This also involves adding a quirk table as TRIM is broken for some
Kingston eMMC devices, though. Compared to ERASE (declared "legacy"
in the eMMC specification v5.1), TRIM has the advantage of operating
on write sectors rather than on erase sectors, which typically are
of a much larger size. Thus, employing TRIM, we don't need to fiddle
with coalescing BIO_DELETE requests that are also of (write) sector
units into erase sectors, which might not even add up in all cases.
- For some SanDisk iNAND devices, the CMD38 argument, e. g. ERASE,
TRIM etc., has to be specified via EXT_CSD[113], which now is also
handled via a quirk.
- My initial understanding was that for eMMC partitions, the granularity
should be used as erase sector size, e. g. 128 KB for boot partitions.
However, rereading the relevant parts of the eMMC specification v5.1,
this isn't actually correct. So drop the code which used partition
granularities for delmaxsize and stripesize. For the most part, this
change is a NOP, though, because a) for ERASE, mmcsd_delete() used
the erase sector size unconditionally for all partitions anyway and
b) g_disk_limit() doesn't actually take the stripesize into account.
- Take some more advantage of mmcsd_errmsg() in mmcsd(4) for making
error codes human readable.
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