1 #include <linux/init.h>
2 #include <linux/mm.h>
3 #include <asm/mtrr.h>
4 #include <asm/msr.h>
5 #include "mtrr.h"
6
7 static struct {
8 unsigned long high;
9 unsigned long low;
10 } centaur_mcr[8];
11
12 static u8 centaur_mcr_reserved;
13 static u8 centaur_mcr_type; /* 0 for winchip, 1 for winchip2 */
14
15 /*
16 * Report boot time MCR setups
17 */
18
19 static int
20 centaur_get_free_region(unsigned long base, unsigned long size, int replace_reg)
21 /* [SUMMARY] Get a free MTRR.
22 <base> The starting (base) address of the region.
23 <size> The size (in bytes) of the region.
24 [RETURNS] The index of the region on success, else -1 on error.
25 */
26 {
27 int i, max;
28 mtrr_type ltype;
29 unsigned long lbase, lsize;
30
31 max = num_var_ranges;
32 if (replace_reg >= 0 && replace_reg < max)
33 return replace_reg;
34 for (i = 0; i < max; ++i) {
35 if (centaur_mcr_reserved & (1 << i))
36 continue;
37 mtrr_if->get(i, &lbase, &lsize, <ype);
38 if (lsize == 0)
39 return i;
40 }
41 return -ENOSPC;
42 }
43
44 void
45 mtrr_centaur_report_mcr(int mcr, u32 lo, u32 hi)
46 {
47 centaur_mcr[mcr].low = lo;
48 centaur_mcr[mcr].high = hi;
49 }
50
51 static void
52 centaur_get_mcr(unsigned int reg, unsigned long *base,
53 unsigned long *size, mtrr_type * type)
54 {
55 *base = centaur_mcr[reg].high >> PAGE_SHIFT;
56 *size = -(centaur_mcr[reg].low & 0xfffff000) >> PAGE_SHIFT;
57 *type = MTRR_TYPE_WRCOMB; /* If it is there, it is write-combining */
58 if (centaur_mcr_type == 1 && ((centaur_mcr[reg].low & 31) & 2))
59 *type = MTRR_TYPE_UNCACHABLE;
60 if (centaur_mcr_type == 1 && (centaur_mcr[reg].low & 31) == 25)
61 *type = MTRR_TYPE_WRBACK;
62 if (centaur_mcr_type == 0 && (centaur_mcr[reg].low & 31) == 31)
63 *type = MTRR_TYPE_WRBACK;
64
65 }
66
67 static void centaur_set_mcr(unsigned int reg, unsigned long base,
68 unsigned long size, mtrr_type type)
69 {
70 unsigned long low, high;
71
72 if (size == 0) {
73 /* Disable */
74 high = low = 0;
75 } else {
76 high = base << PAGE_SHIFT;
77 if (centaur_mcr_type == 0)
78 low = -size << PAGE_SHIFT | 0x1f; /* only support write-combining... */
79 else {
80 if (type == MTRR_TYPE_UNCACHABLE)
81 low = -size << PAGE_SHIFT | 0x02; /* NC */
82 else
83 low = -size << PAGE_SHIFT | 0x09; /* WWO,WC */
84 }
85 }
86 centaur_mcr[reg].high = high;
87 centaur_mcr[reg].low = low;
88 wrmsr(MSR_IDT_MCR0 + reg, low, high);
89 }
90
91 #if 0
92 /*
93 * Initialise the later (saner) Winchip MCR variant. In this version
94 * the BIOS can pass us the registers it has used (but not their values)
95 * and the control register is read/write
96 */
97
98 static void __init
99 centaur_mcr1_init(void)
100 {
101 unsigned i;
102 u32 lo, hi;
103
104 /* Unfortunately, MCR's are read-only, so there is no way to
105 * find out what the bios might have done.
106 */
107
108 rdmsr(MSR_IDT_MCR_CTRL, lo, hi);
109 if (((lo >> 17) & 7) == 1) { /* Type 1 Winchip2 MCR */
110 lo &= ~0x1C0; /* clear key */
111 lo |= 0x040; /* set key to 1 */
112 wrmsr(MSR_IDT_MCR_CTRL, lo, hi); /* unlock MCR */
113 }
114
115 centaur_mcr_type = 1;
116
117 /*
118 * Clear any unconfigured MCR's.
119 */
120
121 for (i = 0; i < 8; ++i) {
122 if (centaur_mcr[i].high == 0 && centaur_mcr[i].low == 0) {
123 if (!(lo & (1 << (9 + i))))
124 wrmsr(MSR_IDT_MCR0 + i, 0, 0);
125 else
126 /*
127 * If the BIOS set up an MCR we cannot see it
128 * but we don't wish to obliterate it
129 */
130 centaur_mcr_reserved |= (1 << i);
131 }
132 }
133 /*
134 * Throw the main write-combining switch...
135 * However if OOSTORE is enabled then people have already done far
136 * cleverer things and we should behave.
137 */
138
139 lo |= 15; /* Write combine enables */
140 wrmsr(MSR_IDT_MCR_CTRL, lo, hi);
141 }
142
143 /*
144 * Initialise the original winchip with read only MCR registers
145 * no used bitmask for the BIOS to pass on and write only control
146 */
147
148 static void __init
149 centaur_mcr0_init(void)
150 {
151 unsigned i;
152
153 /* Unfortunately, MCR's are read-only, so there is no way to
154 * find out what the bios might have done.
155 */
156
157 /* Clear any unconfigured MCR's.
158 * This way we are sure that the centaur_mcr array contains the actual
159 * values. The disadvantage is that any BIOS tweaks are thus undone.
160 *
161 */
162 for (i = 0; i < 8; ++i) {
163 if (centaur_mcr[i].high == 0 && centaur_mcr[i].low == 0)
164 wrmsr(MSR_IDT_MCR0 + i, 0, 0);
165 }
166
167 wrmsr(MSR_IDT_MCR_CTRL, 0x01F0001F, 0); /* Write only */
168 }
169
170 /*
171 * Initialise Winchip series MCR registers
172 */
173
174 static void __init
175 centaur_mcr_init(void)
176 {
177 struct set_mtrr_context ctxt;
178
179 set_mtrr_prepare_save(&ctxt);
180 set_mtrr_cache_disable(&ctxt);
181
182 if (boot_cpu_data.x86_model == 4)
183 centaur_mcr0_init();
184 else if (boot_cpu_data.x86_model == 8 || boot_cpu_data.x86_model == 9)
185 centaur_mcr1_init();
186
187 set_mtrr_done(&ctxt);
188 }
189 #endif
190
191 static int centaur_validate_add_page(unsigned long base,
192 unsigned long size, unsigned int type)
193 {
194 /*
195 * FIXME: Winchip2 supports uncached
196 */
197 if (type != MTRR_TYPE_WRCOMB &&
198 (centaur_mcr_type == 0 || type != MTRR_TYPE_UNCACHABLE)) {
199 printk(KERN_WARNING
200 "mtrr: only write-combining%s supported\n",
201 centaur_mcr_type ? " and uncacheable are"
202 : " is");
203 return -EINVAL;
204 }
205 return 0;
206 }
207
208 static struct mtrr_ops centaur_mtrr_ops = {
209 .vendor = X86_VENDOR_CENTAUR,
210 // .init = centaur_mcr_init,
211 .set = centaur_set_mcr,
212 .get = centaur_get_mcr,
213 .get_free_region = centaur_get_free_region,
214 .validate_add_page = centaur_validate_add_page,
215 .have_wrcomb = positive_have_wrcomb,
216 };
217
218 int __init centaur_init_mtrr(void)
219 {
220 set_mtrr_ops(¢aur_mtrr_ops);
221 return 0;
222 }
223
224 //arch_initcall(centaur_init_mtrr);
225
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