linux-kernel - [PATCH 4.19 225/267] PCI: Make ACS quirk implementations more uniform

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Message-Id: <20200619141659.498894885@linuxfoundation.org>
Date:   Fri, 19 Jun 2020 16:33:30 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Bjorn Helgaas <bhelgaas@...gle.com>,
        Logan Gunthorpe <logang@...tatee.com>,
        Alex Williamson <alex.williamson@...hat.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 225/267] PCI: Make ACS quirk implementations more uniform

From: Bjorn Helgaas <bhelgaas@...gle.com>

[ Upstream commit c8de8ed2dcaac82e5d76d467dc0b02e0ee79809b ]

The ACS quirks differ in needless ways, which makes them look more
different than they really are.

Reorder the ACS flags in order of definitions in the spec:

  PCI_ACS_SV   Source Validation
  PCI_ACS_TB   Translation Blocking
  PCI_ACS_RR   P2P Request Redirect
  PCI_ACS_CR   P2P Completion Redirect
  PCI_ACS_UF   Upstream Forwarding
  PCI_ACS_EC   P2P Egress Control
  PCI_ACS_DT   Direct Translated P2P

(PCIe r5.0, sec 7.7.8.2) and use similar code structure in all.  No
functional change intended.

Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
Reviewed-by: Logan Gunthorpe <logang@...tatee.com>
Reviewed-by: Alex Williamson <alex.williamson@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/pci/quirks.c | 41 +++++++++++++++++++----------------------
 1 file changed, 19 insertions(+), 22 deletions(-)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 502dca568d6c..ae62c0b058dd 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -4333,18 +4333,18 @@ static bool pci_quirk_cavium_acs_match(struct pci_dev *dev)
 
 static int pci_quirk_cavium_acs(struct pci_dev *dev, u16 acs_flags)
 {
+	if (!pci_quirk_cavium_acs_match(dev))
+		return -ENOTTY;
+
 	/*
-	 * Cavium root ports don't advertise an ACS capability.  However,
+	 * 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,
+	 * Source Validation, Request Redirection, Completion Redirection,
 	 * and Upstream Forwarding features enabled.  Assert that the
 	 * hardware implements and enables equivalent ACS functionality for
 	 * these flags.
 	 */
-	acs_flags &= ~(PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_SV | PCI_ACS_UF);
-
-	if (!pci_quirk_cavium_acs_match(dev))
-		return -ENOTTY;
+	acs_flags &= ~(PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF);
 
 	return acs_flags ? 0 : 1;
 }
@@ -4362,7 +4362,7 @@ static int pci_quirk_xgene_acs(struct pci_dev *dev, u16 acs_flags)
 }
 
 /*
- * Many Intel PCH root ports do provide ACS-like features to disable peer
+ * Many Intel PCH Root Ports do provide ACS-like features to disable peer
  * transactions and validate bus numbers in requests, but do not provide an
  * actual PCIe ACS capability.  This is the list of device IDs known to fall
  * into that category as provided by Intel in Red Hat bugzilla 1037684.
@@ -4410,37 +4410,34 @@ static bool pci_quirk_intel_pch_acs_match(struct pci_dev *dev)
 	return false;
 }
 
-#define INTEL_PCH_ACS_FLAGS (PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF | PCI_ACS_SV)
+#define INTEL_PCH_ACS_FLAGS (PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF)
 
 static int pci_quirk_intel_pch_acs(struct pci_dev *dev, u16 acs_flags)
 {
-	u16 flags = dev->dev_flags & PCI_DEV_FLAGS_ACS_ENABLED_QUIRK ?
-		    INTEL_PCH_ACS_FLAGS : 0;
-
 	if (!pci_quirk_intel_pch_acs_match(dev))
 		return -ENOTTY;
 
-	return acs_flags & ~flags ? 0 : 1;
+	if (dev->dev_flags & PCI_DEV_FLAGS_ACS_ENABLED_QUIRK)
+		acs_flags &= ~(INTEL_PCH_ACS_FLAGS);
+
+	return acs_flags ? 0 : 1;
 }
 
 /*
- * These QCOM root ports do provide ACS-like features to disable peer
+ * These QCOM Root Ports do provide ACS-like features to disable peer
  * transactions and validate bus numbers in requests, but do not provide an
  * actual PCIe ACS capability.  Hardware supports source validation but it
  * will report the issue as Completer Abort instead of ACS Violation.
- * Hardware doesn't support peer-to-peer and each root port is a root
- * complex with unique segment numbers.  It is not possible for one root
- * port to pass traffic to another root port.  All PCIe transactions are
- * terminated inside the root port.
+ * Hardware doesn't support peer-to-peer and each Root Port is a Root
+ * Complex with unique segment numbers.  It is not possible for one Root
+ * Port to pass traffic to another Root Port.  All PCIe transactions are
+ * terminated inside the Root Port.
  */
 static int pci_quirk_qcom_rp_acs(struct pci_dev *dev, u16 acs_flags)
 {
-	u16 flags = (PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF | PCI_ACS_SV);
-	int ret = acs_flags & ~flags ? 0 : 1;
-
-	pci_info(dev, "Using QCOM ACS Quirk (%d)\n", ret);
+	acs_flags &= ~(PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF);
 
-	return ret;
+	return acs_flags ? 0 : 1;
 }
 
 /*
-- 
2.25.1