/*
 * Size memory and create the kernel page-tables on the fly while doing so.
 * Called from main(), this code should only be run by the bootstrap processor.
 */
#include "u.h"
#include "lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "io.h"

#define MEMDEBUG	0

#define PDX(va)		((((ulong)(va))>>22) & 0x03FF)
#define PTX(va)		((((ulong)(va))>>12) & 0x03FF)

enum {
	MemUPA		= 0,		/* unbacked physical address */
	MemRAM		= 1,		/* physical memory */
	MemUMB		= 2,		/* upper memory block (<16MB) */
	NMemType	= 3,

	KB		= 1024,

	MemMinMB	= 4,		/* minimum physical memory (<=4MB) */
	MemMaxMB	= 768,		/* maximum physical memory to check */

	NMemBase	= 10,
};

typedef struct {
	int	size;
	ulong	addr;
} Map;

typedef struct {
	char*	name;
	Map*	map;
	Map*	mapend;

	Lock;
} RMap;

static Map mapupa[8];
static RMap rmapupa = {
	"unallocated unbacked physical memory",
	mapupa,
	&mapupa[7],
};

static Map xmapupa[8];
static RMap xrmapupa = {
	"unbacked physical memory",
	xmapupa,
	&xmapupa[7],
};

static Map mapram[8];
static RMap rmapram = {
	"physical memory",
	mapram,
	&mapram[7],
};

static Map mapumb[64];
static RMap rmapumb = {
	"upper memory block",
	mapumb,
	&mapumb[63],
};

static Map mapumbrw[8];
static RMap rmapumbrw = {
	"UMB device memory",
	mapumbrw,
	&mapumbrw[7],
};

void
memdebug(void)
{
	Map *mp;
	ulong maxpa, maxpa1, maxpa2;

	if(MEMDEBUG == 0)
		return;

	maxpa = (nvramread(0x18)<<8)|nvramread(0x17);
	maxpa1 = (nvramread(0x31)<<8)|nvramread(0x30);
	maxpa2 = (nvramread(0x16)<<8)|nvramread(0x15);
	print("maxpa = %luX -> %luX, maxpa1 = %luX maxpa2 = %luX\n",
		maxpa, MB+maxpa*KB, maxpa1, maxpa2);

	for(mp = rmapram.map; mp->size; mp++)
		print("ram %8.8luX %8.8luX %8.8luX\n", mp->addr, (ulong)mp->size, mp->addr+mp->size);
	for(mp = rmapumb.map; mp->size; mp++)
		print("umb %8.8luX %8.8luX %8.8luX\n", mp->addr, (ulong)mp->size, mp->addr+mp->size);
	for(mp = rmapumbrw.map; mp->size; mp++)
		print("urw %8.8luX %8.8luX %8.8luX\n", mp->addr, (ulong)mp->size, mp->addr+mp->size);
	for(mp = rmapupa.map; mp->size; mp++)
		print("upa %8.8luX %8.8luX %8.8luX\n", mp->addr, (ulong)mp->size, mp->addr+mp->size);
}

void
mapfree(RMap* rmap, ulong addr, ulong size)
{
	Map *mp;
	ulong t;

	if(size == 0)
		return;

	lock(rmap);
	for(mp = rmap->map; mp->addr <= addr && mp->size; mp++)
		;

	if(mp > rmap->map && (mp-1)->addr+(mp-1)->size == addr){
		(mp-1)->size += size;
		if(addr+size == mp->addr){
			(mp-1)->size += mp->size;
			while(mp->size){
				mp++;
				(mp-1)->addr = mp->addr;
				(mp-1)->size = mp->size;
			}
		}
	}
	else{
		if(addr+size == mp->addr && mp->size){
			mp->addr -= size;
			mp->size += size;
		}
		else do{
			if(mp >= rmap->mapend){
				print("mapfree: %s: losing 0x%luX, %lud\n",
					rmap->name, addr, size);
				break;
			}
			t = mp->addr;
			mp->addr = addr;
			addr = t;
			t = mp->size;
			mp->size = size;
			mp++;
		}while(size = t);
	}
	unlock(rmap);
}

ulong
mapalloc(RMap* rmap, ulong addr, int size, int align)
{
	Map *mp;
	ulong maddr, oaddr;

	lock(rmap);
	for(mp = rmap->map; mp->size; mp++){
		maddr = mp->addr;

		if(addr){
			/*
			 * A specific address range has been given:
			 *   if the current map entry is greater then
			 *   the address is not in the map;
			 *   if the current map entry does not overlap
			 *   the beginning of the requested range then
			 *   continue on to the next map entry;
			 *   if the current map entry does not entirely
			 *   contain the requested range then the range
			 *   is not in the map.
			 */
			if(maddr > addr)
				break;
			if(mp->size < addr - maddr)	/* maddr+mp->size < addr, but no overflow */
				continue;
			if(addr - maddr > mp->size - size)	/* addr+size > maddr+mp->size, but no overflow */
				break;
			maddr = addr;
		}

		if(align > 0)
			maddr = ((maddr+align-1)/align)*align;
		if(mp->addr+mp->size-maddr < size)
			continue;

		oaddr = mp->addr;
		mp->addr = maddr+size;
		mp->size -= maddr-oaddr+size;
		if(mp->size == 0){
			do{
				mp++;
				(mp-1)->addr = mp->addr;
			}while((mp-1)->size = mp->size);
		}

		unlock(rmap);
		if(oaddr != maddr)
			mapfree(rmap, oaddr, maddr-oaddr);

		return maddr;
	}
	unlock(rmap);

	return 0;
}

static void
umbscan(void)
{
	uchar *p;

	/*
	 * Scan the Upper Memory Blocks (0xA0000->0xF0000) for pieces
	 * which aren't used; they can be used later for devices which
	 * want to allocate some virtual address space.
	 * Check for two things:
	 * 1) device BIOS ROM. This should start with a two-byte header
	 *    of 0x55 0xAA, followed by a byte giving the size of the ROM
	 *    in 512-byte chunks. These ROM's must start on a 2KB boundary.
	 * 2) device memory. This is read-write.
	 * There are some assumptions: there's VGA memory at 0xA0000 and
	 * the VGA BIOS ROM is at 0xC0000. Also, if there's no ROM signature
	 * at 0xE0000 then the whole 64KB up to 0xF0000 is theoretically up
	 * for grabs; check anyway.
	 */
	p = KADDR(0xD0000);	/*RSC: changed from 0xC0000 */
	while(p < (uchar*)KADDR(0xE0000)){
		if (p[0] == 0x55 && p[1] == 0xAA) {
			/* Skip p[2] chunks of 512 bytes.  Test for 0x55 AA before
			     poking obtrusively, or else the Thinkpad X20 dies when
			     setting up the cardbus (PB) */
			p += p[2] * 512;
			continue;
		}

		p[0] = 0xCC;
		p[2*KB-1] = 0xCC;
		if(p[0] != 0xCC || p[2*KB-1] != 0xCC){
			p[0] = 0x55;
			p[1] = 0xAA;
			p[2] = 4;
			if(p[0] == 0x55 && p[1] == 0xAA){
				p += p[2]*512;
				continue;
			}
			if(p[0] == 0xFF && p[1] == 0xFF)
				mapfree(&rmapumb, PADDR(p), 2*KB);
		}
		else
			mapfree(&rmapumbrw, PADDR(p), 2*KB);
		p += 2*KB;
	}

	p = KADDR(0xE0000);
	if(p[0] != 0x55 || p[1] != 0xAA){
		p[0] = 0xCC;
		p[64*KB-1] = 0xCC;
		if(p[0] != 0xCC && p[64*KB-1] != 0xCC)
			mapfree(&rmapumb, PADDR(p), 64*KB);
	}
}


void
meminit(ulong)
{
	/* A hack to initialize unbacked physical memory.  It's assumed PCI space is assigned by 
	     the BIOS in the 0xF0000000 range and 9load never needs more than 0x2000... to run. These
	     values leave ample space for memory allocations for uninitialized PCI cards (e.g. cardbus 
	     cards).  (pb) */
	ulong maxmem = 0x40000000;

	umbscan();
	mapfree(&rmapupa, maxmem, 0x00000000-maxmem);
	memdebug();
}

ulong
umbmalloc(ulong addr, int size, int align)
{
	ulong a;

	if(a = mapalloc(&rmapumb, addr, size, align))
		return (ulong)KADDR(a);

	return 0;
}

void
umbfree(ulong addr, int size)
{
	mapfree(&rmapumb, PADDR(addr), size);
}

ulong
umbrwmalloc(ulong addr, int size, int align)
{
	ulong a;
	uchar *p;

	if(a = mapalloc(&rmapumbrw, addr, size, align))
		return(ulong)KADDR(a);

	/*
	 * Perhaps the memory wasn't visible before
	 * the interface is initialised, so try again.
	 */
	if((a = umbmalloc(addr, size, align)) == 0)
		return 0;
	p = (uchar*)a;
	p[0] = 0xCC;
	p[size-1] = 0xCC;
	if(p[0] == 0xCC && p[size-1] == 0xCC)
		return a;
	umbfree(a, size);

	return 0;
}

void
umbrwfree(ulong addr, int size)
{
	mapfree(&rmapumbrw, PADDR(addr), size);
}

ulong*
mmuwalk(ulong* pdb, ulong va, int level, int create)
{
	ulong pa, *table;

	/*
	 * Walk the page-table pointed to by pdb and return a pointer
	 * to the entry for virtual address va at the requested level.
	 * If the entry is invalid and create isn't requested then bail
	 * out early. Otherwise, for the 2nd level walk, allocate a new
	 * page-table page and register it in the 1st level.
	 */
	table = &pdb[PDX(va)];
	if(!(*table & PTEVALID) && create == 0)
		return 0;

	switch(level){

	default:
		return 0;

	case 1:
		return table;

	case 2:
		if(*table & PTESIZE)
			panic("mmuwalk2: va %#p entry %#p ", va, *table);
		if(!(*table & PTEVALID)){
			pa = PADDR(ialloc(BY2PG, BY2PG));
			*table = pa|PTEWRITE|PTEVALID;
		}
		table = KADDR(PPN(*table));

		return &table[PTX(va)];
	}
}

static Lock mmukmaplock;

ulong
mmukmap(ulong pa, ulong va, int size)
{
	ulong pae, *table, *pdb, pgsz, *pte, x;
	int pse, sync;
	extern int cpuidax, cpuiddx;

	pdb = KADDR(getcr3());
	if((cpuiddx & 0x08) && (getcr4() & 0x10))
		pse = 1;
	else
		pse = 0;
	sync = 0;

	pa = PPN(pa);
	if(va == 0)
		va = (ulong)KADDR(pa);
	else
		va = PPN(va);

	pae = pa + size;
	lock(&mmukmaplock);
	while(pa < pae){
		table = &pdb[PDX(va)];
		/*
		 * Possibly already mapped.
		 */
		if(*table & PTEVALID){
			if(*table & PTESIZE){
				/*
				 * Big page. Does it fit within?
				 * If it does, adjust pgsz so the correct end can be
				 * returned and get out.
				 * If not, adjust pgsz up to the next 4MB boundary
				 * and continue.
				 */
				x = PPN(*table);
				if(x != pa)
					panic("mmukmap1: pa %#p entry %#p",
						pa, *table);
				x += 4*MB;
				if(pae <= x){
					pa = pae;
					break;
				}
				pgsz = x - pa;
				pa += pgsz;
				va += pgsz;

				continue;
			}
			else{
				/*
				 * Little page. Walk to the entry.
				 * If the entry is valid, set pgsz and continue.
				 * If not, make it so, set pgsz, sync and continue.
				 */
				pte = mmuwalk(pdb, va, 2, 0);
				if(pte && *pte & PTEVALID){
					x = PPN(*pte);
					if(x != pa)
						panic("mmukmap2: pa %#p entry %#p",
							pa, *pte);
					pgsz = BY2PG;
					pa += pgsz;
					va += pgsz;
					sync++;

					continue;
				}
			}
		}

		/*
		 * Not mapped. Check if it can be mapped using a big page -
		 * starts on a 4MB boundary, size >= 4MB and processor can do it.
		 * If not a big page, walk the walk, talk the talk.
		 * Sync is set.
		 */
		if(pse && (pa % (4*MB)) == 0 && (pae >= pa+4*MB)){
			*table = pa|PTESIZE|PTEWRITE|PTEUNCACHED|PTEVALID;
			pgsz = 4*MB;
		}
		else{
			pte = mmuwalk(pdb, va, 2, 1);
			*pte = pa|PTEWRITE|PTEUNCACHED|PTEVALID;
			pgsz = BY2PG;
		}
		pa += pgsz;
		va += pgsz;
		sync++;
	}
	unlock(&mmukmaplock);

	/*
	 * If something was added
	 * then need to sync up.
	 */
	if(sync)
		putcr3(PADDR(pdb));

	return pa;
}

ulong
upamalloc(ulong addr, int size, int align)
{
	ulong ae, a;

	USED(align);

	if((a = mapalloc(&rmapupa, addr, size, align)) == 0){
		memdebug();
		return 0;
	}

	/*
	 * This is a travesty, but they all are.
	 */
	ae = mmukmap(a, 0, size);

	/*
	 * Should check here that it was all delivered
	 * and put it back and barf if not.
	 */
	USED(ae);

	/*
	 * Be very careful this returns a PHYSICAL address.
	 */
	return a;
}

void
upafree(ulong pa, int size)
{
	USED(pa, size);
}