From e5e36306a9a5bf96ab8cc990d93bbd62030e635f Mon Sep 17 00:00:00 2001 From: Aaron Durbin Date: Thu, 25 Sep 2014 10:05:15 -0500 Subject: timer: Add generic udelay() implementation Add GENERIC_UDELAY Kconfig option so that a generic udelay() implementation is provided utilizing the monotonic timer. That way each board/chipset doesn't need to duplicate the same udelay(). Additionally, assume that GENERIC_UDELAY implies init_timer() is not required. BUG=None BRANCH=None TEST=Built nyan, ryu, and rambi. May need help testing. Change-Id: I7f511a2324b5aa5d1b2959f4519be85a6a7360e8 Signed-off-by: Patrick Georgi Original-Commit-Id: 1a85fbcad778933d13eaef545135abe7e4de46ed Original-Change-Id: Idd26de19eefc91ee3b0ceddfb1bc2152e19fd8ab Original-Signed-off-by: Aaron Durbin Original-Reviewed-on: https://chromium-review.googlesource.com/219719 Original-Reviewed-by: Julius Werner Original-Reviewed-by: Furquan Shaikh Reviewed-on: http://review.coreboot.org/9334 Tested-by: build bot (Jenkins) Reviewed-by: Patrick Georgi --- src/lib/timer.c | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 src/lib/timer.c (limited to 'src/lib/timer.c') diff --git a/src/lib/timer.c b/src/lib/timer.c new file mode 100644 index 0000000000..a2edc5c96d --- /dev/null +++ b/src/lib/timer.c @@ -0,0 +1,42 @@ +/* + * This file is part of the coreboot project. + * + * Copyright 2014 Google Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include +#include +#include +#include + +void udelay(unsigned usec) +{ + struct stopwatch sw; + + /* + * As the timer granularity is in microseconds pad the + * requested delay by one to get at least >= requested usec delay. + */ + usec += 1; + + if (!thread_yield_microseconds(usec)) + return; + + stopwatch_init_usecs_expire(&sw, usec); + + while (!stopwatch_expired(&sw)) + ; +} -- cgit v1.2.3