Re: [PATCH v9 1/2] uio: uio_dfl: add userspace i/o driver for DFL bus

[Tom Rix]

On 1/25/21 12:49 AM, Xu Yilun wrote:
> This patch supports the DFL drivers be written in userspace. This is
> realized by exposing the userspace I/O device interfaces.
>
> The driver now only binds the ether group feature, which has no irq. So
> the irq support is not implemented yet.
>
> Signed-off-by: Xu Yilun <yilun.xu@xxxxxxxxx>
> ---
> v9: switch to add a uio driver in drivers/uio
> ---
>  drivers/uio/Kconfig   | 13 ++++++++++
>  drivers/uio/Makefile  |  1 +
>  drivers/uio/uio_dfl.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++

You should add this to the MAINTAINERS file.

>  3 files changed, 80 insertions(+)
>  create mode 100644 drivers/uio/uio_dfl.c
>
> diff --git a/drivers/uio/Kconfig b/drivers/uio/Kconfig
> index 202ee81..44778f8 100644
> --- a/drivers/uio/Kconfig
> +++ b/drivers/uio/Kconfig
> @@ -165,4 +165,17 @@ config UIO_HV_GENERIC
>  	  to network and storage devices from userspace.
>  
>  	  If you compile this as a module, it will be called uio_hv_generic.
> +
> +config UIO_DFL
> +	tristate "Generic driver for DFL bus"

The term 'DFL' will be unknown to folks in drivers/uio

I think it would be better if DFL was always prefixed 'FPGA DFL'

> +	depends on FPGA_DFL
> +	help
> +	  Generic DFL (Device Feature List) driver for Userspace I/O devices.
> +	  It is useful to provide direct access to DFL devices from userspace.
> +	  A sample userspace application using this driver is available for
> +	  download in a git repository:
> +
> +	    git clone https://github.com/OPAE/opae-sdk.git
> +
> +	  If you compile this as a module, it will be called uio_dfl.

opae-sdk is pretty large and uncovered in the Documentation/fpga/dfl.rst.

Where in opae-sdk is this example ?

If you can point me at the example, I will turn it into a selftest.

Tom

>  endif
> diff --git a/drivers/uio/Makefile b/drivers/uio/Makefile
> index c285dd2..f2f416a1 100644
> --- a/drivers/uio/Makefile
> +++ b/drivers/uio/Makefile
> @@ -11,3 +11,4 @@ obj-$(CONFIG_UIO_PRUSS)         += uio_pruss.o
>  obj-$(CONFIG_UIO_MF624)         += uio_mf624.o
>  obj-$(CONFIG_UIO_FSL_ELBC_GPCM)	+= uio_fsl_elbc_gpcm.o
>  obj-$(CONFIG_UIO_HV_GENERIC)	+= uio_hv_generic.o
> +obj-$(CONFIG_UIO_DFL)	+= uio_dfl.o
> diff --git a/drivers/uio/uio_dfl.c b/drivers/uio/uio_dfl.c
> new file mode 100644
> index 0000000..89c0fc7
> --- /dev/null
> +++ b/drivers/uio/uio_dfl.c
> @@ -0,0 +1,66 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Generic DFL driver for Userspace I/O devicess
> + *
> + * Copyright (C) 2021 Intel Corporation, Inc.
> + */
> +#include <linux/dfl.h>
> +#include <linux/errno.h>
> +#include <linux/module.h>
> +#include <linux/uio_driver.h>
> +
> +#define DRIVER_NAME "uio_dfl"
> +
> +static int uio_dfl_probe(struct dfl_device *ddev)
> +{
> +	struct resource *r = &ddev->mmio_res;
> +	struct device *dev = &ddev->dev;
> +	struct uio_info *uioinfo;
> +	struct uio_mem *uiomem;
> +	int ret;
> +
> +	uioinfo = devm_kzalloc(dev, sizeof(struct uio_info), GFP_KERNEL);
> +	if (!uioinfo)
> +		return -ENOMEM;
> +
> +	uioinfo->name = DRIVER_NAME;
> +	uioinfo->version = "0";
> +
> +	uiomem = &uioinfo->mem[0];
> +	uiomem->memtype = UIO_MEM_PHYS;
> +	uiomem->addr = r->start & PAGE_MASK;
> +	uiomem->offs = r->start & ~PAGE_MASK;
> +	uiomem->size = (uiomem->offs + resource_size(r)
> +			+ PAGE_SIZE - 1) & PAGE_MASK;
> +	uiomem->name = r->name;
> +
> +	/* Irq is yet to be supported */
> +	uioinfo->irq = UIO_IRQ_NONE;
> +
> +	ret = devm_uio_register_device(dev, uioinfo);
> +	if (ret)
> +		dev_err(dev, "unable to register uio device\n");
> +
> +	return ret;
> +}
> +
> +#define FME_FEATURE_ID_ETH_GROUP	0x10
> +
> +static const struct dfl_device_id uio_dfl_ids[] = {
> +	{ FME_ID, FME_FEATURE_ID_ETH_GROUP },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(dfl, uio_dfl_ids);
> +
> +static struct dfl_driver uio_dfl_driver = {
> +	.drv = {
> +		.name = DRIVER_NAME,
> +	},
> +	.id_table	= uio_dfl_ids,
> +	.probe		= uio_dfl_probe,
> +};
> +module_dfl_driver(uio_dfl_driver);
> +
> +MODULE_DESCRIPTION("Generic DFL driver for Userspace I/O devices");
> +MODULE_AUTHOR("Intel Corporation");
> +MODULE_LICENSE("GPL v2");