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| pci_assign_unassigned_bus_resources(b)
void pci_assign_unassigned_bus_resources(struct pci_bus *bus)
{
struct pci_dev *dev;
LIST_HEAD(add_list); /* list of resources that
want additional resources */
down_read(&pci_bus_sem);
list_for_each_entry(dev, &bus->devices, bus_list)
if (pci_is_bridge(dev) && pci_has_subordinate(dev))
/* 这里传入的参数是bus 1对应的pci_bus */
__pci_bus_size_bridges(dev->subordinate,
&add_list);
up_read(&pci_bus_sem);
/* 配置各个桥和设备的BAR，配置桥的MEM，I/O，prefetch MEM base/limit */
__pci_bus_assign_resources(bus, &add_list, NULL);
BUG_ON(!list_empty(&add_list));
}
__pci_bus_size_bridges(struct pci_bus *bus, struct list_head *realloc_head)
...
/* 在当前的连接状态下，list中的代码不会执行。下面的代码层层递归，直到
* 最底层设备的上的pci_bus，这时最底层设备是没有下一级的pci_bus的。
* 所以，继续执行后面的代码。
*/
-->list_for_each_entry(dev, &bus->devices, bus_list) {
...
case PCI_CLASS_BRIDGE_PCI:
default:
__pci_bus_size_bridges(b, realloc_head);
break;
}
...
/* 当前pci_bus的桥对应的pci_dev, 这里应该是host */
-->switch (bus->self->class >> 8) {
...
case PCI_CLASS_BRIDGE_PCI:
/* 会执行这里 */
pci_bridge_check_ranges(bus);
...
default:
/* 这个函数改变了pci_bus->resource[]中的值。start对齐4K，size是该bus下
* 所有I/O空间的总和。但是似乎realloc_head
* list似乎没有node添加上去
*/
pbus_size_io(bus, realloc_head ? 0 : additional_io_size,
additional_io_size, realloc_head);
/*
* If there's a 64-bit prefetchable MMIO window, compute
* the size required to put all 64-bit prefetchable
* resources in it.
*/
b_res = &bus->self->resource[PCI_BRIDGE_RESOURCES];
mask = IORESOURCE_MEM;
prefmask = IORESOURCE_MEM | IORESOURCE_PREFETCH;
if (b_res[2].flags & IORESOURCE_MEM_64) {
prefmask |= IORESOURCE_MEM_64;
ret = pbus_size_mem(bus, prefmask, prefmask,
prefmask, prefmask,
realloc_head ? 0 : additional_mem_size,
additional_mem_size, realloc_head);
/*
* If successful, all non-prefetchable resources
* and any 32-bit prefetchable resources will go in
* the non-prefetchable window.
*/
if (ret == 0) {
mask = prefmask;
type2 = prefmask & ~IORESOURCE_MEM_64;
type3 = prefmask & ~IORESOURCE_PREFETCH;
}
}
/*
* If there is no 64-bit prefetchable window, compute the
* size required to put all prefetchable resources in the
* 32-bit prefetchable window (if there is one).
*/
if (!type2) {
prefmask &= ~IORESOURCE_MEM_64;
ret = pbus_size_mem(bus, prefmask, prefmask,
prefmask, prefmask,
realloc_head ? 0 : additional_mem_size,
additional_mem_size, realloc_head);
/*
* If successful, only non-prefetchable resources
* will go in the non-prefetchable window.
*/
if (ret == 0)
mask = prefmask;
else
additional_mem_size += additional_mem_size;
type2 = type3 = IORESOURCE_MEM;
}
/*
* Compute the size required to put everything else in the
* non-prefetchable window. This includes:
*
* - all non-prefetchable resources
* - 32-bit prefetchable resources if there's a 64-bit
* prefetchable window or no prefetchable window at all
* - 64-bit prefetchable resources if there's no
* prefetchable window at all
*
* Note that the strategy in __pci_assign_resource() must
* match that used here. Specifically, we cannot put a
* 32-bit prefetchable resource in a 64-bit prefetchable
* window.
*/
pbus_size_mem(bus, mask, IORESOURCE_MEM, type2, type3,
realloc_head ? 0 : additional_mem_size,
additional_mem_size, realloc_head);
break;
}
}
__pci_bus_assign_resources(bus, &add_list, NULL)
/* bus:0, 会对该bus上的所有device分别调用__dev_sort_resource
* 然后统一调用一个__assign_resources_sorted()。之后程序进入
* 下面的list中，又会嵌套进入__pci_bus_assign_resources, 这时
* bus:1。重复上面的过程。在bus:1是__pci_bus_assign_resources
* 在处理处理完pbus_assign_resources_sorted后不回往下执行,返回
* 上层。这时bus:0, 进入pci_setup_bridge执行。
* 其中，会在pbus_assign_resources_sorted中配置BAR，在
* __pci_setup_bridge中配mem, I/O, prefetch mem的base/limit
*/
--> pbus_assign_resources_sorted(bus, realloc_head, fail_head);
--> list_for_each_entry(dev, &bus->devices, bus_list)
--> __pci_bus_assign_resources(b, realloc_head, fail_head);
--> switch (dev->class >> 8)
case PCI_CLASS_BRIDGE_PCI:
--> pci_setup_bridge(b);
static void pbus_assign_resources_sorted()
--> LIST_HEAD(head);
--> list_for_each_entry(dev, &bus->devices, bus_list)
__dev_sort_resources(dev, &head);
/* 把pci_dev中的resource[]从大到小排序, 存入链表head中 */
--> pdev_sort_resources(dev, head);
--> __assign_resources_sorted(&head, realloc_head, fail_head);
/* 因为realloc_head为空链表，所以直接到requested_and_reassign */
--> if (!realloc_head || list_empty(realloc_head))
goto requested_and_reassign;
...
requested_and_reassign:
--> assign_requested_resources_sorted(head, fail_head);
/* dev_res(pci_dev_resource)存储一个device中一个配置空间
* 的资源(一个设备可有多个mem或I/O配置空间)
*/
--> list_for_each_entry(dev_res, head, list)
--> resource_size(res) &&
pci_assign_resource(dev_res->dev, idx)
--> _pci_assign_resource(dev, resno, size, align);
--> pci_update_resource(dev, resno);
--> reassign_resources_sorted(realloc_head, head);
|
