[Very RFC 02/46] powernv/pci: Add helper to find ioda_pe from BDFN

[Oliver O'Halloran]

Linux has a look-up table for mapping BDFNs to PEs which is updated when we
call into OPAL to update the PHB's internally BDFN<->PE mapping. We can use
this table to the PE for a device without needing to use the cached value
inside the pci_dn.

We'd like to get rid of pci_dn eventually so this patch adds adds a helper
to find the ioda_pe of a BDFN based on the table. This is different to the
existing helper which takes a pci_dev directly because there are some
contexts (e.g. EEH recovery) where we need to check for an existing PE
assignment when no corresponding pci_dev exists.

Signed-off-by: Oliver O'Halloran <oohall at gmail.com>
---
 arch/powerpc/platforms/powernv/pci-ioda.c | 10 ++++++++++
 arch/powerpc/platforms/powernv/pci.h      |  1 +
 2 files changed, 11 insertions(+)

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index fdacf98555e9..65b5b121ebad 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -660,6 +660,16 @@ static int pnv_ioda_get_pe_state(struct pnv_phb *phb, int pe_no)
 	return state;
 }
 
+struct pnv_ioda_pe *__pnv_ioda_get_pe(struct pnv_phb *phb, u16 bdfn)
+{
+	int pe_number = phb->ioda.pe_rmap[bdfn];
+
+	if (pe_number == IODA_INVALID_PE)
+		return NULL;
+
+	return &phb->ioda.pe_array[pe_number];
+}
+
 struct pnv_ioda_pe *pnv_ioda_get_pe(struct pci_dev *dev)
 {
 	struct pci_controller *hose = pci_bus_to_host(dev->bus);
diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
index f914f0b14e4e..01a01739c03e 100644
--- a/arch/powerpc/platforms/powernv/pci.h
+++ b/arch/powerpc/platforms/powernv/pci.h
@@ -193,6 +193,7 @@ extern void pnv_pci_dma_dev_setup(struct pci_dev *pdev);
 extern void pnv_pci_dma_bus_setup(struct pci_bus *bus);
 extern int pnv_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type);
 extern void pnv_teardown_msi_irqs(struct pci_dev *pdev);
+extern struct pnv_ioda_pe *__pnv_ioda_get_pe(struct pnv_phb *phb, u16 bdfn);
 extern struct pnv_ioda_pe *pnv_ioda_get_pe(struct pci_dev *dev);
 extern void pnv_set_msi_irq_chip(struct pnv_phb *phb, unsigned int virq);
 extern unsigned long pnv_pci_ioda2_get_table_size(__u32 page_shift,
-- 
2.21.0