From 9f5a70f18c5893a30d6c339adc48de43c57dd7e2 Mon Sep 17 00:00:00 2001
From: Oza Pawandeep <poza@codeaurora.org>
Date: Thu, 17 May 2018 16:44:11 -0500
Subject: [PATCH] PCI: Add generic pcie_wait_for_link() interface
Git-commit: 9f5a70f18c5893a30d6c339adc48de43c57dd7e2
Patch-mainline: v4.18
References: FATE#325195

Clients such as hotplug and Downstream Port Containment (DPC) both need to
wait until a link becomes active or inactive.

Add a generic pcie_wait_link_active() interface and use it instead of
duplicating the code.

Signed-off-by: Oza Pawandeep <poza@codeaurora.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/pci/hotplug/pciehp_hpc.c |   20 +++-----------------
 drivers/pci/pci.c                |   29 +++++++++++++++++++++++++++++
 drivers/pci/pci.h                |    1 +
 drivers/pci/pcie/dpc.c           |   12 +-----------
 4 files changed, 34 insertions(+), 28 deletions(-)

--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -248,25 +248,11 @@ bool pciehp_check_link_active(struct con
 	return ret;
 }
 
-static void __pcie_wait_link_active(struct controller *ctrl, bool active)
-{
-	int timeout = 1000;
-
-	if (pciehp_check_link_active(ctrl) == active)
-		return;
-	while (timeout > 0) {
-		msleep(10);
-		timeout -= 10;
-		if (pciehp_check_link_active(ctrl) == active)
-			return;
-	}
-	ctrl_dbg(ctrl, "Data Link Layer Link Active not %s in 1000 msec\n",
-			active ? "set" : "cleared");
-}
-
 static void pcie_wait_link_active(struct controller *ctrl)
 {
-	__pcie_wait_link_active(ctrl, true);
+	struct pci_dev *pdev = ctrl_dev(ctrl);
+
+	pcie_wait_for_link(pdev, true);
 }
 
 static bool pci_bus_check_dev(struct pci_bus *bus, int devfn)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4296,6 +4296,35 @@ static void pci_dev_restore(struct pci_d
 	if (err_handler && err_handler->reset_done)
 		err_handler->reset_done(dev);
 }
+/**
+ * pcie_wait_for_link - Wait until link is active or inactive
+ * @pdev: Bridge device
+ * @active: waiting for active or inactive?
+ *
+ * Use this to wait till link becomes active or inactive.
+ */
+bool pcie_wait_for_link(struct pci_dev *pdev, bool active)
+{
+	int timeout = 1000;
+	bool ret;
+	u16 lnk_status;
+
+	for (;;) {
+		pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
+		ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);
+		if (ret == active)
+			return true;
+		if (timeout <= 0)
+			break;
+		msleep(10);
+		timeout -= 10;
+	}
+
+	pci_info(pdev, "Data Link Layer Link Active not %s in 1000 msec\n",
+		 active ? "set" : "cleared");
+
+	return false;
+}
 
 /**
  * __pci_reset_function - reset a PCI device function
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -382,6 +382,7 @@ static inline void pcie_aspm_create_sysf
 static inline void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev) { }
 #endif
 
+bool pcie_wait_for_link(struct pci_dev *pdev, bool active);
 #ifdef CONFIG_PCIE_PTM
 void pci_ptm_init(struct pci_dev *dev);
 #else
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -91,19 +91,9 @@ static int dpc_wait_rp_inactive(struct d
 
 static void dpc_wait_link_inactive(struct dpc_dev *dpc)
 {
-	unsigned long timeout = jiffies + HZ;
 	struct pci_dev *pdev = dpc->dev->port;
-	struct device *dev = &dpc->dev->device;
-	u16 lnk_status;
 
-	pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
-	while (lnk_status & PCI_EXP_LNKSTA_DLLLA &&
-					!time_after(jiffies, timeout)) {
-		msleep(10);
-		pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
-	}
-	if (lnk_status & PCI_EXP_LNKSTA_DLLLA)
-		dev_warn(dev, "Link state not disabled for DPC event\n");
+	pcie_wait_for_link(pdev, false);
 }
 
 static void dpc_work(struct work_struct *work)