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#include <cpu/p6/mtrr.h>
#include <cpu/p6/msr.h>
static inline unsigned long read_cr0(void)
{
unsigned long cr0;
asm volatile ("movl %%cr0, %0" : "=r" (cr0));
return cr0;
}
static inline void write_cr0(unsigned long cr0)
{
asm volatile ("movl %0, %%cr0" : : "r" (cr0));
}
/* the fixed and variable MTTRs are power-up with random values,
* clear them to MTRR_TYPE_UNCACHEABLE for safty.
*/
static void early_mtrr_init(void)
{
static const unsigned long mtrr_msrs[] = {
/* fixed mtrr */
0x250, 0x258, 0x259,
0x268, 0x269, 0x26A,
0x26B, 0x26C, 0x26D,
0x26E, 0x26F,
/* var mtrr */
0x200, 0x201, 0x202, 0x203,
0x204, 0x205, 0x206, 0x207,
0x208, 0x209, 0x20A, 0x20B,
0x20C, 0x20D, 0x20E, 0x20F,
/* NULL end of table */
0
};
msr_t msr;
const unsigned long *msr_addr;
unsigned long cr0;
print_debug("Disabling cache\r\n");
/* Just to be sure, take all the steps to disable the cache.
* This may not be needed, but C3's may...
* Invalidate the cache */
asm volatile ("invd");
/* Disable the cache */
cr0 = read_cr0();
cr0 |= 0x40000000;
write_cr0(cr0);
/* Disable Variable MTRRs */
msr.hi = 0x00000000;
msr.lo = 0x00000000;
wrmsr(0x2ff, msr);
/* Invalidate the cache again */
asm volatile ("invd");
print_debug("Clearing mtrr\r\n");
/* Inialize all of the relevant msrs to 0 */
msr.lo = 0;
msr.hi = 0;
for(msr_addr = mtrr_msrs; *msr_addr; msr_addr++) {
wrmsr(*msr_addr, msr);
}
/* Enable caching for 0 - 128MB using variable mtrr */
msr = rdmsr(0x200);
msr.hi &= 0xfffffff0;
msr.hi |= 0x00000000;
msr.lo &= 0x00000f00;
msr.lo |= 0x00000006;
wrmsr(0x200, msr);
msr = rdmsr(0x201);
msr.hi &= 0xfffffff0;
msr.hi |= 0x0000000f;
msr.lo &= 0x000007ff;
msr.lo |= 0xf0000800;
wrmsr(0x201, msr);
#if defined(XIP_ROM_SIZE) && defined(XIP_ROM_BASE)
print_debug("Setting XIP\r\n");
/* enable write through caching so we can do execute in place
* on the flash rom.
*/
msr.hi = 0x00000000;
msr.lo = XIP_ROM_BASE | MTRR_TYPE_WRTHROUGH;
wrmsr(0x202, msr);
msr.hi = 0x0000000f;
msr.lo = ~(XIP_ROM_SIZE - 1) | 0x800;
wrmsr(0x203, msr);
#endif
/* Set the default memory type and enable fixed and variable MTRRs
*/
/* Enable Variable MTRRs */
msr.hi = 0x00000000;
msr.lo = 0x00000800;
wrmsr(0x2ff, msr);
/* Enable the cache */
cr0 = read_cr0();
cr0 &= 0x9fffffff;
write_cr0(cr0);
print_debug("Enabled the cache\r\n");
}
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