pub fn pci_cfg_read(ctx: &ServiceContext, sel: u32, offset: u16) -> Option<u32>Expand description
Read one 32-bit register of a PCI function’s configuration space. sel is the platform’s own
bus/device/function encoding, which is the caller’s knowledge. None when the capability is missing
or the machine will not admit the access; Some(0xFFFF_FFFF) is a successful read of an absent
device, which is data.