Re: [PATCH 2/3] msm: Peripheral Image Loader (PIL) driver

[Saravana Kannan]

On 03/16/2011 11:40 AM, David Brown wrote:
> On Wed, Mar 16 2011, Daniel Walker wrote:
>
> > On Wed, 2011-03-09 at 20:44 -0800, Stephen Boyd wrote:
> > > On 8660, the modem, dsp, and sensors peripherals require their
> > > firmware to be loaded into memory before they can be properly
> > > taken out of reset.
> > >
> > > Drivers are expected to call pil_get() when they wish to load a
> > > peripheral. This will initiate multiple firmware_request()s for
> > > the metadata and image blobs for a peripheral. Once the image has
> > > been loaded into memory, it is validated and brought out of reset
> > > via the peripheral reset driver.
> >
> > Why can't this be part of the generic firmware request API ?
>
> Can you clarify what you mean by this?  The firmware request API is used
> to get the firmware itself, which this code uses.  This code is what
> manages making those calls for the various MSM peripherals that require
> firmware.
>
> > > diff --git a/arch/arm/mach-msm/Kconfig b/arch/arm/mach-msm/Kconfig
> > > index 997c5bd..25b73b0 100644
> > > --- a/arch/arm/mach-msm/Kconfig
> > > +++ b/arch/arm/mach-msm/Kconfig
> > > @@ -210,4 +210,17 @@ config IOMMU_API
> > >
> > >   config MSM_SCM
> > >          bool
> > > +
> > > +config MSM_PIL
> > > +       bool "Peripheral image loading (PIL)"
> > > +       select FW_LOADER
> > > +       select MSM_SCM
> > > +       depends on ARCH_MSM8X60
> > > +       help
> > > +         Some peripherals need to be loaded into memory before they
> > > can be
> > > +         brought out of reset.
> > > +
> > > +         Say yes to support these devices.
> > > +
> > > +
> >
> > You shouldn't be adding anything like this to the Kconfig. To me if you
> > add stuff like this it's a big red flag.
>
> Can you clarify what you mean "stuff like this".
>
> It seems to me that this option should be selected by the drivers that
> need it, since it doesn't make sense to have this if there are no
> drivers that need it, and it is required when those drivers are
> included.
>
> I do think there are valid hardware configurations that don't have any
> peripherals needing firmware, and would think that those should be able
> to avoid requiring the code to manage that.  Saravana/Stephen can
> clarify that, though.

Correct. There are plenty of Qualcomm SoCs that don't need this driver. 
There are also valid 8660 configurations that would not need this.

Thanks,
Saravana

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