PCIE_ECAM_BUS_SHIFT
ecam_bus_mask = (pcie->ecam_size >> PCIE_ECAM_BUS_SHIFT) - 1;
nr_buses = resource_size(config_res) >> PCIE_ECAM_BUS_SHIFT;
bus_shift = PCIE_ECAM_BUS_SHIFT;
#define PCIE_ECAM_BUS(x) (((x) & PCIE_ECAM_BUS_MASK) << PCIE_ECAM_BUS_SHIFT)