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 <yamah...@valinux.co.jp> 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 <zltjiang...@gmail.com>
>> ---
>> 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
