[SRU][R][PATCH 2/3] x86/PCI: Disable enhanced atomics on AMD NBIO 7.7 and 7.11

[Yo-Jung Leo Lin (AMD)]

From: Mario Limonciello <mario.limonciello at amd.com>

BugLink: https://bugs.launchpad.net/bugs/2166838

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 at gmail.com>
Closes: https://lore.kernel.org/178789300872.392066.15963676631650361573@gmail.com/
Reported-by: Arthur Husband <artmoty at gmail.com>
Closes: https://lore.kernel.org/20260406222335.379935-1-artmoty@gmail.com/
Reported-by: Alvin Lim <alvinwylim at gmail.com>
Closes: https://lore.kernel.org/20260621100844.1224301-1-alvinwylim@gmail.com/
Signed-off-by: Mario Limonciello <mario.limonciello at amd.com>
[bhelgaas: commit log, s/IOVA/DMA/ in comment]
Signed-off-by: Bjorn Helgaas <bhelgaas at google.com>
Cc: stable at vger.kernel.org
Cc: David Laight <david.laight.linux at gmail.com>
Cc: John Smith <imjohnsmith4000 at gmail.com>
Cc: Lennert Buytenhek <kernel at wantstofly.org>
Cc: Niklas Cassel <cassel at kernel.org>
Cc: Roland Waltersson <roland.waltersson at netinsight.net>
Link: https://patch.msgid.link/20260908190600.226485-2-mario.limonciello@amd.com
(cherry picked from commit 4fde448225123442c5796f54b7a4400e2d3cbaf6)
Signed-off-by: Yo-Jung Leo Lin (AMD) <Leo.Lin at amd.com>
---
 arch/x86/pci/fixup.c | 99 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)

diff --git a/arch/x86/pci/fixup.c b/arch/x86/pci/fixup.c
index b301c6c8df753..795d81c7a4de4 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
 
 /*
-- 
2.43.0