Support multiple flash instances in embassy-boot

* Add FlashProvider and FlashConfig traits to define flash
characteristics
* Use traits in bootloader to retrieve flash handles and for
copying data between flash instances
* Add convenience implementations for using a single flash instance.

embassy-boot/nrf/.cargo/config.toml

@@ -1,5 +1,4 @@
 [unstable]
-namespaced-features = true
 build-std = ["core"]
 build-std-features = ["panic_immediate_abort"]
 

embassy-boot/nrf/Cargo.toml

@@ -12,7 +12,7 @@ defmt = { version = "0.3", optional = true }
 defmt-rtt = { version = "0.3", optional = true }
 
 embassy = { path = "../../embassy", default-features = false }
-embassy-nrf = { path = "../../embassy-nrf", default-features = false }
+embassy-nrf = { path = "../../embassy-nrf", default-features = false, features = ["nightly"] }
 embassy-boot = { path = "../boot", default-features = false }
 cortex-m = { version = "0.7" }
 cortex-m-rt = { version = "0.7" }

embassy-boot/nrf/src/lib.rs

@@ -4,7 +4,9 @@
 
 mod fmt;
 
-pub use embassy_boot::{FirmwareUpdater, Partition, State, BOOT_MAGIC};
+pub use embassy_boot::{
+    FirmwareUpdater, FlashProvider, Partition, SingleFlashProvider, State, BOOT_MAGIC,
+};
 use embassy_nrf::{
     nvmc::{Nvmc, PAGE_SIZE},
     peripherals::WDT,
@@ -62,7 +64,7 @@ impl BootLoader {
     }
 
     /// Boots the application without softdevice mechanisms
-    pub fn prepare<F: NorFlash + ReadNorFlash>(&mut self, flash: &mut F) -> usize {
+    pub fn prepare<F: FlashProvider>(&mut self, flash: &mut F) -> usize {
         match self.boot.prepare_boot(flash) {
             Ok(_) => self.boot.boot_address(),
             Err(_) => panic!("boot prepare error!"),

embassy-boot/nrf/src/main.rs

@@ -22,7 +22,11 @@ fn main() -> ! {
     */
 
     let mut bl = BootLoader::default();
-    let start = bl.prepare(&mut WatchdogFlash::start(Nvmc::new(p.NVMC), p.WDT, 5));
+    let start = bl.prepare(&mut SingleFlashProvider::new(&mut WatchdogFlash::start(
+        Nvmc::new(p.NVMC),
+        p.WDT,
+        5,
+    )));
     unsafe { bl.load(start) }
 }