/* * 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. */ #include <arch/io.h> #include <cbmem.h> #include <device/pci.h> #include <soc/pci_devs.h> #include <soc/systemagent.h> static uintptr_t dpr_region_start(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. */ uintptr_t dpr = pci_read_config32(SA_DEV_ROOT, DPR); uintptr_t tom = dpr & ~((1 << 20) - 1); /* Subtract DMA Protected Range size if enabled */ if (dpr & DPR_EPM) tom -= (dpr & DPR_SIZE_MASK) << 16; return tom; } void *cbmem_top(void) { return (void *) dpr_region_start(); }