/*
 * Ethernet driver for the WIZnet W5100 chip.
 *
 * Copyright (C) 2006-2008 WIZnet Co.,Ltd.
 * Copyright (C) 2012 Mike Sinkovsky <msink@permonline.ru>
 *
 * Licensed under the GPL-2 or later.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/platform_device.h>
#include <linux/platform_data/wiznet.h>
#include <linux/ethtool.h>
#include <linux/skbuff.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/gpio.h>

#include "w5100.h"

#define DRV_NAME        "w5100"
#define DRV_VERSION     "2012-04-04"

MODULE_DESCRIPTION("WIZnet W5100 Ethernet driver v"DRV_VERSION);
MODULE_AUTHOR("Mike Sinkovsky <msink@permonline.ru>");
MODULE_ALIAS("platform:"DRV_NAME);
MODULE_LICENSE("GPL");

/*
 * W5100/W5200/W5500 common registers
 */
#define W5100_COMMON_REGS       0x0000
#define W5100_MR                0x0000 /* Mode Register */
#define   MR_RST                  0x80 /* S/W reset */
#define   MR_PB                   0x10 /* Ping block */
#define   MR_AI                   0x02 /* Address Auto-Increment */
#define   MR_IND                  0x01 /* Indirect mode */
#define W5100_SHAR              0x0009 /* Source MAC address */
#define W5100_IR                0x0015 /* Interrupt Register */
#define W5100_COMMON_REGS_LEN   0x0040

#define W5100_Sn_MR             0x0000 /* Sn Mode Register */
#define W5100_Sn_CR             0x0001 /* Sn Command Register */
#define W5100_Sn_IR             0x0002 /* Sn Interrupt Register */
#define W5100_Sn_SR             0x0003 /* Sn Status Register */
#define W5100_Sn_TX_FSR         0x0020 /* Sn Transmit free memory size */
#define W5100_Sn_TX_RD          0x0022 /* Sn Transmit memory read pointer */
#define W5100_Sn_TX_WR          0x0024 /* Sn Transmit memory write pointer */
#define W5100_Sn_RX_RSR         0x0026 /* Sn Receive free memory size */
#define W5100_Sn_RX_RD          0x0028 /* Sn Receive memory read pointer */

#define S0_REGS(priv)           ((priv)->s0_regs)

#define W5100_S0_MR(priv)       (S0_REGS(priv) + W5100_Sn_MR)
#define   S0_MR_MACRAW            0x04 /* MAC RAW mode */
#define   S0_MR_MF                0x40 /* MAC Filter for W5100 and W5200 */
#define   W5500_S0_MR_MF          0x80 /* MAC Filter for W5500 */
#define W5100_S0_CR(priv)       (S0_REGS(priv) + W5100_Sn_CR)
#define   S0_CR_OPEN              0x01 /* OPEN command */
#define   S0_CR_CLOSE             0x10 /* CLOSE command */
#define   S0_CR_SEND              0x20 /* SEND command */
#define   S0_CR_RECV              0x40 /* RECV command */
#define W5100_S0_IR(priv)       (S0_REGS(priv) + W5100_Sn_IR)
#define   S0_IR_SENDOK            0x10 /* complete sending */
#define   S0_IR_RECV              0x04 /* receiving data */
#define W5100_S0_SR(priv)       (S0_REGS(priv) + W5100_Sn_SR)
#define   S0_SR_MACRAW            0x42 /* mac raw mode */
#define W5100_S0_TX_FSR(priv)   (S0_REGS(priv) + W5100_Sn_TX_FSR)
#define W5100_S0_TX_RD(priv)    (S0_REGS(priv) + W5100_Sn_TX_RD)
#define W5100_S0_TX_WR(priv)    (S0_REGS(priv) + W5100_Sn_TX_WR)
#define W5100_S0_RX_RSR(priv)   (S0_REGS(priv) + W5100_Sn_RX_RSR)
#define W5100_S0_RX_RD(priv)    (S0_REGS(priv) + W5100_Sn_RX_RD)

#define W5100_S0_REGS_LEN       0x0040

/*
 * W5100 and W5200 common registers
 */
#define W5100_IMR               0x0016 /* Interrupt Mask Register */
#define   IR_S0                   0x01 /* S0 interrupt */
#define W5100_RTR               0x0017 /* Retry Time-value Register */
#define   RTR_DEFAULT             2000 /* =0x07d0 (2000) */

/*
 * W5100 specific register and memory
 */
#define W5100_RMSR              0x001a /* Receive Memory Size */
#define W5100_TMSR              0x001b /* Transmit Memory Size */

#define W5100_S0_REGS           0x0400

#define W5100_TX_MEM_START      0x4000
#define W5100_TX_MEM_SIZE       0x2000
#define W5100_RX_MEM_START      0x6000
#define W5100_RX_MEM_SIZE       0x2000

/*
 * W5200 specific register and memory
 */
#define W5200_S0_REGS           0x4000

#define W5200_Sn_RXMEM_SIZE(n)  (0x401e + (n) * 0x0100) /* Sn RX Memory Size */
#define W5200_Sn_TXMEM_SIZE(n)  (0x401f + (n) * 0x0100) /* Sn TX Memory Size */

#define W5200_TX_MEM_START      0x8000
#define W5200_TX_MEM_SIZE       0x4000
#define W5200_RX_MEM_START      0xc000
#define W5200_RX_MEM_SIZE       0x4000

/*
 * W5500 specific register and memory
 *
 * W5500 register and memory are organized by multiple blocks.  Each one is
 * selected by 16bits offset address and 5bits block select bits.  So we
 * encode it into 32bits address. (lower 16bits is offset address and
 * upper 16bits is block select bits)
 */
#define W5500_SIMR              0x0018 /* Socket Interrupt Mask Register */
#define W5500_RTR               0x0019 /* Retry Time-value Register */

#define W5500_S0_REGS           0x10000

#define W5500_Sn_RXMEM_SIZE(n)  \
                (0x1001e + (n) * 0x40000) /* Sn RX Memory Size */
#define W5500_Sn_TXMEM_SIZE(n)  \
                (0x1001f + (n) * 0x40000) /* Sn TX Memory Size */

#define W5500_TX_MEM_START      0x20000
#define W5500_TX_MEM_SIZE       0x04000
#define W5500_RX_MEM_START      0x30000
#define W5500_RX_MEM_SIZE       0x04000

/*
 * Device driver private data structure
 */

struct w5100_priv {
        const struct w5100_ops *ops;

        /* Socket 0 register offset address */
        u32 s0_regs;
        /* Socket 0 TX buffer offset address and size */
        u32 s0_tx_buf;
        u16 s0_tx_buf_size;
        /* Socket 0 RX buffer offset address and size */
        u32 s0_rx_buf;
        u16 s0_rx_buf_size;

        int irq;
        int link_irq;
        int link_gpio;

        struct napi_struct napi;
        struct net_device *ndev;
        bool promisc;
        u32 msg_enable;

        struct workqueue_struct *xfer_wq;
        struct work_struct rx_work;
        struct sk_buff *tx_skb;
        struct work_struct tx_work;
        struct work_struct setrx_work;
        struct work_struct restart_work;
};

/************************************************************************
 *
 *  Lowlevel I/O functions
 *
 ***********************************************************************/

struct w5100_mmio_priv {
        void __iomem *base;
        /* Serialize access in indirect address mode */
        spinlock_t reg_lock;
};

static inline struct w5100_mmio_priv *w5100_mmio_priv(struct net_device *dev)
{
        return w5100_ops_priv(dev);
}

static inline void __iomem *w5100_mmio(struct net_device *ndev)
{
        struct w5100_mmio_priv *mmio_priv = w5100_mmio_priv(ndev);

        return mmio_priv->base;
}

/*
 * In direct address mode host system can directly access W5100 registers
 * after mapping to Memory-Mapped I/O space.
 *
 * 0x8000 bytes are required for memory space.
 */
static inline int w5100_read_direct(struct net_device *ndev, u32 addr)
{
        return ioread8(w5100_mmio(ndev) + (addr << CONFIG_WIZNET_BUS_SHIFT));
}

static inline int __w5100_write_direct(struct net_device *ndev, u32 addr,
                                       u8 data)
{
        iowrite8(data, w5100_mmio(ndev) + (addr << CONFIG_WIZNET_BUS_SHIFT));

        return 0;
}

static inline int w5100_write_direct(struct net_device *ndev, u32 addr, u8 data)
{
        __w5100_write_direct(ndev, addr, data);
        mmiowb();

        return 0;
}

static int w5100_read16_direct(struct net_device *ndev, u32 addr)
{
        u16 data;
        data  = w5100_read_direct(ndev, addr) << 8;
        data |= w5100_read_direct(ndev, addr + 1);
        return data;
}

static int w5100_write16_direct(struct net_device *ndev, u32 addr, u16 data)
{
        __w5100_write_direct(ndev, addr, data >> 8);
        __w5100_write_direct(ndev, addr + 1, data);
        mmiowb();

        return 0;
}

static int w5100_readbulk_direct(struct net_device *ndev, u32 addr, u8 *buf,
                                 int len)
{
        int i;

        for (i = 0; i < len; i++, addr++)
                *buf++ = w5100_read_direct(ndev, addr);

        return 0;
}

static int w5100_writebulk_direct(struct net_device *ndev, u32 addr,
                                  const u8 *buf, int len)
{
        int i;

        for (i = 0; i < len; i++, addr++)
                __w5100_write_direct(ndev, addr, *buf++);

        mmiowb();

        return 0;
}

static int w5100_mmio_init(struct net_device *ndev)
{
        struct platform_device *pdev = to_platform_device(ndev->dev.parent);
        struct w5100_priv *priv = netdev_priv(ndev);
        struct w5100_mmio_priv *mmio_priv = w5100_mmio_priv(ndev);
        struct resource *mem;

        spin_lock_init(&mmio_priv->reg_lock);

        mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        mmio_priv->base = devm_ioremap_resource(&pdev->dev, mem);
        if (IS_ERR(mmio_priv->base))
                return PTR_ERR(mmio_priv->base);

        netdev_info(ndev, "at 0x%llx irq %d\n", (u64)mem->start, priv->irq);

        return 0;
}

static const struct w5100_ops w5100_mmio_direct_ops = {
        .chip_id = W5100,
        .read = w5100_read_direct,
        .write = w5100_write_direct,
        .read16 = w5100_read16_direct,
        .write16 = w5100_write16_direct,
        .readbulk = w5100_readbulk_direct,
        .writebulk = w5100_writebulk_direct,
        .init = w5100_mmio_init,
};

/*
 * In indirect address mode host system indirectly accesses registers by
 * using Indirect Mode Address Register (IDM_AR) and Indirect Mode Data
 * Register (IDM_DR), which are directly mapped to Memory-Mapped I/O space.
 * Mode Register (MR) is directly accessible.
 *
 * Only 0x04 bytes are required for memory space.
 */
#define W5100_IDM_AR            0x01   /* Indirect Mode Address Register */
#define W5100_IDM_DR            0x03   /* Indirect Mode Data Register */

static int w5100_read_indirect(struct net_device *ndev, u32 addr)
{
        struct w5100_mmio_priv *mmio_priv = w5100_mmio_priv(ndev);
        unsigned long flags;
        u8 data;

        spin_lock_irqsave(&mmio_priv->reg_lock, flags);
        w5100_write16_direct(ndev, W5100_IDM_AR, addr);
        data = w5100_read_direct(ndev, W5100_IDM_DR);
        spin_unlock_irqrestore(&mmio_priv->reg_lock, flags);

        return data;
}

static int w5100_write_indirect(struct net_device *ndev, u32 addr, u8 data)
{
        struct w5100_mmio_priv *mmio_priv = w5100_mmio_priv(ndev);
        unsigned long flags;

        spin_lock_irqsave(&mmio_priv->reg_lock, flags);
        w5100_write16_direct(ndev, W5100_IDM_AR, addr);
        w5100_write_direct(ndev, W5100_IDM_DR, data);
        spin_unlock_irqrestore(&mmio_priv->reg_lock, flags);

        return 0;
}

static int w5100_read16_indirect(struct net_device *ndev, u32 addr)
{
        struct w5100_mmio_priv *mmio_priv = w5100_mmio_priv(ndev);
        unsigned long flags;
        u16 data;

        spin_lock_irqsave(&mmio_priv->reg_lock, flags);
        w5100_write16_direct(ndev, W5100_IDM_AR, addr);
        data  = w5100_read_direct(ndev, W5100_IDM_DR) << 8;
        data |= w5100_read_direct(ndev, W5100_IDM_DR);
        spin_unlock_irqrestore(&mmio_priv->reg_lock, flags);

        return data;
}

static int w5100_write16_indirect(struct net_device *ndev, u32 addr, u16 data)
{
        struct w5100_mmio_priv *mmio_priv = w5100_mmio_priv(ndev);
        unsigned long flags;

        spin_lock_irqsave(&mmio_priv->reg_lock, flags);
        w5100_write16_direct(ndev, W5100_IDM_AR, addr);
        __w5100_write_direct(ndev, W5100_IDM_DR, data >> 8);
        w5100_write_direct(ndev, W5100_IDM_DR, data);
        spin_unlock_irqrestore(&mmio_priv->reg_lock, flags);

        return 0;
}

static int w5100_readbulk_indirect(struct net_device *ndev, u32 addr, u8 *buf,
                                   int len)
{
        struct w5100_mmio_priv *mmio_priv = w5100_mmio_priv(ndev);
        unsigned long flags;
        int i;

        spin_lock_irqsave(&mmio_priv->reg_lock, flags);
        w5100_write16_direct(ndev, W5100_IDM_AR, addr);

        for (i = 0; i < len; i++)
                *buf++ = w5100_read_direct(ndev, W5100_IDM_DR);

        mmiowb();
        spin_unlock_irqrestore(&mmio_priv->reg_lock, flags);

        return 0;
}

static int w5100_writebulk_indirect(struct net_device *ndev, u32 addr,
                                    const u8 *buf, int len)
{
        struct w5100_mmio_priv *mmio_priv = w5100_mmio_priv(ndev);
        unsigned long flags;
        int i;

        spin_lock_irqsave(&mmio_priv->reg_lock, flags);
        w5100_write16_direct(ndev, W5100_IDM_AR, addr);

        for (i = 0; i < len; i++)
                __w5100_write_direct(ndev, W5100_IDM_DR, *buf++);

        mmiowb();
        spin_unlock_irqrestore(&mmio_priv->reg_lock, flags);

        return 0;
}

static int w5100_reset_indirect(struct net_device *ndev)
{
        w5100_write_direct(ndev, W5100_MR, MR_RST);
        mdelay(5);
        w5100_write_direct(ndev, W5100_MR, MR_PB | MR_AI | MR_IND);

        return 0;
}

static const struct w5100_ops w5100_mmio_indirect_ops = {
        .chip_id = W5100,
        .read = w5100_read_indirect,
        .write = w5100_write_indirect,
        .read16 = w5100_read16_indirect,
        .write16 = w5100_write16_indirect,
        .readbulk = w5100_readbulk_indirect,
        .writebulk = w5100_writebulk_indirect,
        .init = w5100_mmio_init,
        .reset = w5100_reset_indirect,
};

#if defined(CONFIG_WIZNET_BUS_DIRECT)

static int w5100_read(struct w5100_priv *priv, u32 addr)
{
        return w5100_read_direct(priv->ndev, addr);
}

static int w5100_write(struct w5100_priv *priv, u32 addr, u8 data)
{
        return w5100_write_direct(priv->ndev, addr, data);
}

static int w5100_read16(struct w5100_priv *priv, u32 addr)
{
        return w5100_read16_direct(priv->ndev, addr);
}

static int w5100_write16(struct w5100_priv *priv, u32 addr, u16 data)
{
        return w5100_write16_direct(priv->ndev, addr, data);
}

static int w5100_readbulk(struct w5100_priv *priv, u32 addr, u8 *buf, int len)
{
        return w5100_readbulk_direct(priv->ndev, addr, buf, len);
}

static int w5100_writebulk(struct w5100_priv *priv, u32 addr, const u8 *buf,
                           int len)
{
        return w5100_writebulk_direct(priv->ndev, addr, buf, len);
}

#elif defined(CONFIG_WIZNET_BUS_INDIRECT)

static int w5100_read(struct w5100_priv *priv, u32 addr)
{
        return w5100_read_indirect(priv->ndev, addr);
}

static int w5100_write(struct w5100_priv *priv, u32 addr, u8 data)
{
        return w5100_write_indirect(priv->ndev, addr, data);
}

static int w5100_read16(struct w5100_priv *priv, u32 addr)
{
        return w5100_read16_indirect(priv->ndev, addr);
}

static int w5100_write16(struct w5100_priv *priv, u32 addr, u16 data)
{
        return w5100_write16_indirect(priv->ndev, addr, data);
}

static int w5100_readbulk(struct w5100_priv *priv, u32 addr, u8 *buf, int len)
{
        return w5100_readbulk_indirect(priv->ndev, addr, buf, len);
}

static int w5100_writebulk(struct w5100_priv *priv, u32 addr, const u8 *buf,
                           int len)
{
        return w5100_writebulk_indirect(priv->ndev, addr, buf, len);
}

#else /* CONFIG_WIZNET_BUS_ANY */

static int w5100_read(struct w5100_priv *priv, u32 addr)
{
        return priv->ops->read(priv->ndev, addr);
}

static int w5100_write(struct w5100_priv *priv, u32 addr, u8 data)
{
        return priv->ops->write(priv->ndev, addr, data);
}

static int w5100_read16(struct w5100_priv *priv, u32 addr)
{
        return priv->ops->read16(priv->ndev, addr);
}

static int w5100_write16(struct w5100_priv *priv, u32 addr, u16 data)
{
        return priv->ops->write16(priv->ndev, addr, data);
}

static int w5100_readbulk(struct w5100_priv *priv, u32 addr, u8 *buf, int len)
{
        return priv->ops->readbulk(priv->ndev, addr, buf, len);
}

static int w5100_writebulk(struct w5100_priv *priv, u32 addr, const u8 *buf,
                           int len)
{
        return priv->ops->writebulk(priv->ndev, addr, buf, len);
}

#endif

static int w5100_readbuf(struct w5100_priv *priv, u16 offset, u8 *buf, int len)
{
        u32 addr;
        int remain = 0;
        int ret;
        const u32 mem_start = priv->s0_rx_buf;
        const u16 mem_size = priv->s0_rx_buf_size;

        offset %= mem_size;
        addr = mem_start + offset;

        if (offset + len > mem_size) {
                remain = (offset + len) % mem_size;
                len = mem_size - offset;
        }

        ret = w5100_readbulk(priv, addr, buf, len);
        if (ret || !remain)
                return ret;

        return w5100_readbulk(priv, mem_start, buf + len, remain);
}

static int w5100_writebuf(struct w5100_priv *priv, u16 offset, const u8 *buf,
                          int len)
{
        u32 addr;
        int ret;
        int remain = 0;
        const u32 mem_start = priv->s0_tx_buf;
        const u16 mem_size = priv->s0_tx_buf_size;

        offset %= mem_size;
        addr = mem_start + offset;

        if (offset + len > mem_size) {
                remain = (offset + len) % mem_size;
                len = mem_size - offset;
        }

        ret = w5100_writebulk(priv, addr, buf, len);
        if (ret || !remain)
                return ret;

        return w5100_writebulk(priv, mem_start, buf + len, remain);
}

static int w5100_reset(struct w5100_priv *priv)
{
        if (priv->ops->reset)
                return priv->ops->reset(priv->ndev);

        w5100_write(priv, W5100_MR, MR_RST);
        mdelay(5);
        w5100_write(priv, W5100_MR, MR_PB);

        return 0;
}

static int w5100_command(struct w5100_priv *priv, u16 cmd)
{
        unsigned long timeout;

        w5100_write(priv, W5100_S0_CR(priv), cmd);

        timeout = jiffies + msecs_to_jiffies(100);

        while (w5100_read(priv, W5100_S0_CR(priv)) != 0) {
                if (time_after(jiffies, timeout))
                        return -EIO;
                cpu_relax();
        }

        return 0;
}

static void w5100_write_macaddr(struct w5100_priv *priv)
{
        struct net_device *ndev = priv->ndev;

        w5100_writebulk(priv, W5100_SHAR, ndev->dev_addr, ETH_ALEN);
}

static void w5100_socket_intr_mask(struct w5100_priv *priv, u8 mask)
{
        u32 imr;

        if (priv->ops->chip_id == W5500)
                imr = W5500_SIMR;
        else
                imr = W5100_IMR;

        w5100_write(priv, imr, mask);
}

static void w5100_enable_intr(struct w5100_priv *priv)
{
        w5100_socket_intr_mask(priv, IR_S0);
}

static void w5100_disable_intr(struct w5100_priv *priv)
{
        w5100_socket_intr_mask(priv, 0);
}

static void w5100_memory_configure(struct w5100_priv *priv)
{
        /* Configure 16K of internal memory
         * as 8K RX buffer and 8K TX buffer
         */
        w5100_write(priv, W5100_RMSR, 0x03);
        w5100_write(priv, W5100_TMSR, 0x03);
}

static void w5200_memory_configure(struct w5100_priv *priv)
{
        int i;

        /* Configure internal RX memory as 16K RX buffer and
         * internal TX memory as 16K TX buffer
         */
        w5100_write(priv, W5200_Sn_RXMEM_SIZE(0), 0x10);
        w5100_write(priv, W5200_Sn_TXMEM_SIZE(0), 0x10);

        for (i = 1; i < 8; i++) {
                w5100_write(priv, W5200_Sn_RXMEM_SIZE(i), 0);
                w5100_write(priv, W5200_Sn_TXMEM_SIZE(i), 0);
        }
}

static void w5500_memory_configure(struct w5100_priv *priv)
{
        int i;

        /* Configure internal RX memory as 16K RX buffer and
         * internal TX memory as 16K TX buffer
         */
        w5100_write(priv, W5500_Sn_RXMEM_SIZE(0), 0x10);
        w5100_write(priv, W5500_Sn_TXMEM_SIZE(0), 0x10);

        for (i = 1; i < 8; i++) {
                w5100_write(priv, W5500_Sn_RXMEM_SIZE(i), 0);
                w5100_write(priv, W5500_Sn_TXMEM_SIZE(i), 0);
        }
}

static int w5100_hw_reset(struct w5100_priv *priv)
{
        u32 rtr;

        w5100_reset(priv);

        w5100_disable_intr(priv);
        w5100_write_macaddr(priv);

        switch (priv->ops->chip_id) {
        case W5100:
                w5100_memory_configure(priv);
                rtr = W5100_RTR;
                break;
        case W5200:
                w5200_memory_configure(priv);
                rtr = W5100_RTR;
                break;
        case W5500:
                w5500_memory_configure(priv);
                rtr = W5500_RTR;
                break;
        default:
                return -EINVAL;
        }

        if (w5100_read16(priv, rtr) != RTR_DEFAULT)
                return -ENODEV;

        return 0;
}

static void w5100_hw_start(struct w5100_priv *priv)
{
        u8 mode = S0_MR_MACRAW;

        if (!priv->promisc) {
                if (priv->ops->chip_id == W5500)
                        mode |= W5500_S0_MR_MF;
                else
                        mode |= S0_MR_MF;
        }

        w5100_write(priv, W5100_S0_MR(priv), mode);
        w5100_command(priv, S0_CR_OPEN);
        w5100_enable_intr(priv);
}

static void w5100_hw_close(struct w5100_priv *priv)
{
        w5100_disable_intr(priv);
        w5100_command(priv, S0_CR_CLOSE);
}

/***********************************************************************
 *
 *   Device driver functions / callbacks
 *
 ***********************************************************************/

static void w5100_get_drvinfo(struct net_device *ndev,
                              struct ethtool_drvinfo *info)
{
        strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
        strlcpy(info->version, DRV_VERSION, sizeof(info->version));
        strlcpy(info->bus_info, dev_name(ndev->dev.parent),
                sizeof(info->bus_info));
}

static u32 w5100_get_link(struct net_device *ndev)
{
        struct w5100_priv *priv = netdev_priv(ndev);

        if (gpio_is_valid(priv->link_gpio))
                return !!gpio_get_value(priv->link_gpio);

        return 1;
}

static u32 w5100_get_msglevel(struct net_device *ndev)
{
        struct w5100_priv *priv = netdev_priv(ndev);

        return priv->msg_enable;
}

static void w5100_set_msglevel(struct net_device *ndev, u32 value)
{
        struct w5100_priv *priv = netdev_priv(ndev);

        priv->msg_enable = value;
}

static int w5100_get_regs_len(struct net_device *ndev)
{
        return W5100_COMMON_REGS_LEN + W5100_S0_REGS_LEN;
}

static void w5100_get_regs(struct net_device *ndev,
                           struct ethtool_regs *regs, void *buf)
{
        struct w5100_priv *priv = netdev_priv(ndev);

        regs->version = 1;
        w5100_readbulk(priv, W5100_COMMON_REGS, buf, W5100_COMMON_REGS_LEN);
        buf += W5100_COMMON_REGS_LEN;
        w5100_readbulk(priv, S0_REGS(priv), buf, W5100_S0_REGS_LEN);
}

static void w5100_restart(struct net_device *ndev)
{
        struct w5100_priv *priv = netdev_priv(ndev);

        netif_stop_queue(ndev);
        w5100_hw_reset(priv);
        w5100_hw_start(priv);
        ndev->stats.tx_errors++;
        netif_trans_update(ndev);
        netif_wake_queue(ndev);
}

static void w5100_restart_work(struct work_struct *work)
{
        struct w5100_priv *priv = container_of(work, struct w5100_priv,
                                               restart_work);

        w5100_restart(priv->ndev);
}

static void w5100_tx_timeout(struct net_device *ndev)
{
        struct w5100_priv *priv = netdev_priv(ndev);

        if (priv->ops->may_sleep)
                schedule_work(&priv->restart_work);
        else
                w5100_restart(ndev);
}

static void w5100_tx_skb(struct net_device *ndev, struct sk_buff *skb)
{
        struct w5100_priv *priv = netdev_priv(ndev);
        u16 offset;

        offset = w5100_read16(priv, W5100_S0_TX_WR(priv));
        w5100_writebuf(priv, offset, skb->data, skb->len);
        w5100_write16(priv, W5100_S0_TX_WR(priv), offset + skb->len);
        ndev->stats.tx_bytes += skb->len;
        ndev->stats.tx_packets++;
        dev_kfree_skb(skb);

        w5100_command(priv, S0_CR_SEND);
}

static void w5100_tx_work(struct work_struct *work)
{
        struct w5100_priv *priv = container_of(work, struct w5100_priv,
                                               tx_work);
        struct sk_buff *skb = priv->tx_skb;

        priv->tx_skb = NULL;

        if (WARN_ON(!skb))
                return;
        w5100_tx_skb(priv->ndev, skb);
}

static int w5100_start_tx(struct sk_buff *skb, struct net_device *ndev)
{
        struct w5100_priv *priv = netdev_priv(ndev);

        netif_stop_queue(ndev);

        if (priv->ops->may_sleep) {
                WARN_ON(priv->tx_skb);
                priv->tx_skb = skb;
                queue_work(priv->xfer_wq, &priv->tx_work);
        } else {
                w5100_tx_skb(ndev, skb);
        }

        return NETDEV_TX_OK;
}

static struct sk_buff *w5100_rx_skb(struct net_device *ndev)
{
        struct w5100_priv *priv = netdev_priv(ndev);
        struct sk_buff *skb;
        u16 rx_len;
        u16 offset;
        u8 header[2];
        u16 rx_buf_len = w5100_read16(priv, W5100_S0_RX_RSR(priv));

        if (rx_buf_len == 0)
                return NULL;

        offset = w5100_read16(priv, W5100_S0_RX_RD(priv));
        w5100_readbuf(priv, offset, header, 2);
        rx_len = get_unaligned_be16(header) - 2;

        skb = netdev_alloc_skb_ip_align(ndev, rx_len);
        if (unlikely(!skb)) {
                w5100_write16(priv, W5100_S0_RX_RD(priv), offset + rx_buf_len);
                w5100_command(priv, S0_CR_RECV);
                ndev->stats.rx_dropped++;
                return NULL;
        }

        skb_put(skb, rx_len);
        w5100_readbuf(priv, offset + 2, skb->data, rx_len);
        w5100_write16(priv, W5100_S0_RX_RD(priv), offset + 2 + rx_len);
        w5100_command(priv, S0_CR_RECV);
        skb->protocol = eth_type_trans(skb, ndev);

        ndev->stats.rx_packets++;
        ndev->stats.rx_bytes += rx_len;

        return skb;
}

static void w5100_rx_work(struct work_struct *work)
{
        struct w5100_priv *priv = container_of(work, struct w5100_priv,
                                               rx_work);
        struct sk_buff *skb;

        while ((skb = w5100_rx_skb(priv->ndev)))
                netif_rx_ni(skb);

        w5100_enable_intr(priv);
}

static int w5100_napi_poll(struct napi_struct *napi, int budget)
{
        struct w5100_priv *priv = container_of(napi, struct w5100_priv, napi);
        int rx_count;

        for (rx_count = 0; rx_count < budget; rx_count++) {
                struct sk_buff *skb = w5100_rx_skb(priv->ndev);

                if (skb)
                        netif_receive_skb(skb);
                else
                        break;
        }

        if (rx_count < budget) {
                napi_complete_done(napi, rx_count);
                w5100_enable_intr(priv);
        }

        return rx_count;
}

static irqreturn_t w5100_interrupt(int irq, void *ndev_instance)
{
        struct net_device *ndev = ndev_instance;
        struct w5100_priv *priv = netdev_priv(ndev);

        int ir = w5100_read(priv, W5100_S0_IR(priv));
        if (!ir)
                return IRQ_NONE;
        w5100_write(priv, W5100_S0_IR(priv), ir);

        if (ir & S0_IR_SENDOK) {
                netif_dbg(priv, tx_done, ndev, "tx done\n");
                netif_wake_queue(ndev);
        }

        if (ir & S0_IR_RECV) {
                w5100_disable_intr(priv);

                if (priv->ops->may_sleep)
                        queue_work(priv->xfer_wq, &priv->rx_work);
                else if (napi_schedule_prep(&priv->napi))
                        __napi_schedule(&priv->napi);
        }

        return IRQ_HANDLED;
}

static irqreturn_t w5100_detect_link(int irq, void *ndev_instance)
{
        struct net_device *ndev = ndev_instance;
        struct w5100_priv *priv = netdev_priv(ndev);

        if (netif_running(ndev)) {
                if (gpio_get_value(priv->link_gpio) != 0) {
                        netif_info(priv, link, ndev, "link is up\n");
                        netif_carrier_on(ndev);
                } else {
                        netif_info(priv, link, ndev, "link is down\n");
                        netif_carrier_off(ndev);
                }
        }

        return IRQ_HANDLED;
}

static void w5100_setrx_work(struct work_struct *work)
{
        struct w5100_priv *priv = container_of(work, struct w5100_priv,
                                               setrx_work);

        w5100_hw_start(priv);
}

static void w5100_set_rx_mode(struct net_device *ndev)
{
        struct w5100_priv *priv = netdev_priv(ndev);
        bool set_promisc = (ndev->flags & IFF_PROMISC) != 0;

        if (priv->promisc != set_promisc) {
                priv->promisc = set_promisc;

                if (priv->ops->may_sleep)
                        schedule_work(&priv->setrx_work);
                else
                        w5100_hw_start(priv);
        }
}

static int w5100_set_macaddr(struct net_device *ndev, void *addr)
{
        struct w5100_priv *priv = netdev_priv(ndev);
        struct sockaddr *sock_addr = addr;

        if (!is_valid_ether_addr(sock_addr->sa_data))
                return -EADDRNOTAVAIL;
        memcpy(ndev->dev_addr, sock_addr->sa_data, ETH_ALEN);

        w5100_write_macaddr(priv);
        return 0;
}

static int w5100_open(struct net_device *ndev)
{
        struct w5100_priv *priv = netdev_priv(ndev);

        netif_info(priv, ifup, ndev, "enabling\n");
        w5100_hw_start(priv);
        napi_enable(&priv->napi);
        netif_start_queue(ndev);
        if (!gpio_is_valid(priv->link_gpio) ||
            gpio_get_value(priv->link_gpio) != 0)
                netif_carrier_on(ndev);
        return 0;
}

static int w5100_stop(struct net_device *ndev)
{
        struct w5100_priv *priv = netdev_priv(ndev);

        netif_info(priv, ifdown, ndev, "shutting down\n");
        w5100_hw_close(priv);
        netif_carrier_off(ndev);
        netif_stop_queue(ndev);
        napi_disable(&priv->napi);
        return 0;
}

static const struct ethtool_ops w5100_ethtool_ops = {
        .get_drvinfo            = w5100_get_drvinfo,
        .get_msglevel           = w5100_get_msglevel,
        .set_msglevel           = w5100_set_msglevel,
        .get_link               = w5100_get_link,
        .get_regs_len           = w5100_get_regs_len,
        .get_regs               = w5100_get_regs,
};

static const struct net_device_ops w5100_netdev_ops = {
        .ndo_open               = w5100_open,
        .ndo_stop               = w5100_stop,
        .ndo_start_xmit         = w5100_start_tx,
        .ndo_tx_timeout         = w5100_tx_timeout,
        .ndo_set_rx_mode        = w5100_set_rx_mode,
        .ndo_set_mac_address    = w5100_set_macaddr,
        .ndo_validate_addr      = eth_validate_addr,
};

static int w5100_mmio_probe(struct platform_device *pdev)
{
        struct wiznet_platform_data *data = dev_get_platdata(&pdev->dev);
        const void *mac_addr = NULL;
        struct resource *mem;
        const struct w5100_ops *ops;
        int irq;

        if (data && is_valid_ether_addr(data->mac_addr))
                mac_addr = data->mac_addr;

        mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (resource_size(mem) < W5100_BUS_DIRECT_SIZE)
                ops = &w5100_mmio_indirect_ops;
        else
                ops = &w5100_mmio_direct_ops;

        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
                return irq;

        return w5100_probe(&pdev->dev, ops, sizeof(struct w5100_mmio_priv),
                           mac_addr, irq, data ? data->link_gpio : -EINVAL);
}

static int w5100_mmio_remove(struct platform_device *pdev)
{
        return w5100_remove(&pdev->dev);
}

void *w5100_ops_priv(const struct net_device *ndev)
{
        return netdev_priv(ndev) +
               ALIGN(sizeof(struct w5100_priv), NETDEV_ALIGN);
}
EXPORT_SYMBOL_GPL(w5100_ops_priv);

int w5100_probe(struct device *dev, const struct w5100_ops *ops,
                int sizeof_ops_priv, const void *mac_addr, int irq,
                int link_gpio)
{
        struct w5100_priv *priv;
        struct net_device *ndev;
        int err;
        size_t alloc_size;

        alloc_size = sizeof(*priv);
        if (sizeof_ops_priv) {
                alloc_size = ALIGN(alloc_size, NETDEV_ALIGN);
                alloc_size += sizeof_ops_priv;
        }
        alloc_size += NETDEV_ALIGN - 1;

        ndev = alloc_etherdev(alloc_size);
        if (!ndev)
                return -ENOMEM;
        SET_NETDEV_DEV(ndev, dev);
        dev_set_drvdata(dev, ndev);
        priv = netdev_priv(ndev);

        switch (ops->chip_id) {
        case W5100:
                priv->s0_regs = W5100_S0_REGS;
                priv->s0_tx_buf = W5100_TX_MEM_START;
                priv->s0_tx_buf_size = W5100_TX_MEM_SIZE;
                priv->s0_rx_buf = W5100_RX_MEM_START;
                priv->s0_rx_buf_size = W5100_RX_MEM_SIZE;
                break;
        case W5200:
                priv->s0_regs = W5200_S0_REGS;
                priv->s0_tx_buf = W5200_TX_MEM_START;
                priv->s0_tx_buf_size = W5200_TX_MEM_SIZE;
                priv->s0_rx_buf = W5200_RX_MEM_START;
                priv->s0_rx_buf_size = W5200_RX_MEM_SIZE;
                break;
        case W5500:
                priv->s0_regs = W5500_S0_REGS;
                priv->s0_tx_buf = W5500_TX_MEM_START;
                priv->s0_tx_buf_size = W5500_TX_MEM_SIZE;
                priv->s0_rx_buf = W5500_RX_MEM_START;
                priv->s0_rx_buf_size = W5500_RX_MEM_SIZE;
                break;
        default:
                err = -EINVAL;
                goto err_register;
        }

        priv->ndev = ndev;
        priv->ops = ops;
        priv->irq = irq;
        priv->link_gpio = link_gpio;

        ndev->netdev_ops = &w5100_netdev_ops;
        ndev->ethtool_ops = &w5100_ethtool_ops;
        netif_napi_add(ndev, &priv->napi, w5100_napi_poll, 16);

        /* This chip doesn't support VLAN packets with normal MTU,
         * so disable VLAN for this device.
         */
        ndev->features |= NETIF_F_VLAN_CHALLENGED;

        err = register_netdev(ndev);
        if (err < 0)
                goto err_register;

        priv->xfer_wq = alloc_workqueue("%s", WQ_MEM_RECLAIM, 0,
                                        netdev_name(ndev));
        if (!priv->xfer_wq) {
                err = -ENOMEM;
                goto err_wq;
        }

        INIT_WORK(&priv->rx_work, w5100_rx_work);
        INIT_WORK(&priv->tx_work, w5100_tx_work);
        INIT_WORK(&priv->setrx_work, w5100_setrx_work);
        INIT_WORK(&priv->restart_work, w5100_restart_work);

        if (mac_addr)
                memcpy(ndev->dev_addr, mac_addr, ETH_ALEN);
        else
                eth_hw_addr_random(ndev);

        if (priv->ops->init) {
                err = priv->ops->init(priv->ndev);
                if (err)
                        goto err_hw;
        }

        err = w5100_hw_reset(priv);
        if (err)
                goto err_hw;

        if (ops->may_sleep) {
                err = request_threaded_irq(priv->irq, NULL, w5100_interrupt,
                                           IRQF_TRIGGER_LOW | IRQF_ONESHOT,
                                           netdev_name(ndev), ndev);
        } else {
                err = request_irq(priv->irq, w5100_interrupt,
                                  IRQF_TRIGGER_LOW, netdev_name(ndev), ndev);
        }
        if (err)
                goto err_hw;

        if (gpio_is_valid(priv->link_gpio)) {
                char *link_name = devm_kzalloc(dev, 16, GFP_KERNEL);

                if (!link_name) {
                        err = -ENOMEM;
                        goto err_gpio;
                }
                snprintf(link_name, 16, "%s-link", netdev_name(ndev));
                priv->link_irq = gpio_to_irq(priv->link_gpio);
                if (request_any_context_irq(priv->link_irq, w5100_detect_link,
                                            IRQF_TRIGGER_RISING |
                                            IRQF_TRIGGER_FALLING,
                                            link_name, priv->ndev) < 0)
                        priv->link_gpio = -EINVAL;
        }

        return 0;

err_gpio:
        free_irq(priv->irq, ndev);
err_hw:
        destroy_workqueue(priv->xfer_wq);
err_wq:
        unregister_netdev(ndev);
err_register:
        free_netdev(ndev);
        return err;
}
EXPORT_SYMBOL_GPL(w5100_probe);

int w5100_remove(struct device *dev)
{
        struct net_device *ndev = dev_get_drvdata(dev);
        struct w5100_priv *priv = netdev_priv(ndev);

        w5100_hw_reset(priv);
        free_irq(priv->irq, ndev);
        if (gpio_is_valid(priv->link_gpio))
                free_irq(priv->link_irq, ndev);

        flush_work(&priv->setrx_work);
        flush_work(&priv->restart_work);
        destroy_workqueue(priv->xfer_wq);

        unregister_netdev(ndev);
        free_netdev(ndev);
        return 0;
}
EXPORT_SYMBOL_GPL(w5100_remove);

#ifdef CONFIG_PM_SLEEP
static int w5100_suspend(struct device *dev)
{
        struct net_device *ndev = dev_get_drvdata(dev);
        struct w5100_priv *priv = netdev_priv(ndev);

        if (netif_running(ndev)) {
                netif_carrier_off(ndev);
                netif_device_detach(ndev);

                w5100_hw_close(priv);
        }
        return 0;
}

static int w5100_resume(struct device *dev)
{
        struct net_device *ndev = dev_get_drvdata(dev);
        struct w5100_priv *priv = netdev_priv(ndev);

        if (netif_running(ndev)) {
                w5100_hw_reset(priv);
                w5100_hw_start(priv);

                netif_device_attach(ndev);
                if (!gpio_is_valid(priv->link_gpio) ||
                    gpio_get_value(priv->link_gpio) != 0)
                        netif_carrier_on(ndev);
        }
        return 0;
}
#endif /* CONFIG_PM_SLEEP */

SIMPLE_DEV_PM_OPS(w5100_pm_ops, w5100_suspend, w5100_resume);
EXPORT_SYMBOL_GPL(w5100_pm_ops);

static struct platform_driver w5100_mmio_driver = {
        .driver         = {
                .name   = DRV_NAME,
                .pm     = &w5100_pm_ops,
        },
        .probe          = w5100_mmio_probe,
        .remove         = w5100_mmio_remove,
};
module_platform_driver(w5100_mmio_driver);