Re: [PATCH v10 6/7] PCI: Unify wait for link active into generic pci

2018-02-22 Thread poza

On 2018-02-23 00:13, Christoph Hellwig wrote:


+/**
+ * pci__wait_for_link - Wait for link till its active/inactive


typo - just wants a single underscore.


+   pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
+   ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);


no need for the !! when assigning to a boolean.


bool is 8 bit, while
#define  PCI_EXP_LNKSTA_DLLLA   0x2000  /* Data Link Layer Link Active */
so I think we need it. otherwise it will treat lnk_status & 
PCI_EXP_LNKSTA_DLLLA as 0 even if 13th bit is set.





+
+   while ((ret != active) && (timeout > 0)) {


No need for either pair of inner braces.


+   msleep(10);
+   timeout -= 10;
+   pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
+   ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);


Same as above.


+   }
+
+   if (ret == active)
+   return true;


Seems like the structure is a bit odd.  Why not:

for (;;) {
pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
if ((lnk_status & PCI_EXP_LNKSTA_DLLLA) == active)
return true;
if (timeout <= 0)
break;
timeout -= 10;
}


Thanks for suggestion, will do this way. thanks.
Regards,
Oza.




Re: [PATCH v10 6/7] PCI: Unify wait for link active into generic pci

2018-02-22 Thread Christoph Hellwig
>  
> +/**
> + * pci__wait_for_link - Wait for link till its active/inactive

typo - just wants a single underscore.

> + pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
> + ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);

no need for the !! when assigning to a boolean.

> +
> + while ((ret != active) && (timeout > 0)) {

No need for either pair of inner braces.

> + msleep(10);
> + timeout -= 10;
> + pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
> + ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);

Same as above.

> + }
> +
> + if (ret == active)
> + return true;

Seems like the structure is a bit odd.  Why not:

for (;;) {
pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
if ((lnk_status & PCI_EXP_LNKSTA_DLLLA) == active)
return true;
if (timeout <= 0)
break;
timeout -= 10;
}



[PATCH v10 6/7] PCI: Unify wait for link active into generic pci

2018-02-22 Thread Oza Pawandeep
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 

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..5440696 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4176,6 +4176,40 @@ 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;
+
+   pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
+   ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);
+
+   while ((ret != active) && (timeout > 0)) {
+   msleep(10);
+   timeout -= 10;
+   pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
+   ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);
+   }
+
+   if (ret == active)
+   return true;
+
+   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 208b427..0524bd3 100644
--- a/drivers/pci/pcie/pcie-dpc.c
+++ b/drivers/pci/pcie/pcie-dpc.c
@@ -122,19 +122,9 @@ 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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