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

[Nava kishore Manne <navam@xilinx.com>]

Hi,

> -----Original Message-----
> From: Moritz Fischer <mdf@kernel.org>
> Sent: Thursday, January 28, 2021 3:15 AM
> To: Michal Simek <michals@xilinx.com>
> Cc: Nava kishore Manne <navam@xilinx.com>; Moritz Fischer
> <mdf@kernel.org>; trix@redhat.com; robh+dt@kernel.org; linux-
> fpga@vger.kernel.org; devicetree@vger.kernel.org; linux-arm-
> kernel@lists.infradead.org; linux-kernel@vger.kernel.org; git
> <git@xilinx.com>; chinnikishore369@gmail.com; Appana Durga Kedareswara
> Rao <appanad@xilinx.com>
> Subject: Re: [PATCH 3/3] fpga: versal-fpga: Add versal fpga manager driver
> 
> On Wed, Jan 27, 2021 at 10:16:32AM +0100, Michal Simek wrote:
> > Hi
> >
> > On 1/27/21 9:57 AM, Nava kishore Manne wrote:
> > > Hi Moritz,
> > >
> > > 	Please find my response inline.
> > >
> > >> -----Original Message-----
> > >> From: Moritz Fischer <mdf@kernel.org>
> > >> Sent: Sunday, January 24, 2021 5:04 AM
> > >> To: Nava kishore Manne <navam@xilinx.com>
> > >> Cc: Moritz Fischer <mdf@kernel.org>; trix@redhat.com;
> > >> robh+dt@kernel.org; Michal Simek <michals@xilinx.com>; linux-
> > >> fpga@vger.kernel.org; devicetree@vger.kernel.org; linux-arm-
> > >> kernel@lists.infradead.org; linux-kernel@vger.kernel.org; git
> > >> <git@xilinx.com>; chinnikishore369@gmail.com; Appana Durga
> > >> Kedareswara Rao <appanad@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@kernel.org>
> > >>>> Sent: Tuesday, January 19, 2021 6:03 AM
> > >>>> To: Nava kishore Manne <navam@xilinx.com>
> > >>>> Cc: mdf@kernel.org; trix@redhat.com; robh+dt@kernel.org; Michal
> > >>>> Simek <michals@xilinx.com>; linux-fpga@vger.kernel.org;
> > >>>> devicetree@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
> > >>>> linux- kernel@vger.kernel.org; git <git@xilinx.com>;
> > >>>> chinnikishore369@gmail.com; Appana Durga Kedareswara Rao
> > >>>> <appanad@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@xilinx.com>
> > >>>>> Signed-off-by: Nava kishore Manne <nava.manne@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.
> >
> > Look at PDI as ps7_init/psu_init file but in different format. And
> > bitstream is optional part of it (like a one partition).
> 
> So at that point I could still have no bitstream loaded (optional), and my
> status would be 'unknown' not 'operating' if I cannot tell the two cases apart.
> What am I missing? :)
> 

Agree, In few cases Bitstream partition is optional, So we can't say exactly whether the PL is having Bitstream or Not . So here the ideal default PL state should be Unknown.
Will fix in v2.

Regards,
Navakishore.