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nicstarmac.c

/*
 * this file included by nicstar.c
 */

/*
 * nicstarmac.c
 * Read this ForeRunner's MAC address from eprom/eeprom
 */

#include <linux/kernel.h>

typedef void __iomem *virt_addr_t;

#define CYCLE_DELAY 5

/* This was the original definition
#define osp_MicroDelay(microsec) \
    do { int _i = 4*microsec; while (--_i > 0) { __SLOW_DOWN_IO; }} while (0)
*/
#define osp_MicroDelay(microsec) {unsigned long useconds = (microsec); \
                                  udelay((useconds));}


/* The following tables represent the timing diagrams found in
 * the Data Sheet for the Xicor X25020 EEProm.  The #defines below
 * represent the bits in the NICStAR's General Purpose register
 * that must be toggled for the corresponding actions on the EEProm
 * to occur.
 */

/* Write Data To EEProm from SI line on rising edge of CLK */
/* Read Data From EEProm on falling edge of CLK */

#define CS_HIGH         0x0002            /* Chip select high */
#define CS_LOW          0x0000            /* Chip select low (active low)*/
#define CLK_HIGH  0x0004            /* Clock high */
#define CLK_LOW         0x0000            /* Clock low  */
#define SI_HIGH         0x0001            /* Serial input data high */
#define SI_LOW          0x0000            /* Serial input data low */

/* Read Status Register = 0000 0101b */
#if 0
static u_int32_t rdsrtab[] =
{
    CS_HIGH | CLK_HIGH, 
    CS_LOW | CLK_LOW, 
    CLK_HIGH,             /* 0 */
    CLK_LOW, 
    CLK_HIGH,             /* 0 */
    CLK_LOW, 
    CLK_HIGH,             /* 0 */
    CLK_LOW,
    CLK_HIGH,             /* 0 */
    CLK_LOW, 
    CLK_HIGH,             /* 0 */
    CLK_LOW | SI_HIGH, 
    CLK_HIGH | SI_HIGH,   /* 1 */
    CLK_LOW | SI_LOW, 
    CLK_HIGH,             /* 0 */
    CLK_LOW | SI_HIGH, 
    CLK_HIGH | SI_HIGH   /* 1 */
};
#endif  /*  0  */


/* Read from EEPROM = 0000 0011b */
static u_int32_t readtab[] =
{
    /*
    CS_HIGH | CLK_HIGH, 
    */
    CS_LOW | CLK_LOW, 
    CLK_HIGH,             /* 0 */
    CLK_LOW, 
    CLK_HIGH,             /* 0 */
    CLK_LOW, 
    CLK_HIGH,             /* 0 */
    CLK_LOW,
    CLK_HIGH,             /* 0 */
    CLK_LOW, 
    CLK_HIGH,             /* 0 */
    CLK_LOW, 
    CLK_HIGH,             /* 0 */
    CLK_LOW | SI_HIGH, 
    CLK_HIGH | SI_HIGH,   /* 1 */
    CLK_LOW | SI_HIGH, 
    CLK_HIGH | SI_HIGH    /* 1 */
};


/* Clock to read from/write to the eeprom */
static u_int32_t clocktab[] =
{     
    CLK_LOW,
    CLK_HIGH,
    CLK_LOW, 
    CLK_HIGH,
    CLK_LOW,
    CLK_HIGH,
    CLK_LOW, 
    CLK_HIGH,
    CLK_LOW, 
    CLK_HIGH,
    CLK_LOW, 
    CLK_HIGH, 
    CLK_LOW, 
    CLK_HIGH,
    CLK_LOW, 
    CLK_HIGH,
    CLK_LOW 
};


#define NICSTAR_REG_WRITE(bs, reg, val) \
      while ( readl(bs + STAT) & 0x0200 ) ; \
      writel((val),(base)+(reg))
#define NICSTAR_REG_READ(bs, reg) \
      readl((base)+(reg))
#define NICSTAR_REG_GENERAL_PURPOSE GP

/*
 * This routine will clock the Read_Status_reg function into the X2520
 * eeprom, then pull the result from bit 16 of the NicSTaR's General Purpose 
 * register.  
 */
#if 0
u_int32_t
nicstar_read_eprom_status( virt_addr_t base )
{
   u_int32_t      val;
   u_int32_t      rbyte;
   int32_t  i, j;

   /* Send read instruction */
   val = NICSTAR_REG_READ( base, NICSTAR_REG_GENERAL_PURPOSE ) & 0xFFFFFFF0;

   for (i=0; i<ARRAY_SIZE(rdsrtab); i++)
   {
      NICSTAR_REG_WRITE( base, NICSTAR_REG_GENERAL_PURPOSE,
            (val | rdsrtab[i]) );
        osp_MicroDelay( CYCLE_DELAY );
   }

   /* Done sending instruction - now pull data off of bit 16, MSB first */
   /* Data clocked out of eeprom on falling edge of clock */

   rbyte = 0;
   for (i=7, j=0; i>=0; i--)
   {
      NICSTAR_REG_WRITE( base, NICSTAR_REG_GENERAL_PURPOSE,
            (val | clocktab[j++]) );
        rbyte |= (((NICSTAR_REG_READ( base, NICSTAR_REG_GENERAL_PURPOSE)
                  & 0x00010000) >> 16) << i);
      NICSTAR_REG_WRITE( base, NICSTAR_REG_GENERAL_PURPOSE,
            (val | clocktab[j++]) );
        osp_MicroDelay( CYCLE_DELAY );
   }
   NICSTAR_REG_WRITE( base, NICSTAR_REG_GENERAL_PURPOSE, 2 );
   osp_MicroDelay( CYCLE_DELAY );
   return rbyte;
}
#endif  /*  0  */


/*
 * This routine will clock the Read_data function into the X2520
 * eeprom, followed by the address to read from, through the NicSTaR's General
 * Purpose register.  
 */
 
static u_int8_t 
read_eprom_byte(virt_addr_t base, u_int8_t offset)
{
   u_int32_t val = 0;
   int i,j=0;
   u_int8_t tempread = 0;

   val = NICSTAR_REG_READ( base, NICSTAR_REG_GENERAL_PURPOSE ) & 0xFFFFFFF0;

   /* Send READ instruction */
   for (i=0; i<ARRAY_SIZE(readtab); i++)
   {
      NICSTAR_REG_WRITE( base, NICSTAR_REG_GENERAL_PURPOSE,
            (val | readtab[i]) );
        osp_MicroDelay( CYCLE_DELAY );
   }

   /* Next, we need to send the byte address to read from */
   for (i=7; i>=0; i--)
   {
      NICSTAR_REG_WRITE( base, NICSTAR_REG_GENERAL_PURPOSE,
                  (val | clocktab[j++] | ((offset >> i) & 1) ) );
      osp_MicroDelay(CYCLE_DELAY);
      NICSTAR_REG_WRITE( base, NICSTAR_REG_GENERAL_PURPOSE,
                  (val | clocktab[j++] | ((offset >> i) & 1) ) );
      osp_MicroDelay( CYCLE_DELAY );
   }

   j = 0;
   
   /* Now, we can read data from the eeprom by clocking it in */
   for (i=7; i>=0; i--)
   {
      NICSTAR_REG_WRITE( base, NICSTAR_REG_GENERAL_PURPOSE,
                  (val | clocktab[j++]) );
      osp_MicroDelay( CYCLE_DELAY );
      tempread |= (((NICSTAR_REG_READ( base, NICSTAR_REG_GENERAL_PURPOSE )
            & 0x00010000) >> 16) << i);
      NICSTAR_REG_WRITE( base, NICSTAR_REG_GENERAL_PURPOSE,
                  (val | clocktab[j++]) );
      osp_MicroDelay( CYCLE_DELAY );
   }

   NICSTAR_REG_WRITE( base, NICSTAR_REG_GENERAL_PURPOSE, 2 );
   osp_MicroDelay( CYCLE_DELAY );
   return tempread;
}


static void
nicstar_init_eprom( virt_addr_t base )
{
    u_int32_t val;

    /*
     * turn chip select off
     */
    val = NICSTAR_REG_READ(base, NICSTAR_REG_GENERAL_PURPOSE) & 0xFFFFFFF0;

    NICSTAR_REG_WRITE(base, NICSTAR_REG_GENERAL_PURPOSE,
      (val | CS_HIGH | CLK_HIGH));
    osp_MicroDelay( CYCLE_DELAY );

    NICSTAR_REG_WRITE(base, NICSTAR_REG_GENERAL_PURPOSE,
      (val | CS_HIGH | CLK_LOW));
    osp_MicroDelay( CYCLE_DELAY );

    NICSTAR_REG_WRITE(base, NICSTAR_REG_GENERAL_PURPOSE,
      (val | CS_HIGH | CLK_HIGH));
    osp_MicroDelay( CYCLE_DELAY );

    NICSTAR_REG_WRITE(base, NICSTAR_REG_GENERAL_PURPOSE,
      (val | CS_HIGH | CLK_LOW));
    osp_MicroDelay( CYCLE_DELAY );
}


/*
 * This routine will be the interface to the ReadPromByte function
 * above.
 */ 

static void
nicstar_read_eprom(
    virt_addr_t   base,
    u_int8_t      prom_offset,
    u_int8_t      *buffer,
    u_int32_t     nbytes )
{
    u_int         i;
    
    for (i=0; i<nbytes; i++)
    {
      buffer[i] = read_eprom_byte( base, prom_offset );
      ++prom_offset;
      osp_MicroDelay( CYCLE_DELAY );
    }
}


/*
void osp_MicroDelay(int x) {
    
}
*/


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