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/* SPDX-License-Identifier: GPL-2.0-only */
#include <stdint.h>
#include <string.h>
#include <device/pci_ops.h>
#include <device/pci_def.h>
#include "gm45.h"
void init_iommu()
{
/* FIXME: proper test? */
int me_active = pci_read_config8(PCI_DEV(0, 3, 0), PCI_CLASS_REVISION) != 0xff;
int stepping = pci_read_config8(PCI_DEV(0, 0, 0), PCI_CLASS_REVISION);
mchbar_write32(0x28, IOMMU_BASE1 | 1); /* HDA @ 0:1b.0 */
if (stepping != STEPPING_B2) {
/* The official workaround is to run SMM every 64ms.
The only winning move is not to play. */
mchbar_write32(0x18, IOMMU_BASE2 | 1); /* IGD @ 0:2.0-1 */
} else {
/* write-once, so lock it down */
mchbar_write32(0x18, 0); /* disable IOMMU for IGD @ 0:2.0-1 */
}
if (me_active) {
mchbar_write32(0x10, IOMMU_BASE3 | 1); /* ME @ 0:3.0-3 */
} else {
mchbar_write32(0x10, 0); /* disable IOMMU for ME */
}
mchbar_write32(0x20, IOMMU_BASE4 | 1); /* all other DMA sources */
/* clear GTT */
u16 gtt = pci_read_config16(PCI_DEV(0, 0, 0), D0F0_GGC);
if (gtt & 0x400) { /* VT mode */
const pci_devfn_t igd = PCI_DEV(0, 2, 0);
/* setup somewhere */
pci_or_config16(igd, PCI_COMMAND, PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY);
void *bar = (void *)pci_read_config32(igd, PCI_BASE_ADDRESS_0);
/* clear GTT, 2MB is enough (and should be safe) */
memset(bar, 0, 2<<20);
/* and now disable again */
pci_and_config16(igd, PCI_COMMAND, ~(PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY));
pci_write_config32(igd, PCI_BASE_ADDRESS_0, 0);
}
if (stepping == STEPPING_B3) {
mchbar_setbits8(0xffc, 1 << 4);
const pci_devfn_t peg = PCI_DEV(0, 1, 0);
/* FIXME: proper test? */
if (pci_read_config8(peg, PCI_CLASS_REVISION) != 0xff)
pci_or_config32(peg, 0xfc, 1 << 15);
}
/* final */
mchbar_setbits8(0x94, 1 << 3);
}
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