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

From: Alejandro Lucero Palau <[email-masked]>
Date: Wed, 27 Nov 2024 17:12:10 +0000

On 11/21/24 16:31, Dave Jiang wrote:
>
> On 11/18/24 9:44 AM, [email-masked] wrote:
>> 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)
> Maybe just pass in a 'struct range' ptr and call it cxl_get_region_range()?

That makes sense, and that solves the problem raised by Allison.

Thanks

> DJ
>
>> +{
>> +	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