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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2015 Timothy Pearson <tpearson@raptorengineeringinc.com>, Raptor Engineering
* Copyright (C) 2007 Advanced Micro Devices, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc.
*/
#include <cpu/cpu.h>
#include <cpu/x86/msr.h>
#include <cpu/amd/mtrr.h>
#include <cbmem.h>
#include "ram_calc.h"
uint64_t get_uma_memory_size(uint64_t topmem)
{
uint64_t uma_size = 0;
if (IS_ENABLED(CONFIG_GFXUMA)) {
/* refer to UMA Size Consideration in 780 BDG. */
if (topmem >= 0x40000000) /* 1GB and above system memory */
uma_size = 0x10000000; /* 256M recommended UMA */
else if (topmem >= 0x20000000) /* 512M - 1023M system memory */
uma_size = 0x8000000; /* 128M recommended UMA */
else if (topmem >= 0x10000000) /* 256M - 511M system memory */
uma_size = 0x4000000; /* 64M recommended UMA */
}
return uma_size;
}
void *cbmem_top(void)
{
uint32_t topmem = rdmsr(TOP_MEM).lo;
return (void *) topmem - get_uma_memory_size(topmem);
}
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