diff mbox series

PCI: Add ACS quirk for Loongson PCIe

Message ID 20250402060354.4061578-1-chenhuacai@loongson.cn (mailing list archive)
State New
Headers show
Series PCI: Add ACS quirk for Loongson PCIe | expand

Commit Message

Huacai Chen April 2, 2025, 6:03 a.m. UTC 
Loongson PCIe Root Ports don't advertise an ACS capability, but they do
not allow peer-to-peer transactions between Root Ports. Add an ACS quirk
so each Root Port can be in a separate IOMMU group.

Cc: stable@vger.kernel.org
Signed-off-by: Xianglai Li <lixianglai@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
 drivers/pci/quirks.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
diff mbox series

Patch

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 8d610c17e0f2..d52ec85f3382 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -4995,6 +4995,18 @@  static int pci_quirk_brcm_acs(struct pci_dev *dev, u16 acs_flags)
 		PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF);
 }
 
+static int pci_quirk_loongson_acs(struct pci_dev *dev, u16 acs_flags)
+{
+	/*
+	 * Loongson PCIe Root Ports don't advertise an ACS capability, but
+	 * they do not allow peer-to-peer transactions between Root Ports.
+	 * Allow each Root Port to be in a separate IOMMU group by masking
+	 * SV/RR/CR/UF bits.
+	 */
+	return pci_acs_ctrl_enabled(acs_flags,
+		PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF);
+}
+
 /*
  * Wangxun 40G/25G/10G/1G NICs have no ACS capability, but on
  * multi-function devices, the hardware isolates the functions by
@@ -5128,6 +5140,9 @@  static const struct pci_dev_acs_enabled {
 	{ PCI_VENDOR_ID_BROADCOM, 0x1762, pci_quirk_mf_endpoint_acs },
 	{ PCI_VENDOR_ID_BROADCOM, 0x1763, pci_quirk_mf_endpoint_acs },
 	{ PCI_VENDOR_ID_BROADCOM, 0xD714, pci_quirk_brcm_acs },
+	/* Loongson PCIe Root Ports */
+	{ PCI_VENDOR_ID_LOONGSON, 0x3C09, pci_quirk_loongson_acs },
+	{ PCI_VENDOR_ID_LOONGSON, 0x3C19, pci_quirk_loongson_acs },
 	/* Amazon Annapurna Labs */
 	{ PCI_VENDOR_ID_AMAZON_ANNAPURNA_LABS, 0x0031, pci_quirk_al_acs },
 	/* Zhaoxin multi-function devices */