Re: Usage of pci bus

[Gautam Bhat]

On Fri, Jun 19, 2020 at 2:02 AM Peter Maydell <peter.maydell@linaro.org> wrote:
>
> On Thu, 18 Jun 2020 at 20:36, Gautam Bhat <mindentropy@gmail.com> wrote:
> > I am confused with the usage of PCI bus for connecting different
> > peripherals. If I want to emulate an ARM board which doesn't have a
> > PCI controller how can I emulate it to be as close to the real board
> > as possible? Is there an ARM interconnect or something where I can
> > connect the peripheral controllers and the peripherals to these
> > controllers?
>
> I'm not sure what you're asking here. If the board you want
> to emulate doesn't have a PCI controller, then just don't
> implement a model of a PCI controller. You won't be able
> to use any PCI devices, but that's fine, because the real
> hardware you're modelling doesn't have PCI devices.
> Most of the devices you emulate are going to be the simple
> straightforward type which have some MMIO-mapped registers
> and an interrupt line. In QEMU we call those "sysbus" devices;
> there are lots of examples in the tree.
>
> thanks
> -- PMM

Basically I want to model ARM structure as below:

ARM Core <-- APB---> I2C Controller <------> I2C device.

Is the APB emulated?

>From the code I see sysbus calls are done inside the emulated I2C
controller which would call the emulated I2C send, recv and event. Is
my understanding correct? Is there a sysbus instead of APB?

-Gautam.