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→Embedded Linux systems with eMMC or SD cards
Regardless of the file system used, e.MMC devices provide some functionalities conceived to monitor their health while operating. As these functionalities are defined by [https://www.jedec.org/sites/default/files/docs/JESD84-B51.pdf JEDEC standards], all the vendors implement them.
In practice, e.MMC's integrates integrate some registers providing specific information about the health status. These registers can be accessed with the <code>mmc-utils</code>, which are documented [https://www.kernel.org/doc/html/latest/driver-api/mmc/mmc-tools.html here]. Interestingly, JEDEC standard also defines a set of registers (<code>VENDOR_PROPRIETARY_HEALTH_REPORT</code>) that vendors are free to use for providing further, fine-grained information about the device's health status. Engineers and system integrators are supposed to contact the e.MMC manufacturer to get the required tools for accessing such registers.
The sections related to eMMC-based use cases are the result of a joint effort between [https://www.westerndigital.com/ Western Digital] (which purchased [https://en.wikipedia.org/wiki/SanDisk SanDisk] in 2016), Lauterbach Italy, and DAVE Embedded Systems. Parts of such sections are retrieved from the White Paper ''TRACE32 log method for analysing accesses to an eMMC device'' by Lauterbach, which is freely available for download [https://www.lauterbach.com/publications/trace32_log_method_for_analysing_accesses_to_an_emmc_device.pdf here].
Following is a dump of the standard registers of the targte's e.MMC related to the wear-out status of the device, namely <code>DEVICE_LIFE_TIME_EST_TYP_B</code>, <code>DEVICE_LIFE_TIME_EST_TYP_B</code>, and <code>PRE_EOL_INFO</code>.
root@desk-mx8mp:~# mmc extcsd read /dev/mmcblk2 | grep LIFE
eMMC Life Time Estimation A [EXT_CSD_DEVICE_LIFE_TIME_EST_TYP_A]: 0x01
eMMC Life Time Estimation B [EXT_CSD_DEVICE_LIFE_TIME_EST_TYP_B]: 0x01
root@desk-mx8mp:~# mmc extcsd read /dev/mmcblk2 | grep EOL
eMMC Pre EOL information [EXT_CSD[ 2541.032394] mmcblk2:
_PRE_EOL_INFO]: 0x01
TBD
