src/soc/amd/stoneyridge/smbus_spd.c

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #include <amdblocks/agesawrapper.h>
   4 #include <amdblocks/acpimmio.h>
   5 #include <console/console.h>
   6 #include <device/pci_def.h>
   7 #include <device/device.h>
   8 #include <device/smbus_host.h>
   9 #include <soc/southbridge.h>
  10 #include <amdblocks/dimm_spd.h>
  11
  12 /*
  13  * readspd - Read one or more SPD bytes from a DIMM.
  14  *           Start with offset zero and read sequentially.
  15  *           Optimization relies on autoincrement to avoid
  16  *           sending offset for every byte.
  17  *          Reads 128 bytes in 7-8 ms at 400 KHz.
  18  */
  19 static int readspd(uint8_t SmbusSlaveAddress, char *buffer, size_t count)
  20 {
  21         uint8_t dev_addr;
  22         size_t index;
  23         int error;
  24         char *pbuf = buffer;
  25
  26         printk(BIOS_SPEW, "-------------READING SPD-----------\n");
  27         printk(BIOS_SPEW, "SmbusSlave: 0x%08X, count: %zd\n",
  28                                         SmbusSlaveAddress, count);
  29
  30         /*
  31          * Convert received device address to the format accepted by
  32          * do_smbus_read_byte and do_smbus_recv_byte.
  33          */
  34         dev_addr = (SmbusSlaveAddress >> 1);
  35
  36         /* Read the first SPD byte */
  37         error = do_smbus_read_byte((uintptr_t)acpimmio_smbus, dev_addr, 0);
  38         if (error < 0) {
  39                 printk(BIOS_ERR, "-------------SPD READ ERROR-----------\n");
  40                 return error;
  41         }
  42         *pbuf = (char)error;
  43         pbuf++;
  44
  45         /* Read the remaining SPD bytes using do_smbus_recv_byte for speed */
  46         for (index = 1 ; index < count ; index++) {
  47                 error = do_smbus_recv_byte((uintptr_t)acpimmio_smbus, dev_addr);
  48                 if (error < 0) {
  49                         printk(BIOS_ERR, "-------------SPD READ ERROR-----------\n");
  50                         return error;
  51                 }
  52                 *pbuf = (char)error;
  53                 pbuf++;
  54         }
  55         printk(BIOS_SPEW, "\n");
  56         printk(BIOS_SPEW, "-------------FINISHED READING SPD-----------\n");
  57
  58         return 0;
  59 }
  60
  61 int sb_read_spd(uint8_t spdAddress, char *buf, size_t len)
  62 {
  63         return readspd(spdAddress, buf, len);
  64 }