Re: [PATCH v2] bus: add platform bus

[David Marchand <david.marchand@redhat.com>]

On Sun, Feb 5, 2023 at 7:39 PM Tomasz Duszynski <tduszynski@marvell.com> wrote:
>
> Platform bus is a software bus under Linux that manages devices which
> generally do not have built-in discovery mechanisms. Linux normally
> learns about platform devices directly from device-tree during
> boot-up phase.
>
> Up to this point, whenever some userspace app needed control over
> platform device or a range of thereof some sort of driver being
> a mixture of vdev/rawdev was required.
>
> In order to simplify this task, provide an auto-probe
> experience and separate bus logic from the driver itself,
> add platform bus support.
>
> Currently devices backed up by vfio-platform kernel driver
> are supported.
>
> Signed-off-by: Tomasz Duszynski <tduszynski@marvell.com>
> ---
> v2:
> - take a step back and do not add eal changes that simplify parsing
>   sysfs string. That should be moved to a more generic library and
>   submitted separately.
> - compile code conditionally based on VFIO_PRESENT

I must be missing something, but in the form proposed in v2, this
won't work, see below.

[snip]


> diff --git a/drivers/bus/platform/platform.c b/drivers/bus/platform/platform.c
> new file mode 100644
> index 0000000000..9f06327b77
> --- /dev/null
> +++ b/drivers/bus/platform/platform.c
> @@ -0,0 +1,632 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright(C) 2023 Marvell.
> + */
> +
> +#ifdef VFIO_PRESENT
> +

VFIO_PRESENT is defined in rte_vfio.h and nothing else defines it.
So the rest of this file is a noop.
What did I miss?

So either you need to include <rte_vfio.h> first, or we could move the
VFIO_PRESENT detection stuff from this EAL header, to meson.


I did not look further into this patch, since this added code is
probably not tested (since not compiled).


-- 
David Marchand