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// SPDX-License-Identifier: GPL-2.0
#include <linux/init.h>
#include <linux/io.h>
#include <linux/mm.h>
#include <asm/processor-cyrix.h>
#include <asm/processor-flags.h>
#include <asm/mtrr.h>
#include <asm/msr.h>
#include "mtrr.h"
static void
cyrix_get_arr(unsigned int reg, unsigned long *base,
unsigned long *size, mtrr_type * type)
{
unsigned char arr, ccr3, rcr, shift;
unsigned long flags;
arr = CX86_ARR_BASE + (reg << 1) + reg; /* avoid multiplication by 3 */
local_irq_save(flags);
ccr3 = getCx86(CX86_CCR3);
setCx86(CX86_CCR3, (ccr3 & 0x0f) | 0x10); /* enable MAPEN */
((unsigned char *)base)[3] = getCx86(arr);
((unsigned char *)base)[2] = getCx86(arr + 1);
((unsigned char *)base)[1] = getCx86(arr + 2);
rcr = getCx86(CX86_RCR_BASE + reg);
setCx86(CX86_CCR3, ccr3); /* disable MAPEN */
local_irq_restore(flags);
shift = ((unsigned char *) base)[1] & 0x0f;
*base >>= PAGE_SHIFT;
/*
* Power of two, at least 4K on ARR0-ARR6, 256K on ARR7
* Note: shift==0xf means 4G, this is unsupported.
*/
if (shift)
*size = (reg < 7 ? 0x1UL : 0x40UL) << (shift - 1);
else
*size = 0;
/* Bit 0 is Cache Enable on ARR7, Cache Disable on ARR0-ARR6 */
if (reg < 7) {
switch (rcr) {
case 1:
*type = MTRR_TYPE_UNCACHABLE;
break;
case 8:
*type = MTRR_TYPE_WRBACK;
break;
case 9:
*type = MTRR_TYPE_WRCOMB;
break;
case 24:
default:
*type = MTRR_TYPE_WRTHROUGH;
break;
}
} else {
switch (rcr) {
case 0:
*type = MTRR_TYPE_UNCACHABLE;
break;
case 8:
*type = MTRR_TYPE_WRCOMB;
break;
case 9:
*type = MTRR_TYPE_WRBACK;
break;
case 25:
default:
*type = MTRR_TYPE_WRTHROUGH;
break;
}
}
}
/*
* cyrix_get_free_region - get a free ARR.
*
* @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
cyrix_get_free_region(unsigned long base, unsigned long size, int replace_reg)
{
unsigned long lbase, lsize;
mtrr_type ltype;
int i;
switch (replace_reg) {
case 7:
if (size < 0x40)
break;
fallthrough;
case 6:
case 5:
case 4:
return replace_reg;
case 3:
case 2:
case 1:
case 0:
return replace_reg;
}
/* If we are to set up a region >32M then look at ARR7 immediately */
if (size > 0x2000) {
cyrix_get_arr(7, &lbase, &lsize, <ype);
if (lsize == 0)
return 7;
/* Else try ARR0-ARR6 first */
} else {
for (i = 0; i < 7; i++) {
cyrix_get_arr(i, &lbase, &lsize, <ype);
if (lsize == 0)
return i;
}
/*
* ARR0-ARR6 isn't free
* try ARR7 but its size must be at least 256K
*/
cyrix_get_arr(i, &lbase, &lsize, <ype);
if ((lsize == 0) && (size >= 0x40))
return i;
}
return -ENOSPC;
}
static u32 cr4, ccr3;
static void prepare_set(void)
{
u32 cr0;
/* Save value of CR4 and clear Page Global Enable (bit 7) */
if (boot_cpu_has(X86_FEATURE_PGE)) {
cr4 = __read_cr4();
__write_cr4(cr4 & ~X86_CR4_PGE);
}
/*
* Disable and flush caches.
* Note that wbinvd flushes the TLBs as a side-effect
*/
cr0 = read_cr0() | X86_CR0_CD;
wbinvd();
write_cr0(cr0);
wbinvd();
/* Cyrix ARRs - everything else was excluded at the top */
ccr3 = getCx86(CX86_CCR3);
/* Cyrix ARRs - everything else was excluded at the top */
setCx86(CX86_CCR3, (ccr3 & 0x0f) | 0x10);
}
static void post_set(void)
{
/* Flush caches and TLBs */
wbinvd();
/* Cyrix ARRs - everything else was excluded at the top */
setCx86(CX86_CCR3, ccr3);
/* Enable caches */
write_cr0(read_cr0() & ~X86_CR0_CD);
/* Restore value of CR4 */
if (boot_cpu_has(X86_FEATURE_PGE))
__write_cr4(cr4);
}
static void cyrix_set_arr(unsigned int reg, unsigned long base,
unsigned long size, mtrr_type type)
{
unsigned char arr, arr_type, arr_size;
arr = CX86_ARR_BASE + (reg << 1) + reg; /* avoid multiplication by 3 */
/* count down from 32M (ARR0-ARR6) or from 2G (ARR7) */
if (reg >= 7)
size >>= 6;
size &= 0x7fff; /* make sure arr_size <= 14 */
for (arr_size = 0; size; arr_size++, size >>= 1)
;
if (reg < 7) {
switch (type) {
case MTRR_TYPE_UNCACHABLE:
arr_type = 1;
break;
case MTRR_TYPE_WRCOMB:
arr_type = 9;
break;
case MTRR_TYPE_WRTHROUGH:
arr_type = 24;
break;
default:
arr_type = 8;
break;
}
} else {
switch (type) {
case MTRR_TYPE_UNCACHABLE:
arr_type = 0;
break;
case MTRR_TYPE_WRCOMB:
arr_type = 8;
break;
case MTRR_TYPE_WRTHROUGH:
arr_type = 25;
break;
default:
arr_type = 9;
break;
}
}
prepare_set();
base <<= PAGE_SHIFT;
setCx86(arr + 0, ((unsigned char *)&base)[3]);
setCx86(arr + 1, ((unsigned char *)&base)[2]);
setCx86(arr + 2, (((unsigned char *)&base)[1]) | arr_size);
setCx86(CX86_RCR_BASE + reg, arr_type);
post_set();
}
const struct mtrr_ops cyrix_mtrr_ops = {
.vendor = X86_VENDOR_CYRIX,
.set = cyrix_set_arr,
.get = cyrix_get_arr,
.get_free_region = cyrix_get_free_region,
.validate_add_page = generic_validate_add_page,
.have_wrcomb = positive_have_wrcomb,
};
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