MMU.c

#include "MMU.h"



void mmuTlbFlush(ArmMmu* mmu){

	UInt8 i, j;

	for(i = 0; i < MMU_TLB_BUCKET_NUM; i++){
		for(j = 0; j < MMU_TLB_BUCKET_SIZE; j++) mmu->tlb[i][j].sz = 0;
		mmu->replPos[i] = 0;
		mmu->readPos[i] = 0;
	}
}


void mmuInit(ArmMmu* mmu, ArmMmuReadF readF, void* userData){

	__mem_zero(mmu, sizeof(ArmMmu));
	mmu->readF = readF;
	mmu->userData = userData;
	mmu->transTablPA = MMU_DISABLED_TTP;
	mmu->domainCfg = 0;
	mmuTlbFlush(mmu);
}

void muDeinit(_UNUSED_ ArmMmu* mmu){

	//nothing here
}

static _INLINE_ UInt8 mmuPrvHashAddr(UInt32 addr){	//addresses are granular on 1K

	addr >>= 10;

	addr = addr ^ (addr >> 5) ^ (addr >> 10);

	return addr % MMU_TLB_BUCKET_NUM;
}

Boolean mmuTranslate(ArmMmu* mmu, UInt32 adr, Boolean priviledged, Boolean write, UInt32* paP, UInt8* fsrP){

	UInt32 va, pa = 0, sz, t;
	UInt8 i, j, dom, ap = 0;
	Boolean section = false, coarse = true, pxa_tex_page = false;
	UInt8 bucket;

	//handle the 'MMU off' case

	if(mmu->transTablPA == MMU_DISABLED_TTP){
		va = pa = 0;
		goto calc;
	}

	//check the TLB
	if(MMU_TLB_BUCKET_SIZE && MMU_TLB_BUCKET_NUM){

		bucket = mmuPrvHashAddr(adr);

		for(j = 0, i = mmu->readPos[bucket]; j < MMU_TLB_BUCKET_SIZE; j++, i--){

			if(i == 0xFF) i = MMU_TLB_BUCKET_SIZE - 1;

			va = mmu->tlb[bucket][i].va;
			sz = mmu->tlb[bucket][i].sz;

			if(va <= adr && va + sz > adr){

				pa = mmu->tlb[bucket][i].pa;
				ap = mmu->tlb[bucket][i].ap;
				dom = mmu->tlb[bucket][i].domain;
				mmu->readPos[bucket] = i;

				goto check;
			}
		}
	}

	//read first level table

	if(mmu->transTablPA & 3){
		*fsrP = 0x01;	//alignment fault
		return false;
	}

	if(!mmu->readF(mmu->userData, &t, mmu->transTablPA + ((adr & 0xFFF00000) >> 18))){

		*fsrP = 0x0C;	//translation external abort first level
		return false;
	}

	dom = (t >> 5) & 0x0F;
	switch(t & 3){

		case 0:	//fault

			*fsrP = 0x5;	//section translation fault
			return false;

		case 1:	//coarse pagetable

			t &= 0xFFFFFC00UL;
			t += (adr & 0x000FF000UL) >> 10;
			break;

		case 2:	//1MB section

			pa = t & 0xFFF00000UL;
			va = adr & 0xFFF00000UL;
			sz = 1UL << 20;
			ap = (t >> 10) & 3;
			section = true;
			goto translated;

		case 3:	//fine page table

			coarse = false;
			t &= 0xFFFFF000UL;
			t += (adr & 0x000FFC00UL) >> 8;
			break;
	}


	//read second level table

	if(!mmu->readF(mmu->userData, &t, t)){
		*fsrP = 0x0E | (dom << 4);	//translation external abort second level
		return false;
	}

	switch(t & 3){

		case 0:	//fault

			*fsrP = 0x07 | (dom << 4);	//page translation fault
			return false;

		case 1:	//64K mapping

			pa = t & 0xFFFF0000UL;
			va = adr & 0xFFFF0000UL;
			sz = 65536UL;
			ap = (adr >> 14) & 3;		//in "ap" store which AP we need [of the 4]
			break;

		case 2:	//4K mapping (1K effective thenks to having 4 AP fields)

page_size_4k:
			pa = t & 0xFFFFF000UL;
			va = adr & 0xFFFFF000UL;
			sz = 4096;
			ap = (adr >> 10) & 3;		//in "ap" store which AP we need [of the 4]
			break;

		case 3:	//1K mapping

			if(coarse){

				pxa_tex_page = true;
				goto page_size_4k;
			}

			pa = t & 0xFFFFFC00UL;
			va = adr & 0xFFFFFC00UL;
			ap = (t >> 4) & 3;		//in "ap" store the actual AP [and skip quarter-page resolution later using the goto]
			sz = 1024;
			goto translated;
	}


	//handle 4 AP sections

	i = (t >> 4) & 0xFF;
	if(pxa_tex_page || ((i & 0x0F) == (i >> 4) && (i & 0x03) == ((i >> 2) & 0x03))){	//if all domains are the same, add the whole thing

		ap = (t >> 4) & 3;
	}
	else{	//take the quarter that is the one we need

		err_str("quarter page found!\r\n");
		ap = (t >> (4 + 2 * ap)) & 3;
		sz /= 4;
		pa += ((UInt32)ap) * sz;
		va += ((UInt32)ap) * sz;
	}


translated:

	//insert tlb entry
	if(MMU_TLB_BUCKET_NUM && MMU_TLB_BUCKET_SIZE){

		mmu->tlb[bucket][mmu->replPos[bucket]].pa = pa;
		mmu->tlb[bucket][mmu->replPos[bucket]].sz = sz;
		mmu->tlb[bucket][mmu->replPos[bucket]].va = va;
		mmu->tlb[bucket][mmu->replPos[bucket]].ap = ap;
		mmu->tlb[bucket][mmu->replPos[bucket]].domain = dom;
		mmu->readPos[bucket] = mmu->replPos[bucket];
		if(++mmu->replPos[bucket] == MMU_TLB_BUCKET_SIZE) mmu->replPos[bucket] = 0;
	}

check:

	//check domain permissions

	switch((mmu->domainCfg >> (dom * 2)) & 3){

		case 0:	//NO ACCESS:
		case 2:	//RESERVED: unpredictable	(treat as no access)

			*fsrP = (section ? 0x08 : 0xB) | (dom << 4);	//section or page domain fault
			return false;


		case 1:	//CLIENT: check permissions

			break;


		case 3:	//MANAGER: allow all access

			goto calc;

	}

	//check permissions

	switch(ap){

		case 0:

			if(write || (!mmu->R && (!priviledged || !mmu->S))) break;
			goto calc;

		case 1:

			if(!priviledged) break;
			goto calc;

		case 2:

			if(!priviledged && write) break;
			goto calc;

		case 3:

			//all is good, allow access!
			goto calc;
	}

//perm_err:

	*fsrP = (section ? 0x0D : 0x0F) | (dom << 4);		//section or subpage permission fault
	return false;

calc:

	*paP = adr - va + pa;
	return true;
}

UInt32 mmuGetTTP(ArmMmu* mmu){

	return mmu->transTablPA;
}

void mmuSetTTP(ArmMmu* mmu, UInt32 ttp){

	UInt8 i;

	mmuTlbFlush(mmu);
	for(i = 0; i < MMU_TLB_BUCKET_NUM; i++){

		mmu->replPos[i] = 0;
		mmu->readPos[i] = 0;
	}
	mmu->transTablPA = ttp;
}

void mmuSetS(ArmMmu* mmu, Boolean on){

	mmu->S = on;
}

void mmuSetR(ArmMmu* mmu, Boolean on){

	mmu->R = on;
}

Boolean mmuGetS(ArmMmu* mmu){

	return mmu->S;
}

Boolean mmuGetR(ArmMmu* mmu){

	return mmu->R;
}

UInt32 mmuGetDomainCfg(ArmMmu* mmu){

	return mmu->domainCfg;
}

void mmuSetDomainCfg(ArmMmu* mmu, UInt32 val){

	mmu->domainCfg = val;
}

///////////////////////////  debugging helpers  ///////////////////////////



UInt32 mmuDR(ArmMmu* mmu, UInt32 addr){

	UInt32 t = 0;

	if(!mmu->readF(mmu->userData, &t, addr)) t = 0xFFFFFFF0UL;

	return t;
}

#if 0
static void mmuDumpUpdate(UInt32 va, UInt32 pa, UInt32 len, UInt8 dom, UInt8 ap, Boolean c, Boolean b, Boolean valid){

	UInt32 va_end;;

	static Boolean wasValid = false;
	static UInt8 wasDom = 0;
	static UInt8 wasAp = 0;
	static Boolean wasB = 0;
	static Boolean wasC = 0;
	static UInt32 startVa = 0;
	static UInt32 startPa = 0;
	static UInt32 expectPa = 0;


	va_end = (va || len) ? va - 1 : 0xFFFFFFFFUL;

	if(!wasValid && !valid) return;	//no need to bother...

	if(valid != wasValid || dom != wasDom || ap != wasAp || c != wasC || b != wasB || expectPa != pa){	//not a continuation of what we've been at...

		if(wasValid){


			err_str("0x");
			err_hex(startVa);
			err_str("-0x");
			err_hex(va_end);
			err_str(" -> 0x");
			err_hex(startPa);
			err_str("-0x");
			err_hex(startPa + (va_end - startVa));
			err_str(" dom");
			err_dec(wasDom);
			err_str(" ap");
			err_dec(wasAp);
			err_str(" ");
			err_str(wasC ? "c" : " ");
			err_str(wasB ? "b" : " ");
			err_str("\r\n");
		}

		wasValid = valid;
		if(valid){	//start of a new range

			wasDom = dom;
			wasAp = ap;
			wasC = c;
			wasB = b;
			startVa = va;
			startPa = pa;
			expectPa = pa + len;
		}
	}
	else{	//continuation of what we've been up to...

		expectPa += len;
	}
}

static void mmuDump(ArmMmu* mmu){

	UInt32 i, j, t, sla, va, psz;
	UInt8 dom;
	Boolean coarse = false;

	for(i = 0; i < 0x1000; i++){

		t = mmuDR(mmu, mmu->transTablPA + (i << 2));
		va = i << 20;
		dom = (t >> 5) & 0x0F;
		switch(t & 3){

			case 0:		//done
				mmuDumpUpdate(va, 0, 1UL << 20, 0, 0, false, false, false);
				continue;

			case 1:		//coarse page table
				coarse = true;
				t &= 0xFFFFFC00UL;
				break;

			case 2:		//section
				mmuDumpUpdate(va, t & 0xFFF00000UL, 1UL << 20, dom, (t >> 10) & 3, !!(t & 8), !!(t & 4), true);
				continue;

			case 3:		//fine page table
				t &= 0xFFFFF000UL;
				break;
		}

		sla = t;
		psz = coarse ? 4096 : 1024;
		for(j = 0; j < ((1UL << 20) / psz); j++){
			t = mmuDR(mmu, sla + (j << 2));
			va = (i << 20) + (j * psz);
			switch(t & 3){

				case 0:		//invalid
					mmuDumpUpdate(va, 0, psz, 0, 0, false, false, false);
					break;

				case 1:		//large 64k page
					mmuDumpUpdate(va + 0 * 16384UL, (t & 0xFFFF0000UL) + 0 * 16384UL, 16384, dom, (t >>  4) & 3, !!(t & 8), !!(t & 4), true);
					mmuDumpUpdate(va + 1 * 16384UL, (t & 0xFFFF0000UL) + 1 * 16384UL, 16384, dom, (t >>  6) & 3, !!(t & 8), !!(t & 4), true);
					mmuDumpUpdate(va + 2 * 16384UL, (t & 0xFFFF0000UL) + 2 * 16384UL, 16384, dom, (t >>  8) & 3, !!(t & 8), !!(t & 4), true);
					mmuDumpUpdate(va + 3 * 16384UL, (t & 0xFFFF0000UL) + 3 * 16384UL, 16384, dom, (t >> 10) & 3, !!(t & 8), !!(t & 4), true);
					j += coarse ? 15 : 63;
					break;

				case 2:		//small 4k page
					mmuDumpUpdate(va + 0 * 1024, (t & 0xFFFFF000UL) + 0 * 1024, 1024, dom, (t >>  4) & 3, !!(t & 8), !!(t & 4), true);
					mmuDumpUpdate(va + 1 * 1024, (t & 0xFFFFF000UL) + 1 * 1024, 1024, dom, (t >>  6) & 3, !!(t & 8), !!(t & 4), true);
					mmuDumpUpdate(va + 2 * 1024, (t & 0xFFFFF000UL) + 2 * 1024, 1024, dom, (t >>  8) & 3, !!(t & 8), !!(t & 4), true);
					mmuDumpUpdate(va + 3 * 1024, (t & 0xFFFFF000UL) + 3 * 1024, 1024, dom, (t >> 10) & 3, !!(t & 8), !!(t & 4), true);
					if(!coarse) j += 3;
					break;

				case 3:		//tiny 1k page or TEX page on pxa
					if(coarse){

						mmuDumpUpdate(va, t & 0xFFFFF000UL, 4096, dom, (t >> 4) & 3, !!(t & 8), !!(t & 4), true);
					}
					else{

						mmuDumpUpdate(va, t & 0xFFFFFC00UL, 1024, dom, (t >> 4) & 3, !!(t & 8), !!(t & 4), true);
					}
					break;
			}
		}
	}
	mmuDumpUpdate(0, 0, 0, 0, 0, false, false, false);	//finish things off
}
#endif