u-boot/board/edb93xx/early_udelay.h
Alessandro Rubini 822bd70db4 edb93xx: change calculation un early_udelay.h
Previous code compiled with gcc-4.2.2 makes a call to
__aeabi_uidiv to divide by 20. As a side effect it was
not inline any more, and so sdram_cfg used the stack
as well, but this is early code that has no stack yet.
The patch explicitly removes the division, so no stack is used.

The calculation of the counter calls a division by 20

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
2010-02-12 12:31:54 -06:00

34 lines
1.2 KiB
C

/*
* 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));
}