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Message-ID: <20201205213038.GA2093063@bjorn-Precision-5520>
Date: Sat, 5 Dec 2020 15:30:38 -0600
From: Bjorn Helgaas <helgaas@...nel.org>
To: "Kelley, Sean V" <sean.v.kelley@...el.com>
Cc: "bhelgaas@...gle.com" <bhelgaas@...gle.com>,
Jonathan Cameron <Jonathan.Cameron@...wei.com>,
"xerces.zhao@...il.com" <xerces.zhao@...il.com>,
"Wysocki, Rafael J" <rafael.j.wysocki@...el.com>,
"Raj, Ashok" <ashok.raj@...el.com>,
"Luck, Tony" <tony.luck@...el.com>,
"Kuppuswamy, Sathyanarayanan" <sathyanarayanan.kuppuswamy@...el.com>,
"Zhuo, Qiuxu" <qiuxu.zhuo@...el.com>,
Linux PCI <linux-pci@...r.kernel.org>,
Linux List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v12 12/15] PCI/RCEC: Add RCiEP's linked RCEC to AER/ERR
On Fri, Dec 04, 2020 at 05:17:58PM +0000, Kelley, Sean V wrote:
> > On Dec 3, 2020, at 4:01 PM, Bjorn Helgaas <helgaas@...nel.org> wrote:
> > On Thu, Dec 03, 2020 at 12:51:40AM +0000, Kelley, Sean V wrote:
> >>> On Dec 2, 2020, at 3:44 PM, Bjorn Helgaas <helgaas@...nel.org> wrote:
> >>> On Fri, Nov 20, 2020 at 04:10:33PM -0800, Sean V Kelley wrote:
> >>>> From: Qiuxu Zhuo <qiuxu.zhuo@...el.com>
> >>>>
> >>>> When attempting error recovery for an RCiEP associated with an RCEC device,
> >>>> there needs to be a way to update the Root Error Status, the Uncorrectable
> >>>> Error Status and the Uncorrectable Error Severity of the parent RCEC. In
> >>>> some non-native cases in which there is no OS-visible device associated
> >>>> with the RCiEP, there is nothing to act upon as the firmware is acting
> >>>> before the OS.
> >>>>
> >>>> Add handling for the linked RCEC in AER/ERR while taking into account
> >>>> non-native cases.
> >>>>
> >>>> Co-developed-by: Sean V Kelley <sean.v.kelley@...el.com>
> >>>> Link: https://lore.kernel.org/r/20201002184735.1229220-12-seanvk.dev@oregontracks.org
> >>>> Signed-off-by: Sean V Kelley <sean.v.kelley@...el.com>
> >>>> Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@...el.com>
> >>>> Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
> >>>> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
> >>>> ---
> >>>> drivers/pci/pcie/aer.c | 46 +++++++++++++++++++++++++++++++-----------
> >>>> drivers/pci/pcie/err.c | 20 +++++++++---------
> >>>> 2 files changed, 44 insertions(+), 22 deletions(-)
> >>>>
> >>>> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> >>>> index 0ba0b47ae751..51389a6ee4ca 100644
> >>>> --- a/drivers/pci/pcie/aer.c
> >>>> +++ b/drivers/pci/pcie/aer.c
> >>>> @@ -1358,29 +1358,51 @@ static int aer_probe(struct pcie_device *dev)
> >>>> */
> >>>> static pci_ers_result_t aer_root_reset(struct pci_dev *dev)
> >>>> {
> >>>> - int aer = dev->aer_cap;
> >>>> + int type = pci_pcie_type(dev);
> >>>> + struct pci_dev *root;
> >>>> + int aer = 0;
> >>>> + int rc = 0;
> >>>> u32 reg32;
> >>>> - int rc;
> >>>>
> >>>> - if (pcie_aer_is_native(dev)) {
> >>>> + if (type == PCI_EXP_TYPE_RC_END)
> >>>> + /*
> >>>> + * The reset should only clear the Root Error Status
> >>>> + * of the RCEC. Only perform this for the
> >>>> + * native case, i.e., an RCEC is present.
> >>>> + */
> >>>> + root = dev->rcec;
> >>>> + else
> >>>> + root = dev;
> >>>> +
> >>>> + if (root)
> >>>> + aer = dev->aer_cap;
> >>>> +
> >>>> + if ((aer) && pcie_aer_is_native(dev)) {
> >>>> /* Disable Root's interrupt in response to error messages */
> >>>> - pci_read_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, ®32);
> >>>> + pci_read_config_dword(root, aer + PCI_ERR_ROOT_COMMAND, ®32);
> >>>> reg32 &= ~ROOT_PORT_INTR_ON_MESG_MASK;
> >>>> - pci_write_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, reg32);
> >>>> + pci_write_config_dword(root, aer + PCI_ERR_ROOT_COMMAND, reg32);
> >>>> }
> >>>>
> >>>> - rc = pci_bus_error_reset(dev);
> >>>> - pci_info(dev, "Root Port link has been reset (%d)\n", rc);
> >>>> + if (type == PCI_EXP_TYPE_RC_EC || type == PCI_EXP_TYPE_RC_END) {
> >>>> + if (pcie_has_flr(dev)) {
> >>>> + rc = pcie_flr(dev);
> >>>> + pci_info(dev, "has been reset (%d)\n", rc);
> >>>
> >>> Maybe:
> >>>
> >>> + } else {
> >>> + rc = -ENOTTY;
> >>> + pci_info(dev, "not reset (no FLR support)\n");
> >>>
> >>> Or do we want to pretend the device was reset and return
> >>> PCI_ERS_RESULT_RECOVERED?
> >>
> >> We are currently doing the latter now with the default of rc = 0
> >> above and so I’m not sure the extra detail here on the absence of
> >> FLR support is of value.
> >
> > So to make sure I understand the proposal here, for RCECs and RCiEPs
> > that don't support FLR, you're saying you want to continue silently
> > and return PCI_ERS_RESULT_RECOVERED and let the drivers assume their
> > device was reset when it was not?
>
> The setting of the ‘rc’ on the FLR support is fine to add to the
> else condition. I had simply recalled in earlier discussion that
> pcie_has_flr() was needed due to quirky behavior in some hardware
> and so was not sure that detail of having or not having flr was in
> fact consitent/accurate.
I think we should do the following, unless you object:
if (type == PCI_EXP_TYPE_RC_EC || type == PCI_EXP_TYPE_RC_END) {
if (pcie_has_flr(dev)) {
rc = pcie_flr(dev);
pci_info(dev, "has been reset (%d)\n", rc);
} else {
pci_info(dev, "not reset (no FLR support)\n");
rc = -ENOTTY;
}
} else {
rc = pci_bus_error_reset(dev);
pci_info(dev, "Root Port link has been reset (%d)\n", rc);
}
...
return rc ? PCI_ERS_RESULT_DISCONNECT : PCI_ERS_RESULT_RECOVERED;
Sorry, I should have done that in the proposed patch earlier; it's
what I was *thinking* but didn't get it transcribed into the code.
Bjorn
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