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From: "Sean V Kelley" <sean.v.kelley@intel.com>
To: "Jonathan Cameron" <Jonathan.Cameron@Huawei.com>
Cc: bhelgaas@google.com, rjw@rjwysocki.net, tony.luck@intel.com,
	"Raj, Ashok" <ashok.raj@intel.com>,
	sathyanarayanan.kuppuswamy@linux.intel.com,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
	"Qiuxu Zhuo" <qiuxu.zhuo@intel.com>
Subject: Re: [RFC PATCH 7/9] PCI/AER: Add RCEC AER handling
Date: Mon, 27 Jul 2020 08:19:39 -0700
Message-ID: <6C5C96C5-0365-48A0-B623-1A4C0CE0D13E@intel.com> (raw)
In-Reply-To: <20200727132252.0000644c@Huawei.com>

On 27 Jul 2020, at 5:22, Jonathan Cameron wrote:

> On Fri, 24 Jul 2020 10:22:21 -0700
> Sean V Kelley <sean.v.kelley@intel.com> wrote:
>
>> The Root Complex Event Collectors(RCEC) appear as peers to Root Ports
>> and also have the AER capability. So add RCEC support to the current 
>> AER
>> service driver and attach the AER service driver to the RCEC device.
>>
>> Co-developed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
>> Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
>> Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
>
> A few questions and comments for this patch.
>
> See inline.
>
> Jonathan
>
>
>> ---
>>  drivers/pci/pcie/aer.c | 34 +++++++++++++++++++++++++++-------
>>  1 file changed, 27 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
>> index f1bf06be449e..7cc430c74c46 100644
>> --- a/drivers/pci/pcie/aer.c
>> +++ b/drivers/pci/pcie/aer.c
>> @@ -303,7 +303,7 @@ int pci_aer_raw_clear_status(struct pci_dev *dev)
>>  		return -EIO;
>>
>>  	port_type = pci_pcie_type(dev);
>> -	if (port_type == PCI_EXP_TYPE_ROOT_PORT) {
>> +	if (port_type == PCI_EXP_TYPE_ROOT_PORT || port_type == 
>> PCI_EXP_TYPE_RC_EC) {
>>  		pci_read_config_dword(dev, aer + PCI_ERR_ROOT_STATUS, &status);
>>  		pci_write_config_dword(dev, aer + PCI_ERR_ROOT_STATUS, status);
>>  	}
>> @@ -389,6 +389,12 @@ void pci_aer_init(struct pci_dev *dev)
>>  	pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_ERR, sizeof(u32) * 
>> n);
>>
>>  	pci_aer_clear_status(dev);
>> +
>> +	if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_EC) {
>> +		if (!pci_find_ext_capability(dev, PCI_EXT_CAP_ID_RCEC))
>> +			return;
>> +		pci_info(dev, "AER: RCEC CAP FOUND and cap_has_rtctl = %d\n", n);
>
> It feels like failing to find an RC_EC extended cap in a RCEC deserved
> a nice strong error message.  Perhaps this isn't the right place to do 
> it
> though.  For that matter, why are we checking for it here?

Sorry, I’ve left an in-development output in the code.  Will replace 
with a check with more meaningful output elsewhere.

>
>> +	}
>>  }
>>
>>  void pci_aer_exit(struct pci_dev *dev)
>> @@ -577,7 +583,8 @@ static umode_t aer_stats_attrs_are_visible(struct 
>> kobject *kobj,
>>  	if ((a == &dev_attr_aer_rootport_total_err_cor.attr ||
>>  	     a == &dev_attr_aer_rootport_total_err_fatal.attr ||
>>  	     a == &dev_attr_aer_rootport_total_err_nonfatal.attr) &&
>
> It is a bit ugly to have these called rootport_total_err etc for the 
> rcec.
> Perhaps we should just add additional attributes to reflect we are 
> looking at
> an RCEC?

I was trying to avoid any renaming to reduce churn as I did with my 
first patch for ACPI / CLX_OSC support.
Will take a look.

>
>> -	    pci_pcie_type(pdev) != PCI_EXP_TYPE_ROOT_PORT)
>> +	    ((pci_pcie_type(pdev) != PCI_EXP_TYPE_ROOT_PORT) &&
>> +	    (pci_pcie_type(pdev) != PCI_EXP_TYPE_RC_EC)))
>>  		return 0;
>>
>>  	return a->mode;
>> @@ -894,7 +901,10 @@ static bool find_source_device(struct pci_dev 
>> *parent,
>>  	if (result)
>>  		return true;
>>
>> -	pci_walk_bus(parent->subordinate, find_device_iter, e_info);
>> +	if (pci_pcie_type(parent) == PCI_EXP_TYPE_RC_EC)
>> +		pcie_walk_rcec(parent, find_device_iter, e_info);
>> +	else
>> +		pci_walk_bus(parent->subordinate, find_device_iter, e_info);
>>
>>  	if (!e_info->error_dev_num) {
>>  		pci_info(parent, "can't find device of ID%04x\n", e_info->id);
>> @@ -1030,6 +1040,7 @@ int aer_get_device_error_info(struct pci_dev 
>> *dev, struct aer_err_info *info)
>>  		if (!(info->status & ~info->mask))
>>  			return 0;
>>  	} else if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
>> +		   pci_pcie_type(dev) == PCI_EXP_TYPE_RC_EC ||
>>  	           pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM ||
>>  		   info->severity == AER_NONFATAL) {
>>
>> @@ -1182,6 +1193,8 @@ static int set_device_error_reporting(struct 
>> pci_dev *dev, void *data)
>>  	int type = pci_pcie_type(dev);
>>
>>  	if ((type == PCI_EXP_TYPE_ROOT_PORT) ||
>> +	    (type == PCI_EXP_TYPE_RC_EC) ||
>> +	    (type == PCI_EXP_TYPE_RC_END) ||
>
> Why add RC_END here?

I’m not clear on your question.  Errors can come from RCEC or RCiEPs.  
We still need to enable reporting by the RCiEPs.

>
>>  	    (type == PCI_EXP_TYPE_UPSTREAM) ||
>>  	    (type == PCI_EXP_TYPE_DOWNSTREAM)) {
>>  		if (enable)
>> @@ -1206,9 +1219,11 @@ static void 
>> set_downstream_devices_error_reporting(struct pci_dev *dev,
>>  {
>>  	set_device_error_reporting(dev, &enable);
>>
>> -	if (!dev->subordinate)
>> -		return;
>> -	pci_walk_bus(dev->subordinate, set_device_error_reporting, 
>> &enable);
>> +	if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_EC)
>> +		pcie_walk_rcec(dev, set_device_error_reporting, &enable);
>> +	else if (dev->subordinate)
>> +		pci_walk_bus(dev->subordinate, set_device_error_reporting, 
>> &enable);
>> +
>>  }
>>
>>  /**
>> @@ -1306,6 +1321,11 @@ static int aer_probe(struct pcie_device *dev)
>>  	struct device *device = &dev->device;
>>  	struct pci_dev *port = dev->port;
>>
>> +	/* Limit to Root Ports or Root Complex Event Collectors */
>> +	if ((pci_pcie_type(port) != PCI_EXP_TYPE_RC_EC) &&
>> +	    (pci_pcie_type(port) != PCI_EXP_TYPE_ROOT_PORT))
>> +		return -ENODEV;
>> +
>>  	rpc = devm_kzalloc(device, sizeof(struct aer_rpc), GFP_KERNEL);
>>  	if (!rpc)
>>  		return -ENOMEM;
>> @@ -1362,7 +1382,7 @@ static pci_ers_result_t aer_root_reset(struct 
>> pci_dev *dev)
>>
>>  static struct pcie_port_service_driver aerdriver = {
>>  	.name		= "aer",
>> -	.port_type	= PCI_EXP_TYPE_ROOT_PORT,
>> +	.port_type	= PCIE_ANY_PORT,
>
> Why this particular change?  Seems that is a lot wider than simply
> adding RCEC.  Obviously we'll then drop out in the aer_probe but it
> is still rather inelegant.

In order to extend the service drivers to non-root-port devices (i.e., 
RCEC), the simple path appeared to only require setting the type to 
ANY_PORT and catching the needed types arriving in the probe.  Would you 
prefer extending to a type2?  I’m not sure how one is more elegant 
than another but open to that approach.  However, this seems to require 
less code perhaps and seems consistent with most ‘drop-out’ 
conditional patterns in the kernel.  The same applies to pme.

Thanks,

Sean


>
>>  	.service	= PCIE_PORT_SERVICE_AER,
>>
>>  	.probe		= aer_probe,

  reply index

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-24 17:22 [RFC PATCH 0/9] Add RCEC handling to PCI/AER Sean V Kelley
2020-07-24 17:22 ` [RFC PATCH 1/9] pci_ids: Add class code and extended capability for RCEC Sean V Kelley
2020-07-27 10:00   ` Jonathan Cameron
2020-07-27 10:21     ` Jonathan Cameron
2020-07-27 15:22       ` Sean V Kelley
2020-07-24 17:22 ` [RFC PATCH 2/9] PCI: Extend Root Port Driver to support RCEC Sean V Kelley
2020-07-27 12:30   ` Jonathan Cameron
2020-07-27 15:05     ` Sean V Kelley
2020-07-24 17:22 ` [RFC PATCH 3/9] PCI/portdrv: Add pcie_walk_rcec() to walk RCiEPs associated with RCEC Sean V Kelley
2020-07-27 10:49   ` Jonathan Cameron
2020-07-27 15:21     ` Sean V Kelley
2020-07-24 17:22 ` [RFC PATCH 4/9] PCI/AER: Extend AER error handling to RCECs Sean V Kelley
2020-07-27 11:00   ` Jonathan Cameron
2020-07-27 14:58     ` Sean V Kelley
2020-07-27 14:04   ` Jonathan Cameron
2020-07-27 15:00     ` Sean V Kelley
2020-07-24 17:22 ` [RFC PATCH 5/9] PCI/AER: Apply function level reset to RCiEP on fatal error Sean V Kelley
2020-07-27 11:17   ` Jonathan Cameron
2020-07-28 13:27     ` Zhuo, Qiuxu
2020-07-28 16:14       ` Sean V Kelley
2020-07-28 17:02         ` Jonathan Cameron
2020-07-28 17:42           ` Sean V Kelley
2020-07-24 17:22 ` [RFC PATCH 6/9] PCI: Add 'rcec' field to pci_dev for associated RCiEPs Sean V Kelley
2020-07-27 11:23   ` Jonathan Cameron
2020-07-27 15:39     ` Sean V Kelley
2020-07-27 16:11     ` Jonathan Cameron
2020-07-27 16:28       ` Sean V Kelley
2020-07-24 17:22 ` [RFC PATCH 7/9] PCI/AER: Add RCEC AER handling Sean V Kelley
2020-07-27 12:22   ` Jonathan Cameron
2020-07-27 15:19     ` Sean V Kelley [this message]
2020-07-27 17:14       ` Jonathan Cameron
2020-07-24 17:22 ` [RFC PATCH 8/9] PCI/PME: Add RCEC PME handling Sean V Kelley
2020-08-04  8:35   ` Jay Fang
2020-08-04  9:47     ` Jonathan Cameron
2020-07-24 17:22 ` [RFC PATCH 9/9] PCI/AER: Add RCEC AER error injection support Sean V Kelley
2020-07-27 12:37 ` [RFC PATCH 0/9] Add RCEC handling to PCI/AER Jonathan Cameron
2020-07-27 14:56   ` Sean V Kelley

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