uboot/arch/arm/include/asm/arch-armv7/generictimer.h
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   1/*
   2 * Copyright (C) 2013 - ARM Ltd
   3 * Author: Marc Zyngier <marc.zyngier@arm.com>
   4 *
   5 * Based on code by Carl van Schaik <carl@ok-labs.com>.
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License version 2 as
   9 * published by the Free Software Foundation.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20#ifndef _GENERICTIMER_H_
  21#define _GENERICTIMER_H_
  22
  23#ifdef __ASSEMBLY__
  24
  25/*
  26 * This macro provide a physical timer that can be used for delay in the code.
  27 * The macro is moved from sunxi/psci_sun7i.S
  28 *
  29 * reg: is used in this macro.
  30 * ticks: The freq is based on generic timer.
  31 */
  32.macro  timer_wait      reg, ticks
  33        movw    \reg, #(\ticks & 0xffff)
  34        movt    \reg, #(\ticks >> 16)
  35        mcr     p15, 0, \reg, c14, c2, 0
  36        isb
  37        mov     \reg, #3
  38        mcr     p15, 0, \reg, c14, c2, 1
  391 :     isb
  40        mrc     p15, 0, \reg, c14, c2, 1
  41        ands    \reg, \reg, #4
  42        bne     1b
  43        mov     \reg, #0
  44        mcr     p15, 0, \reg, c14, c2, 1
  45        isb
  46.endm
  47
  48#endif /* __ASSEMBLY__ */
  49
  50#endif /* _GENERICTIMER_H_ */
  51