Re: Being more anal about iospace accesses..

From: linux
Date: Wed Sep 15 2004 - 13:28:55 EST


> Nice.
>
> But it still leaves me confused. Before I had this code:
>
> struct regs {
> uint32_t status;
> ...
> }
>
> ...
>
> struct regs *regs = ioremap(...);
> uint32_t status = regs->status;
> ...
>
> So now I should do it like this:
>
> #define REG_STATUS 0
>
> ...
>
> void __iomem *regs = ioremap(...);
> uint32_t status = readl(regs + REG_STATUS);
> ...
>
> But wait, that only works when long is 32bit wide. Plus I could be
> stupid enough and "#define REG_STATUS 64" while the register space is
> just 64 bytes long. It solves the confusion about address spaces,
> agreed, but overall I'm more confused now. Hope it's just temporary.

No, you should do:

struct regs {
uint32_t status;
...
}

...

struct regs __iomem *regs = ioremap(...);
uint32_t status = ioread32(&regs->status);
-
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