[PATCH v6] PCI/portdev: Disable AER for Titan Ridge 4C 2018

[Atharva Tiwari <atharvatiwarilinuxdev@gmail.com>]

Disable AER for Intel Titan Ridge 4C 2018
(used in T2 iMacs, where the warnings appear)
that generate continuous pcieport warnings. such as:

pcieport 0000:00:1c.4: AER: Correctable error message received from 0000:07:00.0
pcieport 0000:07:00.0: PCIe Bus Error: severity=Correctable, type=Data Link Layer, (Receiver ID)
pcieport 0000:07:00.0:   device [8086:15ea] error status/mask=00000080/00002000
pcieport 0000:07:00.0:    [ 7] BadDLLP

macOS also disables AER for Thunderbolt devices and controllers in their drivers.

Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220651
Signed-off-by: Atharva Tiwari <atharvatiwarilinuxdev@gmail.com>

---
Changes since v5:
- Used the correct name for DMI check
- Used DECLARE_PCI_FIXUP_EARLY instead of DECLARE_PCI_FIXUP_FINAL
  to disable aer, before the aer init function
Changes since v4:
- Used lowercase hex letters
- Used DMI_BOARD_VENDOR instead of DMI_SYS_VENDOR
Chnages since v3:
- Fixed Grammer mistakes
Changes since v2:
- Transferred logic to arch/x86/pci/fixup.c to only target x86
- Added DMI quirk to only target Apple Systems
Changes since v1:
- Transferred logic to drivers/pci/quicks.c
---
---
 arch/x86/pci/fixup.c       | 12 ++++++++++++
 drivers/pci/pcie/aer.c     |  3 +++
 drivers/pci/pcie/portdrv.c |  2 +-
 include/linux/pci.h        |  1 +
 4 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/arch/x86/pci/fixup.c b/arch/x86/pci/fixup.c
index 25076a5acd96..402387e41450 100644
--- a/arch/x86/pci/fixup.c
+++ b/arch/x86/pci/fixup.c
@@ -1081,3 +1081,15 @@ static void quirk_tuxeo_rp_d3(struct pci_dev *pdev)
 }
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, 0x1502, quirk_tuxeo_rp_d3);
 #endif /* CONFIG_SUSPEND */
+
+#ifdef CONFIG_PCIEAER
+
+static void quirk_disable_aer(struct pci_dev *pdev)
+{
+	if (dmi_match(DMI_BOARD_VENDOR, "Apple Inc."))
+		pdev->no_aer = 1;
+}
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x15ea, quirk_disable_aer);
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x15eb, quirk_disable_aer);
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x15ec, quirk_disable_aer);
+#endif /* CONFIG_PCIEAER */
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index e0bcaa896803..45604564ce6f 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -389,6 +389,9 @@ void pci_aer_init(struct pci_dev *dev)
 {
 	int n;
 
+	if (dev->no_aer)
+		return;
+
 	dev->aer_cap = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
 	if (!dev->aer_cap)
 		return;
diff --git a/drivers/pci/pcie/portdrv.c b/drivers/pci/pcie/portdrv.c
index 38a41ccf79b9..ab904a224296 100644
--- a/drivers/pci/pcie/portdrv.c
+++ b/drivers/pci/pcie/portdrv.c
@@ -240,7 +240,7 @@ static int get_port_device_capability(struct pci_dev *dev)
 	if ((pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
              pci_pcie_type(dev) == PCI_EXP_TYPE_RC_EC) &&
 	    dev->aer_cap && pci_aer_available() &&
-	    (pcie_ports_native || host->native_aer))
+	    (pcie_ports_native || host->native_aer) && !dev->no_aer)
 		services |= PCIE_PORT_SERVICE_AER;
 #endif
 
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 864775651c6f..f447f86c6bdf 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -440,6 +440,7 @@ struct pci_dev {
 	unsigned int	multifunction:1;	/* Multi-function device */
 
 	unsigned int	is_busmaster:1;		/* Is busmaster */
+	unsigned int	no_aer:1;		/* May not use AER */
 	unsigned int	no_msi:1;		/* May not use MSI */
 	unsigned int	no_64bit_msi:1;		/* May only use 32-bit MSIs */
 	unsigned int	block_cfg_access:1;	/* Config space access blocked */
-- 
2.43.0