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/* SPDX-License-Identifier: GPL-2.0-only */
/* Use simple device model for this file even in ramstage */
#define __SIMPLE_DEVICE__
#include <arch/romstage.h>
#include <cpu/x86/mtrr.h>
#include <cpu/x86/smm.h>
#include <device/pci_ops.h>
#include <cbmem.h>
#include <security/intel/txt/txt_platform.h>
#include <security/intel/txt/txt_register.h>
#include <types.h>
#include "haswell.h"
static uintptr_t northbridge_get_tseg_base(void)
{
return ALIGN_DOWN(pci_read_config32(HOST_BRIDGE, TSEG), 1 * MiB);
}
static uintptr_t northbridge_get_tseg_limit(void)
{
return ALIGN_DOWN(pci_read_config32(HOST_BRIDGE, BGSM), 1 * MiB);
}
union dpr_register txt_get_chipset_dpr(void)
{
return (union dpr_register) { .raw = pci_read_config32(HOST_BRIDGE, DPR) };
}
/*
* Return the topmost memory address below 4 GiB available for general
* use, from software's view of memory. Do not confuse this with TOLUD,
* which applies to the DRAM as viewed by the memory controller itself.
*/
static uintptr_t top_of_low_usable_memory(void)
{
/*
* Base of DPR is top of usable DRAM below 4 GiB. However, DPR
* isn't always enabled. Unlike most memory map registers, the
* DPR register stores top of DPR instead of its base address.
* Unless binary-patched, Haswell MRC.bin does not enable DPR.
* Top of DPR is R/O, and mirrored from TSEG base by hardware.
*/
uintptr_t tolum = northbridge_get_tseg_base();
const union dpr_register dpr = txt_get_chipset_dpr();
/* Subtract DMA Protected Range size if enabled */
if (dpr.epm)
tolum -= dpr.size * MiB;
return tolum;
}
uintptr_t cbmem_top_chipset(void)
{
return top_of_low_usable_memory();
}
void smm_region(uintptr_t *start, size_t *size)
{
*start = northbridge_get_tseg_base();
*size = northbridge_get_tseg_limit();
*size -= *start;
}
void fill_postcar_frame(struct postcar_frame *pcf)
{
/* Cache at least 8 MiB below the top of ram, and at most 8 MiB
* above top of the ram. This satisfies MTRR alignment requirement
* with different TSEG size configurations.
*/
const uintptr_t top_of_ram = ALIGN_DOWN(cbmem_top(), 8 * MiB);
postcar_frame_add_mtrr(pcf, top_of_ram - 8 * MiB, 16 * MiB, MTRR_TYPE_WRBACK);
}
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