7919dfd84b
[ Upstream commit 680efb33546be8960ccbb2f4e0e43034d9c93b30 ] This RNG device is present on Marvell OcteonTx2 silicons as well and also provides entropy health status. HW continuously checks health condition of entropy and reports faults. Fault is in terms of co-processor cycles since last fault detected. This doesn't get cleared and only updated when new fault is detected. Also there are chances of detecting false positives. So to detect a entropy failure SW has to check if failures are persistent ie cycles elapsed is frequently updated by HW. This patch adds support to detect health failures using below algo. 1. Consider any fault detected before 10ms as a false positive and ignore. 10ms is chosen randomly, no significance. 2. Upon first failure detection make a note of cycles elapsed and when this error happened in realtime (cntvct). 3. Upon subsequent failure, check if this is new or a old one by comparing current cycles with the ones since last failure. cycles or time since last failure is calculated using cycles and time info captured at (2). HEALTH_CHECK status register is not available to VF, hence had to map PF registers. Also since cycles are in terms of co-processor cycles, had to retrieve co-processor clock rate from RST device. Signed-off-by: Sunil Goutham <sgoutham@marvell.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.