1/* $Id: vac-ops.h,v 1.1.1.1 2007/08/03 18:53:36 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
65/* The indexing of cache lines creates a problem.  Because the line
66 * field of a virtual address extends past the page offset within
67 * the virtual address it is possible to have what are called
68 * 'bad aliases' which will create inconsistencies.  So we must make
69 * sure that within a context that if a physical page is mapped
70 * more than once, that 'extra' line bits are the same.  If this is
71 * not the case, and thus is a 'bad alias' we must turn off the
72 * cacheable bit in the pte's of all such pages.
73 */
74
75#ifdef CONFIG_SUN4
76#define S4CVAC_BADBITS     0x0001e000
77#else
78#define S4CVAC_BADBITS    0x0000f000
79#endif
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 */
91struct sun4c_vac_props {
92	unsigned int num_bytes;     /* Size of the cache */
93	unsigned int num_lines;     /* Number of cache lines */
94	unsigned int do_hwflushes;  /* Hardware flushing available? */
95	enum { VAC_NONE, VAC_WRITE_THROUGH,
96	    VAC_WRITE_BACK } type;  /* What type of VAC? */
97	unsigned int linesize;      /* Size of each line in bytes */
98	unsigned int log2lsize;     /* log2(linesize) */
99	unsigned int on;            /* VAC is enabled */
100};
101
102extern struct sun4c_vac_props sun4c_vacinfo;
103
104/* sun4c_enable_vac() enables the sun4c virtual address cache. */
105static inline void sun4c_enable_vac(void)
106{
107	__asm__ __volatile__("lduba [%0] %1, %%g1\n\t"
108			     "or    %%g1, %2, %%g1\n\t"
109			     "stba  %%g1, [%0] %1\n\t"
110			     : /* no outputs */
111			     : "r" ((unsigned int) AC_SENABLE),
112			     "i" (ASI_CONTROL), "i" (SENABLE_CACHE)
113			     : "g1", "memory");
114	sun4c_vacinfo.on = 1;
115}
116
117/* sun4c_disable_vac() disables the virtual address cache. */
118static inline void sun4c_disable_vac(void)
119{
120	__asm__ __volatile__("lduba [%0] %1, %%g1\n\t"
121			     "andn  %%g1, %2, %%g1\n\t"
122			     "stba  %%g1, [%0] %1\n\t"
123			     : /* no outputs */
124			     : "r" ((unsigned int) AC_SENABLE),
125			     "i" (ASI_CONTROL), "i" (SENABLE_CACHE)
126			     : "g1", "memory");
127	sun4c_vacinfo.on = 0;
128}
129
130#endif /* !(_SPARC_VAC_OPS_H) */
131