rt-thread/libcpu/arm/arm926/cpuport.c

/*
 * File      : cpu.c
 * This file is part of RT-Thread RTOS
 * COPYRIGHT (C) 2006, RT-Thread Develop Team
 *
 * The license and distribution terms for this file may be
 * found in the file LICENSE in this distribution or at
 * http://openlab.rt-thread.com/license/LICENSE
 *
 * Change Logs:
 * Date           Author       Notes
 * 2011-01-13     weety      modified from mini2440
 */

#include <rthw.h>
#include <rtthread.h>

#define ICACHE_MASK	(rt_uint32_t)(1 << 12)
#define DCACHE_MASK	(rt_uint32_t)(1 << 2)

extern void machine_reset(void);
extern void machine_shutdown(void);

#ifdef __GNUC__
rt_inline rt_uint32_t cp15_rd(void)
{
	rt_uint32_t i;

	asm ("mrc p15, 0, %0, c1, c0, 0":"=r" (i));
	return i;
}

rt_inline void cache_enable(rt_uint32_t bit)
{
	__asm__ __volatile__(			\
		"mrc  p15,0,r0,c1,c0,0\n\t"	\
		"orr  r0,r0,%0\n\t"			\
	   	"mcr  p15,0,r0,c1,c0,0"		\
		:							\
		:"r" (bit)					\
		:"memory");
}

rt_inline void cache_disable(rt_uint32_t bit)
{
	__asm__ __volatile__(			\
		"mrc  p15,0,r0,c1,c0,0\n\t"	\
		"bic  r0,r0,%0\n\t"			\
		"mcr  p15,0,r0,c1,c0,0"		\
		:							\
		:"r" (bit)					\
		:"memory");
}
#endif

#ifdef __CC_ARM
rt_inline rt_uint32_t cp15_rd(void)
{
	rt_uint32_t i;

	__asm
	{
		mrc p15, 0, i, c1, c0, 0
	}

	return i;
}

rt_inline void cache_enable(rt_uint32_t bit)
{
	rt_uint32_t value;

	__asm
	{
		mrc p15, 0, value, c1, c0, 0
		orr value, value, bit
		mcr p15, 0, value, c1, c0, 0
	}
}

rt_inline void cache_disable(rt_uint32_t bit)
{
	rt_uint32_t value;

	__asm
	{
		mrc p15, 0, value, c1, c0, 0
		bic value, value, bit
		mcr p15, 0, value, c1, c0, 0
	}
}
#endif

/**
 * enable I-Cache
 *
 */
void rt_hw_cpu_icache_enable()
{
	cache_enable(ICACHE_MASK);
}

/**
 * disable I-Cache
 *
 */
void rt_hw_cpu_icache_disable()
{
	cache_disable(ICACHE_MASK);
}

/**
 * return the status of I-Cache
 *
 */
rt_base_t rt_hw_cpu_icache_status()
{
	return (cp15_rd() & ICACHE_MASK);
}

/**
 * enable D-Cache
 *
 */
void rt_hw_cpu_dcache_enable()
{
	cache_enable(DCACHE_MASK);
}

/**
 * disable D-Cache
 *
 */
void rt_hw_cpu_dcache_disable()
{
	cache_disable(DCACHE_MASK);
}

/**
 * return the status of D-Cache
 *
 */
rt_base_t rt_hw_cpu_dcache_status()
{
	return (cp15_rd() & DCACHE_MASK);
}

/**
 * reset cpu by dog's time-out
 *
 */
void rt_hw_cpu_reset()
{
	
	rt_kprintf("Restarting system...\n");
	machine_reset();

	while(1);	/* loop forever and wait for reset to happen */

	/* NEVER REACHED */
}

/**
 *  shutdown CPU
 *
 */
void rt_hw_cpu_shutdown()
{
	rt_uint32_t level;
	rt_kprintf("shutdown...\n");

	level = rt_hw_interrupt_disable();
	machine_shutdown();
	while (level)
	{
		RT_ASSERT(0);
	}
}

#ifdef RT_USING_CPU_FFS
/**
 * This function finds the first bit set (beginning with the least significant bit) 
 * in value and return the index of that bit.
 *
 * Bits are numbered starting at 1 (the least significant bit).  A return value of 
 * zero from any of these functions means that the argument was zero.
 * 
 * @return return the index of the first bit set. If value is 0, then this function 
 * shall return 0.
 */
#if defined(__CC_ARM)
int __rt_ffs(int value)
{
	register rt_uint32_t x;

	if (value == 0)
		return value;
	
	__asm
	{
		rsb x, value, #0
		and x, x, value
		clz x, x
		rsb x, x, #32
	}

	return x;
}
#elif defined(__IAR_SYSTEMS_ICC__)
int __rt_ffs(int value)
{
	if (value == 0)
		return value;

	__ASM("RSB  r4, r0, #0");
	__ASM("AND  r4, r4, r0");
	__ASM("CLZ  r4, r4");
	__ASM("RSB  r0, r4, #32");
}
#elif defined(__GNUC__)
int __rt_ffs(int value)
{
	if (value == 0)
		return value;

	value &= (-value);
	asm ("clz %0, %1": "=r"(value) :"r"(value));

	return (32 - value);
}
#endif

#endif


/*@}*/