bit操作

#define BIT(nr) (1UL << (nr))
#define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG))
#define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
#define BITS_PER_BYTE 8
#define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))

#define DECLARE_BITMAP(name,bits) /
unsigned long name[BITS_TO_LONGS(bits)]

039

/**

040	* Bitmap of enabled clocks, excluding ACPU which is always

041

* enabled

042

*/

043	static DECLARE_BITMAP(clock_map_enabled, NR_CLKS);

044	static DEFINE_SPINLOCK(clock_map_lock);

clock_map_enabled[BIT_WORD(clk->id)] &= ~BIT_MASK(clk->id);

clock_map_enabled[BIT_WORD(clk->id)] |= BIT_MASK(clk->id);

int clk_enable(struct clk *clk)

076

{

077	unsigned long flags;

078	spin_lock_irqsave(&clocks_lock, flags);

079	clk->count++;

080	if (clk->count == 1) {

081	clk->ops->enable(clk->id);

082	spin_lock(&clock_map_lock);

083	clock_map_enabled[BIT_WORD(clk->id)] |= BIT_MASK(clk->id);

084	spin_unlock(&clock_map_lock);

085

}

086	spin_unlock_irqrestore(&clocks_lock, flags);

087

return 0;

088

}

089	EXPORT_SYMBOL(clk_enable);

090

091	void clk_disable(struct clk *clk)

092

{

093	unsigned long flags;

094	spin_lock_irqsave(&clocks_lock, flags);

095	BUG_ON(clk->count == 0);

096	clk->count--;

097	if (clk->count == 0) {

098	clk->ops->disable(clk->id);

099	spin_lock(&clock_map_lock);

100	clock_map_enabled[BIT_WORD(clk->id)] &= ~BIT_MASK(clk->id);

101	spin_unlock(&clock_map_lock);

102

}

103	spin_unlock_irqrestore(&clocks_lock, flags);

104

}

105	EXPORT_SYMBOL(clk_disable);

void check_clk_is_enable(int clkid)

{

if（clock_map_enabled[BIT_WORD(clkid)] & BIT_MASK(clkid））

{

printk("clk->id %d is enable/n",clkid);

}

}