On 11/12/2015 03:55 PM, Gavin Shan wrote:
On Thu, Nov 12, 2015 at 02:30:27PM +1100, Daniel Axtens wrote:
Hi Gavin,
Sorry to have taken so long to resume these reviews!
Thanks for your review, Daniel!
Currently, the IO and M32 segments are mapped to the corresponding
PE based on the windows of the parent bridge of PE's primary bus.
It's not going to work when the windows of root port or upstream
port of the PCIe switch behind root port are extended to PHB's
aperatuses in order to support hotplug in subsequent patch.
I'm not _entirely_ sure I understand this.
I *think* you mean PHB's apertures (i.e. s/aperatuses/apertures/)?
I'll fix the typo in next revision.
This fixes the issue by mapping IO and M32 segments based on the
resources of the PCI devices included in the PE, instead of the
windows of the parent bridge of the PE's primary bus.
This solution seems to make a lot of sense, but I don't have a very good
understanding of PCI yet: why was it done that way and not this way
originally? Looking at the code, it looks like the old way was simple
but didn't support SR-IOV?
It's not related to SRIOV. Originally, the IO or M32 segments are mapped
according to the bridge's windows.
Sorry, I do not understand what this means...
The bridge windows on root port or the
upstream port of the switch behind that will be extended to PHB's apertures.
What does "extended" mean here and why would the windows be extended anyway?
If we still use bridge's windows, all IO and M32 resources are mapped/assigned
to the PE corresponding to PCI bus#1 or PCI bus#2. That's not correct any more.
So the correct way is to do the mapping based on IO or M32 BARs of the devices
included in the PE.
In this patch I see quite a lot of code movements and I fail to spot the
actual change here...
It used to be a single loop:
pci_bus_for_each_resource(pe->pbus, res, i) {
/* do stuff for each @res */
}
and now it is 2 loops inside another loop:
list_for_each_entry(pdev, &pe->pbus->devices, bus_list) {
for (i = 0; i <= PCI_ROM_RESOURCE; i++) {
res = &pdev->resource[i];
/* do stuff for each @res */
}
for (i = 0; i <= PCI_BRIDGE_RESOURCE_NUM; i++) {
res = &pdev->resource[PCI_BRIDGE_RESOURCES + i];
/* do stuff for each @res */
}
}
Is that correct? If yes, why is not the patch as simple as this? If no,
what did I miss?
There are a few comments inline as well.
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 553d3f3..4ab93f8 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -2741,71 +2741,90 @@ truncate_iov:
}
#endif /* CONFIG_PCI_IOV */
-/*
- * This function is supposed to be called on basis of PE from top
- * to bottom style. So the the I/O or MMIO segment assigned to
- * parent PE could be overrided by its child PEs if necessary.
- */
-static void pnv_ioda_setup_pe_seg(struct pci_controller *hose,
- struct pnv_ioda_pe *pe)
+static int pnv_ioda_setup_one_res(struct pnv_ioda_pe *pe,
+ struct resource *res)
{
- struct pnv_phb *phb = hose->private_data;
+ struct pnv_phb *phb = pe->phb;
struct pci_bus_region region;
- struct resource *res;
- unsigned int segsize;
- int *segmap, index, i;
+ unsigned int index, segsize;
+ int *segmap;
uint16_t win;
int64_t rc;
s/int64_t/s64/;
I think we might also want to change the uint16_t as well.
As I explained before, I changed it from s64 to int64_t and I won't change it
back since both of them are fine. Same situation to uint16 here. If we really
want to clean it all at once, I can do that later, but not in this patchset.
- /*
- * NOTE: We only care PCI bus based PE for now. For PCI
- * device based PE, for example SRIOV sensitive VF should
- * be figured out later.
- */
- BUG_ON(!(pe->flags & (PNV_IODA_PE_BUS | PNV_IODA_PE_BUS_ALL)));
+ if (!res->parent || !res->flags || res->start > res->end)
+ return 0;
- pci_bus_for_each_resource(pe->pbus, res, i) {
- if (!res || !res->flags ||
- res->start > res->end)
- continue;
+ if (res->flags & IORESOURCE_IO) {
+ region.start = res->start - phb->ioda.io_pci_base;
+ region.end = res->end - phb->ioda.io_pci_base;
+ segsize = phb->ioda.io_segsize;
+ segmap = phb->ioda.io_segmap;
+ win = OPAL_IO_WINDOW_TYPE;
+ } else if ((res->flags & IORESOURCE_MEM) &&
+ !pnv_pci_is_mem_pref_64(res->flags)) {
+ region.start = res->start -
+ phb->hose->mem_offset[0] -
+ phb->ioda.m32_pci_base;
+ region.end = res->end -
+ phb->hose->mem_offset[0] -
+ phb->ioda.m32_pci_base;
+ segsize = phb->ioda.m32_segsize;
+ segmap = phb->ioda.m32_segmap;
+ win = OPAL_M32_WINDOW_TYPE;
This code asks for a helper function
pnv_ioda_do_setup_one_res(start, end, segsize, segmap, win)
and then you won't need many local variables (region, segsize, segmap, win) ;)
--
Alexey
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