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From:   Oza Pawandeep <poza@codeaurora.org>
To:     Bjorn Helgaas <bhelgaas@google.com>,
        Philippe Ombredanne <pombredanne@nexb.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Kate Stewart <kstewart@linuxfoundation.org>,
        linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
        Dongdong Liu <liudongdong3@huawei.com>,
        Keith Busch <keith.busch@intel.com>, Wei Zhang <wzhang@fb.com>,
        Sinan Kaya <okaya@codeaurora.org>,
        Timur Tabi <timur@codeaurora.org>
Cc:     Oza Pawandeep <poza@codeaurora.org>
Subject: [PATCH v15 8/9] PCI/DPC: Unify and plumb error handling into DPC
Date:   Thu,  3 May 2018 01:03:57 -0400
Message-Id: <1525323838-1735-9-git-send-email-poza@codeaurora.org>
In-Reply-To: <1525323838-1735-1-git-send-email-poza@codeaurora.org>
References: <1525323838-1735-1-git-send-email-poza@codeaurora.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Current DPC driver does not do recovery, e.g. calling end-point's driver's
callbacks, which sanitize the sw.

DPC driver implements link_reset callback, and calls pci_do_recovery().

Signed-off-by: Oza Pawandeep <poza@codeaurora.org>

diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 80ec384..aed7c9f 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -73,29 +73,21 @@ static void dpc_wait_link_inactive(struct dpc_dev *dpc)
 	pcie_wait_for_link(pdev, false);
 }
 
-static void dpc_work(struct work_struct *work)
+static pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
 {
-	struct dpc_dev *dpc = container_of(work, struct dpc_dev, work);
-	struct pci_dev *dev, *temp, *pdev = dpc->dev->port;
-	struct pci_bus *parent = pdev->subordinate;
-	u16 cap = dpc->cap_pos, ctl;
-
-	pci_lock_rescan_remove();
-	list_for_each_entry_safe_reverse(dev, temp, &parent->devices,
-					 bus_list) {
-		pci_dev_get(dev);
-		pci_dev_set_disconnected(dev, NULL);
-		if (pci_has_subordinate(dev))
-			pci_walk_bus(dev->subordinate,
-				     pci_dev_set_disconnected, NULL);
-		pci_stop_and_remove_bus_device(dev);
-		pci_dev_put(dev);
-	}
-	pci_unlock_rescan_remove();
+	struct dpc_dev *dpc;
+	struct pcie_device *pciedev;
+	struct device *devdpc;
+	u16 cap, ctl;
+
+	devdpc = pcie_port_find_device(pdev, PCIE_PORT_SERVICE_DPC);
+	pciedev = to_pcie_device(devdpc);
+	dpc = get_service_data(pciedev);
+	cap = dpc->cap_pos;
 
 	dpc_wait_link_inactive(dpc);
 	if (dpc->rp_extensions && dpc_wait_rp_inactive(dpc))
-		return;
+		return PCI_ERS_RESULT_DISCONNECT;
 	if (dpc->rp_extensions && dpc->rp_pio_status) {
 		pci_write_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_STATUS,
 				       dpc->rp_pio_status);
@@ -108,6 +100,17 @@ static void dpc_work(struct work_struct *work)
 	pci_read_config_word(pdev, cap + PCI_EXP_DPC_CTL, &ctl);
 	pci_write_config_word(pdev, cap + PCI_EXP_DPC_CTL,
 			      ctl | PCI_EXP_DPC_CTL_INT_EN);
+
+	return PCI_ERS_RESULT_RECOVERED;
+}
+
+static void dpc_work(struct work_struct *work)
+{
+	struct dpc_dev *dpc = container_of(work, struct dpc_dev, work);
+	struct pci_dev *pdev = dpc->dev->port;
+
+	/* From DPC point of view error is always FATAL. */
+	pcie_do_recovery(pdev, DPC_FATAL);
 }
 
 static void dpc_process_rp_pio_error(struct dpc_dev *dpc)
@@ -288,6 +291,7 @@ static struct pcie_port_service_driver dpcdriver = {
 	.service	= PCIE_PORT_SERVICE_DPC,
 	.probe		= dpc_probe,
 	.remove		= dpc_remove,
+	.reset_link	= dpc_reset_link,
 };
 
 static int __init dpc_service_init(void)
diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index 877785d..526aba8 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -181,11 +181,12 @@ static pci_ers_result_t default_reset_link(struct pci_dev *dev)
 	return PCI_ERS_RESULT_RECOVERED;
 }
 
-static pci_ers_result_t reset_link(struct pci_dev *dev)
+static pci_ers_result_t reset_link(struct pci_dev *dev, int severity)
 {
 	struct pci_dev *udev;
 	pci_ers_result_t status;
 	struct pcie_port_service_driver *driver;
+	u32 service;
 
 	if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
 		/* Reset this port for all subordinates */
@@ -196,7 +197,12 @@ static pci_ers_result_t reset_link(struct pci_dev *dev)
 	}
 
 	/* Use the aer driver of the component firstly */
-	driver = pcie_port_find_service(udev, PCIE_PORT_SERVICE_AER);
+	if (severity == DPC_FATAL)
+		service = PCIE_PORT_SERVICE_DPC;
+	else
+		service = PCIE_PORT_SERVICE_AER;
+
+	driver = pcie_port_find_service(udev, service);
 
 	if (driver && driver->reset_link) {
 		status = driver->reset_link(udev);
@@ -302,7 +308,7 @@ static pci_ers_result_t do_fatal_recovery(struct pci_dev *dev, int severity)
 		pci_dev_put(pdev);
 	}
 
-	result = reset_link(udev);
+	result = reset_link(udev, severity);
 	if (result == PCI_ERS_RESULT_RECOVERED)
 		if (pcie_wait_for_link(udev, true))
 			pci_rescan_bus(udev->bus);
@@ -326,7 +332,8 @@ void pcie_do_recovery(struct pci_dev *dev, int severity)
 	pci_ers_result_t status;
 	enum pci_channel_state state;
 
-	if (severity == AER_FATAL) {
+	if ((severity == AER_FATAL) ||
+	   (severity == DPC_FATAL)) {
 		status = do_fatal_recovery(dev, severity);
 		if (status != PCI_ERS_RESULT_RECOVERED)
 			goto failed;
diff --git a/include/linux/aer.h b/include/linux/aer.h
index 8f87bbe..0c506fe 100644
--- a/include/linux/aer.h
+++ b/include/linux/aer.h
@@ -14,6 +14,7 @@
 #define AER_NONFATAL			0
 #define AER_FATAL			1
 #define AER_CORRECTABLE			2
+#define DPC_FATAL			4
 
 struct pci_dev;
 
-- 
2.7.4