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From:   Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@linux.intel.com>
To:     bhelgaas@google.com
Cc:     linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
        ashok.raj@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com,
        knsathya@kernel.org
Subject: [PATCH v11 3/5] ACPI/PCI: Ignore _OSC DPC negotiation result if pcie_ports_dpc_native is set.
Date:   Mon, 26 Oct 2020 19:57:06 -0700
Message-Id: <0ec11f2b7470070768886a138f2a755620725a06.1603766889.git.sathyanarayanan.kuppuswamy@linux.intel.com>
In-Reply-To: <cover.1603766889.git.sathyanarayanan.kuppuswamy@linux.intel.com>
References: <cover.1603766889.git.sathyanarayanan.kuppuswamy@linux.intel.com>
In-Reply-To: <cover.1603766889.git.sathyanarayanan.kuppuswamy@linux.intel.com>
References: <cover.1603766889.git.sathyanarayanan.kuppuswamy@linux.intel.com>
Precedence: bulk

pcie_ports_dpc_native is set only if user requests native handling
of PCIe DPC capability via pcie_port_setup command line option.
User input takes precedence over _OSC based control negotiation
result. So consider the _OSC negotiated result for DPC ownership
only if pcie_ports_dpc_native is unset.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 drivers/acpi/pci_root.c         | 8 ++++++--
 drivers/pci/pcie/dpc.c          | 3 ++-
 drivers/pci/pcie/portdrv.h      | 2 --
 drivers/pci/pcie/portdrv_core.c | 2 +-
 include/linux/pci.h             | 2 ++
 5 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index a9e6b782622d..2e2bc80c42fe 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -933,8 +933,12 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
 			  host_bridge->native_pme);
 		OSC_OWNER(ctrl, OSC_PCI_EXPRESS_LTR_CONTROL,
 			  host_bridge->native_ltr);
-		OSC_OWNER(ctrl, OSC_PCI_EXPRESS_DPC_CONTROL,
-			  host_bridge->native_dpc);
+		if (pcie_ports_dpc_native)
+			dev_warn(&bus->dev, "OS forcibly taking over DPC\n");
+		else
+			OSC_OWNER(ctrl, OSC_PCI_EXPRESS_DPC_CONTROL,
+				  host_bridge->native_dpc);
+
 	}
 
 	if (!(root->osc_control_set & OSC_PCI_SHPC_NATIVE_HP_CONTROL))
diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index e05aba86a317..21f77420632b 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -283,11 +283,12 @@ void pci_dpc_init(struct pci_dev *pdev)
 static int dpc_probe(struct pcie_device *dev)
 {
 	struct pci_dev *pdev = dev->port;
+	struct pci_host_bridge *host = pci_find_host_bridge(pdev->bus);
 	struct device *device = &dev->device;
 	int status;
 	u16 ctl, cap;
 
-	if (!pcie_aer_is_native(pdev) && !pcie_ports_dpc_native)
+	if (!pcie_aer_is_native(pdev) && !host->native_dpc)
 		return -ENOTSUPP;
 
 	status = devm_request_threaded_irq(device, dev->irq, dpc_irq,
diff --git a/drivers/pci/pcie/portdrv.h b/drivers/pci/pcie/portdrv.h
index af7cf237432a..0ac20feef24e 100644
--- a/drivers/pci/pcie/portdrv.h
+++ b/drivers/pci/pcie/portdrv.h
@@ -25,8 +25,6 @@
 
 #define PCIE_PORT_DEVICE_MAXSERVICES   5
 
-extern bool pcie_ports_dpc_native;
-
 #ifdef CONFIG_PCIEAER
 int pcie_aer_init(void);
 int pcie_aer_is_native(struct pci_dev *dev);
diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
index ccd5e0ce5605..2c0278f0fdcc 100644
--- a/drivers/pci/pcie/portdrv_core.c
+++ b/drivers/pci/pcie/portdrv_core.c
@@ -253,7 +253,7 @@ static int get_port_device_capability(struct pci_dev *dev)
 	 */
 	if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
 	    pci_aer_available() &&
-	    (pcie_ports_dpc_native || (services & PCIE_PORT_SERVICE_AER)))
+	    (host->native_dpc || (services & PCIE_PORT_SERVICE_AER)))
 		services |= PCIE_PORT_SERVICE_DPC;
 
 	if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM ||
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 22207a79762c..388121ec88b5 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1559,9 +1559,11 @@ static inline int pci_irqd_intx_xlate(struct irq_domain *d,
 #ifdef CONFIG_PCIEPORTBUS
 extern bool pcie_ports_disabled;
 extern bool pcie_ports_native;
+extern bool pcie_ports_dpc_native;
 #else
 #define pcie_ports_disabled	true
 #define pcie_ports_native	false
+#define pcie_ports_dpc_native	false
 #endif
 
 #define PCIE_LINK_STATE_L0S		BIT(0)
-- 
2.17.1