/*      $NetBSD: amdpm_smbus.c,v 1.26 2025/09/15 13:23:03 thorpej Exp $ */

/*
 * Copyright (c) 2005 Anil Gopinath (anil_public@yahoo.com)
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/* driver for SMBUS 1.0 host controller found in the
 * AMD-8111 HyperTransport I/O Hub
 */
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: amdpm_smbus.c,v 1.26 2025/09/15 13:23:03 thorpej Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/device.h>

#include <dev/pci/pcireg.h>
#include <dev/pci/pcivar.h>
#include <dev/pci/pcidevs.h>

#include <dev/i2c/i2cvar.h>
#include <dev/i2c/i2c_bitbang.h>

#include <dev/pci/amdpmreg.h>
#include <dev/pci/amdpmvar.h>

#include <dev/pci/amdpm_smbusreg.h>

static int       amdpm_smbus_exec(void *, i2c_op_t, i2c_addr_t, const void *,
                                  size_t, void *, size_t, int);
static int       amdpm_smbus_check_done(struct amdpm_softc *, i2c_op_t);
static void      amdpm_smbus_clear_gsr(struct amdpm_softc *);
static uint16_t amdpm_smbus_get_gsr(struct amdpm_softc *);
static int       amdpm_smbus_quick(struct amdpm_softc *, i2c_op_t);
static int       amdpm_smbus_send_1(struct amdpm_softc *, uint8_t, i2c_op_t);
static int       amdpm_smbus_write_1(struct amdpm_softc *, uint8_t,
                                     uint8_t, i2c_op_t);
static int       amdpm_smbus_receive_1(struct amdpm_softc *, i2c_op_t);
static int       amdpm_smbus_read_1(struct amdpm_softc *sc, uint8_t, i2c_op_t);

void
amdpm_smbus_attach(struct amdpm_softc *sc)
{

        /* register with iic */
        iic_tag_init(&sc->sc_i2c);
        sc->sc_i2c.ic_cookie = sc; 
        sc->sc_i2c.ic_exec = amdpm_smbus_exec;

        iicbus_attach(sc->sc_dev, &sc->sc_i2c);
}

static int
amdpm_smbus_exec(void *cookie, i2c_op_t op, i2c_addr_t addr, const void *cmd,
                 size_t cmdlen, void *vbuf, size_t buflen, int flags)
{
        struct amdpm_softc *sc  = (struct amdpm_softc *) cookie;
        sc->sc_smbus_slaveaddr  = addr;
        uint8_t *p = vbuf;
        int rv;
        
        if ((cmdlen == 0) && (buflen == 0))
                return amdpm_smbus_quick(sc, op);

        if (I2C_OP_READ_P(op) && (cmdlen == 0) && (buflen == 1)) {
                rv = amdpm_smbus_receive_1(sc, op);
                if (rv == -1)
                        return -1;
                *p = (uint8_t)rv;
                return 0;
        }
        
        if ((I2C_OP_READ_P(op)) && (cmdlen == 1) && (buflen == 1)) {
                rv = amdpm_smbus_read_1(sc, *(const uint8_t *)cmd, op);
                if (rv == -1)
                        return -1;
                *p = (uint8_t)rv;
                return 0;
        }
        
        if ((I2C_OP_WRITE_P(op)) && (cmdlen == 0) && (buflen == 1))
                return amdpm_smbus_send_1(sc, *(uint8_t*)vbuf, op);
        
        if ((I2C_OP_WRITE_P(op)) && (cmdlen == 1) && (buflen == 1))
                return amdpm_smbus_write_1(sc,
                                           *(const uint8_t*)cmd,
                                           *(uint8_t*)vbuf,
                                           op);
        
        return -1;  
}

static int 
amdpm_smbus_check_done(struct amdpm_softc *sc, i2c_op_t op)
{  
        int i;

        for (i = 0; i < 1000; i++) {
        /* check gsr and wait till cycle is done */
                uint16_t data = amdpm_smbus_get_gsr(sc);
                if (data & AMDPM_8111_GSR_CYCLE_DONE)
                        return 0;       
        }

        if (!(op & I2C_F_POLL))
            delay(1);

        return -1;    
}


static void
amdpm_smbus_clear_gsr(struct amdpm_softc *sc)
{
        /* clear register */
        uint16_t data = 0xFFFF;
        int off = (sc->sc_nforce ? 0xe0 : 0);
        bus_space_write_2(sc->sc_iot, sc->sc_ioh,
            AMDPM_8111_SMBUS_STAT - off, data);
}

static uint16_t
amdpm_smbus_get_gsr(struct amdpm_softc *sc)
{
        int off = (sc->sc_nforce ? 0xe0 : 0);
        return bus_space_read_2(sc->sc_iot, sc->sc_ioh,
            AMDPM_8111_SMBUS_STAT - off);
}

static int
amdpm_smbus_quick(struct amdpm_softc *sc, i2c_op_t op)
{
        uint16_t data = 0;
        int off = (sc->sc_nforce ? 0xe0 : 0);

        /* first clear gsr */
        amdpm_smbus_clear_gsr(sc);

        /* write smbus slave address and read/write bit to register */
        data = sc->sc_smbus_slaveaddr;
        data <<= 1;
        if (I2C_OP_READ_P(op))
                data |= AMDPM_8111_SMBUS_READ;

        bus_space_write_1(sc->sc_iot, sc->sc_ioh,
            AMDPM_8111_SMBUS_HOSTADDR - off, data);

        /* host start */
        bus_space_write_2(sc->sc_iot, sc->sc_ioh,
            AMDPM_8111_SMBUS_CTRL - off,
            AMDPM_8111_SMBUS_GSR_QUICK);        

        return amdpm_smbus_check_done(sc, op);
}

static int
amdpm_smbus_send_1(struct amdpm_softc *sc, uint8_t val, i2c_op_t op)
{
        uint16_t data = 0;
        int off = (sc->sc_nforce ? 0xe0 : 0);

        /* first clear gsr */
        amdpm_smbus_clear_gsr(sc);

        /* write smbus slave address to register */
        data = sc->sc_smbus_slaveaddr;
        data <<= 1;
        data |= AMDPM_8111_SMBUS_SEND;    
        bus_space_write_1(sc->sc_iot, sc->sc_ioh,
            AMDPM_8111_SMBUS_HOSTADDR - off, data);
        
        data = val;    
        /* store data */
        bus_space_write_2(sc->sc_iot, sc->sc_ioh,
            AMDPM_8111_SMBUS_HOSTDATA - off, data);
        /* host start */
        bus_space_write_2(sc->sc_iot, sc->sc_ioh,
            AMDPM_8111_SMBUS_CTRL - off,
            AMDPM_8111_SMBUS_GSR_SB);   

        return amdpm_smbus_check_done(sc, op);
}

  
static int
amdpm_smbus_write_1(struct amdpm_softc *sc, uint8_t cmd, uint8_t val,
                    i2c_op_t op)
{
        uint16_t data = 0;
        int off = (sc->sc_nforce ? 0xe0 : 0);

        /* first clear gsr */
        amdpm_smbus_clear_gsr(sc);  
  
        data = sc->sc_smbus_slaveaddr;
        data <<= 1;
        data |= AMDPM_8111_SMBUS_WRITE;    
        bus_space_write_1(sc->sc_iot, sc->sc_ioh,
            AMDPM_8111_SMBUS_HOSTADDR - off, data);
        
        data = val;    
        /* store cmd */
        bus_space_write_1(sc->sc_iot, sc->sc_ioh,
            AMDPM_8111_SMBUS_HOSTCMD - off, cmd);
        /* store data */    
        bus_space_write_2(sc->sc_iot, sc->sc_ioh,
            AMDPM_8111_SMBUS_HOSTDATA - off, data);    
        /* host start */
        bus_space_write_2(sc->sc_iot, sc->sc_ioh,
            AMDPM_8111_SMBUS_CTRL - off, AMDPM_8111_SMBUS_GSR_WB);
        
        return amdpm_smbus_check_done(sc, op);
}

static int
amdpm_smbus_receive_1(struct amdpm_softc *sc, i2c_op_t op)
{
        uint16_t data = 0;
        int off = (sc->sc_nforce ? 0xe0 : 0);

        /* first clear gsr */
        amdpm_smbus_clear_gsr(sc);  

        /* write smbus slave address to register */
        data = sc->sc_smbus_slaveaddr;
        data <<= 1;
        data |= AMDPM_8111_SMBUS_RX;    
        bus_space_write_1(sc->sc_iot, sc->sc_ioh,
            AMDPM_8111_SMBUS_HOSTADDR - off, data);
        
        /* start smbus cycle */
        bus_space_write_2(sc->sc_iot, sc->sc_ioh,
            AMDPM_8111_SMBUS_CTRL - off, AMDPM_8111_SMBUS_GSR_RXB);
        
        /* check for errors */
        if (amdpm_smbus_check_done(sc, op) < 0)
                return -1;
        
        /* read data */
        data = bus_space_read_2(sc->sc_iot, sc->sc_ioh,
            AMDPM_8111_SMBUS_HOSTDATA - off);
        uint8_t ret = (uint8_t)(data & 0x00FF);
        return ret;
}

static int
amdpm_smbus_read_1(struct amdpm_softc *sc, uint8_t cmd, i2c_op_t op)
{
        uint16_t data = 0;
        uint8_t ret;
        int off = (sc->sc_nforce ? 0xe0 : 0);

        /* first clear gsr */
        amdpm_smbus_clear_gsr(sc);  

        /* write smbus slave address to register */
        data = sc->sc_smbus_slaveaddr;
        data <<= 1;
        data |= AMDPM_8111_SMBUS_READ;    
        bus_space_write_1(sc->sc_iot, sc->sc_ioh,
            AMDPM_8111_SMBUS_HOSTADDR - off, data);
        
        /* store cmd */
        bus_space_write_1(sc->sc_iot, sc->sc_ioh,
            AMDPM_8111_SMBUS_HOSTCMD - off, cmd);
        /* host start */
        bus_space_write_2(sc->sc_iot, sc->sc_ioh,
            AMDPM_8111_SMBUS_CTRL - off, AMDPM_8111_SMBUS_GSR_RB);
        
        /* check for errors */
        if (amdpm_smbus_check_done(sc, op) < 0)
                return -1;
        
        /* store data */    
        data = bus_space_read_2(sc->sc_iot, sc->sc_ioh,
            AMDPM_8111_SMBUS_HOSTDATA - off);
        ret = (uint8_t)(data & 0x00FF);
        return ret;
}