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/*

 * Copyright (C) 2001-2005 Jakub Jermar

 * Copyright (C) 2005 Sergey Bondari

 * 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.

 */

/*

 * Locking order

 *

 * In order to access particular zone, the process must first lock

 * the zones.lock, then lock the zone and then unlock the zones.lock.

 * This insures, that we can fiddle with the zones in runtime without

 * affecting the processes. 

 *

 */

#include <typedefs.h>

#include <arch/types.h>

#include <mm/frame.h>

#include <mm/as.h>

#include <panic.h>

#include <debug.h>

#include <adt/list.h>

#include <synch/spinlock.h>

#include <arch/asm.h>

#include <arch.h>

#include <print.h>

#include <align.h>

#include <mm/slab.h>

typedef struct {

	count_t refcount;	/**< tracking of shared frames  */

	__u8 buddy_order;	/**< buddy system block order */

	link_t buddy_link;	/**< link to the next free block inside one order */

	void *parent;           /**< If allocated by slab, this points there */

}frame_t;

typedef struct {

	SPINLOCK_DECLARE(lock);	/**< this lock protects everything below */

	pfn_t base;	/**< frame_no of the first frame in the frames array */

	count_t count;          /**< Size of zone */

	frame_t *frames;	/**< array of frame_t structures in this zone */

	count_t free_count;	/**< number of free frame_t structures */

	count_t busy_count;	/**< number of busy frame_t structures */

	buddy_system_t * buddy_system; /**< buddy system for the zone */

	int flags;

}zone_t;

/*

 * The zoneinfo.lock must be locked when accessing zoneinfo structure.

 * Some of the attributes in zone_t structures are 'read-only'

 */

struct {

	SPINLOCK_DECLARE(lock);

	int count;

	zone_t *info[ZONES_MAX];

}zones;

/*********************************/

/* Helper functions */

static inline index_t frame_index(zone_t *zone, frame_t *frame)

{

	return (index_t)(frame - zone->frames);

}

static inline index_t frame_index_abs(zone_t *zone, frame_t *frame)

{

	return (index_t)(frame - zone->frames) + zone->base;

}

static inline int frame_index_valid(zone_t *zone, index_t index)

{

	return index >= 0 && index < zone->count;

}

/** Compute pfn_t from frame_t pointer & zone pointer */

static index_t make_frame_index(zone_t *zone, frame_t *frame)

{

	return frame - zone->frames;

}

/** Initialize frame structure

 *

 * Initialize frame structure.

 *

 * @param frame Frame structure to be initialized.

 */

static void frame_initialize(frame_t *frame)

{

	frame->refcount = 1;

	frame->buddy_order = 0;

}

/*************************************/

/* Zoneinfo functions */

/**

 * Insert-sort zone into zones list

 */

static void zones_add_zone(zone_t *zone)

{

	int i;

	spinlock_lock(&zones.lock);

	/* Try to merge */

	if (zone->flags & ZONE_JOIN) {

		for (i=0; i < zones.count; i++) {

			spinlock_lock(&zones.info[i]->lock);

			/* Join forward, join backward */

			panic("Not implemented");

			spinlock_unlock(&zones.info[i]->lock);

		}

		spinlock_unlock(&zones.lock);

	} else {

		if (zones.count+1 == ZONES_MAX)

			panic("Maximum zone(%d) count exceeded.", ZONES_MAX);

		zones.info[zones.count++] = zone;

	}

	spinlock_unlock(&zones.lock);

}

/**

 * Try to find a zone where can we find the frame

 *

 * @param hint Start searching in zone 'hint'

 * @param lock Lock zone if true

 *

 * Assume interrupts disable

 */

static zone_t * find_zone_and_lock(pfn_t frame, int *pzone)

{

	int i;

	int hint = pzone ? *pzone : 0;

	zone_t *z;

	spinlock_lock(&zones.lock);

	if (hint >= zones.count || hint < 0)

		hint = 0;

	i = hint;

	do {

		z = zones.info[i];

		spinlock_lock(&z->lock);

		if (z->base <= frame && z->base + z->count > frame) {

			spinlock_unlock(&zones.lock); /* Unlock the global lock */

			if (pzone)

				*pzone = i;

			return z;

		}

		spinlock_unlock(&z->lock);

		i++;

		if (i >= zones.count)

			i = 0;

	} while(i != hint);

	spinlock_unlock(&zones.lock);

	return NULL;

}

/**

 * Find AND LOCK zone that can allocate order frames

 *

 * Assume interrupts are disabled!!

 *

 * @param pzone Pointer to preferred zone or NULL, on return contains zone number

 */

static zone_t * find_free_zone_lock(__u8 order, int *pzone)

{

	int i;

	zone_t *z;

	int hint = pzone ? *pzone : 0;

	spinlock_lock(&zones.lock);

	if (hint >= zones.count)

		hint = 0;

	i = hint;

	do {

		z = zones.info[i];

		spinlock_lock(&z->lock);

		/* Check if the zone has 2^order frames area available  */

		if (buddy_system_can_alloc(z->buddy_system, order)) {

			spinlock_unlock(&zones.lock);

			if (pzone)

				*pzone = i;

			return z;

		}

		spinlock_unlock(&z->lock);

		if (++i >= zones.count)

			i = 0;

	} while(i != hint);

	spinlock_unlock(&zones.lock);

	return NULL;

}

/********************************************/

/* Buddy system functions */

/** Buddy system find_block implementation

 *

 * Find block that is parent of current list.

 * That means go to lower addresses, until such block is found

 *

 * @param order - Order of parent must be different then this parameter!!

 */

static link_t *zone_buddy_find_block(buddy_system_t *b, link_t *child,

				     __u8 order)

{

	frame_t * frame;

	zone_t * zone;

	index_t index;

	frame = list_get_instance(child, frame_t, buddy_link);

	zone = (zone_t *) b->data;

	index = frame_index(zone, frame);

	do {

		if (zone->frames[index].buddy_order != order) {

			return &zone->frames[index].buddy_link;

		}

	} while(index-- > 0);

	return NULL;

}

/** 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

 */

static link_t * zone_buddy_find_buddy(buddy_system_t *b, link_t * block) 

{

	frame_t * frame;

	zone_t * zone;

	index_t index;

	bool is_left, is_right;

	frame = list_get_instance(block, frame_t, buddy_link);

	zone = (zone_t *) b->data;

	ASSERT(IS_BUDDY_ORDER_OK(frame_index_abs(zone, frame), frame->buddy_order));

	is_left = IS_BUDDY_LEFT_BLOCK_ABS(zone, frame);

	is_right = IS_BUDDY_RIGHT_BLOCK_ABS(zone, frame);

	ASSERT(is_left ^ is_right);

	if (is_left) {

		index = (frame_index(zone, frame)) + (1 << frame->buddy_order);

	} else { // if (is_right)

		index = (frame_index(zone, frame)) - (1 << frame->buddy_order);

	}

	if (frame_index_valid(zone, index)) {

		if (zone->frames[index].buddy_order == frame->buddy_order && 

		    zone->frames[index].refcount == 0) {

			return &zone->frames[index].buddy_link;

		}

	}

	return NULL;	

}

/** Buddy system bisect implementation

 *

 * @param b Buddy system.

 * @param block Block to bisect

 *

 * @return right block

 */

static 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_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)

 */

static 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

 */

static 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

 */

static __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;

}

/** Buddy system mark_busy implementation

 *

 * @param b Buddy system

 * @param block Buddy system block

 *

 */

static void zone_buddy_mark_busy(buddy_system_t *b, link_t * block) {

	frame_t * frame;

	frame = list_get_instance(block, frame_t, buddy_link);

	frame->refcount = 1;

}

/** Buddy system mark_available implementation

 *

 * @param b Buddy system

 * @param block Buddy system block

 *

 */

static void zone_buddy_mark_available(buddy_system_t *b, link_t * block) {

	frame_t * frame;

	frame = list_get_instance(block, frame_t, buddy_link);

	frame->refcount = 0;

}

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,

	.mark_busy = zone_buddy_mark_busy,

	.mark_available = zone_buddy_mark_available,

	.find_block = zone_buddy_find_block

};

/*************************************/

/* Zone functions */

/** Allocate frame in particular zone

 *

 * Assume zone is locked

 *

 * @return Frame index in zone

 */

static pfn_t zone_frame_alloc(zone_t *zone,__u8 order, int flags, int *status)

{

	pfn_t v;

	link_t *tmp;

	frame_t *frame;

	/* Allocate frames from zone buddy system */

	tmp = buddy_system_alloc(zone->buddy_system, order);

	ASSERT(tmp);

	/* Update zone information. */

	zone->free_count -= (1 << order);

	zone->busy_count += (1 << order);

	/* Frame will be actually a first frame of the block. */

	frame = list_get_instance(tmp, frame_t, buddy_link);

	/* get frame address */

	v = make_frame_index(zone, frame);

	return v;

}

/** Free frame from zone

 *

 * Assume zone is locked

 */

static void zone_frame_free(zone_t *zone, index_t frame_idx)

{

	frame_t *frame;

	__u8 order;

	frame = &zone->frames[frame_idx];

	/* remember frame order */

	order = frame->buddy_order;

	ASSERT(frame->refcount);

	if (!--frame->refcount) {

		buddy_system_free(zone->buddy_system, &frame->buddy_link);

	}

	/* Update zone information. */

	zone->free_count += (1 << order);

	zone->busy_count -= (1 << order);

}

/** Return frame from zone */

static frame_t * zone_get_frame(zone_t *zone, index_t frame_idx)

{

	ASSERT(frame_idx < zone->count);

	return &zone->frames[frame_idx];

}

/** Mark frame in zone unavailable to allocation */

static void zone_mark_unavailable(zone_t *zone, index_t frame_idx)

{

	frame_t *frame;

	link_t *link;

	frame = zone_get_frame(zone, frame_idx);

	link = buddy_system_alloc_block(zone->buddy_system, 

					&frame->buddy_link);

	ASSERT(link);

	zone->free_count--;

}

/** 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 conffram Address of configuration frame

 * @param flags Zone flags.

 *

 * @return Initialized zone.

 */

static zone_t * zone_construct(pfn_t start, count_t count, 

			       zone_t *z, int flags)

{

	int i;

	__u8 max_order;

	spinlock_initialize(&z->lock, "zone_lock");

	z->base = start;

	z->count = count;

	z->flags = flags;

	z->free_count = count;

	z->busy_count = 0;

	/*

	 * Compute order for buddy system, initialize

	 */

	for (max_order = 0; count >> max_order; max_order++)

		;

	z->buddy_system = (buddy_system_t *)&z[1];

	buddy_system_create(z->buddy_system, max_order, 

			    &zone_buddy_system_operations, 

			    (void *) z);

	/* Allocate frames _after_ the conframe */

	/* Check sizes */

	z->frames = (frame_t *)((void *)z->buddy_system+buddy_conf_size(max_order));

	for (i = 0; i<count; i++) {

		frame_initialize(&z->frames[i]);

	}

	/* Stuffing frames */

	for (i = 0; i < count; i++) {

		z->frames[i].refcount = 0;

		buddy_system_free(z->buddy_system, &z->frames[i].buddy_link);

	}

	return z;

}

/** Compute configuration data size for zone */

__address zone_conf_size(pfn_t start, count_t count)

{

	int size = sizeof(zone_t) + count*sizeof(frame_t);

	int max_order;

	for (max_order = 0; count >> max_order; max_order++)

		;

	size += buddy_conf_size(max_order);

	return size;

}

/** Create and add zone to system

 *

 * @param confframe Where configuration frame is supposed to be.

 *                  Always check, that we will not disturb the kernel and possibly init. 

 *                  If confframe is given _outside_ this zone, it is expected,

 *                  that the area is already marked BUSY and big enough

 *                  to contain zone_conf_size() amount of data

 */

void zone_create(pfn_t start, count_t count, pfn_t confframe, int flags)

{

	zone_t *z;

	__address addr,endaddr;

	count_t confcount;

	int i;

	/* Theoretically we could have here 0, practically make sure

	 * nobody tries to do that. If some platform requires, remove

	 * the assert

	 */

	ASSERT(confframe);

	/* If conframe is supposed to be inside our zone, then make sure

	 * it does not span kernel & init

	 */

	confcount = SIZE2FRAMES(zone_conf_size(start,count));

	if (confframe >= start && confframe < start+count) {

		for (;confframe < start+count;confframe++) {

			addr = PFN2ADDR(confframe);

			endaddr =  PFN2ADDR (confframe + confcount);

			if (overlaps(addr, endaddr, KA2PA(config.base),

				     KA2PA(config.base+config.kernel_size)))

				continue;

			if (config.init_addr)

				if (overlaps(addr,endaddr, 

					     KA2PA(config.init_addr),

					     KA2PA(config.init_addr+config.init_size)))

					continue;

			break;

		}

		if (confframe >= start+count)

			panic("Cannot find configuration data for zone.");

	}

	z = zone_construct(start, count, (zone_t *)PA2KA(PFN2ADDR(confframe)), flags);

	zones_add_zone(z);

	/* If confdata in zone, mark as unavailable */

	if (confframe >= start && confframe < start+count)

		for (i=confframe; i<confframe+confcount; i++) {

			zone_mark_unavailable(z, i - z->base);

		}

}

/***************************************/

/* Frame functions */

/** Set parent of frame */

void frame_set_parent(pfn_t pfn, void *data, int hint)

{

	zone_t *zone = find_zone_and_lock(pfn, &hint);

	ASSERT(zone);

	zone_get_frame(zone, pfn-zone->base)->parent = data;

	spinlock_unlock(&zone->lock);

}

void * frame_get_parent(pfn_t pfn, int hint)

{

	zone_t *zone = find_zone_and_lock(pfn, &hint);

	void *res;

	ASSERT(zone);

	res = zone_get_frame(zone, pfn - zone->base)->parent;

	spinlock_unlock(&zone->lock);

	return res;

}

/** Allocate power-of-two frames of physical memory.

 *

 * @param flags Flags for host zone selection and address processing.

 * @param order Allocate exactly 2^order frames.

 * @param pzone Preferred zone

 *

 * @return Allocated frame.

 */

pfn_t frame_alloc_generic(__u8 order, int flags, int * status, int *pzone) 

{

	ipl_t ipl;

	int freed;

	pfn_t v;

	zone_t *zone;

loop:

	ipl = interrupts_disable();

	/*

	 * First, find suitable frame zone.

	 */

	zone = find_free_zone_lock(order,pzone);

	/* If no memory, reclaim some slab memory,

	   if it does not help, reclaim all */

	if (!zone && !(flags & FRAME_NO_RECLAIM)) {

		freed = slab_reclaim(0);

		if (freed)

			zone = find_free_zone_lock(order,pzone);

		if (!zone) {

			freed = slab_reclaim(SLAB_RECLAIM_ALL);

			if (freed)

				zone = find_free_zone_lock(order,pzone);

		}

	}

	if (!zone) {

		if (flags & FRAME_PANIC)

			panic("Can't allocate frame.\n");

		/*

		 * TODO: Sleep until frames are available again.

		 */

		interrupts_restore(ipl);

		if (flags & FRAME_ATOMIC) {

			ASSERT(status != NULL);

			if (status)

				*status = FRAME_NO_MEMORY;

			return NULL;

		}

		panic("Sleep not implemented.\n");

		goto loop;

	}

	v = zone_frame_alloc(zone,order,flags,status);

	v += zone->base;

	spinlock_unlock(&zone->lock);

	interrupts_restore(ipl);

	if (status)

		*status = FRAME_OK;

	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 frame Frame no to be freed.

 */

void frame_free(pfn_t pfn)

{

	ipl_t ipl;

	zone_t *zone;

	ipl = interrupts_disable();

	/*

	 * First, find host frame zone for addr.

	 */

	zone = find_zone_and_lock(pfn,NULL);

	ASSERT(zone);

	zone_frame_free(zone, pfn-zone->base);

	spinlock_unlock(&zone->lock);

	interrupts_restore(ipl);

}

/** Mark given range unavailable in frame zones */

void frame_mark_unavailable(pfn_t start, count_t count)

{

	int i;

	zone_t *zone;

	int prefzone = 0;

	for (i=0; i<count; i++) {

		zone = find_zone_and_lock(start+i,&prefzone);

		if (!zone) /* PFN not found */

			continue;

		zone_mark_unavailable(zone, start+i-zone->base);

		spinlock_unlock(&zone->lock);

	}

}

/** Initialize physical memory management

 *

 * Initialize physical memory managemnt.

 */

void frame_init(void)

{

	if (config.cpu_active == 1) {

		zones.count = 0;

		spinlock_initialize(&zones.lock,"zones_glob_lock");

	}

	/* Tell the architecture to create some memory */

	frame_arch_init();

	if (config.cpu_active == 1) {

		frame_mark_unavailable(ADDR2PFN(KA2PA(config.base)),

				       SIZE2FRAMES(config.kernel_size));

		if (config.init_size > 0)

			frame_mark_unavailable(ADDR2PFN(KA2PA(config.init_addr)),

					       SIZE2FRAMES(config.init_size));

	}

}

/** Prints list of zones

 *

 */

void zone_print_list(void) {

	zone_t *zone = NULL;

	int i;

	ipl_t ipl;

	ipl = interrupts_disable();

	spinlock_lock(&zones.lock);

	printf("Base address\tFree Frames\tBusy Frames\n");

	printf("------------\t-----------\t-----------\n");

	for (i=0;i<zones.count;i++) {

		zone = zones.info[i];

		spinlock_lock(&zone->lock);

		printf("%L\t%d\t\t%d\n",PFN2ADDR(zone->base), 

		       zone->free_count, zone->busy_count);

		spinlock_unlock(&zone->lock);

	}

	spinlock_unlock(&zones.lock);

	interrupts_restore(ipl);

}

/** Prints zone details

 *

 * @param base Zone base address

 */

void zone_print_one(int znum) {

	zone_t *zone = NULL;

	ipl_t ipl;

	ipl = interrupts_disable();

	spinlock_lock(&zones.lock);

	if (znum >= zones.count || znum < 0) {

		printf("Zone number out of bounds.\n");

		spinlock_unlock(&zones.lock);

		interrupts_restore(ipl);

		return;

	}

	zone = zones.info[znum];

	spinlock_lock(&zone->lock);

	printf("Memory zone information\n\n");

	printf("Zone base address: %P\n", PFN2ADDR(zone->base));

	printf("Zone size: %d frames (%dK)\n", zone->count, ((zone->count) * FRAME_SIZE) >> 10);

	printf("Allocated space: %d frames (%dK)\n", zone->busy_count, (zone->busy_count * FRAME_SIZE) >> 10);

	printf("Available space: %d (%dK)\n", zone->free_count, (zone->free_count * FRAME_SIZE) >> 10);

	printf("\nBuddy allocator structures:\n\n");

	buddy_system_structure_print(zone->buddy_system, FRAME_SIZE);

	spinlock_unlock(&zone->lock);

	spinlock_unlock(&zones.lock);

	interrupts_restore(ipl);

}