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Date:   Tue, 27 Feb 2018 11:36:25 +0530
From:   poza@codeaurora.org
To:     Bjorn Helgaas <helgaas@kernel.org>
Cc:     Bjorn Helgaas <bhelgaas@google.com>,
        Philippe Ombredanne <pombredanne@nexb.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Kate Stewart <kstewart@linuxfoundation.org>,
        linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
        Dongdong Liu <liudongdong3@huawei.com>,
        Keith Busch <keith.busch@intel.com>, Wei Zhang <wzhang@fb.com>,
        Sinan Kaya <okaya@codeaurora.org>,
        Timur Tabi <timur@codeaurora.org>
Subject: Re: [PATCH v11 4/7] PCI/DPC: Unify and plumb error handling into DPC
In-Reply-To: <20180224000754.GR14632@bhelgaas-glaptop.roam.corp.google.com>
References: <1519374244-20539-1-git-send-email-poza@codeaurora.org>
 <1519374244-20539-5-git-send-email-poza@codeaurora.org>
 <20180224000754.GR14632@bhelgaas-glaptop.roam.corp.google.com>
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On 2018-02-24 05:37, Bjorn Helgaas wrote:
> On Fri, Feb 23, 2018 at 01:54:01PM +0530, 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 pcie_do_recovery.
> 
> s/pcie_do_recovery/pcie_do_recovery()/
> 

sure.

>> Signed-off-by: Oza Pawandeep <poza@codeaurora.org>
>> 
>> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
>> index abc514e..f8575da 100644
>> --- a/drivers/pci/pci.h
>> +++ b/drivers/pci/pci.h
>> @@ -343,6 +343,8 @@ static inline resource_size_t 
>> pci_resource_alignment(struct pci_dev *dev,
>>  void pci_enable_acs(struct pci_dev *dev);
>> 
>>  /* PCI error reporting and recovery */
>> +#define DPC_FATAL	4
> 
> This needs to go next to the AER_FATAL, etc., definitions because
> DPC_FATAL shares the namespace and they all need to have distinct
> values.  I can't tell from this patch whether they do or not.
> 

sure.

>>  void pcie_do_recovery(struct pci_dev *dev, int severity);
>> 
>>  #ifdef CONFIG_PCIEASPM
>> diff --git a/drivers/pci/pcie/pcie-dpc.c b/drivers/pci/pcie/pcie-dpc.c
>> index 38e40c6..5c01c63 100644
>> --- a/drivers/pci/pcie/pcie-dpc.c
>> +++ b/drivers/pci/pcie/pcie-dpc.c
>> @@ -13,6 +13,7 @@
>>  #include <linux/pcieport_if.h>
>>  #include "../pci.h"
>>  #include "aer/aerdrv.h"
>> +#include "portdrv.h"
>> 
>>  struct dpc_dev {
>>  	struct pcie_device	*dev;
>> @@ -45,6 +46,58 @@ struct dpc_dev {
>>  	"Memory Request Completion Timeout",		 /* Bit Position 18 */
>>  };
>> 
>> +static int find_dpc_dev_iter(struct device *device, void *data)
>> +{
>> +	struct pcie_port_service_driver *service_driver;
>> +	struct device **dev = (struct device **) data;;
>> +
>> +	if (device->bus == &pcie_port_bus_type && device->driver) {
>> +		service_driver = to_service_driver(device->driver);
>> +		if (service_driver->service == PCIE_PORT_SERVICE_DPC) {
>> +			*dev = device;
>> +			return 1;
>> +		}
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static struct device *pci_find_dpc_dev(struct pci_dev *pdev)
>> +{
>> +	struct device *dev = NULL;
>> +
>> +	device_for_each_child(&pdev->dev, &dev, find_dpc_dev_iter);
>> +
>> +	return dev;
>> +}
> 
> Ugh.  You're not responsible for this and you don't need to do
> anything, but hanging the struct dpc_dev off the struct pcie_device
> and then having to grub around like this to locate it from the pci_dev
> is just ... clunky.  OK, rant over, sorry :)
> 

:) I keep it for now.

>> +static int find_dpc_service_iter(struct device *device, void *data)
>> +{
>> +	struct pcie_port_service_driver *service_driver;
>> +	struct pcie_port_service_driver **drv =
>> +		(struct pcie_port_service_driver **) data;
>> +
>> +	if (device->bus == &pcie_port_bus_type && device->driver) {
>> +		service_driver = to_service_driver(device->driver);
>> +		if (service_driver->service == PCIE_PORT_SERVICE_DPC) {
>> +			*drv = service_driver;
>> +			return 1;
>> +		}
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +struct pcie_port_service_driver *pci_find_dpc_service(struct pci_dev 
>> *dev)
>> +{
>> +	struct pcie_port_service_driver *drv = NULL;
>> +
>> +	device_for_each_child(&dev->dev, &drv, find_dpc_service_iter);
>> +
>> +	return drv;
>> +}
>> +EXPORT_SYMBOL_GPL(pci_find_dpc_service);
> 
> No module uses this, so it doesn't need to be exported.
> 
> This is a clone of find_aer_service().  Can you add a preliminary patch 
> to
> make a generic "find service" interface that accepts the service type
> (PCIE_PORT_SERVICE_AER, PCIE_PORT_SERVICE_DPC) as a parameter?
> 
> This whole "find service" thing is ugly as sin.  You're not responsible 
> for
> cleaning it up, but maybe we can at least limit the proliferation of 
> it.
> 

I have taken care of making this as a generic find_Service in pcie port 
driver now.

>>  static int dpc_wait_rp_inactive(struct dpc_dev *dpc)
>>  {
>>  	unsigned long timeout = jiffies + HZ;
>> @@ -82,12 +135,25 @@ static void dpc_wait_link_inactive(struct dpc_dev 
>> *dpc)
>>  		dev_warn(dev, "Link state not disabled for DPC event\n");
>>  }
>> 
>> -static void dpc_work(struct work_struct *work)
>> +/**
>> + * dpc_reset_link - reset link DPC  routine
> 
> s/  / / (remove extra space)
sure.
> 
>> + * @dev: pointer to Root Port's pci_dev data structure
>> + *
>> + * Invoked by Port Bus driver when performing link reset at Root 
>> Port.
>> + */
>> +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;
>> +	struct pci_dev *dev, *temp;
>> +	struct dpc_dev *dpc;
>> +	struct pcie_device *pciedev;
>> +	struct device *devdpc;
>> +	u16 cap, ctl;
>> +
>> +	devdpc = pci_find_dpc_dev(pdev);
>> +	pciedev = to_pcie_device(devdpc);
>> +	dpc = get_service_data(pciedev);
>> +	cap = dpc->cap_pos;
>> 
>>  	pci_lock_rescan_remove();
>>  	list_for_each_entry_safe_reverse(dev, temp, &parent->devices,
>> @@ -104,21 +170,31 @@ static void dpc_work(struct work_struct *work)
>> 
>>  	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);
>>  		dpc->rp_pio_status = 0;
>>  	}
>> 
>> -	pci_write_config_word(pdev, cap + PCI_EXP_DPC_STATUS,
>> +	pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_STATUS,
>>  		PCI_EXP_DPC_STATUS_TRIGGER | PCI_EXP_DPC_STATUS_INTERRUPT);
>> 
>>  	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);
>> +				ctl | PCI_EXP_DPC_CTL_INT_EN);
> 
> Align "ctl" with "pdev".

sure.
> 
>> +	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)
>>  {
>>  	struct device *dev = &dpc->dev->device;
>> @@ -297,6 +373,7 @@ static void dpc_remove(struct pcie_device *dev)
>>  	.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/pcie-err.c b/drivers/pci/pcie/pcie-err.c
>> index f830975..1ea4b9a 100644
>> --- a/drivers/pci/pcie/pcie-err.c
>> +++ b/drivers/pci/pcie/pcie-err.c
>> @@ -19,6 +19,7 @@
>>  #include <linux/aer.h>
>>  #include <linux/pcieport_if.h>
>>  #include "portdrv.h"
>> +#include "./../pci.h"
>> 
>>  static DEFINE_MUTEX(pci_err_recovery_lock);
>> 
>> @@ -181,7 +182,7 @@ 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;
>> @@ -195,9 +196,17 @@ static pci_ers_result_t reset_link(struct pci_dev 
>> *dev)
>>  		udev = dev->bus->self;
>>  	}
>> 
>> +
>> +	/* Use the service driver of the component firstly */
>> +#if IS_ENABLED(CONFIG_PCIE_DPC)
> 
> #ifdef CONFIG_PCIE_DPC
> 
>> +	if (severity == DPC_FATAL)
>> +		driver = pci_find_dpc_service(udev);
>> +#endif
>>  #if IS_ENABLED(CONFIG_PCIEAER)
>> -	/* Use the aer driver of the component firstly */
>> -	driver = pci_find_aer_service(udev);
>> +	if (severity == AER_FATAL ||
>> +	    severity == AER_NONFATAL ||
>> +	    severity == AER_CORRECTABLE)
> 
> This change (to check for AER_FATAL, etc) looks like it belongs in a
> different patch.  This patch doesn't change any places that set the
> severity.

I have made generic service and probably now it does not look like this.

> 
>> +		driver = pci_find_aer_service(udev);
>>  #endif
>> 
>>  	if (driver && driver->reset_link) {
>> @@ -287,7 +296,8 @@ void pcie_do_recovery(struct pci_dev *dev, int 
>> severity)
>> 
>>  	mutex_lock(&pci_err_recovery_lock);
>> 
>> -	if (severity == AER_FATAL)
>> +	if (severity == AER_FATAL ||
>> +	    severity == DPC_FATAL)
>>  		state = pci_channel_io_frozen;
>>  	else
>>  		state = pci_channel_io_normal;
>> @@ -297,10 +307,14 @@ void pcie_do_recovery(struct pci_dev *dev, int 
>> severity)
>>  			"error_detected",
>>  			report_error_detected);
>> 
>> -	if (severity == AER_FATAL) {
>> -		result = reset_link(dev);
>> +	if (severity == AER_FATAL ||
>> +	    severity == DPC_FATAL) {
>> +		result = reset_link(dev, severity);
>>  		if (result != PCI_ERS_RESULT_RECOVERED)
>>  			goto failed;
>> +		else if (severity == DPC_FATAL)
>> +			goto resume;
>> +
>>  	}
>> 
>>  	if (status == PCI_ERS_RESULT_CAN_RECOVER)
>> @@ -324,6 +338,7 @@ void pcie_do_recovery(struct pci_dev *dev, int 
>> severity)
>>  	if (status != PCI_ERS_RESULT_RECOVERED)
>>  		goto failed;
>> 
>> +resume:
>>  	broadcast_error_message(dev,
>>  				state,
>>  				"resume",
>> diff --git a/drivers/pci/pcie/portdrv.h b/drivers/pci/pcie/portdrv.h
>> index 4f1992d..b013e24 100644
>> --- a/drivers/pci/pcie/portdrv.h
>> +++ b/drivers/pci/pcie/portdrv.h
>> @@ -80,4 +80,5 @@ static inline void pcie_port_platform_notify(struct 
>> pci_dev *port, int *mask){}
>>  #endif /* !CONFIG_ACPI */
>> 
>>  struct pcie_port_service_driver *pci_find_aer_service(struct pci_dev 
>> *dev);
>> +struct pcie_port_service_driver *pci_find_dpc_service(struct pci_dev 
>> *dev);
>>  #endif /* _PORTDRV_H_ */
>> --
>> Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm 
>> Technologies, Inc.,
>> a Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a 
>> Linux Foundation Collaborative Project.
>>