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From:   Kai-Heng Feng <kai.heng.feng@canonical.com>
To:     bhelgaas@google.com
Cc:     mika.westerberg@linux.intel.com, koba.ko@canonical.com,
        Kai-Heng Feng <kai.heng.feng@canonical.com>,
        Russell Currey <ruscur@russell.cc>,
        "Oliver O'Halloran" <oohall@gmail.com>,
        linuxppc-dev@lists.ozlabs.org, linux-pci@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH v2 2/2] PCI/DPC: Disable DPC service when link is in L2/L3 ready, L2 and L3 state
Date:   Thu, 27 Jan 2022 10:54:18 +0800
Message-Id: <20220127025418.1989642-2-kai.heng.feng@canonical.com>
In-Reply-To: <20220127025418.1989642-1-kai.heng.feng@canonical.com>
References: <20220127025418.1989642-1-kai.heng.feng@canonical.com>
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Since TLP and DLLP transmission is disabled for a Link in L2/L3 Ready,
L2 and L3 (i.e. device in D3hot and D3cold), and DPC depends on AER, so
also disable DPC here.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
v2:
 - Wording change.
 - Empty line dropped.

 drivers/pci/pcie/dpc.c | 60 +++++++++++++++++++++++++++++++-----------
 1 file changed, 44 insertions(+), 16 deletions(-)

diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 3e9afee02e8d1..414258967f08e 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -343,13 +343,33 @@ void pci_dpc_init(struct pci_dev *pdev)
 	}
 }
 
+static void dpc_enable(struct pcie_device *dev)
+{
+	struct pci_dev *pdev = dev->port;
+	u16 ctl;
+
+	pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, &ctl);
+	ctl = (ctl & 0xfff4) | PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN;
+	pci_write_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, ctl);
+}
+
+static void dpc_disable(struct pcie_device *dev)
+{
+	struct pci_dev *pdev = dev->port;
+	u16 ctl;
+
+	pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, &ctl);
+	ctl &= ~(PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN);
+	pci_write_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, ctl);
+}
+
 #define FLAG(x, y) (((x) & (y)) ? '+' : '-')
 static int dpc_probe(struct pcie_device *dev)
 {
 	struct pci_dev *pdev = dev->port;
 	struct device *device = &dev->device;
 	int status;
-	u16 ctl, cap;
+	u16 cap;
 
 	if (!pcie_aer_is_native(pdev) && !pcie_ports_dpc_native)
 		return -ENOTSUPP;
@@ -364,10 +384,7 @@ static int dpc_probe(struct pcie_device *dev)
 	}
 
 	pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CAP, &cap);
-	pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, &ctl);
-
-	ctl = (ctl & 0xfff4) | PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN;
-	pci_write_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, ctl);
+	dpc_enable(dev);
 	pci_info(pdev, "enabled with IRQ %d\n", dev->irq);
 
 	pci_info(pdev, "error containment capabilities: Int Msg #%d, RPExt%c PoisonedTLP%c SwTrigger%c RP PIO Log %d, DL_ActiveErr%c\n",
@@ -380,22 +397,33 @@ static int dpc_probe(struct pcie_device *dev)
 	return status;
 }
 
-static void dpc_remove(struct pcie_device *dev)
+static int dpc_suspend(struct pcie_device *dev)
 {
-	struct pci_dev *pdev = dev->port;
-	u16 ctl;
+	dpc_disable(dev);
+	return 0;
+}
 
-	pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, &ctl);
-	ctl &= ~(PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN);
-	pci_write_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, ctl);
+static int dpc_resume(struct pcie_device *dev)
+{
+	dpc_enable(dev);
+	return 0;
+}
+
+static void dpc_remove(struct pcie_device *dev)
+{
+	dpc_disable(dev);
 }
 
 static struct pcie_port_service_driver dpcdriver = {
-	.name		= "dpc",
-	.port_type	= PCIE_ANY_PORT,
-	.service	= PCIE_PORT_SERVICE_DPC,
-	.probe		= dpc_probe,
-	.remove		= dpc_remove,
+	.name			= "dpc",
+	.port_type		= PCIE_ANY_PORT,
+	.service		= PCIE_PORT_SERVICE_DPC,
+	.probe			= dpc_probe,
+	.suspend		= dpc_suspend,
+	.resume			= dpc_resume,
+	.runtime_suspend	= dpc_suspend,
+	.runtime_resume		= dpc_resume,
+	.remove			= dpc_remove,
 };
 
 int __init pcie_dpc_init(void)
-- 
2.33.1