Re: [PATCH V19 07/13] MIPS: Loongson 3: Add IRQ init and dispatch support

[Ralf Baechle <ralf@linux-mips.org>]

On Sun, Feb 16, 2014 at 04:01:24PM +0800, Huacai Chen wrote:

> +#define LOONGSON_HT1_INT_VECTOR_BASE	(LOONGSON_HT1_CFG_BASE + 0x80)
> +#define LOONGSON_HT1_INT_EN_BASE	(LOONGSON_HT1_CFG_BASE + 0xa0)
> +#define LOONGSON_HT1_INT_VECTOR(n)	\
> +		LOONGSON3_REG32(LOONGSON_HT1_INT_VECTOR_BASE, 4 * n)
> +#define LOONGSON_HT1_INTN_EN(n)		\
> +		LOONGSON3_REG32(LOONGSON_HT1_INT_EN_BASE, 4 * n)

Doing math on macro arguments without parenthesis is dangerous,  please
use (n) instead.

> +
> +#define LOONGSON_INT_ROUTER_OFFSET	0x1400
> +#define LOONGSON_INT_ROUTER_INTEN	\
> +	  LOONGSON3_REG32(LOONGSON3_REG_BASE, LOONGSON_INT_ROUTER_OFFSET + 0x24)
> +#define LOONGSON_INT_ROUTER_INTENSET	\
> +	  LOONGSON3_REG32(LOONGSON3_REG_BASE, LOONGSON_INT_ROUTER_OFFSET + 0x28)
> +#define LOONGSON_INT_ROUTER_INTENCLR	\
> +	  LOONGSON3_REG32(LOONGSON3_REG_BASE, LOONGSON_INT_ROUTER_OFFSET + 0x2c)
> +#define LOONGSON_INT_ROUTER_ENTRY(n)	\
> +	  LOONGSON3_REG8(LOONGSON3_REG_BASE, LOONGSON_INT_ROUTER_OFFSET + n)
> +#define LOONGSON_INT_ROUTER_LPC		LOONGSON_INT_ROUTER_ENTRY(0x0a)
> +#define LOONGSON_INT_ROUTER_HT1(n)	LOONGSON_INT_ROUTER_ENTRY(n + 0x18)

These two also.

> +static void ht_irqdispatch(void)
> +{
> +	unsigned int i, irq;
> +	unsigned int ht_irq[] = {1, 3, 4, 5, 6, 7, 8, 12, 14, 15};
> +
> +	irq = LOONGSON_HT1_INT_VECTOR(0);
> +	LOONGSON_HT1_INT_VECTOR(0) = irq; /* Acknowledge the IRQs */
> +
> +	for (i = 0; i < ARRAY_SIZE(ht_irq); i++) {
> +		if (irq & (0x1 << ht_irq[i]))
> +			do_IRQ(ht_irq[i]);
> +	}
> +}

Ouch.

Initializing an array like this in C will generate code which at runtime
initializes the ht_irq[] array each time ht_irqdispatch is invoked
and slowing this function to a crawl.

You want to make either move the definition of this array out of the
function body or make it "static const unsigned int ht_irq[] ..." to
avoid this.

  Ralf