1 /* SPDX-License-Identifier: GPL-2.0-only */
2
3 #include <stdint.h>
4
5 #include <device/pci_ops.h>
6 #include <device/pci_def.h>
7
8 #include "gm45.h"
9
init_iommu(void)10 void init_iommu(void)
11 {
12 /* FIXME: proper test? */
13 int me_active = pci_read_config8(PCI_DEV(0, 3, 0), PCI_CLASS_REVISION) != 0xff;
14 int stepping = pci_read_config8(PCI_DEV(0, 0, 0), PCI_CLASS_REVISION);
15
16 mchbar_write32(0x28, IOMMU_BASE1 | 1); /* HDA @ 0:1b.0 */
17 if (stepping != STEPPING_B2) {
18 /* The official workaround is to run SMM every 64ms.
19 The only winning move is not to play. */
20 mchbar_write32(0x18, IOMMU_BASE2 | 1); /* IGD @ 0:2.0-1 */
21 } else {
22 /* write-once, so lock it down */
23 mchbar_write32(0x18, 0); /* disable IOMMU for IGD @ 0:2.0-1 */
24 }
25 if (me_active) {
26 mchbar_write32(0x10, IOMMU_BASE3 | 1); /* ME @ 0:3.0-3 */
27 } else {
28 mchbar_write32(0x10, 0); /* disable IOMMU for ME */
29 }
30 mchbar_write32(0x20, IOMMU_BASE4 | 1); /* all other DMA sources */
31
32 if (stepping == STEPPING_B3) {
33 mchbar_setbits8(0xffc, 1 << 4);
34 const pci_devfn_t peg = PCI_DEV(0, 1, 0);
35
36 /* FIXME: proper test? */
37 if (pci_read_config8(peg, PCI_CLASS_REVISION) != 0xff)
38 pci_or_config32(peg, 0xfc, 1 << 15);
39 }
40
41 /* final */
42 mchbar_setbits8(0x94, 1 << 3);
43 }
44