RE: [RFC PATCH v2 04/20] cxl/mbox: Add GET_FEATURE mailbox command

[Shiju Jose <shiju.jose@huawei.com>]

>-----Original Message-----
>From: Dan Williams <dan.j.williams@intel.com>
>Sent: 06 December 2024 00:44
>To: Dave Jiang <dave.jiang@intel.com>; linux-cxl@vger.kernel.org
>Cc: dan.j.williams@intel.com; ira.weiny@intel.com; vishal.l.verma@intel.com;
>alison.schofield@intel.com; Jonathan Cameron
><jonathan.cameron@huawei.com>; dave@stgolabs.net; jgg@nvidia.com; Shiju
>Jose <shiju.jose@huawei.com>
>Subject: Re: [RFC PATCH v2 04/20] cxl/mbox: Add GET_FEATURE mailbox
>command
>
>Dave Jiang wrote:
>> From: Shiju Jose <shiju.jose@huawei.com>
>>
>> Add support for GET_FEATURE mailbox command.
>>
>> CXL spec 3.1 section 8.2.9.6 describes optional device specific features.
>> The settings of a feature can be retrieved using Get Feature command.
>> CXL spec 3.1 section 8.2.9.6.2 describes Get Feature command.
>>
>> Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
>> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
>> ---
>> This patch is not needed by this series except the opcode enumeration.
>> ---
>
>Wait, then why is it included?
>
>I would say fold the small bit that you need into the previous patch, especially if
>we think that fwctl can cover all the "get feature" use cases.
>
>>  drivers/cxl/core/mbox.c | 41
>+++++++++++++++++++++++++++++++++++++++++
>>  drivers/cxl/cxlmem.h    | 26 ++++++++++++++++++++++++++
>>  2 files changed, 67 insertions(+)
>>
>> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c index
>> 4ba56f3d5a65..f70bd7d28ff8 100644
>> --- a/drivers/cxl/core/mbox.c
>> +++ b/drivers/cxl/core/mbox.c
>> @@ -968,6 +968,47 @@ int cxl_get_supported_feature_entry(struct
>> cxl_dev_state *cxlds, const uuid_t *f  }
>> EXPORT_SYMBOL_NS_GPL(cxl_get_supported_feature_entry, CXL);
>>
>> +size_t cxl_get_feature(struct cxl_dev_state *cxlds, const uuid_t feat_uuid,
>> +		       enum cxl_get_feat_selection selection,
>> +		       void *feat_out, size_t feat_out_size) {
>> +	struct cxl_mailbox *cxl_mbox = &cxlds->cxl_mbox;
>
>cxlds is otherwise unused in this function, just pass in @cxl_mbox directly.

Hi Dan,

I  modified to cxl_get_feature(struct cxl_mailbox *cxl_mbox, ..) in the EDAC CXL features setup and tested fine.

Thanks,
Shiju