lib_ppc/interrupts.c

   1 /*
   2  * (C) Copyright 2000-2002
   3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   4  *
   5  * (C) Copyright 2003
   6  * Gleb Natapov <gnatapov@mrv.com>
   7  *
   8  * See file CREDITS for list of people who contributed to this
   9  * project.
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License as
  13  * published by the Free Software Foundation; either version 2 of
  14  * the License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  24  * MA 02111-1307 USA
  25  */
  26
  27 #include <common.h>
  28 #include <asm/processor.h>
  29 #include <watchdog.h>
  30 #ifdef CONFIG_STATUS_LED
  31 #include <status_led.h>
  32 #endif
  33
  34 #ifdef CONFIG_SHOW_ACTIVITY
  35         extern void board_show_activity (ulong);
  36 #endif /* CONFIG_SHOW_ACTIVITY */
  37
  38 #ifndef CFG_WATCHDOG_FREQ
  39 #define CFG_WATCHDOG_FREQ (CFG_HZ / 2)
  40 #endif
  41
  42 extern int interrupt_init_cpu (unsigned *);
  43 extern void timer_interrupt_cpu (struct pt_regs *);
  44
  45 static unsigned decrementer_count; /* count value for 1e6/HZ microseconds */
  46
  47 static __inline__ unsigned long get_msr (void)
  48 {
  49         unsigned long msr;
  50
  51         asm volatile ("mfmsr %0":"=r" (msr):);
  52
  53         return msr;
  54 }
  55
  56 static __inline__ void set_msr (unsigned long msr)
  57 {
  58         asm volatile ("mtmsr %0"::"r" (msr));
  59 }
  60
  61 static __inline__ unsigned long get_dec (void)
  62 {
  63         unsigned long val;
  64
  65         asm volatile ("mfdec %0":"=r" (val):);
  66
  67         return val;
  68 }
  69
  70
  71 static __inline__ void set_dec (unsigned long val)
  72 {
  73         if (val)
  74                 asm volatile ("mtdec %0"::"r" (val));
  75 }
  76
  77
  78 void enable_interrupts (void)
  79 {
  80         set_msr (get_msr () | MSR_EE);
  81 }
  82
  83 /* returns flag if MSR_EE was set before */
  84 int disable_interrupts (void)
  85 {
  86         ulong msr = get_msr ();
  87
  88         set_msr (msr & ~MSR_EE);
  89         return ((msr & MSR_EE) != 0);
  90 }
  91
  92 int interrupt_init (void)
  93 {
  94         int ret;
  95
  96         /* call cpu specific function from $(CPU)/interrupts.c */
  97         ret = interrupt_init_cpu (&decrementer_count);
  98
  99         if (ret)
 100                 return ret;
 101
 102         set_dec (decrementer_count);
 103
 104         set_msr (get_msr () | MSR_EE);
 105
 106         return (0);
 107 }
 108
 109 static volatile ulong timestamp = 0;
 110
 111 void timer_interrupt (struct pt_regs *regs)
 112 {
 113         /* call cpu specific function from $(CPU)/interrupts.c */
 114         timer_interrupt_cpu (regs);
 115
 116         /* Restore Decrementer Count */
 117         set_dec (decrementer_count);
 118
 119         timestamp++;
 120
 121 #if defined(CONFIG_WATCHDOG) || defined (CONFIG_HW_WATCHDOG)
 122         if ((timestamp % (CFG_WATCHDOG_FREQ)) == 0)
 123                 WATCHDOG_RESET ();
 124 #endif    /* CONFIG_WATCHDOG || CONFIG_HW_WATCHDOG */
 125
 126 #ifdef CONFIG_STATUS_LED
 127         status_led_tick (timestamp);
 128 #endif /* CONFIG_STATUS_LED */
 129
 130 #ifdef CONFIG_SHOW_ACTIVITY
 131         board_show_activity (timestamp);
 132 #endif /* CONFIG_SHOW_ACTIVITY */
 133 }
 134
 135 void reset_timer (void)
 136 {
 137         timestamp = 0;
 138 }
 139
 140 ulong get_timer (ulong base)
 141 {
 142         return (timestamp - base);
 143 }
 144
 145 void set_timer (ulong t)
 146 {
 147         timestamp = t;
 148 }