Add stm32 flash + bootloader support

* Add flash drivers for L0, L1, L4, WB and WL. Not tested for WB, but
should be similar to WL.
* Add embassy-boot-stm32 for bootloading on STM32.
* Add flash examples and bootloader examples
* Update stm32-data

embassy-boot/stm32/src/lib.rs

@@ -0,0 +1,75 @@
+#![no_std]
+#![feature(generic_associated_types)]
+#![feature(type_alias_impl_trait)]
+
+mod fmt;
+
+pub use embassy_boot::{FirmwareUpdater, FlashProvider, Partition, SingleFlashProvider, State};
+
+pub struct BootLoader<const PAGE_SIZE: usize> {
+    boot: embassy_boot::BootLoader<PAGE_SIZE>,
+}
+
+impl<const PAGE_SIZE: usize> BootLoader<PAGE_SIZE> {
+    /// Create a new bootloader instance using parameters from linker script
+    pub fn default() -> Self {
+        extern "C" {
+            static __bootloader_state_start: u32;
+            static __bootloader_state_end: u32;
+            static __bootloader_active_start: u32;
+            static __bootloader_active_end: u32;
+            static __bootloader_dfu_start: u32;
+            static __bootloader_dfu_end: u32;
+        }
+
+        let active = unsafe {
+            Partition::new(
+                &__bootloader_active_start as *const u32 as usize,
+                &__bootloader_active_end as *const u32 as usize,
+            )
+        };
+        let dfu = unsafe {
+            Partition::new(
+                &__bootloader_dfu_start as *const u32 as usize,
+                &__bootloader_dfu_end as *const u32 as usize,
+            )
+        };
+        let state = unsafe {
+            Partition::new(
+                &__bootloader_state_start as *const u32 as usize,
+                &__bootloader_state_end as *const u32 as usize,
+            )
+        };
+
+        trace!("ACTIVE: 0x{:x} - 0x{:x}", active.from, active.to);
+        trace!("DFU: 0x{:x} - 0x{:x}", dfu.from, dfu.to);
+        trace!("STATE: 0x{:x} - 0x{:x}", state.from, state.to);
+
+        Self::new(active, dfu, state)
+    }
+
+    /// Create a new bootloader instance using the supplied partitions for active, dfu and state.
+    pub fn new(active: Partition, dfu: Partition, state: Partition) -> Self {
+        Self {
+            boot: embassy_boot::BootLoader::new(active, dfu, state),
+        }
+    }
+
+    /// Boots the application
+    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!"),
+        }
+    }
+
+    pub unsafe fn load(&mut self, start: usize) -> ! {
+        trace!("Loading app at 0x{:x}", start);
+        let mut p = cortex_m::Peripherals::steal();
+        #[cfg(not(feature = "thumbv6"))]
+        p.SCB.invalidate_icache();
+        p.SCB.vtor.write(start as u32);
+
+        cortex_m::asm::bootload(start as *const u32)
+    }
+}