rp: add precompiled boot2 to avoid depending on gcc

embassy-rp-examples/.cargo/config

@@ -9,19 +9,9 @@ rustflags = [
   # LLD (shipped with the Rust toolchain) is used as the default linker
   "-C", "link-arg=--nmagic",
   "-C", "link-arg=-Tlink.x",
+  "-C", "link-arg=-Tlink-rp.x",
   "-C", "link-arg=-Tdefmt.x",
 
-  # if you run into problems with LLD switch to the GNU linker by commenting out
-  # this line
-  # "-C", "linker=arm-none-eabi-ld",
-
-  # if you need to link to pre-compiled C libraries provided by a C toolchain
-  # use GCC as the linker by commenting out both lines above and then
-  # uncommenting the three lines below
-  # "-C", "linker=arm-none-eabi-gcc",
-  # "-C", "link-arg=-Wl,-Tlink.x",
-  # "-C", "link-arg=-nostartfiles",
-
   # Code-size optimizations.
   "-Z", "trap-unreachable=no",
 ]

embassy-rp-examples/Cargo.toml

@@ -19,7 +19,6 @@ defmt-error = []
 [dependencies]
 embassy = { version = "0.1.0", path = "../embassy", features = ["defmt", "defmt-trace"] }
 embassy-rp = { version = "0.1.0", path = "../embassy-rp", features = ["defmt", "defmt-trace"] }
-rp2040-boot2 = { git = "https://github.com/rp-rs/rp2040-boot2-rs", branch="main" }
 rp2040-pac2 = { git = "https://github.com/Dirbaio/rp2040-pac", rev="254f4677937801155ca3cb17c7bb9d38eb62683e" }
 atomic-polyfill = { version = "0.1.1" }
 

embassy-rp-examples/memory.x

@@ -2,12 +2,4 @@ MEMORY {
     BOOT2 : ORIGIN = 0x10000000, LENGTH = 0x100
     FLASH : ORIGIN = 0x10000100, LENGTH = 2048K - 0x100
     RAM   : ORIGIN = 0x20000000, LENGTH = 256K
-}
+}
-
-SECTIONS {
-    /* ### Boot loader */
-    .boot2 ORIGIN(BOOT2) :
-    {
-        KEEP(*(.boot2));
-    } > BOOT2
-} INSERT BEFORE .text;

embassy-rp-examples/src/example_common.rs

@@ -2,10 +2,6 @@ use core::sync::atomic::{AtomicUsize, Ordering};
 use defmt_rtt as _;
 use panic_probe as _;
 
-#[link_section = ".boot2"]
-#[used]
-pub static BOOT2: [u8; 256] = rp2040_boot2::BOOT_LOADER;
-
 defmt::timestamp! {"{=u64}", {
     static COUNT: AtomicUsize = AtomicUsize::new(0);
     // NOTE(no-CAS) `timestamps` runs with interrupts disabled

embassy-rp/build.rs

@@ -0,0 +1,17 @@
+use std::fs::{self, File};
+use std::io::Write;
+use std::path::{Path, PathBuf};
+use std::{env, ffi::OsStr};
+
+fn main() {
+    // Put the linker script somewhere the linker can find it
+    let out = &PathBuf::from(env::var_os("OUT_DIR").unwrap());
+    let link_x = include_bytes!("link-rp.x.in");
+    let mut f = File::create(out.join("link-rp.x")).unwrap();
+    f.write_all(link_x).unwrap();
+
+    println!("cargo:rustc-link-search={}", out.display());
+
+    println!("cargo:rerun-if-changed=build.rs");
+    println!("cargo:rerun-if-changed=link-rp.x.in");
+}

embassy-rp/link-rp.x.in

@@ -0,0 +1,8 @@
+
+SECTIONS {
+    /* ### Boot loader */
+    .boot2 ORIGIN(BOOT2) :
+    {
+        KEEP(*(.boot2));
+    } > BOOT2
+}

embassy-rp/src/system.rs

@@ -1,5 +1,9 @@
 use crate::{pac, pll, resets};
 
+#[link_section = ".boot2"]
+#[used]
+pub static BOOT2: [u8; 256] = *include_bytes!("boot2.bin");
+
 #[non_exhaustive]
 pub struct Config {}