525 lines
19 KiB
Rust
525 lines
19 KiB
Rust
use embedded_storage::nor_flash::{ErrorType, NorFlash, NorFlashError, NorFlashErrorKind, ReadNorFlash};
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use crate::{Partition, State, BOOT_MAGIC, SWAP_MAGIC};
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/// Errors returned by bootloader
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#[derive(PartialEq, Eq, Debug)]
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pub enum BootError {
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/// Error from flash.
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Flash(NorFlashErrorKind),
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/// Invalid bootloader magic
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BadMagic,
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}
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#[cfg(feature = "defmt")]
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impl defmt::Format for BootError {
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fn format(&self, fmt: defmt::Formatter) {
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match self {
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BootError::Flash(_) => defmt::write!(fmt, "BootError::Flash(_)"),
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BootError::BadMagic => defmt::write!(fmt, "BootError::BadMagic"),
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}
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}
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}
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impl<E> From<E> for BootError
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where
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E: NorFlashError,
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{
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fn from(error: E) -> Self {
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BootError::Flash(error.kind())
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}
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}
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/// Extension of the embedded-storage flash type information with block size and erase value.
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pub trait Flash: NorFlash + ReadNorFlash {
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/// The block size that should be used when writing to flash. For most builtin flashes, this is the same as the erase
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/// size of the flash, but for external QSPI flash modules, this can be lower.
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const BLOCK_SIZE: usize;
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/// The erase value of the flash. Typically the default of 0xFF is used, but some flashes use a different value.
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const ERASE_VALUE: u8 = 0xFF;
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}
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/// Trait defining the flash handles used for active and DFU partition
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pub trait FlashConfig {
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/// Flash type used for the state partition.
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type STATE: Flash;
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/// Flash type used for the active partition.
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type ACTIVE: Flash;
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/// Flash type used for the dfu partition.
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type DFU: Flash;
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/// Return flash instance used to write/read to/from active partition.
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fn active(&mut self) -> &mut Self::ACTIVE;
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/// Return flash instance used to write/read to/from dfu partition.
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fn dfu(&mut self) -> &mut Self::DFU;
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/// Return flash instance used to write/read to/from bootloader state.
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fn state(&mut self) -> &mut Self::STATE;
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}
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/// BootLoader works with any flash implementing embedded_storage and can also work with
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/// different page sizes and flash write sizes.
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pub struct BootLoader {
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// Page with current state of bootloader. The state partition has the following format:
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// | Range | Description |
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// | 0 - WRITE_SIZE | Magic indicating bootloader state. BOOT_MAGIC means boot, SWAP_MAGIC means swap. |
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// | WRITE_SIZE - N | Progress index used while swapping or reverting |
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state: Partition,
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// Location of the partition which will be booted from
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active: Partition,
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// Location of the partition which will be swapped in when requested
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dfu: Partition,
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}
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impl BootLoader {
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/// Create a new instance of a bootloader with the given partitions.
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///
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/// - All partitions must be aligned with the PAGE_SIZE const generic parameter.
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/// - The dfu partition must be at least PAGE_SIZE bigger than the active partition.
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pub fn new(active: Partition, dfu: Partition, state: Partition) -> Self {
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Self { active, dfu, state }
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}
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/// Return the offset of the active partition into the active flash.
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pub fn boot_address(&self) -> usize {
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self.active.from
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}
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/// Perform necessary boot preparations like swapping images.
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///
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/// The DFU partition is assumed to be 1 page bigger than the active partition for the swap
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/// algorithm to work correctly.
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///
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/// SWAPPING
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///
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/// Assume a flash size of 3 pages for the active partition, and 4 pages for the DFU partition.
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/// The swap index contains the copy progress, as to allow continuation of the copy process on
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/// power failure. The index counter is represented within 1 or more pages (depending on total
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/// flash size), where a page X is considered swapped if index at location (X + WRITE_SIZE)
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/// contains a zero value. This ensures that index updates can be performed atomically and
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/// avoid a situation where the wrong index value is set (page write size is "atomic").
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///
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/// +-----------+------------+--------+--------+--------+--------+
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/// | Partition | Swap Index | Page 0 | Page 1 | Page 3 | Page 4 |
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/// +-----------+------------+--------+--------+--------+--------+
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/// | Active | 0 | 1 | 2 | 3 | - |
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/// | DFU | 0 | 3 | 2 | 1 | X |
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/// +-----------+------------+--------+--------+--------+--------+
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///
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/// The algorithm starts by copying 'backwards', and after the first step, the layout is
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/// as follows:
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///
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/// +-----------+------------+--------+--------+--------+--------+
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/// | Partition | Swap Index | Page 0 | Page 1 | Page 3 | Page 4 |
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/// +-----------+------------+--------+--------+--------+--------+
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/// | Active | 1 | 1 | 2 | 1 | - |
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/// | DFU | 1 | 3 | 2 | 1 | 3 |
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/// +-----------+------------+--------+--------+--------+--------+
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///
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/// The next iteration performs the same steps
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///
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/// +-----------+------------+--------+--------+--------+--------+
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/// | Partition | Swap Index | Page 0 | Page 1 | Page 3 | Page 4 |
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/// +-----------+------------+--------+--------+--------+--------+
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/// | Active | 2 | 1 | 2 | 1 | - |
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/// | DFU | 2 | 3 | 2 | 2 | 3 |
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/// +-----------+------------+--------+--------+--------+--------+
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///
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/// And again until we're done
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///
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/// +-----------+------------+--------+--------+--------+--------+
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/// | Partition | Swap Index | Page 0 | Page 1 | Page 3 | Page 4 |
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/// +-----------+------------+--------+--------+--------+--------+
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/// | Active | 3 | 3 | 2 | 1 | - |
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/// | DFU | 3 | 3 | 1 | 2 | 3 |
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/// +-----------+------------+--------+--------+--------+--------+
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///
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/// REVERTING
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///
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/// The reverting algorithm uses the swap index to discover that images were swapped, but that
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/// the application failed to mark the boot successful. In this case, the revert algorithm will
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/// run.
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///
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/// The revert index is located separately from the swap index, to ensure that revert can continue
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/// on power failure.
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///
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/// The revert algorithm works forwards, by starting copying into the 'unused' DFU page at the start.
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///
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/// +-----------+--------------+--------+--------+--------+--------+
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/// | Partition | Revert Index | Page 0 | Page 1 | Page 3 | Page 4 |
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//*/
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/// +-----------+--------------+--------+--------+--------+--------+
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/// | Active | 3 | 1 | 2 | 1 | - |
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/// | DFU | 3 | 3 | 1 | 2 | 3 |
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/// +-----------+--------------+--------+--------+--------+--------+
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///
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///
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/// +-----------+--------------+--------+--------+--------+--------+
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/// | Partition | Revert Index | Page 0 | Page 1 | Page 3 | Page 4 |
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/// +-----------+--------------+--------+--------+--------+--------+
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/// | Active | 3 | 1 | 2 | 1 | - |
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/// | DFU | 3 | 3 | 2 | 2 | 3 |
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/// +-----------+--------------+--------+--------+--------+--------+
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///
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/// +-----------+--------------+--------+--------+--------+--------+
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/// | Partition | Revert Index | Page 0 | Page 1 | Page 3 | Page 4 |
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/// +-----------+--------------+--------+--------+--------+--------+
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/// | Active | 3 | 1 | 2 | 3 | - |
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/// | DFU | 3 | 3 | 2 | 1 | 3 |
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/// +-----------+--------------+--------+--------+--------+--------+
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///
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pub fn prepare_boot<P: FlashConfig>(
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&mut self,
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p: &mut P,
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magic: &mut [u8],
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page: &mut [u8],
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) -> Result<State, BootError> {
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// Ensure we have enough progress pages to store copy progress
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assert_partitions(self.active, self.dfu, self.state, page.len(), P::STATE::WRITE_SIZE);
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assert_eq!(magic.len(), P::STATE::WRITE_SIZE);
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// Copy contents from partition N to active
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let state = self.read_state(p, magic)?;
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if state == State::Swap {
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//
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// Check if we already swapped. If we're in the swap state, this means we should revert
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// since the app has failed to mark boot as successful
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//
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if !self.is_swapped(p, magic, page)? {
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trace!("Swapping");
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self.swap(p, magic, page)?;
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trace!("Swapping done");
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} else {
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trace!("Reverting");
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self.revert(p, magic, page)?;
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// Overwrite magic and reset progress
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let state_flash = p.state();
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magic.fill(!P::STATE::ERASE_VALUE);
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self.state.write_blocking(state_flash, 0, magic)?;
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self.state.wipe_blocking(state_flash)?;
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magic.fill(BOOT_MAGIC);
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self.state.write_blocking(state_flash, 0, magic)?;
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}
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}
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Ok(state)
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}
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fn is_swapped<P: FlashConfig>(&mut self, p: &mut P, magic: &mut [u8], page: &mut [u8]) -> Result<bool, BootError> {
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let page_size = page.len();
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let page_count = self.active.len() / page_size;
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let progress = self.current_progress(p, magic)?;
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Ok(progress >= page_count * 2)
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}
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fn current_progress<P: FlashConfig>(&mut self, config: &mut P, aligned: &mut [u8]) -> Result<usize, BootError> {
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let write_size = aligned.len();
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let max_index = ((self.state.len() - write_size) / write_size) - 1;
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aligned.fill(!P::STATE::ERASE_VALUE);
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let state_flash = config.state();
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for i in 0..max_index {
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self.state
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.read_blocking(state_flash, (write_size + i * write_size) as u32, aligned)?;
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if aligned.iter().any(|&b| b == P::STATE::ERASE_VALUE) {
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return Ok(i);
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}
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}
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Ok(max_index)
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}
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fn update_progress<P: FlashConfig>(&mut self, idx: usize, p: &mut P, magic: &mut [u8]) -> Result<(), BootError> {
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let write_size = magic.len();
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let aligned = magic;
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aligned.fill(!P::STATE::ERASE_VALUE);
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self.state
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.write_blocking(p.state(), (write_size + idx * write_size) as u32, aligned)?;
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Ok(())
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}
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fn copy_page_once_to_active<P: FlashConfig>(
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&mut self,
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idx: usize,
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from_offset: u32,
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to_offset: u32,
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p: &mut P,
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magic: &mut [u8],
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page: &mut [u8],
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) -> Result<(), BootError> {
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let buf = page;
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if self.current_progress(p, magic)? <= idx {
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let mut offset = from_offset;
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for chunk in buf.chunks_mut(P::DFU::BLOCK_SIZE) {
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self.dfu.read_blocking(p.dfu(), offset, chunk)?;
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offset += chunk.len() as u32;
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}
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self.active
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.erase_blocking(p.active(), to_offset, to_offset + buf.len() as u32)?;
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let mut offset = to_offset;
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for chunk in buf.chunks(P::ACTIVE::BLOCK_SIZE) {
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self.active.write_blocking(p.active(), offset, chunk)?;
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offset += chunk.len() as u32;
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}
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self.update_progress(idx, p, magic)?;
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}
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Ok(())
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}
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fn copy_page_once_to_dfu<P: FlashConfig>(
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&mut self,
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idx: usize,
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from_offset: u32,
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to_offset: u32,
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p: &mut P,
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magic: &mut [u8],
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page: &mut [u8],
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) -> Result<(), BootError> {
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let buf = page;
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if self.current_progress(p, magic)? <= idx {
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let mut offset = from_offset;
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for chunk in buf.chunks_mut(P::ACTIVE::BLOCK_SIZE) {
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self.active.read_blocking(p.active(), offset, chunk)?;
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offset += chunk.len() as u32;
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}
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self.dfu
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.erase_blocking(p.dfu(), to_offset as u32, to_offset + buf.len() as u32)?;
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let mut offset = to_offset;
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for chunk in buf.chunks(P::DFU::BLOCK_SIZE) {
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self.dfu.write_blocking(p.dfu(), offset, chunk)?;
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offset += chunk.len() as u32;
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}
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self.update_progress(idx, p, magic)?;
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}
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Ok(())
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}
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fn swap<P: FlashConfig>(&mut self, p: &mut P, magic: &mut [u8], page: &mut [u8]) -> Result<(), BootError> {
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let page_size = page.len();
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let page_count = self.active.len() / page_size;
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trace!("Page count: {}", page_count);
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for page_num in 0..page_count {
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trace!("COPY PAGE {}", page_num);
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let idx = page_num * 2;
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// Copy active page to the 'next' DFU page.
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let active_from_offset = ((page_count - 1 - page_num) * page_size) as u32;
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let dfu_to_offset = ((page_count - page_num) * page_size) as u32;
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//trace!("Copy active {} to dfu {}", active_from_offset, dfu_to_offset);
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self.copy_page_once_to_dfu(idx, active_from_offset, dfu_to_offset, p, magic, page)?;
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// Copy DFU page to the active page
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let active_to_offset = ((page_count - 1 - page_num) * page_size) as u32;
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let dfu_from_offset = ((page_count - 1 - page_num) * page_size) as u32;
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//trace!("Copy dfy {} to active {}", dfu_from_offset, active_to_offset);
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self.copy_page_once_to_active(idx + 1, dfu_from_offset, active_to_offset, p, magic, page)?;
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}
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Ok(())
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}
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fn revert<P: FlashConfig>(&mut self, p: &mut P, magic: &mut [u8], page: &mut [u8]) -> Result<(), BootError> {
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let page_size = page.len();
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let page_count = self.active.len() / page_size;
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for page_num in 0..page_count {
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let idx = page_count * 2 + page_num * 2;
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// Copy the bad active page to the DFU page
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let active_from_offset = (page_num * page_size) as u32;
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let dfu_to_offset = (page_num * page_size) as u32;
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self.copy_page_once_to_dfu(idx, active_from_offset, dfu_to_offset, p, magic, page)?;
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// Copy the DFU page back to the active page
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let active_to_offset = (page_num * page_size) as u32;
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let dfu_from_offset = ((page_num + 1) * page_size) as u32;
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self.copy_page_once_to_active(idx + 1, dfu_from_offset, active_to_offset, p, magic, page)?;
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}
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Ok(())
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}
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fn read_state<P: FlashConfig>(&mut self, config: &mut P, magic: &mut [u8]) -> Result<State, BootError> {
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self.state.read_blocking(config.state(), 0, magic)?;
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if !magic.iter().any(|&b| b != SWAP_MAGIC) {
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Ok(State::Swap)
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} else {
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Ok(State::Boot)
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}
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}
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}
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fn assert_partitions(active: Partition, dfu: Partition, state: Partition, page_size: usize, write_size: usize) {
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assert_eq!(active.len() % page_size, 0);
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assert_eq!(dfu.len() % page_size, 0);
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assert!(dfu.len() - active.len() >= page_size);
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assert!(2 * (active.len() / page_size) <= (state.len() - write_size) / write_size);
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}
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/// A flash wrapper implementing the Flash and embedded_storage traits.
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pub struct BootFlash<F, const BLOCK_SIZE: usize, const ERASE_VALUE: u8 = 0xFF>
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where
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F: NorFlash + ReadNorFlash,
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{
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flash: F,
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}
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impl<F, const BLOCK_SIZE: usize, const ERASE_VALUE: u8> BootFlash<F, BLOCK_SIZE, ERASE_VALUE>
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where
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F: NorFlash + ReadNorFlash,
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{
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/// Create a new instance of a bootable flash
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pub fn new(flash: F) -> Self {
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Self { flash }
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}
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}
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impl<F, const BLOCK_SIZE: usize, const ERASE_VALUE: u8> Flash for BootFlash<F, BLOCK_SIZE, ERASE_VALUE>
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where
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F: NorFlash + ReadNorFlash,
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{
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const BLOCK_SIZE: usize = BLOCK_SIZE;
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const ERASE_VALUE: u8 = ERASE_VALUE;
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}
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impl<F, const BLOCK_SIZE: usize, const ERASE_VALUE: u8> ErrorType for BootFlash<F, BLOCK_SIZE, ERASE_VALUE>
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where
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F: ReadNorFlash + NorFlash,
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{
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type Error = F::Error;
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}
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impl<F, const BLOCK_SIZE: usize, const ERASE_VALUE: u8> NorFlash for BootFlash<F, BLOCK_SIZE, ERASE_VALUE>
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where
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F: ReadNorFlash + NorFlash,
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{
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const WRITE_SIZE: usize = F::WRITE_SIZE;
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const ERASE_SIZE: usize = F::ERASE_SIZE;
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fn erase(&mut self, from: u32, to: u32) -> Result<(), Self::Error> {
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F::erase(&mut self.flash, from, to)
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}
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fn write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Self::Error> {
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F::write(&mut self.flash, offset, bytes)
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}
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}
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impl<F, const BLOCK_SIZE: usize, const ERASE_VALUE: u8> ReadNorFlash for BootFlash<F, BLOCK_SIZE, ERASE_VALUE>
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where
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F: ReadNorFlash + NorFlash,
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{
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const READ_SIZE: usize = F::READ_SIZE;
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fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Self::Error> {
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F::read(&mut self.flash, offset, bytes)
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}
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fn capacity(&self) -> usize {
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F::capacity(&self.flash)
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}
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}
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/// Convenience provider that uses a single flash for all partitions.
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pub struct SingleFlashConfig<'a, F>
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where
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F: Flash,
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{
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flash: &'a mut F,
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}
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impl<'a, F> SingleFlashConfig<'a, F>
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where
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F: Flash,
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{
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/// Create a provider for a single flash.
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pub fn new(flash: &'a mut F) -> Self {
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Self { flash }
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}
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}
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impl<'a, F> FlashConfig for SingleFlashConfig<'a, F>
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where
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F: Flash,
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{
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type STATE = F;
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type ACTIVE = F;
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type DFU = F;
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fn active(&mut self) -> &mut Self::STATE {
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self.flash
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}
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fn dfu(&mut self) -> &mut Self::ACTIVE {
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self.flash
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}
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fn state(&mut self) -> &mut Self::DFU {
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self.flash
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}
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}
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/// Convenience flash provider that uses separate flash instances for each partition.
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pub struct MultiFlashConfig<'a, ACTIVE, STATE, DFU>
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where
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|
ACTIVE: Flash,
|
|
STATE: Flash,
|
|
DFU: Flash,
|
|
{
|
|
active: &'a mut ACTIVE,
|
|
state: &'a mut STATE,
|
|
dfu: &'a mut DFU,
|
|
}
|
|
|
|
impl<'a, ACTIVE, STATE, DFU> MultiFlashConfig<'a, ACTIVE, STATE, DFU>
|
|
where
|
|
ACTIVE: Flash,
|
|
STATE: Flash,
|
|
DFU: Flash,
|
|
{
|
|
/// Create a new flash provider with separate configuration for all three partitions.
|
|
pub fn new(active: &'a mut ACTIVE, state: &'a mut STATE, dfu: &'a mut DFU) -> Self {
|
|
Self { active, state, dfu }
|
|
}
|
|
}
|
|
|
|
impl<'a, ACTIVE, STATE, DFU> FlashConfig for MultiFlashConfig<'a, ACTIVE, STATE, DFU>
|
|
where
|
|
ACTIVE: Flash,
|
|
STATE: Flash,
|
|
DFU: Flash,
|
|
{
|
|
type STATE = STATE;
|
|
type ACTIVE = ACTIVE;
|
|
type DFU = DFU;
|
|
|
|
fn active(&mut self) -> &mut Self::ACTIVE {
|
|
self.active
|
|
}
|
|
fn dfu(&mut self) -> &mut Self::DFU {
|
|
self.dfu
|
|
}
|
|
fn state(&mut self) -> &mut Self::STATE {
|
|
self.state
|
|
}
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod tests {
|
|
use super::*;
|
|
|
|
#[test]
|
|
#[should_panic]
|
|
fn test_range_asserts() {
|
|
const ACTIVE: Partition = Partition::new(4096, 4194304);
|
|
const DFU: Partition = Partition::new(4194304, 2 * 4194304);
|
|
const STATE: Partition = Partition::new(0, 4096);
|
|
assert_partitions(ACTIVE, DFU, STATE, 4096, 4);
|
|
}
|
|
}
|