Re: [Qemu-devel] Re: [RFC][PATCH] PCI: fix pci_to_cpu_addr() issue

[Isaku Yamahata]

Thank you the pointer. I found the followings.
https://groups.google.com/group/archlinux-for-loongson/web/loongson
https://groups.google.com/group/archlinux-for-loongson/web/bonito64-spec.pdf
Am I referring to a correct spec?

According to it,
[0x00000000,  0x10000000) RAM
[0x10000000,  0x14000000) PCI_Lo0
[0x14000000,  0x18000000) PCI_Lo1
[0x18000000,  0x1c000000) PCI_Lo2
[0x20000000,  0x80000000) PCI_1.5
[0x80000000, 0x100000000) PCI_2         

[0x00000000, 0x0c000000) in physical address is RAM, so I don't understand PMON 
uses
the area. I may be misunderstanding something.
Can you elaborate please?

PCI_Lo[123] is interesting. The base address can be programmed independently.
Such operation isn't assumed by qemu.


On Wed, Jun 30, 2010 at 10:05:55PM +0800, chen huacai wrote:
> Maybe this is what you want, please look at Page 10.
> http://people.openrays.org/~comcat/godson/doc/godson2e.north.bridge.manual.pdf
> But it is written in Chinese, I'm sorry that I also don't have an
> English version.
> 
> 
> On Wed, Jun 30, 2010 at 9:38 PM, Isaku Yamahata <address@hidden> wrote:
> > Can you elaborate on how pci bus is mapped into local bus?
> > Is there specification publicly available? Google didn't tell me.
> >
> >
> > On Wed, Jun 30, 2010 at 06:39:53PM +0800, Huacai Chen wrote:
> >> It seems like software may both use CPU address or PCI address to access a 
> >> PCI
> >> device. For example, Bonito north bridge map PCI memory space at 
> >> 0x10000000 ~
> >> 0x1C000000. PMON code use 0x00000000 ~ 0x0C000000, but Linux kernel code 
> >> use
> >> 0x10000000 ~ 0x1C000000 to access devices. If set pci_mem_base to 0, PMON 
> >> can't
> >> work, but if set pci_mem_base to 0x10000000, Linux can't access PCI. So I 
> >> make
> >> this patch to make both cases works.
> >>
> >> However, I don't know whether the modification will break other archs, so
> >> request for comments here.
> >>
> >> Signed-off-by: Huacai Chen <address@hidden>
> >> ---
> >> ??hw/pci.c | ?? ??2 +-
> >> ??1 files changed, 1 insertions(+), 1 deletions(-)
> >>
> >> diff --git a/hw/pci.c b/hw/pci.c
> >> index 7787005..50e3572 100644
> >> --- a/hw/pci.c
> >> +++ b/hw/pci.c
> >> @@ -672,7 +672,7 @@ PCIDevice *pci_register_device(PCIBus *bus, const char 
> >> *name,
> >> ??static target_phys_addr_t pci_to_cpu_addr(PCIBus *bus,
> >> ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? 
> >> ??target_phys_addr_t addr)
> >> ??{
> >> - ?? ??return addr + bus->mem_base;
> >> + ?? ??return addr | bus->mem_base;
> >> ??}
> >>
> >> ??static void pci_unregister_io_regions(PCIDevice *pci_dev)
> >> --
> >> 1.7.0.4
> >>
> >
> > --
> > yamahata
> >
> 
> 
> 
> -- 
> Huacai Chen
> 

-- 
yamahata