Hi Corey Many Thanks for your comments
[...] > > #define IO_SPACE_LIMIT 0xffff > > #endif > > > > +#include <linux/logic_pio.h> > > This whole thing would be a lot simpler if you had: > > #ifdef CONFIG_INDIRECT_PIO > #define inb logic_inb > #define outb logic outb > . > . > #endif /* CONFIG_INDIRECT_PIO */ > > and let the "ifndef XXX" below handle not enabling the standard code. > You could even put that in logic_pio.h to avoid polluting io.h. Agreed. I'll move it into "logic_pio.h" > > You might have to add "#ifndef inb", etc. above, but I still think it > would > be better. Yes agreed also on adding the "#ifndef ***" around each function re-definition in logic_pio.h This will be fixed in v11 > > I'm not sure if this wouldn't be better done in arm64/include/asm/io.h, > though. > A specific machine may want to only do this in ranges, for instance. No I don’t think so...this io functions re-0definition has nothing to do with ARM architecture and I think it is better to keep everything in logic_pio.h including the file from "include/asm-generic/io.h" Cheers Gab > > -corey [...] > > --- a/lib/Kconfig > > +++ b/lib/Kconfig > > @@ -59,6 +59,32 @@ config ARCH_USE_CMPXCHG_LOCKREF > > config ARCH_HAS_FAST_MULTIPLIER > > bool > > > > +config LOGIC_PIO > > + bool "Generic logical I/O management" > > + def_bool y if PCI && !X86 && !IA64 && !POWERPC > > + help > > + For some architectures, there are no IO space. To support the > > + accesses to legacy I/O devices on those architectures, kernel > > + implemented the memory mapped I/O mechanism based on bridge bus > > + supports. But for some buses which do not support MMIO, the > > + peripherals there should be accessed with device-specific way. > > + To abstract those different I/O accesses into unified I/O > accessors, > > + this option provide a generic I/O space management way after > mapping > > + the device I/O to system logical/fake I/O and help to hide all > the > > + hardware detail. > > + > > +config INDIRECT_PIO > > + bool "Access I/O in non-MMIO mode" if LOGIC_PIO > > + help > > + On some platforms where no separate I/O space exist, there are > I/O > > + hosts which can not be accessed in MMIO mode. Based on > LOGIC_PIO > > + mechanism, the host-local I/O resource can be mapped into > system > > + logic PIO space shared with MMIO hosts, such as PCI/PCIE, then > system > > + can access the I/O devices with the mapped logic PIO through > I/O > > + accessors. > > + This way has a little I/O performance cost. Please make sure > your > > + devices really need this configure item enabled. > > + > > If this is always available on the hisilicon chips, I think you would > want to just always > enable this on those chips. In patch 6/9 we have +config HISILICON_LPC + bool "Support for ISA I/O space on Hisilicon Hip0X" + depends on (ARM64 && (ARCH_HISI || COMPILE_TEST)) + select LOGIC_PIO + select INDIRECT_PIO So the LPC host controller driver is selecting INDIRECT_PIO... > > -corey > Cheers Gab
