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      1 /*	$NetBSD: dvma.c,v 1.15 2009/10/21 23:12:09 snj Exp $	*/
      2 /*
      3  * Copyright (c) 1995 Gordon W. Ross
      4  * All rights reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     25  */
     26 
     27 /*
     28  * The easiest way to deal with the need for DVMA mappings is to just
     29  * map the entire megabyte of RAM where we are loaded into DVMA space.
     30  * That way, dvma_mapin can just compute the DVMA alias address, and
     31  * dvma_mapout does nothing.  Note that this assumes all standalone
     32  * programs stay in the range `base_va' .. `base_va + DVMA_MAPLEN'
     33  */
     34 
     35 #include <sys/param.h>
     36 #include <sparc/sparc/asm.h>
     37 #include <machine/pte.h>
     38 #include <machine/ctlreg.h>
     39 
     40 #include <lib/libsa/stand.h>
     41 #include <sparc/stand/common/promdev.h>
     42 
     43 #define	DVMA_BASE	0xFFF00000
     44 #define DVMA_MAPLEN	0xE0000	/* 1 MB - 128K (save MONSHORTSEG) */
     45 
     46 static int base_va;
     47 
     48 /*
     49  * This module is only used on sun4, so:
     50  */
     51 #define	getsegmap(va)		(lduha(va, ASI_SEGMAP))
     52 #define	setsegmap(va, pmeg)	do stha(va, ASI_SEGMAP, pmeg); while(0)
     53 
     54 void
     55 dvma_init(void)
     56 {
     57 	u_int segva, dmava;
     58 	int nseg;
     59 	extern int start;
     60 
     61 	/*
     62 	 * Align our address base with the DVMA segment.
     63 	 * Allocate one DVMA segment to cover the stack, which
     64 	 * grows downward from `start'.
     65 	 */
     66 	dmava = DVMA_BASE;
     67 	base_va = segva = (((int)&start) & -NBPSG) - NBPSG;
     68 
     69 	/* Then double-map the DVMA addresses */
     70 	nseg = (DVMA_MAPLEN + NBPSG - 1) >> SGSHIFT;
     71 	while (nseg-- > 0) {
     72 		setsegmap(dmava, getsegmap(segva));
     73 		segva += NBPSG;
     74 		dmava += NBPSG;
     75 	}
     76 }
     77 
     78 /*
     79  * Convert a local address to a DVMA address.
     80  */
     81 char *
     82 dvma_mapin(char *addr, size_t len)
     83 {
     84 	int va = (int)addr;
     85 
     86 	va -= base_va;
     87 
     88 #ifndef BOOTXX
     89 	/* Make sure the address is in the DVMA map. */
     90 	if (va < 0 || va >= DVMA_MAPLEN)
     91 		panic("dvma_mapin: va %x (DMA base %x)", va+base_va, base_va);
     92 #endif
     93 
     94 	va += DVMA_BASE;
     95 
     96 	return ((char *)va);
     97 }
     98 
     99 /*
    100  * Convert a DVMA address to a local address.
    101  */
    102 char *
    103 dvma_mapout(char *addr, size_t len)
    104 {
    105 	int va = (int)addr;
    106 
    107 	va -= DVMA_BASE;
    108 
    109 #ifndef BOOTXX
    110 	/* Make sure the address is in the DVMA map. */
    111 	if (va < 0 || va >= DVMA_MAPLEN)
    112 		panic("dvma_mapout: va %x (DMA base %x)", va+base_va, base_va);
    113 #endif
    114 
    115 	va += base_va;
    116 
    117 	return ((char *)va);
    118 }
    119 
    120 char *
    121 dvma_alloc(int len)
    122 {
    123 	char *mem;
    124 
    125 	mem = alloc(len);
    126 	if (mem == NULL)
    127 		return (mem);
    128 	return (dvma_mapin(mem, len));
    129 }
    130 
    131 void
    132 dvma_free(char *dvma, int len)
    133 {
    134 	char *mem;
    135 
    136 	mem = dvma_mapout(dvma, len);
    137 	if (mem != NULL)
    138 		dealloc(mem, len);
    139 }
    140