rp: add run-from-ram feature.

2 files changed, 9 insertions, 1 deletions

diff --git a/embassy-rp/Cargo.toml b/embassy-rp/Cargo.toml
index 5f08c7f33..ddada655b 100644
--- a/embassy-rp/Cargo.toml
+++ b/embassy-rp/Cargo.toml
@@ -41,6 +41,11 @@ boot2-ram-memcpy = []
 boot2-w25q080 = []
 boot2-w25x10cl = []
 
+# Indicate code is running from RAM.
+# Set this if all code is in RAM, and the cores never access memory-mapped flash memory through XIP.
+# This allows the flash driver to not force pausing execution on both cores when doing flash operations.
+run-from-ram = []
+
 # Enable nightly-only features
 nightly = ["embassy-executor/nightly", "embedded-hal-1", "embedded-hal-async", "embassy-embedded-hal/nightly", "dep:embassy-usb-driver", "dep:embedded-io"]
 
diff --git a/embassy-rp/src/flash.rs b/embassy-rp/src/flash.rs
index 0372afb1e..5d928abad 100644
--- a/embassy-rp/src/flash.rs
+++ b/embassy-rp/src/flash.rs
@@ -10,7 +10,10 @@ use crate::pac;
 use crate::peripherals::FLASH;
 
 pub const FLASH_BASE: *const u32 = 0x10000000 as _;
-pub const USE_BOOT2: bool = true;
+
+// If running from RAM, we might have no boot2. Use bootrom `flash_enter_cmd_xip` instead.
+// TODO: when run-from-ram is set, completely skip the "pause cores and jumpp to RAM" dance.
+pub const USE_BOOT2: bool = !cfg!(feature = "run-from-ram");
 
 // **NOTE**:
 //