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

[Moritz Fischer]

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
> 
> PDI source type can be DDR, OCM, QSPI flash etc..
No idea what PDI is :)
> But driver allocates memory always from DDR, Since driver supports only
> DDR source type.
> 
> Signed-off-by: Appana Durga Kedareswara rao <appana.durga.rao@xxxxxxxxxx>
> Signed-off-by: Nava kishore Manne <nava.manne@xxxxxxxxxx>
> ---
>  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.
> +};
> +
> +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.
> +
> +	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?
> +}
> +
> +static const struct fpga_manager_ops versal_fpga_ops = {
> +	.state = versal_fpga_ops_state,
> +	.write_init = versal_fpga_ops_write_init,
> +	.write = versal_fpga_ops_write,
> +	.write_complete = versal_fpga_ops_write_complete,
> +};
> +
> +static int versal_fpga_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct versal_fpga_priv *priv;
> +	struct fpga_manager *mgr;
> +	int err, ret;
Please pick one, err or ret. 'err' seems unused?
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->dev = dev;
> +	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
> +	if (ret < 0) {
> +		dev_err(dev, "no usable DMA configuration");
Nit: "no usable DMA configuration\n"
> +		return ret;
> +	}
> +
> +	mgr = devm_fpga_mgr_create(dev, "Xilinx Versal FPGA Manager",
> +				   &versal_fpga_ops, priv);
> +	if (!mgr)
> +		return -ENOMEM;
> +
> +	platform_set_drvdata(pdev, mgr);
> +

Replace this part:
> +	err = fpga_mgr_register(mgr);
> +	if (err) {
> +		dev_err(dev, "unable to register FPGA manager");
> +		fpga_mgr_free(mgr);
> +		return err;
> +	}

with:
	return devm_fpga_mgr_register(mgr);

I tried to get rid of the boilerplate, since every driver repeats it
(and above calling fpga_mgr_free(mgr) on a devm_fpga_mgr_create()
created FPGA manager is wrong?) :)
> +
> +	return 0;
> +}
> +

Then
> +static int versal_fpga_remove(struct platform_device *pdev)
> +{
> +	struct fpga_manager *mgr = platform_get_drvdata(pdev);
> +
> +	fpga_mgr_unregister(mgr);
> +	fpga_mgr_free(mgr);
> +
> +	return 0;
> +}
drop this since cleanup is now automatic.
> +
> +static const struct of_device_id versal_fpga_of_match[] = {
> +	{ .compatible = "xlnx,versal-fpga", },
> +	{},
> +};
> +
Nit: Drop the newline
> +MODULE_DEVICE_TABLE(of, versal_fpga_of_match);
> +
> +static struct platform_driver versal_fpga_driver = {
> +	.probe = versal_fpga_probe,
> +	.remove = versal_fpga_remove,
> +	.driver = {
> +		.name = "versal_fpga_manager",
> +		.of_match_table = of_match_ptr(versal_fpga_of_match),
> +	},
> +};
> +
Nit: Drop the newline
> +module_platform_driver(versal_fpga_driver);
> +
> +MODULE_AUTHOR("Nava kishore Manne <nava.manne@xxxxxxxxxx>");
> +MODULE_AUTHOR("Appana Durga Kedareswara rao <appanad.durga.rao@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("Xilinx Versal FPGA Manager");
> +MODULE_LICENSE("GPL");
> -- 
> 2.18.0
> 
Thanks,
Moritz