Thomas,
Sorry again for the mistake on my part. Let me try to address some other
concerns you have below.
On 09/22/2014 04:08 PM, Thomas Gleixner wrote:
On Sat, 20 Sep 2014, suravee.suthikulpanit@xxxxxxx wrote:
From: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
This patch implelments the ARM64 version of arch_setup_msi_irqs(),
which does not return 1 for when PCI_CAP_ID_MSI and nvec > 1.
I can see that myself. What your changelog is missing is the reason
WHY you think that copying that code from drivers/pci/msi.c and
removing the "PCI_CAP_ID_MSI and nvec > 1" has any value.
[Suravee] This is mainly be cause the weak version of
arch_setup_msi_irqs() in the drivers/pci/msi.c doesn't support
multi-MSI. Sorry for not being clear in the commit message.
And that new function "arm64_setup_msi_irqs" is declared in which
header file exactly?
[Suravee] This was supposed to be arch_setup_msi_irqs(). My bad. I'm
fixing this in the next version.
......
+ *
+ * Note:
+ * Current implementation assumes that all interrupt controller used in
+ * ARM64 architecture _MUST_ supports multi-MSI.
Great assumption....
[Suravee] So, Marc and I have discussed in the past that at this point,
we are not seeing the case that there will be interrupt or
MSI-controller that will not support multi-MSI. If you think this
should not be the case, would you please share your thought.
......
At least you are consistent on the useless side of affairs:
+{
+ struct msi_desc *entry;
+ int ret;
+
+ list_for_each_entry(entry, &dev->msi_list, list) {
+ ret = arch_setup_msi_irq(dev, entry);
Anyone who has the slightest idea how multi-MSI works will know that
this CANNOT work at all, but that's none of my business.
[Suravee] I noticed that in the x86 version, there is a callback that
each MSI controller need to register for handling the multi-MSI stuff.
In gicv2m_setup_msi_irq(), there is logic which handles the setup for
multi-MSI and MSIx separately. In case of multi-MSI, the vectors are
allocated on the first call to arch_setup_msi_irq(). Here, Marc and I
are trying to simplify the arch-specific code so that each GIC
controller (V2m and V3) would not need to implement and register the
callbacks separately for handling multi-MSI.
The thing that is broken here is the error handling where the
arch_setup_msi_irqs() is supposed to return the number of available MSI
vectors. It would fail to do so because the arch_setup_msi_irq() would
not return positive value. We should be able to fix this by
re-implementing the arch_setup_msi_irq() and arch_setup_msi_irqs() to
allow returning of positive values.
Please let me know what you think. I am open for suggestions :)
Thanks,
Suravee
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