/*
 * Copyright 2015 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 busions 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 <bskeggs@redhat.com>
 */
#define g94_i2c_aux(p) container_of((p), struct g94_i2c_aux, base)
#include "aux.h"

struct g94_i2c_aux {
        struct nvkm_i2c_aux base;
        int ch;
};

static void
g94_i2c_aux_fini(struct g94_i2c_aux *aux)
{
        struct nvkm_device *device = aux->base.pad->i2c->subdev.device;
        nvkm_mask(device, 0x00e4e4 + (aux->ch * 0x50), 0x00310000, 0x00000000);
}

static int
g94_i2c_aux_init(struct g94_i2c_aux *aux)
{
        struct nvkm_device *device = aux->base.pad->i2c->subdev.device;
        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 = nvkm_rd32(device, 0x00e4e4 + (aux->ch * 0x50));
                udelay(1);
                if (!timeout--) {
                        AUX_ERR(&aux->base, "begin idle timeout %08x", ctrl);
                        return -EBUSY;
                }
        } while (ctrl & 0x03010000);

        /* set some magic, and wait up to 1ms for it to appear */
        nvkm_mask(device, 0x00e4e4 + (aux->ch * 0x50), 0x00300000, ureq);
        timeout = 1000;
        do {
                ctrl = nvkm_rd32(device, 0x00e4e4 + (aux->ch * 0x50));
                udelay(1);
                if (!timeout--) {
                        AUX_ERR(&aux->base, "magic wait %08x", ctrl);
                        g94_i2c_aux_fini(aux);
                        return -EBUSY;
                }
        } while ((ctrl & 0x03000000) != urep);

        return 0;
}

int
g94_i2c_aux_xfer(struct nvkm_i2c_aux *obj, bool retry,
                 u8 type, u32 addr, u8 *data, u8 *size)
{
        struct g94_i2c_aux *aux = g94_i2c_aux(obj);
        struct nvkm_device *device = aux->base.pad->i2c->subdev.device;
        const u32 base = aux->ch * 0x50;
        u32 ctrl, stat, timeout, retries = 0;
        u32 xbuf[4] = {};
        int ret, i;

        AUX_TRACE(&aux->base, "%d: %08x %d", type, addr, *size);

        ret = g94_i2c_aux_init(aux);
        if (ret < 0)
                goto out;

        stat = nvkm_rd32(device, 0x00e4e8 + base);
        if (!(stat & 0x10000000)) {
                AUX_TRACE(&aux->base, "sink not detected");
                ret = -ENXIO;
                goto out;
        }

        if (!(type & 1)) {
                memcpy(xbuf, data, *size);
                for (i = 0; i < 16; i += 4) {
                        AUX_TRACE(&aux->base, "wr %08x", xbuf[i / 4]);
                        nvkm_wr32(device, 0x00e4c0 + base + i, xbuf[i / 4]);
                }
        }

        ctrl  = nvkm_rd32(device, 0x00e4e4 + base);
        ctrl &= ~0x0001f1ff;
        ctrl |= type << 12;
        ctrl |= (*size ? (*size - 1) : 0x00000100);
        nvkm_wr32(device, 0x00e4e0 + base, addr);

        /* (maybe) retry transaction a number of times on failure... */
        do {
                /* reset, and delay a while if this is a retry */
                nvkm_wr32(device, 0x00e4e4 + base, 0x80000000 | ctrl);
                nvkm_wr32(device, 0x00e4e4 + base, 0x00000000 | ctrl);
                if (retries)
                        udelay(400);

                /* transaction request, wait up to 1ms for it to complete */
                nvkm_wr32(device, 0x00e4e4 + base, 0x00010000 | ctrl);

                timeout = 1000;
                do {
                        ctrl = nvkm_rd32(device, 0x00e4e4 + base);
                        udelay(1);
                        if (!timeout--) {
                                AUX_ERR(&aux->base, "timeout %08x", ctrl);
                                ret = -EIO;
                                goto out;
                        }
                } while (ctrl & 0x00010000);
                ret = 0;

                /* read status, and check if transaction completed ok */
                stat = nvkm_mask(device, 0x00e4e8 + base, 0, 0);
                if ((stat & 0x000f0000) == 0x00080000 ||
                    (stat & 0x000f0000) == 0x00020000)
                        ret = 1;
                if ((stat & 0x00000100))
                        ret = -ETIMEDOUT;
                if ((stat & 0x00000e00))
                        ret = -EIO;

                AUX_TRACE(&aux->base, "%02d %08x %08x", retries, ctrl, stat);
        } while (ret && retry && retries++ < 32);

        if (type & 1) {
                for (i = 0; i < 16; i += 4) {
                        xbuf[i / 4] = nvkm_rd32(device, 0x00e4d0 + base + i);
                        AUX_TRACE(&aux->base, "rd %08x", xbuf[i / 4]);
                }
                memcpy(data, xbuf, *size);
                *size = stat & 0x0000001f;
        }

out:
        g94_i2c_aux_fini(aux);
        return ret < 0 ? ret : (stat & 0x000f0000) >> 16;
}

int
g94_i2c_aux_new_(const struct nvkm_i2c_aux_func *func,
                 struct nvkm_i2c_pad *pad, int index, u8 drive,
                 struct nvkm_i2c_aux **paux)
{
        struct g94_i2c_aux *aux;

        if (!(aux = kzalloc(sizeof(*aux), GFP_KERNEL)))
                return -ENOMEM;
        *paux = &aux->base;

        nvkm_i2c_aux_ctor(func, pad, index, &aux->base);
        aux->ch = drive;
        aux->base.intr = 1 << aux->ch;
        return 0;
}

static const struct nvkm_i2c_aux_func
g94_i2c_aux = {
        .xfer = g94_i2c_aux_xfer,
};

int
g94_i2c_aux_new(struct nvkm_i2c_pad *pad, int index, u8 drive,
                struct nvkm_i2c_aux **paux)
{
        return g94_i2c_aux_new_(&g94_i2c_aux, pad, index, drive, paux);
}