/*
 * Copyright (c) 2017, NVIDIA CORPORATION. All rights reserved.
 *
 * 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.
 *
 */
#include "qmgr.h"

static bool
nvkm_falcon_cmdq_has_room(struct nvkm_falcon_cmdq *cmdq, u32 size, bool *rewind)
{
        u32 head = nvkm_falcon_rd32(cmdq->qmgr->falcon, cmdq->head_reg);
        u32 tail = nvkm_falcon_rd32(cmdq->qmgr->falcon, cmdq->tail_reg);
        u32 free;

        size = ALIGN(size, QUEUE_ALIGNMENT);

        if (head >= tail) {
                free = cmdq->offset + cmdq->size - head;
                free -= HDR_SIZE;

                if (size > free) {
                        *rewind = true;
                        head = cmdq->offset;
                }
        }

        if (head < tail)
                free = tail - head - 1;

        return size <= free;
}

static void
nvkm_falcon_cmdq_push(struct nvkm_falcon_cmdq *cmdq, void *data, u32 size)
{
        struct nvkm_falcon *falcon = cmdq->qmgr->falcon;
        nvkm_falcon_pio_wr(falcon, data, 0, 0, DMEM, cmdq->position, size, 0, false);
        cmdq->position += ALIGN(size, QUEUE_ALIGNMENT);
}

static void
nvkm_falcon_cmdq_rewind(struct nvkm_falcon_cmdq *cmdq)
{
        struct nvfw_falcon_cmd cmd;

        cmd.unit_id = NV_FALCON_CMD_UNIT_ID_REWIND;
        cmd.size = sizeof(cmd);
        nvkm_falcon_cmdq_push(cmdq, &cmd, cmd.size);

        cmdq->position = cmdq->offset;
}

static int
nvkm_falcon_cmdq_open(struct nvkm_falcon_cmdq *cmdq, u32 size)
{
        struct nvkm_falcon *falcon = cmdq->qmgr->falcon;
        bool rewind = false;

        mutex_lock(&cmdq->mutex);

        if (!nvkm_falcon_cmdq_has_room(cmdq, size, &rewind)) {
                FLCNQ_DBG(cmdq, "queue full");
                mutex_unlock(&cmdq->mutex);
                return -EAGAIN;
        }

        cmdq->position = nvkm_falcon_rd32(falcon, cmdq->head_reg);

        if (rewind)
                nvkm_falcon_cmdq_rewind(cmdq);

        return 0;
}

static void
nvkm_falcon_cmdq_close(struct nvkm_falcon_cmdq *cmdq)
{
        nvkm_falcon_wr32(cmdq->qmgr->falcon, cmdq->head_reg, cmdq->position);
        mutex_unlock(&cmdq->mutex);
}

static int
nvkm_falcon_cmdq_write(struct nvkm_falcon_cmdq *cmdq, struct nvfw_falcon_cmd *cmd)
{
        static unsigned timeout = 2000;
        unsigned long end_jiffies = jiffies + msecs_to_jiffies(timeout);
        int ret = -EAGAIN;

        while (ret == -EAGAIN && time_before(jiffies, end_jiffies))
                ret = nvkm_falcon_cmdq_open(cmdq, cmd->size);
        if (ret) {
                FLCNQ_ERR(cmdq, "timeout waiting for queue space");
                return ret;
        }

        nvkm_falcon_cmdq_push(cmdq, cmd, cmd->size);
        nvkm_falcon_cmdq_close(cmdq);
        return ret;
}

/* specifies that we want to know the command status in the answer message */
#define CMD_FLAGS_STATUS BIT(0)
/* specifies that we want an interrupt when the answer message is queued */
#define CMD_FLAGS_INTR BIT(1)

int
nvkm_falcon_cmdq_send(struct nvkm_falcon_cmdq *cmdq, struct nvfw_falcon_cmd *cmd,
                      nvkm_falcon_qmgr_callback cb, void *priv,
                      unsigned long timeout)
{
        struct nvkm_falcon_qmgr_seq *seq;
        int ret;

        if (!wait_for_completion_timeout(&cmdq->ready,
                                         msecs_to_jiffies(1000))) {
                FLCNQ_ERR(cmdq, "timeout waiting for queue ready");
                return -ETIMEDOUT;
        }

        seq = nvkm_falcon_qmgr_seq_acquire(cmdq->qmgr);
        if (IS_ERR(seq))
                return PTR_ERR(seq);

        cmd->seq_id = seq->id;
        cmd->ctrl_flags = CMD_FLAGS_STATUS | CMD_FLAGS_INTR;

        seq->state = SEQ_STATE_USED;
        seq->async = !timeout;
        seq->callback = cb;
        seq->priv = priv;

        ret = nvkm_falcon_cmdq_write(cmdq, cmd);
        if (ret) {
                seq->state = SEQ_STATE_PENDING;
                nvkm_falcon_qmgr_seq_release(cmdq->qmgr, seq);
                return ret;
        }

        if (!seq->async) {
                if (!wait_for_completion_timeout(&seq->done, timeout)) {
                        FLCNQ_ERR(cmdq, "timeout waiting for reply");
                        return -ETIMEDOUT;
                }
                ret = seq->result;
                nvkm_falcon_qmgr_seq_release(cmdq->qmgr, seq);
        }

        return ret;
}

void
nvkm_falcon_cmdq_fini(struct nvkm_falcon_cmdq *cmdq)
{
        reinit_completion(&cmdq->ready);
}

void
nvkm_falcon_cmdq_init(struct nvkm_falcon_cmdq *cmdq,
                      u32 index, u32 offset, u32 size)
{
        const struct nvkm_falcon_func *func = cmdq->qmgr->falcon->func;

        cmdq->head_reg = func->cmdq.head + index * func->cmdq.stride;
        cmdq->tail_reg = func->cmdq.tail + index * func->cmdq.stride;
        cmdq->offset = offset;
        cmdq->size = size;
        complete_all(&cmdq->ready);

        FLCNQ_DBG(cmdq, "initialised @ index %d offset 0x%08x size 0x%08x",
                  index, cmdq->offset, cmdq->size);
}

void
nvkm_falcon_cmdq_del(struct nvkm_falcon_cmdq **pcmdq)
{
        struct nvkm_falcon_cmdq *cmdq = *pcmdq;
        if (cmdq) {
                kfree(*pcmdq);
                *pcmdq = NULL;
        }
}

int
nvkm_falcon_cmdq_new(struct nvkm_falcon_qmgr *qmgr, const char *name,
                     struct nvkm_falcon_cmdq **pcmdq)
{
        struct nvkm_falcon_cmdq *cmdq = *pcmdq;

        if (!(cmdq = *pcmdq = kzalloc_obj(*cmdq)))
                return -ENOMEM;

        cmdq->qmgr = qmgr;
        cmdq->name = name;
        mutex_init(&cmdq->mutex);
        init_completion(&cmdq->ready);
        return 0;
}