Is it possible to know the wear level information of a phone, like SSD have with SMART?

SMART was originally designed for ATA devices and extended to SCSI and PCIe/NVMe later to cover almost the whole range of HDDs/SSDs. Trying to send SMART commands to eMMC, e.g. using smartctl would throw error: Unable to detect device type. Please specify device type with the -d option.

Unlike SATA or SAS, eMMC communicates over parallel links and has a different command set. One of these commands (CMD8) dumps the Extended CSD (Card Specific Data) register which holds card's internal information and device capabilities including Life Time Estimation and Pre EOL (End of Life) Estimation. EXT_CSD register can be read (requires root) using mmc tool from mmc-utils:

~# mmc extcsd read /dev/block/mmcblk0 | grep -E 'LIFE|EOL'

eMMC Life Time Estimation A [EXT_CSD_DEVICE_LIFE_TIME_EST_TYP_A]: 0x03

eMMC Life Time Estimation B [EXT_CSD_DEVICE_LIFE_TIME_EST_TYP_B]: 0x03

eMMC Pre EOL information [EXT_CSD_PRE_EOL_INFO]: 0x01

<sup>* 0x03 indicates health status is estimated between 20% and 30% of the device lifespan.

* 0x01 indicates Normal pre-EOL status.</sup>

Depending on your MMC driver, the above information is also available through sysfs interfaces:

~# cat /sys/devices/soc/7824900.sdhci/mmc_host/mmc0/mmc0:0001/{
life_time,pre_eol_info
}


0x03 0x03

01

^{* Path may differ depending on eMMC vendor.}

Another option is to read ECSD register from debugfs:

~# cat /sys/kernel/debug/mmc0/mmc0:0001/ext_csd

But parsing ECSD raw output is an extra job.

For UFS part I'm not sure at the moment if the health/wear estimation is available through HCI Capabilities Registers or not. Also unlike eMMC, UFS operates over a serial communication link and supports a subset of SCSI commands. So it might be providing SMART (or SMART-like) monitoring system. Someone else may update the answer if some authentic source of information is available.

REFERENCES:

• Wear Estimation for Devices with eMMC Flash Memory


• eMMC ELECTRICAL STANDARD (5.1) (JESD84-B51A)


• UFS in Linux kernel


• UFS Overview