include/asm-sparc/vac-ops.h

   1 /* $Id: vac-ops.h,v 1.13 1998/01/30 10:59:59 jj Exp $ */
   2 #ifndef _SPARC_VAC_OPS_H
   3 #define _SPARC_VAC_OPS_H
   4
   5 /* vac-ops.h: Inline assembly routines to do operations on the Sparc
   6  *            VAC (virtual address cache) for the sun4c.
   7  *
   8  * Copyright (C) 1994, David S. Miller (davem@caip.rutgers.edu)
   9  */
  10
  11 #include <asm/sysen.h>
  12 #include <asm/contregs.h>
  13 #include <asm/asi.h>
  14
  15 /* The SUN4C models have a virtually addressed write-through
  16  * cache.
  17  *
  18  * The cache tags are directly accessible through an ASI and
  19  * each have the form:
  20  *
  21  * ------------------------------------------------------------
  22  * | MBZ | CONTEXT | WRITE | PRIV | VALID | MBZ | TagID | MBZ |
  23  * ------------------------------------------------------------
  24  *  31 25  24   22     21     20     19    18 16  15   2  1  0
  25  *
  26  * MBZ: These bits are either unused and/or reserved and should
  27  *      be written as zeroes.
  28  *
  29  * CONTEXT: Records the context to which this cache line belongs.
  30  *
  31  * WRITE: A copy of the writable bit from the mmu pte access bits.
  32  *
  33  * PRIV: A copy of the privileged bit from the pte access bits.
  34  *
  35  * VALID: If set, this line is valid, else invalid.
  36  *
  37  * TagID: Fourteen bits of tag ID.
  38  *
  39  * Every virtual address is seen by the cache like this:
  40  *
  41  * ----------------------------------------
  42  * |  RESV  | TagID | LINE | BYTE-in-LINE |
  43  * ----------------------------------------
  44  *  31    30 29   16 15   4 3            0
  45  *
  46  * RESV: Unused/reserved.
  47  *
  48  * TagID: Used to match the Tag-ID in that vac tags.
  49  *
  50  * LINE: Which line within the cache
  51  *
  52  * BYTE-in-LINE: Which byte within the cache line.
  53  */
  54
  55 /* Sun4c VAC Tags */
  56 #define S4CVACTAG_CID      0x01c00000
  57 #define S4CVACTAG_W        0x00200000
  58 #define S4CVACTAG_P        0x00100000
  59 #define S4CVACTAG_V        0x00080000
  60 #define S4CVACTAG_TID      0x0000fffc
  61
  62 /* Sun4c VAC Virtual Address */
  63 /* These aren't used, why bother? (Anton) */
  64 #if 0
  65 #define S4CVACVA_TID       0x3fff0000
  66 #define S4CVACVA_LINE      0x0000fff0
  67 #define S4CVACVA_BIL       0x0000000f
  68 #endif
  69
  70 /* The indexing of cache lines creates a problem.  Because the line
  71  * field of a virtual address extends past the page offset within
  72  * the virtual address it is possible to have what are called
  73  * 'bad aliases' which will create inconsistencies.  So we must make
  74  * sure that within a context that if a physical page is mapped
  75  * more than once, that 'extra' line bits are the same.  If this is
  76  * not the case, and thus is a 'bad alias' we must turn off the
  77  * cacheable bit in the pte's of all such pages.
  78  */
  79
  80 #ifdef CONFIG_SUN4
  81 #define S4CVAC_BADBITS     0x0001e000
  82 #else
  83 #define S4CVAC_BADBITS    0x0000f000
  84 #endif
  85
  86 /* The following is true if vaddr1 and vaddr2 would cause
  87  * a 'bad alias'.
  88  */
  89 #define S4CVAC_BADALIAS(vaddr1, vaddr2) \
  90         ((((unsigned long) (vaddr1)) ^ ((unsigned long) (vaddr2))) & \
  91          (S4CVAC_BADBITS))
  92
  93 /* The following structure describes the characteristics of a sun4c
  94  * VAC as probed from the prom during boot time.
  95  */
  96 struct sun4c_vac_props {
  97         unsigned int num_bytes;     /* Size of the cache */
  98         unsigned int num_lines;     /* Number of cache lines */
  99         unsigned int do_hwflushes;  /* Hardware flushing available? */
 100         enum { VAC_NONE, VAC_WRITE_THROUGH,
 101             VAC_WRITE_BACK } type;  /* What type of VAC? */
 102         unsigned int linesize;      /* Size of each line in bytes */
 103         unsigned int log2lsize;     /* log2(linesize) */
 104         unsigned int on;            /* VAC is enabled */
 105 };
 106
 107 extern struct sun4c_vac_props sun4c_vacinfo;
 108
 109 /* sun4c_enable_vac() enables the sun4c virtual address cache. */
 110 static inline void sun4c_enable_vac(void)
 111 {
 112         __asm__ __volatile__("lduba [%0] %1, %%g1\n\t"
 113                              "or    %%g1, %2, %%g1\n\t"
 114                              "stba  %%g1, [%0] %1\n\t"
 115                              : /* no outputs */
 116                              : "r" ((unsigned int) AC_SENABLE),
 117                              "i" (ASI_CONTROL), "i" (SENABLE_CACHE)
 118                              : "g1", "memory");
 119         sun4c_vacinfo.on = 1;
 120 }
 121
 122 /* sun4c_disable_vac() disables the virtual address cache. */
 123 static inline void sun4c_disable_vac(void)
 124 {
 125         __asm__ __volatile__("lduba [%0] %1, %%g1\n\t"
 126                              "andn  %%g1, %2, %%g1\n\t"
 127                              "stba  %%g1, [%0] %1\n\t"
 128                              : /* no outputs */
 129                              : "r" ((unsigned int) AC_SENABLE),
 130                              "i" (ASI_CONTROL), "i" (SENABLE_CACHE)
 131                              : "g1", "memory");
 132         sun4c_vacinfo.on = 0;
 133 }
 134
 135 #endif /* !(_SPARC_VAC_OPS_H) */