Re: [PATCH v3] bus/cdx: provide driver flag for optional resource mapping

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

On Tue, Jul 11, 2023 at 7:52 AM Abhijit Gangurde
<abhijit.gangurde@amd.com> wrote:
> @@ -383,10 +384,12 @@ cdx_probe_one_driver(struct rte_cdx_driver *dr,
>         CDX_BUS_DEBUG("  probe device %s using driver: %s", dev_name,
>                 dr->driver.name);
>
> -       ret = cdx_vfio_map_resource(dev);
> -       if (ret != 0) {
> -               CDX_BUS_ERR("CDX map device failed: %d", ret);
> -               goto error_map_device;
> +       if (dr->drv_flags & RTE_CDX_DRV_NEED_MAPPING) {
> +               ret = cdx_vfio_map_resource(dev);
> +               if (ret != 0) {
> +                       CDX_BUS_ERR("CDX map device failed: %d", ret);
> +                       goto error_map_device;
> +               }
>         }
>
>         /* call the driver probe() function */
> diff --git a/drivers/bus/cdx/rte_bus_cdx.h b/drivers/bus/cdx/rte_bus_cdx.h
> new file mode 100644
> index 0000000000..4ca12f90c4
> --- /dev/null
> +++ b/drivers/bus/cdx/rte_bus_cdx.h
> @@ -0,0 +1,52 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright (C) 2023, Advanced Micro Devices, Inc.
> + */
> +
> +#ifndef RTE_BUS_CDX_H
> +#define RTE_BUS_CDX_H
> +
> +/**
> + * @file
> + * CDX device & driver interface
> + */
> +
> +#ifdef __cplusplus
> +extern "C" {
> +#endif
> +
> +/* Forward declarations */
> +struct rte_cdx_device;
> +
> +/**
> + * Map the CDX device resources in user space virtual memory address.
> + *
> + * Note that driver should not call this function when flag
> + * RTE_CDX_DRV_NEED_MAPPING is set, as EAL will do that for
> + * you when it's on.

Why should we export this function in the application ABI, if it is
only used by drivers?


> + *
> + * @param dev
> + *   A pointer to a rte_cdx_device structure describing the device
> + *   to use.
> + *
> + * @return
> + *   0 on success, negative on error and positive if no driver
> + *   is found for the device.
> + */
> +__rte_experimental
> +int rte_cdx_map_device(struct rte_cdx_device *dev);
>


-- 
David Marchand