feat(reboot): add system reboot commands

README.md

@@ -74,10 +74,11 @@ When connected the emberOne usbserial firmware will create two serial ports. Usu
 3. command bus
 	- always 0x00 
 4. command page
-	- I2C:  0x05
-	- GPIO: 0x06
-	- ADC:  0x07
-	- LED:  0x08 
+	- I2C:    0x05
+	- GPIO:   0x06
+	- ADC:    0x07
+	- LED:    0x08
+	- System: 0x09
 5. command 
 	- varies by command page. See below
 6. data
@@ -151,3 +152,23 @@ Data:
 Example:
 
 - Set LED Magenta: `09 00 00 00 08 10 FF 00 FF`
+
+**System**
+
+Commands require a magic payload to guard against accidental
+reboot from line noise or a framing desync. No response is
+sent; the host detects success by observing USB re-enumeration.
+
+Commands:
+
+- Reboot: 0x01 (magic: `DE AD BE EF`)
+- Reboot to bootloader: 0x02 (magic: `B0 07 10 AD`)
+
+Data:
+
+- [magic (4 bytes)]
+
+Examples:
+
+- Reboot: `0A 00 00 00 09 01 DE AD BE EF`
+- Reboot to bootloader: `0A 00 00 00 09 02 B0 07 10 AD`

src/control/mod.rs

@@ -22,6 +22,8 @@ const ADC_COMMAND: u8 = 7;
 pub mod led;
 const LED_COMMAND: u8 = 8;
 
+pub mod system;
+const SYSTEM_COMMAND: u8 = 9;
 
 #[derive(defmt::Format)]
 struct Command {
@@ -36,6 +38,7 @@ enum CommandInner {
     Gpio(gpio::Command),
     Adc(adc::Command),
     Led(led::Command),
+    System(system::Command),
     Error(CommandError),
 }
 
@@ -63,6 +66,11 @@ impl Command {
                 bus: buf[1],
                 inner: CommandInner::Led(led::Command::from_bytes(&buf[3..])?),
             }),
+            SYSTEM_COMMAND => Ok(Self {
+                id,
+                bus: buf[1],
+                inner: CommandInner::System(system::Command::from_bytes(&buf[3..])?),
+            }),
             _ => Err(CommandError::Invalid),
         }
     }
@@ -126,6 +134,7 @@ impl Controller {
                 CommandInner::Gpio(cmd) => cmd.handle(self).await,
                 CommandInner::Adc(cmd) => cmd.handle(self).await,
                 CommandInner::Led(cmd) => cmd.handle(self).await,
+                CommandInner::System(cmd) => cmd.handle(self).await,
                 CommandInner::Error(err) => Err(err),
             };
 

src/control/system.rs

@@ -0,0 +1,46 @@
+use defmt::{info, panic};
+use heapless::Vec;
+
+use super::CommandError;
+
+// Commands require a magic payload to guard against accidental reboot
+// from line noise or a framing desync.
+const REBOOT_MAGIC: [u8; 4] = [0xDE, 0xAD, 0xBE, 0xEF];
+const REBOOT_TO_BOOTLOADER_MAGIC: [u8; 4] = [0xB0, 0x07, 0x10, 0xAD];
+
+#[derive(defmt::Format)]
+pub enum Command {
+    Reboot,
+    RebootToBootloader,
+}
+
+impl Command {
+    pub fn from_bytes(buf: &[u8]) -> Result<Self, CommandError> {
+        match buf {
+            [0x01, rest @ ..] if rest == REBOOT_MAGIC => Ok(Self::Reboot),
+            [0x02, rest @ ..] if rest == REBOOT_TO_BOOTLOADER_MAGIC => {
+                Ok(Self::RebootToBootloader)
+            }
+            _ => Err(CommandError::Invalid),
+        }
+    }
+}
+
+impl super::ControllerCommand for Command {
+    async fn handle(
+        &self,
+        _controller: &mut super::Controller,
+    ) -> Result<Vec<u8, 256>, CommandError> {
+        match self {
+            Command::Reboot => {
+                info!("System: rebooting");
+                cortex_m::peripheral::SCB::sys_reset()
+            }
+            Command::RebootToBootloader => {
+                info!("System: rebooting to bootloader");
+                embassy_rp::rom_data::reset_to_usb_boot(0, 0);
+                panic!("reset_to_usb_boot returned");
+            }
+        }
+    }
+}