u-boot/arch/x86/cpu/mtrr.c

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/*
* (C) Copyright 2014 Google, Inc
*
* SPDX-License-Identifier: GPL-2.0+
*
* Memory Type Range Regsters - these are used to tell the CPU whether
* memory is cacheable and if so the cache write mode to use.
*
* These can speed up booting. See the mtrr command.
*
* Reference: Intel Architecture Software Developer's Manual, Volume 3:
* System Programming
*/
#include <common.h>
#include <asm/io.h>
#include <asm/msr.h>
#include <asm/mtrr.h>
DECLARE_GLOBAL_DATA_PTR;
/* Prepare to adjust MTRRs */
void mtrr_open(struct mtrr_state *state)
{
if (!gd->arch.has_mtrr)
return;
state->enable_cache = dcache_status();
if (state->enable_cache)
disable_caches();
state->deftype = native_read_msr(MTRR_DEF_TYPE_MSR);
wrmsrl(MTRR_DEF_TYPE_MSR, state->deftype & ~MTRR_DEF_TYPE_EN);
}
/* Clean up after adjusting MTRRs, and enable them */
void mtrr_close(struct mtrr_state *state)
{
if (!gd->arch.has_mtrr)
return;
wrmsrl(MTRR_DEF_TYPE_MSR, state->deftype | MTRR_DEF_TYPE_EN);
if (state->enable_cache)
enable_caches();
}
int mtrr_commit(bool do_caches)
{
struct mtrr_request *req = gd->arch.mtrr_req;
struct mtrr_state state;
uint64_t mask;
int i;
if (!gd->arch.has_mtrr)
return -ENOSYS;
mtrr_open(&state);
for (i = 0; i < gd->arch.mtrr_req_count; i++, req++) {
mask = ~(req->size - 1);
mask &= (1ULL << CONFIG_CPU_ADDR_BITS) - 1;
wrmsrl(MTRR_PHYS_BASE_MSR(i), req->start | req->type);
wrmsrl(MTRR_PHYS_MASK_MSR(i), mask | MTRR_PHYS_MASK_VALID);
}
/* Clear the ones that are unused */
for (; i < MTRR_COUNT; i++)
wrmsrl(MTRR_PHYS_MASK_MSR(i), 0);
mtrr_close(&state);
return 0;
}
int mtrr_add_request(int type, uint64_t start, uint64_t size)
{
struct mtrr_request *req;
uint64_t mask;
if (!gd->arch.has_mtrr)
return -ENOSYS;
if (gd->arch.mtrr_req_count == MAX_MTRR_REQUESTS)
return -ENOSPC;
req = &gd->arch.mtrr_req[gd->arch.mtrr_req_count++];
req->type = type;
req->start = start;
req->size = size;
debug("%d: type=%d, %08llx %08llx\n", gd->arch.mtrr_req_count - 1,
req->type, req->start, req->size);
mask = ~(req->size - 1);
mask &= (1ULL << CONFIG_CPU_ADDR_BITS) - 1;
mask |= MTRR_PHYS_MASK_VALID;
debug(" %016llx %016llx\n", req->start | req->type, mask);
return 0;
}