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authorAli Saidi <alisaidi@amazon.com>2019-09-12 16:00:40 +0300
committerLorenzo Pieralisi <lorenzo.pieralisi@arm.com>2019-09-16 16:10:04 +0300
commit76e67e9e0f0f2debf9df192502a759bdd0cb4dab (patch)
treeaaa717e752e5e8073187a95f17ce1ac24b418a21 /drivers/pci
parent4a36a60c34f42f75e8b4f8cd24fcfade26111334 (diff)
downloadlinux-76e67e9e0f0f2debf9df192502a759bdd0cb4dab.tar.xz
PCI: Add ACS quirk for Amazon Annapurna Labs root ports
The Amazon's Annapurna Labs root ports don't advertise an ACS capability, but they don't allow peer-to-peer transactions and do validate bus numbers through the SMMU. Additionally, it's not possible for one RP to pass traffic to another RP. Signed-off-by: Ali Saidi <alisaidi@amazon.com> Signed-off-by: Jonathan Chocron <jonnyc@amazon.com> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Reviewed-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com> Reviewed-by: Andrew Murray <andrew.murray@arm.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/quirks.c20
1 files changed, 20 insertions, 0 deletions
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 208aacf39329..e96c03b4e494 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -4366,6 +4366,24 @@ static int pci_quirk_qcom_rp_acs(struct pci_dev *dev, u16 acs_flags)
return ret;
}
+static int pci_quirk_al_acs(struct pci_dev *dev, u16 acs_flags)
+{
+ if (pci_pcie_type(dev) != PCI_EXP_TYPE_ROOT_PORT)
+ return -ENOTTY;
+
+ /*
+ * Amazon's Annapurna Labs root ports don't include an ACS capability,
+ * but do include ACS-like functionality. The hardware doesn't support
+ * peer-to-peer transactions via the root port and each has a unique
+ * segment number.
+ *
+ * Additionally, the root ports cannot send traffic to each other.
+ */
+ acs_flags &= ~(PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF);
+
+ return acs_flags ? 0 : 1;
+}
+
/*
* Sunrise Point PCH root ports implement ACS, but unfortunately as shown in
* the datasheet (Intel 100 Series Chipset Family PCH Datasheet, Vol. 2,
@@ -4559,6 +4577,8 @@ static const struct pci_dev_acs_enabled {
{ PCI_VENDOR_ID_AMPERE, 0xE00A, pci_quirk_xgene_acs },
{ PCI_VENDOR_ID_AMPERE, 0xE00B, pci_quirk_xgene_acs },
{ PCI_VENDOR_ID_AMPERE, 0xE00C, pci_quirk_xgene_acs },
+ /* Amazon Annapurna Labs */
+ { PCI_VENDOR_ID_AMAZON_ANNAPURNA_LABS, 0x0031, pci_quirk_al_acs },
{ 0 }
};