diff mbox

[v15,8/9] PCI/DPC: Unify and plumb error handling into DPC

Message ID 1525323838-1735-9-git-send-email-poza@codeaurora.org (mailing list archive)
State New, archived
Delegated to: Bjorn Helgaas
Headers show

Commit Message

Oza Pawandeep May 3, 2018, 5:03 a.m. UTC 
Current DPC driver does not do recovery, e.g. calling end-point's driver's
callbacks, which sanitize the sw.

DPC driver implements link_reset callback, and calls pci_do_recovery().

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

Comments

Bjorn Helgaas May 10, 2018, 1:22 p.m. UTC | #1 
On Thu, May 03, 2018 at 01:03:57AM -0400, Oza Pawandeep wrote:
> Current DPC driver does not do recovery, e.g. calling end-point's driver's
> callbacks, which sanitize the sw.
> 
> DPC driver implements link_reset callback, and calls pci_do_recovery().
> 
> Signed-off-by: Oza Pawandeep <poza@codeaurora.org>
> 
> diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
> index 80ec384..aed7c9f 100644
> --- a/drivers/pci/pcie/dpc.c
> +++ b/drivers/pci/pcie/dpc.c
> @@ -73,29 +73,21 @@ static void dpc_wait_link_inactive(struct dpc_dev *dpc)
>  	pcie_wait_for_link(pdev, false);
>  }
>  
> -static void dpc_work(struct work_struct *work)
> +static pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
>  {
> -	struct dpc_dev *dpc = container_of(work, struct dpc_dev, work);
> -	struct pci_dev *dev, *temp, *pdev = dpc->dev->port;
> -	struct pci_bus *parent = pdev->subordinate;
> -	u16 cap = dpc->cap_pos, ctl;
> -
> -	pci_lock_rescan_remove();
> -	list_for_each_entry_safe_reverse(dev, temp, &parent->devices,
> -					 bus_list) {
> -		pci_dev_get(dev);
> -		pci_dev_set_disconnected(dev, NULL);
> -		if (pci_has_subordinate(dev))
> -			pci_walk_bus(dev->subordinate,
> -				     pci_dev_set_disconnected, NULL);
> -		pci_stop_and_remove_bus_device(dev);
> -		pci_dev_put(dev);
> -	}
> -	pci_unlock_rescan_remove();

I think it would be good to have a comment here about why this "reset_link"
function doesn't actually reset the link, e.g.,

  /*
   * DPC disables the Link automatically in hardware, so it has
   * already been reset by the time we get here.
   */

> +	struct dpc_dev *dpc;
> +	struct pcie_device *pciedev;
> +	struct device *devdpc;
> +	u16 cap, ctl;
> +
> +	devdpc = pcie_port_find_device(pdev, PCIE_PORT_SERVICE_DPC);
> +	pciedev = to_pcie_device(devdpc);
> +	dpc = get_service_data(pciedev);
> +	cap = dpc->cap_pos;

And maybe one about waiting until the link is inactive, then clearing DPC
Trigger Status to allow the port to leave DPC.

>  	dpc_wait_link_inactive(dpc);
>  	if (dpc->rp_extensions && dpc_wait_rp_inactive(dpc))
> -		return;
> +		return PCI_ERS_RESULT_DISCONNECT;
>  	if (dpc->rp_extensions && dpc->rp_pio_status) {
>  		pci_write_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_STATUS,
>  				       dpc->rp_pio_status);
> @@ -108,6 +100,17 @@ static void dpc_work(struct work_struct *work)
>  	pci_read_config_word(pdev, cap + PCI_EXP_DPC_CTL, &ctl);
>  	pci_write_config_word(pdev, cap + PCI_EXP_DPC_CTL,
>  			      ctl | PCI_EXP_DPC_CTL_INT_EN);
> +
> +	return PCI_ERS_RESULT_RECOVERED;
> +}
> +
> +static void dpc_work(struct work_struct *work)
> +{
> +	struct dpc_dev *dpc = container_of(work, struct dpc_dev, work);
> +	struct pci_dev *pdev = dpc->dev->port;
> +
> +	/* From DPC point of view error is always FATAL. */
> +	pcie_do_recovery(pdev, DPC_FATAL);
>  }
>  
>  static void dpc_process_rp_pio_error(struct dpc_dev *dpc)
> @@ -288,6 +291,7 @@ static struct pcie_port_service_driver dpcdriver = {
>  	.service	= PCIE_PORT_SERVICE_DPC,
>  	.probe		= dpc_probe,
>  	.remove		= dpc_remove,
> +	.reset_link	= dpc_reset_link,
>  };
>  
>  static int __init dpc_service_init(void)
> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
> index 877785d..526aba8 100644
> --- a/drivers/pci/pcie/err.c
> +++ b/drivers/pci/pcie/err.c
> @@ -181,11 +181,12 @@ static pci_ers_result_t default_reset_link(struct pci_dev *dev)
>  	return PCI_ERS_RESULT_RECOVERED;
>  }
>  
> -static pci_ers_result_t reset_link(struct pci_dev *dev)
> +static pci_ers_result_t reset_link(struct pci_dev *dev, int severity)
>  {
>  	struct pci_dev *udev;
>  	pci_ers_result_t status;
>  	struct pcie_port_service_driver *driver;
> +	u32 service;
>  
>  	if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
>  		/* Reset this port for all subordinates */
> @@ -196,7 +197,12 @@ static pci_ers_result_t reset_link(struct pci_dev *dev)
>  	}
>  
>  	/* Use the aer driver of the component firstly */
> -	driver = pcie_port_find_service(udev, PCIE_PORT_SERVICE_AER);
> +	if (severity == DPC_FATAL)
> +		service = PCIE_PORT_SERVICE_DPC;
> +	else
> +		service = PCIE_PORT_SERVICE_AER;
> +
> +	driver = pcie_port_find_service(udev, service);

This is where I was wondering about passing in "service" directly instead
of "severity".

>  	if (driver && driver->reset_link) {
>  		status = driver->reset_link(udev);
> @@ -302,7 +308,7 @@ static pci_ers_result_t do_fatal_recovery(struct pci_dev *dev, int severity)
>  		pci_dev_put(pdev);
>  	}
>  
> -	result = reset_link(udev);
> +	result = reset_link(udev, severity);
>  	if (result == PCI_ERS_RESULT_RECOVERED)
>  		if (pcie_wait_for_link(udev, true))
>  			pci_rescan_bus(udev->bus);
> @@ -326,7 +332,8 @@ void pcie_do_recovery(struct pci_dev *dev, int severity)
>  	pci_ers_result_t status;
>  	enum pci_channel_state state;
>  
> -	if (severity == AER_FATAL) {
> +	if ((severity == AER_FATAL) ||
> +	   (severity == DPC_FATAL)) {
>  		status = do_fatal_recovery(dev, severity);
>  		if (status != PCI_ERS_RESULT_RECOVERED)
>  			goto failed;
> diff --git a/include/linux/aer.h b/include/linux/aer.h
> index 8f87bbe..0c506fe 100644
> --- a/include/linux/aer.h
> +++ b/include/linux/aer.h
> @@ -14,6 +14,7 @@
>  #define AER_NONFATAL			0
>  #define AER_FATAL			1
>  #define AER_CORRECTABLE			2
> +#define DPC_FATAL			4
>  
>  struct pci_dev;
>  
> -- 
> 2.7.4
>
Oza Pawandeep May 10, 2018, 2:26 p.m. UTC | #2 
On 2018-05-10 18:52, Bjorn Helgaas wrote:
> On Thu, May 03, 2018 at 01:03:57AM -0400, Oza Pawandeep wrote:
>> Current DPC driver does not do recovery, e.g. calling end-point's 
>> driver's
>> callbacks, which sanitize the sw.
>> 
>> DPC driver implements link_reset callback, and calls 
>> pci_do_recovery().
>> 
>> Signed-off-by: Oza Pawandeep <poza@codeaurora.org>
>> 
>> diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
>> index 80ec384..aed7c9f 100644
>> --- a/drivers/pci/pcie/dpc.c
>> +++ b/drivers/pci/pcie/dpc.c
>> @@ -73,29 +73,21 @@ static void dpc_wait_link_inactive(struct dpc_dev 
>> *dpc)
>>  	pcie_wait_for_link(pdev, false);
>>  }
>> 
>> -static void dpc_work(struct work_struct *work)
>> +static pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
>>  {
>> -	struct dpc_dev *dpc = container_of(work, struct dpc_dev, work);
>> -	struct pci_dev *dev, *temp, *pdev = dpc->dev->port;
>> -	struct pci_bus *parent = pdev->subordinate;
>> -	u16 cap = dpc->cap_pos, ctl;
>> -
>> -	pci_lock_rescan_remove();
>> -	list_for_each_entry_safe_reverse(dev, temp, &parent->devices,
>> -					 bus_list) {
>> -		pci_dev_get(dev);
>> -		pci_dev_set_disconnected(dev, NULL);
>> -		if (pci_has_subordinate(dev))
>> -			pci_walk_bus(dev->subordinate,
>> -				     pci_dev_set_disconnected, NULL);
>> -		pci_stop_and_remove_bus_device(dev);
>> -		pci_dev_put(dev);
>> -	}
>> -	pci_unlock_rescan_remove();
> 
> I think it would be good to have a comment here about why this 
> "reset_link"
> function doesn't actually reset the link, e.g.,
> 
>   /*
>    * DPC disables the Link automatically in hardware, so it has
>    * already been reset by the time we get here.
>    */
> 
>> +	struct dpc_dev *dpc;
>> +	struct pcie_device *pciedev;
>> +	struct device *devdpc;
>> +	u16 cap, ctl;
>> +
>> +	devdpc = pcie_port_find_device(pdev, PCIE_PORT_SERVICE_DPC);
>> +	pciedev = to_pcie_device(devdpc);
>> +	dpc = get_service_data(pciedev);
>> +	cap = dpc->cap_pos;
> 
> And maybe one about waiting until the link is inactive, then clearing 
> DPC
> Trigger Status to allow the port to leave DPC.
> 
>>  	dpc_wait_link_inactive(dpc);
>>  	if (dpc->rp_extensions && dpc_wait_rp_inactive(dpc))
>> -		return;
>> +		return PCI_ERS_RESULT_DISCONNECT;
>>  	if (dpc->rp_extensions && dpc->rp_pio_status) {
>>  		pci_write_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_STATUS,
>>  				       dpc->rp_pio_status);
>> @@ -108,6 +100,17 @@ static void dpc_work(struct work_struct *work)
>>  	pci_read_config_word(pdev, cap + PCI_EXP_DPC_CTL, &ctl);
>>  	pci_write_config_word(pdev, cap + PCI_EXP_DPC_CTL,
>>  			      ctl | PCI_EXP_DPC_CTL_INT_EN);
>> +
>> +	return PCI_ERS_RESULT_RECOVERED;
>> +}
>> +
>> +static void dpc_work(struct work_struct *work)
>> +{
>> +	struct dpc_dev *dpc = container_of(work, struct dpc_dev, work);
>> +	struct pci_dev *pdev = dpc->dev->port;
>> +
>> +	/* From DPC point of view error is always FATAL. */
>> +	pcie_do_recovery(pdev, DPC_FATAL);
>>  }
>> 
>>  static void dpc_process_rp_pio_error(struct dpc_dev *dpc)
>> @@ -288,6 +291,7 @@ static struct pcie_port_service_driver dpcdriver = 
>> {
>>  	.service	= PCIE_PORT_SERVICE_DPC,
>>  	.probe		= dpc_probe,
>>  	.remove		= dpc_remove,
>> +	.reset_link	= dpc_reset_link,
>>  };
>> 
>>  static int __init dpc_service_init(void)
>> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
>> index 877785d..526aba8 100644
>> --- a/drivers/pci/pcie/err.c
>> +++ b/drivers/pci/pcie/err.c
>> @@ -181,11 +181,12 @@ static pci_ers_result_t 
>> default_reset_link(struct pci_dev *dev)
>>  	return PCI_ERS_RESULT_RECOVERED;
>>  }
>> 
>> -static pci_ers_result_t reset_link(struct pci_dev *dev)
>> +static pci_ers_result_t reset_link(struct pci_dev *dev, int severity)
>>  {
>>  	struct pci_dev *udev;
>>  	pci_ers_result_t status;
>>  	struct pcie_port_service_driver *driver;
>> +	u32 service;
>> 
>>  	if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
>>  		/* Reset this port for all subordinates */
>> @@ -196,7 +197,12 @@ static pci_ers_result_t reset_link(struct pci_dev 
>> *dev)
>>  	}
>> 
>>  	/* Use the aer driver of the component firstly */
>> -	driver = pcie_port_find_service(udev, PCIE_PORT_SERVICE_AER);
>> +	if (severity == DPC_FATAL)
>> +		service = PCIE_PORT_SERVICE_DPC;
>> +	else
>> +		service = PCIE_PORT_SERVICE_AER;
>> +
>> +	driver = pcie_port_find_service(udev, service);
> 
> This is where I was wondering about passing in "service" directly 
> instead
> of "severity".

I will take care of all your comments made on all the patches.
but this one I do not understand.

passing service directly instead of severity ? (I do not think you meant 
to write severity there)
perhaps do you mean following ?

if (severity == DPC_FATAL)
          pcie_port_find_service(udev, PCIE_PORT_SERVICE_DPC);
else
          pcie_port_find_service(udev, PCIE_PORT_SERVICE_AER);



> 
>>  	if (driver && driver->reset_link) {
>>  		status = driver->reset_link(udev);
>> @@ -302,7 +308,7 @@ static pci_ers_result_t do_fatal_recovery(struct 
>> pci_dev *dev, int severity)
>>  		pci_dev_put(pdev);
>>  	}
>> 
>> -	result = reset_link(udev);
>> +	result = reset_link(udev, severity);
>>  	if (result == PCI_ERS_RESULT_RECOVERED)
>>  		if (pcie_wait_for_link(udev, true))
>>  			pci_rescan_bus(udev->bus);
>> @@ -326,7 +332,8 @@ void pcie_do_recovery(struct pci_dev *dev, int 
>> severity)
>>  	pci_ers_result_t status;
>>  	enum pci_channel_state state;
>> 
>> -	if (severity == AER_FATAL) {
>> +	if ((severity == AER_FATAL) ||
>> +	   (severity == DPC_FATAL)) {
>>  		status = do_fatal_recovery(dev, severity);
>>  		if (status != PCI_ERS_RESULT_RECOVERED)
>>  			goto failed;
>> diff --git a/include/linux/aer.h b/include/linux/aer.h
>> index 8f87bbe..0c506fe 100644
>> --- a/include/linux/aer.h
>> +++ b/include/linux/aer.h
>> @@ -14,6 +14,7 @@
>>  #define AER_NONFATAL			0
>>  #define AER_FATAL			1
>>  #define AER_CORRECTABLE			2
>> +#define DPC_FATAL			4
>> 
>>  struct pci_dev;
>> 
>> --
>> 2.7.4
>>
Bjorn Helgaas May 10, 2018, 4:27 p.m. UTC | #3 
On Thu, May 10, 2018 at 07:56:00PM +0530, poza@codeaurora.org wrote:
> On 2018-05-10 18:52, Bjorn Helgaas wrote:
> > On Thu, May 03, 2018 at 01:03:57AM -0400, Oza Pawandeep wrote:
> ...

> > > -static pci_ers_result_t reset_link(struct pci_dev *dev)
> > > +static pci_ers_result_t reset_link(struct pci_dev *dev, int severity)
> > >  {
> > >  	struct pci_dev *udev;
> > >  	pci_ers_result_t status;
> > >  	struct pcie_port_service_driver *driver;
> > > +	u32 service;
> > > 
> > >  	if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
> > >  		/* Reset this port for all subordinates */
> > > @@ -196,7 +197,12 @@ static pci_ers_result_t reset_link(struct
> > > pci_dev *dev)
> > >  	}
> > > 
> > >  	/* Use the aer driver of the component firstly */
> > > -	driver = pcie_port_find_service(udev, PCIE_PORT_SERVICE_AER);
> > > +	if (severity == DPC_FATAL)
> > > +		service = PCIE_PORT_SERVICE_DPC;
> > > +	else
> > > +		service = PCIE_PORT_SERVICE_AER;
> > > +
> > > +	driver = pcie_port_find_service(udev, service);
> > 
> > This is where I was wondering about passing in "service" directly
> > instead
> > of "severity".
> 
> passing service directly instead of severity ? (I do not think you meant to
> write severity there)

I did mean "severity".

> perhaps do you mean following ?
> 
> if (severity == DPC_FATAL)
>          pcie_port_find_service(udev, PCIE_PORT_SERVICE_DPC);
> else
>          pcie_port_find_service(udev, PCIE_PORT_SERVICE_AER);

No, my thought was that most of the places that use "severity" only
use it to decide between PCIE_PORT_SERVICE_DPC and
PCIE_PORT_SERVICE_AER, so if you just passed in "service" directly,
you wouldn't need this "if" statement.

Bjorn
diff mbox

Patch

diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 80ec384..aed7c9f 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -73,29 +73,21 @@  static void dpc_wait_link_inactive(struct dpc_dev *dpc)
 	pcie_wait_for_link(pdev, false);
 }
 
-static void dpc_work(struct work_struct *work)
+static pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
 {
-	struct dpc_dev *dpc = container_of(work, struct dpc_dev, work);
-	struct pci_dev *dev, *temp, *pdev = dpc->dev->port;
-	struct pci_bus *parent = pdev->subordinate;
-	u16 cap = dpc->cap_pos, ctl;
-
-	pci_lock_rescan_remove();
-	list_for_each_entry_safe_reverse(dev, temp, &parent->devices,
-					 bus_list) {
-		pci_dev_get(dev);
-		pci_dev_set_disconnected(dev, NULL);
-		if (pci_has_subordinate(dev))
-			pci_walk_bus(dev->subordinate,
-				     pci_dev_set_disconnected, NULL);
-		pci_stop_and_remove_bus_device(dev);
-		pci_dev_put(dev);
-	}
-	pci_unlock_rescan_remove();
+	struct dpc_dev *dpc;
+	struct pcie_device *pciedev;
+	struct device *devdpc;
+	u16 cap, ctl;
+
+	devdpc = pcie_port_find_device(pdev, PCIE_PORT_SERVICE_DPC);
+	pciedev = to_pcie_device(devdpc);
+	dpc = get_service_data(pciedev);
+	cap = dpc->cap_pos;
 
 	dpc_wait_link_inactive(dpc);
 	if (dpc->rp_extensions && dpc_wait_rp_inactive(dpc))
-		return;
+		return PCI_ERS_RESULT_DISCONNECT;
 	if (dpc->rp_extensions && dpc->rp_pio_status) {
 		pci_write_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_STATUS,
 				       dpc->rp_pio_status);
@@ -108,6 +100,17 @@  static void dpc_work(struct work_struct *work)
 	pci_read_config_word(pdev, cap + PCI_EXP_DPC_CTL, &ctl);
 	pci_write_config_word(pdev, cap + PCI_EXP_DPC_CTL,
 			      ctl | PCI_EXP_DPC_CTL_INT_EN);
+
+	return PCI_ERS_RESULT_RECOVERED;
+}
+
+static void dpc_work(struct work_struct *work)
+{
+	struct dpc_dev *dpc = container_of(work, struct dpc_dev, work);
+	struct pci_dev *pdev = dpc->dev->port;
+
+	/* From DPC point of view error is always FATAL. */
+	pcie_do_recovery(pdev, DPC_FATAL);
 }
 
 static void dpc_process_rp_pio_error(struct dpc_dev *dpc)
@@ -288,6 +291,7 @@  static struct pcie_port_service_driver dpcdriver = {
 	.service	= PCIE_PORT_SERVICE_DPC,
 	.probe		= dpc_probe,
 	.remove		= dpc_remove,
+	.reset_link	= dpc_reset_link,
 };
 
 static int __init dpc_service_init(void)
diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index 877785d..526aba8 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -181,11 +181,12 @@  static pci_ers_result_t default_reset_link(struct pci_dev *dev)
 	return PCI_ERS_RESULT_RECOVERED;
 }
 
-static pci_ers_result_t reset_link(struct pci_dev *dev)
+static pci_ers_result_t reset_link(struct pci_dev *dev, int severity)
 {
 	struct pci_dev *udev;
 	pci_ers_result_t status;
 	struct pcie_port_service_driver *driver;
+	u32 service;
 
 	if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
 		/* Reset this port for all subordinates */
@@ -196,7 +197,12 @@  static pci_ers_result_t reset_link(struct pci_dev *dev)
 	}
 
 	/* Use the aer driver of the component firstly */
-	driver = pcie_port_find_service(udev, PCIE_PORT_SERVICE_AER);
+	if (severity == DPC_FATAL)
+		service = PCIE_PORT_SERVICE_DPC;
+	else
+		service = PCIE_PORT_SERVICE_AER;
+
+	driver = pcie_port_find_service(udev, service);
 
 	if (driver && driver->reset_link) {
 		status = driver->reset_link(udev);
@@ -302,7 +308,7 @@  static pci_ers_result_t do_fatal_recovery(struct pci_dev *dev, int severity)
 		pci_dev_put(pdev);
 	}
 
-	result = reset_link(udev);
+	result = reset_link(udev, severity);
 	if (result == PCI_ERS_RESULT_RECOVERED)
 		if (pcie_wait_for_link(udev, true))
 			pci_rescan_bus(udev->bus);
@@ -326,7 +332,8 @@  void pcie_do_recovery(struct pci_dev *dev, int severity)
 	pci_ers_result_t status;
 	enum pci_channel_state state;
 
-	if (severity == AER_FATAL) {
+	if ((severity == AER_FATAL) ||
+	   (severity == DPC_FATAL)) {
 		status = do_fatal_recovery(dev, severity);
 		if (status != PCI_ERS_RESULT_RECOVERED)
 			goto failed;
diff --git a/include/linux/aer.h b/include/linux/aer.h
index 8f87bbe..0c506fe 100644
--- a/include/linux/aer.h
+++ b/include/linux/aer.h
@@ -14,6 +14,7 @@ 
 #define AER_NONFATAL			0
 #define AER_FATAL			1
 #define AER_CORRECTABLE			2
+#define DPC_FATAL			4
 
 struct pci_dev;