/*
    MMDirectMapping.c, Copyright  (c) by George Fankhauser,
    Swiss Federal Institute of Technology,
    Computer Engineering and Networks Laboratory.

    TOPSY -- A Teachable Operating System.
             Implementation of a tiny and simple
             micro kernel for teaching purposes.

    For further information, please visit http://www.tik.ee.ethz.ch/~topsy

    This software is provided under the terms of the GNU General Public Licence.

    A full copy of the GNU GPL is provided in the file COPYING found in the 
    development root of Topsy.
*/
/*
	
	File:                  $Source: /usr/drwho/vault/cvs/topsy/Topsy/Memory/mips/MMDirectMapping.c,v $
 	Author(s):             George Fankhauser
 	Affiliation:           ETH Zuerich, TIK
 	Version:               $Revision: 1.14 $
 	Creation Date:         
 	Last Date of Change:   $Date: 2000/03/31 17:50:32 $      by: $Author: gfa $
	
	
	$Log: MMDirectMapping.c,v $
	Revision 1.14  2000/03/31 17:50:32  gfa
	Merged with /Net from several term projects
	
	Revision 1.13  1999/12/13 21:48:31  ruf
	GNU General Public Licence Update
	
	Revision 1.12  1999/10/31 14:42:47  jeker
	first fixes for SimOS
	
	Revision 1.11  1999/10/27 14:20:08  jeker
	fixes in mips asm code

	Revision 1.10  1999/10/27 11:04:59  jeker
	fixes R4k R3k port

	Revision 1.9  1999/10/27 04:51:07  jeker
	*** empty log message ***

	Revision 1.8  1999/10/21 20:22:28  jeker
	first commit for the R4k support

	Revision 1.7  1999/04/08 15:29:10  jeker
	Forgot to define bootStackBottom

	Revision 1.6  1998/04/11 20:22:05  gfa
	uses longCopy

	Revision 1.5  1997/04/23 11:52:13  gfa
	beautyfied

 * Revision 1.4  1997/04/13  16:22:33  gfa
 * added user-in-kernel-at address
 *
 * Revision 1.3  1997/04/13  15:32:17  gfa
 * fixed mmAddressSpaceRange
 *
 * Revision 1.2  1997/04/06  18:48:27  gfa
 * moved to $(ARCH) directory
 *
 * Revision 1.1  1997/04/06  15:45:24  gfa
 * Initial revision
 *
 * Revision 1.9  1997/03/27  13:54:20  conrad
 * failed for vmProtect
 *
 * Revision 1.8  1997/03/16  22:15:48  gfa
 * first implementation of the low level functions
 *
 * Revision 1.7  1997/03/14  00:00:22  gfa
 * moved phy/log page macros to MemoryLayout.h
 *
 * Revision 1.6  1997/03/11  08:15:27  gfa
 * tlb setup tested and working
 *
 * Revision 1.5  1997/03/09  20:47:25  gfa
 * wrote init and address space functions
 *
 * Revision 1.4  1997/02/13  16:25:21  zitzler
 * cosmetics (now very pretty)
 *
 * Revision 1.3  1997/02/13  16:23:07  zitzler
 * cosmetics
 *
 * Revision 1.2  1997/02/13  15:43:44  conrad
 * First compilation/linking of complete environment (all modules)
 *
 * Revision 1.1  1997/02/12  16:18:30  zitzler
 * Initial revision
 *
*/

#include "MMMapping.h"
#include "Threads.h"
#include "Support.h"
#include "SupportMIPS.h"
#include "tlb.h"
#include "cpu.h"

unsigned int bootStackBottom;

Error   mmInitMemoryMapping(Address codeAddr, unsigned long int codeSize,
			    Address dataAddr, unsigned long int dataSize,
			    Address userLoadedInKernelAt)
{
    /* to simulate a directmapped memory on a paged machine we fill
     * the TLB to provide the user with 64*4k memory from 4k to (256+4)k - 1.
     * Pages from [PHYSMEM-256k, PHYSMEM] are mapped to [4, 260k].
     * Page Table Entries are set to valid and global.
     * (setting up a *real* virtual memory system is lot harder) 
     */
	Register lo, hi;
    unsigned int i;
	unsigned long int lo0, lo1;

    /* start at 0x00001000 to leave page zero invalid (nil pointer catcher) */
    hi = KUSEG_BASE+PAGESIZE;
    
    if ( getPRID() == PRID_R3k ) {
		/* R3k TLB */
		ioConsolePutString("Topsy is running on a mips R3k machine\n");
		lo = ((PHYSMEM-USERMEM+PHYS_BASE) & TLB_LO_PFN_MASK_R3k) | 
									  TLB_VALID_R3k | TLB_GLOBAL_R3k | TLB_DIRTY_R3k;
		for (i = 0; i < TLB_SIZE_R3k; i++) {
			setR3kTLBEntry(lo, hi, i); 
			hi += PAGESIZE; lo += PAGESIZE; /* yes, physical pages */
		}
	} else {
		/* R4k TLB */
		ioConsolePutString("Topsy is running on a mips R4k machine\n");
		lo = (((PHYSMEM-USERMEM+PHYS_BASE)>>TLB_LO_PFN_SHIFT_R4k) & TLB_LO_PFN_MASK_R4k) 
				| TLB_CACHED_R4k | TLB_DIRTY_R4k | TLB_VALID_R4k | TLB_GLOBAL_R4k;

		lo0 = 0 | TLB_GLOBAL_R4k;
		lo1 = lo;

		for (i = 0; i < TLB_USER_SIZE_R4k; i++) {
			setR4kTLBEntry(lo0, lo1, hi, i);
			hi += (PAGESIZE<<1);
			lo += (PAGESIZE>>6); /* yes, physical pages */
			lo0 = lo;
			lo += (PAGESIZE>>6);
			lo1 = lo;
		}

		lo1 = 0 | TLB_GLOBAL_R4k;
		setR4kTLBEntry(lo0, lo1, hi, i);    
		hi += (PAGESIZE<<2);

		lo0 = 0 | TLB_GLOBAL_R4k;
		for (i = (TLB_USER_SIZE_R4k+1); i < TLB_SIZE_R4k; i++) {
			setR4kTLBEntry(lo0, lo0, hi, i);    
		}

		/* set number of wired TLB entries */
		setR4kTLBWired(TLB_SAFE_SIZE_R4k);
	}

	/* once the mapping is done, copy user code and data */ 
	byteCopy(codeAddr, userLoadedInKernelAt, codeSize);
	byteCopy(dataAddr, (Address)((unsigned long)userLoadedInKernelAt + 
		(unsigned long)dataAddr - (unsigned long)codeAddr), dataSize);

	return MM_INITMEMORYMAPPINGOK;
}

Error mmMapPages(Page startPage, Page nOfPages, PageStatus pstat)
{
    return MM_MAPPAGESOK;
}


Error mmUnmapPages(Page startPage, Page nOfPages)
{
    return MM_UNMAPPAGESOK;
}


Error mmMovePage(Page from, Page to)
{
    /* direct mapped memory systems can only copy the page */
    byteCopy((Address)(to*LOGICALPAGESIZE), (Address)(from*LOGICALPAGESIZE), 
							    LOGICALPAGESIZE);
    zeroOut((Address)(from*LOGICALPAGESIZE), LOGICALPAGESIZE);
    return MM_MOVEPAGEOK;
} 


Error mmProtectPage(Page page, ProtectionMode pmode)
{
    /* direct mapped memory does nothing */
    return MM_PROTECTPAGEFAILED;
}


Error  mmAddressSpaceRange(AddressSpace space, Address* addressPtr,
					unsigned long int* sizePtr)
{
    if (space == KERNEL) {
    	*addressPtr = (Address)K0SEG_BASE;
	*sizePtr = (PHYSMEM-USERMEM); /* 768kB */
    }
    else if (space == USER) {
    	*addressPtr = (Address)KUSEG_BASE + PAGESIZE; /* zero page invalid */
	*sizePtr = USERMEM;           /* 256kB */
    }
    else return MM_ADDRESSSPACERANGEFAILED;
    return MM_ADDRESSSPACERANGEOK;
}