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smbus_ali.c

/* SMB handling routines for ALi 1535D+, by YRS 2002.07.
      Information on how to access SMBus is provided
      by ":p araffin.(Yoneya)", MANY THANKS!!


      SMBus IO method:

      smb_base  : Base Address
      addr      : Slave Device Address
      cmd       : Command Register 

      Note that SMBus Slave Device Address is totall 1byte data,
      whose upper 7bits is for address and the lowest bit for read (=1)
      and for write (=0).
      The input "addr" in the following routines is this 1byte data,
      where the lowest bit can be either 0 or 1.

            7             0
           +-+-+-+-+-+-+-+-+
           | Slave addr. |f|    f = 0 for write, =1 for read.
           +-+-+-+-+-+-+-+-+

      Do not confuse "Slave address" which is "addr(here)"/2!

 */

#ifdef SMB_DEBUG
extern int debug_flag;
#include <stdio.h>
#endif

#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>

#include "smbuses.h"
#include "io_cpu.h"

#define LSB       0x01

#define LOOP_COUNT      0x2000

/* command address */
#define SMBHSTS   0x0 /* SMBus host/slave status register */
#define SMBHCTRL  0x1 /* SMBus host/slave control register */
#define SMBSTART  0x2 /* start to generate programmed cycle */
#define SMBHADDR  0x3 /* host address register */
#define SMBHDATA0 0x4 /* data A register for host controller */
#define SMBHDATA1 0x5 /* data B register for host controller */
#define SMBHCMD     0x7 /* command register for host controller */

/* status flag */
#define SMBHSTS_WRONG   0x00  /* something wrong, restart */
#define SMBHSTS_IDLE    0x04  /* host idle, can put commands */
#define SMBHSTS_BUSY    0x08  /* host busy */
#define SMBHSTS_DONE    0x10  /* command completed */
#define SMBHSTS_DEVERR  0x20  /* device error */
#define SMBHSTS_BUSERR  0x40  /* bus collision or no response */
#define SMBHSTS_FAILED  0x80  /* failed bus transaction */
#define SMBHSTS_ALLERR  0xE0  /* all the bad error bits */
#define SMBHSTS_CLEAR   0xFF  /* clear status */

/* control command number */
#define SMBHCTRL_HRESET 0x04  /* host reset */
#define SMBHCTRL_BRESET 0x08  /* entire bus reset */
#define SMBHCTRL_RESET  0x0C  /* reset */
#define SMBHCTRL_BYTE   0x20  /* write/read byte */
#define SMBHCTRL_WORD   0x30  /* write/read word */


static int readbyte(int smb_base, int addr, int cmd)
{
      u_char dat, saddr = 2*(addr/2);
      int i;

top:
      for (i = 0; i < LOOP_COUNT; ++i) {
            OUTb((u_short) smb_base, SMBHSTS_CLEAR); WAIT; WAIT;
            dat = INb((u_short) smb_base); WAIT; WAIT;
            if (dat & SMBHSTS_IDLE)
                  goto step;
      }
      OUTb((u_short) (smb_base + SMBHCTRL), SMBHCTRL_RESET); WAIT; WAIT;

step:
      OUTb((u_short) (smb_base + SMBHADDR), (saddr | LSB)); WAIT; WAIT;
      OUTb((u_short) (smb_base + SMBHCMD), (u_char) cmd); WAIT; WAIT;
      OUTb((u_short) (smb_base + SMBHCTRL), SMBHCTRL_BYTE); WAIT; WAIT;
      OUTb((u_short) (smb_base + SMBSTART), 0xFF); WAIT; WAIT;

      for (i = 0; i < LOOP_COUNT; ++i) {
            dat = INb((u_short) smb_base); WAIT; WAIT;
            if (!(dat & SMBHSTS_BUSY))
                  break;
      }
#ifdef SMB_DEBUG
if (debug_flag > 1)
fprintf(stderr, "   Readbyte: flag = 0x%02X, loop#:%04d", dat, i);
#endif
      if (dat == SMBHSTS_WRONG) {
            OUTb((u_short) (smb_base + SMBHCTRL), SMBHCTRL_RESET); WAIT; WAIT;
#ifdef SMB_DEBUG
if (debug_flag > 1)
fprintf(stderr, "\n   OH!  wrong   ! = 0x%02X\n", dat);
#endif
            goto top;   
      } else if (dat & SMBHSTS_DONE) {
            dat = INb((u_short) (smb_base + SMBHDATA0)); WAIT; WAIT;
            return (dat & 0xFF);
      } else
            return -1;
}

static int readword(int smb_base, int addr, int cmd)
{
      u_char dat, saddr = 2*(addr/2);
      int i;

top:
      for (i = 0; i < LOOP_COUNT; ++i) {
            OUTb((u_short) smb_base, SMBHSTS_CLEAR); WAIT; WAIT;
            dat = INb((u_short) smb_base); WAIT; WAIT;
            if (dat & SMBHSTS_IDLE)
                  goto step;
      }
      OUTb((u_short) (smb_base + SMBHCTRL), SMBHCTRL_RESET); WAIT; WAIT;

step:
      OUTb((u_short) (smb_base + SMBHADDR), (saddr | LSB)); WAIT; WAIT;
      OUTb((u_short) (smb_base + SMBHCMD), (u_char) cmd); WAIT; WAIT;
      OUTb((u_short) (smb_base + SMBHCTRL), SMBHCTRL_WORD); WAIT; WAIT;
      OUTb((u_short) (smb_base + SMBSTART), 0xFF); WAIT; WAIT;

      for (i = 0; i < LOOP_COUNT; ++i) {
            dat = INb((u_short) smb_base); WAIT; WAIT;
            if (!(dat & SMBHSTS_BUSY))
                  break;
      }
      if (dat == SMBHSTS_WRONG) {
            OUTb((u_short) (smb_base + SMBHCTRL), SMBHCTRL_RESET); WAIT; WAIT;
            goto top;   
      } else if (dat & SMBHSTS_DONE) {
            i = INb((u_short) (smb_base + SMBHDATA1)); WAIT; WAIT;
            dat = INb((u_short) (smb_base + SMBHDATA0)); WAIT; WAIT;
            return (((i << 8) + dat) & 0xFFFF);
      } else
            return -1;
}

static int writebyte(int smb_base, int addr, int cmd, int value)
{
      u_char dat, saddr = 2*(addr/2);
      int i;

      for (i = 0; i < LOOP_COUNT; ++i) {
            OUTb((u_short) smb_base, SMBHSTS_CLEAR); WAIT; WAIT;
            dat = INb((u_short) smb_base); WAIT; WAIT;
            if (dat & SMBHSTS_IDLE)
                  goto step;
      }
      OUTb((u_short) (smb_base + SMBHCTRL), SMBHCTRL_RESET); WAIT; WAIT;

step:
      OUTb((u_short) (smb_base + SMBHADDR), saddr); WAIT; WAIT;
      OUTb((u_short) (smb_base + SMBHCMD), (u_char) cmd); WAIT; WAIT;
      OUTb((u_short) (smb_base + SMBHDATA0), (u_char) value); WAIT; WAIT;
      OUTb((u_short) (smb_base + SMBHCTRL), SMBHCTRL_BYTE); WAIT; WAIT;
      OUTb((u_short) (smb_base + SMBSTART), 0xFF); WAIT; WAIT;

      for (i = 0; i < LOOP_COUNT; ++i) {
            dat = INb((u_short) smb_base); WAIT; WAIT;
            if (!(dat & SMBHSTS_BUSY))
                  break;
      }
      if (dat & SMBHSTS_DONE)
            return 0;
      else
            return -1;
}

static int writeword(int smb_base, int addr, int cmd, int value)
{
      u_char dat, saddr = 2*(addr/2);
      int i;

      for (i = 0; i < LOOP_COUNT; ++i) {
            OUTb((u_short) smb_base, SMBHSTS_CLEAR); WAIT; WAIT;
            dat = INb((u_short) smb_base); WAIT; WAIT;
            if (dat & SMBHSTS_IDLE)
                  goto step;
      }
      OUTb((u_short) (smb_base + SMBHCTRL), SMBHCTRL_RESET); WAIT; WAIT;

step:
      OUTb((u_short) (smb_base + SMBHADDR), saddr); WAIT; WAIT;
      OUTb((u_short) (smb_base + SMBHCMD), (u_char) cmd); WAIT; WAIT;
      OUTb((u_short) (smb_base + SMBHDATA0), (u_char) (value & 0xFF)); WAIT; WAIT;
      OUTb((u_short) (smb_base + SMBHDATA1), (u_char) (value >> 8)); WAIT; WAIT;
      OUTb((u_short) (smb_base + SMBHCTRL), SMBHCTRL_WORD); WAIT; WAIT;
      OUTb((u_short) (smb_base + SMBSTART), 0xFF); WAIT; WAIT;

      for (i = 0; i < LOOP_COUNT; ++i) {
            dat = INb((u_short) smb_base); WAIT; WAIT;
            if (!(dat & SMBHSTS_BUSY))
                  break;
      }
      if (dat & SMBHSTS_DONE)
            return 0;
      else
            return -1;
}

struct smbus_io smbus_ali = {
      readbyte, readword, writebyte, writeword
};

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