On Sat, Jul 19, 2014 at 11:11 AM, Sam Ravnborg <sam@xxxxxxxxxxxx> wrote: > On Sat, Jul 19, 2014 at 11:05:33AM +0200, Arnd Bergmann wrote: >> On Saturday 19 July 2014 10:41:52 Sam Ravnborg wrote: >> > > > >> > > > This set: >> > > > #define inb_p(addr) inb(addr) >> > > > #define inw_p(addr) inw(addr) >> > > > #define inl_p(addr) inl(addr) >> > > > #define outb_p(x, addr) outb((x), (addr)) >> > > > #define outw_p(x, addr) outw((x), (addr)) >> > > > #define outl_p(x, addr) outl((x), (addr)) >> > > > >> > > > Should have a comment that say they are deprecated. >> > > > Especially the "b" variants still have many users. >> > > >> > > Are they? I don't remember ever seeing a reason to deprecate >> > > them. We could perhaps enclose them in #ifdef CONFIG_ISA, but >> > > there may also be some drivers that use the same code for ISA >> > > and PCI, and it doesn't really hurt on PCI. >> > >> > It is my understanding that inl and inl_p are the same these days. >> > A quick grep indicate that only m68k define the >> > _p variant different from the other. >> > But I failed to find and description of the difference between the >> > two which is why I assumed they were identical and thus no need for both. >> >> I don't know why m68k needs it, it's really an x86-specific >> thing, see slow_down_io() in arch/x86/include/asm/io.h. > > I had missed the x86 versions when grepping. > Hmm, and with the macro tricks they play in asm/io.h this > file is not at all grep friendly. > > So xxx_p is for pause (or something like that). > This also matches that m68k do some tricks with delay() in the _p variants. > Thanks for the explanation. m68k's isa_delay() uses the same approach as x86's slow_down_io(), but only for Q40/Q60, which has a "real" ISA bus that accepts legacy ISA expansion cards (http://www.q40.de/). Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx 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 -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
