coreboot/src/northbridge/intel/i945/memmap.c

96 lines
2.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
// Use simple device model for this file even in ramstage
#define __SIMPLE_DEVICE__
#include <device/pci_ops.h>
#include <arch/romstage.h>
#include <cbmem.h>
#include "i945.h"
#include <console/console.h>
#include <cpu/x86/mtrr.h>
#include <cpu/x86/smm.h>
#include <program_loading.h>
#include <cpu/intel/smm_reloc.h>
#include <types.h>
/* Decodes TSEG region size to bytes. */
u32 decode_tseg_size(const u8 esmramc)
{
if (!(esmramc & 1))
return 0;
switch ((esmramc >> 1) & 3) {
case 0:
return 1 << 20;
case 1:
return 2 << 20;
case 2:
return 8 << 20;
case 3:
default:
die("Bad TSEG setting.\n");
}
}
static uintptr_t northbridge_get_tseg_base(void)
{
uintptr_t tom;
if (pci_read_config8(HOST_BRIDGE, DEVEN) & (DEVEN_D2F0 | DEVEN_D2F1))
/* IGD enabled, get top of Memory from BSM register */
tom = pci_read_config32(IGD_DEV, BSM);
else
tom = (pci_read_config8(HOST_BRIDGE, TOLUD) & 0xf7) << 24;
/* subtract TSEG size */
tom -= decode_tseg_size(pci_read_config8(HOST_BRIDGE, ESMRAMC));
return tom;
}
static size_t northbridge_get_tseg_size(void)
{
const u8 esmramc = pci_read_config8(HOST_BRIDGE, ESMRAMC);
return decode_tseg_size(esmramc);
}
/*
* Depending of UMA and TSEG configuration, TSEG might start at any
* 1 MiB alignment. As this may cause very greedy MTRR setup, push
* CBMEM top downwards to 4 MiB boundary.
*/
void *cbmem_top_chipset(void)
{
uintptr_t top_of_ram = ALIGN_DOWN(northbridge_get_tseg_base(), 4*MiB);
return (void *) top_of_ram;
}
/* Decodes used Graphics Mode Select (GMS) to kilobytes. */
u32 decode_igd_memory_size(const u32 gms)
{
static const u16 ggc2uma[] = { 0, 1, 4, 8, 16, 32, 48, 64 };
if (gms >= ARRAY_SIZE(ggc2uma))
die("Bad Graphics Mode Select (GMS) setting.\n");
return ggc2uma[gms] << 10;
}
void smm_region(uintptr_t *start, size_t *size)
{
*start = northbridge_get_tseg_base();
*size = northbridge_get_tseg_size();
}
void fill_postcar_frame(struct postcar_frame *pcf)
{
uintptr_t top_of_ram;
/* Cache 8 MiB region below the top of RAM and 2 MiB above top of
* RAM to cover both cbmem as the TSEG region.
*/
top_of_ram = (uintptr_t)cbmem_top();
postcar_frame_add_mtrr(pcf, top_of_ram - 8*MiB, 8*MiB, MTRR_TYPE_WRBACK);
postcar_frame_add_mtrr(pcf, northbridge_get_tseg_base(),
northbridge_get_tseg_size(), MTRR_TYPE_WRBACK);
}