// SPDX-License-Identifier: GPL-2.0-only
/*
 * Tegra host1x Channel
 *
 * Copyright (c) 2010-2013, NVIDIA Corporation.
 */

#include <linux/slab.h>
#include <linux/module.h>

#include "channel.h"
#include "dev.h"
#include "job.h"

/* Constructor for the host1x device list */
int host1x_channel_list_init(struct host1x_channel_list *chlist,
                             unsigned int num_channels)
{
        chlist->channels = kzalloc_objs(struct host1x_channel, num_channels);
        if (!chlist->channels)
                return -ENOMEM;

        chlist->allocated_channels = bitmap_zalloc(num_channels, GFP_KERNEL);
        if (!chlist->allocated_channels) {
                kfree(chlist->channels);
                return -ENOMEM;
        }

        mutex_init(&chlist->lock);

        return 0;
}

void host1x_channel_list_free(struct host1x_channel_list *chlist)
{
        bitmap_free(chlist->allocated_channels);
        kfree(chlist->channels);
}

int host1x_job_submit(struct host1x_job *job)
{
        struct host1x *host = dev_get_drvdata(job->channel->dev->parent);

        return host1x_hw_channel_submit(host, job);
}
EXPORT_SYMBOL(host1x_job_submit);

struct host1x_channel *host1x_channel_get(struct host1x_channel *channel)
{
        kref_get(&channel->refcount);

        return channel;
}
EXPORT_SYMBOL(host1x_channel_get);

/**
 * host1x_channel_get_index() - Attempt to get channel reference by index
 * @host: Host1x device object
 * @index: Index of channel
 *
 * If channel number @index is currently allocated, increase its refcount
 * and return a pointer to it. Otherwise, return NULL.
 */
struct host1x_channel *host1x_channel_get_index(struct host1x *host,
                                                unsigned int index)
{
        struct host1x_channel *ch = &host->channel_list.channels[index];

        if (!kref_get_unless_zero(&ch->refcount))
                return NULL;

        return ch;
}

void host1x_channel_stop(struct host1x_channel *channel)
{
        struct host1x *host = dev_get_drvdata(channel->dev->parent);

        host1x_hw_cdma_stop(host, &channel->cdma);
}
EXPORT_SYMBOL(host1x_channel_stop);

/**
 * host1x_channel_stop_all() - disable CDMA on allocated channels
 * @host: host1x instance
 *
 * Stop CDMA on allocated channels
 */
void host1x_channel_stop_all(struct host1x *host)
{
        struct host1x_channel_list *chlist = &host->channel_list;
        int bit;

        mutex_lock(&chlist->lock);

        for_each_set_bit(bit, chlist->allocated_channels, host->info->nb_channels)
                host1x_channel_stop(&chlist->channels[bit]);

        mutex_unlock(&chlist->lock);
}

static void release_channel(struct kref *kref)
{
        struct host1x_channel *channel =
                container_of(kref, struct host1x_channel, refcount);
        struct host1x *host = dev_get_drvdata(channel->dev->parent);
        struct host1x_channel_list *chlist = &host->channel_list;

        host1x_hw_cdma_stop(host, &channel->cdma);
        host1x_cdma_deinit(&channel->cdma);

        clear_bit(channel->id, chlist->allocated_channels);
}

void host1x_channel_put(struct host1x_channel *channel)
{
        kref_put(&channel->refcount, release_channel);
}
EXPORT_SYMBOL(host1x_channel_put);

static struct host1x_channel *acquire_unused_channel(struct host1x *host)
{
        struct host1x_channel_list *chlist = &host->channel_list;
        unsigned int max_channels = host->info->nb_channels;
        unsigned int index;

        mutex_lock(&chlist->lock);

        index = find_first_zero_bit(chlist->allocated_channels, max_channels);
        if (index >= max_channels) {
                mutex_unlock(&chlist->lock);
                dev_err(host->dev, "failed to find free channel\n");
                return NULL;
        }

        chlist->channels[index].id = index;

        set_bit(index, chlist->allocated_channels);

        mutex_unlock(&chlist->lock);

        return &chlist->channels[index];
}

/**
 * host1x_channel_request() - Allocate a channel
 * @client: Host1x client this channel will be used to send commands to
 *
 * Allocates a new host1x channel for @client. May return NULL if CDMA
 * initialization fails.
 */
struct host1x_channel *host1x_channel_request(struct host1x_client *client)
{
        struct host1x *host = dev_get_drvdata(client->dev->parent);
        struct host1x_channel_list *chlist = &host->channel_list;
        struct host1x_channel *channel;
        int err;

        channel = acquire_unused_channel(host);
        if (!channel)
                return NULL;

        kref_init(&channel->refcount);
        mutex_init(&channel->submitlock);
        channel->client = client;
        channel->dev = client->dev;

        err = host1x_hw_channel_init(host, channel, channel->id);
        if (err < 0)
                goto fail;

        err = host1x_cdma_init(&channel->cdma);
        if (err < 0)
                goto fail;

        return channel;

fail:
        clear_bit(channel->id, chlist->allocated_channels);

        dev_err(client->dev, "failed to initialize channel\n");

        return NULL;
}
EXPORT_SYMBOL(host1x_channel_request);