diff mbox

[kernel,2/3] pci-ioda: Set PCI_BUS_FLAGS_MSI_REMAP for IODA host bridge

Message ID 20170615054845.8428-3-aik@ozlabs.ru (mailing list archive)
State New, archived
Delegated to: Bjorn Helgaas
Headers show

Commit Message

Alexey Kardashevskiy June 15, 2017, 5:48 a.m. UTC 
From: Yongji Xie <elohimes@gmail.com>

Any IODA host bridge have the capability of IRQ remapping.
So we set PCI_BUS_FLAGS_MSI_REMAP when this kind of host birdge
is detected.

Signed-off-by: Yongji Xie <xyjxie@linux.vnet.ibm.com>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/platforms/powernv/pci-ioda.c | 8 ++++++++
 1 file changed, 8 insertions(+)

Comments

Michael Ellerman June 15, 2017, 9:25 a.m. UTC | #1 
Alexey Kardashevskiy <aik@ozlabs.ru> writes:

> From: Yongji Xie <elohimes@gmail.com>
>
> Any IODA host bridge have the capability of IRQ remapping.
> So we set PCI_BUS_FLAGS_MSI_REMAP when this kind of host birdge
> is detected.

Where's the code that actually enforces this property?

It would be good to have a comment in pnv_pci_ioda_root_bridge_prepare()
(probably), pointing to that code, so that we can remember the
relationship between the two.

cheers
Benjamin Herrenschmidt June 15, 2017, 10:56 a.m. UTC | #2 
On Thu, 2017-06-15 at 19:25 +1000, Michael Ellerman wrote:
> Alexey Kardashevskiy <aik@ozlabs.ru> writes:
> 
> > From: Yongji Xie <elohimes@gmail.com>
> > 
> > Any IODA host bridge have the capability of IRQ remapping.
> > So we set PCI_BUS_FLAGS_MSI_REMAP when this kind of host birdge
> > is detected.
> 
> Where's the code that actually enforces this property?
> 
> It would be good to have a comment in pnv_pci_ioda_root_bridge_prepare()
> (probably), pointing to that code, so that we can remember the
> relationship between the two.

Actually it's not so much remapping as:

 - The bridge can enforce that the interrupt is allowed for a given
partition

 - Because the interrupts are handled via the hypervisor, the latter
can do the remapping.

But the effect is the same, so yes we want the flag. On P9 with XIVE
exploitation we also have HW remapping on top.

Cheers,
Ben.
diff mbox

Patch

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 283caf1070c9..b6bda1918273 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -3177,6 +3177,12 @@  static void pnv_pci_ioda_fixup(void)
 #endif
 }
 
+int pnv_pci_ioda_root_bridge_prepare(struct pci_host_bridge *bridge)
+{
+	bridge->bus->bus_flags |= PCI_BUS_FLAGS_MSI_REMAP;
+	return 0;
+}
+
 /*
  * Returns the alignment for I/O or memory windows for P2P
  * bridges. That actually depends on how PEs are segmented.
@@ -3861,6 +3867,8 @@  static void __init pnv_pci_init_ioda_phb(struct device_node *np,
 	 */
 	ppc_md.pcibios_fixup = pnv_pci_ioda_fixup;
 
+	ppc_md.pcibios_root_bridge_prepare = pnv_pci_ioda_root_bridge_prepare;
+
 	if (phb->type == PNV_PHB_NPU) {
 		hose->controller_ops = pnv_npu_ioda_controller_ops;
 	} else {