diff mbox

[v6,7/7] PCI: Unify wait for link active into generic pci

Message ID 1516360204-1586-8-git-send-email-poza@codeaurora.org (mailing list archive)
State New, archived
Delegated to: Bjorn Helgaas
Headers show

Commit Message

Oza Pawandeep Jan. 19, 2018, 11:10 a.m. UTC 
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@codeaurora.org>

Comments

Sinan Kaya Jan. 19, 2018, 2:08 p.m. UTC | #1 
On 1/19/2018 6:10 AM, Oza Pawandeep wrote:
> +check_link:
> +	pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
> +	ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);
> +
> +	if (ret == active) {
> +		dev_printk(KERN_DEBUG, &pdev->dev,
> +			   "%s: lnk_status = %x\n", __func__, lnk_status);
> +		return true;
> +	}
> +
> +	while (timeout > 0) {
> +		msleep(10);
> +		timeout -= 10;
> +		goto check_link;
> +	}


this is weird. 

I think following is a simpler approach.

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);
}
Sinan Kaya Jan. 19, 2018, 2:17 p.m. UTC | #2 
On 1/19/2018 6:10 AM, Oza Pawandeep wrote:
> +++ b/drivers/pci/pcie/pcie-dpc.c
> @@ -150,37 +150,9 @@ static void dpc_wait_link_inactive(struct dpc_dev *dpc)
>  	struct pci_dev *pdev = dpc->dev->port;
>  	struct device *dev = &dpc->dev->device;
>  	u16 lnk_status;
> +	bool active = false;
>  
> -	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");
> -}

I think you should reorder 6 and 7 to eliminate this.
Stefan Roese Jan. 19, 2018, 2:19 p.m. UTC | #3 
On 19.01.2018 12:10, Oza Pawandeep wrote:
> 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@codeaurora.org>
> 
> diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
> index 7bab060..26afeff 100644
> --- a/drivers/pci/hotplug/pciehp_hpc.c
> +++ b/drivers/pci/hotplug/pciehp_hpc.c
> @@ -245,25 +245,12 @@ 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);
> +	bool active = true;
>   
> -static void pcie_wait_link_active(struct controller *ctrl)
> -{
> -	__pcie_wait_link_active(ctrl, true);
> +	return pci_wait_for_link(pdev, active);
>   }
>   
>   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 4a7c686..0de83ea 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -2805,7 +2805,7 @@ static void pci_std_enable_acs(struct pci_dev *dev)
>   	pci_read_config_word(dev, pos + PCI_ACS_CTRL, &ctrl);
>   
>   	/* Source Validation */
> -	ctrl |= (cap & PCI_ACS_SV);
> +//	ctrl |= (cap & PCI_ACS_SV);

Could it be, that you missed to fix / clean something up here?

Thanks,
Stefan
Oza Pawandeep Jan. 19, 2018, 3:58 p.m. UTC | #4 
On 2018-01-19 19:49, Stefan Roese wrote:
> On 19.01.2018 12:10, Oza Pawandeep wrote:
>> 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@codeaurora.org>
>> 
>> diff --git a/drivers/pci/hotplug/pciehp_hpc.c 
>> b/drivers/pci/hotplug/pciehp_hpc.c
>> index 7bab060..26afeff 100644
>> --- a/drivers/pci/hotplug/pciehp_hpc.c
>> +++ b/drivers/pci/hotplug/pciehp_hpc.c
>> @@ -245,25 +245,12 @@ 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);
>> +	bool active = true;
>> 
>> -static void pcie_wait_link_active(struct controller *ctrl)
>> -{
>> -	__pcie_wait_link_active(ctrl, true);
>> +	return pci_wait_for_link(pdev, active);
>>   }
>> 
>>   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 4a7c686..0de83ea 100644
>> --- a/drivers/pci/pci.c
>> +++ b/drivers/pci/pci.c
>> @@ -2805,7 +2805,7 @@ static void pci_std_enable_acs(struct pci_dev 
>> *dev)
>>   	pci_read_config_word(dev, pos + PCI_ACS_CTRL, &ctrl);
>> 
>>   	/* Source Validation */
>> -	ctrl |= (cap & PCI_ACS_SV);
>> +//	ctrl |= (cap & PCI_ACS_SV);
> 
> Could it be, that you missed to fix / clean something up here?
> 
> Thanks,
> Stefan

yes, will correct this and re-post.

Regards,
Oza.
Oza Pawandeep Jan. 19, 2018, 4:22 p.m. UTC | #5 
On 2018-01-19 19:47, Sinan Kaya wrote:
> On 1/19/2018 6:10 AM, Oza Pawandeep wrote:
>> +++ b/drivers/pci/pcie/pcie-dpc.c
>> @@ -150,37 +150,9 @@ static void dpc_wait_link_inactive(struct dpc_dev 
>> *dpc)
>>  	struct pci_dev *pdev = dpc->dev->port;
>>  	struct device *dev = &dpc->dev->device;
>>  	u16 lnk_status;
>> +	bool active = false;
>> 
>> -	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");
>> -}
> 
> I think you should reorder 6 and 7 to eliminate this.

Sure will reorder them

Regards,
Oza.
diff mbox

Patch

diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 7bab060..26afeff 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -245,25 +245,12 @@  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);
+	bool active = true;
 
-static void pcie_wait_link_active(struct controller *ctrl)
-{
-	__pcie_wait_link_active(ctrl, true);
+	return pci_wait_for_link(pdev, active);
 }
 
 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 4a7c686..0de83ea 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2805,7 +2805,7 @@  static void pci_std_enable_acs(struct pci_dev *dev)
 	pci_read_config_word(dev, pos + PCI_ACS_CTRL, &ctrl);
 
 	/* Source Validation */
-	ctrl |= (cap & PCI_ACS_SV);
+//	ctrl |= (cap & PCI_ACS_SV);
 
 	/* P2P Request Redirect */
 	ctrl |= (cap & PCI_ACS_RR);
@@ -4079,6 +4079,43 @@  static int pci_pm_reset(struct pci_dev *dev, int probe)
 	return 0;
 }
 
+/**
+ * pci__wait_for_link - Wait for link till its active/inactive
+ * @dev: 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;
+
+check_link:
+	pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
+	ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);
+
+	if (ret == active) {
+		dev_printk(KERN_DEBUG, &pdev->dev,
+			   "%s: lnk_status = %x\n", __func__, lnk_status);
+		return true;
+	}
+
+	while (timeout > 0) {
+		msleep(10);
+		timeout -= 10;
+		goto check_link;
+	}
+	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 1b06a8e..67502a5 100644
--- a/drivers/pci/pcie/pcie-dpc.c
+++ b/drivers/pci/pcie/pcie-dpc.c
@@ -150,37 +150,9 @@  static void dpc_wait_link_inactive(struct dpc_dev *dpc)
 	struct pci_dev *pdev = dpc->dev->port;
 	struct device *dev = &dpc->dev->device;
 	u16 lnk_status;
+	bool active = false;
 
-	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");
-}
-
-static bool dpc_wait_link_active(struct pci_dev *pdev)
-{
-	unsigned long timeout = jiffies + HZ;
-	u16 lnk_status;
-	bool ret = true;
-
-	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(&pdev->dev, "Link state not enabled after DPC event\n");
-		ret = false;
-	}
-
-	return ret;
+	pci_wait_for_link(pdev, active);
 }
 
 /**
@@ -191,7 +163,9 @@  static bool dpc_wait_link_active(struct pci_dev *pdev)
  */
 static void dpc_error_resume(struct pci_dev *pdev)
 {
-	if (dpc_wait_link_active(pdev)) {
+	bool active = true;
+
+	if (pci_wait_for_link(pdev, active)) {
 		pci_lock_rescan_remove();
 		pci_rescan_bus(pdev->bus);
 		pci_unlock_rescan_remove();
diff --git a/include/linux/pci.h b/include/linux/pci.h
index c170c92..f9f6a3d 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1201,6 +1201,7 @@  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);