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    SubjectRe: unsigned long ioremap()?
    At 3:18 AM -0400 2001-05-03, Jeff Garzik wrote:
    >"David S. Miller" wrote:
    >> There is a school of thought which believes that:
    > > struct xdev_regs {
    >> u32 reg1;
    >> u32 reg2;
    >> };
    > >
    >> val = readl(&regs->reg2);
    >> is cleaner than:
    >> #define REG1 0x00
    >> #define REG2 0x04
    >> val = readl(regs + REG2);
    >> I'm personally ambivalent and believe that both cases should be allowed.
    >Agreed... Tangent a bit, I wanted to plug using macros which IMHO make
    >code even more readable:
    > val = RTL_R32(REG2);
    > RTL_W32(REG2, val);
    >Since these are driver-private, if you are only dealing with one chip
    >you could even shorten things to "R32" and "W32", if that doesn't offend
    >any sensibilities :)

    With a little arithmetic behind the scenes and a NULL pointer to the
    struct xdev, you could have:

    struct xdev_regs {
    u32 reg1;
    u32 reg2;
    } *xdr = 0;

    #define RTL_R32(REG) readl(cookie+(unsigned long)(&xdr->REG))

    cookie = ioremap(blah, blah);

    val = RTL_R32(reg2);

    ...and have the benefits of the R32 macro as well as the use of
    structure members.
    /Jonathan Lundell.
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