/**

  * $Id: xltcache.c,v 1.2 2007-09-04 08:32:44 nkeynes Exp $

  * 

  * Translation cache management. This part is architecture independent.

  *

  * Copyright (c) 2005 Nathan Keynes.

  *

  * This program is free software; you can redistribute it and/or modify

  * it under the terms of the GNU General Public License as published by

  * the Free Software Foundation; either version 2 of the License, or

  * (at your option) any later version.

  *

  * This program is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  * GNU General Public License for more details.

  */

 #include "sh4/xltcache.h"

 #include "dreamcast.h"

 #include <sys/mman.h>

 #include <assert.h>

 #define XLAT_LUT_PAGE_BITS 12

 #define XLAT_LUT_TOTAL_BITS 28

 #define XLAT_LUT_PAGE(addr) (((addr)>>13) & 0xFFFF)

 #define XLAT_LUT_ENTRY(addr) (((addr)&0x1FFE) >> 1)

 #define XLAT_LUT_PAGES (1<<(XLAT_LUT_TOTAL_BITS-XLAT_LUT_PAGE_BITS))

 #define XLAT_LUT_PAGE_ENTRIES (1<<XLAT_LUT_PAGE_BITS)

 #define XLAT_LUT_PAGE_SIZE (XLAT_LUT_PAGE_ENTRIES * sizeof(void *))

 #define XLAT_LUT_ENTRY_EMPTY (void *)0

 #define XLAT_LUT_ENTRY_USED  (void *)1

 #define NEXT(block) ( (xlat_cache_block_t)&((block)->code[(block)->size]))

 #define BLOCK_FOR_CODE(code) (((xlat_cache_block_t)code)-1)

 #define IS_ENTRY_POINT(ent) (ent > XLAT_LUT_ENTRY_USED)

 #define IS_ENTRY_USED(ent) (ent != XLAT_LUT_ENTRY_EMPTY)

 #define MIN_BLOCK_SIZE 32

 #define MIN_TOTAL_SIZE (sizeof(struct xlat_cache_block)+MIN_BLOCK_SIZE)

 #define BLOCK_INACTIVE 0

 #define BLOCK_ACTIVE 1

 #define BLOCK_USED 2

 xlat_cache_block_t xlat_new_cache;

 xlat_cache_block_t xlat_new_cache_ptr;

 xlat_cache_block_t xlat_new_create_ptr;

 xlat_cache_block_t xlat_temp_cache;

 xlat_cache_block_t xlat_temp_cache_ptr;

 xlat_cache_block_t xlat_old_cache;

 xlat_cache_block_t xlat_old_cache_ptr;

 static void ***xlat_lut;

 static void **xlat_lut2; /* second-tier page info */

 void xlat_cache_init() 

 {

     xlat_new_cache = mmap( NULL, XLAT_NEW_CACHE_SIZE, PROT_EXEC|PROT_READ|PROT_WRITE,

 			   MAP_PRIVATE|MAP_ANONYMOUS, -1, 0 );

     xlat_temp_cache = mmap( NULL, XLAT_TEMP_CACHE_SIZE, PROT_EXEC|PROT_READ|PROT_WRITE,

 			   MAP_PRIVATE|MAP_ANONYMOUS, -1, 0 );

     xlat_old_cache = mmap( NULL, XLAT_OLD_CACHE_SIZE, PROT_EXEC|PROT_READ|PROT_WRITE,

 			   MAP_PRIVATE|MAP_ANONYMOUS, -1, 0 );

     xlat_new_cache_ptr = xlat_new_cache;

     xlat_temp_cache_ptr = xlat_temp_cache;

     xlat_old_cache_ptr = xlat_old_cache;

     xlat_new_create_ptr = xlat_new_cache;

     xlat_lut = mmap( NULL, XLAT_LUT_PAGES*sizeof(void *), PROT_READ|PROT_WRITE,

 		     MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);

     memset( xlat_lut, 0, XLAT_LUT_PAGES*sizeof(void *) );

     xlat_flush_cache();

 }

 /**

  * Reset the cache structure to its default state

  */

 void xlat_flush_cache() 

 {

     xlat_cache_block_t tmp;

     int i;

     xlat_new_cache_ptr = xlat_new_cache;

     xlat_new_cache_ptr->active = 0;

     xlat_new_cache_ptr->size = XLAT_NEW_CACHE_SIZE - 2*sizeof(struct xlat_cache_block);

     tmp = NEXT(xlat_new_cache_ptr);

     tmp->active = 1;

     tmp->size = 0;

     xlat_temp_cache_ptr = xlat_temp_cache;

     xlat_temp_cache_ptr->active = 0;

     xlat_temp_cache_ptr->size = XLAT_TEMP_CACHE_SIZE - 2*sizeof(struct xlat_cache_block);

     tmp = NEXT(xlat_temp_cache_ptr);

     tmp->active = 1;

     tmp->size = 0;

     xlat_old_cache_ptr = xlat_old_cache;

     xlat_old_cache_ptr->active = 0;

     xlat_old_cache_ptr->size = XLAT_OLD_CACHE_SIZE - 2*sizeof(struct xlat_cache_block);

     tmp = NEXT(xlat_old_cache_ptr);

     tmp->active = 1;

     tmp->size = 0;

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

 	if( xlat_lut[i] != NULL ) {

 	    memset( xlat_lut[i], 0, XLAT_LUT_PAGE_SIZE );

 	}

     }

 }

 void xlat_flush_page( sh4addr_t address )

 {

     int i;

     void **page = xlat_lut[XLAT_LUT_PAGE(address)];

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

 	if( IS_ENTRY_POINT(page[i]) ) {

 	    BLOCK_FOR_CODE(page[i])->active = 0;

 	}

 	page[i] = NULL;

     }

 }

 void *xlat_get_code( sh4addr_t address )

 {

     void **page = xlat_lut[XLAT_LUT_PAGE(address)];

     if( page == NULL ) {

 	return NULL;

     }

     return page[XLAT_LUT_ENTRY(address)];

 }

 uint32_t xlat_get_block_size( void *block )

 {

     xlat_cache_block_t xlt = (xlat_cache_block_t)(((char *)block)-sizeof(struct xlat_cache_block));

     return xlt->size;

 }

 /**

  * Cut the specified block so that it has the given size, with the remaining data

  * forming a new free block. If the free block would be less than the minimum size,

  * the cut is not performed.

  * @return the next block after the (possibly cut) block.

  */

 static inline xlat_cache_block_t xlat_cut_block( xlat_cache_block_t block, int cutsize )

 {

     if( block->size > cutsize + MIN_TOTAL_SIZE ) {

 	int oldsize = block->size;

 	block->size = cutsize;

 	xlat_cache_block_t next = NEXT(block);

 	next->active = 0;

 	next->size = oldsize - cutsize - sizeof(struct xlat_cache_block);

 	return next;

     } else {

 	return NEXT(block);

     }

 }

 /**

  * Promote a block in temp space (or elsewhere for that matter) to old space.

  *

  * @param block to promote.

  */

 static void xlat_promote_to_old_space( xlat_cache_block_t block )

 {

     int allocation = -sizeof(struct xlat_cache_block);

     int size = block->size;

     xlat_cache_block_t curr = xlat_old_cache_ptr;

     xlat_cache_block_t start_block = curr;

     do {

 	allocation += curr->size + sizeof(struct xlat_cache_block);

 	curr = NEXT(curr);

 	if( allocation > size ) {

 	    break; /* done */

 	}

 	if( curr->size == 0 ) { /* End-of-cache Sentinel */

 	    /* Leave what we just released as free space and start again from the

 	     * top of the cache

 	     */

 	    start_block->active = 0;

 	    start_block->size = allocation;

 	    allocation = -sizeof(struct xlat_cache_block);

 	    start_block = curr = xlat_old_cache;

 	}

     } while(1);

     start_block->active = 1;

     start_block->size = allocation;

     start_block->lut_entry = block->lut_entry;

     *block->lut_entry = &start_block->code;

     memcpy( start_block->code, block->code, block->size );

     xlat_old_cache_ptr = xlat_cut_block(start_block, size );

     if( xlat_old_cache_ptr->size == 0 ) {

 	xlat_old_cache_ptr = xlat_old_cache;

     }

 }

 /**

  * Similarly to the above method, promotes a block to temp space.

  * TODO: Try to combine these - they're nearly identical

  */

 void xlat_promote_to_temp_space( xlat_cache_block_t block )

 {

     int size = block->size;

     int allocation = -sizeof(struct xlat_cache_block);

     xlat_cache_block_t curr = xlat_temp_cache_ptr;

     xlat_cache_block_t start_block = curr;

     do {

 	if( curr->active == BLOCK_USED ) {

 	    xlat_promote_to_old_space( curr );

 	}

 	allocation += curr->size + sizeof(struct xlat_cache_block);

 	curr = NEXT(curr);

 	if( allocation > size ) {

 	    break; /* done */

 	}

 	if( curr->size == 0 ) { /* End-of-cache Sentinel */

 	    /* Leave what we just released as free space and start again from the

 	     * top of the cache

 	     */

 	    start_block->active = 0;

 	    start_block->size = allocation;

 	    allocation = -sizeof(struct xlat_cache_block);

 	    start_block = curr = xlat_temp_cache;

 	}

     } while(1);

     start_block->active = 1;

     start_block->size = allocation;

     start_block->lut_entry = block->lut_entry;

     *block->lut_entry = &start_block->code;

     memcpy( start_block->code, block->code, block->size );

     xlat_temp_cache_ptr = xlat_cut_block(start_block, size );

     if( xlat_temp_cache_ptr->size == 0 ) {

 	xlat_temp_cache_ptr = xlat_temp_cache;

     }

 }

 /**

  * Returns the next block in the new cache list that can be written to by the

  * translator. If the next block is active, it is evicted first.

  */

 xlat_cache_block_t xlat_start_block( sh4addr_t address )

 {

     if( xlat_new_cache_ptr->size == 0 ) {

 	xlat_new_cache_ptr = xlat_new_cache;

     }

     if( xlat_new_cache_ptr->active ) {

 	xlat_promote_to_temp_space( xlat_new_cache_ptr );

     }

     xlat_new_create_ptr = xlat_new_cache_ptr;

     xlat_new_create_ptr->active = 1;

     xlat_new_cache_ptr = NEXT(xlat_new_cache_ptr);

     /* Add the LUT entry for the block */

     if( xlat_lut[XLAT_LUT_PAGE(address)] == NULL ) {

 	xlat_lut[XLAT_LUT_PAGE(address)] =

 	    mmap( NULL, XLAT_LUT_PAGE_SIZE, PROT_READ|PROT_WRITE,

 		  MAP_PRIVATE|MAP_ANONYMOUS, -1, 0 );

 	memset( xlat_lut[XLAT_LUT_PAGE(address)], 0, XLAT_LUT_PAGE_SIZE );

     }

     if( IS_ENTRY_POINT(xlat_lut[XLAT_LUT_PAGE(address)][XLAT_LUT_ENTRY(address)]) ) {

 	xlat_cache_block_t oldblock = BLOCK_FOR_CODE(xlat_lut[XLAT_LUT_PAGE(address)][XLAT_LUT_ENTRY(address)]);

 	oldblock->active = 0;

     }

     xlat_lut[XLAT_LUT_PAGE(address)][XLAT_LUT_ENTRY(address)] = 

 	&xlat_new_create_ptr->code;

     xlat_new_create_ptr->lut_entry = xlat_lut[XLAT_LUT_PAGE(address)] + XLAT_LUT_ENTRY(address);

     return xlat_new_create_ptr;

 }

 xlat_cache_block_t xlat_extend_block()

 {

     if( xlat_new_cache_ptr->size == 0 ) {

 	/* Migrate to the front of the cache to keep it contiguous */

 	xlat_new_create_ptr->active = 0;

 	char *olddata = xlat_new_create_ptr->code;

 	int oldsize = xlat_new_create_ptr->size;

 	int size = oldsize + MIN_BLOCK_SIZE; /* minimum expansion */

 	void **lut_entry = xlat_new_create_ptr->lut_entry;

 	int allocation = -sizeof(struct xlat_cache_block);

 	xlat_new_cache_ptr = xlat_new_cache;

 	do {

 	    if( xlat_new_cache_ptr->active ) {

 		xlat_promote_to_temp_space( xlat_new_cache_ptr );

 	    }

 	    allocation += xlat_new_cache_ptr->size + sizeof(struct xlat_cache_block);

 	    xlat_new_cache_ptr = NEXT(xlat_new_cache_ptr);

 	} while( allocation < size );

 	xlat_new_create_ptr = xlat_new_cache;

 	xlat_new_create_ptr->active = 1;

 	xlat_new_create_ptr->size = allocation;

 	xlat_new_create_ptr->lut_entry = lut_entry;

 	*lut_entry = &xlat_new_create_ptr->code;

 	memmove( xlat_new_create_ptr->code, olddata, oldsize );

     } else {

 	if( xlat_new_cache_ptr->active ) {

 	    xlat_promote_to_temp_space( xlat_new_cache_ptr );

 	}

 	xlat_new_create_ptr->size += xlat_new_cache_ptr->size + sizeof(struct xlat_cache_block);

 	xlat_new_cache_ptr = NEXT(xlat_new_cache_ptr);

     }

     return xlat_new_create_ptr;

 }

 void xlat_commit_block( uint32_t destsize, uint32_t srcsize )

 {

     void **ptr = xlat_new_create_ptr->lut_entry;

     void **endptr = ptr + (srcsize>>2);

     while( ptr < endptr ) {

 	if( *ptr == NULL ) {

 	    *ptr = XLAT_LUT_ENTRY_USED;

 	}

 	ptr++;

     }

     xlat_new_cache_ptr = xlat_cut_block( xlat_new_create_ptr, destsize );

 }

 void xlat_delete_block( xlat_cache_block_t block ) 

 {

     block->active = 0;

     *block->lut_entry = NULL;

 }

 void xlat_check_cache_integrity( xlat_cache_block_t cache, xlat_cache_block_t ptr, int size )

 {

     int foundptr = 0;

     xlat_cache_block_t tail = 

 	(xlat_cache_block_t)(((char *)cache) + size - sizeof(struct xlat_cache_block));

     assert( tail->active == 1 );

     assert( tail->size == 0 ); 

     while( cache < tail ) {

 	assert( cache->active >= 0 && cache->active <= 2 );

 	assert( cache->size >= 0 && cache->size < size );

 	if( cache == ptr ) {

 	    foundptr = 1;

 	}

 	cache = NEXT(cache);

     }

     assert( cache == tail );

     assert( foundptr == 1 );

 }

 void xlat_check_integrity( )

 {

     xlat_check_cache_integrity( xlat_new_cache, xlat_new_cache_ptr, XLAT_NEW_CACHE_SIZE );

     xlat_check_cache_integrity( xlat_temp_cache, xlat_temp_cache_ptr, XLAT_TEMP_CACHE_SIZE );

     xlat_check_cache_integrity( xlat_old_cache, xlat_old_cache_ptr, XLAT_OLD_CACHE_SIZE );

 }