linux/igb_uio: add Makefile to build the kernel module

  With DPDK 20.11 release, the igb_uio module is no more part of DPDK.
There are use cases where this module is required, for example while
testing the virtual ports in OvS, the virtual ports are bound to
igb_uio module inside a VM. So, this patch provides a Makefile
which can be used to build this module and use as needed.

Before building this module, the user is expected to build the
DPDK using meson build system and make sure that the required
libraries are installed in the path /usr/local

Signed-off-by: Hariprasad Govindharajan <hariprasad.govindharajan@intel.com>
---
 linux/igb_uio/Makefile | 8 ++++++++
 1 file changed, 8 insertions(+)
 create mode 100644 linux/igb_uio/Makefile
  

On 10/5/2020 3:47 PM, Hariprasad Govindharajan wrote:
> With DPDK 20.11 release, the igb_uio module is no more part of DPDK.
> There are use cases where this module is required, for example while
> testing the virtual ports in OvS, the virtual ports are bound to
> igb_uio module inside a VM. So, this patch provides a Makefile
> which can be used to build this module and use as needed.
> 
> Before building this module, the user is expected to build the
> DPDK using meson build system and make sure that the required
> libraries are installed in the path /usr/local
> 

Can you please highlight in the commit log that this is for the dpdk-kmods repo:
https://git.dpdk.org/dpdk-kmods/

> Signed-off-by: Hariprasad Govindharajan <hariprasad.govindharajan@intel.com>
> ---
>   linux/igb_uio/Makefile | 8 ++++++++
>   1 file changed, 8 insertions(+)
>   create mode 100644 linux/igb_uio/Makefile
> 
> diff --git a/linux/igb_uio/Makefile b/linux/igb_uio/Makefile
> new file mode 100644
> index 0000000..be39131
> --- /dev/null
> +++ b/linux/igb_uio/Makefile
> @@ -0,0 +1,8 @@
> +obj-m += igb_uio.o

I think we can drop this from this makefile, it is in Kbuild

> +DPDK_INSTALL=/usr/local/include

Can we use "?=" assignment to accept user provided value

Also since it points the header folder, what do you think about changing the 
macro name to highlight that it is for headers folder?

> +
> +all:
> +		make EXTRA_CFLAGS="-I $(DPDK_INSTALL)" -C /lib/modules/`uname -r`/build/ M=$(PWD)

Same for the kernel path, can you make it variable to user can override?

> +
> +clean:
> +	    make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean
>