/*
 * 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 "msgqueue.h"
#include <engine/falcon.h>

#include <subdev/secboot.h>


#define HDR_SIZE sizeof(struct nvkm_msgqueue_hdr)
#define QUEUE_ALIGNMENT 4
/* max size of the messages we can receive */
#define MSG_BUF_SIZE 128

static int
msg_queue_open(struct nvkm_msgqueue *priv, struct nvkm_msgqueue_queue *queue)
{
        struct nvkm_falcon *falcon = priv->falcon;

        mutex_lock(&queue->mutex);

        queue->position = nvkm_falcon_rd32(falcon, queue->tail_reg);

        return 0;
}

static void
msg_queue_close(struct nvkm_msgqueue *priv, struct nvkm_msgqueue_queue *queue,
                bool commit)
{
        struct nvkm_falcon *falcon = priv->falcon;

        if (commit)
                nvkm_falcon_wr32(falcon, queue->tail_reg, queue->position);

        mutex_unlock(&queue->mutex);
}

static bool
msg_queue_empty(struct nvkm_msgqueue *priv, struct nvkm_msgqueue_queue *queue)
{
        struct nvkm_falcon *falcon = priv->falcon;
        u32 head, tail;

        head = nvkm_falcon_rd32(falcon, queue->head_reg);
        tail = nvkm_falcon_rd32(falcon, queue->tail_reg);

        return head == tail;
}

static int
msg_queue_pop(struct nvkm_msgqueue *priv, struct nvkm_msgqueue_queue *queue,
              void *data, u32 size)
{
        struct nvkm_falcon *falcon = priv->falcon;
        const struct nvkm_subdev *subdev = priv->falcon->owner;
        u32 head, tail, available;

        head = nvkm_falcon_rd32(falcon, queue->head_reg);
        /* has the buffer looped? */
        if (head < queue->position)
                queue->position = queue->offset;

        tail = queue->position;

        available = head - tail;

        if (available == 0) {
                nvkm_warn(subdev, "no message data available\n");
                return 0;
        }

        if (size > available) {
                nvkm_warn(subdev, "message data smaller than read request\n");
                size = available;
        }

        nvkm_falcon_read_dmem(priv->falcon, tail, size, 0, data);
        queue->position += ALIGN(size, QUEUE_ALIGNMENT);

        return size;
}

static int
msg_queue_read(struct nvkm_msgqueue *priv, struct nvkm_msgqueue_queue *queue,
               struct nvkm_msgqueue_hdr *hdr)
{
        const struct nvkm_subdev *subdev = priv->falcon->owner;
        int err;

        err = msg_queue_open(priv, queue);
        if (err) {
                nvkm_error(subdev, "fail to open queue %d\n", queue->index);
                return err;
        }

        if (msg_queue_empty(priv, queue)) {
                err = 0;
                goto close;
        }

        err = msg_queue_pop(priv, queue, hdr, HDR_SIZE);
        if (err >= 0 && err != HDR_SIZE)
                err = -EINVAL;
        if (err < 0) {
                nvkm_error(subdev, "failed to read message header: %d\n", err);
                goto close;
        }

        if (hdr->size > MSG_BUF_SIZE) {
                nvkm_error(subdev, "message too big (%d bytes)\n", hdr->size);
                err = -ENOSPC;
                goto close;
        }

        if (hdr->size > HDR_SIZE) {
                u32 read_size = hdr->size - HDR_SIZE;

                err = msg_queue_pop(priv, queue, (hdr + 1), read_size);
                if (err >= 0 && err != read_size)
                        err = -EINVAL;
                if (err < 0) {
                        nvkm_error(subdev, "failed to read message: %d\n", err);
                        goto close;
                }
        }

close:
        msg_queue_close(priv, queue, (err >= 0));

        return err;
}

static bool
cmd_queue_has_room(struct nvkm_msgqueue *priv, struct nvkm_msgqueue_queue *queue,
                   u32 size, bool *rewind)
{
        struct nvkm_falcon *falcon = priv->falcon;
        u32 head, tail, free;

        size = ALIGN(size, QUEUE_ALIGNMENT);

        head = nvkm_falcon_rd32(falcon, queue->head_reg);
        tail = nvkm_falcon_rd32(falcon, queue->tail_reg);

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

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

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

        return size <= free;
}

static int
cmd_queue_push(struct nvkm_msgqueue *priv, struct nvkm_msgqueue_queue *queue,
               void *data, u32 size)
{
        nvkm_falcon_load_dmem(priv->falcon, data, queue->position, size, 0);
        queue->position += ALIGN(size, QUEUE_ALIGNMENT);

        return 0;
}

/* REWIND unit is always 0x00 */
#define MSGQUEUE_UNIT_REWIND 0x00

static void
cmd_queue_rewind(struct nvkm_msgqueue *priv, struct nvkm_msgqueue_queue *queue)
{
        const struct nvkm_subdev *subdev = priv->falcon->owner;
        struct nvkm_msgqueue_hdr cmd;
        int err;

        cmd.unit_id = MSGQUEUE_UNIT_REWIND;
        cmd.size = sizeof(cmd);
        err = cmd_queue_push(priv, queue, &cmd, cmd.size);
        if (err)
                nvkm_error(subdev, "queue %d rewind failed\n", queue->index);
        else
                nvkm_error(subdev, "queue %d rewinded\n", queue->index);

        queue->position = queue->offset;
}

static int
cmd_queue_open(struct nvkm_msgqueue *priv, struct nvkm_msgqueue_queue *queue,
               u32 size)
{
        struct nvkm_falcon *falcon = priv->falcon;
        const struct nvkm_subdev *subdev = priv->falcon->owner;
        bool rewind = false;

        mutex_lock(&queue->mutex);

        if (!cmd_queue_has_room(priv, queue, size, &rewind)) {
                nvkm_error(subdev, "queue full\n");
                mutex_unlock(&queue->mutex);
                return -EAGAIN;
        }

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

        if (rewind)
                cmd_queue_rewind(priv, queue);

        return 0;
}

static void
cmd_queue_close(struct nvkm_msgqueue *priv, struct nvkm_msgqueue_queue *queue,
                bool commit)
{
        struct nvkm_falcon *falcon = priv->falcon;

        if (commit)
                nvkm_falcon_wr32(falcon, queue->head_reg, queue->position);

        mutex_unlock(&queue->mutex);
}

static int
cmd_write(struct nvkm_msgqueue *priv, struct nvkm_msgqueue_hdr *cmd,
          struct nvkm_msgqueue_queue *queue)
{
        const struct nvkm_subdev *subdev = priv->falcon->owner;
        static unsigned timeout = 2000;
        unsigned long end_jiffies = jiffies + msecs_to_jiffies(timeout);
        int ret = -EAGAIN;
        bool commit = true;

        while (ret == -EAGAIN && time_before(jiffies, end_jiffies))
                ret = cmd_queue_open(priv, queue, cmd->size);
        if (ret) {
                nvkm_error(subdev, "pmu_queue_open_write failed\n");
                return ret;
        }

        ret = cmd_queue_push(priv, queue, cmd, cmd->size);
        if (ret) {
                nvkm_error(subdev, "pmu_queue_push failed\n");
                commit = false;
        }

           cmd_queue_close(priv, queue, commit);

        return ret;
}

static struct nvkm_msgqueue_seq *
msgqueue_seq_acquire(struct nvkm_msgqueue *priv)
{
        const struct nvkm_subdev *subdev = priv->falcon->owner;
        struct nvkm_msgqueue_seq *seq;
        u32 index;

        mutex_lock(&priv->seq_lock);

        index = find_first_zero_bit(priv->seq_tbl, NVKM_MSGQUEUE_NUM_SEQUENCES);

        if (index >= NVKM_MSGQUEUE_NUM_SEQUENCES) {
                nvkm_error(subdev, "no free sequence available\n");
                mutex_unlock(&priv->seq_lock);
                return ERR_PTR(-EAGAIN);
        }

        set_bit(index, priv->seq_tbl);

        mutex_unlock(&priv->seq_lock);

        seq = &priv->seq[index];
        seq->state = SEQ_STATE_PENDING;

        return seq;
}

static void
msgqueue_seq_release(struct nvkm_msgqueue *priv, struct nvkm_msgqueue_seq *seq)
{
        /* no need to acquire seq_lock since clear_bit is atomic */
        seq->state = SEQ_STATE_FREE;
        seq->callback = NULL;
        seq->completion = NULL;
        clear_bit(seq->id, priv->seq_tbl);
}

/* 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_msgqueue_post(struct nvkm_msgqueue *priv, enum msgqueue_msg_priority prio,
                   struct nvkm_msgqueue_hdr *cmd, nvkm_msgqueue_callback cb,
                   struct completion *completion, bool wait_init)
{
        struct nvkm_msgqueue_seq *seq;
        struct nvkm_msgqueue_queue *queue;
        int ret;

        if (wait_init && !wait_for_completion_timeout(&priv->init_done,
                                         msecs_to_jiffies(1000)))
                return -ETIMEDOUT;

        queue = priv->func->cmd_queue(priv, prio);
        if (IS_ERR(queue))
                return PTR_ERR(queue);

        seq = msgqueue_seq_acquire(priv);
        if (IS_ERR(seq))
                return PTR_ERR(seq);

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

        seq->callback = cb;
        seq->state = SEQ_STATE_USED;
        seq->completion = completion;

        ret = cmd_write(priv, cmd, queue);
        if (ret) {
                seq->state = SEQ_STATE_PENDING;
                      msgqueue_seq_release(priv, seq);
        }

        return ret;
}

static int
msgqueue_msg_handle(struct nvkm_msgqueue *priv, struct nvkm_msgqueue_hdr *hdr)
{
        const struct nvkm_subdev *subdev = priv->falcon->owner;
        struct nvkm_msgqueue_seq *seq;

        seq = &priv->seq[hdr->seq_id];
        if (seq->state != SEQ_STATE_USED && seq->state != SEQ_STATE_CANCELLED) {
                nvkm_error(subdev, "msg for unknown sequence %d", seq->id);
                return -EINVAL;
        }

        if (seq->state == SEQ_STATE_USED) {
                if (seq->callback)
                        seq->callback(priv, hdr);
        }

        if (seq->completion)
                complete(seq->completion);

           msgqueue_seq_release(priv, seq);

        return 0;
}

static int
msgqueue_handle_init_msg(struct nvkm_msgqueue *priv,
                         struct nvkm_msgqueue_hdr *hdr)
{
        struct nvkm_falcon *falcon = priv->falcon;
        const struct nvkm_subdev *subdev = falcon->owner;
        u32 tail;
        u32 tail_reg;
        int ret;

        /*
         * Of course the message queue registers vary depending on the falcon
         * used...
         */
        switch (falcon->owner->index) {
        case NVKM_SUBDEV_PMU:
                tail_reg = 0x4cc;
                break;
        case NVKM_ENGINE_SEC2:
                tail_reg = 0xa34;
                break;
        default:
                nvkm_error(subdev, "falcon %s unsupported for msgqueue!\n",
                           nvkm_subdev_name[falcon->owner->index]);
                return -EINVAL;
        }

        /*
         * Read the message - queues are not initialized yet so we cannot rely
         * on msg_queue_read()
         */
        tail = nvkm_falcon_rd32(falcon, tail_reg);
        nvkm_falcon_read_dmem(falcon, tail, HDR_SIZE, 0, hdr);

        if (hdr->size > MSG_BUF_SIZE) {
                nvkm_error(subdev, "message too big (%d bytes)\n", hdr->size);
                return -ENOSPC;
        }

        nvkm_falcon_read_dmem(falcon, tail + HDR_SIZE, hdr->size - HDR_SIZE, 0,
                              (hdr + 1));

        tail += ALIGN(hdr->size, QUEUE_ALIGNMENT);
        nvkm_falcon_wr32(falcon, tail_reg, tail);

        ret = priv->func->init_func->init_callback(priv, hdr);
        if (ret)
                return ret;

        return 0;
}

void
nvkm_msgqueue_process_msgs(struct nvkm_msgqueue *priv,
                           struct nvkm_msgqueue_queue *queue)
{
        /*
         * We are invoked from a worker thread, so normally we have plenty of
         * stack space to work with.
         */
        u8 msg_buffer[MSG_BUF_SIZE];
        struct nvkm_msgqueue_hdr *hdr = (void *)msg_buffer;
        int ret;

        /* the first message we receive must be the init message */
        if ((!priv->init_msg_received)) {
                ret = msgqueue_handle_init_msg(priv, hdr);
                if (!ret)
                        priv->init_msg_received = true;
        } else {
                while (msg_queue_read(priv, queue, hdr) > 0)
                        msgqueue_msg_handle(priv, hdr);
        }
}

void
nvkm_msgqueue_write_cmdline(struct nvkm_msgqueue *queue, void *buf)
{
        if (!queue || !queue->func || !queue->func->init_func)
                return;

        queue->func->init_func->gen_cmdline(queue, buf);
}

int
nvkm_msgqueue_acr_boot_falcons(struct nvkm_msgqueue *queue,
                               unsigned long falcon_mask)
{
        unsigned long falcon;

        if (!queue || !queue->func->acr_func)
                return -ENODEV;

        /* Does the firmware support booting multiple falcons? */
        if (queue->func->acr_func->boot_multiple_falcons)
                return queue->func->acr_func->boot_multiple_falcons(queue,
                                                                   falcon_mask);

        /* Else boot all requested falcons individually */
        if (!queue->func->acr_func->boot_falcon)
                return -ENODEV;

        for_each_set_bit(falcon, &falcon_mask, NVKM_SECBOOT_FALCON_END) {
                int ret = queue->func->acr_func->boot_falcon(queue, falcon);

                if (ret)
                        return ret;
        }

        return 0;
}

int
nvkm_msgqueue_new(u32 version, struct nvkm_falcon *falcon,
                  const struct nvkm_secboot *sb, struct nvkm_msgqueue **queue)
{
        const struct nvkm_subdev *subdev = falcon->owner;
        int ret = -EINVAL;

        switch (version) {
        case 0x0137c63d:
                ret = msgqueue_0137c63d_new(falcon, sb, queue);
                break;
        case 0x0137bca5:
                ret = msgqueue_0137bca5_new(falcon, sb, queue);
                break;
        case 0x0148cdec:
        case 0x015ccf3e:
                ret = msgqueue_0148cdec_new(falcon, sb, queue);
                break;
        default:
                nvkm_error(subdev, "unhandled firmware version 0x%08x\n",
                           version);
                break;
        }

        if (ret == 0) {
                nvkm_debug(subdev, "firmware version: 0x%08x\n", version);
                (*queue)->fw_version = version;
        }

        return ret;
}

void
nvkm_msgqueue_del(struct nvkm_msgqueue **queue)
{
        if (*queue) {
                (*queue)->func->dtor(*queue);
                *queue = NULL;
        }
}

void
nvkm_msgqueue_recv(struct nvkm_msgqueue *queue)
{
        if (!queue->func || !queue->func->recv) {
                const struct nvkm_subdev *subdev = queue->falcon->owner;

                nvkm_warn(subdev, "missing msgqueue recv function\n");
                return;
        }

        queue->func->recv(queue);
}

int
nvkm_msgqueue_reinit(struct nvkm_msgqueue *queue)
{
        /* firmware not set yet... */
        if (!queue)
                return 0;

        queue->init_msg_received = false;
        reinit_completion(&queue->init_done);

        return 0;
}

void
nvkm_msgqueue_ctor(const struct nvkm_msgqueue_func *func,
                   struct nvkm_falcon *falcon,
                   struct nvkm_msgqueue *queue)
{
        int i;

        queue->func = func;
        queue->falcon = falcon;
        mutex_init(&queue->seq_lock);
        for (i = 0; i < NVKM_MSGQUEUE_NUM_SEQUENCES; i++)
                queue->seq[i].id = i;

        init_completion(&queue->init_done);


}