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Diffstat (limited to 'board/edb93xx/early_udelay.h')
-rw-r--r-- | board/edb93xx/early_udelay.h | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/board/edb93xx/early_udelay.h b/board/edb93xx/early_udelay.h new file mode 100644 index 0000000..3b26b3f --- /dev/null +++ b/board/edb93xx/early_udelay.h @@ -0,0 +1,34 @@ +/* + * Copyright (C) 2009 Matthias Kaehlcke <matthias@kaehlcke.net> + * + * See file CREDITS for list of people who contributed to this + * project. + * + * 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; either version 2 of + * the License, or (at your option) any later version. + * + * 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., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#include <common.h> + +/* delay execution before timers are initialized */ +static inline void early_udelay(uint32_t usecs) +{ + /* loop takes 4 cycles at 5.0ns (fastest case, running at 200MHz) */ + register uint32_t loops = (usecs * 1000) / 20; + + __asm__ volatile ("1:\n" + "subs %0, %1, #1\n" + "bne 1b":"=r" (loops):"0" (loops)); +} |