[PATCH 3/3] fpga: versal-fpga: Add versal fpga manager driver

[Nava kishore Manne]

Hi Moritz,

	Please find my response inline.

> -----Original Message-----
> From: Moritz Fischer <mdf at kernel.org>
> Sent: Sunday, January 24, 2021 5:04 AM
> To: Nava kishore Manne <navam at xilinx.com>
> Cc: Moritz Fischer <mdf at kernel.org>; trix at redhat.com;
> robh+dt at kernel.org; Michal Simek <michals at xilinx.com>; linux-
> fpga at vger.kernel.org; devicetree at vger.kernel.org; linux-arm-
> kernel at lists.infradead.org; linux-kernel at vger.kernel.org; git
> <git at xilinx.com>; chinnikishore369 at gmail.com; Appana Durga Kedareswara
> Rao <appanad at xilinx.com>
> Subject: Re: [PATCH 3/3] fpga: versal-fpga: Add versal fpga manager driver
> 
> Hi Nava,
> 
> On Fri, Jan 22, 2021 at 10:34:15AM +0000, Nava kishore Manne wrote:
> > Hi Moritz,
> >
> > 	Thanks for the review.
> > Please find my response inline.
> >
> > > -----Original Message-----
> > > From: Moritz Fischer <mdf at kernel.org>
> > > Sent: Tuesday, January 19, 2021 6:03 AM
> > > To: Nava kishore Manne <navam at xilinx.com>
> > > Cc: mdf at kernel.org; trix at redhat.com; robh+dt at kernel.org; Michal
> > > Simek <michals at xilinx.com>; linux-fpga at vger.kernel.org;
> > > devicetree at vger.kernel.org; linux-arm-kernel at lists.infradead.org;
> > > linux- kernel at vger.kernel.org; git <git at xilinx.com>;
> > > chinnikishore369 at gmail.com; Appana Durga Kedareswara Rao
> > > <appanad at xilinx.com>
> > > Subject: Re: [PATCH 3/3] fpga: versal-fpga: Add versal fpga manager
> > > driver
> > >
> > > Hi Nava,
> > >
> > > On Mon, Jan 18, 2021 at 08:13:18AM +0530, Nava kishore Manne wrote:
> > > > This patch adds driver for versal fpga manager.
> > > Nit: Add support for Xilinx Versal FPGA manager
> >
> > Will fix in v2.
> >
> > > >
> > > > PDI source type can be DDR, OCM, QSPI flash etc..
> > > No idea what PDI is :)
> >
> > Programmable device image (PDI).
> > This file is generated by Xilinx Vivado tool and it contains configuration data
> objects.
> >
> > > > But driver allocates memory always from DDR, Since driver supports
> > > > only DDR source type.
> > > >
> > > > Signed-off-by: Appana Durga Kedareswara rao
> > > > <appana.durga.rao at xilinx.com>
> > > > Signed-off-by: Nava kishore Manne <nava.manne at xilinx.com>
> > > > ---
> > > >  drivers/fpga/Kconfig       |   8 ++
> > > >  drivers/fpga/Makefile      |   1 +
> > > >  drivers/fpga/versal-fpga.c | 149
> > > > +++++++++++++++++++++++++++++++++++++
> > > >  3 files changed, 158 insertions(+)  create mode 100644
> > > > drivers/fpga/versal-fpga.c
> > > >
> > > > diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig index
> > > > 5645226ca3ce..9f779c3a6739 100644
> > > > --- a/drivers/fpga/Kconfig
> > > > +++ b/drivers/fpga/Kconfig
> > > > @@ -216,4 +216,12 @@ config FPGA_MGR_ZYNQMP_FPGA
> > > >  	  to configure the programmable logic(PL) through PS
> > > >  	  on ZynqMP SoC.
> > > >
> > > > +config FPGA_MGR_VERSAL_FPGA
> > > > +        tristate "Xilinx Versal FPGA"
> > > > +        depends on ARCH_ZYNQMP || COMPILE_TEST
> > > > +        help
> > > > +          Select this option to enable FPGA manager driver support for
> > > > +          Xilinx Versal SOC. This driver uses the versal soc firmware
> > > > +          interface to load programmable logic(PL) images
> > > > +          on versal soc.
> > > >  endif # FPGA
> > > > diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile index
> > > > d8e21dfc6778..40c9adb6a644 100644
> > > > --- a/drivers/fpga/Makefile
> > > > +++ b/drivers/fpga/Makefile
> > > > @@ -18,6 +18,7 @@ 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-$(CONFIG_FPGA_MGR_VERSAL_FPGA)      += versal-fpga.o
> > > >  obj-$(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/versal-fpga.c
> > > > b/drivers/fpga/versal-fpga.c new file mode 100644 index
> > > > 000000000000..2a42aa78b182
> > > > --- /dev/null
> > > > +++ b/drivers/fpga/versal-fpga.c
> > > > @@ -0,0 +1,149 @@
> > > > +// SPDX-License-Identifier: GPL-2.0+
> > > > +/*
> > > > + * Copyright (C) 2021 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 PDI_SOURCE_TYPE	0xF
> > > > +
> > > > +/**
> > > > + * struct versal_fpga_priv - Private data structure
> > > > + * @dev:	Device data structure
> > > > + * @flags:	flags which is used to identify the PL Image type
> > > > + */
> > > > +struct versal_fpga_priv {
> > > > +	struct device *dev;
> > > > +	u32 flags;
> > > This seems unused ... please introduce them when/if you start using
> them.
> >
> > Will fix in v2.
> >
> > > > +};
> > > > +
> > > > +static int versal_fpga_ops_write_init(struct fpga_manager *mgr,
> > > > +				      struct fpga_image_info *info,
> > > > +				      const char *buf, size_t size) {
> > > > +	struct versal_fpga_priv *priv;
> > > > +
> > > > +	priv = mgr->priv;
> > > > +	priv->flags = info->flags;
> > > ? What uses this ? It seems this function could just be 'return 0' right now.
> >
> > Will fix in v2.
> >
> > > > +
> > > > +	return 0;
> > > > +}
> > > > +
> > > > +static int versal_fpga_ops_write(struct fpga_manager *mgr,
> > > > +				 const char *buf, size_t size) {
> > > > +	struct versal_fpga_priv *priv;
> > > > +	dma_addr_t dma_addr = 0;
> > > > +	char *kbuf;
> > > > +	int ret;
> > > > +
> > > > +	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 = zynqmp_pm_load_pdi(PDI_SOURCE_TYPE, dma_addr);
> > > > +
> > > > +	dma_free_coherent(priv->dev, size, kbuf, dma_addr);
> > > > +
> > > > +	return ret;
> > > > +}
> > > > +
> > > > +static int versal_fpga_ops_write_complete(struct fpga_manager *mgr,
> > > > +					  struct fpga_image_info *info) {
> > > > +	return 0;
> > > > +}
> > > > +
> > > > +static enum fpga_mgr_states versal_fpga_ops_state(struct
> > > > +fpga_manager
> > > > +*mgr) {
> > > > +	return FPGA_MGR_STATE_OPERATING;
> > > Is that always the case? Shouldn't that be
> FPGA_MGR_STATE_UNKNOWN?
> >
> > For Versal SoC base PDI is always configured prior to Linux boot up. So I
> make the fpga state as OPERATING.
> > Please let know if it is not a proper implementation will think about the
> alternate solution.
> 
> So you're saying I can't boot a Versal SoC without a PDI / Bitstream loaded?
> Interesting :)
> >

For Versal SoC Vivado generated base PDI is always needed to bring-up the board. 

Regards,
Navakishore.