On Wed, 2022-05-04 at 12:33 +0200, Arnd Bergmann wrote: > On Wed, May 4, 2022 at 1:38 AM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > On Fri, Apr 29, 2022 at 03:50:41PM +0200, Niklas Schnelle wrote: > > > In a future patch HAS_IOPORT=n will result in inb()/outb() and friends > > > not being declared. PCMCIA devices are either LEGACY_PCI devices > > > which implies HAS_IOPORT or require HAS_IOPORT. > > > > > > Acked-by: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx> > > > Co-developed-by: Arnd Bergmann <arnd@xxxxxxxxxx> > > > Signed-off-by: Niklas Schnelle <schnelle@xxxxxxxxxxxxx> > > > --- > > > drivers/pcmcia/Kconfig | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/pcmcia/Kconfig b/drivers/pcmcia/Kconfig > > > index 2ce261cfff8e..32b5cd324c58 100644 > > > --- a/drivers/pcmcia/Kconfig > > > +++ b/drivers/pcmcia/Kconfig > > > @@ -5,7 +5,7 @@ > > > > > > menuconfig PCCARD > > > tristate "PCCard (PCMCIA/CardBus) support" > > > - depends on !UML > > > + depends on HAS_IOPORT > > > > I don't know much about PC Card. Is there a requirement that these > > devices must use I/O port space? If so, can you include a spec > > reference in the commit log? > > I think for PCMCIA devices, the dependency makes sense because > all device drivers for PCMCIA devices need I/O ports. > > For cardbus, we can go either way, I don't see any reference to > I/O ports in yenta_socket.c or the pccard core, so it would build > fine with or without I/O ports. > > > I do see the PC Card spec, r8.1, sec 5.5.4.2.2 says: > > > > All CardBus PC Card adapters must support either memory-mapped I/O > > or both memory-mapped I/O and I/O space. The selection will depend > > largely on the system architecture the adapter is intended to be > > used in. The requirement to also support memory-mapped I/O, if I/O > > space is supported, is driven by the potential emergence of > > memory-mapped I/O only cards. Supporting both modes may also > > position the adapter to be sold into multiple system architectures. > > > > which sounds like I/O space is optional. > > An earlier version of the patch series had a separate > CONFIG_LEGACY_PCI that required CONFIG_HAS_IOPORT > here, which I think made this clearer: > > Almost all architectures that support CONFIG_PCI also provide > HAS_IOPORT today (at least at compile time, if not at runtime), > with s390 as a notable exception. Any machines that have legacy > PCI device support will also have I/O ports because a lot of > legacy PCI cards used it, and any machine with a pc-card slot > should also support legacy PCI devices. > > If we get new architectures without I/O space in the future, they > would certainly not care about supporting old cardbus devices. > > Arnd I tested removing the HAS_IOPORT dependency on PCCARD thus ungating PCMCIA and CARDBUS. This then requires about 30 additional HAS_IOPORT dependencies to build my s390 allyesconfig. The only exceptions I found that depends on PCMCIA and isn't otherwise dependend on ISA or a specific platform are USB_SL811_CS and PCMCIA_RAYCS (Aviator/Raytheon 2.4GHz wireless). As for CARDBUS the only "depends on CARDBUS" is in drivers/net/ethernet/dec/tulip/Kconfig. Now I tested with allyesconfig which also sets CONFIG_TULIP_MMIO and with that the drivers there did compile. I guess one should then have "select TULIP_MMIO if !HAS_IOPORT" in the config NET_TULIP. So not sure, it seems unlikely we're going to see any new PCMCIA/CardBus device drivers added and that's a lot of churn for compile testing so few drivers but in theory it looks like it is possible to have non-I/O port PCMCIA/CardBus. Thanks, Niklas
