path: root/arch/powerpc/kernel/rtas.c

/*
 *
 * Procedures for interfacing to the RTAS on CHRP machines.
 *
 * Peter Bergner, IBM	March 2001.
 * Copyright (C) 2001 IBM.
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#include <stdarg.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/capability.h>
#include <linux/delay.h>
#include <linux/smp.h>
#include <linux/completion.h>
#include <linux/cpumask.h>
#include <linux/lmb.h>

#include <asm/prom.h>
#include <asm/rtas.h>
#include <asm/hvcall.h>
#include <asm/machdep.h>
#include <asm/firmware.h>
#include <asm/page.h>
#include <asm/param.h>
#include <asm/system.h>
#include <asm/delay.h>
#include <asm/uaccess.h>
#include <asm/udbg.h>
#include <asm/syscalls.h>
#include <asm/smp.h>
#include <asm/atomic.h>
#include <asm/time.h>
#include <asm/mmu.h>

struct rtas_t rtas = {
	.lock = __ARCH_SPIN_LOCK_UNLOCKED
};
EXPORT_SYMBOL(rtas);

struct rtas_suspend_me_data {
	atomic_t working; /* number of cpus accessing this struct */
	atomic_t done;
	int token; /* ibm,suspend-me */
	int error;
	struct completion *complete; /* wait on this until working == 0 */
};

DEFINE_SPINLOCK(rtas_data_buf_lock);
EXPORT_SYMBOL(rtas_data_buf_lock);

char rtas_data_buf[RTAS_DATA_BUF_SIZE] __cacheline_aligned;
EXPORT_SYMBOL(rtas_data_buf);

unsigned long rtas_rmo_buf;

/*
 * If non-NULL, this gets called when the kernel terminates.
 * This is done like this so rtas_flash can be a module.
 */
void (*rtas_flash_term_hook)(int);
EXPORT_SYMBOL(rtas_flash_term_hook);

/* RTAS use home made raw locking instead of spin_lock_irqsave
 * because those can be called from within really nasty contexts
 * such as having the timebase stopped which would lockup with
 * normal locks and spinlock debugging enabled
 */
static unsigned long lock_rtas(void)
{
	unsigned long flags;

	local_irq_save(flags);
	preempt_disable();
	arch_spin_lock_flags(&rtas.lock, flags);
	return flags;
}

static void unlock_rtas(unsigned long flags)
{
	arch_spin_unlock(&rtas.lock);
	local_irq_restore(flags);
	preempt_enable();
}

/*
 * call_rtas_display_status and call_rtas_display_status_delay
 * are designed only for very early low-level debugging, which
 * is why the token is hard-coded to 10.
 */
static void call_rtas_display_status(char c)
{
	struct rtas_args *args = &rtas.args;
	unsigned long s;

	if (!rtas.base)
		return;
	s = lock_rtas();

	args->token = 10;
	args->nargs = 1;
	args->nret  = 1;
	args->rets  = (rtas_arg_t *)&(args->args[1]);
	args->args[0] = (unsigned char)c;

	enter_rtas(__pa(args));

	unlock_rtas(s);
}

static void call_rtas_display_status_delay(char c)
{
	static int pending_newline = 0;  /* did last write end with unprinted newline? */
	static int width = 16;

	if (c == '\n') {	
		while (width-- > 0)
			call_rtas_display_status(' ');
		width = 16;
		mdelay(500);
		pending_newline = 1;
	} else {
		if (pending_newline) {
			call_rtas_display_status('\r');
			call_rtas_display_status('\n');
		} 
		pending_newline = 0;
		if (width--) {
			call_rtas_display_status(c);
			udelay(10000);
		}
	}
}

void __init udbg_init_rtas_panel(void)
{
	udbg_putc = call_rtas_display_status_delay;
}

#ifdef CONFIG_UDBG_RTAS_CONSOLE

/* If you think you're dying before early_init_dt_scan_rtas() does its
 * work, you can hard code the token values for your firmware here and
 * hardcode rtas.base/entry etc.
 */
static unsigned int rtas_putchar_token = RTAS_UNKNOWN_SERVICE;
static unsigned int rtas_getchar_token = RTAS_UNKNOWN_SERVICE;

static void udbg_rtascon_putc(char c)
{
	int tries;

	if (!rtas.base)
		return;

	/* Add CRs before LFs */
	if (c == '\n')
		udbg_rtascon_putc('\r');

	/* if there is more than one character to be displayed, wait a bit */
	for (tries = 0; tries < 16; tries++) {
		if (rtas_call(rtas_putchar_token, 1, 1, NULL, c) == 0)
			break;
		udelay(1000);
	}
}

static int udbg_rtascon_getc_poll(void)
{
	int c;

	if (!rtas.base)
		return -1;

	if (rtas_call(rtas_getchar_token, 0, 2, &c))
		return -1;

	return c;
}

static int udbg_rtascon_getc(void)
{
	int c;

	while ((