On 2018-07-13 19:25, Bharat Kumar Gogada wrote:
> Currently PCI_BRIDGE_CTL_SERR is being enabled only in ACPI flow.
> This bit is required for forwarding errors reported by EP devices to
> upstream device.
> This patch enables SERR# for Type-1 PCI device.
>
> Signed-off-by: Bharat Kumar Gogada <bharat.kumar.gogada@xxxxxxxxxx>
> ---
> 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..943e084 100644
> --- a/drivers/pci/pcie/aer.c
> +++ b/drivers/pci/pcie/aer.c
> @@ -343,6 +343,19 @@ int pci_enable_pcie_error_reporting(struct
> pci_dev
> *dev)
> if (!dev->aer_cap)
> return -EIO;
>
> + if (!IS_ENABLED(CONFIG_ACPI) &&
> + 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);
> + 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 +365,16 @@ int pci_disable_pcie_error_reporting(struct
> pci_dev *dev)
> if (pcie_aer_get_firmware_first(dev))
> return -EIO;
>
> + if (!IS_ENABLED(CONFIG_ACPI) &&
> + 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);
> }
Should this configuration no be set by Firmware ? why should Linux
dictate it
?
Hi Oza, Can you please let us know why this should be set by firmware ?
Spec clearly states ERR_CORR,ERR_FATAL/NON FATAL will be forwarded
only if this bit is set.
If linux AER service is being enabled without checking/setting this
bit, then AER service will
not do anything even ERR_* is seen on link.
Regards,
Bharat
The ERR_* to be forwarded or not to be forwarded could be decision of
the platform.
hence I think it is best left to firmware to decide if it want to enable
this for particular platform.
although,
There are 2 cases
Hotplug capable bridge and otherwise.
1) If Firmware sets them, I do not think during enumeraion linux will
loose those settings.
2) I do not see any integration of hotplug with AER currently, so if the
PCIe switch is plugged into Hotplug
capable RP, I am not very sure if this functions get called.
Keith, Lukas and Bjorn any comments ?
Regards,
Oza.
