RE: [RFC PATCH v9 06/11] cxl/mbox: Add SET_FEATURE mailbox command

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

>-----Original Message-----
>From: nifan.cxl@gmail.com <nifan.cxl@gmail.com>
>Sent: 17 July 2024 21:14
>To: Shiju Jose <shiju.jose@huawei.com>
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>Subject: Re: [RFC PATCH v9 06/11] cxl/mbox: Add SET_FEATURE mailbox
>command
>
>On Tue, Jul 16, 2024 at 04:03:30PM +0100, shiju.jose@huawei.com wrote:
>> From: Shiju Jose <shiju.jose@huawei.com>
>>
>> Add support for SET_FEATURE mailbox command.
>>
>> CXL spec 3.1 section 8.2.9.6 describes optional device specific features.
>> CXL devices supports features with changeable attributes.
>> The settings of a feature can be optionally modified using Set Feature
>> command.
>
>Add more specific spec reference to the command here: 8.2.9.6.3.
>The same suggestions for get supported features and get feature commands.
Will do.

>
>>
>> Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
>> ---
>>  drivers/cxl/core/mbox.c | 71
>+++++++++++++++++++++++++++++++++++++++++
>>  drivers/cxl/cxlmem.h    | 33 +++++++++++++++++++
>>  2 files changed, 104 insertions(+)
>>
>> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c index
>> b1eeed508459..50ecd2bd7372 100644
>> --- a/drivers/cxl/core/mbox.c
>> +++ b/drivers/cxl/core/mbox.c
>> @@ -1388,6 +1388,77 @@ size_t cxl_get_feature(struct cxl_memdev_state
>> *mds,  }  EXPORT_SYMBOL_NS_GPL(cxl_get_feature, CXL);
>>
>> +/*
>> + * FEAT_DATA_MIN_PAYLOAD_SIZE - min extra number of bytes should be
>> + * available in the mailbox for storing the actual feature data so
>> +that
>> + * the feature data transfer would work as expected.
>> + */
>> +#define FEAT_DATA_MIN_PAYLOAD_SIZE 10 int cxl_set_feature(struct
>> +cxl_memdev_state *mds,
>> +		    const uuid_t feat_uuid, u8 feat_version,
>> +		    void *feat_data, size_t feat_data_size,
>> +		    u8 feat_flag)
>> +{
>> +	struct cxl_memdev_set_feat_pi {
>> +		struct cxl_mbox_set_feat_hdr hdr;
>> +		u8 feat_data[];
>> +	}  __packed;
>> +	size_t data_in_size, data_sent_size = 0;
>> +	struct cxl_mbox_cmd mbox_cmd;
>> +	size_t hdr_size;
>> +	int rc = 0;
>> +
>> +	struct cxl_memdev_set_feat_pi *pi __free(kfree) =
>> +					kmalloc(mds->payload_size,
>GFP_KERNEL);
>> +	pi->hdr.uuid = feat_uuid;
>> +	pi->hdr.version = feat_version;
>> +	feat_flag &= ~CXL_SET_FEAT_FLAG_DATA_TRANSFER_MASK;
>
>Although we may not support it yet, should we set bit[3] (saved across reset)
>since we already defined CXL_SET_FEAT_FLAG_DATA_SAVED_ACROSS_RESET
>and it is not used?
Will do.
>
>Fan
>> +	hdr_size = sizeof(pi->hdr);
>> +	/*
>> +	 * Check minimum mbox payload size is available for
>> +	 * the feature data transfer.
>> +	 */
>> +	if (hdr_size + FEAT_DATA_MIN_PAYLOAD_SIZE > mds->payload_size)
>> +		return -ENOMEM;
>> +
>> +	if ((hdr_size + feat_data_size) <= mds->payload_size) {
>> +		pi->hdr.flags = cpu_to_le32(feat_flag |
>> +
>CXL_SET_FEAT_FLAG_FULL_DATA_TRANSFER);
>> +		data_in_size = feat_data_size;
>> +	} else {
>> +		pi->hdr.flags = cpu_to_le32(feat_flag |
>> +
>CXL_SET_FEAT_FLAG_INITIATE_DATA_TRANSFER);
>> +		data_in_size = mds->payload_size - hdr_size;
>> +	}
>> +
>> +	do {
>> +		pi->hdr.offset = cpu_to_le16(data_sent_size);
>> +		memcpy(pi->feat_data, feat_data + data_sent_size,
>data_in_size);
>> +		mbox_cmd = (struct cxl_mbox_cmd) {
>> +			.opcode = CXL_MBOX_OP_SET_FEATURE,
>> +			.size_in = hdr_size + data_in_size,
>> +			.payload_in = pi,
>> +		};
>> +		rc = cxl_internal_send_cmd(mds, &mbox_cmd);
>> +		if (rc < 0)
>> +			return rc;
>> +
>> +		data_sent_size += data_in_size;
>> +		if (data_sent_size >= feat_data_size)
>> +			return 0;
>> +
>> +		if ((feat_data_size - data_sent_size) <= (mds->payload_size -
>hdr_size)) {
>> +			data_in_size = feat_data_size - data_sent_size;
>> +			pi->hdr.flags = cpu_to_le32(feat_flag |
>> +
>CXL_SET_FEAT_FLAG_FINISH_DATA_TRANSFER);
>> +		} else {
>> +			pi->hdr.flags = cpu_to_le32(feat_flag |
>> +
>CXL_SET_FEAT_FLAG_CONTINUE_DATA_TRANSFER);
>> +		}
>> +	} while (true);
>> +}
>> +EXPORT_SYMBOL_NS_GPL(cxl_set_feature, CXL);
>> +
>>  int cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len,
>>  		       struct cxl_region *cxlr)
>>  {
>> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h index
>> 25698a6fbe66..c3cb8e2736b5 100644
>> --- a/drivers/cxl/cxlmem.h
>> +++ b/drivers/cxl/cxlmem.h
>> @@ -532,6 +532,7 @@ enum cxl_opcode {
>>  	CXL_MBOX_OP_GET_SUP_LOG_SUBLIST = 0x0405,
>>  	CXL_MBOX_OP_GET_SUPPORTED_FEATURES	= 0x0500,
>>  	CXL_MBOX_OP_GET_FEATURE		= 0x0501,
>> +	CXL_MBOX_OP_SET_FEATURE		= 0x0502,
>>  	CXL_MBOX_OP_IDENTIFY		= 0x4000,
>>  	CXL_MBOX_OP_GET_PARTITION_INFO	= 0x4100,
>>  	CXL_MBOX_OP_SET_PARTITION_INFO	= 0x4101,
>> @@ -780,6 +781,34 @@ struct cxl_mbox_get_feat_in {
>>  	u8 selection;
>>  }  __packed;
>>
>> +/*
>> + * Set Feature CXL 3.1 Spec 8.2.9.6.3  */
>> +
>> +/*
>> + * Set Feature input payload
>> + * CXL rev 3.1 section 8.2.9.6.3 Table 8-101  */
>> +/* Set Feature : Payload in flags */
>> +#define CXL_SET_FEAT_FLAG_DATA_TRANSFER_MASK	GENMASK(2, 0)
>> +enum cxl_set_feat_flag_data_transfer {
>> +	CXL_SET_FEAT_FLAG_FULL_DATA_TRANSFER,
>> +	CXL_SET_FEAT_FLAG_INITIATE_DATA_TRANSFER,
>> +	CXL_SET_FEAT_FLAG_CONTINUE_DATA_TRANSFER,
>> +	CXL_SET_FEAT_FLAG_FINISH_DATA_TRANSFER,
>> +	CXL_SET_FEAT_FLAG_ABORT_DATA_TRANSFER,
>> +	CXL_SET_FEAT_FLAG_DATA_TRANSFER_MAX
>> +};
>> +#define CXL_SET_FEAT_FLAG_DATA_SAVED_ACROSS_RESET	BIT(3)
>> +
>> +struct cxl_mbox_set_feat_hdr {
>> +	uuid_t uuid;
>> +	__le32 flags;
>> +	__le16 offset;
>> +	u8 version;
>> +	u8 rsvd[9];
>> +}  __packed;
>> +
>>  /* Get Poison List  CXL 3.0 Spec 8.2.9.8.4.1 */  struct
>> cxl_mbox_poison_in {
>>  	__le64 offset;
>> @@ -918,6 +947,10 @@ size_t cxl_get_feature(struct cxl_memdev_state
>*mds,
>>  		       const uuid_t feat_uuid, void *feat_out,
>>  		       size_t feat_out_size,
>>  		       enum cxl_get_feat_selection selection);
>> +int cxl_set_feature(struct cxl_memdev_state *mds,
>> +		    const uuid_t feat_uuid, u8 feat_version,
>> +		    void *feat_data, size_t feat_data_size,
>> +		    u8 feat_flag);
>>  int cxl_poison_state_init(struct cxl_memdev_state *mds);  int
>> cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len,
>>  		       struct cxl_region *cxlr);
>> --
>> 2.34.1
>>

Thanks,
Shiju