Re: [PATCH v14 05/14] cxl/mbox: Add GET_FEATURE mailbox command

[Dave Jiang <dave.jiang@intel.com>]

On 10/25/24 10:13 AM, shiju.jose@huawei.com 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.
> 
> Reviewed-by: Fan Ni <fan.ni@samsung.com>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Signed-off-by: Shiju Jose <shiju.jose@huawei.com>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>
> ---
>  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 5045960e3bfe..3cd4bce2872d 100644
> --- a/drivers/cxl/core/mbox.c
> +++ b/drivers/cxl/core/mbox.c
> @@ -970,6 +970,47 @@ int cxl_get_supported_feature_entry(struct cxl_memdev_state *mds, const uuid_t *
>  }
>  EXPORT_SYMBOL_NS_GPL(cxl_get_supported_feature_entry, CXL);
>  
> +size_t cxl_get_feature(struct cxl_memdev_state *mds, const uuid_t feat_uuid,
> +		       enum cxl_get_feat_selection selection,
> +		       void *feat_out, size_t feat_out_size)
> +{
> +	struct cxl_mailbox *cxl_mbox = &mds->cxlds.cxl_mbox;
> +	size_t data_to_rd_size, size_out;
> +	struct cxl_mbox_get_feat_in pi;
> +	struct cxl_mbox_cmd mbox_cmd;
> +	size_t data_rcvd_size = 0;
> +	int rc;
> +
> +	if (!feat_out || !feat_out_size)
> +		return 0;
> +
> +	size_out = min(feat_out_size, cxl_mbox->payload_size);
> +	pi.uuid = feat_uuid;
> +	pi.selection = selection;
> +	do {
> +		data_to_rd_size = min(feat_out_size - data_rcvd_size,
> +				      cxl_mbox->payload_size);
> +		pi.offset = cpu_to_le16(data_rcvd_size);
> +		pi.count = cpu_to_le16(data_to_rd_size);
> +
> +		mbox_cmd = (struct cxl_mbox_cmd) {
> +			.opcode = CXL_MBOX_OP_GET_FEATURE,
> +			.size_in = sizeof(pi),
> +			.payload_in = &pi,
> +			.size_out = size_out,
> +			.payload_out = feat_out + data_rcvd_size,
> +			.min_out = data_to_rd_size,
> +		};
> +		rc = cxl_internal_send_cmd(cxl_mbox, &mbox_cmd);
> +		if (rc < 0 || !mbox_cmd.size_out)
> +			return 0;
> +		data_rcvd_size += mbox_cmd.size_out;
> +	} while (data_rcvd_size < feat_out_size);
> +
> +	return data_rcvd_size;
> +}
> +EXPORT_SYMBOL_NS_GPL(cxl_get_feature, CXL);
> +
>  /**
>   * cxl_enumerate_cmds() - Enumerate commands for a device.
>   * @mds: The driver data for the operation
> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
> index f88b10188632..0c152719669a 100644
> --- a/drivers/cxl/cxlmem.h
> +++ b/drivers/cxl/cxlmem.h
> @@ -531,6 +531,7 @@ enum cxl_opcode {
>  	CXL_MBOX_OP_CLEAR_LOG           = 0x0403,
>  	CXL_MBOX_OP_GET_SUP_LOG_SUBLIST = 0x0405,
>  	CXL_MBOX_OP_GET_SUPPORTED_FEATURES	= 0x0500,
> +	CXL_MBOX_OP_GET_FEATURE		= 0x0501,
>  	CXL_MBOX_OP_IDENTIFY		= 0x4000,
>  	CXL_MBOX_OP_GET_PARTITION_INFO	= 0x4100,
>  	CXL_MBOX_OP_SET_PARTITION_INFO	= 0x4101,
> @@ -856,6 +857,28 @@ struct cxl_mbox_get_sup_feats_out {
>  	struct cxl_feat_entry ents[] __counted_by_le(supported_feats);
>  } __packed;
>  
> +/*
> + * Get Feature CXL 3.1 Spec 8.2.9.6.2
> + */
> +
> +/*
> + * Get Feature input payload
> + * CXL rev 3.1 section 8.2.9.6.2 Table 8-99
> + */
> +enum cxl_get_feat_selection {
> +	CXL_GET_FEAT_SEL_CURRENT_VALUE,
> +	CXL_GET_FEAT_SEL_DEFAULT_VALUE,
> +	CXL_GET_FEAT_SEL_SAVED_VALUE,
> +	CXL_GET_FEAT_SEL_MAX
> +};
> +
> +struct cxl_mbox_get_feat_in {
> +	uuid_t uuid;
> +	__le16 offset;
> +	__le16 count;
> +	u8 selection;
> +}  __packed;
> +
>  int cxl_internal_send_cmd(struct cxl_mailbox *cxl_mbox,
>  			  struct cxl_mbox_cmd *cmd);
>  int cxl_dev_state_identify(struct cxl_memdev_state *mds);
> @@ -919,4 +942,7 @@ void cxl_dpa_debug(struct seq_file *file, struct cxl_dev_state *cxlds);
>  int cxl_get_supported_features(struct cxl_memdev_state *mds);
>  int cxl_get_supported_feature_entry(struct cxl_memdev_state *mds, const uuid_t *feat_uuid,
>  				    struct cxl_feat_entry *feat_entry_out);
> +size_t cxl_get_feature(struct cxl_memdev_state *mds, const uuid_t feat_uuid,
> +		       enum cxl_get_feat_selection selection,
> +		       void *feat_out, size_t feat_out_size);
>  #endif /* __CXL_MEM_H__ */