Finished flashloader and bootloader implementation

bootloader/Cargo.toml

@@ -7,12 +7,11 @@ edition = "2021"
 cortex-m = "0.7"
 cortex-m-rt = "0.7"
 embedded-hal = "1"
-embedded-hal-bus = "0.2"
-dummy-pin = "1"
 panic-rtt-target = { version = "0.1.3" }
 panic-halt = { version = "0.2" }
 rtt-target = { version = "0.5" }
 crc = "3"
+static_assertions = "1"
 
 [dependencies.va108xx-hal]
 path = "../va108xx-hal"

bootloader/README.md

@@ -0,0 +1,48 @@
+VA108xx Bootloader Application
+=======
+
+This is the Rust version of the bootloader supplied by Vorago.
+
+## Memory Map
+
+The bootloader uses the following memory map:
+
+| Address | Notes | Size |
+| ------ | ---- |  ---- |
+| 0x0 | Bootloader start | code up to 0x3FFC bytes |
+| 0x2FFE | Bootloader CRC | word |
+| 0x3000 | App image A start | code up to 0xE7F8 (~58K) bytes |
+| 0x117F8 | App image A CRC check length | word |
+| 0x117FC | App image A CRC check value | word |
+| 0x11800 | App image B start | code up to 0xE7F8 (~58K) bytes |
+| 0x1FFF8 | App image B CRC check length | word |
+| 0x1FFFC | App image B CRC check value | word |
+| 0x20000 | End of NVM | end  |
+
+## Additional Information
+
+This bootloader was specifically written for the REB1 board, so it assumes a M95M01 ST EEPROM
+is used to load the application code. The bootloader will also delay for a configurable amount
+of time before booting. This allows to catch the RTT printout, but should probably be disabled
+for production firmware.
+
+This bootloader does not provide tools to flash the NVM memory by itself. Instead, you can use
+the [flashloader](https://egit.irs.uni-stuttgart.de/rust/va108xx-rs/src/branch/main/flashloader)
+application to perform this task using a CCSDS interface via a UART.
+
+The bootloader performs the following steps:
+
+1. The application will calculate the checksum of itself if the bootloader CRC is blank (all zeroes
+   or all ones). If the CRC is not blank and the checksum check fails, it will immediately boot
+   application image A. Otherwise, it proceeds to the next step.
+2. Check the checksum of App A. If that checksum is valid, it will boot App A. If not, it will
+   proceed to the next step.
+3. Check the checksum of App B. If that checksum is valid, it will boot App B. If not, it will
+   boot App A as the fallback image.
+
+You could adapt and combine this bootloader with a non-volatile memory to select a prefered app
+image, which would be a first step towards an updatable flight software.
+
+Please note that you *MUST* compile the application at slot A and slot B with an appropriate
+`memory.x` file where the base address of the `FLASH` was adapted according to the base address
+shown in the memory map above. The memory files to do this were provided in the `scripts` folder.

bootloader/src/lib.rs

@@ -4,7 +4,7 @@ use core::convert::Infallible;
 
 /// Simple trait which makes swapping the NVM easier. NVMs only need to implement this interface.
 pub trait NvmInterface {
-    fn write(&mut self, address: u32, data: &[u8]) -> Result<(), Infallible>;
-    fn read(&mut self, address: u32, buf: &mut [u8]) -> Result<(), Infallible>;
-    fn verify(&mut self, address: u32, data: &[u8]) -> Result<bool, Infallible>;
+    fn write(&mut self, address: usize, data: &[u8]) -> Result<(), Infallible>;
+    fn read(&mut self, address: usize, buf: &mut [u8]) -> Result<(), Infallible>;
+    fn verify(&mut self, address: usize, data: &[u8]) -> Result<bool, Infallible>;
 }

bootloader/src/main.rs

@@ -4,18 +4,21 @@
 use bootloader::NvmInterface;
 use cortex_m_rt::entry;
 use crc::{Crc, CRC_16_IBM_3740};
+use embedded_hal::delay::DelayNs;
 #[cfg(not(feature = "rtt-panic"))]
 use panic_halt as _;
 #[cfg(feature = "rtt-panic")]
 use panic_rtt_target as _;
 use rtt_target::{rprintln, rtt_init_print};
-use va108xx_hal::{pac, time::Hertz};
+use va108xx_hal::{pac, time::Hertz, timer::CountdownTimer};
 use vorago_reb1::m95m01::M95M01;
 
 // Useful for debugging and see what the bootloader is doing. Enabled currently, because
 // the binary stays small enough.
 const RTT_PRINTOUT: bool = true;
-const DEBUG_PRINTOUTS: bool = false;
+const DEBUG_PRINTOUTS: bool = true;
+// Small delay, allows RTT printout to catch up.
+const BOOT_DELAY_MS: u32 = 2000;
 
 // Dangerous option! An image with this option set to true will flash itself from RAM directly
 // into the NVM. This can be used as a recovery option from a direct RAM flash to fix the NVM
@@ -35,23 +38,32 @@ const CLOCK_FREQ: Hertz = Hertz::from_raw(50_000_000);
 
 // Important bootloader addresses and offsets, vector table information.
 
+const NVM_SIZE: u32 = 0x20000;
 const BOOTLOADER_START_ADDR: u32 = 0x0;
 const BOOTLOADER_CRC_ADDR: u32 = BOOTLOADER_END_ADDR - 2;
 // This is also the maximum size of the bootloader.
 const BOOTLOADER_END_ADDR: u32 = 0x3000;
-const APP_A_START_ADDR: u32 = 0x3000;
+const APP_A_START_ADDR: u32 = BOOTLOADER_END_ADDR;
+// 0x117F8
 const APP_A_SIZE_ADDR: u32 = APP_A_END_ADDR - 8;
 // Four bytes reserved, even when only 2 byte CRC is used. Leaves flexibility to switch to CRC32.
+// 0x117FC
 const APP_A_CRC_ADDR: u32 = APP_A_END_ADDR - 4;
-pub const APP_A_END_ADDR: u32 = 0x11000;
+// 0x11800
+pub const APP_A_END_ADDR: u32 = APP_A_START_ADDR + APP_IMG_SZ;
 // The actual size of the image which is relevant for CRC calculation.
-const APP_B_START_ADDR: u32 = 0x11000;
+const APP_B_START_ADDR: u32 = APP_A_END_ADDR;
 // The actual size of the image which is relevant for CRC calculation.
+// 0x1FFF8
 const APP_B_SIZE_ADDR: u32 = APP_B_END_ADDR - 8;
 // Four bytes reserved, even when only 2 byte CRC is used. Leaves flexibility to switch to CRC32.
+// 0x1FFFC
 const APP_B_CRC_ADDR: u32 = APP_B_END_ADDR - 4;
-pub const APP_B_END_ADDR: u32 = 0x20000;
-pub const APP_IMG_SZ: u32 = 0xE800;
+// 0x20000
+pub const APP_B_END_ADDR: u32 = NVM_SIZE;
+pub const APP_IMG_SZ: u32 = (APP_B_END_ADDR - APP_A_START_ADDR) / 2;
+
+static_assertions::const_assert!((APP_B_END_ADDR - BOOTLOADER_END_ADDR) % 2 == 0);
 
 pub const VECTOR_TABLE_OFFSET: u32 = 0x0;
 pub const VECTOR_TABLE_LEN: u32 = 0xC0;
@@ -69,15 +81,15 @@ pub struct NvmWrapper(pub M95M01);
 
 // Newtype pattern. We could now more easily swap the used NVM type.
 impl NvmInterface for NvmWrapper {
-    fn write(&mut self, address: u32, data: &[u8]) -> Result<(), core::convert::Infallible> {
+    fn write(&mut self, address: usize, data: &[u8]) -> Result<(), core::convert::Infallible> {
         self.0.write(address, data)
     }
 
-    fn read(&mut self, address: u32, buf: &mut [u8]) -> Result<(), core::convert::Infallible> {
+    fn read(&mut self, address: usize, buf: &mut [u8]) -> Result<(), core::convert::Infallible> {
         self.0.read(address, buf)
     }
 
-    fn verify(&mut self, address: u32, data: &[u8]) -> Result<bool, core::convert::Infallible> {
+    fn verify(&mut self, address: usize, data: &[u8]) -> Result<bool, core::convert::Infallible> {
         self.0.verify(address, data)
     }
 }
@@ -90,6 +102,7 @@ fn main() -> ! {
     }
     let mut dp = pac::Peripherals::take().unwrap();
     let cp = cortex_m::Peripherals::take().unwrap();
+    let mut timer = CountdownTimer::new(&mut dp.sysconfig, CLOCK_FREQ, dp.tim0);
 
     let mut nvm = M95M01::new(&mut dp.sysconfig, CLOCK_FREQ, dp.spic);
 
@@ -124,9 +137,9 @@ fn main() -> ! {
             }
         }
 
-        nvm.write(BOOTLOADER_CRC_ADDR, &bootloader_crc.to_be_bytes())
+        nvm.write(BOOTLOADER_CRC_ADDR as usize, &bootloader_crc.to_be_bytes())
             .expect("writing CRC failed");
-        if let Err(e) = nvm.verify(BOOTLOADER_CRC_ADDR, &bootloader_crc.to_be_bytes()) {
+        if let Err(e) = nvm.verify(BOOTLOADER_CRC_ADDR as usize, &bootloader_crc.to_be_bytes()) {
             if RTT_PRINTOUT {
                 rprintln!(
                     "error: CRC verification for bootloader self-flash failed: {:?}",
@@ -139,23 +152,28 @@ fn main() -> ! {
     let mut nvm = NvmWrapper(nvm);
 
     // Check bootloader's CRC (and write it if blank)
-    check_own_crc(&dp.sysconfig, &cp, &mut nvm);
+    check_own_crc(&dp.sysconfig, &cp, &mut nvm, &mut timer);
 
     if check_app_crc(AppSel::A) {
-        boot_app(&dp.sysconfig, &cp, AppSel::A)
+        boot_app(&dp.sysconfig, &cp, AppSel::A, &mut timer)
     } else if check_app_crc(AppSel::B) {
-        boot_app(&dp.sysconfig, &cp, AppSel::B)
+        boot_app(&dp.sysconfig, &cp, AppSel::B, &mut timer)
     } else {
         if DEBUG_PRINTOUTS && RTT_PRINTOUT {
             rprintln!("both images corrupt! booting image A");
         }
         // TODO: Shift a CCSDS packet out to inform host/OBC about image corruption.
         // Both images seem to be corrupt. Boot default image A.
-        boot_app(&dp.sysconfig, &cp, AppSel::A)
+        boot_app(&dp.sysconfig, &cp, AppSel::A, &mut timer)
     }
 }
 
-fn check_own_crc(sysconfig: &pac::Sysconfig, cp: &cortex_m::Peripherals, nvm: &mut NvmWrapper) {
+fn check_own_crc(
+    sysconfig: &pac::Sysconfig,
+    cp: &cortex_m::Peripherals,
+    nvm: &mut NvmWrapper,
+    timer: &mut CountdownTimer<pac::Tim0>,
+) {
     let crc_exp = unsafe { (BOOTLOADER_CRC_ADDR as *const u16).read_unaligned().to_be() };
     // I'd prefer to use [core::slice::from_raw_parts], but that is problematic
     // because the address of the bootloader is 0x0, so the NULL check fails and the functions
@@ -176,7 +194,7 @@ fn check_own_crc(sysconfig: &pac::Sysconfig, cp: &cortex_m::Peripherals, nvm: &m
             rprintln!("BL CRC blank - prog new CRC");
         }
         // Blank CRC, write it to NVM.
-        nvm.write(BOOTLOADER_CRC_ADDR, &crc_calc.to_be_bytes())
+        nvm.write(BOOTLOADER_CRC_ADDR as usize, &crc_calc.to_be_bytes())
             .expect("writing CRC failed");
         // The Vorago bootloader resets here. I am not sure why this is done but I think it is
         // necessary because somehow the boot will not work if we just continue as usual.
@@ -191,7 +209,7 @@ fn check_own_crc(sysconfig: &pac::Sysconfig, cp: &cortex_m::Peripherals, nvm: &m
             );
         }
         // TODO: Shift out minimal CCSDS frame to notify about bootloader corruption.
-        boot_app(sysconfig, cp, AppSel::A);
+        boot_app(sysconfig, cp, AppSel::A, timer);
     }
 }
 
@@ -240,43 +258,52 @@ fn check_app_given_addr(crc_addr: u32, start_addr: u32, image_size_addr: u32) ->
 
 // The boot works by copying the interrupt vector table (IVT) of the respective app to the
 // base address in code RAM (0x0) and then performing a soft reset.
-fn boot_app(syscfg: &pac::Sysconfig, cp: &cortex_m::Peripherals, app_sel: AppSel) -> ! {
+fn boot_app(
+    syscfg: &pac::Sysconfig,
+    cp: &cortex_m::Peripherals,
+    app_sel: AppSel,
+    timer: &mut CountdownTimer<pac::Tim0>,
+) -> ! {
     if DEBUG_PRINTOUTS && RTT_PRINTOUT {
         rprintln!("booting app {:?}", app_sel);
     }
+    timer.delay_ms(BOOT_DELAY_MS);
+
+    // Clear all interrupts set.
+    unsafe {
+        cp.NVIC.icer[0].write(0xFFFFFFFF);
+        cp.NVIC.icpr[0].write(0xFFFFFFFF);
+    }
     // Disable ROM protection.
-    syscfg.rom_prot().write(|w| unsafe { w.bits(1) });
+    syscfg.rom_prot().write(|w| w.wren().set_bit());
     let base_addr = if app_sel == AppSel::A {
         APP_A_START_ADDR
     } else {
         APP_B_START_ADDR
     };
-    // Clear all interrupts set.
     unsafe {
-        cp.NVIC.icer[0].write(0xFFFFFFFF);
-        cp.NVIC.icpr[0].write(0xFFFFFFFF);
-
         // First 4 bytes done with inline assembly, writing to the physical address 0x0 can not
         // be done without it. See https://users.rust-lang.org/t/reading-from-physical-address-0x0/117408/2.
-        core::ptr::read(base_addr as *const u32);
+        let first_four_bytes = core::ptr::read(base_addr as *const u32);
         core::arch::asm!(
-            "str {0}, [{1}]",    // Load 4 bytes from src into r0 register
-            in(reg)  base_addr,  // Input: App vector table.
+            "str {0}, [{1}]",
+            in(reg)  first_four_bytes,  // Input: App vector table.
             in(reg) BOOTLOADER_START_ADDR as *mut u32,  // Input: destination pointer
         );
         core::slice::from_raw_parts_mut(
-            (BOOTLOADER_START_ADDR + 4) as *mut u32,
+            (BOOTLOADER_START_ADDR + 4) as *mut u8,
             (VECTOR_TABLE_LEN - 4) as usize,
         )
         .copy_from_slice(core::slice::from_raw_parts(
-            (base_addr + 4) as *const u32,
+            (base_addr + 4) as *const u8,
             (VECTOR_TABLE_LEN - 4) as usize,
         ));
     }
-    /* Disable re-loading from FRAM/code ROM on soft reset */
+    // Disable re-loading from FRAM/code ROM on soft reset
     syscfg
         .rst_cntl_rom()
         .modify(|_, w| w.sysrstreq().clear_bit());
+
     soft_reset(cp);
 }
 
@@ -292,5 +319,8 @@ fn soft_reset(cp: &cortex_m::Peripherals) -> ! {
     // Ensure completion of memory access.
     cortex_m::asm::dsb();
 
-    unreachable!();
+    // Loop until the reset occurs.
+    loop {
+        cortex_m::asm::nop();
+    }
 }