lkml.org 
[lkml]   [2018]   [Sep]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2] PCI/AER: Enable SERR# forwarding in non ACPI flow
On 2018-09-06 01:40, Bjorn Helgaas wrote:
> On Thu, Aug 09, 2018 at 08:41:27PM +0530, poza@codeaurora.org wrote:
>> On 2018-08-09 20:27, Bharat Kumar Gogada wrote:
>> > As per Figure 6-3 in PCIe r4.0, sec 6.2.6, ERR_ messages
>> > will be forwarded from the secondary interface to the primary interface,
>> > if the SERR# Enable bit in the Bridge Control register is set.
>> > Currently PCI_BRIDGE_CTL_SERR is being enabled only in
>> > ACPI flow.
>> > This patch enables PCI_BRIDGE_CTL_SERR for Type-1 PCI device.
>> >
>> > Signed-off-by: Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com>
>> > ---
>> > drivers/pci/pcie/aer.c | 23 +++++++++++++++++++++++
>> > 1 files changed, 23 insertions(+), 0 deletions(-)
>> >
>> > diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
>> > index a2e8838..4fb0d24 100644
>> > --- a/drivers/pci/pcie/aer.c
>> > +++ b/drivers/pci/pcie/aer.c
>> > @@ -343,6 +343,20 @@ int pci_enable_pcie_error_reporting(struct pci_dev
>> > *dev)
>> > if (!dev->aer_cap)
>> > return -EIO;
>> >
>> > + if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
>> > + u16 control;
>> > +
>> > + /*
>> > + * A Type-1 PCI bridge will not forward ERR_ messages coming
>> > + * from an endpoint if SERR# forwarding is not enabled.
>> > + */
>> > + pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &control);
>> > + if (!(control & PCI_BRIDGE_CTL_SERR)) {
>> > + control |= PCI_BRIDGE_CTL_SERR;
>> > + pci_write_config_word(dev, PCI_BRIDGE_CONTROL, control);
>> > + }
>> > + }
>> > +
>> > return pcie_capability_set_word(dev, PCI_EXP_DEVCTL,
>> > PCI_EXP_AER_FLAGS);
>> > }
>> > EXPORT_SYMBOL_GPL(pci_enable_pcie_error_reporting);
>> > @@ -352,6 +366,15 @@ int pci_disable_pcie_error_reporting(struct pci_dev
>> > *dev)
>> > if (pcie_aer_get_firmware_first(dev))
>> > return -EIO;
>> >
>> > + if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
>> > + u16 control;
>> > +
>> > + /* Clear SERR Forwarding */
>> > + pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &control);
>> > + control &= ~PCI_BRIDGE_CTL_SERR;
>> > + pci_write_config_word(dev, PCI_BRIDGE_CONTROL, control);
>> > + }
>> > +
>> > return pcie_capability_clear_word(dev, PCI_EXP_DEVCTL,
>> > PCI_EXP_AER_FLAGS);
>> > }
>>
>>
>> Hi Bjorn,
>>
>> I made some comments on patchv1., same I am putting it across here.
>>
>> what about hot-plug case ?
>> should not aer_init() call pci_enable_pcie_error_reporting() for all
>> the downstream pci_dev ?
>> and remove all the calls from drivers..
>> aer_init will be called for each device (pci_dev) while pciehp does
>> re-enumeration.
>> so probable we might want to call pci_enable_pcie_error_reporting()
>> but that dictates the design where AER framework is taking decision to
>> enable error reporting on behalf of drivers as well.
>> but thats fine I think, if drivers do not want to participate then
>> they have
>> to call pci_disable_pcie_error_reporting explicitly.
>> does this make sense ?
>
> I just replied to the original patch; sorry, I forgot to add you to
> the cc list. Bharat, when people respond to your v<N> patch, can you
> please add them (and anybody else *they* added) to the cc list when
> you post your v<N+1> patch?
>
> If we set PCI_BRIDGE_CTL_SERR in the pci_configure_device() path,
> would that address your comments?

yes, that should do.

>
> There's still a separate question of where and how we should configure
> the error bits in PCI_EXP_DEVCTL (currently done in
> pci_enable_pcie_error_reporting()).
>
> Bjorn

\
 
 \ /
  Last update: 2018-09-10 08:10    [W:0.121 / U:0.076 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site