smbus_early_fch.c

Go to the documentation of this file.

/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <stdint.h>
#include <amdblocks/acpimmio.h>
#include <amdblocks/smbus.h>
#include <soc/iomap.h>
 
static void fch_smbus_enable_decode(uint16_t base)
{
        uint32_t val = pm_read32(PM_DECODE_EN);
        /* Configure upper byte of the I/O address; lower byte is always 0 */
        val = (val & ~SMBUS_ASF_IO_BASE_MASK) | (base & SMBUS_ASF_IO_BASE_MASK);
        /* Set enable decode bit even though it should already be set */
        val |= SMBUS_ASF_IO_EN;
        pm_write32(PM_DECODE_EN, val);
}
 
void fch_smbus_init(void)
{
        /* 400 kHz smbus speed. */
        const uint8_t smbus_speed = (66000000 / (400000 * 4));
 
        fch_smbus_enable_decode(SMB_BASE_ADDR);
        smbus_write8(SMBTIMING, smbus_speed);
        /* Clear all SMBUS status bits */
        smbus_write8(SMBHSTSTAT, SMBHST_STAT_CLEAR);
        smbus_write8(SMBSLVSTAT, SMBSLV_STAT_CLEAR);
        asf_write8(SMBHSTSTAT, SMBHST_STAT_CLEAR);
        asf_write8(SMBSLVSTAT, SMBSLV_STAT_CLEAR);
}