diff mbox

PCI: altera: Poll for link training status after retraining the link

Message ID 1471241162-23021-1-git-send-email-lftan@altera.com (mailing list archive)
State New, archived
Headers show

Commit Message

Ley Foon Tan Aug. 15, 2016, 6:06 a.m. UTC
Poll for link training status is cleared before poll for link up status.
This can help to get the reliable link up status, especially when PCIe
is in Gen 3 speed.

Signed-off-by: Ley Foon Tan <lftan@altera.com>
---
 drivers/pci/host/pcie-altera.c | 45 ++++++++++++++++++++++++++++++++++--------
 1 file changed, 37 insertions(+), 8 deletions(-)

Comments

Bjorn Helgaas Aug. 18, 2016, 8:19 p.m. UTC | #1
On Mon, Aug 15, 2016 at 02:06:02PM +0800, Ley Foon Tan wrote:
> Poll for link training status is cleared before poll for link up status.
> This can help to get the reliable link up status, especially when PCIe
> is in Gen 3 speed.
> 
> Signed-off-by: Ley Foon Tan <lftan@altera.com>

Applied to pci/host-altera for v4.9, thanks!

> ---
>  drivers/pci/host/pcie-altera.c | 45 ++++++++++++++++++++++++++++++++++--------
>  1 file changed, 37 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/pci/host/pcie-altera.c b/drivers/pci/host/pcie-altera.c
> index 2b78376..58eef99 100644
> --- a/drivers/pci/host/pcie-altera.c
> +++ b/drivers/pci/host/pcie-altera.c
> @@ -61,7 +61,8 @@
>  #define TLP_LOOP			500
>  #define RP_DEVFN			0
>  
> -#define LINK_UP_TIMEOUT			5000
> +#define LINK_UP_TIMEOUT			HZ
> +#define LINK_RETRAIN_TIMEOUT		HZ
>  
>  #define INTX_NUM			4
>  
> @@ -99,11 +100,44 @@ static bool altera_pcie_link_is_up(struct altera_pcie *pcie)
>  	return !!((cra_readl(pcie, RP_LTSSM) & RP_LTSSM_MASK) == LTSSM_L0);
>  }
>  
> +static void altera_wait_link_retrain(struct pci_dev *dev)
> +{
> +	u16 reg16;
> +	unsigned long start_jiffies;
> +	struct altera_pcie *pcie = dev->bus->sysdata;
> +
> +	/* Wait for link training end. */
> +	start_jiffies = jiffies;
> +	for (;;) {
> +		pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &reg16);
> +		if (!(reg16 & PCI_EXP_LNKSTA_LT))
> +			break;
> +
> +		if (time_after(jiffies, start_jiffies + LINK_RETRAIN_TIMEOUT)) {
> +			dev_err(&pcie->pdev->dev, "link retrain timeout\n");
> +			break;
> +		}
> +		udelay(100);
> +	}
> +
> +	/* Wait for link is up */
> +	start_jiffies = jiffies;
> +	for (;;) {
> +		if (altera_pcie_link_is_up(pcie))
> +			break;
> +
> +		if (time_after(jiffies, start_jiffies + LINK_UP_TIMEOUT)) {
> +			dev_err(&pcie->pdev->dev, "link up timeout\n");
> +			break;
> +		}
> +		udelay(100);
> +	}
> +}
> +
>  static void altera_pcie_retrain(struct pci_dev *dev)
>  {
>  	u16 linkcap, linkstat;
>  	struct altera_pcie *pcie = dev->bus->sysdata;
> -	int timeout =  0;
>  
>  	if (!altera_pcie_link_is_up(pcie))
>  		return;
> @@ -121,12 +155,7 @@ static void altera_pcie_retrain(struct pci_dev *dev)
>  	if ((linkstat & PCI_EXP_LNKSTA_CLS) == PCI_EXP_LNKSTA_CLS_2_5GB) {
>  		pcie_capability_set_word(dev, PCI_EXP_LNKCTL,
>  					 PCI_EXP_LNKCTL_RL);
> -		while (!altera_pcie_link_is_up(pcie)) {
> -			timeout++;
> -			if (timeout > LINK_UP_TIMEOUT)
> -				break;
> -			udelay(5);
> -		}
> +		altera_wait_link_retrain(dev);
>  	}
>  }
>  DECLARE_PCI_FIXUP_EARLY(0x1172, PCI_ANY_ID, altera_pcie_retrain);
> -- 
> 1.8.2.1
> 
> --
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Ley Foon Tan Aug. 19, 2016, 7:55 a.m. UTC | #2
On Fri, Aug 19, 2016 at 4:19 AM, Bjorn Helgaas <helgaas@kernel.org> wrote:
> On Mon, Aug 15, 2016 at 02:06:02PM +0800, Ley Foon Tan wrote:
>> Poll for link training status is cleared before poll for link up status.
>> This can help to get the reliable link up status, especially when PCIe
>> is in Gen 3 speed.
>>
>> Signed-off-by: Ley Foon Tan <lftan@altera.com>
>
> Applied to pci/host-altera for v4.9, thanks!

Thanks, Bjorn.

>
>> ---
>>  drivers/pci/host/pcie-altera.c | 45 ++++++++++++++++++++++++++++++++++--------
>>  1 file changed, 37 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/pci/host/pcie-altera.c b/drivers/pci/host/pcie-altera.c
>> index 2b78376..58eef99 100644
>> --- a/drivers/pci/host/pcie-altera.c
>> +++ b/drivers/pci/host/pcie-altera.c
>> @@ -61,7 +61,8 @@
>>  #define TLP_LOOP                     500
>>  #define RP_DEVFN                     0
>>
>> -#define LINK_UP_TIMEOUT                      5000
>> +#define LINK_UP_TIMEOUT                      HZ
>> +#define LINK_RETRAIN_TIMEOUT         HZ
>>
>>  #define INTX_NUM                     4
>>
>> @@ -99,11 +100,44 @@ static bool altera_pcie_link_is_up(struct altera_pcie *pcie)
>>       return !!((cra_readl(pcie, RP_LTSSM) & RP_LTSSM_MASK) == LTSSM_L0);
>>  }
>>
>> +static void altera_wait_link_retrain(struct pci_dev *dev)
>> +{
>> +     u16 reg16;
>> +     unsigned long start_jiffies;
>> +     struct altera_pcie *pcie = dev->bus->sysdata;
>> +
>> +     /* Wait for link training end. */
>> +     start_jiffies = jiffies;
>> +     for (;;) {
>> +             pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &reg16);
>> +             if (!(reg16 & PCI_EXP_LNKSTA_LT))
>> +                     break;
>> +
>> +             if (time_after(jiffies, start_jiffies + LINK_RETRAIN_TIMEOUT)) {
>> +                     dev_err(&pcie->pdev->dev, "link retrain timeout\n");
>> +                     break;
>> +             }
>> +             udelay(100);
>> +     }
>> +
>> +     /* Wait for link is up */
>> +     start_jiffies = jiffies;
>> +     for (;;) {
>> +             if (altera_pcie_link_is_up(pcie))
>> +                     break;
>> +
>> +             if (time_after(jiffies, start_jiffies + LINK_UP_TIMEOUT)) {
>> +                     dev_err(&pcie->pdev->dev, "link up timeout\n");
>> +                     break;
>> +             }
>> +             udelay(100);
>> +     }
>> +}
>> +
>>  static void altera_pcie_retrain(struct pci_dev *dev)
>>  {
>>       u16 linkcap, linkstat;
>>       struct altera_pcie *pcie = dev->bus->sysdata;
>> -     int timeout =  0;
>>
>>       if (!altera_pcie_link_is_up(pcie))
>>               return;
>> @@ -121,12 +155,7 @@ static void altera_pcie_retrain(struct pci_dev *dev)
>>       if ((linkstat & PCI_EXP_LNKSTA_CLS) == PCI_EXP_LNKSTA_CLS_2_5GB) {
>>               pcie_capability_set_word(dev, PCI_EXP_LNKCTL,
>>                                        PCI_EXP_LNKCTL_RL);
>> -             while (!altera_pcie_link_is_up(pcie)) {
>> -                     timeout++;
>> -                     if (timeout > LINK_UP_TIMEOUT)
>> -                             break;
>> -                     udelay(5);
>> -             }
>> +             altera_wait_link_retrain(dev);
>>       }
>>  }
>>  DECLARE_PCI_FIXUP_EARLY(0x1172, PCI_ANY_ID, altera_pcie_retrain);
>> --
>> 1.8.2.1
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
>> the body of a message to majordomo@vger.kernel.org
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diff mbox

Patch

diff --git a/drivers/pci/host/pcie-altera.c b/drivers/pci/host/pcie-altera.c
index 2b78376..58eef99 100644
--- a/drivers/pci/host/pcie-altera.c
+++ b/drivers/pci/host/pcie-altera.c
@@ -61,7 +61,8 @@ 
 #define TLP_LOOP			500
 #define RP_DEVFN			0
 
-#define LINK_UP_TIMEOUT			5000
+#define LINK_UP_TIMEOUT			HZ
+#define LINK_RETRAIN_TIMEOUT		HZ
 
 #define INTX_NUM			4
 
@@ -99,11 +100,44 @@  static bool altera_pcie_link_is_up(struct altera_pcie *pcie)
 	return !!((cra_readl(pcie, RP_LTSSM) & RP_LTSSM_MASK) == LTSSM_L0);
 }
 
+static void altera_wait_link_retrain(struct pci_dev *dev)
+{
+	u16 reg16;
+	unsigned long start_jiffies;
+	struct altera_pcie *pcie = dev->bus->sysdata;
+
+	/* Wait for link training end. */
+	start_jiffies = jiffies;
+	for (;;) {
+		pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &reg16);
+		if (!(reg16 & PCI_EXP_LNKSTA_LT))
+			break;
+
+		if (time_after(jiffies, start_jiffies + LINK_RETRAIN_TIMEOUT)) {
+			dev_err(&pcie->pdev->dev, "link retrain timeout\n");
+			break;
+		}
+		udelay(100);
+	}
+
+	/* Wait for link is up */
+	start_jiffies = jiffies;
+	for (;;) {
+		if (altera_pcie_link_is_up(pcie))
+			break;
+
+		if (time_after(jiffies, start_jiffies + LINK_UP_TIMEOUT)) {
+			dev_err(&pcie->pdev->dev, "link up timeout\n");
+			break;
+		}
+		udelay(100);
+	}
+}
+
 static void altera_pcie_retrain(struct pci_dev *dev)
 {
 	u16 linkcap, linkstat;
 	struct altera_pcie *pcie = dev->bus->sysdata;
-	int timeout =  0;
 
 	if (!altera_pcie_link_is_up(pcie))
 		return;
@@ -121,12 +155,7 @@  static void altera_pcie_retrain(struct pci_dev *dev)
 	if ((linkstat & PCI_EXP_LNKSTA_CLS) == PCI_EXP_LNKSTA_CLS_2_5GB) {
 		pcie_capability_set_word(dev, PCI_EXP_LNKCTL,
 					 PCI_EXP_LNKCTL_RL);
-		while (!altera_pcie_link_is_up(pcie)) {
-			timeout++;
-			if (timeout > LINK_UP_TIMEOUT)
-				break;
-			udelay(5);
-		}
+		altera_wait_link_retrain(dev);
 	}
 }
 DECLARE_PCI_FIXUP_EARLY(0x1172, PCI_ANY_ID, altera_pcie_retrain);