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 KBD_STAT_IBF            0x02    /* Keyboard input buffer full */
  15
  16 static void jazz_write_output(unsigned char val)
  17 {
  18         int status;
  19
  20         do {
  21                 status = jazz_kh->command;
  22         } while (status & KBD_STAT_IBF);
  23         jazz_kh->data = val;
  24 }
  25
  26 static void jazz_write_command(unsigned char val)
  27 {
  28         int status;
  29
  30         do {
  31                 status = jazz_kh->command;
  32         } while (status & KBD_STAT_IBF);
  33         jazz_kh->command = val;
  34 }
  35
  36 static unsigned char jazz_read_status(void)
  37 {
  38         return jazz_kh->command;
  39 }
  40
  41 static inline void kb_wait(void)
  42 {
  43         unsigned long start = jiffies;
  44         unsigned long timeout = start + HZ/2;
  45
  46         do {
  47                 if (! (jazz_read_status() & 0x02))
  48                         return;
  49         } while (time_before_eq(jiffies, timeout));
  50 }
  51
  52 void jazz_machine_restart(char *command)
  53 {
  54         while(1) {
  55                 kb_wait();
  56                 jazz_write_command (0xd1);
  57                 kb_wait();
  58                 jazz_write_output (0x00);
  59         }
  60 }
  61
  62 void jazz_machine_halt(void)
  63 {
  64 }
  65
  66 void jazz_machine_power_off(void)
  67 {
  68         /* Jazz machines don't have a software power switch */
  69 }