target/linux/ubicom32/files/arch/ubicom32/include/asm/delay.h

   1 /*
   2  * arch/ubicom32/include/asm/delay.h
   3  *   Definition of delay routines for Ubicom32 architecture.
   4  *
   5  * (C) Copyright 2009, Ubicom, Inc.
   6  *
   7  * This file is part of the Ubicom32 Linux Kernel Port.
   8  *
   9  * The Ubicom32 Linux Kernel Port is free software: you can redistribute
  10  * it and/or modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation, either version 2 of the
  12  * License, or (at your option) any later version.
  13  *
  14  * The Ubicom32 Linux Kernel Port is distributed in the hope that it
  15  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  16  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  17  * the GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with the Ubicom32 Linux Kernel Port.  If not,
  21  * see <http://www.gnu.org/licenses/>.
  22  *
  23  * Ubicom32 implementation derived from (with many thanks):
  24  *   arch/m68knommu
  25  *   arch/blackfin
  26  *   arch/parisc
  27  */
  28 #ifndef _ASM_UBICOM32_DELAY_H
  29 #define _ASM_UBICOM32_DELAY_H
  30
  31 #include <asm/param.h>
  32 #include <asm/ip5000.h>
  33
  34 static inline void __delay(unsigned long loops)
  35 {
  36         if (loops == 0) {
  37                 return;
  38         }
  39
  40         asm volatile (
  41         "1:     add.4   %0, #-1, %0             \n\t"
  42         "       jmpne.t 1b                      \n\t"
  43         : "+d" (loops)
  44         );
  45 }
  46
  47 /*
  48  *      Ubicom32 processor uses fixed 12MHz external OSC.
  49  *      So we use that as reference to count 12 cycles/us
  50  */
  51
  52 extern unsigned long loops_per_jiffy;
  53
  54 static inline void _udelay(unsigned long usecs)
  55 {
  56 #if defined(CONFIG_UBICOM32_V4) || defined(CONFIG_UBICOM32_V3)
  57         asm volatile (
  58                 "       add.4           d15, 0(%0), %1                  \n\t"
  59                 "       sub.4           #0, 0(%0), d15                  \n\t"
  60                 "       jmpmi.w.f       .-4                             \n\t"
  61                 :
  62                 : "a"(TIMER_BASE + TIMER_MPTVAL), "d"(usecs * (12000000/1000000))
  63                 : "d15"
  64         );
  65 #else
  66         BUG();
  67 #endif
  68 }
  69
  70 /*
  71  *      Moved the udelay() function into library code, no longer inlined.
  72  */
  73 extern void udelay(unsigned long usecs);
  74
  75 #endif /* _ASM_UBICOM32_DELAY_H */