/*******************************************************************************
    Copyright (c) 2019-2020 NVidia Corporation

    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 AUTHORS OR COPYRIGHT HOLDERS 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 "nvlink.h"
#include "nvlink_export.h"
#include "nvlink_os.h"
#include "../nvlink_ctx.h"
#include "../nvlink_helper.h"
#include "nvlink_lock.h"

/**
 * TODO: Rework this function to acquire locks and update callers
 *
 * Check if the device has no links registered
 *
 * @param[in]  dev  NVLink Device pointer
 *
 * return NV_TRUE if the device has no links registered
 */
NvBool
nvlink_lib_is_link_list_empty
(
    nvlink_device *dev
)
{
    NvBool isEmpty = NV_TRUE;

    isEmpty = nvListIsEmpty(&dev->link_list);

    return isEmpty;
}

/**
 * Get the link associated with the given link id.
 *
 * @param[in]   device   NVLink Device Pointer
 * @param[in]   link_id  Link Id of the given link
 * @param[out]  link     NVLink Link pointer
 *
 * return NVL_SUCCESS on success
 */
NvlStatus
nvlink_lib_get_link
(
    nvlink_device  *device,
    NvU32           link_id,
    nvlink_link   **link
)
{
    nvlink_link *cur    = NULL;
    NvlStatus    status = -NVL_NOT_FOUND;

    if (device == NULL || link == NULL)
    {
        return -NVL_BAD_ARGS;
    }

    *link = NULL;

    // Acquire the top-level lock
    status = nvlink_lib_top_lock_acquire();
    if (status != NVL_SUCCESS)
    {
        NVLINK_PRINT((DBG_MODULE_NVLINK_CORE, NVLINK_DBG_LEVEL_ERRORS,
            "%s: Failed to acquire top-level lock\n",
            __FUNCTION__));

        return status;
    }

    //
    // Top-level lock is now acquired. Proceed to traversing the 
    // link list for the device
    //

    // Reset status to -NVL_NOT_FOUND
    status = -NVL_NOT_FOUND;

    FOR_EACH_LINK_REGISTERED(cur, device, node)
    {
        if (cur->linkNumber == link_id)
        {
            *link  = cur;
            status = NVL_SUCCESS;
            break;
        }
    }

    // Release the top level-lock
    nvlink_lib_top_lock_release();

    return status;
}

/**
 * Set the given link as the link master.
 *   This requires that the remote end of the link is known, and that it
 *   hasn't set itself to be the master.
 *
 *   Note: This function is used by RM to set master attribute to a link
 *         in order to handle GPU lock inversion problem while servicing
 *         link interrupts(re-training). With external fabric management
 *         enabled, we don't have the issue. Also we don't have to worry
 *         about the inter-node connections which are managed by FM.
 *
 * @param[in]  link  NVLink Link pointer
 *
 * return NVL_SUCCESS if the master was set
 */
NvlStatus
nvlink_lib_set_link_master
(
    nvlink_link *link
)
{
    nvlink_link           *remote_end = NULL;
    NvlStatus              status     = NVL_SUCCESS;
    nvlink_intranode_conn *conn       = NULL;
    nvlink_link           *links[2]   = {0};
    NvU32                  numLinks   = 0;

    if (link == NULL)
    {
        NVLINK_PRINT((DBG_MODULE_NVLINK_CORE, NVLINK_DBG_LEVEL_ERRORS,
            "%s: Bad link pointer specified.\n",
            __FUNCTION__));
        return NVL_ERR_GENERIC;
    }

    // Acquire the top-level lock
    status = nvlink_lib_top_lock_acquire();
    if (status != NVL_SUCCESS)
    {
        NVLINK_PRINT((DBG_MODULE_NVLINK_CORE, NVLINK_DBG_LEVEL_ERRORS,
            "%s: Failed to acquire top-level lock\n",
            __FUNCTION__));

        return status;
    }

    //
    // Top-level lock is now acquired. Proceed to traversing the 
    // connection list
    //

    links[numLinks] = link;
    numLinks++;

    nvlink_core_get_intranode_conn(link, &conn);
    if (conn != NULL)
    {
        remote_end      = (conn->end0 == link ? conn->end1 : conn->end0);
        links[numLinks] = remote_end;
        numLinks++;
    }

    // Acquire the per-link locks for all links captured
    status = nvlink_lib_link_locks_acquire(links, numLinks);
    if (status != NVL_SUCCESS)
    {
        NVLINK_PRINT((DBG_MODULE_NVLINK_CORE, NVLINK_DBG_LEVEL_ERRORS,
            "%s: Failed to acquire per-link locks\n",
            __FUNCTION__));

        // Release the top-level lock
        nvlink_lib_top_lock_release();

        return status;
    }

    //
    // All the required per-link locks are successfully acquired
    // The connection list traversal is also complete now
    // Release the top level-lock
    //
    nvlink_lib_top_lock_release();

    // Early return if we've already done this
    if (link->master)
    {
        status = NVL_SUCCESS;
    }
    else
    {
        // Make sure the remote end exists and hasn't claimed the master yet
        if (remote_end == NULL || remote_end->master)
        {
            status = NVL_ERR_INVALID_STATE;
        }
        else
        {
            link->master = NV_TRUE;
        }
    }

    // Release the per-link locks
    nvlink_lib_link_locks_release(links, numLinks);

    return status;
}

/**
 * Get the link master associated with the given link.
 *   This may be the given link, or it may be the remote end. In the case
 *   when no master is assigned or the remote end is not known, this will
 *   return an error.
 *
 * @param[in]  link    NVLink Link pointer
 * @param[out] master  Master endpoint for the link
 *
 * return NVL_SUCCESS if the master was found
 */
NvlStatus
nvlink_lib_get_link_master
(
    nvlink_link  *link,
    nvlink_link **master
)
{
    nvlink_link           *remote_end = NULL;
    nvlink_intranode_conn *conn       = NULL;
    NvlStatus              status     = NVL_SUCCESS;
    nvlink_link           *links[2]   = {0};
    NvU32                  numLinks   = 0;

    if (link == NULL || master == NULL)
    {
        NVLINK_PRINT((DBG_MODULE_NVLINK_CORE, NVLINK_DBG_LEVEL_ERRORS,
            "%s: Bad link pointer specified.\n",
            __FUNCTION__));
        return NVL_ERR_GENERIC;
    }

    // Acquire the top-level lock
    status = nvlink_lib_top_lock_acquire();
    if (status != NVL_SUCCESS)
    {
        NVLINK_PRINT((DBG_MODULE_NVLINK_CORE, NVLINK_DBG_LEVEL_ERRORS,
            "%s: Failed to acquire top-level lock\n",
            __FUNCTION__));

        return status;
    }

    //
    // Top-level lock is now acquired. Proceed to traversing the 
    // connection list
    //

    links[numLinks] = link;
    numLinks++;

    nvlink_core_get_intranode_conn(link, &conn);
    if (conn != NULL)
    {
        remote_end      = (conn->end0 == link ? conn->end1 : conn->end0);
        links[numLinks] = remote_end;
        numLinks++;
    }

    // Acquire the per-link locks for all links captured
    status = nvlink_lib_link_locks_acquire(links, numLinks);
    if (status != NVL_SUCCESS)
    {
        NVLINK_PRINT((DBG_MODULE_NVLINK_CORE, NVLINK_DBG_LEVEL_ERRORS,
            "%s: Failed to acquire per-link locks\n",
            __FUNCTION__));

        // Release the top-level lock
        nvlink_lib_top_lock_release();

        return status;
    }

    //
    // All the required per-link locks are successfully acquired
    // The connection list traversal is also complete now
    // Release the top level-lock
    //
    nvlink_lib_top_lock_release();

    if (link->master)
    {
        *master = link;
    }
    else
    {
        // Make sure the remote end exists and hasn't claimed the master yet
        if (remote_end == NULL)
        {
            status = NVL_ERR_INVALID_STATE;
        }

        *master = remote_end;
    }

    // Release the per-link locks
    nvlink_lib_link_locks_release(links, numLinks);

    return status;
}

/**
 * Set whether the link is using ALI for training.
 * 
 * @param[in]  link       NVLink Link pointer
 * @param[in]  enableALI  Boolean for whether the link is using
 *                        ALI to train the link
 *
 * return NvlSuccess if setting the variable was successful.
 */
NvlStatus
nvlink_lib_link_set_training_mode
(
    nvlink_link  *link,
    NvBool        enableALI
)
{
    NvlStatus status = NVL_SUCCESS;
    if (link == NULL)
    {
        NVLINK_PRINT((DBG_MODULE_NVLINK_CORE, NVLINK_DBG_LEVEL_ERRORS,
            "%s: Bad link pointer specified.\n",
            __FUNCTION__));
        return NVL_ERR_GENERIC;
    }

    // Acquire the top-level lock
    status = nvlink_lib_top_lock_acquire();
    if (status != NVL_SUCCESS)
    {
        NVLINK_PRINT((DBG_MODULE_NVLINK_CORE, NVLINK_DBG_LEVEL_ERRORS,
            "%s: Failed to acquire top-level lock\n",
            __FUNCTION__));

        return status;
    }


    // Acquire the per-link lock
    status = nvlink_lib_link_locks_acquire(&link, 1);
    if (status != NVL_SUCCESS)
    {
        NVLINK_PRINT((DBG_MODULE_NVLINK_CORE, NVLINK_DBG_LEVEL_ERRORS,
            "%s: Failed to acquire per-link locks\n",
            __FUNCTION__));

        // Release the top-level lock
        nvlink_lib_top_lock_release();

        return status;
    }

    //
    // All the required per-link locks are successfully acquired
    // The connection list traversal is also complete now
    // Release the top level-lock
    //
    nvlink_lib_top_lock_release();

    // TODO: Add Setter for per-link enableALI state variable

    // Release the per-link lock
    nvlink_lib_link_locks_release(&link, 1);

    return status;
}
