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

[Pratyush Yadav]

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?
 
> >
> > Signed-off-by: Pratyush Yadav <p.yadav at ti.com>
> > ---
> >  board/sandbox/sandbox.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/board/sandbox/sandbox.c b/board/sandbox/sandbox.c
> > index 1372003018..d7eb207822 100644
> > --- a/board/sandbox/sandbox.c
> > +++ b/board/sandbox/sandbox.c
> > @@ -55,6 +55,8 @@ int board_init(void)
> >         if (IS_ENABLED(CONFIG_LED))
> >                 led_default_state();
> >
> > +       sandbox_set_enable_memio(true);
> > +
> >         return 0;
> >  }

-- 
Regards,
Pratyush Yadav
Texas Instruments India