[PATCH v11 6/7] PCI: Unify wait for link active into generic pci

From: Oza Pawandeep
Date: Fri Feb 23 2018 - 03:25:04 EST


Clients such as pciehp, dpc are using pcie_wait_link_active, which waits
till the link becomes active or inactive.

Made generic function and moved it to drivers/pci/pci.c

Signed-off-by: Oza Pawandeep <poza@xxxxxxxxxxxxxx>

diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 18a42f8..de9b0ea 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -231,25 +231,11 @@ bool pciehp_check_link_active(struct controller *ctrl)
return ret;
}

-static void __pcie_wait_link_active(struct controller *ctrl, bool active)
+static bool pcie_wait_link_active(struct controller *ctrl)
{
- 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");
-}
+ struct pci_dev *pdev = ctrl_dev(ctrl);

-static void pcie_wait_link_active(struct controller *ctrl)
-{
- __pcie_wait_link_active(ctrl, true);
+ return pci_wait_for_link(pdev, true);
}

static bool pci_bus_check_dev(struct pci_bus *bus, int devfn)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index f6a4dd1..f8d44b4 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4176,6 +4176,37 @@ static int pci_pm_reset(struct pci_dev *dev, int probe)
return 0;
}

+/**
+ * pci_wait_for_link - Wait for link till its active/inactive
+ * @pdev: Bridge device
+ * @active: waiting for active or inactive ?
+ *
+ * Use this to wait till link becomes active or inactive.
+ */
+bool pci_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;
+ timeout -= 10;
+ }
+
+ dev_printk(KERN_DEBUG, &pdev->dev,
+ "Data Link Layer Link Active not %s in 1000 msec\n",
+ active ? "set" : "cleared");
+
+ return false;
+}
+EXPORT_SYMBOL(pci_wait_for_link);
+
void pci_reset_secondary_bus(struct pci_dev *dev)
{
u16 ctrl;
diff --git a/drivers/pci/pcie/pcie-dpc.c b/drivers/pci/pcie/pcie-dpc.c
index 5c01c63..e15bcda 100644
--- a/drivers/pci/pcie/pcie-dpc.c
+++ b/drivers/pci/pcie/pcie-dpc.c
@@ -120,19 +120,9 @@ static int dpc_wait_rp_inactive(struct dpc_dev *dpc)

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");
+ pci_wait_for_link(pdev, false);
}

/**
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 024a1be..cb674c3 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1195,6 +1195,7 @@ int pci_add_ext_cap_save_buffer(struct pci_dev *dev,
int pci_request_selected_regions(struct pci_dev *, int, const char *);
int pci_request_selected_regions_exclusive(struct pci_dev *, int, const char *);
void pci_release_selected_regions(struct pci_dev *, int);
+bool pci_wait_for_link(struct pci_dev *pdev, bool active);

/* drivers/pci/bus.c */
struct pci_bus *pci_bus_get(struct pci_bus *bus);
--
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