hw/cxl: Support firmware updates

hw/cxl: Support firmware updates

Implement transfer and activate functionality per 3.1 spec for
supporting update metadata (no actual buffers). Transfer times
are arbitrarily set to ten and two seconds for full and part
transfers, respectively.

cxl update-firmware mem0 -F fw.img

<on-going fw update>

cxl update-firmware mem0
  "memdev":"mem0",
  "pmem_size":"1024.00 MiB (1073.74 MB)",
  "serial":"0",
  "host":"0000:0d:00.0",
  "firmware":{
    "num_slots":2,
    "active_slot":1,
    "online_activate_capable":true,
    "slot_1_version":"BWFW VERSION 0",
    "fw_update_in_progress":true,
    "remaining_size":22400
  }
}

<completed fw update>

cxl update-firmware mem0
{
  "memdev":"mem0",
  "pmem_size":"1024.00 MiB (1073.74 MB)",
  "serial":"0",
  "host":"0000:0d:00.0",
  "firmware":{
    "num_slots":2,
    "active_slot":1,
    "staged_slot":2,
    "online_activate_capable":true,
    "slot_1_version":"BWFW VERSION 0",
    "slot_2_version":"BWFW VERSION 1",
    "fw_update_in_progress":false
  }
}

Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Link: https://lore.kernel.org/r/20240627164912.25630-1-dave@stgolabs.net
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20240705125915.991672-2-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>