/**************************************************************************
 *
 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
 * 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, sub license, 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 (including the
 * next paragraph) 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 NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS 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 <sys/cdefs.h>
#include <dev/drm2/drmP.h>
#include <dev/drm2/ttm/ttm_memory.h>
#include <dev/drm2/ttm/ttm_module.h>
#include <dev/drm2/ttm/ttm_page_alloc.h>

#define TTM_MEMORY_ALLOC_RETRIES 4

struct ttm_mem_zone {
        u_int kobj_ref;
        struct ttm_mem_global *glob;
        const char *name;
        uint64_t zone_mem;
        uint64_t emer_mem;
        uint64_t max_mem;
        uint64_t swap_limit;
        uint64_t used_mem;
};

MALLOC_DEFINE(M_TTM_ZONE, "ttm_zone", "TTM Zone");

static void ttm_mem_zone_kobj_release(struct ttm_mem_zone *zone)
{

        printf("[TTM] Zone %7s: Used memory at exit: %llu kiB\n",
                zone->name, (unsigned long long)zone->used_mem >> 10);
        free(zone, M_TTM_ZONE);
}

#if 0
/* XXXKIB sysctl */
static ssize_t ttm_mem_zone_show(struct ttm_mem_zone *zone;
                                 struct attribute *attr,
                                 char *buffer)
{
        uint64_t val = 0;

        mtx_lock(&zone->glob->lock);
        if (attr == &ttm_mem_sys)
                val = zone->zone_mem;
        else if (attr == &ttm_mem_emer)
                val = zone->emer_mem;
        else if (attr == &ttm_mem_max)
                val = zone->max_mem;
        else if (attr == &ttm_mem_swap)
                val = zone->swap_limit;
        else if (attr == &ttm_mem_used)
                val = zone->used_mem;
        mtx_unlock(&zone->glob->lock);

        return snprintf(buffer, PAGE_SIZE, "%llu\n",
                        (unsigned long long) val >> 10);
}
#endif

static void ttm_check_swapping(struct ttm_mem_global *glob);

#if 0
/* XXXKIB sysctl */
static ssize_t ttm_mem_zone_store(struct ttm_mem_zone *zone,
                                  struct attribute *attr,
                                  const char *buffer,
                                  size_t size)
{
        int chars;
        unsigned long val;
        uint64_t val64;

        chars = sscanf(buffer, "%lu", &val);
        if (chars == 0)
                return size;

        val64 = val;
        val64 <<= 10;

        mtx_lock(&zone->glob->lock);
        if (val64 > zone->zone_mem)
                val64 = zone->zone_mem;
        if (attr == &ttm_mem_emer) {
                zone->emer_mem = val64;
                if (zone->max_mem > val64)
                        zone->max_mem = val64;
        } else if (attr == &ttm_mem_max) {
                zone->max_mem = val64;
                if (zone->emer_mem < val64)
                        zone->emer_mem = val64;
        } else if (attr == &ttm_mem_swap)
                zone->swap_limit = val64;
        mtx_unlock(&zone->glob->lock);

        ttm_check_swapping(zone->glob);

        return size;
}
#endif

static void ttm_mem_global_kobj_release(struct ttm_mem_global *glob)
{
}

static bool ttm_zones_above_swap_target(struct ttm_mem_global *glob,
                                        bool from_wq, uint64_t extra)
{
        unsigned int i;
        struct ttm_mem_zone *zone;
        uint64_t target;

        for (i = 0; i < glob->num_zones; ++i) {
                zone = glob->zones[i];

                if (from_wq)
                        target = zone->swap_limit;
                else if (priv_check(curthread, PRIV_VM_MLOCK) == 0)
                        target = zone->emer_mem;
                else
                        target = zone->max_mem;

                target = (extra > target) ? 0ULL : target;

                if (zone->used_mem > target)
                        return true;
        }
        return false;
}

/**
 * At this point we only support a single shrink callback.
 * Extend this if needed, perhaps using a linked list of callbacks.
 * Note that this function is reentrant:
 * many threads may try to swap out at any given time.
 */

static void ttm_shrink(struct ttm_mem_global *glob, bool from_wq,
                       uint64_t extra)
{
        int ret;
        struct ttm_mem_shrink *shrink;

        mtx_lock(&glob->lock);
        if (glob->shrink == NULL)
                goto out;

        while (ttm_zones_above_swap_target(glob, from_wq, extra)) {
                shrink = glob->shrink;
                mtx_unlock(&glob->lock);
                ret = shrink->do_shrink(shrink);
                mtx_lock(&glob->lock);
                if (unlikely(ret != 0))
                        goto out;
        }
out:
        mtx_unlock(&glob->lock);
}



static void ttm_shrink_work(void *arg, int pending __unused)
{
        struct ttm_mem_global *glob = arg;

        ttm_shrink(glob, true, 0ULL);
}

static int ttm_mem_init_kernel_zone(struct ttm_mem_global *glob,
    uint64_t mem)
{
        struct ttm_mem_zone *zone;

        zone = malloc(sizeof(*zone), M_TTM_ZONE, M_WAITOK | M_ZERO);

        zone->name = "kernel";
        zone->zone_mem = mem;
        zone->max_mem = mem >> 1;
        zone->emer_mem = (mem >> 1) + (mem >> 2);
        zone->swap_limit = zone->max_mem - (mem >> 3);
        zone->used_mem = 0;
        zone->glob = glob;
        glob->zone_kernel = zone;
        refcount_init(&zone->kobj_ref, 1);
        glob->zones[glob->num_zones++] = zone;
        return 0;
}

static int ttm_mem_init_dma32_zone(struct ttm_mem_global *glob,
    uint64_t mem)
{
        struct ttm_mem_zone *zone;

        zone = malloc(sizeof(*zone), M_TTM_ZONE, M_WAITOK | M_ZERO);

        /**
         * No special dma32 zone needed.
         */

        if (mem <= ((uint64_t) 1ULL << 32)) {
                free(zone, M_TTM_ZONE);
                return 0;
        }

        /*
         * Limit max dma32 memory to 4GB for now
         * until we can figure out how big this
         * zone really is.
         */

        mem = ((uint64_t) 1ULL << 32);
        zone->name = "dma32";
        zone->zone_mem = mem;
        zone->max_mem = mem >> 1;
        zone->emer_mem = (mem >> 1) + (mem >> 2);
        zone->swap_limit = zone->max_mem - (mem >> 3);
        zone->used_mem = 0;
        zone->glob = glob;
        glob->zone_dma32 = zone;
        refcount_init(&zone->kobj_ref, 1);
        glob->zones[glob->num_zones++] = zone;
        return 0;
}

int ttm_mem_global_init(struct ttm_mem_global *glob)
{
        u_int64_t mem;
        int ret;
        int i;
        struct ttm_mem_zone *zone;

        mtx_init(&glob->lock, "ttmgz", NULL, MTX_DEF);
        glob->swap_queue = taskqueue_create("ttm_swap", M_WAITOK,
            taskqueue_thread_enqueue, &glob->swap_queue);
        taskqueue_start_threads(&glob->swap_queue, 1, PVM, "ttm swap");
        TASK_INIT(&glob->work, 0, ttm_shrink_work, glob);

        refcount_init(&glob->kobj_ref, 1);

        mem = physmem * PAGE_SIZE;

        ret = ttm_mem_init_kernel_zone(glob, mem);
        if (unlikely(ret != 0))
                goto out_no_zone;
        ret = ttm_mem_init_dma32_zone(glob, mem);
        if (unlikely(ret != 0))
                goto out_no_zone;
        for (i = 0; i < glob->num_zones; ++i) {
                zone = glob->zones[i];
                printf("[TTM] Zone %7s: Available graphics memory: %llu kiB\n",
                        zone->name, (unsigned long long)zone->max_mem >> 10);
        }
        ttm_page_alloc_init(glob, glob->zone_kernel->max_mem/(2*PAGE_SIZE));
        ttm_dma_page_alloc_init(glob, glob->zone_kernel->max_mem/(2*PAGE_SIZE));
        return 0;
out_no_zone:
        ttm_mem_global_release(glob);
        return ret;
}

void ttm_mem_global_release(struct ttm_mem_global *glob)
{
        unsigned int i;
        struct ttm_mem_zone *zone;

        /* let the page allocator first stop the shrink work. */
        ttm_page_alloc_fini();
        ttm_dma_page_alloc_fini();

        taskqueue_drain(glob->swap_queue, &glob->work);
        taskqueue_free(glob->swap_queue);
        glob->swap_queue = NULL;
        for (i = 0; i < glob->num_zones; ++i) {
                zone = glob->zones[i];
                if (refcount_release(&zone->kobj_ref))
                        ttm_mem_zone_kobj_release(zone);
        }
        if (refcount_release(&glob->kobj_ref))
                ttm_mem_global_kobj_release(glob);
}

static void ttm_check_swapping(struct ttm_mem_global *glob)
{
        bool needs_swapping = false;
        unsigned int i;
        struct ttm_mem_zone *zone;

        mtx_lock(&glob->lock);
        for (i = 0; i < glob->num_zones; ++i) {
                zone = glob->zones[i];
                if (zone->used_mem > zone->swap_limit) {
                        needs_swapping = true;
                        break;
                }
        }

        mtx_unlock(&glob->lock);

        if (unlikely(needs_swapping))
                taskqueue_enqueue(glob->swap_queue, &glob->work);

}

static void ttm_mem_global_free_zone(struct ttm_mem_global *glob,
                                     struct ttm_mem_zone *single_zone,
                                     uint64_t amount)
{
        unsigned int i;
        struct ttm_mem_zone *zone;

        mtx_lock(&glob->lock);
        for (i = 0; i < glob->num_zones; ++i) {
                zone = glob->zones[i];
                if (single_zone && zone != single_zone)
                        continue;
                zone->used_mem -= amount;
        }
        mtx_unlock(&glob->lock);
}

void ttm_mem_global_free(struct ttm_mem_global *glob,
                         uint64_t amount)
{
        return ttm_mem_global_free_zone(glob, NULL, amount);
}

static int ttm_mem_global_reserve(struct ttm_mem_global *glob,
                                  struct ttm_mem_zone *single_zone,
                                  uint64_t amount, bool reserve)
{
        uint64_t limit;
        int ret = -ENOMEM;
        unsigned int i;
        struct ttm_mem_zone *zone;

        mtx_lock(&glob->lock);
        for (i = 0; i < glob->num_zones; ++i) {
                zone = glob->zones[i];
                if (single_zone && zone != single_zone)
                        continue;

                limit = (priv_check(curthread, PRIV_VM_MLOCK) == 0) ?
                        zone->emer_mem : zone->max_mem;

                if (zone->used_mem > limit)
                        goto out_unlock;
        }

        if (reserve) {
                for (i = 0; i < glob->num_zones; ++i) {
                        zone = glob->zones[i];
                        if (single_zone && zone != single_zone)
                                continue;
                        zone->used_mem += amount;
                }
        }

        ret = 0;
out_unlock:
        mtx_unlock(&glob->lock);
        ttm_check_swapping(glob);

        return ret;
}


static int ttm_mem_global_alloc_zone(struct ttm_mem_global *glob,
                                     struct ttm_mem_zone *single_zone,
                                     uint64_t memory,
                                     bool no_wait, bool interruptible)
{
        int count = TTM_MEMORY_ALLOC_RETRIES;

        while (unlikely(ttm_mem_global_reserve(glob,
                                               single_zone,
                                               memory, true)
                        != 0)) {
                if (no_wait)
                        return -ENOMEM;
                if (unlikely(count-- == 0))
                        return -ENOMEM;
                ttm_shrink(glob, false, memory + (memory >> 2) + 16);
        }

        return 0;
}

int ttm_mem_global_alloc(struct ttm_mem_global *glob, uint64_t memory,
                         bool no_wait, bool interruptible)
{
        /**
         * Normal allocations of kernel memory are registered in
         * all zones.
         */

        return ttm_mem_global_alloc_zone(glob, NULL, memory, no_wait,
                                         interruptible);
}

#define page_to_pfn(pp) OFF_TO_IDX(VM_PAGE_TO_PHYS(pp))

int ttm_mem_global_alloc_page(struct ttm_mem_global *glob,
                              struct vm_page *page,
                              bool no_wait, bool interruptible)
{

        struct ttm_mem_zone *zone = NULL;

        /**
         * Page allocations may be registed in a single zone
         * only if highmem or !dma32.
         */

        if (glob->zone_dma32 && page_to_pfn(page) > 0x00100000UL)
                zone = glob->zone_kernel;
        return ttm_mem_global_alloc_zone(glob, zone, PAGE_SIZE, no_wait,
                                         interruptible);
}

void ttm_mem_global_free_page(struct ttm_mem_global *glob, struct vm_page *page)
{
        struct ttm_mem_zone *zone = NULL;

        if (glob->zone_dma32 && page_to_pfn(page) > 0x00100000UL)
                zone = glob->zone_kernel;
        ttm_mem_global_free_zone(glob, zone, PAGE_SIZE);
}


size_t ttm_round_pot(size_t size)
{
        if ((size & (size - 1)) == 0)
                return size;
        else if (size > PAGE_SIZE)
                return PAGE_ALIGN(size);
        else {
                size_t tmp_size = 4;

                while (tmp_size < size)
                        tmp_size <<= 1;

                return tmp_size;
        }
        return 0;
}