arch/blackfin/kernel/reboot.c

   1 /*
   2  * arch/blackfin/kernel/reboot.c - handle shutdown/reboot
   3  *
   4  * Copyright 2004-2007 Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2 or later.
   7  */
   8
   9 #include <linux/interrupt.h>
  10 #include <asm/bfin-global.h>
  11 #include <asm/reboot.h>
  12 #include <asm/system.h>
  13
  14 #if defined(BF537_FAMILY) || defined(BF533_FAMILY) || defined(BF527_FAMILY)
  15 #define SYSCR_VAL       0x0
  16 #elif defined(BF561_FAMILY)
  17 #define SYSCR_VAL       0x20
  18 #elif defined(BF548_FAMILY)
  19 #define SYSCR_VAL       0x10
  20 #endif
  21
  22 /*
  23  * Delay min 5 SCLK cycles using worst case CCLK/SCLK ratio (15)
  24  */
  25 #define SWRST_DELAY     (5 * 15)
  26
  27 /* A system soft reset makes external memory unusable
  28  * so force this function into L1.
  29  */
  30 __attribute__((l1_text))
  31 void bfin_reset(void)
  32 {
  33         /* force BMODE and disable Core B (as needed) */
  34         bfin_write_SYSCR(SYSCR_VAL);
  35
  36         /* we use asm ssync here because it's save and we save some L1 */
  37         asm("ssync;");
  38
  39         while (1) {
  40                 /* initiate system soft reset with magic 0x7 */
  41                 bfin_write_SWRST(0x7);
  42
  43                 /* Wait for System reset to actually reset, needs to be 5 SCLKs, */
  44                 /* Assume CCLK / SCLK ratio is worst case (15), and use 5*15     */
  45
  46                 asm("LSETUP(.Lfoo,.Lfoo) LC0 = %0\n .Lfoo: NOP;\n"
  47                  : : "a" (SWRST_DELAY) : "LC0", "LT0", "LB0");
  48
  49                 /* clear system soft reset */
  50                 bfin_write_SWRST(0);
  51                 asm("ssync;");
  52                 /* issue core reset */
  53                 asm("raise 1");
  54         }
  55 }
  56
  57 __attribute__((weak))
  58 void native_machine_restart(char *cmd)
  59 {
  60 }
  61
  62 void machine_restart(char *cmd)
  63 {
  64         native_machine_restart(cmd);
  65         local_irq_disable();
  66         bfin_reset();
  67 }
  68
  69 __attribute__((weak))
  70 void native_machine_halt(void)
  71 {
  72         idle_with_irq_disabled();
  73 }
  74
  75 void machine_halt(void)
  76 {
  77         native_machine_halt();
  78 }
  79
  80 __attribute__((weak))
  81 void native_machine_power_off(void)
  82 {
  83         idle_with_irq_disabled();
  84 }
  85
  86 void machine_power_off(void)
  87 {
  88         native_machine_power_off();
  89 }