linux/arch/mips/lantiq/xway/reset.c

/*
 *  This program is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU General Public License version 2 as published
 *  by the Free Software Foundation.
 *
 *  Copyright (C) 2010 John Crispin <blogic@openwrt.org>
 */

#include <linux/init.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/pm.h>
#include <linux/export.h>
#include <linux/delay.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>

#include <asm/reboot.h>

#include <lantiq_soc.h>

#include "../prom.h"

#define ltq_rcu_w32(x, y)	ltq_w32((x), ltq_rcu_membase + (y))
#define ltq_rcu_r32(x)		ltq_r32(ltq_rcu_membase + (x))

/* reset request register */
#define RCU_RST_REQ		0x0010
/* reset status register */
#define RCU_RST_STAT		0x0014

/* reboot bit */
#define RCU_RD_SRST		BIT(30)
/* reset cause */
#define RCU_STAT_SHIFT		26
/* boot selection */
#define RCU_BOOT_SEL_SHIFT	26
#define RCU_BOOT_SEL_MASK	0x7

/* remapped base addr of the reset control unit */
static void __iomem *ltq_rcu_membase;

/* This function is used by the watchdog driver */
int ltq_reset_cause(void)
{
	u32 val = ltq_rcu_r32(RCU_RST_STAT);
	return val >> RCU_STAT_SHIFT;
}
EXPORT_SYMBOL_GPL(ltq_reset_cause);

/* allow platform code to find out what source we booted from */
unsigned char ltq_boot_select(void)
{
	u32 val = ltq_rcu_r32(RCU_RST_STAT);
	return (val >> RCU_BOOT_SEL_SHIFT) & RCU_BOOT_SEL_MASK;
}

/* reset a io domain for u micro seconds */
void ltq_reset_once(unsigned int module, ulong u)
{
	ltq_rcu_w32(ltq_rcu_r32(RCU_RST_REQ) | module, RCU_RST_REQ);
	udelay(u);
	ltq_rcu_w32(ltq_rcu_r32(RCU_RST_REQ) & ~module, RCU_RST_REQ);
}

static void ltq_machine_restart(char *command)
{
	local_irq_disable();
	ltq_rcu_w32(ltq_rcu_r32(RCU_RST_REQ) | RCU_RD_SRST, RCU_RST_REQ);
	unreachable();
}

static void ltq_machine_halt(void)
{
	local_irq_disable();
	unreachable();
}

static void ltq_machine_power_off(void)
{
	local_irq_disable();
	unreachable();
}

static int __init mips_reboot_setup(void)
{
	struct resource res;
	struct device_node *np =
		of_find_compatible_node(NULL, NULL, "lantiq,rcu-xway");

	/* check if all the reset register range is available */
	if (!np)
		panic("Failed to load reset resources from devicetree");

	if (of_address_to_resource(np, 0, &res))
		panic("Failed to get rcu memory range");

	if (request_mem_region(res.start, resource_size(&res), res.name) < 0)
		pr_err("Failed to request rcu memory");

	ltq_rcu_membase = ioremap_nocache(res.start, resource_size(&res));
	if (!ltq_rcu_membase)
		panic("Failed to remap core memory");

	_machine_restart = ltq_machine_restart;
	_machine_halt = ltq_machine_halt;
	pm_power_off = ltq_machine_power_off;

	return 0;
}

arch_initcall(mips_reboot_setup);