RE: [PATCH v6 04/11] firmware: xilinx: Add query data API

[Jolly Shah]

HI Sudeep,

> -----Original Message-----
> From: Sudeep Holla [mailto:sudeep.ho...@arm.com]
> Sent: Thursday, May 10, 2018 7:12 AM
> To: Jolly Shah <jol...@xilinx.com>; ard.biesheu...@linaro.org;
> mi...@kernel.org; gre...@linuxfoundation.org; m...@codeblueprint.co.uk;
> hkallwe...@gmail.com; keesc...@chromium.org;
> dmitry.torok...@gmail.com; mturque...@baylibre.com;
> sb...@codeaurora.org; michal.si...@xilinx.com; robh...@kernel.org;
> mark.rutl...@arm.com; linux-...@vger.kernel.org
> Cc: Sudeep Holla <sudeep.ho...@arm.com>; Rajan Vaja <raj...@xilinx.com>;
> linux-arm-ker...@lists.infradead.org; linux-kernel@vger.kernel.org;
> devicet...@vger.kernel.org; Jolly Shah <jol...@xilinx.com>
> Subject: Re: [PATCH v6 04/11] firmware: xilinx: Add query data API
> 
> 
> 
> On 10/04/18 20:38, Jolly Shah wrote:
> > From: Rajan Vaja <raj...@xilinx.com>
> >
> > Add ZynqMP firmware query data API to query platform specific
> > information(clocks, pins) from firmware.
> >
> > Signed-off-by: Rajan Vaja <raj...@xilinx.com>
> > Signed-off-by: Jolly Shah <jol...@xilinx.com>
> > ---
> >  drivers/firmware/xilinx/zynqmp.c     | 14 ++++++++++++++
> >  include/linux/firmware/xlnx-zynqmp.h | 20 ++++++++++++++++++++
> >  2 files changed, 34 insertions(+)
> >
> > diff --git a/drivers/firmware/xilinx/zynqmp.c
> > b/drivers/firmware/xilinx/zynqmp.c
> > index 44b43fa..ef09c44 100644
> > --- a/drivers/firmware/xilinx/zynqmp.c
> > +++ b/drivers/firmware/xilinx/zynqmp.c
> > @@ -258,9 +258,23 @@ static int zynqmp_pm_ioctl(u32 node_id, u32
> ioctl_id, u32 arg1, u32 arg2,
> >                                arg1, arg2, out);
> >  }
> >
> > +/**
> > + * zynqmp_pm_query_data() - Get query data from firmware
> > + * @qdata: Variable to the zynqmp_pm_query_data structure
> > + * @out:   Returned output value
> > + *
> > + * Return: Returns status, either success or error+reason  */ static
> > +int zynqmp_pm_query_data(struct zynqmp_pm_query_data qdata, u32 *out)
> > +{
> > +   return zynqmp_pm_invoke_fn(PM_QUERY_DATA, qdata.qid,
> qdata.arg1,
> > +                              qdata.arg2, qdata.arg3, out);
> > +}
> > +
> >  static const struct zynqmp_eemi_ops eemi_ops = {
> >     .get_api_version = zynqmp_pm_get_api_version,
> >     .ioctl = zynqmp_pm_ioctl,
> > +   .query_data = zynqmp_pm_query_data,
> 
> Can you give more insight into this ? How will be this used ?
> How this aligns with data we get from DT ? I am just trying to understand how 
> is
> this information split between this API and DT for example.
> 
> --
> Regards,
> Sudeep

This API is used to get clock information from firmware and register clocks 
accordingly in driver. In our case, firmware maintains database of all clocks 
available on chip. DT will provide information for off chip reference clocks 
only.
This is to avoid duplication of clocks data in DT and firmware both as firmware 
anyways need clock data to manage them.

Thanks,
Jolly Shah