selftests/powerpc: Add basic EEH selftest
Use the new eeh_dev_check and eeh_dev_break interfaces to test EEH recovery. Historically this has been done manually using platform specific EEH error injection facilities (e.g. via RTAS). However, documentation on how to use these facilities is haphazard at best and non-existent at worst so it's hard to develop a cross-platform test. The new debugfs interfaces allow the kernel to handle the platform specific details so we can write a more generic set of sets. This patch adds the most basic of recovery tests where: a) Errors are injected and recovered from sequentially, b) Errors are not injected into PCI-PCI bridges, such as PCIe switches. c) Errors are only injected into device function zero. d) No errors are injected into Virtual Functions. a), b) and c) are largely due to limitations of Linux's EEH support. EEH recovery is serialised in the EEH recovery thread which forces a). Similarly, multi-function PCI devices are almost always grouped into the same PE so injecting an error on one function exercises the same code paths. c) is because we currently more or less ignore PCI bridges during recovery and assume that the recovered topology will be the same as the original. d) is due to the limits of the eeh_dev_break interface. With the current implementation we can't inject an error into a specific VF without potentially causing additional errors on other VFs. Due to the serialised recovery process we might end up timing out waiting for another function to recover before the function of interest is recovered. The platform specific error injection facilities are finer-grained and allow this capability, but doing that requires working out how to use those facilities first. Basicly, it's better than nothing and it's a base to build on. Signed-off-by:Oliver O'Halloran <oohall@gmail.com> Signed-off-by:
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