bootstage: Add a number of new features

It is useful to be able to communicate the bootstage information to another program, such as the kernel, either by putting it in memory or the device tree. This makes the information accessible after boot so that it can easily be logged somewhere or perhaps reported back for diagnostics purposes. This series includes a few patches to implement this.

Sometimes a peripheral is touched multiple times during boot, or a single task is called repeatedly. Examples are reading from a device, which might happen in several parts, or setting up an LCD display, which may involve multiple steps to comply with backlight power sequences. This series adds a new bootstage time accumulation feature to add up all the time spent in a particular task.

This series also adds a new command 'bootstage' to provide access to the above features.

Simon Glass (6):
bootstage: Export bootstage_add_record() function
bootstage: Add time accumulation feature
bootstage: Store boot timings in device tree
bootstage: Add feature to stash/unstash bootstage info
bootstage: Add bootstage command
bootstage: Add new bootstage IDs for board, LCD

 README                 |   25 ++++
 arch/arm/lib/bootm.c   |    3 +
 common/Makefile        |    1 +
 common/bootstage.c     |  306 +++++++++++++++++++++++++++++++++++++++++++++---
 common/cmd_bootstage.c |  116 ++++++++++++++++++
 include/bootstage.h    |   85 +++++++++++++
 6 files changed, 517 insertions(+), 19 deletions(-)
 create mode 100644 common/cmd_bootstage.c