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

[poza]

On 2018-02-24 21:11, Bjorn Helgaas wrote:

In subject:

s/pci/PCI/

sure.

On Fri, Feb 23, 2018 at 01:54:03PM +0530, Oza Pawandeep wrote:

Clients such as pciehp, dpc are using pcie_wait_link_active, which waits

till the link becomes active or inactive.

Use "()" after function names so we have a visual clue that they are
functions.

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

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

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

s/its/it's/

sure.

+ * @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)

I think this should be "pcie_wait_for_link()".  There's no concept of a
link in conventional PCI.

+{
+       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,

pci_info().  Distros often seem to have logging configured so
KERN_DEBUG things aren't captured, and this definitely seems worth
capturing.

+                  "Data Link Layer Link Active not %s in 1000 msec\n",
+                  active ? "set" : "cleared");
+
+       return false;
+}
+EXPORT_SYMBOL(pci_wait_for_link);

I don't think this needs to be exported.

sure.

 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);

I don't think this needs to be available outside the PCI core, so this
could probably be declared in drivers/pci/pci.h

thanks, will move it.

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

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