/*
 * Ethernet driver for the WIZnet W5300 chip.
 *
 * Copyright (C) 2008-2009 WIZnet Co.,Ltd.
 * Copyright (C) 2011 Taehun Kim <kth3321 <at> gmail.com>
 * 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>

#define DRV_NAME        "w5300"
#define DRV_VERSION     "2012-04-04"

MODULE_DESCRIPTION("WIZnet W5300 Ethernet driver v"DRV_VERSION);
MODULE_AUTHOR("Mike Sinkovsky <msink@permonline.ru>");
MODULE_ALIAS("platform:"DRV_NAME);
MODULE_LICENSE("GPL");

/*
 * Registers
 */
#define W5300_MR                0x0000  /* Mode Register */
#define   MR_DBW                  (1 << 15) /* Data bus width */
#define   MR_MPF                  (1 << 14) /* Mac layer pause frame */
#define   MR_WDF(n)               (((n)&7)<<11) /* Write data fetch time */
#define   MR_RDH                  (1 << 10) /* Read data hold time */
#define   MR_FS                   (1 << 8)  /* FIFO swap */
#define   MR_RST                  (1 << 7)  /* S/W reset */
#define   MR_PB                   (1 << 4)  /* Ping block */
#define   MR_DBS                  (1 << 2)  /* Data bus swap */
#define   MR_IND                  (1 << 0)  /* Indirect mode */
#define W5300_IR                0x0002  /* Interrupt Register */
#define W5300_IMR               0x0004  /* Interrupt Mask Register */
#define   IR_S0                   0x0001  /* S0 interrupt */
#define W5300_SHARL             0x0008  /* Source MAC address (0123) */
#define W5300_SHARH             0x000c  /* Source MAC address (45) */
#define W5300_TMSRL             0x0020  /* Transmit Memory Size (0123) */
#define W5300_TMSRH             0x0024  /* Transmit Memory Size (4567) */
#define W5300_RMSRL             0x0028  /* Receive Memory Size (0123) */
#define W5300_RMSRH             0x002c  /* Receive Memory Size (4567) */
#define W5300_MTYPE             0x0030  /* Memory Type */
#define W5300_IDR               0x00fe  /* Chip ID register */
#define   IDR_W5300               0x5300  /* =0x5300 for WIZnet W5300 */
#define W5300_S0_MR             0x0200  /* S0 Mode Register */
#define   S0_MR_CLOSED            0x0000  /* Close mode */
#define   S0_MR_MACRAW            0x0004  /* MAC RAW mode (promiscuous) */
#define   S0_MR_MACRAW_MF         0x0044  /* MAC RAW mode (filtered) */
#define W5300_S0_CR             0x0202  /* S0 Command Register */
#define   S0_CR_OPEN              0x0001  /* OPEN command */
#define   S0_CR_CLOSE             0x0010  /* CLOSE command */
#define   S0_CR_SEND              0x0020  /* SEND command */
#define   S0_CR_RECV              0x0040  /* RECV command */
#define W5300_S0_IMR            0x0204  /* S0 Interrupt Mask Register */
#define W5300_S0_IR             0x0206  /* S0 Interrupt Register */
#define   S0_IR_RECV              0x0004  /* Receive interrupt */
#define   S0_IR_SENDOK            0x0010  /* Send OK interrupt */
#define W5300_S0_SSR            0x0208  /* S0 Socket Status Register */
#define W5300_S0_TX_WRSR        0x0220  /* S0 TX Write Size Register */
#define W5300_S0_TX_FSR         0x0224  /* S0 TX Free Size Register */
#define W5300_S0_RX_RSR         0x0228  /* S0 Received data Size */
#define W5300_S0_TX_FIFO        0x022e  /* S0 Transmit FIFO */
#define W5300_S0_RX_FIFO        0x0230  /* S0 Receive FIFO */
#define W5300_REGS_LEN          0x0400

/*
 * Device driver private data structure
 */
struct w5300_priv {
        void __iomem *base;
        spinlock_t reg_lock;
        bool indirect;
        u16  (*read) (struct w5300_priv *priv, u16 addr);
        void (*write)(struct w5300_priv *priv, u16 addr, u16 data);
        int irq;
        int link_irq;
        int link_gpio;

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

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

/*
 * In direct address mode host system can directly access W5300 registers
 * after mapping to Memory-Mapped I/O space.
 *
 * 0x400 bytes are required for memory space.
 */
static inline u16 w5300_read_direct(struct w5300_priv *priv, u16 addr)
{
        return ioread16(priv->base + (addr << CONFIG_WIZNET_BUS_SHIFT));
}

static inline void w5300_write_direct(struct w5300_priv *priv,
                                      u16 addr, u16 data)
{
        iowrite16(data, priv->base + (addr << CONFIG_WIZNET_BUS_SHIFT));
}

/*
 * 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 0x06 bytes are required for memory space.
 */
#define W5300_IDM_AR            0x0002   /* Indirect Mode Address */
#define W5300_IDM_DR            0x0004   /* Indirect Mode Data */

static u16 w5300_read_indirect(struct w5300_priv *priv, u16 addr)
{
        unsigned long flags;
        u16 data;

        spin_lock_irqsave(&priv->reg_lock, flags);
        w5300_write_direct(priv, W5300_IDM_AR, addr);
        mmiowb();
        data = w5300_read_direct(priv, W5300_IDM_DR);
        spin_unlock_irqrestore(&priv->reg_lock, flags);

        return data;
}

static void w5300_write_indirect(struct w5300_priv *priv, u16 addr, u16 data)
{
        unsigned long flags;

        spin_lock_irqsave(&priv->reg_lock, flags);
        w5300_write_direct(priv, W5300_IDM_AR, addr);
        mmiowb();
        w5300_write_direct(priv, W5300_IDM_DR, data);
        mmiowb();
        spin_unlock_irqrestore(&priv->reg_lock, flags);
}

#if defined(CONFIG_WIZNET_BUS_DIRECT)
#define w5300_read      w5300_read_direct
#define w5300_write     w5300_write_direct

#elif defined(CONFIG_WIZNET_BUS_INDIRECT)
#define w5300_read      w5300_read_indirect
#define w5300_write     w5300_write_indirect

#else /* CONFIG_WIZNET_BUS_ANY */
#define w5300_read      priv->read
#define w5300_write     priv->write
#endif

static u32 w5300_read32(struct w5300_priv *priv, u16 addr)
{
        u32 data;
        data  = w5300_read(priv, addr) << 16;
        data |= w5300_read(priv, addr + 2);
        return data;
}

static void w5300_write32(struct w5300_priv *priv, u16 addr, u32 data)
{
        w5300_write(priv, addr, data >> 16);
        w5300_write(priv, addr + 2, data);
}

static int w5300_command(struct w5300_priv *priv, u16 cmd)
{
        unsigned long timeout = jiffies + msecs_to_jiffies(100);

        w5300_write(priv, W5300_S0_CR, cmd);
        mmiowb();

        while (w5300_read(priv, W5300_S0_CR) != 0) {
                if (time_after(jiffies, timeout))
                        return -EIO;
                cpu_relax();
        }

        return 0;
}

static void w5300_read_frame(struct w5300_priv *priv, u8 *buf, int len)
{
        u16 fifo;
        int i;

        for (i = 0; i < len; i += 2) {
                fifo = w5300_read(priv, W5300_S0_RX_FIFO);
                *buf++ = fifo >> 8;
                *buf++ = fifo;
        }
        fifo = w5300_read(priv, W5300_S0_RX_FIFO);
        fifo = w5300_read(priv, W5300_S0_RX_FIFO);
}

static void w5300_write_frame(struct w5300_priv *priv, u8 *buf, int len)
{
        u16 fifo;
        int i;

        for (i = 0; i < len; i += 2) {
                fifo  = *buf++ << 8;
                fifo |= *buf++;
                w5300_write(priv, W5300_S0_TX_FIFO, fifo);
        }
        w5300_write32(priv, W5300_S0_TX_WRSR, len);
}

static void w5300_write_macaddr(struct w5300_priv *priv)
{
        struct net_device *ndev = priv->ndev;
        w5300_write32(priv, W5300_SHARL,
                      ndev->dev_addr[0] << 24 |
                      ndev->dev_addr[1] << 16 |
                      ndev->dev_addr[2] << 8 |
                      ndev->dev_addr[3]);
        w5300_write(priv, W5300_SHARH,
                      ndev->dev_addr[4] << 8 |
                      ndev->dev_addr[5]);
        mmiowb();
}

static void w5300_hw_reset(struct w5300_priv *priv)
{
        w5300_write_direct(priv, W5300_MR, MR_RST);
        mmiowb();
        mdelay(5);
        w5300_write_direct(priv, W5300_MR, priv->indirect ?
                                 MR_WDF(7) | MR_PB | MR_IND :
                                 MR_WDF(7) | MR_PB);
        mmiowb();
        w5300_write(priv, W5300_IMR, 0);
        w5300_write_macaddr(priv);

        /* Configure 128K of internal memory
         * as 64K RX fifo and 64K TX fifo
         */
        w5300_write32(priv, W5300_RMSRL, 64 << 24);
        w5300_write32(priv, W5300_RMSRH, 0);
        w5300_write32(priv, W5300_TMSRL, 64 << 24);
        w5300_write32(priv, W5300_TMSRH, 0);
        w5300_write(priv, W5300_MTYPE, 0x00ff);
        mmiowb();
}

static void w5300_hw_start(struct w5300_priv *priv)
{
        w5300_write(priv, W5300_S0_MR, priv->promisc ?
                          S0_MR_MACRAW : S0_MR_MACRAW_MF);
        mmiowb();
        w5300_command(priv, S0_CR_OPEN);
        w5300_write(priv, W5300_S0_IMR, S0_IR_RECV | S0_IR_SENDOK);
        w5300_write(priv, W5300_IMR, IR_S0);
        mmiowb();
}

static void w5300_hw_close(struct w5300_priv *priv)
{
        w5300_write(priv, W5300_IMR, 0);
        mmiowb();
        w5300_command(priv, S0_CR_CLOSE);
}

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

static void w5300_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 w5300_get_link(struct net_device *ndev)
{
        struct w5300_priv *priv = netdev_priv(ndev);

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

        return 1;
}

static u32 w5300_get_msglevel(struct net_device *ndev)
{
        struct w5300_priv *priv = netdev_priv(ndev);

        return priv->msg_enable;
}

static void w5300_set_msglevel(struct net_device *ndev, u32 value)
{
        struct w5300_priv *priv = netdev_priv(ndev);

        priv->msg_enable = value;
}

static int w5300_get_regs_len(struct net_device *ndev)
{
        return W5300_REGS_LEN;
}

static void w5300_get_regs(struct net_device *ndev,
                           struct ethtool_regs *regs, void *_buf)
{
        struct w5300_priv *priv = netdev_priv(ndev);
        u8 *buf = _buf;
        u16 addr;
        u16 data;

        regs->version = 1;
        for (addr = 0; addr < W5300_REGS_LEN; addr += 2) {
                switch (addr & 0x23f) {
                case W5300_S0_TX_FIFO: /* cannot read TX_FIFO */
                case W5300_S0_RX_FIFO: /* cannot read RX_FIFO */
                        data = 0xffff;
                        break;
                default:
                        data = w5300_read(priv, addr);
                        break;
                }
                *buf++ = data >> 8;
                *buf++ = data;
        }
}

static void w5300_tx_timeout(struct net_device *ndev)
{
        struct w5300_priv *priv = netdev_priv(ndev);

        netif_stop_queue(ndev);
        w5300_hw_reset(priv);
        w5300_hw_start(priv);
        ndev->stats.tx_errors++;
        netif_trans_update(ndev);
        netif_wake_queue(ndev);
}

static int w5300_start_tx(struct sk_buff *skb, struct net_device *ndev)
{
        struct w5300_priv *priv = netdev_priv(ndev);

        netif_stop_queue(ndev);

        w5300_write_frame(priv, skb->data, skb->len);
        mmiowb();
        ndev->stats.tx_packets++;
        ndev->stats.tx_bytes += skb->len;
        dev_kfree_skb(skb);
        netif_dbg(priv, tx_queued, ndev, "tx queued\n");

        w5300_command(priv, S0_CR_SEND);

        return NETDEV_TX_OK;
}

static int w5300_napi_poll(struct napi_struct *napi, int budget)
{
        struct w5300_priv *priv = container_of(napi, struct w5300_priv, napi);
        struct net_device *ndev = priv->ndev;
        struct sk_buff *skb;
        int rx_count;
        u16 rx_len;

        for (rx_count = 0; rx_count < budget; rx_count++) {
                u32 rx_fifo_len = w5300_read32(priv, W5300_S0_RX_RSR);
                if (rx_fifo_len == 0)
                        break;

                rx_len = w5300_read(priv, W5300_S0_RX_FIFO);

                skb = netdev_alloc_skb_ip_align(ndev, roundup(rx_len, 2));
                if (unlikely(!skb)) {
                        u32 i;
                        for (i = 0; i < rx_fifo_len; i += 2)
                                w5300_read(priv, W5300_S0_RX_FIFO);
                        ndev->stats.rx_dropped++;
                        return -ENOMEM;
                }

                skb_put(skb, rx_len);
                w5300_read_frame(priv, skb->data, rx_len);
                skb->protocol = eth_type_trans(skb, ndev);

                netif_receive_skb(skb);
                ndev->stats.rx_packets++;
                ndev->stats.rx_bytes += rx_len;
        }

        if (rx_count < budget) {
                napi_complete(napi);
                w5300_write(priv, W5300_IMR, IR_S0);
                mmiowb();
        }

        return rx_count;
}

static irqreturn_t w5300_interrupt(int irq, void *ndev_instance)
{
        struct net_device *ndev = ndev_instance;
        struct w5300_priv *priv = netdev_priv(ndev);

        int ir = w5300_read(priv, W5300_S0_IR);
        if (!ir)
                return IRQ_NONE;
        w5300_write(priv, W5300_S0_IR, ir);
        mmiowb();

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

        if (ir & S0_IR_RECV) {
                if (napi_schedule_prep(&priv->napi)) {
                        w5300_write(priv, W5300_IMR, 0);
                        mmiowb();
                        __napi_schedule(&priv->napi);
                }
        }

        return IRQ_HANDLED;
}

static irqreturn_t w5300_detect_link(int irq, void *ndev_instance)
{
        struct net_device *ndev = ndev_instance;
        struct w5300_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 w5300_set_rx_mode(struct net_device *ndev)
{
        struct w5300_priv *priv = netdev_priv(ndev);
        bool set_promisc = (ndev->flags & IFF_PROMISC) != 0;

        if (priv->promisc != set_promisc) {
                priv->promisc = set_promisc;
                w5300_hw_start(priv);
        }
}

static int w5300_set_macaddr(struct net_device *ndev, void *addr)
{
        struct w5300_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);
        w5300_write_macaddr(priv);
        return 0;
}

static int w5300_open(struct net_device *ndev)
{
        struct w5300_priv *priv = netdev_priv(ndev);

        netif_info(priv, ifup, ndev, "enabling\n");
        w5300_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 w5300_stop(struct net_device *ndev)
{
        struct w5300_priv *priv = netdev_priv(ndev);

        netif_info(priv, ifdown, ndev, "shutting down\n");
        w5300_hw_close(priv);
        netif_carrier_off(ndev);
        netif_stop_queue(ndev);
        napi_disable(&priv->napi);
        return 0;
}

static const struct ethtool_ops w5300_ethtool_ops = {
        .get_drvinfo            = w5300_get_drvinfo,
        .get_msglevel           = w5300_get_msglevel,
        .set_msglevel           = w5300_set_msglevel,
        .get_link               = w5300_get_link,
        .get_regs_len           = w5300_get_regs_len,
        .get_regs               = w5300_get_regs,
};

static const struct net_device_ops w5300_netdev_ops = {
        .ndo_open               = w5300_open,
        .ndo_stop               = w5300_stop,
        .ndo_start_xmit         = w5300_start_tx,
        .ndo_tx_timeout         = w5300_tx_timeout,
        .ndo_set_rx_mode        = w5300_set_rx_mode,
        .ndo_set_mac_address    = w5300_set_macaddr,
        .ndo_validate_addr      = eth_validate_addr,
        .ndo_change_mtu         = eth_change_mtu,
};

static int w5300_hw_probe(struct platform_device *pdev)
{
        struct wiznet_platform_data *data = dev_get_platdata(&pdev->dev);
        struct net_device *ndev = platform_get_drvdata(pdev);
        struct w5300_priv *priv = netdev_priv(ndev);
        const char *name = netdev_name(ndev);
        struct resource *mem;
        int mem_size;
        int irq;
        int ret;

        if (data && is_valid_ether_addr(data->mac_addr)) {
                memcpy(ndev->dev_addr, data->mac_addr, ETH_ALEN);
        } else {
                eth_hw_addr_random(ndev);
        }

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

        mem_size = resource_size(mem);

        spin_lock_init(&priv->reg_lock);
        priv->indirect = mem_size < W5300_BUS_DIRECT_SIZE;
        if (priv->indirect) {
                priv->read  = w5300_read_indirect;
                priv->write = w5300_write_indirect;
        } else {
                priv->read  = w5300_read_direct;
                priv->write = w5300_write_direct;
        }

        w5300_hw_reset(priv);
        if (w5300_read(priv, W5300_IDR) != IDR_W5300)
                return -ENODEV;

        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
                return irq;
        ret = request_irq(irq, w5300_interrupt,
                          IRQ_TYPE_LEVEL_LOW, name, ndev);
        if (ret < 0)
                return ret;
        priv->irq = irq;

        priv->link_gpio = data ? data->link_gpio : -EINVAL;
        if (gpio_is_valid(priv->link_gpio)) {
                char *link_name = devm_kzalloc(&pdev->dev, 16, GFP_KERNEL);
                if (!link_name)
                        return -ENOMEM;
                snprintf(link_name, 16, "%s-link", name);
                priv->link_irq = gpio_to_irq(priv->link_gpio);
                if (request_any_context_irq(priv->link_irq, w5300_detect_link,
                                IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
                                link_name, priv->ndev) < 0)
                        priv->link_gpio = -EINVAL;
        }

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

static int w5300_probe(struct platform_device *pdev)
{
        struct w5300_priv *priv;
        struct net_device *ndev;
        int err;

        ndev = alloc_etherdev(sizeof(*priv));
        if (!ndev)
                return -ENOMEM;
        SET_NETDEV_DEV(ndev, &pdev->dev);
        platform_set_drvdata(pdev, ndev);
        priv = netdev_priv(ndev);
        priv->ndev = ndev;

        ndev->netdev_ops = &w5300_netdev_ops;
        ndev->ethtool_ops = &w5300_ethtool_ops;
        ndev->watchdog_timeo = HZ;
        netif_napi_add(ndev, &priv->napi, w5300_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;

        err = w5300_hw_probe(pdev);
        if (err < 0)
                goto err_hw_probe;

        return 0;

err_hw_probe:
        unregister_netdev(ndev);
err_register:
        free_netdev(ndev);
        return err;
}

static int w5300_remove(struct platform_device *pdev)
{
        struct net_device *ndev = platform_get_drvdata(pdev);
        struct w5300_priv *priv = netdev_priv(ndev);

        w5300_hw_reset(priv);
        free_irq(priv->irq, ndev);
        if (gpio_is_valid(priv->link_gpio))
                free_irq(priv->link_irq, ndev);

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

#ifdef CONFIG_PM_SLEEP
static int w5300_suspend(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct net_device *ndev = platform_get_drvdata(pdev);
        struct w5300_priv *priv = netdev_priv(ndev);

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

                w5300_hw_close(priv);
        }
        return 0;
}

static int w5300_resume(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct net_device *ndev = platform_get_drvdata(pdev);
        struct w5300_priv *priv = netdev_priv(ndev);

        if (!netif_running(ndev)) {
                w5300_hw_reset(priv);
                w5300_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 */

static SIMPLE_DEV_PM_OPS(w5300_pm_ops, w5300_suspend, w5300_resume);

static struct platform_driver w5300_driver = {
        .driver         = {
                .name   = DRV_NAME,
                .pm     = &w5300_pm_ops,
        },
        .probe          = w5300_probe,
        .remove         = w5300_remove,
};

module_platform_driver(w5300_driver);