blob: 68c92307b229362791c2ad051beb0872029193f7 [file] [log] [blame]
// Support for enabling/disabling BIOS ram shadowing.
//
// Copyright (C) 2008-2010 Kevin O'Connor <kevin@koconnor.net>
// Copyright (C) 2006 Fabrice Bellard
//
// This file may be distributed under the terms of the GNU LGPLv3 license.
#include "util.h" // memcpy
#include "pci.h" // pci_config_writeb
#include "config.h" // CONFIG_*
#include "pci_ids.h" // PCI_VENDOR_ID_INTEL
#include "pci_regs.h" // PCI_VENDOR_ID
#include "xen.h" // usingXen
// On the emulators, the bios at 0xf0000 is also at 0xffff0000
#define BIOS_SRC_OFFSET 0xfff00000
#define I440FX_PAM0 0x59
// Enable shadowing and copy bios.
static void
__make_bios_writable_intel(u16 bdf, u32 pam0)
{
// Make ram from 0xc0000-0xf0000 writable
int clear = 0;
int i;
for (i=0; i<6; i++) {
u32 pam = pam0 + 1 + i;
int reg = pci_config_readb(bdf, pam);
if (CONFIG_OPTIONROMS_DEPLOYED && (reg & 0x11) != 0x11) {
// Need to copy optionroms to work around qemu implementation
void *mem = (void*)(BUILD_ROM_START + i * 32*1024);
memcpy((void*)BUILD_BIOS_TMP_ADDR, mem, 32*1024);
pci_config_writeb(bdf, pam, 0x33);
memcpy(mem, (void*)BUILD_BIOS_TMP_ADDR, 32*1024);
clear = 1;
} else {
pci_config_writeb(bdf, pam, 0x33);
}
}
if (clear)
memset((void*)BUILD_BIOS_TMP_ADDR, 0, 32*1024);
// Make ram from 0xf0000-0x100000 writable
int reg = pci_config_readb(bdf, pam0);
pci_config_writeb(bdf, pam0, 0x30);
if (reg & 0x10)
// Ram already present.
return;
// Copy bios.
extern u8 code32flat_start[], code32flat_end[];
memcpy(code32flat_start, code32flat_start + BIOS_SRC_OFFSET
, code32flat_end - code32flat_start);
}
static void
make_bios_writable_intel(u16 bdf, u32 pam0)
{
int reg = pci_config_readb(bdf, pam0);
if (!(reg & 0x10)) {
// QEMU doesn't fully implement the piix shadow capabilities -
// if ram isn't backing the bios segment when shadowing is
// disabled, the code itself wont be in memory. So, run the
// code from the high-memory flash location.
u32 pos = (u32)__make_bios_writable_intel + BIOS_SRC_OFFSET;
void (*func)(u16 bdf, u32 pam0) = (void*)pos;
func(bdf, pam0);
return;
}
// Ram already present - just enable writes
__make_bios_writable_intel(bdf, pam0);
}
static void
make_bios_readonly_intel(u16 bdf, u32 pam0)
{
// Flush any pending writes before locking memory.
wbinvd();
// Write protect roms from 0xc0000-0xf0000
int i;
for (i=0; i<6; i++) {
u32 mem = BUILD_ROM_START + i * 32*1024;
u32 pam = pam0 + 1 + i;
if (RomEnd <= mem + 16*1024) {
if (RomEnd > mem)
pci_config_writeb(bdf, pam, 0x31);
break;
}
pci_config_writeb(bdf, pam, 0x11);
}
// Write protect 0xf0000-0x100000
pci_config_writeb(bdf, pam0, 0x10);
}
static void i440fx_bios_make_readonly(u16 bdf, void *arg)
{
make_bios_readonly_intel(bdf, I440FX_PAM0);
}
static const struct pci_device_id dram_controller_make_readonly_tbl[] = {
PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82441,
i440fx_bios_make_readonly),
PCI_DEVICE_END
};
// Make the 0xc0000-0x100000 area read/writable.
void
make_bios_writable(void)
{
if (CONFIG_COREBOOT || usingXen())
return;
dprintf(3, "enabling shadow ram\n");
// At this point, statically allocated variables can't be written,
// so do this search manually.
int bdf, max;
foreachbdf_in_bus(bdf, max, 0) {
u32 vendev = pci_config_readl(bdf, PCI_VENDOR_ID);
u16 vendor = vendev & 0xffff, device = vendev >> 16;
if (vendor == PCI_VENDOR_ID_INTEL
&& device == PCI_DEVICE_ID_INTEL_82441) {
make_bios_writable_intel(bdf, I440FX_PAM0);
return;
}
}
dprintf(1, "Unable to unlock ram - bridge not found\n");
}
// Make the BIOS code segment area (0xf0000) read-only.
void
make_bios_readonly(void)
{
if (CONFIG_COREBOOT || usingXen())
return;
dprintf(3, "locking shadow ram\n");
int bdf = pci_find_init_device(dram_controller_make_readonly_tbl, NULL);
if (bdf < 0) {
dprintf(1, "Unable to lock ram - bridge not found\n");
}
}
void
qemu_prep_reset(void)
{
if (CONFIG_COREBOOT)
return;
// QEMU doesn't map 0xc0000-0xfffff back to the original rom on a
// reset, so do that manually before invoking a hard reset.
make_bios_writable();
extern u8 code32flat_start[], code32flat_end[];
memcpy(code32flat_start, code32flat_start + BIOS_SRC_OFFSET
, code32flat_end - code32flat_start);
}