Method allocate_device_id

pci/src/bus.rs:223–244

Allocates a PCI device ID on the bus. - `id`: ID to allocate on the bus. If [`None`], the next free device ID on the bus is allocated, else the ID given is allocated ## Errors Returns [`PciRootError::AlreadyInUsePciDeviceSlot`] in case the ID requested is already allocated. Returns [`PciRootError::InvalidPciDeviceSlot`] in case the requested ID exceeds the maximum number of devices allowed per

(&mut self, id: Option<u8>)

    ///   [`PciRootError::NoPciDeviceSlotAvailable`] if no free device
    ///   slot is available on the bus.
    pub fn allocate_device_id(&mut self, id: Option<u8>) -> Result<u8> {
        if let Some(idx) = id.map(|i| i as usize) {
            if idx < NUM_DEVICE_IDS as usize {
                if self.device_ids[idx] == DeviceIdState::Allocated {
                    Err(PciRootError::AlreadyInUsePciDeviceSlot(idx))
                } else {
                    self.device_ids[idx] = DeviceIdState::Allocated;
                    Ok(idx as u8)
                }
            } else {
                Err(PciRootError::InvalidPciDeviceSlot(idx))
            }
        } else {
            for (idx, device_id) in self.device_ids.iter_mut().enumerate() {
                if *device_id == DeviceIdState::Free {
                    *device_id = DeviceIdState::Allocated;
                    return Ok(idx as u8);
                }
            }
            Err(PciRootError::NoPciDeviceSlotAvailable)
        }
    }

    /// Frees a PCI device ID on the bus.
    ///