/*
 *   Creation Date: <1999/11/07 19:02:11 samuel>
 *   Time-stamp: <2004/01/07 19:42:36 samuel>
 *
 *	<ofmem.c>
 *
 *	OF Memory manager
 *
 *   Copyright (C) 1999-2004 Samuel Rydh (samuel@ibrium.se)
 *   Copyright (C) 2004 Stefan Reinauer
 *
 *   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
 *
 */

#include "openbios/config.h"
#include "openbios/bindings.h"
#include "libc/string.h"
#include "ofmem.h"
#include "kernel.h"
#include "mmutypes.h"
#include "asm/processor.h"

#define BIT(n)		(1U<<(31-(n)))

/* called from assembly */
extern void dsi_exception( void );
extern void isi_exception( void );
extern void setup_mmu( ulong code_base );

/*
 * From Apple's BootX source comments:
 *
 *  96 MB map (currently unused - 4363357 tracks re-adoption)
 * 00000000 - 00003FFF  : Exception Vectors
 * 00004000 - 03FFFFFF  : Kernel Image, Boot Struct and Drivers (~64 MB)
 * 04000000 - 04FFFFFF  : File Load Area (16 MB)   [80 MB]
 * 05000000 - 053FFFFF  : FS Cache    (4 MB)       [84 MB]
 * 05400000 - 055FFFFF  : Malloc Zone (2 MB)       [86 MB]
 * 05600000 - 057FFFFF  : BootX Image (2 MB)       [88 MB]
 * 05800000 - 05FFFFFF  : Unused/OF   (8 MB)       [96 MB]
 *
 */

#define FREE_BASE		0x00004000
#define OF_CODE_START	0xfff00000UL
#define IO_BASE			0x80000000
#define OFMEM			((ofmem_t*)0x05400000)

#define OF_MALLOC_BASE		((char*)OFMEM + ((sizeof(ofmem_t) + 3) & ~3))

#define HASH_SIZE		(2 << 15)

#define	SEGR_USER		BIT(2)
#define SEGR_BASE		0x0400

static inline ulong
get_hash_base( void )
{
	ulong sdr1;

	asm volatile("mfsdr1 %0" : "=r" (sdr1) );

	return (sdr1 & 0xffff0000);
}

static inline ulong
get_hash_size( void )
{
	ulong sdr1;

	asm volatile("mfsdr1 %0" : "=r" (sdr1) );

	return ((sdr1 << 16) | 0x0000ffff) + 1;
}

static inline ulong
get_rom_base( void )
{
	ofmem_t *ofmem = ofmem_arch_get_private();
	return ofmem->ramsize - 0x00100000;
}

ulong
get_ram_top( void )
{
	return get_rom_base() - HASH_SIZE - (32 + 32 + 64) * 1024;
}

ulong
get_ram_bottom( void )
{
        return (ulong)FREE_BASE;
}

static ucell get_heap_top( void )
{
	return get_hash_base() - (32 + 64) * 1024;
}

static inline size_t ALIGN_SIZE(size_t x, size_t a)
{
    return (x + a - 1) & ~(a-1);
}

ofmem_t* ofmem_arch_get_private(void)
{
	return OFMEM;
}

void* ofmem_arch_get_malloc_base(void)
{
	return OF_MALLOC_BASE;
}

ucell ofmem_arch_get_heap_top(void)
{
	return get_heap_top();
}

ucell ofmem_arch_get_virt_top(void)
{
	return IO_BASE;
}

void ofmem_arch_unmap_pages(ucell virt, ucell size)
{
	/* kill page mappings in provided range */
}

void ofmem_arch_early_map_pages(ucell phys, ucell virt, ucell size, ucell mode)
{
	/* none yet */
}

/************************************************************************/
/*	OF private allocations						*/
/************************************************************************/

void *
malloc( int size )
{
	return ofmem_malloc(size);
}

void
free( void *ptr )
{
	return ofmem_free(ptr);
}

void *
realloc( void *ptr, size_t size )
{
	return ofmem_realloc(ptr, size);
}


/************************************************************************/
/*	misc								*/
/************************************************************************/

extern char _start[], _end[];

ucell ofmem_arch_default_translation_mode( ucell phys )
{
	/* XXX: Guard bit not set as it should! */
	if( phys < IO_BASE )
		return 0x02;	/*0xa*/	/* wim GxPp */
	return 0x6a;		/* WIm GxPp, I/O */
}


/************************************************************************/
/*	page fault handler						*/
/************************************************************************/

static ucell
ea_to_phys( ucell ea, ucell *mode )
{
	ucell phys;

	if (ea >= OF_CODE_START) {
		/* ROM into RAM */
		ea -= OF_CODE_START;
		phys = get_rom_base() + ea;
		*mode = 0x02;
		return phys;
	}

	phys = ofmem_translate(ea, mode);
	if( phys == -1 ) {
		phys = ea;
		*mode = ofmem_arch_default_translation_mode( phys );

		/* print_virt_range(); */
		/* print_phys_range(); */
		/* print_trans(); */
	}
	return phys;
}

static void
hash_page_64( ucell ea, ucell phys, ucell mode )
{
	static int next_grab_slot=0;
	uint64_t vsid_mask, page_mask, pgidx, hash;
	uint64_t htab_mask, mask, avpn;
	ulong pgaddr;
	int i, found;
	unsigned int vsid, vsid_sh, sdr, sdr_sh, sdr_mask;
	mPTE_64_t *pp;

	vsid = (ea >> 28) + SEGR_BASE;
	vsid_sh = 7;
	vsid_mask = 0x00003FFFFFFFFF80ULL;
	asm ( "mfsdr1 %0" : "=r" (sdr) );
	sdr_sh = 18;
	sdr_mask = 0x3FF80;
	page_mask = 0x0FFFFFFF; // XXX correct?
	pgidx = (ea & page_mask) >> PAGE_SHIFT;
	avpn = (vsid << 12) | ((pgidx >> 4) & 0x0F80);;

	hash = ((vsid ^ pgidx) << vsid_sh) & vsid_mask;
	htab_mask = 0x0FFFFFFF >> (28 - (sdr & 0x1F));
	mask = (htab_mask << sdr_sh) | sdr_mask;
	pgaddr = sdr | (hash & mask);
	pp = (mPTE_64_t *)pgaddr;

	/* replace old translation */
	for( found=0, i=0; !found && i<8; i++ )
		if( pp[i].avpn == avpn )
			found=1;

	/* otherwise use a free slot */
	for( i=0; !found && i<8; i++ )
		if( !pp[i].v )
			found=1;

	/* out of slots, just evict one */
	if( !found ) {
		i = next_grab_slot + 1;
		next_grab_slot = (next_grab_slot + 1) % 8;
	}
	i--;
	{
	mPTE_64_t p = {
		// .avpn_low = avpn,
		.avpn = avpn >> 7,
		.h = 0,
		.v = 1,

		.rpn = (phys & ~0xfff) >> 12,
		.r = mode & (1 << 8) ? 1 : 0,
		.c = mode & (1 << 7) ? 1 : 0,
		.w = mode & (1 << 6) ? 1 : 0,
		.i = mode & (1 << 5) ? 1 : 0,
		.m = mode & (1 << 4) ? 1 : 0,
		.g = mode & (1 << 3) ? 1 : 0,
		.n = mode & (1 << 2) ? 1 : 0,
		.pp = mode & 3,
	};
	pp[i] = p;
	}

	asm volatile( "tlbie %0"  :: "r"(ea) );
}

static void
hash_page_32( ucell ea, ucell phys, ucell mode )
{
	static int next_grab_slot=0;
	ulong *upte, cmp, hash1;
	int i, vsid, found;
	mPTE_t *pp;

	vsid = (ea>>28) + SEGR_BASE;
	cmp = BIT(0) | (vsid << 7) | ((ea & 0x0fffffff) >> 22);

	hash1 = vsid;
	hash1 ^= (ea >> 12) & 0xffff;
	hash1 &= (get_hash_size() - 1) >> 6;

	pp = (mPTE_t*)(get_hash_base() + (hash1 << 6));
	upte = (ulong*)pp;

	/* replace old translation */
	for( found=0, i=0; !found && i<8; i++ )
		if( cmp == upte[i*2] )
			found=1;

	/* otherwise use a free slot */
	for( i=0; !found && i<8; i++ )
		if( !pp[i].v )
			found=1;

	/* out of slots, just evict one */
	if( !found ) {
		i = next_grab_slot + 1;
		next_grab_slot = (next_grab_slot + 1) % 8;
	}
	i--;
	upte[i*2] = cmp;
	upte[i*2+1] = (phys & ~0xfff) | mode;

	asm volatile( "tlbie %0"  :: "r"(ea) );
}

static int is_ppc64(void)
{
	unsigned int pvr;
	asm volatile("mfspr %0, 0x11f" : "=r" (pvr) );

	return ((pvr >= 0x330000) && (pvr < 0x70330000));
}

static void hash_page( ulong ea, ulong phys, ucell mode )
{
	if ( is_ppc64() )
		hash_page_64(ea, phys, mode);
	else
		hash_page_32(ea, phys, mode);
}

void
dsi_exception( void )
{
	ulong dar, dsisr;
	ucell mode;
	ucell phys;

	asm volatile("mfdar %0" : "=r" (dar) : );
	asm volatile("mfdsisr %0" : "=r" (dsisr) : );

	phys = ea_to_phys(dar, &mode);
	hash_page( dar, phys, mode );
}

void
isi_exception( void )
{
	ulong nip, srr1;
	ucell mode;
	ucell phys;

	asm volatile("mfsrr0 %0" : "=r" (nip) : );
	asm volatile("mfsrr1 %0" : "=r" (srr1) : );

	phys = ea_to_phys(nip, &mode);
	hash_page( nip, phys, mode );
}


/************************************************************************/
/*	init / cleanup							*/
/************************************************************************/

void
setup_mmu( ulong ramsize )
{
	ofmem_t *ofmem = OFMEM;
	ulong sdr1, sr_base, msr;
	ulong hash_base;
	ulong hash_mask = 0xffff0000;
	int i;

	memset(ofmem, 0, sizeof(ofmem_t));
	ofmem->ramsize = ramsize;

	/* SDR1: Storage Description Register 1 */

	if(is_ppc64())
		hash_mask = 0xfff00000;

	hash_base = (ramsize - 0x00100000 - HASH_SIZE) & hash_mask;
        memset((void *)hash_base, 0, HASH_SIZE);
	sdr1 = hash_base | ((HASH_SIZE-1) >> 16);
	asm volatile("mtsdr1 %0" :: "r" (sdr1) );

	/* Segment Register */

	sr_base = SEGR_USER | SEGR_BASE ;
	for( i=0; i<16; i++ ) {
		int j = i << 28;
		asm volatile("mtsrin %0,%1" :: "r" (sr_base + i), "r" (j) );
	}

	memcpy((void *)get_rom_base(), (void *)0xfff00000, 0x00100000);

	/* Enable MMU */

	asm volatile("mfmsr %0" : "=r" (msr) : );
	msr |= MSR_IR | MSR_DR;
	asm volatile("mtmsr %0" :: "r" (msr) );
}

void
ofmem_init( void )
{
	ofmem_t *ofmem = ofmem_arch_get_private();

	ofmem_map( 0, 0, get_ram_bottom(), 0 );
	ofmem_map( get_ram_top(), get_ram_top(), ofmem->ramsize - get_ram_top(), 0);
}