4 files changed, 36 insertions, 0 deletions

diff --git a/arch/x86/include/asm/amd_iommu_proto.h b/arch/x86/include/asm/amd_iommu_proto.h
index d2544f1d705d..cb030374b90a 100644
--- a/arch/x86/include/asm/amd_iommu_proto.h
+++ b/arch/x86/include/asm/amd_iommu_proto.h
@@ -38,4 +38,10 @@ static inline void amd_iommu_stats_init(void) { }
 
 #endif /* !CONFIG_AMD_IOMMU_STATS */
 
+static inline bool is_rd890_iommu(struct pci_dev *pdev)
+{
+        return (pdev->vendor == PCI_VENDOR_ID_ATI) &&
+               (pdev->device == PCI_DEVICE_ID_RD890_IOMMU);
+}
+
 #endif /* _ASM_X86_AMD_IOMMU_PROTO_H  */
diff --git a/arch/x86/include/asm/amd_iommu_types.h b/arch/x86/include/asm/amd_iommu_types.h
index ef2d5cd7d7e7..08616180deaf 100644
--- a/arch/x86/include/asm/amd_iommu_types.h
+++ b/arch/x86/include/asm/amd_iommu_types.h
@@ -414,6 +414,15 @@ struct amd_iommu {
 
         /* default dma_ops domain for that IOMMU */
         struct dma_ops_domain *default_dom;
+
+        /*
+         * This array is required to work around a potential BIOS bug.
+         * The BIOS may miss to restore parts of the PCI configuration
+         * space when the system resumes from S3. The result is that the
+         * IOMMU does not execute commands anymore which leads to system
+         * failure.
+         */
+        u32 cache_cfg[4];
 };
 
 /*
diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index 85e9817ead43..5a170cbbbed8 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -632,6 +632,13 @@ static void __init init_iommu_from_pci(struct amd_iommu *iommu)
         iommu->last_device = calc_devid(MMIO_GET_BUS(range),
                                         MMIO_GET_LD(range));
         iommu->evt_msi_num = MMIO_MSI_NUM(misc);
+
+        if (is_rd890_iommu(iommu->dev)) {
+                pci_read_config_dword(iommu->dev, 0xf0, &iommu->cache_cfg[0]);
+                pci_read_config_dword(iommu->dev, 0xf4, &iommu->cache_cfg[1]);
+                pci_read_config_dword(iommu->dev, 0xf8, &iommu->cache_cfg[2]);
+                pci_read_config_dword(iommu->dev, 0xfc, &iommu->cache_cfg[3]);
+        }
 }
 
 /*
@@ -1120,6 +1127,16 @@ static void iommu_init_flags(struct amd_iommu *iommu)
         iommu_feature_enable(iommu, CONTROL_COHERENT_EN);
 }
 
+static void iommu_apply_quirks(struct amd_iommu *iommu)
+{
+        if (is_rd890_iommu(iommu->dev)) {
+                pci_write_config_dword(iommu->dev, 0xf0, iommu->cache_cfg[0]);
+                pci_write_config_dword(iommu->dev, 0xf4, iommu->cache_cfg[1]);
+                pci_write_config_dword(iommu->dev, 0xf8, iommu->cache_cfg[2]);
+                pci_write_config_dword(iommu->dev, 0xfc, iommu->cache_cfg[3]);
+        }
+}
+
 /*
  * This function finally enables all IOMMUs found in the system after
  * they have been initialized
@@ -1130,6 +1147,7 @@ static void enable_iommus(void)
 
         for_each_iommu(iommu) {
                 iommu_disable(iommu);
+                iommu_apply_quirks(iommu);
                 iommu_init_flags(iommu);
                 iommu_set_device_table(iommu);
                 iommu_enable_command_buffer(iommu);
diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h
index 10d33309e9a6..570fddeb0388 100644
--- a/include/linux/pci_ids.h
+++ b/include/linux/pci_ids.h
@@ -393,6 +393,9 @@
 #define PCI_DEVICE_ID_VLSI_82C147       0x0105
 #define PCI_DEVICE_ID_VLSI_VAS96011     0x0702
 
+/* AMD RD890 Chipset */
+#define PCI_DEVICE_ID_RD890_IOMMU       0x5a23
+
 #define PCI_VENDOR_ID_ADL               0x1005
 #define PCI_DEVICE_ID_ADL_2301          0x2301