On Thu, Aug 05, 2021 at 10:15:06AM -0600, Mathieu Poirier wrote:
> On Wed, Aug 04, 2021 at 11:03:57PM +0200, Martin Blumenstingl wrote:
> > Hi Mathieu,
> >
> > thanks for taking the time to look into this!
> >
> > (I will address any of your comments that I am not mentioning in this
> > email anymore. Thanks a lot for the suggestions!)
> >
> > On Wed, Jul 28, 2021 at 7:58 PM Mathieu Poirier
> > <mathieu.poirier@xxxxxxxxxx> wrote:
> > [...]
> > > > + writel(FIELD_PREP(AO_REMAP_REG0_REMAP_AHB_SRAM_BITS_17_14_FOR_ARM_CPU,
> > > > + priv->sram_pa >> 14),
> > > Indentation problem
> > The idea here is to align priv->sram_pa with AO_REMAP_REG0... which
> > are both arguments to FIELD_PREP
>
> Right, this is what I would have expected. When I applied the patch on my side
> "priv->sram_pa ..." was aligned wiht the 'M' of "AO_REMAP_ ...".
>
> > Maybe using something like this will make that easier to read:
> > tmp = FIELD_PREP(AO_REMAP_REG0_REMAP_AHB_SRAM_BITS_17_14_FOR_ARM_CPU,
> > priv->sram_pa >> 14);
> > writel(tmp, priv->remap_base + AO_REMAP_REG0);
>
> I think the main problem is that
> AO_REMAP_REG0_REMAP_AHB_SRAM_BITS_17_14_FOR_ARM_CPU is simply too long. I
> suggest making is shorter and add a comment to describe exactly what it does.
>
> >
> > What do you think: leave it as is or use a separate variable?
> >
> > [...]
> > > > + usleep_range(10, 100);
> > >
> > > I've seen this kind of mysterious timeouts in other patchset based vendor trees.
> > > You likely don't know why it is needed so I won't ask.
> > unfortunately this is also the case here
> >
> > [...]
> > > > + priv->arc_reset = devm_reset_control_get_exclusive(dev, NULL);
> > > > + if (IS_ERR(priv->arc_reset)) {
> > >
> > > Function __reset_control_get() in __devm_reset_control_get() can return NULL so
> > > this should be IS_ERR_OR_NULL().
> > The logic in there is: return optional ? NULL : ERR_PTR(-...);
>
> Ok, so you meant to do that. And I just checked reset_control_reset() and it does
> account for a NULL parameter. I'm good with this one but add a comment to
> make sure future readers don't think you've omitted to properly deal with the
> NULL return value.
>
> > I am requesting a mandatory reset line here, so reset core will never
> > return NULL
> > See also [0]
>
> Indeed, I've read that too. Nonetheless __reset_control_get() can return NULL
> by way of __reset_control_get_from_lookup().
>
You are correct, in your case checking for IS_ERR() is sufficient.
> >
> > For this reason I am not planning to change this
> >
> > [...]
> > > This driver is squeaky clean. With the above:
> > >
> > > Reviewed-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> > awesome, thank you!
> >
> >
> > Best regards,
> > Martin
> >
> >
> > [0] https://elixir.bootlin.com/linux/v5.14-rc4/source/include/linux/reset.h#L227
