Messages in this thread | | | Subject | Re: [PATCH 3/5] MIPS: Loongson64: Enlarge IO_SPACE_LIMIT | From | Jiaxun Yang <> | Date | Mon, 20 Jul 2020 20:04:22 +0800 |
| |
在 2020/7/20 下午6:45, Arnd Bergmann 写道: > On Mon, Jul 20, 2020 at 9:44 AM Jiaxun Yang <jiaxun.yang@flygoat.com> wrote: >> It can be very big on LS7A PCH systems. >> >> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com> >> --- >> * On MIPS I/O ports are memory mapped, so we access them using normal >> diff --git a/arch/mips/include/asm/mach-loongson64/spaces.h b/arch/mips/include/asm/mach-loongson64/spaces.h >> index 3de0ac9d8829..b99b43854929 100644 >> --- a/arch/mips/include/asm/mach-loongson64/spaces.h >> +++ b/arch/mips/include/asm/mach-loongson64/spaces.h >> @@ -11,8 +11,7 @@ >> #define PCI_IOSIZE SZ_16M >> #define MAP_BASE (PCI_IOBASE + PCI_IOSIZE) >> >> -/* Reserved at the start of PCI_IOBASE for legacy drivers */ >> -#define MMIO_LOWER_RESERVED 0x10000 >> +#define IO_SPACE_LIMIT 0x00ffffff > Does this mean that firmware may already have assigned "high" I/O space > numbers for devices? I'm not sure how well device drivers can generally > deal with port numbers that don't fit into a 16-bit integer. Limited test shows most drivers can deal with that. But We'll aware the problem, thanks for the remind. > > Is it possible to run a 32-bit kernel on these machines? If yes, than > taking up 16MB of virtual addresses may also become a problem.
We've killed the ability of running 32-bit kernel on MACH_LOONGSON64.
> In practice, one should rarely need more than a few kb worth of > port numbers, unless you expect to see hundreds of legacy PCI > devices. I must blame stupid hardware design here. The LPC Controller (for ISA device) can eat up to 0x20000 IO BAR, and we can't resize it. Thus we have to enlarge the I/O Space.
Thanks!
- Jiaxun > > Arnd
| |