[Very RFC 37/46] powernv/pci: Use the PHB's rmap for pnv_ioda_to_pe()

[Oliver O'Halloran]

Rather than using the pdn->pe_number for a device as an index into the
IODA PE array we can use the reverse map. This maps the RID (i.e. bdfn)
to the PE number associated with it. Firmware maintains a copy of the
rmap which is used by the hardware for determining which PE to use
when handling a DMA so this gets us a bit closer to the model used
by the HW, which is comprensible by mortals, rather than... whatever
the hell is going on currently.

Signed-off-by: Oliver O'Halloran <oohall at gmail.com>
---
 arch/powerpc/platforms/powernv/pci-ioda.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 8525642b1256..d111a50fbe68 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -672,13 +672,9 @@ struct pnv_ioda_pe *__pnv_ioda_get_pe(struct pnv_phb *phb, u16 bdfn)
 struct pnv_ioda_pe *pnv_ioda_get_pe(struct pci_dev *dev)
 {
 	struct pnv_phb *phb = pci_bus_to_pnvhb(dev->bus);
-	struct pci_dn *pdn = pci_get_pdn(dev);
+	u16 bdfn = (dev->bus->number << 8) | dev->devfn;
 
-	if (!pdn)
-		return NULL;
-	if (pdn->pe_number == IODA_INVALID_PE)
-		return NULL;
-	return &phb->ioda.pe_array[pdn->pe_number];
+	return __pnv_ioda_get_pe(phb, bdfn);
 }
 
 static int pnv_ioda_set_one_peltv(struct pnv_phb *phb,
-- 
2.21.0