Rework the timeout code to use actual time rather than a DELAY() loop and
to use both typical and maximum to allow logging of timeout failures.
Also correct the erase timeout, it is specified in milliseconds not
microseconds like the other timeouts. Do not invoke DELAY() between
status queries as this adds significant latency which in turn reduced
write performance substantially.
Sanity check timeout values from the hardware.
Implement support for buffered writes (only enabled on Intel/Sharp parts
for now). This yields an order of magnitude speedup on the 64MB Intel
StrataFlash parts we use.
When making a copy of the block to modify, also keep a clean copy around
until we are ready to commit the block and use it to avoid unnecessary
erases. In the non-buffer write case, also use it to avoid
unnecessary writes when the block has not been erased. This yields a
significant speedup when doing things like zeroing a block.
Sponsored by: DARPA, AFRL
Reviewed by: imp (previous version)
d_getattr(). Since these drivers use disk(9) KPI and not directly GEOM, use
of that function means KPI layering violation, causing extra g_io_deliver()
call for the request.
The flash commands and responses are little-endian and have to be
byte swapped on big-endian systems. However the raw read of data
need not be swapped.
Make the cfi_read and cfi_write do the swapping, and provide a
cfi_read_raw which does not byte swap for reading data from
flash.
this fixes geom_redboot on boards that have multiple parts/regions as it
uses the value to locate the FIS directory which is in the last erase
region of flash
