[PATCH 1/2][Bionic][SRU Artful] PCI: Set Cavium ACS capability quirk flags to assert RR/CR/SV/UF

[dann frazier]

From: Vadim Lomovtsev <Vadim.Lomovtsev at cavium.com>

BugLink: https://bugs.launchpad.net/bugs/1736774

The Cavium ThunderX (CN8XXX) family of PCIe Root Ports does not advertise
an ACS capability.  However, the RTL internally implements similar
protection as if ACS had Request Redirection, Completion Redirection,
Source Validation, and Upstream Forwarding features enabled.

Change Cavium ACS capabilities quirk flags accordingly.

Fixes: b404bcfbf035 ("PCI: Add ACS quirk for all Cavium devices")
Signed-off-by: Vadim Lomovtsev <Vadim.Lomovtsev at cavium.com>
[bhelgaas: tidy changelog, comment, stable tag]
Signed-off-by: Bjorn Helgaas <bhelgaas at google.com>
Cc: stable at vger.kernel.org	# v4.6+: b77d537d00d0: PCI: Apply Cavium ACS quirk only to CN81xx/CN83xx/CN88xx devices
(cherry picked from commit 7f342678634f16795892677204366e835e450dda)
Signed-off-by: dann frazier <dann.frazier at canonical.com>
---
 drivers/pci/quirks.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 02b009426670..fcf734231c4d 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -4253,12 +4253,14 @@ static int pci_quirk_amd_sb_acs(struct pci_dev *dev, u16 acs_flags)
 static int pci_quirk_cavium_acs(struct pci_dev *dev, u16 acs_flags)
 {
 	/*
-	 * Cavium devices matching this quirk do not perform peer-to-peer
-	 * with other functions, allowing masking out these bits as if they
-	 * were unimplemented in the ACS capability.
+	 * Cavium root ports don't advertise an ACS capability.  However,
+	 * the RTL internally implements similar protection as if ACS had
+	 * Request Redirection, Completion Redirection, Source Validation,
+	 * and Upstream Forwarding features enabled.  Assert that the
+	 * hardware implements and enables equivalent ACS functionality for
+	 * these flags.
 	 */
-	acs_flags &= ~(PCI_ACS_SV | PCI_ACS_TB | PCI_ACS_RR |
-		       PCI_ACS_CR | PCI_ACS_UF | PCI_ACS_DT);
+	acs_flags &= ~(PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_SV | PCI_ACS_UF);
 
 	if (!((dev->device >= 0xa000) && (dev->device <= 0xa0ff)))
 		return -ENOTTY;
-- 
2.15.1