diff --git a/arch/x86/pci/fixup.c b/arch/x86/pci/fixup.c
index 0c67a5a94de3..76959a7d88c8 100644
--- a/arch/x86/pci/fixup.c
+++ b/arch/x86/pci/fixup.c
@@ -779,4 +779,48 @@ DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_AMD, 0x1571, pci_amd_enable_64bit_bar);
 DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_AMD, 0x15b1, pci_amd_enable_64bit_bar);
 DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_AMD, 0x1601, pci_amd_enable_64bit_bar);
 
+#define RS690_LOWER_TOP_OF_DRAM2	0x30
+#define RS690_LOWER_TOP_OF_DRAM2_VALID	0x1
+#define RS690_UPPER_TOP_OF_DRAM2	0x31
+#define RS690_HTIU_NB_INDEX		0xA8
+#define RS690_HTIU_NB_INDEX_WR_ENABLE	0x100
+#define RS690_HTIU_NB_DATA		0xAC
+
+/*
+ * Some BIOS implementations support RAM above 4GB, but do not configure the
+ * PCI host to respond to bus master accesses for these addresses. These
+ * implementations set the TOP_OF_DRAM_SLOT1 register correctly, so PCI DMA
+ * works as expected for addresses below 4GB.
+ *
+ * Reference: "AMD RS690 ASIC Family Register Reference Guide" (pg. 2-57)
+ * https://www.amd.com/system/files/TechDocs/43372_rs690_rrg_3.00o.pdf
+ */
+static void rs690_fix_64bit_dma(struct pci_dev *pdev)
+{
+	u32 val = 0;
+	phys_addr_t top_of_dram = __pa(high_memory - 1) + 1;
+
+	if (top_of_dram <= (1ULL << 32))
+		return;
+
+	pci_write_config_dword(pdev, RS690_HTIU_NB_INDEX,
+				RS690_LOWER_TOP_OF_DRAM2);
+	pci_read_config_dword(pdev, RS690_HTIU_NB_DATA, &val);
+
+	if (val)
+		return;
+
+	pci_info(pdev, "Adjusting top of DRAM to %pa for 64-bit DMA support\n", &top_of_dram);
+
+	pci_write_config_dword(pdev, RS690_HTIU_NB_INDEX,
+		RS690_UPPER_TOP_OF_DRAM2 | RS690_HTIU_NB_INDEX_WR_ENABLE);
+	pci_write_config_dword(pdev, RS690_HTIU_NB_DATA, top_of_dram >> 32);
+
+	pci_write_config_dword(pdev, RS690_HTIU_NB_INDEX,
+		RS690_LOWER_TOP_OF_DRAM2 | RS690_HTIU_NB_INDEX_WR_ENABLE);
+	pci_write_config_dword(pdev, RS690_HTIU_NB_DATA,
+		top_of_dram | RS690_LOWER_TOP_OF_DRAM2_VALID);
+}
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x7910, rs690_fix_64bit_dma);
+
 #endif