Kenji Kaneshige wrote:
> Yinghai Lu wrote:
>> Yinghai Lu wrote:
>>> Kenji Kaneshige wrote:
>>>> I understand you need to touch I/O base/limit and Mem base/limit. But
>>>> I don't understand why you also need to update bridge's BARs. Could
>>>> you please explain a little more about it?
>>>>
>>>> Just in case, my terminology "bridge's BARs" is Base Address Register
>>>> 0 (offset 0x10) and Base Address Register 1 (offset 0x14) in the
>>>> (type 1) configuration space header of the bridge.
>>> i mean 0x1c, 0x20, 0x28
>>>
>>> did not notice that bridge device's 0x10, 0x14 are used...
>>> if port service need to use 0x10, 0x14, and the device is enabled, we
>>> should touch 0x10, and 0x14.
>>
>> after check the code, if
>> pci_bridge_assign_resources ==> pdev_assign_resources_sorted ==>
>> pdev_sort_resources
>>
>> will not touch 0x10 and 0x14, if those resource is claimed by port
>> service.
>>
>> /* Sort resources by alignment */
>> void pdev_sort_resources(struct pci_dev *dev, struct resource_list *head)
>> { int i;
>> for (i = 0; i < PCI_NUM_RESOURCES; i++) {
>> struct resource *r;
>> struct resource_list *list, *tmp;
>> resource_size_t r_align;
>> r = &dev->resource[i];
>> if (r->flags &
>> IORESOURCE_PCI_FIXED)
>> continue;
>> if (!(r->flags) || r->parent)
>> continue;
>>
>> r->parent != NULL, will make it skip those two.
>>
>> So -v3 should be safe.
>>
>
> Thank you for the clarification.
>
> But I still don't understand the whole picture of your set of
> changes. Let me ask some questions.
>
> In my understanding of your set of changes, if there is a PCIe
> switch with some hot-plug slots and all of those slots are empty,
> I/O and Memory resources assigned by BIOS are all released at
> the boot time. For example, suppose the following case.
>
> bridge(A)
> |
> -----------------------
> | |
> bridge(B) bridge(C)
> | |
> slot(1) slot(2)
> (empty) (empty)
>
> bridge(A): P2P bridge for switch upstream port
> bridge(B): P2P bridge for switch downstream port
> bridge(C): P2P bridge for switch downstream port
>
> In the above example, I/O and Mem resource assigned to bridge(A),
> bridge(B) and bridge(C) are all released at the boot time. Correct?
>
> Then, when a adapter card is hot-added to slot(1), I/O and Mem
> resources enough for enabling the hot-added adapter card is assigned
> to bridge(A), bridge(B) and the adapter card. Correct?
>
> Then, when an another adpater card is hot-added to slot(2), we
> need to assign enough resource to bridge(C) and the new card.
> But bridge(A) doesn't have enough resource for bridge(C) and
> the new card. In addition, all bridge(A) and bridge(B) and the
> adapter card on slot(1) are already working. How do you assign
> resource to bridge(C) and the card on slot(2)?
>
thanks, will update the patches to only handle leaf bridge, and don't touch min_size etc.
YH
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