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Date:   Thu, 21 Jul 2022 11:54:11 +0300
From:   Ivan Bornyakov <i.bornyakov@metrotek.ru>
To:     Xu Yilun <yilun.xu@intel.com>
Cc:     mdf@kernel.org, hao.wu@intel.com, trix@redhat.com,
        robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
        linux-fpga@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, system@metrotek.ru
Subject: Re: [PATCH v5 0/2] Lattice ECP5 FPGA manager
Message-ID: <20220721085411.ennvx74k45sxsimm@h-e2.ddg>
References: <20220719112335.9528-1-i.bornyakov@metrotek.ru>
 <20220721074431.GA1712998@yilunxu-OptiPlex-7050>
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On Thu, Jul 21, 2022 at 03:44:31PM +0800, Xu Yilun wrote:
> On Tue, Jul 19, 2022 at 02:23:33PM +0300, Ivan Bornyakov wrote:
> > Add support to the FPGA manager for programming Lattice ECP5 FPGA over
> > slave SPI interface with .bit formatted uncompressed bitstream image.
> 
> I didn't have time to looking into the patches yet, but I have some quick
> question.
> 
> Where is the bitstream data writing to? To the FPGA active region or the
> backup nvmem like flash?

Bitstream is written to FPGA's volatile SRAM configuration memory.

> 
> After reconfiguration, how to re-enumerate the hardware devices in the
> newly programmed FPGA region?
> 

I personally describe FPGA-based devices statically in DT overlay within
fpga-region. Of course this approach is error prone to mismatch between
firmware and devices described in DT overlay...

> Thanks,
> Yilun
> 
> > 
> > ChangeLog:
> >   v1 -> v2:
> >     * remove "spi" from compatible string
> >     * reword description in dt-bindings doc
> >     * add reference to spi-peripheral-props.yaml in dt-binding doc
> >     * fix DTS example in dt-bindings doc: 4-spaces indentations, no
> >       undersores in node names.
> >   v2 -> v3:
> >     * fix typo "##size-cells" -> "#size-cells" in dt-bindings example
> >   v3 -> v4:
> >     * dt-bindings: reword description
> >     * dt-bindings: revert props order
> >   v4 -> v5:
> >     * dt-bindings: remove trailing dot from title
> >     * dt-bindings: reword description to avoid driver reference
> >     * dt-bindings: add "Reviewed-by: Krzysztof Kozlowski" tag
> > 
> > Ivan Bornyakov (2):
> >   fpga: ecp5-spi: add Lattice ECP5 FPGA manager
> >   dt-bindings: fpga: add binding doc for ecp5-spi fpga mgr
> > 
> >  .../bindings/fpga/lattice,ecp5-fpga-mgr.yaml  |  74 +++++
> >  drivers/fpga/Kconfig                          |   7 +
> >  drivers/fpga/Makefile                         |   1 +
> >  drivers/fpga/ecp5-spi.c                       | 275 ++++++++++++++++++
> >  4 files changed, 357 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/fpga/lattice,ecp5-fpga-mgr.yaml
> >  create mode 100644 drivers/fpga/ecp5-spi.c
> > 
> > -- 
> > 2.37.1
> >