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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2014 Google 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <arch/io.h>
#include <cbmem.h>
#include <device/pci.h>
#include <broadwell/pci_devs.h>
#include <broadwell/systemagent.h>
unsigned long get_top_of_ram(void)
{
/*
* Base of DPR is top of usable DRAM below 4GiB. The register has
* 1 MiB alignment and reports the TOP of the range, the base
* must be calculated from the size in MiB in bits 11:4.
*/
u32 dpr = pci_read_config32(SA_DEV_ROOT, DPR);
u32 tom = dpr & ~((1 << 20) - 1);
/* Subtract DMA Protected Range size if enabled */
if (dpr & DPR_EPM)
tom -= (dpr & DPR_SIZE_MASK) << 16;
return (unsigned long)tom;
}
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