/*
 * This file is part of the coreboot project.
 *
 * Copyright (C) 2011 Advanced Micro Devices, Inc.
 *
 * 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; version 2 of the License.
 *
 * 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */
 
#include "Porting.h"
#include "AGESA.h"
#include "amdlib.h"

AGESA_STATUS AmdMemoryReadSPD (UINT32 unused1, UINT32 unused2, AGESA_READ_SPD_PARAMS *info);
#define DIMENSION(array)(sizeof (array)/ sizeof (array [0]))

/*#pragma optimize ("", off) // for source level debug
*---------------------------------------------------------------------------
*
* SPD address table - porting required
*/

static const UINT8 spdAddressLookup [2] [2] [4] =  // socket, channel, dimm
   {
   // socket 0
      {
         {0xA0, 0xA2},  // channel 0 dimms
         {0x00, 0x00},  // channel 1 dimms
      },
   // socket 1
      {
         {0x00, 0x00},  // channel 0 dimms
         {0x00, 0x00},  // channel 1 dimms
      },
   };

/*-----------------------------------------------------------------------------
 *
 * readSmbusByteData - read a single SPD byte from any offset
 */

static int readSmbusByteData (int iobase, int address, char *buffer, int offset)
   {
   unsigned int status;
   UINT64 limit;

   address |= 1; // set read bit
   
   __outbyte (iobase + 0, 0xFF);                // clear error status
   __outbyte (iobase + 1, 0x1F);                // clear error status
   __outbyte (iobase + 3, offset);              // offset in eeprom
   __outbyte (iobase + 4, address);             // slave address and read bit
   __outbyte (iobase + 2, 0x48);                // read byte command

   // time limit to avoid hanging for unexpected error status (should never happen)
   limit = __rdtsc () + 2000000000 / 10;
   for (;;)
      {
      status = __inbyte (iobase);
      if (__rdtsc () > limit) break;
      if ((status & 2) == 0) continue;               // SMBusInterrupt not set, keep waiting
      if ((status & 1) == 1) continue;               // HostBusy set, keep waiting
      break;
      }

   buffer [0] = __inbyte (iobase + 5);
   if (status == 2) status = 0;                      // check for done with no errors
   return status;
   }

/*-----------------------------------------------------------------------------
 *
 * readSmbusByte - read a single SPD byte from the default offset
 *                 this function is faster function readSmbusByteData
 */

static int readSmbusByte (int iobase, int address, char *buffer)
   {
   unsigned int status;
   UINT64 limit;

   __outbyte (iobase + 0, 0xFF);                // clear error status
   __outbyte (iobase + 2, 0x44);                // read command

   // time limit to avoid hanging for unexpected error status
   limit = __rdtsc () + 2000000000 / 10;
   for (;;)
      {
      status = __inbyte (iobase);
      if (__rdtsc () > limit) break;
      if ((status & 2) == 0) continue;               // SMBusInterrupt not set, keep waiting
      if ((status & 1) == 1) continue;               // HostBusy set, keep waiting
      break;
      }

   buffer [0] = __inbyte (iobase + 5);
   if (status == 2) status = 0;                      // check for done with no errors
   return status;
   }

/*---------------------------------------------------------------------------
 *
 * readspd - Read one or more SPD bytes from a DIMM.
 *           Start with offset zero and read sequentially.
 *           Optimization relies on autoincrement to avoid 
 *           sending offset for every byte.
 *          Reads 128 bytes in 7-8 ms at 400 KHz.
 */

static int readspd (int iobase, int SmbusSlaveAddress, char *buffer, int count)
   {
   int index, error;

   /* read the first byte using offset zero */
   error = readSmbusByteData (iobase, SmbusSlaveAddress, buffer, 0);
   if (error) return error;

   /* read the remaining bytes using auto-increment for speed */
   for (index = 1; index < count; index++)
      {
      error = readSmbusByte (iobase, SmbusSlaveAddress, &buffer [index]);
      if (error) return error;
      }
   
   return 0;
   }

static void writePmReg (int reg, int data)
   {
   __outbyte (0xCD6, reg);
   __outbyte (0xCD7, data);
   }

static void setupFch (int ioBase)
   {
   writePmReg (0x2D, ioBase >> 8);
   writePmReg (0x2C, ioBase | 1);
   writePmReg (0x29, 0x80);
   writePmReg (0x28, 0x61);
   __outbyte (ioBase + 0x0E, 66000000 / 400000 / 4); // set SMBus clock to 400 KHz
   }

AGESA_STATUS AmdMemoryReadSPD (UINT32 unused1, UINT32 unused2, AGESA_READ_SPD_PARAMS *info)
   {
   int spdAddress, ioBase;

   if (info->SocketId     >= DIMENSION (spdAddressLookup      )) return AGESA_ERROR; 
   if (info->MemChannelId >= DIMENSION (spdAddressLookup[0]   )) return AGESA_ERROR; 
   if (info->DimmId       >= DIMENSION (spdAddressLookup[0][0])) return AGESA_ERROR;
   
   spdAddress = spdAddressLookup [info->SocketId] [info->MemChannelId] [info->DimmId]; 
   if (spdAddress == 0) return AGESA_ERROR;
   ioBase = 0xB00;
   setupFch (ioBase);
   return readspd (ioBase, spdAddress, (void *) info->Buffer, 128);
   }
