On Thu, Oct 07, 2010 at 08:24:58PM +0900, Jongsun Han wrote:
> +static unsigned int s5pv310_irq_split(unsigned int number)
> +{
> + u32 ret;
> + u32 test = number;
> +
> + ret = do_div(test, IRQ_EINT_BASE);
> +
> + do_div(ret, 8);
> +
> + return ret;
> +}
> +
> +static unsigned int s5pv310_irq_to_bit(unsigned int irq)
> +{
> + u32 ret;
> + u32 tmp;
> +
> + tmp = do_div(irq, IRQ_EINT_BASE);
> +
> + ret = do_div(tmp, 8);
> +
> + return 1 << ret;
> +}
These are a silly use of do_div(). do_div() is for 64-bit modulus/division,
not 32-bit. If you want to do 32-bit, then use the normal C maths.
What the above equates to is:
tmp = irq % IRQ_EINT_BASE;
ret = tmp % 8;
However, I don't think you want to do modulus operations there at all.
What I think you actually want is:
return 1 << ((irq - IRQ_EINT_BASE) % 7);
noting that the compiler will optimize this to a subtract and bit-wise and
operation.
For the former:
return ((irq - IRQ_EINT_BASE) / 8);
noting that the compiler will optimize this to a subtract and shift.
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