| /* SPDX-License-Identifier: GPL-2.0-only */ |
| /* This file is part of the coreboot project. */ |
| |
| #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); |
| |
| MCHBAR32(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. */ |
| MCHBAR32(0x18) = IOMMU_BASE2 | 1; /* IGD @ 0:2.0-1 */ |
| } else { |
| /* write-once, so lock it down */ |
| MCHBAR32(0x18) = 0; /* disable IOMMU for IGD @ 0:2.0-1 */ |
| } |
| if (me_active) { |
| MCHBAR32(0x10) = IOMMU_BASE3 | 1; /* ME @ 0:3.0-3 */ |
| } else { |
| MCHBAR32(0x10) = 0; /* disable IOMMU for ME */ |
| } |
| MCHBAR32(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 */ |
| pci_devfn_t igd = PCI_DEV(0, 2, 0); |
| |
| /* setup somewhere */ |
| u8 cmd = pci_read_config8(igd, PCI_COMMAND); |
| cmd |= PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY; |
| pci_write_config8(igd, PCI_COMMAND, cmd); |
| 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 */ |
| cmd &= ~(PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY); |
| pci_write_config8(igd, PCI_COMMAND, cmd); |
| pci_write_config32(igd, PCI_BASE_ADDRESS_0, 0); |
| } |
| |
| if (stepping == STEPPING_B3) { |
| MCHBAR8(0xffc) |= 1 << 4; |
| pci_devfn_t peg = PCI_DEV(0, 1, 0); |
| /* FIXME: proper test? */ |
| if (pci_read_config8(peg, PCI_CLASS_REVISION) != 0xff) { |
| int val = pci_read_config32(peg, 0xfc) | (1 << 15); |
| pci_write_config32(peg, 0xfc, val); |
| } |
| } |
| |
| /* final */ |
| MCHBAR8(0x94) |= 1 << 3; |
| } |