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

["Gupta, Nipun" <nipun.gupta@amd.com>]

On 6/26/2023 4:09 PM, Abhijit Gangurde wrote:
> Provide driver flag which gives an option to map the cdx
> device resource before probing the device driver.
> Also, make rte_cdx_map_device() API as public to map
> device resource separately.
> 
> Signed-off-by: Abhijit Gangurde <abhijit.gangurde@amd.com>
> ---
>   drivers/bus/cdx/bus_cdx_driver.h | 26 ++---------------
>   drivers/bus/cdx/cdx.c            | 11 ++++---
>   drivers/bus/cdx/rte_bus_cdx.h    | 50 ++++++++++++++++++++++++++++++++
>   drivers/bus/cdx/version.map      | 11 +++++--
>   4 files changed, 69 insertions(+), 29 deletions(-)
>   create mode 100644 drivers/bus/cdx/rte_bus_cdx.h
> 
> diff --git a/drivers/bus/cdx/bus_cdx_driver.h b/drivers/bus/cdx/bus_cdx_driver.h
> index fcacdb5896..1571131417 100644
> --- a/drivers/bus/cdx/bus_cdx_driver.h
> +++ b/drivers/bus/cdx/bus_cdx_driver.h
> @@ -37,6 +37,9 @@ struct rte_cdx_bus;
>   static const char DRV_EXP_TAG(name, cdx_tbl_export)[] __rte_used = \
>   RTE_STR(table)
>   
> +/** Device needs resource mapping */
> +#define RTE_CDX_DRV_NEED_MAPPING 0x0001
> +
>   /**
>    * A structure describing an ID for a CDX driver. Each driver provides a
>    * table of these IDs for each device that it supports.
> @@ -107,29 +110,6 @@ struct rte_cdx_driver {
>   	uint32_t drv_flags;			/**< Flags RTE_CDX_DRV_*. */
>   };
>   
> -/**
> - * Map the CDX device resources in user space virtual memory address.
> - *
> - * @param dev
> - *   A pointer to a rte_cdx_device structure describing the device
> - *   to use.
> - *
> - * @return
> - *   0 on success, <0 on error.
> - */
> -__rte_internal
> -int rte_cdx_map_device(struct rte_cdx_device *dev);
> -
> -/**
> - * Unmap this device.
> - *
> - * @param dev
> - *   A pointer to a rte_cdx_device structure describing the device
> - *   to use.
> - */
> -__rte_internal
> -void rte_cdx_unmap_device(struct rte_cdx_device *dev);
> -
>   /**
>    * Register a CDX driver.
>    *
> diff --git a/drivers/bus/cdx/cdx.c b/drivers/bus/cdx/cdx.c
> index 28bbf92ed5..47dc4eabe7 100644
> --- a/drivers/bus/cdx/cdx.c
> +++ b/drivers/bus/cdx/cdx.c
> @@ -74,6 +74,7 @@
>   #include <rte_kvargs.h>
>   #include <rte_malloc.h>
>   #include <rte_vfio.h>
> +#include <rte_bus_cdx.h>
>   
>   #include <eal_filesystem.h>
>   
> @@ -380,10 +381,12 @@ 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..b9280b5f7f
> --- /dev/null
> +++ b/drivers/bus/cdx/rte_bus_cdx.h
> @@ -0,0 +1,50 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright (C) 2023, Advanced Micro Devices, Inc.
> + */
> +
> +#ifndef _RTE_BUS_CDX_H_
> +#define _RTE_BUS_CDX_H_

nit: there are no underscores before or after in other cdx header files. 
please change to 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

nit: all doxygen comments should end with a dot.

> + *
> + * 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.
> + *
> + * @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.
> + */
> +int rte_cdx_map_device(struct rte_cdx_device *dev);
> +
> +/**
> + * Unmap this device
> + *
> + * @param dev
> + *   A pointer to a rte_cdx_device structure describing the device
> + *   to use
> + */
> +void rte_cdx_unmap_device(struct rte_cdx_device *dev);
> +
> +#ifdef __cplusplus
> +}
> +#endif
> +
> +#endif /* _RTE_BUS_CDX_H_ */
> diff --git a/drivers/bus/cdx/version.map b/drivers/bus/cdx/version.map
> index 0a15d39ae8..cc7b1f821b 100644
> --- a/drivers/bus/cdx/version.map
> +++ b/drivers/bus/cdx/version.map
> @@ -1,9 +1,16 @@
> -INTERNAL {
> +DPDK_23 {
>   	global:
>   
>   	rte_cdx_map_device;
> -	rte_cdx_register;
>   	rte_cdx_unmap_device;
> +
> +	local: *;
> +};
> +
> +INTERNAL {
> +	global:
> +
> +	rte_cdx_register;
>   	rte_cdx_unregister;
>   	rte_cdx_vfio_intr_disable;
>   	rte_cdx_vfio_intr_enable;