writel(ETH_MAC1_RE, &lp->eth_regs->ethmac1);

        korina_check_media(dev, 1);

        napi_enable(&lp->napi);
        netif_start_queue(dev);

        return 0;
}

/*
 * Restart the RC32434 ethernet controller.
 */
static void korina_restart_task(struct work_struct *work)
{
        struct korina_private *lp = container_of(work,
                        struct korina_private, restart_task);
        struct net_device *dev = lp->dev;

        /*
         * Disable interrupts
         */
        disable_irq(lp->rx_irq);
        disable_irq(lp->tx_irq);

        writel(readl(&lp->tx_dma_regs->dmasm) |
                                DMA_STAT_FINI | DMA_STAT_ERR,
                                &lp->tx_dma_regs->dmasm);
        writel(readl(&lp->rx_dma_regs->dmasm) |
                                DMA_STAT_DONE | DMA_STAT_HALT | DMA_STAT_ERR,
                                &lp->rx_dma_regs->dmasm);

        napi_disable(&lp->napi);

        korina_free_ring(dev);

        if (korina_init(dev) < 0) {
                printk(KERN_ERR "%s: cannot restart device\n", dev->name);
                return;
        }
        korina_multicast_list(dev);

        enable_irq(lp->tx_irq);
        enable_irq(lp->rx_irq);
}

static void korina_tx_timeout(struct net_device *dev, unsigned int txqueue)
{
        struct korina_private *lp = netdev_priv(dev);

        schedule_work(&lp->restart_task);
}

#ifdef CONFIG_NET_POLL_CONTROLLER
static void korina_poll_controller(struct net_device *dev)
{
        disable_irq(dev->irq);
        korina_tx_dma_interrupt(dev->irq, dev);
        enable_irq(dev->irq);
}
#endif

static int korina_open(struct net_device *dev)
{
        struct korina_private *lp = netdev_priv(dev);
        int ret;

        /* Initialize */
        ret = korina_init(dev);
        if (ret < 0) {
                printk(KERN_ERR "%s: cannot open device\n", dev->name);
                goto out;
        }

        /* Install the interrupt handler
         * that handles the Done Finished */
        ret = request_irq(lp->rx_irq, korina_rx_dma_interrupt,
                        0, "Korina ethernet Rx", dev);
        if (ret < 0) {
                printk(KERN_ERR "%s: unable to get Rx DMA IRQ %d\n",
                        dev->name, lp->rx_irq);
                goto err_release;
        }
        ret = request_irq(lp->tx_irq, korina_tx_dma_interrupt,
                        0, "Korina ethernet Tx", dev);
        if (ret < 0) {
                printk(KERN_ERR "%s: unable to get Tx DMA IRQ %d\n",
                        dev->name, lp->tx_irq);
                goto err_free_rx_irq;
        }

        mod_timer(&lp->media_check_timer, jiffies + 1);
out:
        return ret;

err_free_rx_irq:
        free_irq(lp->rx_irq, dev);
err_release:
        korina_free_ring(dev);
        goto out;
}

static int korina_close(struct net_device *dev)
{
        struct korina_private *lp = netdev_priv(dev);
        u32 tmp;

        timer_delete(&lp->media_check_timer);

        /* Disable interrupts */
        disable_irq(lp->rx_irq);
        disable_irq(lp->tx_irq);

        korina_abort_tx(dev);
        tmp = readl(&lp->tx_dma_regs->dmasm);
        tmp = tmp | DMA_STAT_FINI | DMA_STAT_ERR;
        writel(tmp, &lp->tx_dma_regs->dmasm);

        korina_abort_rx(dev);
        tmp = readl(&lp->rx_dma_regs->dmasm);
        tmp = tmp | DMA_STAT_DONE | DMA_STAT_HALT | DMA_STAT_ERR;
        writel(tmp, &lp->rx_dma_regs->dmasm);

        napi_disable(&lp->napi);

        cancel_work_sync(&lp->restart_task);

        korina_free_ring(dev);

        free_irq(lp->rx_irq, dev);
        free_irq(lp->tx_irq, dev);

        return 0;
}

static const struct net_device_ops korina_netdev_ops = {
        .ndo_open               = korina_open,
        .ndo_stop               = korina_close,
        .ndo_start_xmit         = korina_send_packet,
        .ndo_set_rx_mode        = korina_multicast_list,
        .ndo_tx_timeout         = korina_tx_timeout,
        .ndo_eth_ioctl          = korina_ioctl,
        .ndo_validate_addr      = eth_validate_addr,
        .ndo_set_mac_address    = eth_mac_addr,
#ifdef CONFIG_NET_POLL_CONTROLLER
        .ndo_poll_controller    = korina_poll_controller,
#endif
};

static int korina_probe(struct platform_device *pdev)
{
        u8 *mac_addr = dev_get_platdata(&pdev->dev);
        struct korina_private *lp;
        struct net_device *dev;
        struct clk *clk;
        void __iomem *p;
        int rc;

        dev = devm_alloc_etherdev(&pdev->dev, sizeof(struct korina_private));
        if (!dev)
                return -ENOMEM;

        SET_NETDEV_DEV(dev, &pdev->dev);
        lp = netdev_priv(dev);

        if (mac_addr)
                eth_hw_addr_set(dev, mac_addr);
        else if (of_get_ethdev_address(pdev->dev.of_node, dev) < 0)
                eth_hw_addr_random(dev);

        clk = devm_clk_get_optional_enabled(&pdev->dev, "mdioclk");
        if (IS_ERR(clk))
                return PTR_ERR(clk);
        if (clk) {
                lp->mii_clock_freq = clk_get_rate(clk);
        } else {
                lp->mii_clock_freq = 200000000; /* max possible input clk */
        }

        lp->rx_irq = platform_get_irq_byname(pdev, "rx");
        lp->tx_irq = platform_get_irq_byname(pdev, "tx");

        p = devm_platform_ioremap_resource_byname(pdev, "emac");
        if (IS_ERR(p)) {
                printk(KERN_ERR DRV_NAME ": cannot remap registers\n");
                return PTR_ERR(p);
        }
        lp->eth_regs = p;

        p = devm_platform_ioremap_resource_byname(pdev, "dma_rx");
        if (IS_ERR(p)) {
                printk(KERN_ERR DRV_NAME ": cannot remap Rx DMA registers\n");
                return PTR_ERR(p);
        }
        lp->rx_dma_regs = p;

        p = devm_platform_ioremap_resource_byname(pdev, "dma_tx");
        if (IS_ERR(p)) {
                printk(KERN_ERR DRV_NAME ": cannot remap Tx DMA registers\n");
                return PTR_ERR(p);
        }
        lp->tx_dma_regs = p;

        lp->td_ring = dmam_alloc_coherent(&pdev->dev, TD_RING_SIZE,
                                          &lp->td_dma, GFP_KERNEL);
        if (!lp->td_ring)
                return -ENOMEM;

        lp->rd_ring = dmam_alloc_coherent(&pdev->dev, RD_RING_SIZE,
                                          &lp->rd_dma, GFP_KERNEL);
        if (!lp->rd_ring)
                return -ENOMEM;

        spin_lock_init(&lp->lock);
        /* just use the rx dma irq */
        dev->irq = lp->rx_irq;
        lp->dev = dev;
        lp->dmadev = &pdev->dev;

        dev->netdev_ops = &korina_netdev_ops;
        dev->ethtool_ops = &netdev_ethtool_ops;
        dev->watchdog_timeo = TX_TIMEOUT;
        netif_napi_add(dev, &lp->napi, korina_poll);

        lp->mii_if.dev = dev;
        lp->mii_if.mdio_read = korina_mdio_read;
        lp->mii_if.mdio_write = korina_mdio_write;
        lp->mii_if.phy_id = 1;
        lp->mii_if.phy_id_mask = 0x1f;
        lp->mii_if.reg_num_mask = 0x1f;

        platform_set_drvdata(pdev, dev);

        rc = register_netdev(dev);
        if (rc < 0) {
                printk(KERN_ERR DRV_NAME
                        ": cannot register net device: %d\n", rc);
                return rc;
        }
        timer_setup(&lp->media_check_timer, korina_poll_media, 0);

        INIT_WORK(&lp->restart_task, korina_restart_task);

        printk(KERN_INFO "%s: " DRV_NAME "-" DRV_VERSION " " DRV_RELDATE "\n",
                        dev->name);
        return rc;
}

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

        unregister_netdev(dev);
}

#ifdef CONFIG_OF
static const struct of_device_id korina_match[] = {
        {
                .compatible = "idt,3243x-emac",
        },
        { }
};
MODULE_DEVICE_TABLE(of, korina_match);
#endif

static struct platform_driver korina_driver = {
        .driver = {
                .name = "korina",
                .of_match_table = of_match_ptr(korina_match),
        },
        .probe = korina_probe,
        .remove = korina_remove,
};

module_platform_driver(korina_driver);

MODULE_AUTHOR("Philip Rischel <rischelp@idt.com>");
MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
MODULE_AUTHOR("Roman Yeryomin <roman@advem.lv>");
MODULE_DESCRIPTION("IDT RC32434 (Korina) Ethernet driver");
MODULE_LICENSE("GPL");