Re: [PATCH v11 21/23] cxl: add function for obtaining region range

[Ben Cheatham <benjamin.cheatham@amd.com>]

On 3/10/25 4:03 PM, alejandro.lucero-palau@amd.com wrote:
> From: Alejandro Lucero <alucerop@amd.com>
> 
> A CXL region struct contains the physical address to work with.
> 
> Add a function for getting the cxl region range to be used for mapping
> such memory range.
> 
> Signed-off-by: Alejandro Lucero <alucerop@amd.com>
> Reviewed-by: Zhi Wang <zhiw@nvidia.com>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> ---
>  drivers/cxl/core/region.c | 15 +++++++++++++++
>  drivers/cxl/cxl.h         |  1 +
>  include/cxl/cxl.h         |  2 ++
>  3 files changed, 18 insertions(+)
> 
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 7f832cb1db51..0c85245c2407 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -2716,6 +2716,21 @@ static struct cxl_region *devm_cxl_add_region(struct cxl_root_decoder *cxlrd,
>  	return ERR_PTR(rc);
>  }
>  
> +int cxl_get_region_range(struct cxl_region *region, struct range *range)
> +{
> +	if (WARN_ON_ONCE(!region))
> +		return -ENODEV;
> +
> +	if (!region->params.res)
> +		return -ENOSPC;
> +
> +	range->start = region->params.res->start;
> +	range->end = region->params.res->end;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_NS_GPL(cxl_get_region_range, "CXL");
> +
>  static ssize_t __create_region_show(struct cxl_root_decoder *cxlrd, char *buf)
>  {
>  	return sysfs_emit(buf, "region%u\n", atomic_read(&cxlrd->region_id));
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 2eb927c9229c..953af2b31b1c 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -811,6 +811,7 @@ void cxl_coordinates_combine(struct access_coordinate *out,
>  
>  bool cxl_endpoint_decoder_reset_detected(struct cxl_port *port);
>  
> +int cxl_get_region_range(struct cxl_region *region, struct range *range);

I don't think this needs to be declared in drivers/cxl/cxl.h since it'll
get defined when including include/cxl/cxl.h.

>  /*
>   * Unit test builds overrides this to __weak, find the 'strong' version
>   * of these symbols in tools/testing/cxl/.
> diff --git a/include/cxl/cxl.h b/include/cxl/cxl.h
> index f54d8c72bc79..8eb918241c48 100644
> --- a/include/cxl/cxl.h
> +++ b/include/cxl/cxl.h
> @@ -264,4 +264,6 @@ struct cxl_region *cxl_create_region(struct cxl_root_decoder *cxlrd,
>  				     bool no_dax);
>  
>  int cxl_accel_region_detach(struct cxl_endpoint_decoder *cxled);
> +struct range;
> +int cxl_get_region_range(struct cxl_region *region, struct range *range);
>  #endif