reset.c

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/*
 * Reset a Jazz machine.
 *
 * We don't trust the firmware so we do it the classic way by poking and
 * stabbing at the keyboard controller ...
 */
#include <linux/jiffies.h>
#include <asm/jazz.h>

#define KBD_STAT_IBF        0x02    /* Keyboard input buffer full */

static void jazz_write_output(unsigned char val)
{
    int status;

    do {
        status = jazz_kh->command;
    } while (status & KBD_STAT_IBF);
    jazz_kh->data = val;
}

static void jazz_write_command(unsigned char val)
{
    int status;

    do {
        status = jazz_kh->command;
    } while (status & KBD_STAT_IBF);
    jazz_kh->command = val;
}

static unsigned char jazz_read_status(void)
{
    return jazz_kh->command;
}

static inline void kb_wait(void)
{
    unsigned long start = jiffies;
    unsigned long timeout = start + HZ/2;

    do {
        if (! (jazz_read_status() & 0x02))
            return;
    } while (time_before_eq(jiffies, timeout));
}

void jazz_machine_restart(char *command)
{
    while(1) {
        kb_wait();
        jazz_write_command(0xd1);
        kb_wait();
        jazz_write_output(0x00);
    }
}