/*-
 * Copyright 2016-2025 Microchip Technology, Inc. and/or its subsidiaries.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */


#include "smartpqi_includes.h"

#ifndef LOCKFREE_STACK

/*
 * Function used to release the tag from taglist.
 */
void
pqisrc_put_tag(pqi_taglist_t *taglist, uint32_t elem)
{

        OS_ACQUIRE_SPINLOCK(&(taglist->lock));
/*      DBG_FUNC("IN\n");*/

        ASSERT(taglist->num_elem < taglist->max_elem);

        if (taglist->num_elem < taglist->max_elem) {
                taglist->elem_array[taglist->tail] = elem;
                taglist->num_elem++;
                taglist->tail = (taglist->tail + 1) % taglist->max_elem;
        }

        OS_RELEASE_SPINLOCK(&taglist->lock);

/*      DBG_FUNC("OUT\n");*/
}

/*
 * Function used to get an unoccupied tag from the tag list.
 */
uint32_t
pqisrc_get_tag(pqi_taglist_t *taglist)
{
        uint32_t elem = INVALID_ELEM;

/*      DBG_FUNC("IN\n");*/

        OS_ACQUIRE_SPINLOCK(&taglist->lock);

        ASSERT(taglist->num_elem > 0);

        if (taglist->num_elem > 0) {
                elem = taglist->elem_array[taglist->head];
                taglist->num_elem--;
                taglist->head = (taglist->head + 1) % taglist->max_elem;
        }

        OS_RELEASE_SPINLOCK(&taglist->lock);

/*      DBG_FUNC("OUT got %d\n", elem);*/
        return elem;
}

/*
 * Initialize circular queue implementation of tag list.
 */
int
pqisrc_init_taglist(pqisrc_softstate_t *softs, pqi_taglist_t *taglist,
                                uint32_t max_elem)
{
        int ret = PQI_STATUS_SUCCESS;
        int i = 0;

        DBG_FUNC("IN\n");

        taglist->max_elem = max_elem;
        taglist->num_elem = 0;
        taglist->head = 0;
        taglist->tail = 0;
        taglist->elem_array = os_mem_alloc(softs,
                        (max_elem * sizeof(uint32_t)));
        if (!(taglist->elem_array)) {
                DBG_FUNC("Unable to allocate memory for taglist\n");
                ret = PQI_STATUS_FAILURE;
                goto err_out;
        }

    os_strlcpy(taglist->lockname, "tag_lock",  LOCKNAME_SIZE);
    ret = os_init_spinlock(softs, &taglist->lock, taglist->lockname);
    if(ret){
        DBG_ERR("tag lock initialization failed\n");
        taglist->lockcreated=false;
        goto err_lock;
        }
    taglist->lockcreated = true;

        /* indices 1 to max_elem are considered as valid tags */
        for (i=1; i <= max_elem; i++) {
                softs->rcb[i].tag = INVALID_ELEM;
                pqisrc_put_tag(taglist, i);
        }

        DBG_FUNC("OUT\n");
        return ret;

err_lock:
    os_mem_free(softs, (char *)taglist->elem_array,
        (taglist->max_elem * sizeof(uint32_t)));
        taglist->elem_array = NULL;
err_out:
        DBG_FUNC("OUT failed\n");
        return ret;
}

/*
 * Destroy circular queue implementation of tag list.
 */
void
pqisrc_destroy_taglist(pqisrc_softstate_t *softs, pqi_taglist_t *taglist)
{
        DBG_FUNC("IN\n");
        os_mem_free(softs, (char *)taglist->elem_array,
                (taglist->max_elem * sizeof(uint32_t)));
        taglist->elem_array = NULL;

    if(taglist->lockcreated==true){
        os_uninit_spinlock(&taglist->lock);
        taglist->lockcreated = false;
    }

        DBG_FUNC("OUT\n");
}

#else    /* LOCKFREE_STACK */

/*
 * Initialize circular queue implementation of tag list.
 */
int
pqisrc_init_taglist(pqisrc_softstate_t *softs, lockless_stack_t *stack,
                                uint32_t max_elem)
{
        int ret = PQI_STATUS_SUCCESS;
        int index = 0;

        DBG_FUNC("IN\n");

        /* indices 1 to max_elem are considered as valid tags */
        stack->max_elem = max_elem + 1;
        stack->head.data = 0;
        DBG_INFO("Stack head address :%p\n",&stack->head);

        /*Allocate memory for stack*/
        stack->next_index_array = (uint32_t*)os_mem_alloc(softs,
                (stack->max_elem * sizeof(uint32_t)));
        if (!(stack->next_index_array)) {
                DBG_ERR("Unable to allocate memory for stack\n");
                ret = PQI_STATUS_FAILURE;
                goto err_out;
        }

        /* push all the entries to the stack */
        for (index = 1; index < stack->max_elem ; index++) {
                softs->rcb[index].tag = INVALID_ELEM;
                pqisrc_put_tag(stack, index);
        }

        DBG_FUNC("OUT\n");
        return ret;
err_out:
        DBG_FUNC("Failed OUT\n");
        return ret;
}

/*
 * Destroy circular queue implementation of tag list.
 */
void
pqisrc_destroy_taglist(pqisrc_softstate_t *softs, lockless_stack_t *stack)
{
        DBG_FUNC("IN\n");

        /* de-allocate stack memory */
        if (stack->next_index_array) {
                os_mem_free(softs,(char*)stack->next_index_array,
                        (stack->max_elem * sizeof(uint32_t)));
                stack->next_index_array = NULL;
        }

        DBG_FUNC("OUT\n");
}

/*
 * Function used to release the tag from taglist.
 */
void
pqisrc_put_tag(lockless_stack_t *stack, uint32_t index)
{
   union head_list cur_head, new_head;

        DBG_FUNC("IN\n");
        DBG_INFO("push tag :%u\n",index);

        if (index >= stack->max_elem) {
                ASSERT(false);
                DBG_INFO("Pushed Invalid index\n"); /* stack full */
                return;
        }

        if (stack->next_index_array[index] != 0) {
                ASSERT(false);
                DBG_INFO("Index already present as tag in the stack\n");
                return;
        }

        do {
                cur_head = stack->head;
                /* increment seq_no */
                new_head.top.seq_no = cur_head.top.seq_no + 1;
                /* update the index at the top of the stack with the new index */
                new_head.top.index = index;
                /* Create a link to the previous index */
                stack->next_index_array[index] = cur_head.top.index;
        }while(!os_atomic64_cas(&stack->head.data,cur_head.data,new_head.data));
        stack->num_elem++;
        DBG_FUNC("OUT\n");
        return;
}

/*
 * Function used to get an unoccupied tag from the tag list.
 */
uint32_t
pqisrc_get_tag(lockless_stack_t *stack)
{
        union head_list cur_head, new_head;

        DBG_FUNC("IN\n");
        do {
                cur_head = stack->head;
                if (cur_head.top.index == 0)    /* stack empty */
                        return INVALID_ELEM;
                /* increment seq_no field */
                new_head.top.seq_no = cur_head.top.seq_no + 1;
                /* update the index at the top of the stack with the next index */
                new_head.top.index = stack->next_index_array[cur_head.top.index];
        }while(!os_atomic64_cas(&stack->head.data,cur_head.data,new_head.data));
        stack->next_index_array[cur_head.top.index] = 0;
        stack->num_elem--;

        DBG_INFO("pop tag: %u\n",cur_head.top.index);
        DBG_FUNC("OUT\n");
        return cur_head.top.index; /*tag*/
}
#endif /* LOCKFREE_STACK */