RE: [PATCH v5 01/12] bbdev: add FFT window width member in driver info

["Chautru, Nicolas" <nicolas.chautru@intel.com>]

Hi Maxime, 

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Friday, October 6, 2023 12:54 AM
> To: Chautru, Nicolas <nicolas.chautru@intel.com>; dev@dpdk.org
> Cc: hemant.agrawal@nxp.com; david.marchand@redhat.com; Vargas, Hernan
> <hernan.vargas@intel.com>
> Subject: Re: [PATCH v5 01/12] bbdev: add FFT window width member in driver
> info
> 
> 
> 
> On 10/5/23 21:48, Nicolas Chautru wrote:
> > This exposes the width of each windowing shape being configured on the
> > device. This allows to distinguish different version of the flexible
> > pointwise windowing applied to the FFT and expose this platform
> > configuration to the application.
> > This also add the total number of windows supported in the capability.
> >
> > The SRS processing chain
> > (https://doc.dpdk.org/guides/prog_guide/bbdev.html#bbdev-fft-operation
> > ) includes a pointwise multiplication by time window whose shape width
> > needs to be exposed, notably for accurate SNR estimate.
> > Using that mechanism user application can retrieve information related
> > to what has been dynamically programmed on any bbdev device supporting
> > FFT windowing operation.
> >
> > Signed-off-by: Nicolas Chautru <nicolas.chautru@intel.com>
> > ---
> >   lib/bbdev/rte_bbdev.h    | 2 ++
> >   lib/bbdev/rte_bbdev_op.h | 2 ++
> >   2 files changed, 4 insertions(+)
> >
> > diff --git a/lib/bbdev/rte_bbdev.h b/lib/bbdev/rte_bbdev.h index
> > 2985c9f42b..d12e2e7fbc 100644
> > --- a/lib/bbdev/rte_bbdev.h
> > +++ b/lib/bbdev/rte_bbdev.h
> > @@ -349,6 +349,8 @@ struct rte_bbdev_driver_info {
> >   	const struct rte_bbdev_op_cap *capabilities;
> >   	/** Device cpu_flag requirements */
> >   	const enum rte_cpu_flag_t *cpu_flag_reqs;
> > +	/** FFT windowing width for 2048 FFT - size defined in capability. */
> > +	uint16_t *fft_window_width;
> >   };
> >
> >   /** Macro used at end of bbdev PMD list */ diff --git
> > a/lib/bbdev/rte_bbdev_op.h b/lib/bbdev/rte_bbdev_op.h index
> > 693baa8386..369ac331bf 100644
> > --- a/lib/bbdev/rte_bbdev_op.h
> > +++ b/lib/bbdev/rte_bbdev_op.h
> > @@ -905,6 +905,8 @@ struct rte_bbdev_op_cap_fft {
> >   	uint16_t num_buffers_src;
> >   	/** Num output code block buffers. */
> >   	uint16_t num_buffers_dst;
> > +	/** Number of FFT windows supported. */
> > +	uint16_t fft_windows_num;
> >   };
> >
> >   /** List of the capabilities for the MLD */
> 
> I am Ok to move forwards with this, even if I would have liked feedback from
> Hemant.
> 
> However, I think you need to add some documentation around it, as what is in
> the commit message is important and won't be visible to the end- user.

Can we extend the documentation in incremental serie? There other things that could arguably be exposed more clearly, not just this one but more generally on device enumeration which is currently limited (pretty much everything from info_get).  

> 
> Thanks,
> Maxime