Module capsules_core::virtualizers::virtual_flash

Virtualize writing flash.

MuxFlash provides shared access to a flash interface from multiple clients in the kernel. For instance, a board may wish to expose the internal MCU flash for multiple uses, like allowing userland apps to write their own flash space, and to provide a “scratch space” as the end of flash for all apps to use. Each of these requires a capsule to support the operation, and must use a FlashUser instance to contain the per-user state for the virtualization.

Usage

// Create the mux.
let mux_flash = static_init!(
    capsules_core::virtual_flash::MuxFlash<'static, sam4l::flashcalw::FLASHCALW>,
    capsules_core::virtual_flash::MuxFlash::new(&sam4l::flashcalw::FLASH_CONTROLLER));
hil::flash::HasClient::set_client(&sam4l::flashcalw::FLASH_CONTROLLER, mux_flash);

// Everything that then uses the virtualized flash must use one of these.
let virtual_flash = static_init!(
    capsules_core::virtual_flash::FlashUser<'static, sam4l::flashcalw::FLASHCALW>,
    capsules_core::virtual_flash::FlashUser::new(mux_flash));

Structs

• FlashUser
  Keep state for each flash user. All uses of the virtualized flash interface need to create one of these to be a user of the flash. The new() function handles most of the work, a user only has to pass in a reference to the MuxFlash object.
• MuxFlash
  Handle keeping a list of active users of flash hardware and serialize their requests. After each completed request the list is checked to see if there is another flash user with an outstanding read, write, or erase request.