Re: [PATCH v2] cdx: add support for bus mastering

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, Jul 21, 2023 at 05:16:22PM +0530, Nipun Gupta wrote:
> Introduce cdx_set_master() and cdx_clear_master() APIs to support
> enable and disable of bus mastering. Drivers need to use these APIs to
> enable/disable DMAs from the CDX devices.
> 
> Signed-off-by: Nipun Gupta <nipun.gupta@amd.com>
> Reviewed-by: Pieter Jansen van Vuuren <pieter.jansen-van-vuuren@amd.com>
> ---
> 
> Changes v1->v2:
> - Replace bme with bus_master_enable
> - Added check for dev_configure API callback
> - remove un-necessary error prints
> - changed conditional to if-else
> - updated commit message to use 72 columns
> 
>  drivers/cdx/cdx.c                       | 29 +++++++++++++
>  drivers/cdx/controller/cdx_controller.c |  4 ++
>  drivers/cdx/controller/mcdi_functions.c | 58 +++++++++++++++++++++++++
>  drivers/cdx/controller/mcdi_functions.h | 13 ++++++
>  include/linux/cdx/cdx_bus.h             | 16 +++++++
>  5 files changed, 120 insertions(+)
> 
> diff --git a/drivers/cdx/cdx.c b/drivers/cdx/cdx.c
> index d2cad4c670a0..71ddb56a5d08 100644
> --- a/drivers/cdx/cdx.c
> +++ b/drivers/cdx/cdx.c
> @@ -182,6 +182,35 @@ cdx_match_id(const struct cdx_device_id *ids, struct cdx_device *dev)
>  	return NULL;
>  }
>  
> +int cdx_set_master(struct cdx_device *cdx_dev)
> +{
> +	struct cdx_controller *cdx = cdx_dev->cdx;
> +	struct cdx_device_config dev_config;
> +	int ret = EOPNOTSUPP;

"-EOPNOTSUP"