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