/*      $NetBSD: dvma.c,v 1.15 2009/10/21 23:12:09 snj Exp $    */
/*
* Copyright (c) 1995 Gordon W. Ross
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

/*
* The easiest way to deal with the need for DVMA mappings is to just
* map the entire megabyte of RAM where we are loaded into DVMA space.
* That way, dvma_mapin can just compute the DVMA alias address, and
* dvma_mapout does nothing.  Note that this assumes all standalone
* programs stay in the range `base_va' .. `base_va + DVMA_MAPLEN'
*/

#include <sys/param.h>
#include <sparc/sparc/asm.h>
#include <machine/pte.h>
#include <machine/ctlreg.h>

#include <lib/libsa/stand.h>
#include <sparc/stand/common/promdev.h>

#define DVMA_BASE       0xFFF00000
#define DVMA_MAPLEN     0xE0000 /* 1 MB - 128K (save MONSHORTSEG) */

static int base_va;

/*
* This module is only used on sun4, so:
*/
#define getsegmap(va)           (lduha(va, ASI_SEGMAP))
#define setsegmap(va, pmeg)     do stha(va, ASI_SEGMAP, pmeg); while(0)

void
dvma_init(void)
{
       u_int segva, dmava;
       int nseg;
       extern int start;

       /*
        * Align our address base with the DVMA segment.
        * Allocate one DVMA segment to cover the stack, which
        * grows downward from `start'.
        */
       dmava = DVMA_BASE;
       base_va = segva = (((int)&start) & -NBPSG) - NBPSG;

       /* Then double-map the DVMA addresses */
       nseg = (DVMA_MAPLEN + NBPSG - 1) >> SGSHIFT;
       while (nseg-- > 0) {
               setsegmap(dmava, getsegmap(segva));
               segva += NBPSG;
               dmava += NBPSG;
       }
}

/*
* Convert a local address to a DVMA address.
*/
char *
dvma_mapin(char *addr, size_t len)
{
       int va = (int)addr;

       va -= base_va;

#ifndef BOOTXX
       /* Make sure the address is in the DVMA map. */
       if (va < 0 || va >= DVMA_MAPLEN)
               panic("dvma_mapin: va %x (DMA base %x)", va+base_va, base_va);
#endif

       va += DVMA_BASE;

       return ((char *)va);
}

/*
* Convert a DVMA address to a local address.
*/
char *
dvma_mapout(char *addr, size_t len)
{
       int va = (int)addr;

       va -= DVMA_BASE;

#ifndef BOOTXX
       /* Make sure the address is in the DVMA map. */
       if (va < 0 || va >= DVMA_MAPLEN)
               panic("dvma_mapout: va %x (DMA base %x)", va+base_va, base_va);
#endif

       va += base_va;

       return ((char *)va);
}

char *
dvma_alloc(int len)
{
       char *mem;

       mem = alloc(len);
       if (mem == NULL)
               return (mem);
       return (dvma_mapin(mem, len));
}

void
dvma_free(char *dvma, int len)
{
       char *mem;

       mem = dvma_mapout(dvma, len);
       if (mem != NULL)
               dealloc(mem, len);
}