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/*
 * Copyright (C) 2001-2004 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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 <typedefs.h>
#include <arch/types.h>
#include <mm/heap.h>
#include <mm/frame.h>
#include <mm/vm.h>
#include <panic.h>
#include <debug.h>
#include <list.h>
#include <synch/spinlock.h>
#include <arch/asm.h>
#include <arch.h>

spinlock_t zone_head_lock;       /**< this lock protects zone_head list */
link_t zone_head;                /**< list of all zones in the system */

static struct buddy_system_operations  zone_buddy_system_operations = {
    .find_buddy = zone_buddy_find_buddy,
    .bisect = zone_buddy_bisect,
    .coalesce = zone_buddy_coalesce,
    .set_order = zone_buddy_set_order,
    .get_order = zone_buddy_get_order,
};

/** Initialize physical memory management
 *
 * Initialize physical memory managemnt.
 */
void frame_init(void)
{
    if (config.cpu_active == 1) {
        zone_init();
    }

    frame_arch_init();
    
    if (config.cpu_active == 1) {
                frame_region_not_free(config.base, config.base + config.kernel_size + CONFIG_STACK_SIZE);
        }   
}

/** Allocate a frame
 *
 * Allocate a frame of physical memory.
 *
 * @param flags Flags for host zone selection and address processing.
 *
 * @return Allocated frame.
 */
__address frame_alloc(int flags)
{
    ipl_t ipl;
    link_t *cur, *tmp;
    zone_t *z;
    zone_t *zone = NULL;
    frame_t *frame = NULL;
    __address v;
    
loop:
    ipl = interrupts_disable();
    spinlock_lock(&zone_head_lock);
    
    /*
     * First, find suitable frame zone.
     */
    for (cur = zone_head.next; cur != &zone_head; cur = cur->next) {
        z = list_get_instance(cur, zone_t, link);
        
        spinlock_lock(&z->lock);
        /*
         * Check if the zone has any free frames.
         */
        if (z->free_count) {
            zone = z;
            break;
        }
        spinlock_unlock(&z->lock);
    }
    
    if (!zone) {
        if (flags & FRAME_PANIC)
            panic("Can't allocate frame.\n");
        
        /*
         * TODO: Sleep until frames are available again.
         */
        spinlock_unlock(&zone_head_lock);
        interrupts_restore(ipl);

        panic("Sleep not implemented.\n");
        goto loop;
    }
        
    tmp = zone->free_head.next;
    frame = list_get_instance(tmp, frame_t, link);

    frame->refcount++;
    list_remove(tmp);           /* remove frame from free_head */
    zone->free_count--;
    zone->busy_count++;
    
    //v = zone->base + (frame - zone->frames) * FRAME_SIZE;
    v = FRAME2ADDR(zone, frame);
    
    if (flags & FRAME_KA)
        v = PA2KA(v);
    
    spinlock_unlock(&zone->lock);
    
    spinlock_unlock(&zone_head_lock);
    interrupts_restore(ipl);
    
    return v;
}

/** Free a frame.
 *
 * Find respective frame structrue for supplied addr.
 * Decrement frame reference count.
 * If it drops to zero, move the frame structure to free list.
 *
 * @param addr Address of the frame to be freed. It must be a multiple of FRAME_SIZE.
 */
void frame_free(__address addr)
{
    ipl_t ipl;
    link_t *cur;
    zone_t *z;
    zone_t *zone = NULL;
    frame_t *frame;
    
    ASSERT(addr % FRAME_SIZE == 0);
    
    ipl = interrupts_disable();
    spinlock_lock(&zone_head_lock);
    
    /*
     * First, find host frame zone for addr.
     */
    for (cur = zone_head.next; cur != &zone_head; cur = cur->next) {
        z = list_get_instance(cur, zone_t, link);
        
        spinlock_lock(&z->lock);
        
        if (IS_KA(addr))
            addr = KA2PA(addr);
        
        /*
         * Check if addr belongs to z.
         */
        if ((addr >= z->base) && (addr <= z->base + (z->free_count + z->busy_count) * FRAME_SIZE)) {
            zone = z;
            break;
        }
        spinlock_unlock(&z->lock);
    }
    
    ASSERT(zone != NULL);
    
    frame = ADDR2FRAME(zone, addr);
    // frame = &zone->frames[(addr - zone->base)/FRAME_SIZE];
    ASSERT(frame->refcount);

    if (!--frame->refcount) {
        list_append(&frame->link, &zone->free_head);    /* append frame to free_head */
        zone->free_count++;
        zone->busy_count--;
    }
    
    spinlock_unlock(&zone->lock);   
    
    spinlock_unlock(&zone_head_lock);
    interrupts_restore(ipl);
}

/** Mark frame not free.
 *
 * Find respective frame structrue for supplied addr.
 * Increment frame reference count and remove the frame structure from free list.
 *
 * @param addr Address of the frame to be marked. It must be a multiple of FRAME_SIZE.
 */
void frame_not_free(__address addr)
{
    ipl_t ipl;
    link_t *cur;
    zone_t *z;
    zone_t *zone = NULL;
    frame_t *frame;
    
    ASSERT(addr % FRAME_SIZE == 0);
    
    ipl = interrupts_disable();
    spinlock_lock(&zone_head_lock);
    
    /*
     * First, find host frame zone for addr.
     */
    for (cur = zone_head.next; cur != &zone_head; cur = cur->next) {
        z = list_get_instance(cur, zone_t, link);
        
        spinlock_lock(&z->lock);
        
        if (IS_KA(addr))
            addr = KA2PA(addr);
        
        /*
         * Check if addr belongs to z.
         */
        if ((addr >= z->base) && (addr <= z->base + (z->free_count + z->busy_count) * FRAME_SIZE)) {
            zone = z;
            break;
        }
        spinlock_unlock(&z->lock);
    }
    
    ASSERT(zone != NULL);
    
    //frame = &zone->frames[(addr - zone->base)/FRAME_SIZE];
    frame = ADDR2FRAME(zone, addr);

    if (!frame->refcount) {
        frame->refcount++;

        list_remove(&frame->link);          /* remove frame from free_head */
        zone->free_count--;
        zone->busy_count++;
    }
    
    spinlock_unlock(&zone->lock);   
    
    spinlock_unlock(&zone_head_lock);
    interrupts_restore(ipl);
}

/** Mark frame region not free.
 *
 * Mark frame region not free.
 *
 * @param start First address.
 * @param stop Last address.
 */
void frame_region_not_free(__address start, __address stop)
{
        __address a;

        start /= FRAME_SIZE;
        stop /= FRAME_SIZE;
        for (a = start; a <= stop; a++)
                frame_not_free(a * FRAME_SIZE);
}


/** Initialize zonekeeping
 *
 * Initialize zonekeeping.
 */
void zone_init(void)
{
    spinlock_initialize(&zone_head_lock);
    list_initialize(&zone_head);
}

/** Create frame zone
 *
 * Create new frame zone.
 *
 * @param start Physical address of the first frame within the zone.
 * @param size Size of the zone. Must be a multiple of FRAME_SIZE.
 * @param flags Zone flags.
 *
 * @return Initialized zone.
 */
zone_t *zone_create(__address start, size_t size, int flags)
{
    zone_t *z;
    count_t cnt;
    int i;
    __u8 max_order;
    
    ASSERT(start % FRAME_SIZE == 0);
    ASSERT(size % FRAME_SIZE == 0);
    
    cnt = size / FRAME_SIZE;
    
    z = (zone_t *) early_malloc(sizeof(zone_t));
    if (z) {
        link_initialize(&z->link);
        spinlock_initialize(&z->lock);
    
        z->base = start;
        z->flags = flags;

        z->free_count = cnt;
        list_initialize(&z->free_head);

        z->busy_count = 0;
        
        z->frames = (frame_t *) early_malloc(cnt * sizeof(frame_t));
        if (!z->frames) {
            early_free(z);
            return NULL;
        }
        
        for (i = 0; i<cnt; i++) {
            frame_initialize(&z->frames[i], z);
            list_append(&z->frames[i].link, &z->free_head);
        }
        
        /*
         * Create buddy system for the zone
         */
        for (max_order = 0; cnt >> max_order; max_order++);
        z->buddy_system = buddy_system_create(max_order, &zone_buddy_system_operations, (void *) z);
    }
    
    return z;
}

/** Attach frame zone
 *
 * Attach frame zone to zone list.
 *
 * @param zone Zone to be attached.
 */
void zone_attach(zone_t *zone)
{
    ipl_t ipl;
    
    ipl = interrupts_disable();
    spinlock_lock(&zone_head_lock);
    
    list_append(&zone->link, &zone_head);
    
    spinlock_unlock(&zone_head_lock);
    interrupts_restore(ipl);
}

/** Initialize frame structure
 *
 * Initialize frame structure.
 *
 * @param frame Frame structure to be initialized.
 * @param zone Host frame zone.
 */
void frame_initialize(frame_t *frame, zone_t *zone)
{
    frame->refcount = 0;
    link_initialize(&frame->link);
}



/*
 * buddy system functions (under construction)
 * 
 */


/** Allocate 2^order frames
 *
 */
__address zone_buddy_frame_alloc(int flags, __u8 order) {
    ipl_t ipl;
    link_t *cur, *tmp;
    zone_t *z;
    zone_t *zone = NULL;
    frame_t *frame = NULL;
    __address v;
    
loop:
    ipl = interrupts_disable();
    spinlock_lock(&zone_head_lock);
    
    /*
     * First, find suitable frame zone.
     */
    for (cur = zone_head.next; cur != &zone_head; cur = cur->next) {
        z = list_get_instance(cur, zone_t, link);
        
        spinlock_lock(&z->lock);
        /*
         * Check if the zone has 2^order frames area available
         * TODO: Must check if buddy system has at least block in order >= given order
         */
        if (z->free_count == (1 >> order)) { 
            zone = z;
            break;
        }
        
        spinlock_unlock(&z->lock);
    }
    
    if (!zone) {
        if (flags & FRAME_PANIC)
            panic("Can't allocate frame.\n");
        
        /*
         * TODO: Sleep until frames are available again.
         */
        spinlock_unlock(&zone_head_lock);
        interrupts_restore(ipl);

        panic("Sleep not implemented.\n");
        goto loop;
    }
        

    /* Allocate frames from zone buddy system */
    cur = buddy_system_alloc(zone->buddy_system, order);
    
    /* frame will be actually a first frame of the block */
    frame = list_get_instance(cur, frame_t, buddy_link);
    
    /* get frame address */
    v = FRAME2ADDR(zone, frame);
    
    if (flags & FRAME_KA)
        v = PA2KA(v);
    
    spinlock_unlock(&zone->lock);
    spinlock_unlock(&zone_head_lock);
    interrupts_restore(ipl);
    
    return v;
}


/** Free frame(s)
 *
 * @param addr Address of the frame(s) to be freed. It must be a multiple of FRAME_SIZE.
 */
void zone_buddy_frame_free(__address addr)
{
    ipl_t ipl;
    link_t *cur;
    zone_t *z;
    zone_t *zone = NULL;
    frame_t *frame;
    
    ASSERT(addr % FRAME_SIZE == 0);
    
    ipl = interrupts_disable();
    spinlock_lock(&zone_head_lock);
    
    /*
     * First, find host frame zone for addr.
     */
    for (cur = zone_head.next; cur != &zone_head; cur = cur->next) {
        z = list_get_instance(cur, zone_t, link);
        
        spinlock_lock(&z->lock);
        
        if (IS_KA(addr))
            addr = KA2PA(addr);
        
        /*
         * Check if addr belongs to z.
         */
        if ((addr >= z->base) && (addr <= z->base + (z->free_count + z->busy_count) * FRAME_SIZE)) {
            zone = z;
            break;
        }
        spinlock_unlock(&z->lock);
    }
    
    ASSERT(zone != NULL);
    
    frame = ADDR2FRAME(zone, addr);

    ASSERT(frame->refcount);

    if (!--frame->refcount) {
        buddy_system_free(zone->buddy_system, &frame->buddy_link);
    }
    
    spinlock_unlock(&zone->lock);   
    
    spinlock_unlock(&zone_head_lock);
    interrupts_restore(ipl);
}

/** Guess zone by frame instance address
 *
 * @param frame Frame
 *
 * @return Zone of given frame
 */
zone_t * get_zone_by_frame(frame_t * frame) {
    link_t * cur;
    zone_t * zone, *z;

    ASSERT(frame);
    /*
     * First, find host frame zone for addr.
     */
    for (cur = zone_head.next; cur != &zone_head; cur = cur->next) {
        z = list_get_instance(cur, zone_t, link);
        
        spinlock_lock(&z->lock);
        
        /*
         * Check if frame address belongs to z.
         */
        if ((frame >= z->frames) && (frame <= z->frames + (z->free_count + z->busy_count))) {
            zone = z;
            break;
        }
        spinlock_unlock(&z->lock);
    }
    ASSERT(zone);
    
    return zone;


}

/** Buddy system find_buddy implementation
 *
 * @param b Buddy system.
 * @param block Block for which buddy should be found
 *
 * @return Buddy for given block if found
 */
link_t * zone_buddy_find_buddy(buddy_system_t *b, link_t * block) {
    frame_t * frame, * f;
    zone_t * zone;
    link_t * cur;
    bool is_left, is_right;

    frame = list_get_instance(block, frame_t, buddy_link);
    zone = get_zone_by_frame(frame);
    
    
    /* 
     * (FRAME_INDEX % 2^(ORDER+1)) == 0 ===> LEFT BUDDY 
     * (FRAME_INDEX % 2^(ORDER+1)) == 2^(ORDER) ===> RIGHT BUDDY
     */
     
    is_left = IS_BUDDY_LEFT_BLOCK(zone, frame);
    is_right = IS_BUDDY_RIGHT_BLOCK(zone, frame);
    
    ASSERT((is_left || is_right) && (!is_left || !is_right));
    
    for (cur = &zone->buddy_system->order[frame->buddy_order]; cur; cur = cur->next) {
        f = list_get_instance(cur, frame_t, buddy_link);
        
        ASSERT(f->buddy_order == frame->buddy_order);
        
        /* 
         * if found frame is coherent with our frame from the left 
         */
        if ((FRAME_INDEX(zone, f) + 1 >> frame->buddy_order == FRAME_INDEX(zone, frame)) && is_right) {
            return cur;
        }
        
        /* 
         * if found frame is coherent with our frame from the right 
         */
        if ((FRAME_INDEX(zone,f) - 1 >> frame->buddy_order == FRAME_INDEX(zone, frame)) && is_left) {
            return cur;
        }
        
    }
    
    return NULL;
    
    
}

/** Buddy system bisect implementation
 *
 * @param b Buddy system.
 * @param block Block to bisect
 *
 * @return right block
 */
link_t * zone_buddy_bisect(buddy_system_t *b, link_t * block) {
    frame_t * frame_l, * frame_r;
    
    frame_l = list_get_instance(block, frame_t, buddy_link);

    frame_r = (frame_t *) (&frame_l + (1>>frame_l->buddy_order-1));

    return &frame_r->buddy_link;
    
}

/** Buddy system coalesce implementation
 *
 * @param b Buddy system.
 * @param block_1 First block
 * @param block_2 First block's buddy
 *
 * @return Coalesced block (actually block that represents lower address)
 */
link_t * zone_buddy_coalesce(buddy_system_t *b, link_t * block_1, link_t * block_2) {
    frame_t * frame1, * frame2;
    
    frame1 = list_get_instance(block_1, frame_t, buddy_link);
    frame2 = list_get_instance(block_2, frame_t, buddy_link);
    
    return &frame1 < &frame2 ? block_1 : block_2;
}

/** Buddy system set_order implementation
 *
 * @param b Buddy system.
 * @param block Buddy system block
 * @param order Order to set
 */
void zone_buddy_set_order(buddy_system_t *b, link_t * block, __u8 order) {
    frame_t * frame;
    frame = list_get_instance(block, frame_t, buddy_link);
    frame->buddy_order = order;
}

/** Buddy system get_order implementation
 *
 * @param b Buddy system.
 * @param block Buddy system block
 *
 * @return Order of block
 */
__u8 zone_buddy_get_order(buddy_system_t *b, link_t * block) {
    frame_t * frame;
    frame = list_get_instance(block, frame_t, buddy_link);
    return frame->buddy_order;
}