Subject: Re: [PATCH v5 26/27] cxl: add function for obtaining params from a region

From: Zhi Wang <[email-masked]>
Date: Tue, 19 Nov 2024 22:40:18 +0200

On Mon, 18 Nov 2024 16:44:33 +0000
<[email-masked]> wrote:

LGTM. Reviewed-by: Zhi Wang <[email-masked]>

> From: Alejandro Lucero <[email-masked]>
> 
> A CXL region struct contains the physical address to work with.
> 
> Add a function for given a opaque cxl region struct returns the params
> to be used for mapping such memory range.
> 
> Signed-off-by: Alejandro Lucero <[email-masked]>
> ---
>  drivers/cxl/core/region.c | 16 ++++++++++++++++
>  drivers/cxl/cxl.h         |  2 ++
>  include/cxl/cxl.h         |  2 ++
>  3 files changed, 20 insertions(+)
> 
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index eff3ad788077..fa44a60549f7 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -2663,6 +2663,22 @@ static struct cxl_region *devm_cxl_add_region(struct cxl_root_decoder *cxlrd,
>  	return ERR_PTR(rc);
>  }
>  
> +int cxl_get_region_params(struct cxl_region *region, resource_size_t *start,
> +			  resource_size_t *end)
> +{
> +	if (!region)
> +		return -ENODEV;
> +
> +	if (!region->params.res)
> +		return -ENOSPC;
> +
> +	*start = region->params.res->start;
> +	*end = region->params.res->end;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_NS_GPL(cxl_get_region_params, 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 ee3385db5663..7b46d313e581 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -913,6 +913,8 @@ void cxl_coordinates_combine(struct access_coordinate *out,
>  
>  bool cxl_endpoint_decoder_reset_detected(struct cxl_port *port);
>  
> +int cxl_get_region_params(struct cxl_region *region, resource_size_t *start,
> +			  resource_size_t *end);
>  /*
>   * 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 2a8ebabfc1dd..f14a3f292ad8 100644
> --- a/include/cxl/cxl.h
> +++ b/include/cxl/cxl.h
> @@ -77,4 +77,6 @@ struct cxl_region *cxl_create_region(struct cxl_root_decoder *cxlrd,
>  				     bool avoid_dax);
>  
>  int cxl_accel_region_detach(struct cxl_endpoint_decoder *cxled);
> +int cxl_get_region_params(struct cxl_region *region, resource_size_t *start,
> +			  resource_size_t *end);
>  #endif