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// SPDX-License-Identifier: GPL-2.0
#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 */
/**
* centaur_get_free_region - 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.
*/
static int
centaur_get_free_region(unsigned long base, unsigned long size, int replace_reg)
{
unsigned long lbase, lsize;
mtrr_type ltype;
int i, max;
max = num_var_ranges;
if (replace_reg >= 0 && replace_reg < max)
return replace_reg;
for (i = 0; i < max; ++i) {
if (centaur_mcr_reserved & (1 << i))
continue;
mtrr_if->get(i, &lbase, &lsize, <ype);
if (lsize == 0)
return i;
}
return -ENOSPC;
}
static void
centaur_get_mcr(unsigned int reg, unsigned long *base,
unsigned long *size, mtrr_type * type)
{
*base = centaur_mcr[reg].high >> PAGE_SHIFT;
*size = -(centaur_mcr[reg].low & 0xfffff000) >> PAGE_SHIFT;
*type = MTRR_TYPE_WRCOMB; /* 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) {
/* Only support write-combining... */
low = -size << PAGE_SHIFT | 0x1f;
} 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);
}
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)) {
pr_warn("mtrr: only write-combining%s supported\n",
centaur_mcr_type ? " and uncacheable are" : " is");
return -EINVAL;
}
return 0;
}
const struct mtrr_ops centaur_mtrr_ops = {
.var_regs = 8,
.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,
};
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