summaryrefslogtreecommitdiff
path: root/arch/i386/kernel/cpu/mtrr/centaur.c
blob: 33f00ac314ef3e1e51b4488be696ac3133b3ad28 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
#include <linux/init.h>
#include <linux/mm.h>
#include <asm/mtrr.h>
#include <asm/msr.h>
#include "mtrr.h"

static struct {
	unsigned long high;
	unsigned long low;
} centaur_mcr[8];

static u8 centaur_mcr_reserved;
static u8 centaur_mcr_type;	/* 0 for winchip, 1 for winchip2 */

/*
 *	Report boot time MCR setups 
 */

static int
centaur_get_free_region(unsigned long base, unsigned long size)
/*  [SUMMARY] Get a free MTRR.
    <base> The starting (base) address of the region.
    <size> The size (in bytes) of the region.
    [RETURNS] The index of the region on success, else -1 on error.
*/
{
	int i, max;
	mtrr_type ltype;
	unsigned long lbase;
	unsigned int lsize;

	max = num_var_ranges;
	for (i = 0; i < max; ++i) {
		if (centaur_mcr_reserved & (1 << i))
			continue;
		mtrr_if->get(i, &lbase, &lsize, &ltype);
		if (lsize == 0)
			return i;
	}
	return -ENOSPC;
}

void
mtrr_centaur_report_mcr(int mcr, u32 lo, u32 hi)
{
	centaur_mcr[mcr].low = lo;
	centaur_mcr[mcr].high = hi;
}

static void
centaur_get_mcr(unsigned int reg, unsigned long *base,
		unsigned int *size, mtrr_type * type)
{
	*base = centaur_mcr[reg].high >> PAGE_SHIFT;
	*size = -(centaur_mcr[reg].low & 0xfffff000) >> PAGE_SHIFT;
	*type = MTRR_TYPE_WRCOMB;	/*  If it is there, it is write-combining  */
	if (centaur_mcr_type == 1 && ((centaur_mcr[reg].low & 31) & 2))
		*type = MTRR_TYPE_UNCACHABLE;
	if (centaur_mcr_type == 1 && (centaur_mcr[reg].low & 31) == 25)
		*type = MTRR_TYPE_WRBACK;
	if (centaur_mcr_type == 0 && (centaur_mcr[reg].low & 31) == 31)
		*type = MTRR_TYPE_WRBACK;

}

static void centaur_set_mcr(unsigned int reg, unsigned long base,
			    unsigned long size, mtrr_type type)
{
	unsigned long low, high;

	if (size == 0) {
		/*  Disable  */
		high = low = 0;
	} else {
		high = base << PAGE_SHIFT;
		if (centaur_mcr_type == 0)
			low = -size << PAGE_SHIFT | 0x1f;	/* only support write-combining... */
		else {
			if (type == MTRR_TYPE_UNCACHABLE)
				low = -size << PAGE_SHIFT | 0x02;	/* NC */
			else
				low = -size << PAGE_SHIFT | 0x09;	/* WWO,WC */
		}
	}
	centaur_mcr[reg].high = high;
	centaur_mcr[reg].low = low;
	wrmsr(MSR_IDT_MCR0 + reg, low, high);
}

#if 0
/*
 *	Initialise the later (saner) Winchip MCR variant. In this version
 *	the BIOS can pass us the registers it has used (but not their values)
 *	and the control register is read/write
 */

static void __init
centaur_mcr1_init(void)
{
	unsigned i;
	u32 lo, hi;

	/* Unfortunately, MCR's are read-only, so there is no way to
	 * find out what the bios might have done.
	 */

	rdmsr(MSR_IDT_MCR_CTRL, lo, hi);
	if (((lo >> 17) & 7) == 1) {	/* Type 1 Winchip2 MCR */
		lo &= ~0x1C0;	/* clear key */
		lo |= 0x040;	/* set key to 1 */
		wrmsr(MSR_IDT_MCR_CTRL, lo, hi);	/* unlock MCR */
	}

	centaur_mcr_type = 1;

	/*
	 *  Clear any unconfigured MCR's.
	 */

	for (i = 0; i < 8; ++i) {
		if (centaur_mcr[i].high == 0 && centaur_mcr[i].low == 0) {
			if (!(lo & (1 << (9 + i))))
				wrmsr(MSR_IDT_MCR0 + i, 0, 0);
			else
				/*
				 *      If the BIOS set up an MCR we cannot see it
				 *      but we don't wish to obliterate it
				 */
				centaur_mcr_reserved |= (1 << i);
		}
	}
	/*  
	 *  Throw the main write-combining switch... 
	 *  However if OOSTORE is enabled then people have already done far
	 *  cleverer things and we should behave. 
	 */

	lo |= 15;		/* Write combine enables */
	wrmsr(MSR_IDT_MCR_CTRL, lo, hi);
}

/*
 *	Initialise the original winchip with read only MCR registers
 *	no used bitmask for the BIOS to pass on and write only control
 */

static void __init
centaur_mcr0_init(void)
{
	unsigned i;

	/* Unfortunately, MCR's are read-only, so there is no way to
	 * find out what the bios might have done.
	 */

	/* Clear any unconfigured MCR's.
	 * This way we are sure that the centaur_mcr array contains the actual
	 * values. The disadvantage is that any BIOS tweaks are thus undone.
	 *
	 */
	for (i = 0; i < 8; ++i) {
		if (centaur_mcr[i].high == 0 && centaur_mcr[i].low == 0)
			wrmsr(MSR_IDT_MCR0 + i, 0, 0);
	}

	wrmsr(MSR_IDT_MCR_CTRL, 0x01F0001F, 0);	/* Write only */
}

/*
 *	Initialise Winchip series MCR registers
 */

static void __init
centaur_mcr_init(void)
{
	struct set_mtrr_context ctxt;

	set_mtrr_prepare_save(&ctxt);
	set_mtrr_cache_disable(&ctxt);

	if (boot_cpu_data.x86_model == 4)
		centaur_mcr0_init();
	else if (boot_cpu_data.x86_model == 8 || boot_cpu_data.x86_model == 9)
		centaur_mcr1_init();

	set_mtrr_done(&ctxt);
}
#endif

static int centaur_validate_add_page(unsigned long base, 
				     unsigned long size, unsigned int type)
{
	/*
	 *  FIXME: Winchip2 supports uncached
	 */
	if (type != MTRR_TYPE_WRCOMB && 
	    (centaur_mcr_type == 0 || type != MTRR_TYPE_UNCACHABLE)) {
		printk(KERN_WARNING
		       "mtrr: only write-combining%s supported\n",
		       centaur_mcr_type ? " and uncacheable are"
		       : " is");
		return -EINVAL;
	}
	return 0;
}

static struct mtrr_ops centaur_mtrr_ops = {
	.vendor            = X86_VENDOR_CENTAUR,
//	.init              = centaur_mcr_init,
	.set               = centaur_set_mcr,
	.get               = centaur_get_mcr,
	.get_free_region   = centaur_get_free_region,
	.validate_add_page = centaur_validate_add_page,
	.have_wrcomb       = positive_have_wrcomb,
};

int __init centaur_init_mtrr(void)
{
	set_mtrr_ops(&centaur_mtrr_ops);
	return 0;
}

//arch_initcall(centaur_init_mtrr);