summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorMikel Rychliski <mikel@mikelr.com>2021-06-11 17:48:23 -0400
committerSasha Levin <sashal@kernel.org>2021-06-30 08:47:49 -0400
commitd807b93f9bca7b1d021e89709738ecdeb7337ed6 (patch)
tree97a02db954cde0697e31f1ecddb2650eea2213b0
parent5830f2081d986440d9c0dc208ee04cb3042ffbbf (diff)
PCI: Add AMD RS690 quirk to enable 64-bit DMA
[ Upstream commit cacf994a91d3a55c0c2f853d6429cd7b86113915 ] Although the AMD RS690 chipset has 64-bit DMA support, BIOS implementations sometimes fail to configure the memory limit registers correctly. The Acer F690GVM mainboard uses this chipset and a Marvell 88E8056 NIC. The sky2 driver programs the NIC to use 64-bit DMA, which will not work: sky2 0000:02:00.0: error interrupt status=0x8 sky2 0000:02:00.0 eth0: tx timeout sky2 0000:02:00.0 eth0: transmit ring 0 .. 22 report=0 done=0 Other drivers required by this mainboard either don't support 64-bit DMA, or have it disabled using driver specific quirks. For example, the ahci driver has quirks to enable or disable 64-bit DMA depending on the BIOS version (see ahci_sb600_enable_64bit() in ahci.c). This ahci quirk matches against the SB600 SATA controller, but the real issue is almost certainly with the RS690 PCI host that it was commonly attached to. To avoid this issue in all drivers with 64-bit DMA support, fix the configuration of the PCI host. If the kernel is aware of physical memory above 4GB, but the BIOS never configured the PCI host with this information, update the registers with our values. [bhelgaas: drop PCI_DEVICE_ID_ATI_RS690 definition] Link: https://lore.kernel.org/r/20210611214823.4898-1-mikel@mikelr.com Signed-off-by: Mikel Rychliski <mikel@mikelr.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--arch/x86/pci/fixup.c44
1 files changed, 44 insertions, 0 deletions
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