Blackfin arch: Workaround reboot bug, issue SSYNC at the start of bfin_reset

/*

 * arch/blackfin/kernel/reboot.c - handle shutdown/reboot

 *

 * Copyright 2004-2007 Analog Devices Inc.

 *

 * Licensed under the GPL-2 or later.

 */

#include <linux/interrupt.h>

#include <asm/bfin-global.h>

#include <asm/reboot.h>

#include <asm/system.h>

#if defined(BF537_FAMILY) || defined(BF533_FAMILY)

#define SYSCR_VAL 	0x0

#elif defined(BF561_FAMILY)

#define SYSCR_VAL 	0x20

#elif defined(BF548_FAMILY)

#define SYSCR_VAL 	0x10

#endif

/* A system soft reset makes external memory unusable

 * so force this function into L1.

 */

__attribute__((l1_text))

void bfin_reset(void)

{

	/* force BMODE and disable Core B (as needed) */

	bfin_write_SYSCR(SYSCR_VAL);

	/* we use asm ssync here because it's save and we save some L1 */

	asm("ssync;");

	while (1) {

		/* initiate system soft reset with magic 0x7 */

		bfin_write_SWRST(0x7);

		asm("ssync;");

		/* clear system soft reset */

		bfin_write_SWRST(0);

		asm("ssync;");

		/* issue core reset */

		asm("raise 1");

	}

}

__attribute__((weak))

void native_machine_restart(char *cmd)

{

}

void machine_restart(char *cmd)

{

	native_machine_restart(cmd);

	local_irq_disable();

	bfin_reset();

}

__attribute__((weak))

void native_machine_halt(void)

{

	idle_with_irq_disabled();

}

void machine_halt(void)

{

	native_machine_halt();

}

__attribute__((weak))

void native_machine_power_off(void)

{

	idle_with_irq_disabled();

}

void machine_power_off(void)

{

	native_machine_power_off();

}

/*

 * include/asm-blackfin/reboot.h - shutdown/reboot header

 *

 * Copyright 2004-2007 Analog Devices Inc.

 *

 * Licensed under the GPL-2 or later.

 */

#ifndef __ASM_REBOOT_H__

#define __ASM_REBOOT_H__

/* optional board specific hooks */

extern void native_machine_restart(char *cmd);

extern void native_machine_halt(void);

extern void native_machine_power_off(void);

/* common reboot workarounds */

extern void bfin_gpio_reset_spi0_ssel1(void);

#endif