bootstage: Implement core microsecond boot time measurement
This defines the basics of a new boot time measurement feature. This allows
logging of very accurate time measurements as the boot proceeds, by using
an available microsecond counter.
To enable the feature, define CONFIG_BOOTSTAGE in your board config file.
Also available is CONFIG_BOOTSTAGE_REPORT which will cause a report to be
printed just before handing off to the OS.
Most IDs are not named at this stage. For that I would first like to
renumber them all.
Timer summary in microseconds:
Mark Elapsed Stage
0 0 reset
205,000 205,000 board_init_f
6,053,000 5,848,000 bootm_start
6,053,000 0 id=1
6,058,000 5,000 id=101
6,058,000 0 id=100
6,061,000 3,000 id=103
6,064,000 3,000 id=104
6,093,000 29,000 id=107
6,093,000 0 id=106
6,093,000 0 id=105
6,093,000 0 id=108
7,089,000 996,000 id=7
7,089,000 0 id=15
7,089,000 0 id=8
7,097,000 8,000 start_kernel
Signed-off-by: Simon Glass <sjg@chromium.org>