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    SubjectRe: Complete support PC-9800 for 2.5.64-ac4 (11/11) SCSI
    On 16 Mar 2003, James Bottomley wrote:
    > On Sat, 2003-03-15 at 19:15, Osamu Tomita wrote:
    > > /* This is what the 3393 chip looks like to us */
    > > typedef struct {
    > > +#ifdef CONFIG_WD33C93_PIO
    > > + unsigned int SASR;
    > > + unsigned int SCMD;
    > > +#else
    > > volatile unsigned char *SASR;
    > > volatile unsigned char *SCMD;
    > > +#endif
    > > } wd33c93_regs;
    > >
    > This really doesn't look right. For non PIO (which is all drivers apart
    > from yours), they expect to dereference SASR to get the port number (as
    > an unsigned char). If you remove the dereference, don't they all break?

    On m68k and MIPS, we do not derefence SASR to get the port number, SASR _is_
    the MMIO pointer to the 8-bit SASR register. Hence you access the register by
    dereferencing the pointer.

    > Perhaps the better thing to do is to make your driver use an unsigned
    > int *, so the dereference works in all cases.

    Actually, it was my suggestion to remove the dereference for PIO accesses. In
    that case SASR contains the I/O port register.



    Geert Uytterhoeven -- There's lots of Linux beyond ia32 --

    In personal conversations with technical people, I call myself a hacker. But
    when I'm talking to journalists I just say "programmer" or something like that.
    -- Linus Torvalds

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