Re: [patches] Re: [PATCH 2/7] RISC-V: arch/riscv Makefile and Kconfigs

[Benjamin Herrenschmidt]

On Mon, 2017-05-22 at 22:16 -0700, Olof Johansson wrote:
> The same is true for some other drivers. Actually, I wonder if it
> might be just as easy to implement a sbi backend for hvc -- see
> hvc_udbg.c for an example where, on power, you have a simple get/put
> char hypervisor call in a very similar manner.

Rather look at hvc_opal. This is the console driver we use on native
POWER servers with the OPAL firmware, and it calls into a firmware
in a very similar way.

The driver lives in drivers/tty/hvc. It does call some "helpers" in
the arch code that wrap the actual FW calls.

> Either way (keeping discrete sbi driver or implementing hvc backend),
> moving to drivers/tty is the right thing here -- we've worked hard on
> ARM to get rid of random drivers under arch/ and it'd be nice to not
> see new ones intoduced here.

Yup. The reason mostly is that if the tty maintainer needs to do a
subsystem-wide change, he can address all drivers in drivers/tty and
doesn't have to look for others elsewhere in the tree. This is the same
for all subsystems.

Cheers,
Ben.