arch/mips/jazz/reset.c

   1 /*
   2  * Reset a Jazz machine.
   3  *
   4  * We don't trust the firmware so we do it the classic way by poking and
   5  * stabbing at the keyboard controller ...
   6  */
   7 #include <linux/jiffies.h>
   8 #include <asm/jazz.h>
   9 #include <asm/io.h>
  10 #include <asm/system.h>
  11 #include <asm/reboot.h>
  12 #include <asm/delay.h>
  13
  14 #define jazz_kh ((keyboard_hardware *) JAZZ_KEYBOARD_ADDRESS)
  15
  16 #define KBD_STAT_IBF            0x02    /* Keyboard input buffer full */
  17
  18 static void jazz_write_output(unsigned char val)
  19 {
  20         int status;
  21
  22         do {
  23                 status = jazz_kh->command;
  24         } while (status & KBD_STAT_IBF);
  25         jazz_kh->data = val;
  26 }
  27
  28 static void jazz_write_command(unsigned char val)
  29 {
  30         int status;
  31
  32         do {
  33                 status = jazz_kh->command;
  34         } while (status & KBD_STAT_IBF);
  35         jazz_kh->command = val;
  36 }
  37
  38 static unsigned char jazz_read_status(void)
  39 {
  40         return jazz_kh->command;
  41 }
  42
  43 static inline void kb_wait(void)
  44 {
  45         unsigned long start = jiffies;
  46         unsigned long timeout = start + HZ/2;
  47
  48         do {
  49                 if (! (jazz_read_status() & 0x02))
  50                         return;
  51         } while (time_before_eq(jiffies, timeout));
  52 }
  53
  54 void jazz_machine_restart(char *command)
  55 {
  56         while(1) {
  57                 kb_wait();
  58                 jazz_write_command (0xd1);
  59                 kb_wait();
  60                 jazz_write_output (0x00);
  61         }
  62 }
  63
  64 void jazz_machine_halt(void)
  65 {
  66 }
  67
  68 void jazz_machine_power_off(void)
  69 {
  70         /* Jazz machines don't have a software power switch */
  71 }