aux.c

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/*
 * Copyright 2009 Red Hat Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * Authors: Ben Skeggs
 */

#include <subdev/i2c.h>

/******************************************************************************
 * aux channel util functions
 *****************************************************************************/
#define AUX_DBG(fmt, args...) nv_debug(aux, "AUXCH(%d): " fmt, ch, ##args)
#define AUX_ERR(fmt, args...) nv_error(aux, "AUXCH(%d): " fmt, ch, ##args)

static void
auxch_fini(struct nouveau_i2c *aux, int ch)
{
    nv_mask(aux, 0x00e4e4 + (ch * 0x50), 0x00310000, 0x00000000);
}

static int
auxch_init(struct nouveau_i2c *aux, int ch)
{
    const u32 unksel = 1; /* nfi which to use, or if it matters.. */
    const u32 ureq = unksel ? 0x00100000 : 0x00200000;
    const u32 urep = unksel ? 0x01000000 : 0x02000000;
    u32 ctrl, timeout;

    /* wait up to 1ms for any previous transaction to be done... */
    timeout = 1000;
    do {
        ctrl = nv_rd32(aux, 0x00e4e4 + (ch * 0x50));
        udelay(1);
        if (!timeout--) {
            AUX_ERR("begin idle timeout 0x%08x", ctrl);
            return -EBUSY;
        }
    } while (ctrl & 0x03010000);

    /* set some magic, and wait up to 1ms for it to appear */
    nv_mask(aux, 0x00e4e4 + (ch * 0x50), 0x00300000, ureq);
    timeout = 1000;
    do {
        ctrl = nv_rd32(aux, 0x00e4e4 + (ch * 0x50));
        udelay(1);
        if (!timeout--) {
            AUX_ERR("magic wait 0x%08x\n", ctrl);
            auxch_fini(aux, ch);
            return -EBUSY;
        }
    } while ((ctrl & 0x03000000) != urep);

    return 0;
}

static int
auxch_tx(struct nouveau_i2c *aux, int ch, u8 type, u32 addr, u8 *data, u8 size)
{
    u32 ctrl, stat, timeout, retries;
    u32 xbuf[4] = {};
    int ret, i;

    AUX_DBG("%d: 0x%08x %d\n", type, addr, size);

    ret = auxch_init(aux, ch);
    if (ret)
        goto out;

    stat = nv_rd32(aux, 0x00e4e8 + (ch * 0x50));
    if (!(stat & 0x10000000)) {
        AUX_DBG("sink not detected\n");
        ret = -ENXIO;
        goto out;
    }

    if (!(type & 1)) {
        memcpy(xbuf, data, size);
        for (i = 0; i < 16; i += 4) {
            AUX_DBG("wr 0x%08x\n", xbuf[i / 4]);
            nv_wr32(aux, 0x00e4c0 + (ch * 0x50) + i, xbuf[i / 4]);
        }
    }

    ctrl  = nv_rd32(aux, 0x00e4e4 + (ch * 0x50));
    ctrl &= ~0x0001f0ff;
    ctrl |= type << 12;
    ctrl |= size - 1;
    nv_wr32(aux, 0x00e4e0 + (ch * 0x50), addr);

    /* retry transaction a number of times on failure... */
    ret = -EREMOTEIO;
    for (retries = 0; retries < 32; retries++) {
        /* reset, and delay a while if this is a retry */
        nv_wr32(aux, 0x00e4e4 + (ch * 0x50), 0x80000000 | ctrl);
        nv_wr32(aux, 0x00e4e4 + (ch * 0x50), 0x00000000 | ctrl);
        if (retries)
            udelay(400);

        /* transaction request, wait up to 1ms for it to complete */
        nv_wr32(aux, 0x00e4e4 + (ch * 0x50), 0x00010000 | ctrl);

        timeout = 1000;
        do {
            ctrl = nv_rd32(aux, 0x00e4e4 + (ch * 0x50));
            udelay(1);
            if (!timeout--) {
                AUX_ERR("tx req timeout 0x%08x\n", ctrl);
                goto out;
            }
        } while (ctrl & 0x00010000);

        /* read status, and check if transaction completed ok */
        stat = nv_mask(aux, 0x00e4e8 + (ch * 0x50), 0, 0);
        if (!(stat & 0x000f0f00)) {
            ret = 0;
            break;
        }

        AUX_DBG("%02d 0x%08x 0x%08x\n", retries, ctrl, stat);
    }

    if (type & 1) {
        for (i = 0; i < 16; i += 4) {
            xbuf[i / 4] = nv_rd32(aux, 0x00e4d0 + (ch * 0x50) + i);
            AUX_DBG("rd 0x%08x\n", xbuf[i / 4]);
        }
        memcpy(data, xbuf, size);
    }

out:
    auxch_fini(aux, ch);
    return ret;
}

int
nv_rdaux(struct nouveau_i2c_port *auxch, u32 addr, u8 *data, u8 size)
{
    return auxch_tx(auxch->i2c, auxch->drive, 9, addr, data, size);
}

int
nv_wraux(struct nouveau_i2c_port *auxch, u32 addr, u8 *data, u8 size)
{
    return auxch_tx(auxch->i2c, auxch->drive, 8, addr, data, size);
}

static int
aux_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
    struct nouveau_i2c_port *auxch = (struct nouveau_i2c_port *)adap;
    struct i2c_msg *msg = msgs;
    int ret, mcnt = num;

    while (mcnt--) {
        u8 remaining = msg->len;
        u8 *ptr = msg->buf;

        while (remaining) {
            u8 cnt = (remaining > 16) ? 16 : remaining;
            u8 cmd;

            if (msg->flags & I2C_M_RD)
                cmd = 1;
            else
                cmd = 0;

            if (mcnt || remaining > 16)
                cmd |= 4; /* MOT */

            ret = auxch_tx(auxch->i2c, auxch->drive, cmd,
                       msg->addr, ptr, cnt);
            if (ret < 0)
                return ret;

            ptr += cnt;
            remaining -= cnt;
        }

        msg++;
    }

    return num;
}

static u32
aux_func(struct i2c_adapter *adap)
{
    return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}

const struct i2c_algorithm nouveau_i2c_aux_algo = {
    .master_xfer = aux_xfer,
    .functionality = aux_func
};