On Fri, Feb 10, 2012 at 9:20 AM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
> On Fri, Feb 10, 2012 at 8:55 AM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote:
> ...
>>>
>>> I mean, we can unify sysdata usuage, make them all most the same.
>>>
>>> and for some sysdata, already acting like host_bridge struct with
>>> domain, numa_node, and resources.
>>>
>>>> If you can show an example of what you mean, maybe it will help me understand.
>>>
>>> just looked the sys_data of different arch,
>>>
>>> looks like pci_sys_data for arm already include the io offset
>>>
>>> arch/arm/include/asm/mach/pci.h::
>>>
>>> struct pci_sys_data {
>>> #ifdef CONFIG_PCI_DOMAINS
>>> int domain;
>>> #endif
>>> struct list_head node;
>>> int busnr; /* primary bus number
>>> */
>>> u64 mem_offset; /* bus->cpu memory mapping
>>> offset */
>>> unsigned long io_offset; /* bus->cpu IO mapping offset
>>> */
>>> struct pci_bus *bus; /* PCI bus
>>> */
>>> struct list_head resources; /* root bus resources (apertures)
>>
>> Let me try again. Maybe your idea is that we should create something
>> like "struct pcibios_sysdata" and require every arch to define a
>> struct with that name. Every arch's struct would contain some members
>> such as "domain," "mem_offset," "io_offset," and "resources." These
>> would have standard names & types across all arches and would be
>> referenced by the PCI core. In addition, the struct could include
>> arch-specific data such as "acpi_handle," "iommu," etc.
>>
>> That way, the core could implement things like pci_domain_nr() and
>> pci_bus_to_resource() by using the data in struct pcibios_sysdata.
>> The current "void *sysdata" parameters to pci_scan_bus() and friends
>> would become "struct pcibios_sysdata *sysdata".
>>
>> I like the idea of unifying the sysdata struct name and changing from
>> a "void *" to something like "struct pcibios_sysdata *". That might
>> be worth doing.
>
> what i am mean:
> 1. make every arch to use same name for the struct, but could have
> different contents.
> struct pci_sys_data.
> 2. unify member field name, by changing name
> pci_first_busno ==> first_busno
> pci_last_busno ==> last_busno
> or adding
> first_busno
> last_busno
> 3. changing more filed like domain, node
> and io_offset, mem_offset
> ...
That's exactly what I said above, isn't it? (In the paragraph
starting "Let me try again.")
As I said, the reason I don't like that approach is that I don't want
a dozen copies of first_busno, last_busno, domain, node, io_offset,
mem_offset, etc. That information is not architecture-specific, so we
shouldn't keep it in an architecture-specific struct.
Bjorn
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