Linux 3.8-rc7
[cris-mirror.git] / arch / x86 / kernel / cpu / mtrr / centaur.c
blob316fe3e60a9764e479d4e49d01346c7921763ee8
1 #include <linux/init.h>
2 #include <linux/mm.h>
4 #include <asm/mtrr.h>
5 #include <asm/msr.h>
7 #include "mtrr.h"
9 static struct {
10 unsigned long high;
11 unsigned long low;
12 } centaur_mcr[8];
14 static u8 centaur_mcr_reserved;
15 static u8 centaur_mcr_type; /* 0 for winchip, 1 for winchip2 */
17 /**
18 * centaur_get_free_region - Get a free MTRR.
20 * @base: The starting (base) address of the region.
21 * @size: The size (in bytes) of the region.
23 * Returns: the index of the region on success, else -1 on error.
25 static int
26 centaur_get_free_region(unsigned long base, unsigned long size, int replace_reg)
28 unsigned long lbase, lsize;
29 mtrr_type ltype;
30 int i, max;
32 max = num_var_ranges;
33 if (replace_reg >= 0 && replace_reg < max)
34 return replace_reg;
36 for (i = 0; i < max; ++i) {
37 if (centaur_mcr_reserved & (1 << i))
38 continue;
39 mtrr_if->get(i, &lbase, &lsize, &ltype);
40 if (lsize == 0)
41 return i;
44 return -ENOSPC;
48 * Report boot time MCR setups
50 void mtrr_centaur_report_mcr(int mcr, u32 lo, u32 hi)
52 centaur_mcr[mcr].low = lo;
53 centaur_mcr[mcr].high = hi;
56 static void
57 centaur_get_mcr(unsigned int reg, unsigned long *base,
58 unsigned long *size, mtrr_type * type)
60 *base = centaur_mcr[reg].high >> PAGE_SHIFT;
61 *size = -(centaur_mcr[reg].low & 0xfffff000) >> PAGE_SHIFT;
62 *type = MTRR_TYPE_WRCOMB; /* write-combining */
64 if (centaur_mcr_type == 1 && ((centaur_mcr[reg].low & 31) & 2))
65 *type = MTRR_TYPE_UNCACHABLE;
66 if (centaur_mcr_type == 1 && (centaur_mcr[reg].low & 31) == 25)
67 *type = MTRR_TYPE_WRBACK;
68 if (centaur_mcr_type == 0 && (centaur_mcr[reg].low & 31) == 31)
69 *type = MTRR_TYPE_WRBACK;
72 static void
73 centaur_set_mcr(unsigned int reg, unsigned long base,
74 unsigned long size, mtrr_type type)
76 unsigned long low, high;
78 if (size == 0) {
79 /* Disable */
80 high = low = 0;
81 } else {
82 high = base << PAGE_SHIFT;
83 if (centaur_mcr_type == 0) {
84 /* Only support write-combining... */
85 low = -size << PAGE_SHIFT | 0x1f;
86 } else {
87 if (type == MTRR_TYPE_UNCACHABLE)
88 low = -size << PAGE_SHIFT | 0x02; /* NC */
89 else
90 low = -size << PAGE_SHIFT | 0x09; /* WWO, WC */
93 centaur_mcr[reg].high = high;
94 centaur_mcr[reg].low = low;
95 wrmsr(MSR_IDT_MCR0 + reg, low, high);
98 static int
99 centaur_validate_add_page(unsigned long base, unsigned long size, unsigned int type)
102 * FIXME: Winchip2 supports uncached
104 if (type != MTRR_TYPE_WRCOMB &&
105 (centaur_mcr_type == 0 || type != MTRR_TYPE_UNCACHABLE)) {
106 pr_warning("mtrr: only write-combining%s supported\n",
107 centaur_mcr_type ? " and uncacheable are" : " is");
108 return -EINVAL;
110 return 0;
113 static const struct mtrr_ops centaur_mtrr_ops = {
114 .vendor = X86_VENDOR_CENTAUR,
115 .set = centaur_set_mcr,
116 .get = centaur_get_mcr,
117 .get_free_region = centaur_get_free_region,
118 .validate_add_page = centaur_validate_add_page,
119 .have_wrcomb = positive_have_wrcomb,
122 int __init centaur_init_mtrr(void)
124 set_mtrr_ops(&centaur_mtrr_ops);
125 return 0;