Messages in this thread | | | Date | Thu, 16 Feb 2023 12:32:10 +0100 | Subject | Re: [PATCH 1/2] hwrng: add driver for MediaTek TRNG SMC | From | Matthias Brugger <> |
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On 16/02/2023 11:03, AngeloGioacchino Del Regno wrote: > Il 15/02/23 14:27, Daniel Golle ha scritto: >> Add driver providing kernel-side support for the Random Number >> Generator hardware found on Mediatek SoCs which have a driver in ARM >> TrustedFirmware-A allowing Linux to read random numbers using a >> non-standard vendor-defined Secure Monitor Call. >> >> Signed-off-by: Daniel Golle <daniel@makrotopia.org> > > Hello Daniel, > > incidentally, I've also done some research on this one some months ago, when > I was deep in adding support for the Helio X10 SoC (MT6795) on Xperia M5. > > The rng-v2 is simply the same rng but hypervised by the TF-A... and the only > difference is, well, as you're also pointing out, that we're using secure > monitor calls instead of direct MMIO handling. > > There's also not much more than what you've implemented here and the only kind > of addition that we will ever see on this one will be about changing the SIP > command (as some older SoCs use a different one)... so... > > ...I don't think that adding an entirely new driver is worth the noise, hence > I propose to simply add handling for the Secure RNG to mtk-rng.c instead: it's > shorter and we would only need to address one if branch on that probe function > to set a different callback. > > The clock should then be optional for *some* of those "v2 handling" devices, > as if I recall correctly, some do need the clock to be handled from Linux > anyway... otherwise this v2 driver will be "soon" looking bloody similar to > the "v1", adding a bit of code duplication around. > > What do you think? >
That was exactly what I was thinking as well when I had a look at the driver. I propose to add it to mtk-rng.c. I don't see any value having a second driver for this.
Regards, Matthias
> Regards, > Angelo > >> --- >> MAINTAINERS | 1 + >> drivers/char/hw_random/Kconfig | 16 +++++++ >> drivers/char/hw_random/Makefile | 1 + >> drivers/char/hw_random/mtk-rng-v2.c | 74 +++++++++++++++++++++++++++++ >> 4 files changed, 92 insertions(+) >> create mode 100644 drivers/char/hw_random/mtk-rng-v2.c >> >
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