docs/designs/nvmemi-over-smbus.md

1 ### NVMe-MI over SMBus
9 Currently, OpenBMC does not support NVMe drive information. NVMe-MI
10 specification defines a command that can read the NVMe drive information via
11 SMBus directly. The NVMe drive can provide its information or status, like
13 monitor NVMe drives so appropriate action can be taken.
17 NVMe-MI specification defines a command called
18 `NVM Express Basic Management Command` that can read the NVMe drives information
22 For our purpose is retrieve NVMe drives information, therefore, using NVM
23 Express Basic Management Command where describe in NVMe-MI specification to
24 communicate with NVMe drives. According to different platforms, temperature
36 - Provide a daemon to monitor NVMe drives. Parameters to be monitored are Status
40 - Capability of communication over hardware channel I2C to NVMe drives.
47 each NVMe sensor: "/xyz/openbmc_project/sensors/temperature/nvme0",
160    3. Send a NVMe-MI command via SMBus Block Read protocol by bus ID of target
161       drive to get data. Data get from NVMe drives are "Status Flags", "SMART
166 This service will run automatically and look up NVMe drives every second.
173 ##### Add SEL related to NVMe
176 `DegradesFault` and `MediaFault` will be generated for the NVMe errors.
186 NVMe-MI specification defines multiple commands that can communicate with NVMe
187 drives over MCTP protocol. The NVMe-MI over MCTP has the following key
196 For monitoring NVMe drives, using NVM Express Basic Management Command over
197 SMBus directly is much simpler than NVMe-MI over MCTP protocol.
201 This application is monitoring NVMe drives via SMbus and set values to D-bus.
206 This implementation is to use NVMe-MI-Basic command over SMBus and then set the
209 same. The testing can be performed on different NVMe drives by different
215   getting NVMe information.