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PCI: aerdrv: introduce default_downstream_reset_link

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I noticed that when I inject a fatal error to an endpoint via
aer-inject, aer_root_reset() is called as reset_link for a
downstream port at upstream of the endpoint:

  pcieport 0000:00:06.0: AER: Uncorrected (Fatal) error received: id=5401
   :
  pcieport 0000:52:02.0: Root Port link has been reset

It externally appears to be working, but internally issues some
accesses to PCI_ERR_ROOT_COMMAND/STATUS registers that is for
root port so not available on downstream port.

This patch introduces default_downstream_reset_link that is
a version of aer_root_reset() with no accesses to root port's
register. It is used for downstream ports that has no reset_link
function its specific.

This patch also updates related description in pcieaer-howto.txt.
Some minor fixes are included.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This commit is contained in:
Hidetoshi Seto
2010-04-15 13:21:27 +09:00
committed by Jesse Barnes
parent 517cae3829
commit 89713422a7
4 changed files with 71 additions and 46 deletions
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15
Documentation/PCI/pcieaer-howto.txt
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@@ -13,7 +13,7 @@ Reporting (AER) driver and provides information on how to use it, as
well as how to enable the drivers of endpoint devices to conform with
PCI Express AER driver.
1.2 Copyright <EFBFBD> Intel Corporation 2006.
1.2 Copyright (C) Intel Corporation 2006.
1.3 What is the PCI Express AER Driver?
@@ -108,7 +108,7 @@ but the PCI Express link itself is fully functional. Fatal errors, on
the other hand, cause the link to be unreliable.
When AER is enabled, a PCI Express device will automatically send an
error message to the PCIE root port above it when the device captures
error message to the PCIe root port above it when the device captures
an error. The Root Port, upon receiving an error reporting message,
internally processes and logs the error message in its PCI Express
capability structure. Error information being logged includes storing
@@ -194,8 +194,9 @@ to reset link, AER port service driver is required to provide the
function to reset link. Firstly, kernel looks for if the upstream
component has an aer driver. If it has, kernel uses the reset_link
callback of the aer driver. If the upstream component has no aer driver
and the port is downstream port, we will use the aer driver of the
root port who reports the AER error. As for upstream ports,
and the port is downstream port, we will perform a hot reset as the
default by setting the Secondary Bus Reset bit of the Bridge Control
register associated with the downstream port. As for upstream ports,
they should provide their own aer service drivers with reset_link
function. If error_detected returns PCI_ERS_RESULT_CAN_RECOVER and
reset_link returns PCI_ERS_RESULT_RECOVERED, the error handling goes
@@ -249,11 +250,11 @@ cleanup uncorrectable status register. Pls. refer to section 3.3.
4. Software error injection
Debugging PCIE AER error recovery code is quite difficult because it
Debugging PCIe AER error recovery code is quite difficult because it
is hard to trigger real hardware errors. Software based error
injection can be used to fake various kinds of PCIE errors.
injection can be used to fake various kinds of PCIe errors.
First you should enable PCIE AER software error injection in kernel
First you should enable PCIe AER software error injection in kernel
configuration, that is, following item should be in your .config.
CONFIG_PCIEAER_INJECT=y or CONFIG_PCIEAER_INJECT=m