This enables to capture snapshot of controller information via device
coredump machanism.
The nvme device coredump creates the following coredump files.
- regs: NVMe controller registers (00h to 4Fh)
- sq<qid>: Submission queue
- cq<qid>: Completion queue
- telemetry-ctrl-log: Telemetry controller-initiated log (if available)
- data: Empty
The reason for an empty 'data' file is to provide a uniform way to notify
the device coredump is no longer needed by writing the 'data' file.
Since all existing drivers using the device coredump provide a 'data' file
if the nvme device coredump doesn't provide it, the userspace programs need
to know which driver provides what coredump file.
Cc: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
Cc: Keith Busch <keith.busch@xxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Sagi Grimberg <sagi@xxxxxxxxxxx>
Cc: Minwoo Im <minwoo.im.dev@xxxxxxxxx>
Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>