[maemo-developers] [maemo-developers] Huge bundle O' year-end questions

[From: Juha Yrjölä]

Hi Jason,

On Sat, 2005-12-31 at 02:53 -0800, ext Jason Mills wrote:

> * How does one get access to the hardware Random Number Generator? (Is that
> what /dev/urandom is pinned to?)

No way with the current kernel.  At the moment we just populate the
kernel entropy pools with some amount of randomness from the RNG at
bootup time.  Reading from /dev/random should be pretty safe, though.

> * How does one get access to the hardware crypto accelerators? (SHA1/MD5,
> DES/3DES)

By writing a kernel driver for those.  There isn't anything yet.

> * How does one get access to the hardware/software Java acceleration?

That's a feature in the ARM core.  Getting it up and running can be
rather tricky, since there doesn't seem to be a lot of public
documentation.  Check the linux-arm-kernel mailing list archives for
more info.

> * Is it possible to get access to the ARM9's "secure" mode to lock down a
> segment of memory and processor space for crypto stuff? The processor itself
> supports it, but I don't know if Maemo/Hildon do/will.

There is no real secure mode in ARM9.  There is the OMAP security stuff,
but that cannot be used with the OMAPs that are in the 770.

> * Has T.I. delivered all required docs/sample-libraries/what-have-you to
> Nokia and the Maemo.org teams so that the N770 and other Maemo/Hildon devices
> may take full advantage of this slick bit of silicon?

Yes.

> * Would it, in that context, be advisable to separate the OMAP1710 from the
> earlier bretheren (OMAP16xx f'rexample) when dealing with the Linux - ARM9 -
> OMAP1xxx kernel branch, since they feature radically different cache sizes
> and value-add functionality?

We are already separating them in all the places that matter.

> * Why does the hardware currently report that frame-buffer acceleration is
> -disabled-? (At least, that's what I'm gathering from the value in that
> particular SysFS node)

Since there is no real framebuffer acceleration to speak of.  We can do
some operations in HW by using the OMAP System DMA, but it was found not
to be any faster than just using the MPU.

> Kernel/Compiler:
> * W/r2 hardware crypto, no crypto modules were enabled for the Linux kernel
> (2.6.12.3-omap1) currently in use. Was/is this pending addition of said
> hardware crypto support?

There are no plans to add HW crypto for the 770 yet, and no real
benefits considering the 770 application base.

If someone comes up with a really cool app that would benefit from HW
crypto acceleration, we will of course reconsider. =)

Cheers,
Juha