RISC-V interrupt vectoring

[Denis Obrezkov]

2017-07-03 7:43 GMT+02:00 Hesham Almatary <heshamelmatary at gmail.com>:

> On Mon, Jul 3, 2017 at 3:36 PM, Denis Obrezkov <denisobrezkov at gmail.com>
> wrote:
> > 2017-07-03 4:59 GMT+02:00 Hesham Almatary <heshamelmatary at gmail.com>:
> >>
> >> You can have a look at riscv-pk [1] as a RISC-V reference how to
> >> handle interrupts. RTEMS-wise, you can look at or1k and ARM code and
> >> how the platform-dependent interrupt handling code is linked to
> >> platform-independent one.
> >>
> >> mcause value can be used as an index to a software vector table that you
> >> set up.
> >>
> >> Why do you need software interrupts? GSoC-wise, I thought the plan was
> >> to develop UART/Console driver (which doesn't need interrupts), and
> >> use simulated ticker, as a first step. Then it will be easier to
> >> debug/proceed from there with interrupt handling code.
> >
> > I thought, I have to implement an interrupt console driver. Okay, then I
> am
> > going to
> > investigate a simulated ticker.
> Yeah that can be done in later stages, for optimisation purposes. But
> I think it's easier to implement it in polling mode first, just to get
> things working, then you can easily move to interrupt-based
> implementation. For example, if you've a polling console driver, you
> can debug using printk, when developing the clock driver. Once you get
> the clock driver working, you will have a more mature code for
> interrupt handling, which enables you to very easily implement
> interrupt-based UART driver.
> > --
> > Regards, Denis Obrezkov
>
>
>
> --
> Hesham
>

It seems that vectored interrupts aren't available in FE310 SoC.
Thus, I will work with mcause register.
As for now, I want to:
* add local interrupt handlers
* add init code for counters initializtion (since we want to set up a
baudrate)
* implement a dummy clock driver
* implement a polling uart
* figure out how interrupts are handled in RTEMS
* implement global interrupt handlers
* implement a clock driver
* implement an interrupt-mode uart driver.



-- 
Regards, Denis Obrezkov
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