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cxl/mbox: Add SET_FEATURE mailbox command
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Add support for SET_FEATURE mailbox command.

CXL spec r3.2 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.
CXL spec r3.2 section 8.2.9.6.3 describes Set Feature command.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Li Ming <ming.li@zohomail.com>
Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
Link: https://patch.msgid.link/20250220194438.2281088-6-dave.jiang@intel.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
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Shiju Jose authored and Dave Jiang committed Feb 26, 2025
1 parent 5e5ac21 commit 14d502c
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4 changes: 4 additions & 0 deletions drivers/cxl/core/core.h
Original file line number Diff line number Diff line change
Expand Up @@ -122,6 +122,10 @@ size_t cxl_get_feature(struct cxl_mailbox *cxl_mbox, const uuid_t *feat_uuid,
enum cxl_get_feat_selection selection,
void *feat_out, size_t feat_out_size, u16 offset,
u16 *return_code);
int cxl_set_feature(struct cxl_mailbox *cxl_mbox, const uuid_t *feat_uuid,
u8 feat_version, const void *feat_data,
size_t feat_data_size, u32 feat_flag, u16 offset,
u16 *return_code);
#endif

#endif /* __CXL_CORE_H__ */
80 changes: 80 additions & 0 deletions drivers/cxl/core/features.c
Original file line number Diff line number Diff line change
Expand Up @@ -223,3 +223,83 @@ size_t cxl_get_feature(struct cxl_mailbox *cxl_mbox, const uuid_t *feat_uuid,

return data_rcvd_size;
}

/*
* 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_mailbox *cxl_mbox,
const uuid_t *feat_uuid, u8 feat_version,
const void *feat_data, size_t feat_data_size,
u32 feat_flag, u16 offset, u16 *return_code)
{
size_t data_in_size, data_sent_size = 0;
struct cxl_mbox_cmd mbox_cmd;
size_t hdr_size;

if (return_code)
*return_code = CXL_MBOX_CMD_RC_INPUT;

struct cxl_mbox_set_feat_in *pi __free(kfree) =
kzalloc(cxl_mbox->payload_size, GFP_KERNEL);
if (!pi)
return -ENOMEM;

uuid_copy(&pi->uuid, feat_uuid);
pi->version = feat_version;
feat_flag &= ~CXL_SET_FEAT_FLAG_DATA_TRANSFER_MASK;
feat_flag |= CXL_SET_FEAT_FLAG_DATA_SAVED_ACROSS_RESET;
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 > cxl_mbox->payload_size)
return -ENOMEM;

if (hdr_size + feat_data_size <= cxl_mbox->payload_size) {
pi->flags = cpu_to_le32(feat_flag |
CXL_SET_FEAT_FLAG_FULL_DATA_TRANSFER);
data_in_size = feat_data_size;
} else {
pi->flags = cpu_to_le32(feat_flag |
CXL_SET_FEAT_FLAG_INITIATE_DATA_TRANSFER);
data_in_size = cxl_mbox->payload_size - hdr_size;
}

do {
int rc;

pi->offset = cpu_to_le16(offset + 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(cxl_mbox, &mbox_cmd);
if (rc < 0) {
if (return_code)
*return_code = mbox_cmd.return_code;
return rc;
}

data_sent_size += data_in_size;
if (data_sent_size >= feat_data_size) {
if (return_code)
*return_code = CXL_MBOX_CMD_RC_SUCCESS;
return 0;
}

if ((feat_data_size - data_sent_size) <= (cxl_mbox->payload_size - hdr_size)) {
data_in_size = feat_data_size - data_sent_size;
pi->flags = cpu_to_le32(feat_flag |
CXL_SET_FEAT_FLAG_FINISH_DATA_TRANSFER);
} else {
pi->flags = cpu_to_le32(feat_flag |
CXL_SET_FEAT_FLAG_CONTINUE_DATA_TRANSFER);
}
} while (true);
}
33 changes: 33 additions & 0 deletions include/cxl/features.h
Original file line number Diff line number Diff line change
Expand Up @@ -90,6 +90,39 @@ enum cxl_get_feat_selection {
CXL_GET_FEAT_SEL_MAX
};

/*
* Set Feature CXL spec r3.2 8.2.9.6.3
*/

/*
* Set Feature input payload
* CXL spec r3.2 section 8.2.9.6.3 Table 8-101
*/
struct cxl_mbox_set_feat_in {
__struct_group(cxl_mbox_set_feat_hdr, hdr, /* no attrs */,
uuid_t uuid;
__le32 flags;
__le16 offset;
u8 version;
u8 rsvd[9];
);
__u8 feat_data[];
} __packed;

/* Set Feature flags field */
enum cxl_set_feat_flag_data_transfer {
CXL_SET_FEAT_FLAG_FULL_DATA_TRANSFER = 0,
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_TRANSFER_MASK GENMASK(2, 0)

#define CXL_SET_FEAT_FLAG_DATA_SAVED_ACROSS_RESET BIT(3)

/**
* struct cxl_features_state - The Features state for the device
* @cxlds: Pointer to CXL device state
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