rtas.c

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/*
 *
 * 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 <asm/prom.h>
#include <asm/rtas.h>
#include <asm/semaphore.h>
#include <asm/machdep.h>
#include <asm/page.h>
#include <asm/param.h>
#include <asm/system.h>
#include <asm/abs_addr.h>
#include <asm/udbg.h>
#include <asm/delay.h>
#include <asm/uaccess.h>
#include <asm/systemcfg.h>

struct flash_block_list_header rtas_firmware_flash_list = {0, NULL};

struct rtas_t rtas = { 
	.lock = SPIN_LOCK_UNLOCKED
};

EXPORT_SYMBOL(rtas);

char rtas_err_buf[RTAS_ERROR_LOG_MAX];

DEFINE_SPINLOCK(rtas_data_buf_lock);
char rtas_data_buf[RTAS_DATA_BUF_SIZE]__page_aligned;
unsigned long rtas_rmo_buf;

void
call_rtas_display_status(unsigned char c)
{
	struct rtas_args *args = &rtas.args;
	unsigned long s;

	if (!rtas.base)
		return;
	spin_lock_irqsave(&rtas.lock, s);

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

	enter_rtas(__pa(args));

	spin_unlock_irqrestore(&rtas.lock, s);
}

void
call_rtas_display_status_delay(unsigned 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;
		udelay(500000);
		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);
		}
	}
}

int
rtas_token(const char *service)
{
	int *tokp;
	if (rtas.dev == NULL) {
		PPCDBG(PPCDBG_RTAS,"\tNo rtas device in device-tree...\n");
		return RTAS_UNKNOWN_SERVICE;
	}
	tokp = (int *) get_property(rtas.dev, service, NULL);
	return tokp ? *tokp : RTAS_UNKNOWN_SERVICE;
}

/*
 * Return the firmware-specified size of the error log buffer
 *  for all rtas calls that require an error buffer argument.
 *  This includes 'check-exception' and 'rtas-last-error'.
 */
int rtas_get_error_log_max(void)
{
	static int rtas_error_log_max;
	if (rtas_error_log_max)
		return rtas_error_log_max;

	rtas_error_log_max = rtas_token ("rtas-error-log-max");
	if ((rtas_error_log_max == RTAS_UNKNOWN_SERVICE) ||
	    (rtas_error_log_max > RTAS_ERROR_LOG_MAX)) {
		printk (KERN_WARNING "RTAS: bad log buffer size %d\n", rtas_error_log_max);
		rtas_error_log_max = RTAS_ERROR_LOG_MAX;
	}
	return rtas_error_log_max;
}


/** Return a copy of the detailed error text associated with the
 *  most recent failed call to rtas.  Because the error text
 *  might go stale if there are any other intervening rtas calls,
 *  this routine must be called atomically with whatever produced
 *  the error (i.e. with rtas.lock still held from the previous call).
 */
static int
__fetch_rtas_last_error(void)
{
	struct rtas_args err_args, save_args;
	u32 bufsz;

	bufsz = rtas_get_error_log_max();

	err_args.token = rtas_token("rtas-last-error");
	err_args.nargs = 2;
	err_args.nret = 1;

	err_args.args[0] = (rtas_arg_t)__pa(rtas_err_buf);
	err_args.args[1] = bufsz;
	err_args.args[2] = 0;

	save_args = rtas.args;
	rtas.args = err_args;

	enter_rtas(__pa(&rtas.args));

	err_args = rtas.args;
	rtas.args = save_args;

	return err_args.args[2];
}

int rtas_call(int token, int nargs, int nret, int *outputs, ...)
{
	va_list list;
	int i, logit = 0;
	unsigned long s;
	struct rtas_args *rtas_args;
	char * buff_copy = NULL;
	int ret;

	PPCDBG(PPCDBG_RTAS, "Entering rtas_call\n");
	PPCDBG(PPCDBG_RTAS, "\ttoken    = 0x%x\n", token);
	PPCDBG(PPCDBG_RTAS, "\tnargs    = %d\n", nargs);
	PPCDBG(PPCDBG_RTAS, "\tnret     = %d\n", nret);
	PPCDBG(PPCDBG_RTAS, "\t&outputs = 0x%lx\n", outputs);
	if (token == RTAS_UNKNOWN_SERVICE)
		return -1;

	/* Gotta do something different here, use global lock for now... */
	spin_lock_irqsave(&rtas.lock, s);
	rtas_args = &rtas.args;

	rtas_args->token = token;
	rtas_args->nargs = nargs;
	rtas_args->nret  = nret;
	rtas_args->rets  = (rtas_arg_t *)&(rtas_args->args[nargs]);
	va_start(list, outputs);
	for (i = 0; i < nargs; ++i) {
		rtas_args->args[i] = va_arg(list, rtas_arg_t);
		PPCDBG(PPCDBG_RTAS, "\tnarg[%d] = 0x%x\n", i, rtas_args->args[i]);
	}
	va_end(list);

	for (i = 0; i < nret; ++i)
		rtas_args->rets[i] = 0;

	PPCDBG(PPCDBG_RTAS, "\tentering rtas with 0x%lx\n",
		__pa(rtas_args));
	enter_rtas(__pa(rtas_args));
	PPCDBG(PPCDBG_RTAS, "\treturned from rtas ...\n");

	/* A -1 return code indicates that the last command couldn't
	   be completed due to a hardware error. */
	if (rtas_args->rets[0] == -1)
		logit = (__fetch_rtas_last_error() == 0);

	ifppcdebug(PPCDBG_RTAS) {
		for(i=0; i < nret ;i++)
			udbg_printf("\tnret[%d] = 0x%lx\n", i, (ulong)rtas_args->rets[i]);
	}

	if (nret > 1 && outputs != NULL)
		for (i = 0; i < nret-1; ++i)
			outputs[i] = rtas_args->rets[i+1];
	ret = (nret > 0)? rtas_args->rets[0]: 0;

	/* Log the error in the unlikely case that there was one. */
	if (unlikely(logit)) {
		buff_copy = rtas_err_buf;
		if (mem_init_done) {
			buff_copy = kmalloc(RTAS_ERROR_LOG_MAX, GFP_ATOMIC);
			if (buff_copy)
				memcpy(buff_copy, rtas_err_buf,
				       RTAS_ERROR_LOG_MAX);
		}
	}

	/* Gotta do something different here, use global lock for now... */
	spin_unlock_irqrestore(&rtas.lock, s);

	if (buff_copy) {
		log_error(buff_copy, ERR_TYPE_RTAS_LOG, 0);
		if (mem_init_done)
			kfree(buff_copy);
	}
	return ret;
}

/* Given an RTAS status code of 990n compute the hinted delay of 10^n
 * (last digit) milliseconds.  For now we bound at n=5 (100 sec).
 */
unsigned int
rtas_extended_busy_delay_time(int status)
{
	int order = status - 9900;
	unsigned long ms;

	if (order < 0)
		order = 0;	/* RTC depends on this for -2 clock busy */
	else if (order > 5)
		order = 5;	/* bound */

	/* Use microseconds for reasonable accuracy */
	for (ms=1; order > 0; order--)
		ms *= 10;

	return ms; 
}

int
rtas_get_power_level(int powerdomain, int *level)
{
	int token = rtas_token("get-power-level");
	int rc;

	if (token == RTAS_UNKNOWN_SERVICE)
		return RTAS_UNKNOWN_OP;

	while ((rc = rtas_call(token, 1, 2, level, powerdomain)) == RTAS_BUSY)
		udelay(1);
	return rc;
}

int
rtas_set_power_level(int powerdomain, int level, int *setlevel)
{
	int token = rtas_token("set-power-level");
	unsigned int wait_time;
	int rc;

	if (token == RTAS_UNKNOWN_SERVICE)
		return RTAS_UNKNOWN_OP;

	while (1) {
		rc = rtas_call(token, 2, 2, setlevel, powerdomain, level);
		if (rc == RTAS_BUSY)
			udelay(1);
		else if (rtas_is_extended_busy(rc)) {
			wait_time = rtas_extended_busy_delay_time(rc);
			udelay(wait_time * 1000);
		} else
			break;
	}
	return rc;
}

int
rtas_get_sensor(int sensor, int index, int *state)
{
	int token = rtas_token("get-sensor-state");
	unsigned int wait_time;
	int rc;

	if (token == RTAS_UNKNOWN_SERVICE)
		return RTAS_UNKNOWN_OP;

	while (1) {
		rc = rtas_call(token, 2, 2, state, sensor, index);
		if (rc == RTAS_BUSY)
			udelay(1);
		else if (rtas_is_extended_busy(rc)) {
			wait_time = rtas_extended_busy_delay_time(rc);
			udelay(wait_time * 1000);