i2c.c

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/*
 * Copyright 2012 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/bios.h"
#include "subdev/bios/dcb.h"
#include "subdev/bios/i2c.h"

u16
dcb_i2c_table(struct nouveau_bios *bios, u8 *ver, u8 *hdr, u8 *cnt, u8 *len)
{
    u16 i2c = 0x0000;
    u16 dcb = dcb_table(bios, ver, hdr, cnt, len);
    if (dcb) {
        if (*ver >= 0x15)
            i2c = nv_ro16(bios, dcb + 2);
        if (*ver >= 0x30)
            i2c = nv_ro16(bios, dcb + 4);
    }

    if (i2c && *ver >= 0x30) {
        *ver = nv_ro08(bios, i2c + 0);
        *hdr = nv_ro08(bios, i2c + 1);
        *cnt = nv_ro08(bios, i2c + 2);
        *len = nv_ro08(bios, i2c + 3);
    } else {
        *ver = *ver; /* use DCB version */
        *hdr = 0;
        *cnt = 16;
        *len = 4;
    }

    return i2c;
}

u16
dcb_i2c_entry(struct nouveau_bios *bios, u8 idx, u8 *ver, u8 *len)
{
    u8  hdr, cnt;
    u16 i2c = dcb_i2c_table(bios, ver, &hdr, &cnt, len);
    if (i2c && idx < cnt)
        return i2c + hdr + (idx * *len);
    return 0x0000;
}

int
dcb_i2c_parse(struct nouveau_bios *bios, u8 idx, struct dcb_i2c_entry *info)
{
    u8  ver, len;
    u16 ent = dcb_i2c_entry(bios, idx, &ver, &len);
    if (ent) {
        info->data = nv_ro32(bios, ent + 0);
        info->type = nv_ro08(bios, ent + 3);
        if (ver < 0x30) {
            info->type &= 0x07;
            if (info->type == 0x07)
                info->type = 0xff;
        }

        switch (info->type) {
        case DCB_I2C_NV04_BIT:
            info->drive = nv_ro08(bios, ent + 0);
            info->sense = nv_ro08(bios, ent + 1);
            return 0;
        case DCB_I2C_NV4E_BIT:
            info->drive = nv_ro08(bios, ent + 1);
            return 0;
        case DCB_I2C_NVIO_BIT:
        case DCB_I2C_NVIO_AUX:
            info->drive = nv_ro08(bios, ent + 0);
            return 0;
        case DCB_I2C_UNUSED:
            return 0;
        default:
            nv_warn(bios, "unknown i2c type %d\n", info->type);
            info->type = DCB_I2C_UNUSED;
            return 0;
        }
    }

    if (bios->bmp_offset && idx < 2) {
        /* BMP (from v4.0 has i2c info in the structure, it's in a
         * fixed location on earlier VBIOS
         */
        if (nv_ro08(bios, bios->bmp_offset + 5) < 4)
            ent = 0x0048;
        else
            ent = 0x0036 + bios->bmp_offset;

        if (idx == 0) {
            info->drive = nv_ro08(bios, ent + 4);
            if (!info->drive) info->drive = 0x3f;
            info->sense = nv_ro08(bios, ent + 5);
            if (!info->sense) info->sense = 0x3e;
        } else
        if (idx == 1) {
            info->drive = nv_ro08(bios, ent + 6);
            if (!info->drive) info->drive = 0x37;
            info->sense = nv_ro08(bios, ent + 7);
            if (!info->sense) info->sense = 0x36;
        }

        info->type = DCB_I2C_NV04_BIT;
        return 0;
    }

    return -ENOENT;
}