diff options
| -rw-r--r-- | drivers/iommu/amd_iommu_init.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c index 81837b0710a9..faf10ba1ed9a 100644 --- a/drivers/iommu/amd_iommu_init.c +++ b/drivers/iommu/amd_iommu_init.c @@ -975,6 +975,38 @@ static void __init free_iommu_all(void) } /* + * Family15h Model 10h-1fh erratum 746 (IOMMU Logging May Stall Translations) + * Workaround: + * BIOS should disable L2B micellaneous clock gating by setting + * L2_L2B_CK_GATE_CONTROL[CKGateL2BMiscDisable](D0F2xF4_x90[2]) = 1b + */ +static void __init amd_iommu_erratum_746_workaround(struct amd_iommu *iommu) +{ + u32 value; + + if ((boot_cpu_data.x86 != 0x15) || + (boot_cpu_data.x86_model < 0x10) || + (boot_cpu_data.x86_model > 0x1f)) + return; + + pci_write_config_dword(iommu->dev, 0xf0, 0x90); + pci_read_config_dword(iommu->dev, 0xf4, &value); + + if (value & BIT(2)) + return; + + /* Select NB indirect register 0x90 and enable writing */ + pci_write_config_dword(iommu->dev, 0xf0, 0x90 | (1 << 8)); + + pci_write_config_dword(iommu->dev, 0xf4, value | 0x4); + pr_info("AMD-Vi: Applying erratum 746 workaround for IOMMU at %s\n", + dev_name(&iommu->dev->dev)); + + /* Clear the enable writing bit */ + pci_write_config_dword(iommu->dev, 0xf0, 0x90); +} + +/* * This function clues the initialization function for one IOMMU * together and also allocates the command buffer and programs the * hardware. It does NOT enable the IOMMU. This is done afterwards. @@ -1172,6 +1204,8 @@ static int iommu_init_pci(struct amd_iommu *iommu) iommu->stored_l2[i] = iommu_read_l2(iommu, i); } + amd_iommu_erratum_746_workaround(iommu); + return pci_enable_device(iommu->dev); } |