env: Rename getenv/_f() to env_get()

[people/ms/u-boot.git] / drivers / net / fec_mxc.c

/*
 * (C) Copyright 2009 Ilya Yanok, Emcraft Systems Ltd <yanok@emcraft.com>
 * (C) Copyright 2008,2009 Eric Jarrige <eric.jarrige@armadeus.org>
 * (C) Copyright 2008 Armadeus Systems nc
 * (C) Copyright 2007 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de>
 * (C) Copyright 2007 Pengutronix, Juergen Beisert <j.beisert@pengutronix.de>
 *
 * SPDX-License-Identifier:     GPL-2.0+
 */

#include <common.h>
#include <dm.h>
#include <malloc.h>
#include <memalign.h>
#include <miiphy.h>
#include <net.h>
#include <netdev.h>
#include "fec_mxc.h"

#include <asm/io.h>
#include <linux/errno.h>
#include <linux/compiler.h>

#include <asm/arch/clock.h>
#include <asm/arch/imx-regs.h>
#include <asm/mach-imx/sys_proto.h>

DECLARE_GLOBAL_DATA_PTR;

/*
 * Timeout the transfer after 5 mS. This is usually a bit more, since
 * the code in the tightloops this timeout is used in adds some overhead.
 */
#define FEC_XFER_TIMEOUT        5000

/*
 * The standard 32-byte DMA alignment does not work on mx6solox, which requires
 * 64-byte alignment in the DMA RX FEC buffer.
 * Introduce the FEC_DMA_RX_MINALIGN which can cover mx6solox needs and also
 * satisfies the alignment on other SoCs (32-bytes)
 */
#define FEC_DMA_RX_MINALIGN     64

#ifndef CONFIG_MII
#error "CONFIG_MII has to be defined!"
#endif

#ifndef CONFIG_FEC_XCV_TYPE
#define CONFIG_FEC_XCV_TYPE MII100
#endif

/*
 * The i.MX28 operates with packets in big endian. We need to swap them before
 * sending and after receiving.
 */
#ifdef CONFIG_MX28
#define CONFIG_FEC_MXC_SWAP_PACKET
#endif

#define RXDESC_PER_CACHELINE (ARCH_DMA_MINALIGN/sizeof(struct fec_bd))

/* Check various alignment issues at compile time */
#if ((ARCH_DMA_MINALIGN < 16) || (ARCH_DMA_MINALIGN % 16 != 0))
#error "ARCH_DMA_MINALIGN must be multiple of 16!"
#endif

#if ((PKTALIGN < ARCH_DMA_MINALIGN) || \
        (PKTALIGN % ARCH_DMA_MINALIGN != 0))
#error "PKTALIGN must be multiple of ARCH_DMA_MINALIGN!"
#endif

#undef DEBUG

#ifdef CONFIG_FEC_MXC_SWAP_PACKET
static void swap_packet(uint32_t *packet, int length)
{
        int i;

        for (i = 0; i < DIV_ROUND_UP(length, 4); i++)
                packet[i] = __swab32(packet[i]);
}
#endif

/* MII-interface related functions */
static int fec_mdio_read(struct ethernet_regs *eth, uint8_t phyaddr,
                uint8_t regaddr)
{
        uint32_t reg;           /* convenient holder for the PHY register */
        uint32_t phy;           /* convenient holder for the PHY */
        uint32_t start;
        int val;

        /*
         * reading from any PHY's register is done by properly
         * programming the FEC's MII data register.
         */
        writel(FEC_IEVENT_MII, &eth->ievent);
        reg = regaddr << FEC_MII_DATA_RA_SHIFT;
        phy = phyaddr << FEC_MII_DATA_PA_SHIFT;

        writel(FEC_MII_DATA_ST | FEC_MII_DATA_OP_RD | FEC_MII_DATA_TA |
                        phy | reg, &eth->mii_data);

        /* wait for the related interrupt */
        start = get_timer(0);
        while (!(readl(&eth->ievent) & FEC_IEVENT_MII)) {
                if (get_timer(start) > (CONFIG_SYS_HZ / 1000)) {
                        printf("Read MDIO failed...\n");
                        return -1;
                }
        }

        /* clear mii interrupt bit */
        writel(FEC_IEVENT_MII, &eth->ievent);

        /* it's now safe to read the PHY's register */
        val = (unsigned short)readl(&eth->mii_data);
        debug("%s: phy: %02x reg:%02x val:%#x\n", __func__, phyaddr,
              regaddr, val);
        return val;
}

static void fec_mii_setspeed(struct ethernet_regs *eth)
{
        /*
         * Set MII_SPEED = (1/(mii_speed * 2)) * System Clock
         * and do not drop the Preamble.
         *
         * The i.MX28 and i.MX6 types have another field in the MSCR (aka
         * MII_SPEED) register that defines the MDIO output hold time. Earlier
         * versions are RAZ there, so just ignore the difference and write the
         * register always.
         * The minimal hold time according to IEE802.3 (clause 22) is 10 ns.
         * HOLDTIME + 1 is the number of clk cycles the fec is holding the
         * output.
         * The HOLDTIME bitfield takes values between 0 and 7 (inclusive).
         * Given that ceil(clkrate / 5000000) <= 64, the calculation for
         * holdtime cannot result in a value greater than 3.
         */
        u32 pclk = imx_get_fecclk();
        u32 speed = DIV_ROUND_UP(pclk, 5000000);
        u32 hold = DIV_ROUND_UP(pclk, 100000000) - 1;
#ifdef FEC_QUIRK_ENET_MAC
        speed--;
#endif
        writel(speed << 1 | hold << 8, &eth->mii_speed);
        debug("%s: mii_speed %08x\n", __func__, readl(&eth->mii_speed));
}

static int fec_mdio_write(struct ethernet_regs *eth, uint8_t phyaddr,
                uint8_t regaddr, uint16_t data)
{
        uint32_t reg;           /* convenient holder for the PHY register */
        uint32_t phy;           /* convenient holder for the PHY */
        uint32_t start;

        reg = regaddr << FEC_MII_DATA_RA_SHIFT;
        phy = phyaddr << FEC_MII_DATA_PA_SHIFT;

        writel(FEC_MII_DATA_ST | FEC_MII_DATA_OP_WR |
                FEC_MII_DATA_TA | phy | reg | data, &eth->mii_data);

        /* wait for the MII interrupt */
        start = get_timer(0);
        while (!(readl(&eth->ievent) & FEC_IEVENT_MII)) {
                if (get_timer(start) > (CONFIG_SYS_HZ / 1000)) {
                        printf("Write MDIO failed...\n");
                        return -1;
                }
        }

        /* clear MII interrupt bit */
        writel(FEC_IEVENT_MII, &eth->ievent);
        debug("%s: phy: %02x reg:%02x val:%#x\n", __func__, phyaddr,
              regaddr, data);

        return 0;
}

static int fec_phy_read(struct mii_dev *bus, int phyaddr, int dev_addr,
                        int regaddr)
{
        return fec_mdio_read(bus->priv, phyaddr, regaddr);
}

static int fec_phy_write(struct mii_dev *bus, int phyaddr, int dev_addr,
                         int regaddr, u16 data)
{
        return fec_mdio_write(bus->priv, phyaddr, regaddr, data);
}

#ifndef CONFIG_PHYLIB
static int miiphy_restart_aneg(struct eth_device *dev)
{
        int ret = 0;
#if !defined(CONFIG_FEC_MXC_NO_ANEG)
        struct fec_priv *fec = (struct fec_priv *)dev->priv;
        struct ethernet_regs *eth = fec->bus->priv;

        /*
         * Wake up from sleep if necessary
         * Reset PHY, then delay 300ns
         */
#ifdef CONFIG_MX27
        fec_mdio_write(eth, fec->phy_id, MII_DCOUNTER, 0x00FF);
#endif
        fec_mdio_write(eth, fec->phy_id, MII_BMCR, BMCR_RESET);
        udelay(1000);

        /* Set the auto-negotiation advertisement register bits */
        fec_mdio_write(eth, fec->phy_id, MII_ADVERTISE,
                       LPA_100FULL | LPA_100HALF | LPA_10FULL |
                       LPA_10HALF | PHY_ANLPAR_PSB_802_3);
        fec_mdio_write(eth, fec->phy_id, MII_BMCR,
                       BMCR_ANENABLE | BMCR_ANRESTART);

        if (fec->mii_postcall)
                ret = fec->mii_postcall(fec->phy_id);

#endif
        return ret;
}

#ifndef CONFIG_FEC_FIXED_SPEED
static int miiphy_wait_aneg(struct eth_device *dev)
{
        uint32_t start;
        int status;
        struct fec_priv *fec = (struct fec_priv *)dev->priv;
        struct ethernet_regs *eth = fec->bus->priv;

        /* Wait for AN completion */
        start = get_timer(0);
        do {
                if (get_timer(start) > (CONFIG_SYS_HZ * 5)) {
                        printf("%s: Autonegotiation timeout\n", dev->name);
                        return -1;
                }

                status = fec_mdio_read(eth, fec->phy_id, MII_BMSR);
                if (status < 0) {
                        printf("%s: Autonegotiation failed. status: %d\n",
                               dev->name, status);
                        return -1;
                }
        } while (!(status & BMSR_LSTATUS));

        return 0;
}
#endif /* CONFIG_FEC_FIXED_SPEED */
#endif

static int fec_rx_task_enable(struct fec_priv *fec)
{
        writel(FEC_R_DES_ACTIVE_RDAR, &fec->eth->r_des_active);
        return 0;
}

static int fec_rx_task_disable(struct fec_priv *fec)
{
        return 0;
}

static int fec_tx_task_enable(struct fec_priv *fec)
{
        writel(FEC_X_DES_ACTIVE_TDAR, &fec->eth->x_des_active);
        return 0;
}

static int fec_tx_task_disable(struct fec_priv *fec)
{
        return 0;
}

/**
 * Initialize receive task's buffer descriptors
 * @param[in] fec all we know about the device yet
 * @param[in] count receive buffer count to be allocated
 * @param[in] dsize desired size of each receive buffer
 * @return 0 on success
 *
 * Init all RX descriptors to default values.
 */
static void fec_rbd_init(struct fec_priv *fec, int count, int dsize)
{
        uint32_t size;
        uint8_t *data;
        int i;

        /*
         * Reload the RX descriptors with default values and wipe
         * the RX buffers.
         */
        size = roundup(dsize, ARCH_DMA_MINALIGN);
        for (i = 0; i < count; i++) {
                data = (uint8_t *)fec->rbd_base[i].data_pointer;
                memset(data, 0, dsize);
                flush_dcache_range((uint32_t)data, (uint32_t)data + size);

                fec->rbd_base[i].status = FEC_RBD_EMPTY;
                fec->rbd_base[i].data_length = 0;
        }

        /* Mark the last RBD to close the ring. */
        fec->rbd_base[i - 1].status = FEC_RBD_WRAP | FEC_RBD_EMPTY;
        fec->rbd_index = 0;

        flush_dcache_range((unsigned)fec->rbd_base,
                           (unsigned)fec->rbd_base + size);
}

/**
 * Initialize transmit task's buffer descriptors
 * @param[in] fec all we know about the device yet
 *
 * Transmit buffers are created externally. We only have to init the BDs here.\n
 * Note: There is a race condition in the hardware. When only one BD is in
 * use it must be marked with the WRAP bit to use it for every transmitt.
 * This bit in combination with the READY bit results into double transmit
 * of each data buffer. It seems the state machine checks READY earlier then
 * resetting it after the first transfer.
 * Using two BDs solves this issue.
 */
static void fec_tbd_init(struct fec_priv *fec)
{
        unsigned addr = (unsigned)fec->tbd_base;
        unsigned size = roundup(2 * sizeof(struct fec_bd),
                                ARCH_DMA_MINALIGN);

        memset(fec->tbd_base, 0, size);
        fec->tbd_base[0].status = 0;
        fec->tbd_base[1].status = FEC_TBD_WRAP;
        fec->tbd_index = 0;
        flush_dcache_range(addr, addr + size);
}

/**
 * Mark the given read buffer descriptor as free
 * @param[in] last 1 if this is the last buffer descriptor in the chain, else 0
 * @param[in] prbd buffer descriptor to mark free again
 */
static void fec_rbd_clean(int last, struct fec_bd *prbd)
{
        unsigned short flags = FEC_RBD_EMPTY;
        if (last)
                flags |= FEC_RBD_WRAP;
        writew(flags, &prbd->status);
        writew(0, &prbd->data_length);
}

static int fec_get_hwaddr(int dev_id, unsigned char *mac)
{
        imx_get_mac_from_fuse(dev_id, mac);
        return !is_valid_ethaddr(mac);
}

#ifdef CONFIG_DM_ETH
static int fecmxc_set_hwaddr(struct udevice *dev)
#else
static int fec_set_hwaddr(struct eth_device *dev)
#endif
{
#ifdef CONFIG_DM_ETH
        struct fec_priv *fec = dev_get_priv(dev);
        struct eth_pdata *pdata = dev_get_platdata(dev);
        uchar *mac = pdata->enetaddr;
#else
        uchar *mac = dev->enetaddr;
        struct fec_priv *fec = (struct fec_priv *)dev->priv;
#endif

        writel(0, &fec->eth->iaddr1);
        writel(0, &fec->eth->iaddr2);
        writel(0, &fec->eth->gaddr1);
        writel(0, &fec->eth->gaddr2);

        /* Set physical address */
        writel((mac[0] << 24) + (mac[1] << 16) + (mac[2] << 8) + mac[3],
               &fec->eth->paddr1);
        writel((mac[4] << 24) + (mac[5] << 16) + 0x8808, &fec->eth->paddr2);

        return 0;
}

/* Do initial configuration of the FEC registers */
static void fec_reg_setup(struct fec_priv *fec)
{
        uint32_t rcntrl;

        /* Set interrupt mask register */
        writel(0x00000000, &fec->eth->imask);

        /* Clear FEC-Lite interrupt event register(IEVENT) */
        writel(0xffffffff, &fec->eth->ievent);

        /* Set FEC-Lite receive control register(R_CNTRL): */

        /* Start with frame length = 1518, common for all modes. */
        rcntrl = PKTSIZE << FEC_RCNTRL_MAX_FL_SHIFT;
        if (fec->xcv_type != SEVENWIRE)         /* xMII modes */
                rcntrl |= FEC_RCNTRL_FCE | FEC_RCNTRL_MII_MODE;
        if (fec->xcv_type == RGMII)
                rcntrl |= FEC_RCNTRL_RGMII;
        else if (fec->xcv_type == RMII)
                rcntrl |= FEC_RCNTRL_RMII;

        writel(rcntrl, &fec->eth->r_cntrl);
}

/**
 * Start the FEC engine
 * @param[in] dev Our device to handle
 */
#ifdef CONFIG_DM_ETH
static int fec_open(struct udevice *dev)
#else
static int fec_open(struct eth_device *edev)
#endif
{
#ifdef CONFIG_DM_ETH
        struct fec_priv *fec = dev_get_priv(dev);
#else
        struct fec_priv *fec = (struct fec_priv *)edev->priv;
#endif
        int speed;
        uint32_t addr, size;
        int i;

        debug("fec_open: fec_open(dev)\n");
        /* full-duplex, heartbeat disabled */
        writel(1 << 2, &fec->eth->x_cntrl);
        fec->rbd_index = 0;

        /* Invalidate all descriptors */
        for (i = 0; i < FEC_RBD_NUM - 1; i++)
                fec_rbd_clean(0, &fec->rbd_base[i]);
        fec_rbd_clean(1, &fec->rbd_base[i]);

        /* Flush the descriptors into RAM */
        size = roundup(FEC_RBD_NUM * sizeof(struct fec_bd),
                        ARCH_DMA_MINALIGN);
        addr = (uint32_t)fec->rbd_base;
        flush_dcache_range(addr, addr + size);

#ifdef FEC_QUIRK_ENET_MAC
        /* Enable ENET HW endian SWAP */
        writel(readl(&fec->eth->ecntrl) | FEC_ECNTRL_DBSWAP,
               &fec->eth->ecntrl);
        /* Enable ENET store and forward mode */
        writel(readl(&fec->eth->x_wmrk) | FEC_X_WMRK_STRFWD,
               &fec->eth->x_wmrk);
#endif
        /* Enable FEC-Lite controller */
        writel(readl(&fec->eth->ecntrl) | FEC_ECNTRL_ETHER_EN,
               &fec->eth->ecntrl);

#if defined(CONFIG_MX25) || defined(CONFIG_MX53) || defined(CONFIG_MX6SL)
        udelay(100);

        /* setup the MII gasket for RMII mode */
        /* disable the gasket */
        writew(0, &fec->eth->miigsk_enr);

        /* wait for the gasket to be disabled */
        while (readw(&fec->eth->miigsk_enr) & MIIGSK_ENR_READY)
                udelay(2);

        /* configure gasket for RMII, 50 MHz, no loopback, and no echo */
        writew(MIIGSK_CFGR_IF_MODE_RMII, &fec->eth->miigsk_cfgr);

        /* re-enable the gasket */
        writew(MIIGSK_ENR_EN, &fec->eth->miigsk_enr);

        /* wait until MII gasket is ready */
        int max_loops = 10;
        while ((readw(&fec->eth->miigsk_enr) & MIIGSK_ENR_READY) == 0) {
                if (--max_loops <= 0) {
                        printf("WAIT for MII Gasket ready timed out\n");
                        break;
                }
        }
#endif

#ifdef CONFIG_PHYLIB
        {
                /* Start up the PHY */
                int ret = phy_startup(fec->phydev);

                if (ret) {
                        printf("Could not initialize PHY %s\n",
                               fec->phydev->dev->name);
                        return ret;
                }
                speed = fec->phydev->speed;
        }
#elif CONFIG_FEC_FIXED_SPEED
        speed = CONFIG_FEC_FIXED_SPEED;
#else
        miiphy_wait_aneg(edev);
        speed = miiphy_speed(edev->name, fec->phy_id);
        miiphy_duplex(edev->name, fec->phy_id);
#endif

#ifdef FEC_QUIRK_ENET_MAC
        {
                u32 ecr = readl(&fec->eth->ecntrl) & ~FEC_ECNTRL_SPEED;
                u32 rcr = readl(&fec->eth->r_cntrl) & ~FEC_RCNTRL_RMII_10T;
                if (speed == _1000BASET)
                        ecr |= FEC_ECNTRL_SPEED;
                else if (speed != _100BASET)
                        rcr |= FEC_RCNTRL_RMII_10T;
                writel(ecr, &fec->eth->ecntrl);
                writel(rcr, &fec->eth->r_cntrl);
        }
#endif
        debug("%s:Speed=%i\n", __func__, speed);

        /* Enable SmartDMA receive task */
        fec_rx_task_enable(fec);

        udelay(100000);
        return 0;
}

#ifdef CONFIG_DM_ETH
static int fecmxc_init(struct udevice *dev)
#else
static int fec_init(struct eth_device *dev, bd_t *bd)
#endif
{
#ifdef CONFIG_DM_ETH
        struct fec_priv *fec = dev_get_priv(dev);
#else
        struct fec_priv *fec = (struct fec_priv *)dev->priv;
#endif
        uint32_t mib_ptr = (uint32_t)&fec->eth->rmon_t_drop;
        int i;

        /* Initialize MAC address */
#ifdef CONFIG_DM_ETH
        fecmxc_set_hwaddr(dev);
#else
        fec_set_hwaddr(dev);
#endif

        /* Setup transmit descriptors, there are two in total. */
        fec_tbd_init(fec);

        /* Setup receive descriptors. */
        fec_rbd_init(fec, FEC_RBD_NUM, FEC_MAX_PKT_SIZE);

        fec_reg_setup(fec);

        if (fec->xcv_type != SEVENWIRE)
                fec_mii_setspeed(fec->bus->priv);

        /* Set Opcode/Pause Duration Register */
        writel(0x00010020, &fec->eth->op_pause);        /* FIXME 0xffff0020; */
        writel(0x2, &fec->eth->x_wmrk);

        /* Set multicast address filter */
        writel(0x00000000, &fec->eth->gaddr1);
        writel(0x00000000, &fec->eth->gaddr2);

        /* Do not access reserved register for i.MX6UL */
        if (!is_mx6ul() && !is_mx6ull()) {
                /* clear MIB RAM */
                for (i = mib_ptr; i <= mib_ptr + 0xfc; i += 4)
                        writel(0, i);

                /* FIFO receive start register */
                writel(0x520, &fec->eth->r_fstart);
        }

        /* size and address of each buffer */
        writel(FEC_MAX_PKT_SIZE, &fec->eth->emrbr);
        writel((uint32_t)fec->tbd_base, &fec->eth->etdsr);
        writel((uint32_t)fec->rbd_base, &fec->eth->erdsr);

#ifndef CONFIG_PHYLIB
        if (fec->xcv_type != SEVENWIRE)
                miiphy_restart_aneg(dev);
#endif
        fec_open(dev);
        return 0;
}

/**
 * Halt the FEC engine
 * @param[in] dev Our device to handle
 */
#ifdef CONFIG_DM_ETH
static void fecmxc_halt(struct udevice *dev)
#else
static void fec_halt(struct eth_device *dev)
#endif
{
#ifdef CONFIG_DM_ETH
        struct fec_priv *fec = dev_get_priv(dev);
#else
        struct fec_priv *fec = (struct fec_priv *)dev->priv;
#endif
        int counter = 0xffff;

        /* issue graceful stop command to the FEC transmitter if necessary */
        writel(FEC_TCNTRL_GTS | readl(&fec->eth->x_cntrl),
               &fec->eth->x_cntrl);

        debug("eth_halt: wait for stop regs\n");
        /* wait for graceful stop to register */
        while ((counter--) && (!(readl(&fec->eth->ievent) & FEC_IEVENT_GRA)))
                udelay(1);

        /* Disable SmartDMA tasks */
        fec_tx_task_disable(fec);
        fec_rx_task_disable(fec);

        /*
         * Disable the Ethernet Controller
         * Note: this will also reset the BD index counter!
         */
        writel(readl(&fec->eth->ecntrl) & ~FEC_ECNTRL_ETHER_EN,
               &fec->eth->ecntrl);
        fec->rbd_index = 0;
        fec->tbd_index = 0;
        debug("eth_halt: done\n");
}

/**
 * Transmit one frame
 * @param[in] dev Our ethernet device to handle
 * @param[in] packet Pointer to the data to be transmitted
 * @param[in] length Data count in bytes
 * @return 0 on success
 */
#ifdef CONFIG_DM_ETH
static int fecmxc_send(struct udevice *dev, void *packet, int length)
#else
static int fec_send(struct eth_device *dev, void *packet, int length)
#endif
{
        unsigned int status;
        uint32_t size, end;
        uint32_t addr;
        int timeout = FEC_XFER_TIMEOUT;
        int ret = 0;

        /*
         * This routine transmits one frame.  This routine only accepts
         * 6-byte Ethernet addresses.
         */
#ifdef CONFIG_DM_ETH
        struct fec_priv *fec = dev_get_priv(dev);
#else
        struct fec_priv *fec = (struct fec_priv *)dev->priv;
#endif

        /*
         * Check for valid length of data.
         */
        if ((length > 1500) || (length <= 0)) {
                printf("Payload (%d) too large\n", length);
                return -1;
        }

        /*
         * Setup the transmit buffer. We are always using the first buffer for
         * transmission, the second will be empty and only used to stop the DMA
         * engine. We also flush the packet to RAM here to avoid cache trouble.
         */
#ifdef CONFIG_FEC_MXC_SWAP_PACKET
        swap_packet((uint32_t *)packet, length);
#endif

        addr = (uint32_t)packet;
        end = roundup(addr + length, ARCH_DMA_MINALIGN);
        addr &= ~(ARCH_DMA_MINALIGN - 1);
        flush_dcache_range(addr, end);

        writew(length, &fec->tbd_base[fec->tbd_index].data_length);
        writel(addr, &fec->tbd_base[fec->tbd_index].data_pointer);

        /*
         * update BD's status now
         * This block:
         * - is always the last in a chain (means no chain)
         * - should transmitt the CRC
         * - might be the last BD in the list, so the address counter should
         *   wrap (-> keep the WRAP flag)
         */
        status = readw(&fec->tbd_base[fec->tbd_index].status) & FEC_TBD_WRAP;
        status |= FEC_TBD_LAST | FEC_TBD_TC | FEC_TBD_READY;
        writew(status, &fec->tbd_base[fec->tbd_index].status);

        /*
         * Flush data cache. This code flushes both TX descriptors to RAM.
         * After this code, the descriptors will be safely in RAM and we
         * can start DMA.
         */
        size = roundup(2 * sizeof(struct fec_bd), ARCH_DMA_MINALIGN);
        addr = (uint32_t)fec->tbd_base;
        flush_dcache_range(addr, addr + size);

        /*
         * Below we read the DMA descriptor's last four bytes back from the
         * DRAM. This is important in order to make sure that all WRITE
         * operations on the bus that were triggered by previous cache FLUSH
         * have completed.
         *
         * Otherwise, on MX28, it is possible to observe a corruption of the
         * DMA descriptors. Please refer to schematic "Figure 1-2" in MX28RM
         * for the bus structure of MX28. The scenario is as follows:
         *
         * 1) ARM core triggers a series of WRITEs on the AHB_ARB2 bus going
         *    to DRAM due to flush_dcache_range()
         * 2) ARM core writes the FEC registers via AHB_ARB2
         * 3) FEC DMA starts reading/writing from/to DRAM via AHB_ARB3
         *
         * Note that 2) does sometimes finish before 1) due to reordering of
         * WRITE accesses on the AHB bus, therefore triggering 3) before the
         * DMA descriptor is fully written into DRAM. This results in occasional
         * corruption of the DMA descriptor.
         */
        readl(addr + size - 4);

        /* Enable SmartDMA transmit task */
        fec_tx_task_enable(fec);

        /*
         * Wait until frame is sent. On each turn of the wait cycle, we must
         * invalidate data cache to see what's really in RAM. Also, we need
         * barrier here.
         */
        while (--timeout) {
                if (!(readl(&fec->eth->x_des_active) & FEC_X_DES_ACTIVE_TDAR))
                        break;
        }

        if (!timeout) {
                ret = -EINVAL;
                goto out;
        }

        /*
         * The TDAR bit is cleared when the descriptors are all out from TX
         * but on mx6solox we noticed that the READY bit is still not cleared
         * right after TDAR.
         * These are two distinct signals, and in IC simulation, we found that
         * TDAR always gets cleared prior than the READY bit of last BD becomes
         * cleared.
         * In mx6solox, we use a later version of FEC IP. It looks like that
         * this intrinsic behaviour of TDAR bit has changed in this newer FEC
         * version.
         *
         * Fix this by polling the READY bit of BD after the TDAR polling,
         * which covers the mx6solox case and does not harm the other SoCs.
         */
        timeout = FEC_XFER_TIMEOUT;
        while (--timeout) {
                invalidate_dcache_range(addr, addr + size);
                if (!(readw(&fec->tbd_base[fec->tbd_index].status) &
                    FEC_TBD_READY))
                        break;
        }

        if (!timeout)
                ret = -EINVAL;

out:
        debug("fec_send: status 0x%x index %d ret %i\n",
              readw(&fec->tbd_base[fec->tbd_index].status),
              fec->tbd_index, ret);
        /* for next transmission use the other buffer */
        if (fec->tbd_index)
                fec->tbd_index = 0;
        else
                fec->tbd_index = 1;

        return ret;
}

/**
 * Pull one frame from the card
 * @param[in] dev Our ethernet device to handle
 * @return Length of packet read
 */
#ifdef CONFIG_DM_ETH
static int fecmxc_recv(struct udevice *dev, int flags, uchar **packetp)
#else
static int fec_recv(struct eth_device *dev)
#endif
{
#ifdef CONFIG_DM_ETH
        struct fec_priv *fec = dev_get_priv(dev);
#else
        struct fec_priv *fec = (struct fec_priv *)dev->priv;
#endif
        struct fec_bd *rbd = &fec->rbd_base[fec->rbd_index];
        unsigned long ievent;
        int frame_length, len = 0;
        uint16_t bd_status;
        uint32_t addr, size, end;
        int i;
        ALLOC_CACHE_ALIGN_BUFFER(uchar, buff, FEC_MAX_PKT_SIZE);

        /* Check if any critical events have happened */
        ievent = readl(&fec->eth->ievent);
        writel(ievent, &fec->eth->ievent);
        debug("fec_recv: ievent 0x%lx\n", ievent);
        if (ievent & FEC_IEVENT_BABR) {
#ifdef CONFIG_DM_ETH
                fecmxc_halt(dev);
                fecmxc_init(dev);
#else
                fec_halt(dev);
                fec_init(dev, fec->bd);
#endif
                printf("some error: 0x%08lx\n", ievent);
                return 0;
        }
        if (ievent & FEC_IEVENT_HBERR) {
                /* Heartbeat error */
                writel(0x00000001 | readl(&fec->eth->x_cntrl),
                       &fec->eth->x_cntrl);
        }
        if (ievent & FEC_IEVENT_GRA) {
                /* Graceful stop complete */
                if (readl(&fec->eth->x_cntrl) & 0x00000001) {
#ifdef CONFIG_DM_ETH
                        fecmxc_halt(dev);
#else
                        fec_halt(dev);
#endif
                        writel(~0x00000001 & readl(&fec->eth->x_cntrl),
                               &fec->eth->x_cntrl);
#ifdef CONFIG_DM_ETH
                        fecmxc_init(dev);
#else
                        fec_init(dev, fec->bd);
#endif
                }
        }

        /*
         * Read the buffer status. Before the status can be read, the data cache
         * must be invalidated, because the data in RAM might have been changed
         * by DMA. The descriptors are properly aligned to cachelines so there's
         * no need to worry they'd overlap.
         *
         * WARNING: By invalidating the descriptor here, we also invalidate
         * the descriptors surrounding this one. Therefore we can NOT change the
         * contents of this descriptor nor the surrounding ones. The problem is
         * that in order to mark the descriptor as processed, we need to change
         * the descriptor. The solution is to mark the whole cache line when all
         * descriptors in the cache line are processed.
         */
        addr = (uint32_t)rbd;
        addr &= ~(ARCH_DMA_MINALIGN - 1);
        size = roundup(sizeof(struct fec_bd), ARCH_DMA_MINALIGN);
        invalidate_dcache_range(addr, addr + size);

        bd_status = readw(&rbd->status);
        debug("fec_recv: status 0x%x\n", bd_status);

        if (!(bd_status & FEC_RBD_EMPTY)) {
                if ((bd_status & FEC_RBD_LAST) && !(bd_status & FEC_RBD_ERR) &&
                    ((readw(&rbd->data_length) - 4) > 14)) {
                        /* Get buffer address and size */
                        addr = readl(&rbd->data_pointer);
                        frame_length = readw(&rbd->data_length) - 4;
                        /* Invalidate data cache over the buffer */
                        end = roundup(addr + frame_length, ARCH_DMA_MINALIGN);
                        addr &= ~(ARCH_DMA_MINALIGN - 1);
                        invalidate_dcache_range(addr, end);

                        /* Fill the buffer and pass it to upper layers */
#ifdef CONFIG_FEC_MXC_SWAP_PACKET
                        swap_packet((uint32_t *)addr, frame_length);
#endif
                        memcpy(buff, (char *)addr, frame_length);
                        net_process_received_packet(buff, frame_length);
                        len = frame_length;
                } else {
                        if (bd_status & FEC_RBD_ERR)
                                printf("error frame: 0x%08x 0x%08x\n",
                                       addr, bd_status);
                }

                /*
                 * Free the current buffer, restart the engine and move forward
                 * to the next buffer. Here we check if the whole cacheline of
                 * descriptors was already processed and if so, we mark it free
                 * as whole.
                 */
                size = RXDESC_PER_CACHELINE - 1;
                if ((fec->rbd_index & size) == size) {
                        i = fec->rbd_index - size;
                        addr = (uint32_t)&fec->rbd_base[i];
                        for (; i <= fec->rbd_index ; i++) {
                                fec_rbd_clean(i == (FEC_RBD_NUM - 1),
                                              &fec->rbd_base[i]);
                        }
                        flush_dcache_range(addr,
                                           addr + ARCH_DMA_MINALIGN);
                }

                fec_rx_task_enable(fec);
                fec->rbd_index = (fec->rbd_index + 1) % FEC_RBD_NUM;
        }
        debug("fec_recv: stop\n");

        return len;
}

static void fec_set_dev_name(char *dest, int dev_id)
{
        sprintf(dest, (dev_id == -1) ? "FEC" : "FEC%i", dev_id);
}

static int fec_alloc_descs(struct fec_priv *fec)
{
        unsigned int size;
        int i;
        uint8_t *data;

        /* Allocate TX descriptors. */
        size = roundup(2 * sizeof(struct fec_bd), ARCH_DMA_MINALIGN);
        fec->tbd_base = memalign(ARCH_DMA_MINALIGN, size);
        if (!fec->tbd_base)
                goto err_tx;

        /* Allocate RX descriptors. */
        size = roundup(FEC_RBD_NUM * sizeof(struct fec_bd), ARCH_DMA_MINALIGN);
        fec->rbd_base = memalign(ARCH_DMA_MINALIGN, size);
        if (!fec->rbd_base)
                goto err_rx;

        memset(fec->rbd_base, 0, size);

        /* Allocate RX buffers. */

        /* Maximum RX buffer size. */
        size = roundup(FEC_MAX_PKT_SIZE, FEC_DMA_RX_MINALIGN);
        for (i = 0; i < FEC_RBD_NUM; i++) {
                data = memalign(FEC_DMA_RX_MINALIGN, size);
                if (!data) {
                        printf("%s: error allocating rxbuf %d\n", __func__, i);
                        goto err_ring;
                }

                memset(data, 0, size);

                fec->rbd_base[i].data_pointer = (uint32_t)data;
                fec->rbd_base[i].status = FEC_RBD_EMPTY;
                fec->rbd_base[i].data_length = 0;
                /* Flush the buffer to memory. */
                flush_dcache_range((uint32_t)data, (uint32_t)data + size);
        }

        /* Mark the last RBD to close the ring. */
        fec->rbd_base[i - 1].status = FEC_RBD_WRAP | FEC_RBD_EMPTY;

        fec->rbd_index = 0;
        fec->tbd_index = 0;

        return 0;

err_ring:
        for (; i >= 0; i--)
                free((void *)fec->rbd_base[i].data_pointer);
        free(fec->rbd_base);
err_rx:
        free(fec->tbd_base);
err_tx:
        return -ENOMEM;
}

static void fec_free_descs(struct fec_priv *fec)
{
        int i;

        for (i = 0; i < FEC_RBD_NUM; i++)
                free((void *)fec->rbd_base[i].data_pointer);
        free(fec->rbd_base);
        free(fec->tbd_base);
}

struct mii_dev *fec_get_miibus(uint32_t base_addr, int dev_id)
{
        struct ethernet_regs *eth = (struct ethernet_regs *)base_addr;
        struct mii_dev *bus;
        int ret;

        bus = mdio_alloc();
        if (!bus) {
                printf("mdio_alloc failed\n");
                return NULL;
        }
        bus->read = fec_phy_read;
        bus->write = fec_phy_write;
        bus->priv = eth;
        fec_set_dev_name(bus->name, dev_id);

        ret = mdio_register(bus);
        if (ret) {
                printf("mdio_register failed\n");
                free(bus);
                return NULL;
        }
        fec_mii_setspeed(eth);
        return bus;
}

#ifndef CONFIG_DM_ETH
#ifdef CONFIG_PHYLIB
int fec_probe(bd_t *bd, int dev_id, uint32_t base_addr,
                struct mii_dev *bus, struct phy_device *phydev)
#else
static int fec_probe(bd_t *bd, int dev_id, uint32_t base_addr,
                struct mii_dev *bus, int phy_id)
#endif
{
        struct eth_device *edev;
        struct fec_priv *fec;
        unsigned char ethaddr[6];
        char mac[16];
        uint32_t start;
        int ret = 0;

        /* create and fill edev struct */
        edev = (struct eth_device *)malloc(sizeof(struct eth_device));
        if (!edev) {
                puts("fec_mxc: not enough malloc memory for eth_device\n");
                ret = -ENOMEM;
                goto err1;
        }

        fec = (struct fec_priv *)malloc(sizeof(struct fec_priv));
        if (!fec) {
                puts("fec_mxc: not enough malloc memory for fec_priv\n");
                ret = -ENOMEM;
                goto err2;
        }

        memset(edev, 0, sizeof(*edev));
        memset(fec, 0, sizeof(*fec));

        ret = fec_alloc_descs(fec);
        if (ret)
                goto err3;

        edev->priv = fec;
        edev->init = fec_init;
        edev->send = fec_send;
        edev->recv = fec_recv;
        edev->halt = fec_halt;
        edev->write_hwaddr = fec_set_hwaddr;

        fec->eth = (struct ethernet_regs *)base_addr;
        fec->bd = bd;

        fec->xcv_type = CONFIG_FEC_XCV_TYPE;

        /* Reset chip. */
        writel(readl(&fec->eth->ecntrl) | FEC_ECNTRL_RESET, &fec->eth->ecntrl);
        start = get_timer(0);
        while (readl(&fec->eth->ecntrl) & FEC_ECNTRL_RESET) {
                if (get_timer(start) > (CONFIG_SYS_HZ * 5)) {
                        printf("FEC MXC: Timeout resetting chip\n");
                        goto err4;
                }
                udelay(10);
        }

        fec_reg_setup(fec);
        fec_set_dev_name(edev->name, dev_id);
        fec->dev_id = (dev_id == -1) ? 0 : dev_id;
        fec->bus = bus;
        fec_mii_setspeed(bus->priv);
#ifdef CONFIG_PHYLIB
        fec->phydev = phydev;
        phy_connect_dev(phydev, edev);
        /* Configure phy */
        phy_config(phydev);
#else
        fec->phy_id = phy_id;
#endif
        eth_register(edev);
        /* only support one eth device, the index number pointed by dev_id */
        edev->index = fec->dev_id;

        if (fec_get_hwaddr(fec->dev_id, ethaddr) == 0) {
                debug("got MAC%d address from fuse: %pM\n", fec->dev_id, ethaddr);
                memcpy(edev->enetaddr, ethaddr, 6);
                if (fec->dev_id)
                        sprintf(mac, "eth%daddr", fec->dev_id);
                else
                        strcpy(mac, "ethaddr");
                if (!env_get(mac))
                        eth_env_set_enetaddr(mac, ethaddr);
        }
        return ret;
err4:
        fec_free_descs(fec);
err3:
        free(fec);
err2:
        free(edev);
err1:
        return ret;
}

int fecmxc_initialize_multi(bd_t *bd, int dev_id, int phy_id, uint32_t addr)
{
        uint32_t base_mii;
        struct mii_dev *bus = NULL;
#ifdef CONFIG_PHYLIB
        struct phy_device *phydev = NULL;
#endif
        int ret;

#ifdef CONFIG_MX28
        /*
         * The i.MX28 has two ethernet interfaces, but they are not equal.
         * Only the first one can access the MDIO bus.
         */
        base_mii = MXS_ENET0_BASE;
#else
        base_mii = addr;
#endif
        debug("eth_init: fec_probe(bd, %i, %i) @ %08x\n", dev_id, phy_id, addr);
        bus = fec_get_miibus(base_mii, dev_id);
        if (!bus)
                return -ENOMEM;
#ifdef CONFIG_PHYLIB
        phydev = phy_find_by_mask(bus, 1 << phy_id, PHY_INTERFACE_MODE_RGMII);
        if (!phydev) {
                mdio_unregister(bus);
                free(bus);
                return -ENOMEM;
        }
        ret = fec_probe(bd, dev_id, addr, bus, phydev);
#else
        ret = fec_probe(bd, dev_id, addr, bus, phy_id);
#endif
        if (ret) {
#ifdef CONFIG_PHYLIB
                free(phydev);
#endif
                mdio_unregister(bus);
                free(bus);
        }
        return ret;
}

#ifdef CONFIG_FEC_MXC_PHYADDR
int fecmxc_initialize(bd_t *bd)
{
        return fecmxc_initialize_multi(bd, -1, CONFIG_FEC_MXC_PHYADDR,
                        IMX_FEC_BASE);
}
#endif

#ifndef CONFIG_PHYLIB
int fecmxc_register_mii_postcall(struct eth_device *dev, int (*cb)(int))
{
        struct fec_priv *fec = (struct fec_priv *)dev->priv;
        fec->mii_postcall = cb;
        return 0;
}
#endif

#else

static int fecmxc_read_rom_hwaddr(struct udevice *dev)
{
        struct fec_priv *priv = dev_get_priv(dev);
        struct eth_pdata *pdata = dev_get_platdata(dev);

        return fec_get_hwaddr(priv->dev_id, pdata->enetaddr);
}

static const struct eth_ops fecmxc_ops = {
        .start                  = fecmxc_init,
        .send                   = fecmxc_send,
        .recv                   = fecmxc_recv,
        .stop                   = fecmxc_halt,
        .write_hwaddr           = fecmxc_set_hwaddr,
        .read_rom_hwaddr        = fecmxc_read_rom_hwaddr,
};

static int fec_phy_init(struct fec_priv *priv, struct udevice *dev)
{
        struct phy_device *phydev;
        int mask = 0xffffffff;

#ifdef CONFIG_PHYLIB
        mask = 1 << CONFIG_FEC_MXC_PHYADDR;
#endif

        phydev = phy_find_by_mask(priv->bus, mask, priv->interface);
        if (!phydev)
                return -ENODEV;

        phy_connect_dev(phydev, dev);

        priv->phydev = phydev;
        phy_config(phydev);

        return 0;
}

static int fecmxc_probe(struct udevice *dev)
{
        struct eth_pdata *pdata = dev_get_platdata(dev);
        struct fec_priv *priv = dev_get_priv(dev);
        struct mii_dev *bus = NULL;
        int dev_id = -1;
        uint32_t start;
        int ret;

        ret = fec_alloc_descs(priv);
        if (ret)
                return ret;

        /* Reset chip. */
        writel(readl(&priv->eth->ecntrl) | FEC_ECNTRL_RESET,
               &priv->eth->ecntrl);
        start = get_timer(0);
        while (readl(&priv->eth->ecntrl) & FEC_ECNTRL_RESET) {
                if (get_timer(start) > (CONFIG_SYS_HZ * 5)) {
                        printf("FEC MXC: Timeout reseting chip\n");
                        goto err_timeout;
                }
                udelay(10);
        }

        fec_reg_setup(priv);
        priv->dev_id = (dev_id == -1) ? 0 : dev_id;

        bus = fec_get_miibus(dev, dev_id);
        if (!bus) {
                ret = -ENOMEM;
                goto err_mii;
        }

        priv->bus = bus;
        priv->xcv_type = CONFIG_FEC_XCV_TYPE;
        priv->interface = pdata->phy_interface;
        ret = fec_phy_init(priv, dev);
        if (ret)
                goto err_phy;

        return 0;

err_timeout:
        free(priv->phydev);
err_phy:
        mdio_unregister(bus);
        free(bus);
err_mii:
        fec_free_descs(priv);
        return ret;
}

static int fecmxc_remove(struct udevice *dev)
{
        struct fec_priv *priv = dev_get_priv(dev);

        free(priv->phydev);
        fec_free_descs(priv);
        mdio_unregister(priv->bus);
        mdio_free(priv->bus);

        return 0;
}

static int fecmxc_ofdata_to_platdata(struct udevice *dev)
{
        struct eth_pdata *pdata = dev_get_platdata(dev);
        struct fec_priv *priv = dev_get_priv(dev);
        const char *phy_mode;

        pdata->iobase = (phys_addr_t)devfdt_get_addr(dev);
        priv->eth = (struct ethernet_regs *)pdata->iobase;

        pdata->phy_interface = -1;
        phy_mode = fdt_getprop(gd->fdt_blob, dev_of_offset(dev), "phy-mode",
                               NULL);
        if (phy_mode)
                pdata->phy_interface = phy_get_interface_by_name(phy_mode);
        if (pdata->phy_interface == -1) {
                debug("%s: Invalid PHY interface '%s'\n", __func__, phy_mode);
                return -EINVAL;
        }

        /* TODO
         * Need to get the reset-gpio and related properties from DT
         * and implemet the enet reset code on .probe call
         */

        return 0;
}

static const struct udevice_id fecmxc_ids[] = {
        { .compatible = "fsl,imx6q-fec" },
        { }
};

U_BOOT_DRIVER(fecmxc_gem) = {
        .name   = "fecmxc",
        .id     = UCLASS_ETH,
        .of_match = fecmxc_ids,
        .ofdata_to_platdata = fecmxc_ofdata_to_platdata,
        .probe  = fecmxc_probe,
        .remove = fecmxc_remove,
        .ops    = &fecmxc_ops,
        .priv_auto_alloc_size = sizeof(struct fec_priv),
        .platdata_auto_alloc_size = sizeof(struct eth_pdata),
};
#endif