On Wed, Dec 09, 2020 at 12:08:51PM +0100, Enrico Weigelt, metux IT consult wrote: > Hello folks, > > > while trying to make some more drivers compile-test'able, i've > discovered some arch specific calls in here, eg.: > > > In file included from > /home/nekrad/src/apu2-dev/pkg/kernel.apu2.git/drivers/usb/host/ehci-spear.c:23: > /home/nekrad/src/apu2-dev/pkg/kernel.apu2.git/drivers/usb/host/ehci.h: > In function 'ehci_readl': > /home/nekrad/src/apu2-dev/pkg/kernel.apu2.git/drivers/usb/host/ehci.h:743:3: > error: implicit declaration of function 'readl_be'; did you mean > 'readsb'? [-Werror=implicit-function-declaration] > 743 | readl_be(regs) : > | ^~~~~~~~ > | readsb > /home/nekrad/src/apu2-dev/pkg/kernel.apu2.git/drivers/usb/host/ehci.h: > In function 'ehci_writel': > /home/nekrad/src/apu2-dev/pkg/kernel.apu2.git/drivers/usb/host/ehci.h:767:3: > error: implicit declaration of function 'writel_be'; did you mean > 'writesb'? [-Werror=implicit-function-declaration] > 767 | writel_be(val, regs) : > | ^~~~~~~~~ > | writesb > In file included from > /home/nekrad/src/apu2-dev/pkg/kernel.apu2.git/drivers/usb/host/ehci-hcd.c:97: > /home/nekrad/src/apu2-dev/pkg/kernel.apu2.git/drivers/usb/host/ehci.h: > In function 'ehci_readl': > /home/nekrad/src/apu2-dev/pkg/kernel.apu2.git/drivers/usb/host/ehci.h:743:3: > error: implicit declaration of function 'readl_be'; did you mean > 'readsb'? [-Werror=implicit-function-declaration] > 743 | readl_be(regs) : > | ^~~~~~~~ > | readsb > /home/nekrad/src/apu2-dev/pkg/kernel.apu2.git/drivers/usb/host/ehci.h: > In function 'ehci_writel': > /home/nekrad/src/apu2-dev/pkg/kernel.apu2.git/drivers/usb/host/ehci.h:767:3: > error: implicit declaration of function 'writel_be'; did you mean > 'writesb'? [-Werror=implicit-function-declaration] > 767 | writel_be(val, regs) : > | ^~~~~~~~~ > | writesb > > > It seems that only few archs (microblaze, ppc, sparc) define them. > > Also drivers/usb/host/ehci.h defines them, but only for one particular > arch/subarch. > > IIRC, these funcs are for accessing hw registers that are in BEs, so > BE cpus can do direct access, while LE cpus need to do a conversion. > > OTOH, we also have in_be32() / out_be32. They seem to do quite the same > thing, referenced much more often, but also just defined on a few archs. > > > I believe we should have generic functions, that all archs implement > (possibly doing automatic conversion, if necessary), which are used > by everybody else. > > What's your oppionion on that ?
It certainly seems reasonable. Another possibility, less stringent, is to require that definitions exist on all architectures that can have big-endian MMIO (or port-based IO). For example, any architecture which might select CONFIG_EHCI_BIG_ENDIAN_MMIO, as used in ehci.h. Otherwise we're left in the unfortunate position of having to provide definitions for these functions, but _only_ on architectures that don't already make their own definitions -- basically an impossible task. Alan Stern
