Add RP2350 support

Author: konkers

Diff for: README.md

@@ -1,6 +1,6 @@
-# RaspberryPi Pico RP2040 flash algorithm
+# RaspberryPi Pico RP2 flash algorithm
 
-This is a flash algorithm for the RP2040 chip, used in the Raspberry Pi Pico board. 
+This is a flash algorithm for the RP2040 and RP2350 chips, used in the Raspberry Pi Pico board.
 It implements the CMSIS-Pack ABI, so it's compatible with any tools that use it, including probe-rs.
 
 ## Dependencies
@@ -32,7 +32,7 @@ flash-algo$ ./build.sh
 The `algo` module contains the FlashAlgo trait, and an `algo!` macro to generate
 the glue functions for a given struct implementing it. This is generic for all chips, so feel free to reuse it!
 
-`main.rs` has the actual implementation for RP2040.
+`main.rs` has the actual implementation for RP2040 and RP2350.
 
 ## License
 

Diff for: src/main.rs

@@ -3,23 +3,112 @@
 
 use flash_algorithm::*;
 
-fn find_func<T>(tag: [u8; 2]) -> Option<T> {
-    let tag = u16::from_le_bytes(tag) as u32;
+extern "C" {
+    /// Enables the redundancy coprocessor (RCP)
+    ///
+    /// If the RCP is already initialized, `init_rcp` will skip initialization
+    /// as initializing it twice will cause a fault.
+    fn init_rcp();
+}
+
+// Implementation adapted from the PicoSDK's crt0.S.
+core::arch::global_asm!(
+    r#"
+    .syntax unified
+    .cpu cortex-m33
+    .thumb
+    .global init_rcp
+    init_rcp:
+        // Enable the RCP.  To save space, it is assumed that no other
+        // coprocessors are enabled.
+        ldr r0, =0xe0000000 + 0x0000ed88  // PPB_BASE + M33_CPACR_OFFSET
+        movs r1, 0x0000c000 // CPACR_CP7_BITS
+        str r1, [r0]
+
+        // Check that to see if the RCP is already initialized.
+        //
+        // Since this check requires passing `r15` to `mrc` and the inline
+        // assembler will not allow this, we hard code the instruction here:
+        //     `mrc p7, #1, r15, c0, c0, #0`
+        .byte 0x30
+        .byte 0xee
+        .byte 0x10
+        .byte 0xf7
+
+        // Skip initialization if already initialized.
+        bmi 2f
+
+        // Initialize the RCP.
+        mcrr p7, #8, r0, r0, c0
+        mcrr p7, #8, r0, r0, c1
+
+        // Signal other core.
+        sev
+
+        2:
+        bx lr
+    "#,
+);
+
+unsafe fn lookup_func_rp2040(tag: u32) -> usize {
     type RomTableLookupFn = unsafe extern "C" fn(table: *const u16, code: u32) -> usize;
-    /// This location in flash holds a 16-bit truncated pointer for the ROM lookup function
+
+    /// This location in ROM holds a 16-bit truncated pointer for the ROM lookup function for
+    /// RP2040 ROMs.
     const ROM_TABLE_LOOKUP_PTR: *const u16 = 0x0000_0018 as _;
-    /// This location in flash holds a 16-bit truncated pointer for the ROM function table
+
+    /// This location in ROM holds a 16-bit truncated pointer for the ROM function table
     /// (there's also a ROM data table which we don't need)
     const FUNC_TABLE: *const u16 = 0x0000_0014 as _;
+
+    let lookup_func = ROM_TABLE_LOOKUP_PTR.read() as usize;
+    let lookup_func: RomTableLookupFn = core::mem::transmute(lookup_func);
+    let table = FUNC_TABLE.read() as usize;
+    lookup_func(table as *const u16, tag)
+}
+
+unsafe fn lookup_func_235x(tag: u32) -> usize {
+    type RomTableLookupFn = unsafe extern "C" fn(code: u32, mask: u32) -> usize;
+
+    /// This location in ROM holds a 16-bit truncated pointer for the ROM lookup function for
+    /// RP235x ROMs.
+    const ROM_TABLE_LOOKUP_PTR: *const u16 = 0x0000_0016 as _;
+
+    /// The flash-algo needs to run in secure mode so we need too look up
+    /// functions in that context
+    const RT_FLAG_FUNC_ARM_SEC: u32 = 0x0004;
+
+    // The RCP (redundancy coprocessor) must be enabled in order to call ROM functions.
+    init_rcp();
+
+    let lookup_func = ROM_TABLE_LOOKUP_PTR.read() as usize;
+    let lookup_func: RomTableLookupFn = core::mem::transmute(lookup_func);
+    lookup_func(tag, RT_FLAG_FUNC_ARM_SEC)
+}
+
+fn find_func<T>(tag: [u8; 2]) -> Result<T, ErrorCode> {
+    let tag = u16::from_le_bytes(tag) as u32;
+
+    /// This location in ROM holds a 3 byte magic value that confirms the validity of the
+    /// ROM as well as identifying different interfaces for the RP2040 and RP235x.
+    const BOOTROM_MAGIC: *const [u8; 3] = 0x0000_0010 as _;
+
+    /// Magic value for RP2040 ROMs.
+    const RP2040_BOOTROM_MAGIC: &[u8; 3] = b"Mu\x01";
+
+    /// Magic value for RP235X ROMs.
+    const RP235X_BOOTROM_MAGIC: &[u8; 3] = b"Mu\x02";
+
     unsafe {
-        let lookup_func = ROM_TABLE_LOOKUP_PTR.read() as usize;
-        let lookup_func: RomTableLookupFn = core::mem::transmute(lookup_func);
-        let table = FUNC_TABLE.read() as usize;
-        let result = lookup_func(table as *const u16, tag);
+        let result = match &*BOOTROM_MAGIC {
+            RP2040_BOOTROM_MAGIC => lookup_func_rp2040(tag),
+            RP235X_BOOTROM_MAGIC => lookup_func_235x(tag),
+            _ => return Err(ErrorCode::new(0x1000_0000 | tag).unwrap()),
+        };
         if result == 0 {
-            return None;
+            return Err(ErrorCode::new(0x2000_0000 | tag).unwrap());
         }
-        Some(core::mem::transmute_copy(&result))
+        Ok(core::mem::transmute_copy(&result))
     }
 }
 
@@ -33,8 +122,8 @@ struct ROMFuncs {
 }
 
 impl ROMFuncs {
-    fn load() -> Option<Self> {
-        Some(ROMFuncs {
+    fn load() -> Result<Self, ErrorCode> {
+        Ok(ROMFuncs {
             connect_internal_flash: find_func(*b"IF")?,
             flash_exit_xip: find_func(*b"EX")?,
             flash_range_erase: find_func(*b"RE")?,
@@ -45,11 +134,11 @@ impl ROMFuncs {
     }
 }
 
-struct RP2040Algo {
+struct RP2Algo {
     funcs: ROMFuncs,
 }
 
-algorithm!(RP2040Algo, {
+algorithm!(RP2Algo, {
     flash_address: 0x1000_0000,
     flash_size: 0x0100_0000,
     page_size: 0x100,
@@ -64,11 +153,9 @@ const BLOCK_SIZE: u32 = 65536;
 const SECTOR_SIZE: u32 = 4096;
 const BLOCK_ERASE_CMD: u8 = 0xd8;
 
-impl FlashAlgorithm for RP2040Algo {
+impl FlashAlgorithm for RP2Algo {
     fn new(_address: u32, _clock: u32, _function: Function) -> Result<Self, ErrorCode> {
-        let Some(funcs) = ROMFuncs::load() else {
-            return Err(ErrorCode::new(1).unwrap());
-        };
+        let funcs = ROMFuncs::load()?;
         (funcs.connect_internal_flash)();
         (funcs.flash_exit_xip)();
         Ok(Self { funcs })
@@ -94,7 +181,7 @@ impl FlashAlgorithm for RP2040Algo {
     }
 }
 
-impl Drop for RP2040Algo {
+impl Drop for RP2Algo {
     fn drop(&mut self) {
         (self.funcs.flash_flush_cache)();
         (self.funcs.flash_enter_cmd_xip)();