smbus_spd.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <amdblocks/agesawrapper.h>
#include <amdblocks/acpimmio.h>
#include <console/console.h>
#include <device/pci_def.h>
#include <device/device.h>
#include <device/smbus_host.h>
#include <soc/southbridge.h>
#include <amdblocks/dimm_spd.h>
 
/*
 * 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(uint8_t SmbusSlaveAddress, char *buffer, size_t count)
{
        uint8_t dev_addr;
        size_t index;
        int error;
        char *pbuf = buffer;
 
        printk(BIOS_SPEW, "-------------READING SPD-----------\n");
        printk(BIOS_SPEW, "SmbusSlave: 0x%08X, count: %zd\n",
                                        SmbusSlaveAddress, count);
 
        /*
         * Convert received device address to the format accepted by
         * do_smbus_read_byte and do_smbus_recv_byte.
         */
        dev_addr = (SmbusSlaveAddress >> 1);
 
        /* Read the first SPD byte */
        error = do_smbus_read_byte((uintptr_t)acpimmio_smbus, dev_addr, 0);
        if (error < 0) {
                printk(BIOS_ERR, "-------------SPD READ ERROR-----------\n");
                return error;
        }
        *pbuf = (char) error;
        pbuf++;
 
        /* Read the remaining SPD bytes using do_smbus_recv_byte for speed */
        for (index = 1 ; index < count ; index++) {
                error = do_smbus_recv_byte((uintptr_t)acpimmio_smbus, dev_addr);
                if (error < 0) {
                        printk(BIOS_ERR, "-------------SPD READ ERROR-----------\n");
                        return error;
                }
                *pbuf = (char) error;
                pbuf++;
        }
        printk(BIOS_SPEW, "\n");
        printk(BIOS_SPEW, "-------------FINISHED READING SPD-----------\n");
 
        return 0;
}
 
int sb_read_spd(uint8_t spdAddress, char *buf, size_t len)
{
        return readspd(spdAddress, buf, len);
}