Re: [RFC] Short Circuit simplest Rust driver that touches real hardware?

[Greg KH <greg@kroah.com>]

On Mon, Apr 26, 2021 at 10:58:10PM +0200, Geert Stappers wrote:
> On Mon, Apr 26, 2021 at 03:47:59PM -0400, Sven Van Asbroeck wrote:
> >         ...
> > 2. implement the simplest `IoMemBlock` in Rust. Since we have a live
> > `struct device *`, the `IoMemBlock` constructor can simply call
> > `devm_platform_get_and_ioremap_resource(our struct device *)` in C,
> > which will automatically use the right method to retrieve the `void
> > __iomem *`: devicetree, platform data, etc, we don't have to care.
> > 3. use the `IoMemBlock` above to implement a trivial iomem-only driver
> > as a module. A few possible candidates:
> > * h/w random number generator in Raspberry Pi Zero: `brcm,bcm2835-rng`
> > * SoC thermal sensor in Raspberry Pi Zero: `brcm,bcm2835-thermal`
> > 4. we don't have `hwrng` or `thermal_hwmon` devices in Rust yet, but
> > we could perhaps expose this as a `misc_device`, which is something we
> > already have. A single temp or randnum readout might do the trick.
> > 
> > The Raspberry Pi Zero can be purchased for $10. There is [QEMU
> > support](https://qemu.readthedocs.io/en/latest/system/arm/raspi.html)
> > for the peripherals above.
> > 
> > Feedback and ideas welcome !
> 
> Hope that hardware manufactures see this opportunity.  Because I fear that
> this cool project might get botched due lack of knowledge on hardware.
> 
> 
> Implementing kernel module for 8250 UART in Rust is something that
> wouldn't get botched due lack of hardware knowledge.

Uarts are anything but simple, sorry, look at how "big" the kernel
driver is in C for the 8250 support.

And yes, I recommend doing a "simple" driver that touches the hardware,
there's no reason not to duplicate one of the existing C drivers, in
fact, it makes more sense so that people can help understand the
comparison between the ways the two languages will work.

thanks,

greg k-h