/*
 * (C) Copyright 2003
 * Gleb Natapov <gnatapov@mrv.com>
 * Some bits are taken from linux driver writen by adrian@humboldt.co.uk
 *
 * Hardware I2C driver for MPC107 PCI bridge.
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <common.h>

#undef I2CDBG

#ifdef CONFIG_HARD_I2C
#include <i2c.h>

#define TIMEOUT (CONFIG_SYS_HZ/4)

#define I2C_Addr ((unsigned *)(CONFIG_SYS_EUMB_ADDR + 0x3000))

#define I2CADR &I2C_Addr[0]
#define I2CFDR  &I2C_Addr[1]
#define I2CCCR  &I2C_Addr[2]
#define I2CCSR  &I2C_Addr[3]
#define I2CCDR  &I2C_Addr[4]

#define MPC107_CCR_MEN  0x80
#define MPC107_CCR_MIEN 0x40
#define MPC107_CCR_MSTA 0x20
#define MPC107_CCR_MTX  0x10
#define MPC107_CCR_TXAK 0x08
#define MPC107_CCR_RSTA 0x04

#define MPC107_CSR_MCF  0x80
#define MPC107_CSR_MAAS 0x40
#define MPC107_CSR_MBB  0x20
#define MPC107_CSR_MAL  0x10
#define MPC107_CSR_SRW  0x04
#define MPC107_CSR_MIF  0x02
#define MPC107_CSR_RXAK 0x01

#define I2C_READ  1
#define I2C_WRITE 0

/* taken from linux include/asm-ppc/io.h */
inline unsigned in_le32 (volatile unsigned *addr)
{
        unsigned ret;

        __asm__ __volatile__ ("lwbrx %0,0,%1;\n"
                              "twi 0,%0,0;\n"
                              "isync":"=r" (ret): "r" (addr), "m" (*addr));
        return ret;
}

inline void out_le32 (volatile unsigned *addr, int val)
{
        __asm__ __volatile__ ("stwbrx %1,0,%2; eieio":"=m" (*addr):"r" (val),
                              "r" (addr));
}

#define writel(val, addr) out_le32(addr, val)
#define readl(addr) in_le32(addr)

void i2c_init (int speed, int slaveadd)
{
        /* stop I2C controller */
        writel (0x0, I2CCCR);
        /* set clock */
        writel (0x1020, I2CFDR);
        /* write slave address */
        writel (slaveadd, I2CADR);
        /* clear status register */
        writel (0x0, I2CCSR);
        /* start I2C controller */
        writel (MPC107_CCR_MEN, I2CCCR);

        return;
}

static __inline__ int i2c_wait4bus (void)
{
        ulong timeval = get_timer (0);

        while (readl (I2CCSR) & MPC107_CSR_MBB)
                if (get_timer (timeval) > TIMEOUT)
                        return -1;

        return 0;
}

static __inline__ int i2c_wait (int write)
{
        u32 csr;
        ulong timeval = get_timer (0);

        do {
                csr = readl (I2CCSR);

                if (!(csr & MPC107_CSR_MIF))
                        continue;

                writel (0x0, I2CCSR);

                if (csr & MPC107_CSR_MAL) {
#ifdef I2CDBG
                        printf ("i2c_wait: MAL\n");
#endif
                        return -1;
                }

                if (!(csr & MPC107_CSR_MCF)) {
#ifdef I2CDBG
                        printf ("i2c_wait: unfinished\n");
#endif
                        return -1;
                }

                if (write == I2C_WRITE && (csr & MPC107_CSR_RXAK)) {
#ifdef I2CDBG
                        printf ("i2c_wait: No RXACK\n");
#endif
                        return -1;
                }

                return 0;
        } while (get_timer (timeval) < TIMEOUT);

#ifdef I2CDBG
        printf ("i2c_wait: timed out\n");
#endif
        return -1;
}

static __inline__ int i2c_write_addr (u8 dev, u8 dir, int rsta)
{
        writel (MPC107_CCR_MEN | MPC107_CCR_MSTA | MPC107_CCR_MTX |
                (rsta ? MPC107_CCR_RSTA : 0), I2CCCR);

        writel ((dev << 1) | dir, I2CCDR);

        if (i2c_wait (I2C_WRITE) < 0)
                return 0;

        return 1;
}

static __inline__ int __i2c_write (u8 * data, int length)
{
        int i;

        writel (MPC107_CCR_MEN | MPC107_CCR_MSTA | MPC107_CCR_MTX, I2CCCR);

        for (i = 0; i < length; i++) {
                writel (data[i], I2CCDR);

                if (i2c_wait (I2C_WRITE) < 0)
                        break;
        }

        return i;
}

static __inline__ int __i2c_read (u8 * data, int length)
{
        int i;

        writel (MPC107_CCR_MEN | MPC107_CCR_MSTA |
                ((length == 1) ? MPC107_CCR_TXAK : 0), I2CCCR);

        /* dummy read */
        readl (I2CCDR);

        for (i = 0; i < length; i++) {
                if (i2c_wait (I2C_READ) < 0)
                        break;

                /* Generate ack on last next to last byte */
                if (i == length - 2)
                        writel (MPC107_CCR_MEN | MPC107_CCR_MSTA |
                                MPC107_CCR_TXAK, I2CCCR);

                /* Generate stop on last byte */
                if (i == length - 1)
                        writel (MPC107_CCR_MEN | MPC107_CCR_TXAK, I2CCCR);

                data[i] = readl (I2CCDR);
        }

        return i;
}

int i2c_read (u8 dev, uint addr, int alen, u8 * data, int length)
{
        int i = 0;
        u8 *a = (u8 *) & addr;

        if (i2c_wait4bus () < 0)
                goto exit;

        if (i2c_write_addr (dev, I2C_WRITE, 0) == 0)
                goto exit;

        if (__i2c_write (&a[4 - alen], alen) != alen)
                goto exit;

        if (i2c_write_addr (dev, I2C_READ, 1) == 0)
                goto exit;

        i = __i2c_read (data, length);

exit:
        writel (MPC107_CCR_MEN, I2CCCR);

        return !(i == length);
}

int i2c_write (u8 dev, uint addr, int alen, u8 * data, int length)
{
        int i = 0;
        u8 *a = (u8 *) & addr;

        if (i2c_wait4bus () < 0)
                goto exit;

        if (i2c_write_addr (dev, I2C_WRITE, 0) == 0)
                goto exit;

        if (__i2c_write (&a[4 - alen], alen) != alen)
                goto exit;

        i = __i2c_write (data, length);

exit:
        writel (MPC107_CCR_MEN, I2CCCR);

        return !(i == length);
}

int i2c_probe (uchar chip)
{
        int tmp;

        /*
         * Try to read the first location of the chip.  The underlying
         * driver doesn't appear to support sending just the chip address
         * and looking for an <ACK> back.
         */
        udelay (10000);
        return i2c_read (chip, 0, 1, (uchar *) &tmp, 1);
}

#endif /* CONFIG_HARD_I2C */