// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/******************************************************************************
 *
 * Module Name: utcache - local cache allocation routines
 *
 * Copyright (C) 2000 - 2021, Intel Corp.
 *
 *****************************************************************************/

#include <acpi/acpi.h>
#include "accommon.h"

#define _COMPONENT          ACPI_UTILITIES
ACPI_MODULE_NAME("utcache")

#ifdef ACPI_USE_LOCAL_CACHE
/*******************************************************************************
 *
 * FUNCTION:    acpi_os_create_cache
 *
 * PARAMETERS:  cache_name      - Ascii name for the cache
 *              object_size     - Size of each cached object
 *              max_depth       - Maximum depth of the cache (in objects)
 *              return_cache    - Where the new cache object is returned
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Create a cache object
 *
 ******************************************************************************/
acpi_status
acpi_os_create_cache(char *cache_name,
                     u16 object_size,
                     u16 max_depth, struct acpi_memory_list **return_cache)
{
        struct acpi_memory_list *cache;

        ACPI_FUNCTION_ENTRY();

        if (!cache_name || !return_cache || !object_size) {
                return (AE_BAD_PARAMETER);
        }

        /* Create the cache object */

        cache = acpi_os_allocate(sizeof(struct acpi_memory_list));
        if (!cache) {
                return (AE_NO_MEMORY);
        }

        /* Populate the cache object and return it */

        memset(cache, 0, sizeof(struct acpi_memory_list));
        cache->list_name = cache_name;
        cache->object_size = object_size;
        cache->max_depth = max_depth;

        *return_cache = cache;
        return (AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_os_purge_cache
 *
 * PARAMETERS:  cache           - Handle to cache object
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Free all objects within the requested cache.
 *
 ******************************************************************************/

acpi_status acpi_os_purge_cache(struct acpi_memory_list *cache)
{
        void *next;
        acpi_status status;

        ACPI_FUNCTION_ENTRY();

        if (!cache) {
                return (AE_BAD_PARAMETER);
        }

        status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
        if (ACPI_FAILURE(status)) {
                return (status);
        }

        /* Walk the list of objects in this cache */

        while (cache->list_head) {

                /* Delete and unlink one cached state object */

                next = ACPI_GET_DESCRIPTOR_PTR(cache->list_head);
                ACPI_FREE(cache->list_head);

                cache->list_head = next;
                cache->current_depth--;
        }

        (void)acpi_ut_release_mutex(ACPI_MTX_CACHES);
        return (AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_os_delete_cache
 *
 * PARAMETERS:  cache           - Handle to cache object
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Free all objects within the requested cache and delete the
 *              cache object.
 *
 ******************************************************************************/

acpi_status acpi_os_delete_cache(struct acpi_memory_list *cache)
{
        acpi_status status;

        ACPI_FUNCTION_ENTRY();

        /* Purge all objects in the cache */

        status = acpi_os_purge_cache(cache);
        if (ACPI_FAILURE(status)) {
                return (status);
        }

        /* Now we can delete the cache object */

        acpi_os_free(cache);
        return (AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_os_release_object
 *
 * PARAMETERS:  cache       - Handle to cache object
 *              object      - The object to be released
 *
 * RETURN:      None
 *
 * DESCRIPTION: Release an object to the specified cache. If cache is full,
 *              the object is deleted.
 *
 ******************************************************************************/

acpi_status acpi_os_release_object(struct acpi_memory_list *cache, void *object)
{
        acpi_status status;

        ACPI_FUNCTION_ENTRY();

        if (!cache || !object) {
                return (AE_BAD_PARAMETER);
        }

        /* If cache is full, just free this object */

        if (cache->current_depth >= cache->max_depth) {
                ACPI_FREE(object);
                ACPI_MEM_TRACKING(cache->total_freed++);
        }

        /* Otherwise put this object back into the cache */

        else {
                status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
                if (ACPI_FAILURE(status)) {
                        return (status);
                }

                /* Mark the object as cached */

                memset(object, 0xCA, cache->object_size);
                ACPI_SET_DESCRIPTOR_TYPE(object, ACPI_DESC_TYPE_CACHED);

                /* Put the object at the head of the cache list */

                ACPI_SET_DESCRIPTOR_PTR(object, cache->list_head);
                cache->list_head = object;
                cache->current_depth++;

                (void)acpi_ut_release_mutex(ACPI_MTX_CACHES);
        }

        return (AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_os_acquire_object
 *
 * PARAMETERS:  cache           - Handle to cache object
 *
 * RETURN:      the acquired object. NULL on error
 *
 * DESCRIPTION: Get an object from the specified cache. If cache is empty,
 *              the object is allocated.
 *
 ******************************************************************************/

void *acpi_os_acquire_object(struct acpi_memory_list *cache)
{
        acpi_status status;
        void *object;

        ACPI_FUNCTION_TRACE(os_acquire_object);

        if (!cache) {
                return_PTR(NULL);
        }

        status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
        if (ACPI_FAILURE(status)) {
                return_PTR(NULL);
        }

        ACPI_MEM_TRACKING(cache->requests++);

        /* Check the cache first */

        if (cache->list_head) {

                /* There is an object available, use it */

                object = cache->list_head;
                cache->list_head = ACPI_GET_DESCRIPTOR_PTR(object);

                cache->current_depth--;

                ACPI_MEM_TRACKING(cache->hits++);
                ACPI_DEBUG_PRINT_RAW((ACPI_DB_EXEC,
                                      "%s: Object %p from %s cache\n",
                                      ACPI_GET_FUNCTION_NAME, object,
                                      cache->list_name));

                status = acpi_ut_release_mutex(ACPI_MTX_CACHES);
                if (ACPI_FAILURE(status)) {
                        return_PTR(NULL);
                }

                /* Clear (zero) the previously used Object */

                memset(object, 0, cache->object_size);
        } else {
                /* The cache is empty, create a new object */

                ACPI_MEM_TRACKING(cache->total_allocated++);

#ifdef ACPI_DBG_TRACK_ALLOCATIONS
                if ((cache->total_allocated - cache->total_freed) >
                    cache->max_occupied) {
                        cache->max_occupied =
                            cache->total_allocated - cache->total_freed;
                }
#endif

                /* Avoid deadlock with ACPI_ALLOCATE_ZEROED */

                status = acpi_ut_release_mutex(ACPI_MTX_CACHES);
                if (ACPI_FAILURE(status)) {
                        return_PTR(NULL);
                }

                object = ACPI_ALLOCATE_ZEROED(cache->object_size);
                if (!object) {
                        return_PTR(NULL);
                }
        }

        return_PTR(object);
}
#endif                          /* ACPI_USE_LOCAL_CACHE */