src/soc/amd/stoneyridge/smbus_spd.c

   1 /*
   2  * This file is part of the coreboot project.
   3  *
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; version 2 of the License.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 #include <amdblocks/agesawrapper.h>
  16 #include <console/console.h>
  17 #include <device/pci_def.h>
  18 #include <device/device.h>
  19 #include <device/smbus_host.h>
  20 #include <soc/southbridge.h>
  21 #include <amdblocks/dimm_spd.h>
  22
  23 /*
  24  * readspd - Read one or more SPD bytes from a DIMM.
  25  *           Start with offset zero and read sequentially.
  26  *           Optimization relies on autoincrement to avoid
  27  *           sending offset for every byte.
  28  *          Reads 128 bytes in 7-8 ms at 400 KHz.
  29  */
  30 static int readspd(uint8_t SmbusSlaveAddress, char *buffer, size_t count)
  31 {
  32         uint8_t dev_addr;
  33         size_t index;
  34         int error;
  35         char *pbuf = buffer;
  36
  37         printk(BIOS_SPEW, "-------------READING SPD-----------\n");
  38         printk(BIOS_SPEW, "SmbusSlave: 0x%08X, count: %zd\n",
  39                                         SmbusSlaveAddress, count);
  40
  41         /*
  42          * Convert received device address to the format accepted by
  43          * do_smbus_read_byte and do_smbus_recv_byte.
  44          */
  45         dev_addr = (SmbusSlaveAddress >> 1);
  46
  47         /* Read the first SPD byte */
  48         error = do_smbus_read_byte(ACPIMMIO_SMBUS_BASE, dev_addr, 0);
  49         if (error < 0) {
  50                 printk(BIOS_ERR, "-------------SPD READ ERROR-----------\n");
  51                 return error;
  52         }
  53         *pbuf = (char) error;
  54         pbuf++;
  55
  56         /* Read the remaining SPD bytes using do_smbus_recv_byte for speed */
  57         for (index = 1 ; index < count ; index++) {
  58                 error = do_smbus_recv_byte(ACPIMMIO_SMBUS_BASE, dev_addr);
  59                 if (error < 0) {
  60                         printk(BIOS_ERR, "-------------SPD READ ERROR-----------\n");
  61                         return error;
  62                 }
  63                 *pbuf = (char) error;
  64                 pbuf++;
  65         }
  66         printk(BIOS_SPEW, "\n");
  67         printk(BIOS_SPEW, "-------------FINISHED READING SPD-----------\n");
  68
  69         return 0;
  70 }
  71
  72 int sb_read_spd(uint8_t spdAddress, char *buf, size_t len)
  73 {
  74         return readspd(spdAddress, buf, len);
  75 }