Add 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.

BUG=chromium-os:13875
TEST=build and boot, check that progress is reported before running Linux:

Timer summary in microseconds:
       Mark    Elapsed  Stage
          0          0  awake
  2,181,078  2,181,078  usb_start
 11,861,817  9,680,739  bootp_start
 11,884,610     22,793  bootp_stop
 11,884,689         79  tftp start
 15,271,536  3,386,847  tftp done
 15,271,568         32  bootm_start
 15,406,551    134,983  start_kernel

Change-Id: I71b89c8402dc5dec75e68333bd24a6bab7500a1b
Reviewed-on: http://gerrit.chromium.org/gerrit/197
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/net/net.c b/net/net.c
index 7a6058339c..272fb5bad7 100644
--- a/net/net.c
+++ b/net/net.c
@@ -378,6 +378,7 @@ NetLoop(proto_t protocol)
 		NetArpWaitTxPacketSize = 0;
 	}
 
+	bootstage_mark(BOOTSTAGE_ETH_START, "eth_start");
 	eth_halt();
 #ifdef CONFIG_NET_MULTI
 	eth_set_current();