Evgeniy Polyakov wrote:
On Sat, Nov 17, 2007 at 08:30:09PM +0100, Patrick McHardy (kaber@xxxxxxxxx) wrote:
The second patch adds hw_random support. The ugly part is finding out
when to allow reads from the RNG. It currently translates the public
key engine clock cycles to CPU cycles based on a 4GHz CPU and uses
get_cycles(). The problems with this are obvious, it only works on CPUs
that actually have some kind of cycle counter, has problems with
unsynchronized TSCs and the 4GHz assumption is not very nice either,
but I was reluctant to use ktime for this since it seems rather
expensive to call ktime_get once per 4 bytes of random. Suggestion
for improvement of this are also welcome :)
It will not work on arm, but I'm not sure this is relevant...
Another option is to directly access xtime without all wrappers in the
ktime_get().
I'll look into that, thanks.
Running rngtest on the random number generator indicates that it works
properly, with an average failure ratio of about 1:1000 at ~2.5mbit.
drivers/crypto/hifn_795x.c | 158 +++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 156 insertions(+), 2 deletions(-)
Patrick McHardy (2):
[HIFN]: Improve PLL initialization
[HIFN]: Add support for using the random number generator
Ack both patches.
Just in case, they shouldn't be applied yet, I forgot one minor bit
when splitting them (discarding the first value read from the RNG).
The PLL initialization also doesn't seem to follow the specified way
from the documentation, I want to have another look at this.
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