powerpc/powernv/pci: Add helper to check if a PE has a single vendor

Add a helper that determines if all the devices contained in a given PE
are all from the same vendor or not.  This can be useful in determining
if it's okay to make PE-wide changes that may be suitable for some
devices but not for others.

This is used later in the series.

Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 96d0156f48db88a6169d20b6611fb94a738f287a..a6424127ca8da834d090ab4a76904fa6d1633b29 100644 (file)
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1718,6 +1718,31 @@ static void pnv_pci_ioda_dma_dev_setup(struct pnv_phb *phb, struct pci_dev *pdev
         */
 }
 
+static bool pnv_pci_ioda_pe_single_vendor(struct pnv_ioda_pe *pe)
+{
+       unsigned short vendor = 0;
+       struct pci_dev *pdev;
+
+       if (pe->device_count == 1)
+               return true;
+
+       /* pe->pdev should be set if it's a single device, pe->pbus if not */
+       if (!pe->pbus)
+               return true;
+
+       list_for_each_entry(pdev, &pe->pbus->devices, bus_list) {
+               if (!vendor) {
+                       vendor = pdev->vendor;
+                       continue;
+               }
+
+               if (pdev->vendor != vendor)
+                       return false;
+       }
+
+       return true;
+}
+
 static int pnv_pci_ioda_dma_set_mask(struct pci_dev *pdev, u64 dma_mask)
 {
        struct pci_controller *hose = pci_bus_to_host(pdev->bus);