arch/sparc/include/asm/vac-ops.h

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