On Sunday 19 September 2010 16:07:02 Mike Rapoport wrote: > > diff --git a/arch/arm/mach-tegra/include/mach/io.h b/arch/arm/mach-tegra/include/mach/io.h > > index 35edfc3..d54e384 100644 > > --- a/arch/arm/mach-tegra/include/mach/io.h > > +++ b/arch/arm/mach-tegra/include/mach/io.h > > @@ -21,7 +21,8 @@ > > #ifndef __MACH_TEGRA_IO_H > > #define __MACH_TEGRA_IO_H > > > > -#define IO_SPACE_LIMIT 0xffffffff > > +/* Two 1MB windows */ > > +#define IO_SPACE_LIMIT (SZ_1M + SZ_1M - 1) > > This would limit ioport_resource to 2M, and request_resource(&ioport_resource, > &res) will fail because ioport_resource does not take into account that IO can > start somewhere else than at 0. Normally, the ioport_resource is limited to 65536 bytes in practice, because that's the most that many PCI cards decode. The only reason to let the I/O window start at something other than 0 is to leave space for legacy ISA devices, so typically the available range is between 0x1000 and 0xffff. I don't see that as a limitation here. > > /* On TEGRA, many peripherals are very closely packed in > > * two 256MB io windows (that actually only use about 64KB > > @@ -69,7 +70,7 @@ void tegra_iounmap(volatile void __iomem *addr); > > > > static inline void __iomem *__io(unsigned long addr) > > { > > - return (void __iomem *)addr; > > + return addr + tegra_pcie.regs + SZ_4M; > > I wish things were that simple :) > As far as I understand, the IO space should be mapped prior to use and __io > should return the virtual address. That's right. You already map all the PCI registers including the I/O port mapping at initialization time, but you must not attempt to access these during boot before that time. You should probably mask the size as above, which I forgot: static inline void __iomem *__io(unsigned long addr) { return (addr & IO_SPACE_LIMIT) + (tegra_pcie.regs + SZ_4M); } Hopefully it's clearer that way, and certainly safer in case someone passes the physical address of the I/O window into __io rather than the offset. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html