cpqfctsi2c.c

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/* Copyright(c) 2000, Compaq Computer Corporation 
 * Fibre Channel Host Bus Adapter 
 * 64-bit, 66MHz PCI 
 * Originally developed and tested on:
 * (front): [chip] Tachyon TS HPFC-5166A/1.2  L2C1090 ...
 *          SP# P225CXCBFIEL6T, Rev XC
 *          SP# 161290-001, Rev XD
 * (back): Board No. 010008-001 A/W Rev X5, FAB REV X5
 *
 * 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, 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.
 * Written by Don Zimmerman
*/
// These functions control the NVRAM I2C hardware on 
// non-intelligent Fibre Host Adapters.
// The primary purpose is to read the HBA's NVRAM to get adapter's 
// manufactured WWN to copy into Tachyon chip registers
// Orignal source author unknown

#include <linux/types.h>
enum boolean { FALSE, TRUE } ;


#ifndef UCHAR
typedef __u8 UCHAR;
#endif
#ifndef BOOLEAN
typedef __u8 BOOLEAN;
#endif
#ifndef USHORT
typedef __u16 USHORT;
#endif
#ifndef ULONG
typedef __u32 ULONG;
#endif


#include <linux/string.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <asm/io.h>  // struct pt_regs for IRQ handler & Port I/O

#include "cpqfcTSchip.h"

static void tl_i2c_tx_byte( void* GPIOout, UCHAR data );
/*static BOOLEAN tl_write_i2c_page_portion( void* GPIOin, void* GPIOout,
  USHORT startOffset,  // e.g. 0x2f for WWN start
  USHORT count,
  UCHAR *buf );
*/

//
// Tachlite GPIO2, GPIO3 (I2C) DEFINES
// The NVRAM chip NM24C03 defines SCL (serial clock) and SDA (serial data)
// GPIO2 drives SDA, and GPIO3 drives SCL
// 
// Since Tachlite inverts the state of the GPIO 0-3 outputs, SET writes 0
// and clear writes 1. The input lines (read in TL status) is NOT inverted
// This really helps confuse the code and debugging.

#define SET_DATA_HI  0x0
#define SET_DATA_LO  0x8
#define SET_CLOCK_HI 0x0
#define SET_CLOCK_LO 0x4

#define SENSE_DATA_HI  0x8
#define SENSE_DATA_LO  0x0
#define SENSE_CLOCK_HI 0x4
#define SENSE_CLOCK_LO 0x0

#define SLAVE_READ_ADDRESS    0xA1
#define SLAVE_WRITE_ADDRESS   0xA0
					      

static void i2c_delay(ULONG mstime);
static void tl_i2c_clock_pulse( UCHAR , void* GPIOout);
static UCHAR tl_read_i2c_data( void* );


//-----------------------------------------------------------------------------
//
//      Name:   I2C_RX_ACK
//
//      This routine receives an acknowledge over the I2C bus.
//
//-----------------------------------------------------------------------------
static unsigned short tl_i2c_rx_ack( void* GPIOin, void* GPIOout )
{
  unsigned long value;

	// do clock pulse, let data line float high
  tl_i2c_clock_pulse( SET_DATA_HI, GPIOout );

	// slave must drive data low for acknowledge
  value = tl_read_i2c_data( GPIOin);
  if (value & SENSE_DATA_HI )
    return( FALSE );

  return( TRUE );
}
//-----------------------------------------------------------------------------
//
//      Name:   READ_I2C_REG
//
//      This routine reads the I2C control register using the global
//      IO address stored in gpioreg.
//
//-----------------------------------------------------------------------------
static UCHAR tl_read_i2c_data( void* gpioreg )
{
  return( (UCHAR)(readl( gpioreg ) & 0x08L) ); // GPIO3
}
//-----------------------------------------------------------------------------
//
//      Name:   WRITE_I2C_REG
//
//      This routine writes the I2C control register using the global
//      IO address stored in gpioreg.
//      In Tachlite, we don't want to modify other bits in TL Control reg.
//
//-----------------------------------------------------------------------------
static void tl_write_i2c_reg( void* gpioregOUT, UCHAR value )
{
  ULONG  temp;

	// First read the register and clear out the old bits
  temp = readl( gpioregOUT ) & 0xfffffff3L;

	// Now or in the new data and send it back out
  writel( temp | value, gpioregOUT);
}
//-----------------------------------------------------------------------------
//
//      Name:   I2C_TX_START
//
//      This routine transmits a start condition over the I2C bus.
//      1. Set SCL (clock, GPIO2) HIGH, set SDA (data, GPIO3) HIGH,
//      wait 5us to stabilize.
//      2. With SCL still HIGH, drive SDA low.  The low transition marks
//         the start condition to NM24Cxx (the chip)
//      NOTE! In TL control reg., output 1 means chip sees LOW
//
//-----------------------------------------------------------------------------
static unsigned short tl_i2c_tx_start( void* GPIOin, void* GPIOout )
{
  unsigned short i;
  ULONG value;

  if ( !(tl_read_i2c_data(GPIOin) & SENSE_DATA_HI))
  {
    // start with clock high, let data float high
    tl_write_i2c_reg(  GPIOout, SET_DATA_HI | SET_CLOCK_HI );

    // keep sending clock pulses if slave is driving data line
    for (i = 0; i < 10; i++)
    {
      tl_i2c_clock_pulse( SET_DATA_HI, GPIOout );

      if ( tl_read_i2c_data(GPIOin) & SENSE_DATA_HI )
	break;
    }

		// if he's still driving data low after 10 clocks, abort
    value = tl_read_i2c_data( GPIOin ); // read status
    if (!(value & 0x08) )
      return( FALSE );
  }


	// To START, bring data low while clock high
  tl_write_i2c_reg(  GPIOout, SET_CLOCK_HI | SET_DATA_LO );

  i2c_delay(0);

  return( TRUE );                           // TX start successful
}
//-----------------------------------------------------------------------------
//
//      Name:   I2C_TX_STOP
//
//      This routine transmits a stop condition over the I2C bus.
//
//-----------------------------------------------------------------------------

static unsigned short tl_i2c_tx_stop( void* GPIOin, void* GPIOout )
{
  int i;

  for (i = 0; i < 10; i++) 
  {
  // Send clock pulse, drive data line low
    tl_i2c_clock_pulse( SET_DATA_LO, GPIOout );

  // To STOP, bring data high while clock high
    tl_write_i2c_reg(  GPIOout, SET_DATA_HI | SET_CLOCK_HI );

  // Give the data line time to float high
    i2c_delay(0);

  // If slave is driving data line low, there's a problem; retry
    if ( tl_read_i2c_data(GPIOin) & SENSE_DATA_HI )
      return( TRUE );  // TX STOP successful!
  }

  return( FALSE );                      // error
}
//-----------------------------------------------------------------------------
//
//      Name:   I2C_TX_uchar
//
//      This routine transmits a byte across the I2C bus.
//
//-----------------------------------------------------------------------------
static void tl_i2c_tx_byte( void* GPIOout, UCHAR data )
{
  UCHAR bit;

  for (bit = 0x80; bit; bit >>= 1)
  {
    if( data & bit )
      tl_i2c_clock_pulse( (UCHAR)SET_DATA_HI, GPIOout);
    else
      tl_i2c_clock_pulse( (UCHAR)SET_DATA_LO, GPIOout);
  }  
}
//-----------------------------------------------------------------------------
//
//      Name:   I2C_RX_uchar
//
//      This routine receives a byte across the I2C bus.
//
//-----------------------------------------------------------------------------
static UCHAR tl_i2c_rx_byte( void* GPIOin, void* GPIOout )
{
  UCHAR bit;
  UCHAR data = 0;


  for (bit = 0x80; bit; bit >>= 1) {
    // do clock pulse, let data line float high
    tl_i2c_clock_pulse( SET_DATA_HI, GPIOout );

    // read data line
    if ( tl_read_i2c_data( GPIOin) & 0x08 )
      data |= bit;
  }

  return (data);
}
//*****************************************************************************
//*****************************************************************************
// Function:   read_i2c_nvram
// Arguments:  UCHAR count     number of bytes to read
//             UCHAR *buf      area to store the bytes read
// Returns:    0 - failed
//             1 - success
//*****************************************************************************
//*****************************************************************************
unsigned long cpqfcTS_ReadNVRAM( void* GPIOin, void* GPIOout , USHORT count,
	UCHAR *buf )
{
  unsigned short i;

  if( !( tl_i2c_tx_start(GPIOin, GPIOout) ))
    return FALSE;

  // Select the NVRAM for "dummy" write, to set the address
  tl_i2c_tx_byte( GPIOout , SLAVE_WRITE_ADDRESS );
  if ( !tl_i2c_rx_ack(GPIOin, GPIOout ) )
    return( FALSE );

  // Now send the address where we want to start reading  
  tl_i2c_tx_byte( GPIOout , 0 );
  if ( !tl_i2c_rx_ack(GPIOin, GPIOout ) )
    return( FALSE );

  // Send a repeated start condition and select the
  //  slave for reading now.
  if( tl_i2c_tx_start(GPIOin, GPIOout) )
    tl_i2c_tx_byte( GPIOout, SLAVE_READ_ADDRESS );

  if ( !tl_i2c_rx_ack(GPIOin, GPIOout) )
    return( FALSE );

  // this loop will now read out the data and store it
  //  in the buffer pointed to by buf
  for ( i=0; i<count; i++) 
  {
    *buf++ = tl_i2c_rx_byte(GPIOin, GPIOout);

    // Send ACK by holding data line low for 1 clock
    if ( i < (count-1) )
      tl_i2c_clock_pulse( 0x08, GPIOout );
    else {
	// Don't send ack for final byte
      tl_i2c_clock_pulse( SET_DATA_HI, GPIOout );
    }
  }

  tl_i2c_tx_stop(GPIOin, GPIOout);

  return( TRUE );
}

//****************************************************************
//
//
//
// routines to set and clear the data and clock bits
//
//
//
//****************************************************************

static void tl_set_clock(void* gpioreg)
{
  ULONG ret_val;

  ret_val = readl( gpioreg );
  ret_val &= 0xffffffFBL;  // clear GPIO2 (SCL)
  writel( ret_val, gpioreg);
}

static void tl_clr_clock(void* gpioreg)
{
  ULONG ret_val;

  ret_val = readl( gpioreg );
  ret_val |= SET_CLOCK_LO;
  writel( ret_val, gpioreg);
}

//*****************************************************************
//
//
// This routine will advance the clock by one period
//
//
//*****************************************************************
static void tl_i2c_clock_pulse( UCHAR value, void* GPIOout  )
{
  ULONG ret_val;

  // clear the clock bit
  tl_clr_clock( GPIOout );

  i2c_delay(0);


  // read the port to preserve non-I2C bits
  ret_val = readl( GPIOout );

  // clear the data & clock bits
  ret_val &= 0xFFFFFFf3;

  // write the value passed in...
  // data can only change while clock is LOW!
  ret_val |= value;           // the data
  ret_val |= SET_CLOCK_LO;    // the clock
  writel( ret_val, GPIOout );

  i2c_delay(0);


  //set clock bit
  tl_set_clock( GPIOout);
}




//*****************************************************************
//
//
// This routine returns the 64-bit WWN
//
//
//*****************************************************************
int cpqfcTS_GetNVRAM_data( UCHAR *wwnbuf, UCHAR *buf )
{
  ULONG len;
  ULONG sub_len;
  ULONG ptr_inc;
  ULONG i;
  ULONG j;
  UCHAR *data_ptr;
  UCHAR  z;
  UCHAR  name;
  UCHAR  sub_name;
  UCHAR  done;
  int iReturn=0;  // def. 0 offset is failure to find WWN field
  

	  
  data_ptr = (UCHAR *)buf;

  done = FALSE;
  i = 0;

  while ( (i < 128) && (!done) ) 
  {
    z = data_ptr[i];\
    if ( !(z & 0x80) )  
    {	
      len  = 1 + (z & 0x07);

      name = (z & 0x78) >> 3;
      if (name == 0x0F)
        done = TRUE;
    }
    else 
    {
      name = z & 0x7F;
      len  = 3 + data_ptr[i+1] + (data_ptr[i+2] << 8);
           
      switch (name) 
      {
      case 0x0D:
	//
	  j = i + 3;
	  //
	  if ( data_ptr[j] == 0x3b ) {
	    len = 6;
	    break;
	  }

	  while ( j<(i+len) ) {
	    sub_name = (data_ptr[j] & 0x3f);
	    sub_len  = data_ptr[j+1] + 
	               (data_ptr[j+2] << 8);
            ptr_inc  = sub_len + 3; 
	    switch (sub_name) 
	    {
	    case 0x3C:
              memcpy( wwnbuf, &data_ptr[j+3], 8);
              iReturn = j+3;
              break;
            default:
              break;
	    }
	    j += ptr_inc;
          }
	  break;
        default:
	  break;
      }  
    }  
  //
    i += len;
  }  // end while 
  return iReturn;
}





// define a short 5 micro sec delay, and longer (ms) delay

static void i2c_delay(ULONG mstime)
{
  ULONG i;
  
// NOTE: we only expect to use these delays when reading
// our adapter's NVRAM, which happens only during adapter reset.
// Delay technique from "Linux Device Drivers", A. Rubini 
// (1st Ed.) pg 137.

//  printk(" delay %lx  ", mstime);
  if( mstime ) // ms delay?
  {
    // delay technique
    for( i=0; i < mstime; i++)
      udelay(1000); // 1ms per loop
	
  }
  else  // 5 micro sec delay
  
    udelay( 5 ); // micro secs
  
//  printk("done\n");
}