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smbus_amd8.c

/* SMB handling routines for AMD8111, by YRS 2003.04.
      Information on how to access SMBus is provided
      by "Alex van Kaam", MANY THANKS!!

      Common to AMD8111 and NVidia nForce2


      SMBus IO method:

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

      The following note does not apply to NVidia nForce2!
      Uses always the lowest bit 1, and read/write is distinguished
      by the control command number.

------------------------------------------------------------------------
      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 LOOP_COUNT      0x2000
#define LOOP_WAIT 0x20

/* command address */
#define SMBGLENB  0x0 /* SMBus global enable */
#define SMBGLSTS  0x1 /* SMBus global status */
#define SMBHADDR  0x2 /* host address register */
#define SMBHCMD     0x3 /* command register for host controller */
#define SMBHDATA0 0x4 /* data 0 register for host controller */
#define SMBHDATA1 0x5 /* data 1 register for host controller */

/* status flag */
#define SMBHSTS_OKOK    0x00  /* transaction successful */
#define SMBHSTS_NOACK   0x10  /* not acknowledged (no device) */
#define SMBHSTS_DEVERR  0x11  /* device error */
#define SMBHSTS_TIMEOUT 0x18  /* timeout */
#define SMBHSTS_PROTERR 0x19  /* protocol error */
#define SMBHSTS_BUSY    0x1A  /* device busy or arbitration lost */
#define SMBHSTS_PECERR  0x1F  /* PEC(Packet Error Checking) error */
#define SMBHSTS_ALLERR  0x1F  /* all bits of error above */
#define SMBHSTS_ALRM    0x40  /* alarm message received */
#define SMBHSTS_DONE    0x80  /* command completed */

/* control command number */
#define SMBHCTRL_BYTEW  0x06  /* write byte */
#define SMBHCTRL_BYTER  0x07  /* read byte */
#define SMBHCTRL_WORDW  0x08  /* write word */
#define SMBHCTRL_WORDR  0x09  /* read word */


static int readbyte(int smb_base, int addr, int cmd)
{
      u_char dat = 0, saddr = 2*(addr/2) + 1;
      int i;

top:
      OUTb((u_short) (smb_base + SMBHADDR), (u_char) saddr); WAIT; WAIT;
      OUTb((u_short) (smb_base + SMBHCMD), (u_char) cmd); WAIT; WAIT;
      OUTb((u_short) (smb_base + SMBGLENB), SMBHCTRL_BYTER); WAIT; WAIT;

      for (i = 0; i < LOOP_WAIT; ++i)
            WAIT;

      for (i = 0; i < LOOP_COUNT; ++i) {
            dat = INb((u_short) (smb_base + SMBGLSTS)); WAIT; WAIT;
#ifdef SMB_DEBUG
fprintf(stderr, "   Readbyte: flag = 0x%02X, loop#:%04d\n", dat, i);
#endif
            if (dat == SMBHSTS_BUSY || dat == SMBHSTS_TIMEOUT)
                  goto top;
            if (dat & (SMBHSTS_DONE | SMBHSTS_ALLERR))
                  break;
      }
#ifdef SMB_DEBUG
if(i != LOOP_COUNT)
fprintf(stderr,
"   fx:Readbyte: addr=0x%02X, cmd=0x%02X flag = 0x%02X, loop#:%04d\n",
addr, cmd, dat, i);
#endif
      if (dat == SMBHSTS_DONE) {
            dat = INb((u_short) (smb_base + SMBHDATA0)); WAIT; WAIT;
#ifdef SMB_DEBUG
fprintf(stderr, "   fy:Readbyte: addr=0x%02X, cmd=0x%02X, dat = 0x%02X\n",
                        addr, cmd, dat);
#endif
            return (dat & 0xFF);
      } else
            return -1;
}

static int readword(int smb_base, int addr, int cmd)
{
      u_char dat = 0, saddr = 2*(addr/2) + 1;
      int i;

top:
      OUTb((u_short) (smb_base + SMBHADDR), (u_char) saddr); WAIT; WAIT;
      OUTb((u_short) (smb_base + SMBHCMD), (u_char) cmd); WAIT; WAIT;
      OUTb((u_short) (smb_base + SMBGLENB), SMBHCTRL_WORDR); WAIT; WAIT;

      for (i = 0; i < LOOP_WAIT; ++i)
            WAIT;

      for (i = 0; i < LOOP_COUNT; ++i) {
            dat = INb((u_short) (smb_base + SMBGLSTS)); WAIT; WAIT;
            if (dat == SMBHSTS_BUSY || dat == SMBHSTS_TIMEOUT)
                  goto top;
            if (dat & (SMBHSTS_DONE | SMBHSTS_ALLERR))
                  break;
      }
#ifdef SMB_DEBUG
if(i != LOOP_COUNT)
fprintf(stderr,
"   fx:Readword: addr=0x%02X, cmd=0x%02X flag = 0x%02X, loop#:%04d\n",
addr, cmd, dat, i);
#endif
      if (dat == SMBHSTS_DONE) {
            i = INb((u_short) (smb_base + SMBHDATA1)); WAIT; WAIT;
            dat = INb((u_short) (smb_base + SMBHDATA0)); WAIT; WAIT;
#ifdef SMB_DEBUG
fprintf(stderr, "   fy:Readword: addr=0x%02X, cmd=0x%02X, dat = 0x%02X\n",
                        addr, cmd, dat);
#endif
            return (((i << 8) + dat) & 0xFFFF);
      } else
            return -1;
}

static int writebyte(int smb_base, int addr, int cmd, int value)
{
      u_char dat = 0, saddr = 2*(addr/2) + 1;
      int i;

top:
      OUTb((u_short) (smb_base + SMBHADDR), (u_char) 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 + SMBGLENB), SMBHCTRL_BYTEW); WAIT; WAIT;

      for (i = 0; i < LOOP_WAIT; ++i)
            WAIT;

      for (i = 0; i < LOOP_COUNT; ++i) {
            dat = INb((u_short) (smb_base + SMBGLSTS)); WAIT; WAIT;
#ifdef SMB_DEBUG
fprintf(stderr, "   Writebyte: flag = 0x%02X, loop#:%04d\n", dat, i);
#endif
            if (dat == SMBHSTS_BUSY || dat == SMBHSTS_TIMEOUT)
                  goto top;
            if (dat & (SMBHSTS_DONE | SMBHSTS_ALLERR))
                  break;
      }
#ifdef SMB_DEBUG
if(i != LOOP_COUNT)
fprintf(stderr,
"   fx:Writebyte: addr=0x%02X, cmd=0x%02X flag = 0x%02X, loop#:%04d\n",
addr, cmd, dat, i);
#endif
      if (dat == SMBHSTS_DONE)
            return 0;
      else
            return -1;
}

static int writeword(int smb_base, int addr, int cmd, int value)
{
      u_char dat = 0, saddr = 2*(addr/2) + 1;
      int i;

top:
      OUTb((u_short) (smb_base + SMBHADDR), (u_char) 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 + SMBGLENB), SMBHCTRL_WORDW); WAIT; WAIT;

      for (i = 0; i < LOOP_WAIT; ++i)
            WAIT;

      for (i = 0; i < LOOP_COUNT; ++i) {
            dat = INb((u_short) (smb_base + SMBGLSTS)); WAIT; WAIT;
            if (dat == SMBHSTS_BUSY || dat == SMBHSTS_TIMEOUT)
                  goto top;
            if (dat & (SMBHSTS_DONE | SMBHSTS_ALLERR))
                  break;
      }
#ifdef SMB_DEBUG
if(i != LOOP_COUNT)
fprintf(stderr,
"   fx:Writeword: addr=0x%02X, cmd=0x%02X flag = 0x%02X, loop#:%04d\n",
addr, cmd, dat, i);
#endif
      if (dat == SMBHSTS_DONE)
            return 0;
      else
            return -1;
}

struct smbus_io smbus_amd8 = {
      readbyte, readword, writebyte, writeword
};

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