x86/PCI: Disable enhanced atomics on AMD NBIO 7.7 and 7.11

Multiple users report data corruption during 64-bit DMA transfers on
systems with AMD NBIO 7.7 and 7.11 controllers.

This occurs when BIOS enables AMD "enhanced atomic operations" on PCIe Root
Ports. When enhanced atomics are enabled, any 64-bit DMA access may be
corrupted.

Disable enhanced atomics using SMN for NBIO 7.7 and 7.11 based models.

Reported-by: Mikael Etienne <mikael1022bzh@gmail.com>
Closes: https://lore.kernel.org/178789300872.392066.15963676631650361573@gmail.com/
Reported-by: Arthur Husband <artmoty@gmail.com>
Closes: https://lore.kernel.org/20260406222335.379935-1-artmoty@gmail.com/
Reported-by: Alvin Lim <alvinwylim@gmail.com>
Closes: https://lore.kernel.org/20260621100844.1224301-1-alvinwylim@gmail.com/
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
[bhelgaas: commit log, s/IOVA/DMA/ in comment]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org
Cc: David Laight <david.laight.linux@gmail.com>
Cc: John Smith <imjohnsmith4000@gmail.com>
Cc: Lennert Buytenhek <kernel@wantstofly.org>
Cc: Niklas Cassel <cassel@kernel.org>
Cc: Roland Waltersson <roland.waltersson@netinsight.net>
Link: https://patch.msgid.link/20260908190600.226485-2-mario.limonciello@amd.com

1 files changed, 99 insertions, 0 deletions

diff --git a/arch/x86/pci/fixup.c b/arch/x86/pci/fixup.c
index b301c6c8d..795d81c7a 100644
--- a/arch/x86/pci/fixup.c
+++ b/arch/x86/pci/fixup.c
@@ -886,6 +886,105 @@ static void quirk_clear_strap_no_soft_reset_dev2_f0(struct pci_dev *dev)
 	}
 }
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, 0x15b8, quirk_clear_strap_no_soft_reset_dev2_f0);
+
+/*
+ * Enhanced atomic operations can cause corruption with 64-bit DMA
+ * on these devices.
+ */
+#define RX_ENH_ATOMIC_EN		BIT(8)
+
+static const u32 nbio_7_7_pcie_smn_addrs[] = {
+	0x111401d0,
+	0x111411d0,
+	0x111421d0,
+	0x111431d0,
+	0x111441d0,
+	0x112401d0,
+	0x112411d0,
+	0x112421d0,
+	0x112431d0,
+	0x112441d0,
+	0x112451d0,
+	0x113401d0,
+	0x114401d0,
+};
+
+static const u32 nbio_7_11_pcie_smn_addrs[] = {
+	0x112401d0,
+	0x112411d0,
+	0x112421d0,
+	0x112431d0,
+	0x112441d0,
+	0x112451d0,
+	0x113401d0,
+	0x113411d0,
+	0x113421d0,
+	0x113431d0,
+	0x113441d0,
+	0x113451d0,
+};
+
+static void quirk_amd_nbio_enhanced_atomic(struct pci_dev *host_bridge,
+					   const u32 *smn_addrs,
+					   size_t nr_smn_addrs)
+{
+	bool changed = false;
+	size_t i;
+	u32 data;
+	int ret;
+
+	for (i = 0; i < nr_smn_addrs; i++) {
+		ret = amd_smn_read(0, smn_addrs[i], &data);
+		if (ret)
+			continue;
+		if (!(data & RX_ENH_ATOMIC_EN))
+			continue;
+		data = data & ~RX_ENH_ATOMIC_EN;
+		ret = amd_smn_write(0, smn_addrs[i], data);
+		if (ret)
+			continue;
+		if (changed)
+			continue;
+		ret = amd_smn_read(0, smn_addrs[i], &data);
+		if (ret)
+			continue;
+		if (data & RX_ENH_ATOMIC_EN)
+			continue;
+		changed = true;
+	}
+
+	if (changed)
+		pci_info(host_bridge, "enhanced atomics disabled\n");
+}
+
+static void quirk_amd_nbio_7_7_disable_enhanced_atomic(struct pci_dev *dev)
+{
+	quirk_amd_nbio_enhanced_atomic(dev, nbio_7_7_pcie_smn_addrs,
+				       ARRAY_SIZE(nbio_7_7_pcie_smn_addrs));
+}
+
+static void quirk_amd_nbio_7_11_disable_enhanced_atomic(struct pci_dev *dev)
+{
+	quirk_amd_nbio_enhanced_atomic(dev, nbio_7_11_pcie_smn_addrs,
+				       ARRAY_SIZE(nbio_7_11_pcie_smn_addrs));
+}
+
+/* Phoenix, Hawk Point (NBIO 7.7) */
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, 0x14E8,
+			quirk_amd_nbio_7_7_disable_enhanced_atomic);
+DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_AMD, 0x14E8,
+			quirk_amd_nbio_7_7_disable_enhanced_atomic);
+
+/* Strix, Krackan, Strix Halo (NBIO 7.11) */
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, 0x1507,
+			quirk_amd_nbio_7_11_disable_enhanced_atomic);
+DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_AMD, 0x1507,
+			quirk_amd_nbio_7_11_disable_enhanced_atomic);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, 0x1122,
+			quirk_amd_nbio_7_11_disable_enhanced_atomic);
+DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_AMD, 0x1122,
+			quirk_amd_nbio_7_11_disable_enhanced_atomic);
+
 #endif
 
 /*