[PATCH v3 5/6] sandbox: Enable memio operations in board_init

[Simon Glass]

Hi Pratyush,

On Mon, 3 Aug 2020 at 05:34, Pratyush Yadav <p.yadav at ti.com> wrote:
>
> Hi Simon,
>
> On 16/06/20 09:12PM, Simon Glass wrote:
> > Hi Pratyush,
> >
> > On Thu, 11 Jun 2020 at 13:45, Pratyush Yadav <p.yadav at ti.com> wrote:
> > >
> > > initr_dm_devices() is called somewhere after board_init(). It can be
> > > used by drivers to initialize devices to some default bootup state.
> > > Those devices might use mmio read/write operations to perform the
> > > initialization.
> > >
> > > One such example is the mux devices. The mux framework initializes the
> > > muxes to their default state after idle state in
> > > mux_uclass_post_probe(). One type of mux controller is the MMIO mux
> > > controller. Initializing a MMIO mux to idle state can require a mmio
> > > read and write operation.
> > >
> > > With memio disabled, the reads return 0 and the writes go off into the
> > > void. This makes it impossible to initialize muxes to their idle state
> > > on boot, and consequentially makes it impossible to test that in
> > > sandbox.
> > >
> > > These same initializations work fine on actual hardware (tested on TI
> > > J721E EVM). So, enable memio operations on boot so devices like mux can
> > > perform whatever initialization they need. state_reset_for_test() will
> > > disable it before running tests so tests still need to enable memio
> > > manually.
> >
> > We have a similar issue with PCI and we only enable it when needed.
> > Can we do something similar here?
>
> I went and looked, but I can't figure out how we do it for PCI. Any
> pointers?

Yes it is enable_pci_map in arch/sandbox/cpu/cpu.c

Regards,
Simon