linux-kernel - [PATCH v9 3/5] ACPI/PCI: Ignore _OSC DPC negotiation result if pcie_ports_dpc

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Date:   Fri, 18 Sep 2020 12:58:32 -0700
From:   sathyanarayanan.kuppuswamy@...ux.intel.com
To:     bhelgaas@...gle.com
Cc:     linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        ashok.raj@...el.com, sathyanarayanan.kuppuswamy@...ux.intel.com
Subject: [PATCH v9 3/5] ACPI/PCI: Ignore _OSC DPC negotiation result if pcie_ports_dpc_native is set.

From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>

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@...ux.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 9749b7abdd7e..979d03494476 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -935,8 +935,12 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
 			    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))
 		host_bridge->native_shpc_hotplug = 0;
 
diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index daa9a4153776..5b1025a2994d 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -280,11 +280,12 @@ 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 835530605c0d..dc03b6c65742 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1556,9 +1556,11 @@ 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