67 lines
1.1 KiB
C
67 lines
1.1 KiB
C
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/*
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* The easiest way to deal with the need for DVMA mappings is
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* to just map the first four megabytes of RAM into DVMA space.
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* That way, dvma_mapin can just compute the DVMA alias address,
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* and dvma_mapout does nothing.
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*/
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#include <sys/param.h>
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#define DVMA_BASE 0xFF000000
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#define DVMA_MASK 0x00ffFFff
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#define DVMA_MAPLEN 0x400000 /* 4 MB */
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void
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dvma_init()
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{
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int segva, sme;
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for (segva = 0; segva < DVMA_MAPLEN; segva += NBSG) {
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sme = get_segmap(segva);
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set_segmap((DVMA_BASE | segva), sme);
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}
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}
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/* Convert a local address to a DVMA address. */
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char *
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dvma_mapin(char *addr, int len)
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{
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int va = (int)addr;
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va |= DVMA_BASE;
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return ((char *) va);
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}
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/* Convert a DVMA address to a local address. */
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char *
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dvma_mapout(char *dmabuf, int len)
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{
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if (dmabuf < (char*)DVMA_BASE)
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panic("dvma_mapout");
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return (dmabuf - DVMA_BASE);
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}
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extern char *alloc(int len);
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char *
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dvma_alloc(int len)
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{
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char *mem;
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mem = alloc(len);
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if (!mem)
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return(mem);
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return(dvma_mapin(mem, len));
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}
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extern void free(void *ptr, int len);
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void
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dvma_free(char *dvma, int len)
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{
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char *mem;
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mem = dvma_mapout(dvma, len);
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if (mem)
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free(mem, len);
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}
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