RE: [PATCH 3/3] fpga manager: Adding FPGA Manager support for Xilinx zynqmp

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Hi Moritz,

Thanks for the quick response..
Please find my response inline.

> -----Original Message-----
> From: Moritz Fischer [mailto:mdf@xxxxxxxxxx]
> Sent: Monday, October 22, 2018 3:53 PM
> To: Nava kishore Manne <navam@xxxxxxxxxx>
> Cc: Moritz Fischer <moritz.fischer@xxxxxxxxx>; Moritz Fischer
> <moritz.fischer.private@xxxxxxxxx>; Alan Tull <atull@xxxxxxxxxx>; Rob Herring
> <robh+dt@xxxxxxxxxx>; Mark Rutland <mark.rutland@xxxxxxx>; Michal Simek
> <michals@xxxxxxxxxx>; Rajan Vaja <RAJANV@xxxxxxxxxx>; Jolly Shah
> <JOLLYS@xxxxxxxxxx>; linux-fpga@xxxxxxxxxxxxxxx; Devicetree List
> <devicetree@xxxxxxxxxxxxxxx>; linux-arm-kernel <linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx>; Linux Kernel Mailing List <linux-
> kernel@xxxxxxxxxxxxxxx>; chinnikishore369@xxxxxxxxx
> Subject: Re: [PATCH 3/3] fpga manager: Adding FPGA Manager support for
> Xilinx zynqmp
> 
> On Mon, Oct 22, 2018 at 10:03:55AM +0000, Nava kishore Manne wrote:
> > Hi Mortiz,
> >
> > Thanks for the quick response....
> > Please find my response inline.
> >
> > > -----Original Message-----
> > > From: Moritz Fischer [mailto:moritz.fischer@xxxxxxxxx]
> > > Sent: Saturday, October 20, 2018 7:02 AM
> > > To: Moritz Fischer <moritz.fischer.private@xxxxxxxxx>
> > > Cc: Nava kishore Manne <navam@xxxxxxxxxx>; Alan Tull
> > > <atull@xxxxxxxxxx>; Rob Herring <robh+dt@xxxxxxxxxx>; Mark Rutland
> > > <mark.rutland@xxxxxxx>; Michal Simek <michals@xxxxxxxxxx>; Rajan
> > > Vaja <RAJANV@xxxxxxxxxx>; Jolly Shah <JOLLYS@xxxxxxxxxx>;
> > > linux-fpga@xxxxxxxxxxxxxxx; Devicetree List
> > > <devicetree@xxxxxxxxxxxxxxx>; linux-arm-kernel <linux-arm-
> > > kernel@xxxxxxxxxxxxxxxxxxx>; Linux Kernel Mailing List <linux-
> > > kernel@xxxxxxxxxxxxxxx>; chinnikishore369@xxxxxxxxx
> > > Subject: Re: [PATCH 3/3] fpga manager: Adding FPGA Manager support
> > > for Xilinx zynqmp
> > >
> > > On Fri, Oct 19, 2018 at 2:33 PM Moritz Fischer
> > > <moritz.fischer.private@xxxxxxxxx> wrote:
> > > >
> > > > Hi Nava,
> > > >
> > > > Looks good to me, a couple of nits inline below.
> > > >
> > > > On Fri, Oct 19, 2018 at 1:50 AM Nava kishore Manne
> > > > <nava.manne@xxxxxxxxxx> wrote:
> > > > >
> > > > > This patch adds FPGA Manager support for the Xilinx ZynqMp chip.
> > > >
> > > > Isn't it ZynqMP ?
> > > > >
> > > > > Signed-off-by: Nava kishore Manne <nava.manne@xxxxxxxxxx>
> > > > > ---
> > > > > Changes for v1:
> > > > >                 -None.
> > > > >
> > > > > Changes for RFC-V2:
> > > > >                 -Updated the Fpga Mgr registrations call's
> > > > >                  to 4.18
> > > > >
> > > > >  drivers/fpga/Kconfig       |   9 +++
> > > > >  drivers/fpga/Makefile      |   1 +
> > > > >  drivers/fpga/zynqmp-fpga.c | 159
> > > > > +++++++++++++++++++++++++++++++++++++
> > > > >  3 files changed, 169 insertions(+)  create mode 100644
> > > > > drivers/fpga/zynqmp-fpga.c
> > > > >
> > > > > diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig index
> > > > > 1ebcef4bab5b..26ebbcf3d3a3 100644
> > > > > --- a/drivers/fpga/Kconfig
> > > > > +++ b/drivers/fpga/Kconfig
> > > > > @@ -56,6 +56,15 @@ config FPGA_MGR_ZYNQ_FPGA
> > > > >         help
> > > > >           FPGA manager driver support for Xilinx Zynq FPGAs.
> > > > >
> > > > > +config FPGA_MGR_ZYNQMP_FPGA
> > > > > +       tristate "Xilinx Zynqmp FPGA"
> > > > > +       depends on ARCH_ZYNQMP || COMPILE_TEST
> > > > > +       help
> > > > > +         FPGA manager driver support for Xilinx ZynqMP FPGAs.
> > > > > +         This driver uses processor configuration port(PCAP)
> > > > This driver uses *the* processor configuration port.
> > > >
> > > > > +         to configure the programmable logic(PL) through PS
> > > > > +         on ZynqMP SoC.
> > > > > +
> > > > >  config FPGA_MGR_XILINX_SPI
> > > > >         tristate "Xilinx Configuration over Slave Serial (SPI)"
> > > > >         depends on SPI
> > > > > diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile index
> > > > > 7a2d73ba7122..3488ebbaee46 100644
> > > > > --- a/drivers/fpga/Makefile
> > > > > +++ b/drivers/fpga/Makefile
> > > > > @@ -16,6 +16,7 @@ obj-$(CONFIG_FPGA_MGR_SOCFPGA_A10)    +=
> > > socfpga-a10.o
> > > > >  obj-$(CONFIG_FPGA_MGR_TS73XX)          += ts73xx-fpga.o
> > > > >  obj-$(CONFIG_FPGA_MGR_XILINX_SPI)      += xilinx-spi.o
> > > > >  obj-$(CONFIG_FPGA_MGR_ZYNQ_FPGA)       += zynq-fpga.o
> > > > > +obj-$(CONFIG_FPGA_MGR_ZYNQMP_FPGA)     += zynqmp-fpga.o
> > > > >  obj-$(CONFIG_ALTERA_PR_IP_CORE)         += altera-pr-ip-core.o
> > > > >  obj-$(CONFIG_ALTERA_PR_IP_CORE_PLAT)    += altera-pr-ip-core-plat.o
> > > > >
> > > > > diff --git a/drivers/fpga/zynqmp-fpga.c
> > > > > b/drivers/fpga/zynqmp-fpga.c new file mode 100644 index
> > > > > 000000000000..2760d7e3872a
> > > > > --- /dev/null
> > > > > +++ b/drivers/fpga/zynqmp-fpga.c
> > > > > @@ -0,0 +1,159 @@
> > > > > +// SPDX-License-Identifier: GPL-2.0+
> > > > > +/*
> > > > > + * Copyright (C) 2018 Xilinx, Inc.
> > > > > + */
> > > > > +
> > > > > +#include <linux/dma-mapping.h>
> > > > > +#include <linux/fpga/fpga-mgr.h> #include <linux/io.h> #include
> > > > > +<linux/kernel.h> #include <linux/module.h> #include
> > > > > +<linux/of_address.h> #include <linux/string.h> #include
> > > > > +<linux/firmware/xlnx-zynqmp.h>
> > > > > +
> > > > > +/* Constant Definitions */
> > > > > +#define IXR_FPGA_DONE_MASK     0X00000008U
> > > > > +
> > > > > +/**
> > > > > + * struct zynqmp_fpga_priv - Private data structure
> > > > > + * @dev:       Device data structure
> > > > > + * @flags:     flags which is used to identify the bitfile type
> > > > > + */
> > > > > +struct zynqmp_fpga_priv {
> > > > > +       struct device *dev;
> > > > > +       u32 flags;
> > > > > +};
> > > > > +
> > > > > +static int zynqmp_fpga_ops_write_init(struct fpga_manager *mgr,
> > > > > +                                     struct fpga_image_info *info,
> > > > > +                                     const char *buf, size_t
> > > > > +size) {
> > > > > +       struct zynqmp_fpga_priv *priv;
> > > > > +
> > > > > +       priv = mgr->priv;
> > > > > +       priv->flags = info->flags;
> > > > > +
> > > > > +       return 0;
> > > > > +}
> > > > > +
> > > > > +static int zynqmp_fpga_ops_write(struct fpga_manager *mgr,
> > > > > +                                const char *buf, size_t size) {
> > > > > +       struct zynqmp_fpga_priv *priv;
> > > > > +       char *kbuf;
> > > > > +       dma_addr_t dma_addr;
> > > > > +       int ret;
> > > > > +       const struct zynqmp_eemi_ops *eemi_ops =
> > > > > +zynqmp_pm_get_eemi_ops();
> > > >
> > > > Reverse xmas-tree please, i.e. long lines first.
> > > >
> > > > > +
> > > > > +       if (!eemi_ops || !eemi_ops->fpga_load)
> > > > > +               return -ENXIO;
> > > > > +
> > > > > +       priv = mgr->priv;
> > > > > +
> > > > > +       kbuf = dma_alloc_coherent(priv->dev, size, &dma_addr,
> > > GFP_KERNEL);
> > > > > +       if (!kbuf)
> > > > > +               return -ENOMEM;
> > > > > +
> > > > > +       memcpy(kbuf, buf, size);
> > > > > +
> > > > > +       wmb(); /* ensure all writes are done before initiate FW
> > > > > + call */
> > > > > +
> > > > > +       ret = eemi_ops->fpga_load(dma_addr, size, priv->flags);
> > >
> > > Don't you have to do anything with the flags? Is it really just a
> > > pass-through of FPGA manager flags to eemi calls?
> > >
> > > Don't you want to make partial bitstreams e.g. use a flags value
> > > that you export in your firmware header (xlnx-zynqmp.h) and set
> > > those based on what flags get passed in, i.e. explicitely translate FPGA
> Manager flags to your firmware flags?
> >
> > At this point of time the firmware use Flag 0 for full Bitstream and 1 for partial
> bitstream loading.
> > So I have not doing any explicit translate FPGA Manager flags inside the
> driver.
> > Will document the flags info in xlnx-zynqmp.h
> 
> I think you should explicitely translate them, the fact that they happen to line
> up in the current implementation is somewhat of coincidence, and in future
> might break (since it's not really easy to to spot the dependency when
> refactoring).
> 
> Why don't you do something like:
> 
> #include <linux/firmware/xilinx-zynqmp.h>
> 
> [...]
> 
> eemi_flags = 0;
> 
> if (flags & FPGA_MGR_PARTIAL_RECONFIG)
> 	eemi_flags |= XILINX_ZYNQMP_PM_FPGA_PARTIAL;
> 
> eemi_ops->fpga_load(...., eemi_flags);
> 

Yes, I agree with you and it's sound good. Will fix in the next version.

Regards,
Navakishore.




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