rp: relocate programs implicitly during load

this removed the RelocatedProgram construction step from pio uses.
there's not all that much to be said for the extra step because the
origin can be set on the input program itself, and the remaining
information exposed by RelocatedProgram can be exposed from
LoadedProgram instead (even though it's already available on the pio_asm
programs, albeit perhaps less convenient). we do lose access to the
relocated instruction iterator, but we also cannot think of anything
this iterator would actually be useful for outside of program loading.

1 files changed, 10 insertions, 31 deletions

diff --git a/examples/rp/src/bin/pio_uart.rs b/examples/rp/src/bin/pio_uart.rs
index ca1c7f394..5fddbe292 100644
--- a/examples/rp/src/bin/pio_uart.rs
+++ b/examples/rp/src/bin/pio_uart.rs
@@ -222,8 +222,8 @@ mod uart {
                 mut common, sm0, sm1, ..
             } = Pio::new(pio, Irqs);
 
-            let (tx, origin) = PioUartTx::new(&mut common, sm0, tx_pin, baud, None);
-            let (rx, _) = PioUartRx::new(&mut common, sm1, rx_pin, baud, Some(origin));
+            let tx = PioUartTx::new(&mut common, sm0, tx_pin, baud);
+            let rx = PioUartRx::new(&mut common, sm1, rx_pin, baud);
 
             PioUart { tx, rx }
         }
@@ -240,7 +240,6 @@ mod uart_tx {
     use embassy_rp::gpio::Level;
     use embassy_rp::peripherals::PIO0;
     use embassy_rp::pio::{Common, Config, Direction, FifoJoin, PioPin, ShiftDirection, StateMachine};
-    use embassy_rp::relocate::RelocatedProgram;
     use embedded_io::asynch::Write;
     use embedded_io::Io;
     use fixed::traits::ToFixed;
@@ -256,9 +255,8 @@ mod uart_tx {
             mut sm_tx: StateMachine<'a, PIO0, 0>,
             tx_pin: impl PioPin,
             baud: u64,
-            origin: Option<u8>,
-        ) -> (Self, u8) {
-            let mut prg = pio_proc::pio_asm!(
+        ) -> Self {
+            let prg = pio_proc::pio_asm!(
                 r#"
                 .side_set 1 opt
 
@@ -272,17 +270,14 @@ mod uart_tx {
                     jmp x-- bitloop   [6]  ; Each loop iteration is 8 cycles.
             "#
             );
-            prg.program.origin = origin;
             let tx_pin = common.make_pio_pin(tx_pin);
             sm_tx.set_pins(Level::High, &[&tx_pin]);
             sm_tx.set_pin_dirs(Direction::Out, &[&tx_pin]);
 
-            let relocated = RelocatedProgram::new(&prg.program);
-
             let mut cfg = Config::default();
 
             cfg.set_out_pins(&[&tx_pin]);
-            cfg.use_program(&common.load_program(&relocated), &[&tx_pin]);
+            cfg.use_program(&common.load_program(&prg.program), &[&tx_pin]);
             cfg.shift_out.auto_fill = false;
             cfg.shift_out.direction = ShiftDirection::Right;
             cfg.fifo_join = FifoJoin::TxOnly;
@@ -290,18 +285,7 @@ mod uart_tx {
             sm_tx.set_config(&cfg);
             sm_tx.set_enable(true);
 
-            // The 4 state machines of the PIO each have their own program counter that starts taking
-            // instructions at an offset (origin) of the 32 instruction "space" the PIO device has.
-            // It is up to the programmer to sort out where to place these instructions.
-            // From the pio_asm! macro you get a ProgramWithDefines which has a field .program.origin
-            // which takes an Option<u8>.
-            //
-            // When you load more than one RelocatedProgram into the PIO,
-            // you load your first program at origin = 0.
-            // The RelocatedProgram has .code().count() which returns a usize,
-            // for which you can then use as your next program's origin.
-            let offset = relocated.code().count() as u8 + origin.unwrap_or_default();
-            (Self { sm_tx }, offset)
+            Self { sm_tx }
         }
 
         pub async fn write_u8(&mut self, data: u8) {
@@ -329,7 +313,6 @@ mod uart_rx {
     use embassy_rp::gpio::Level;
     use embassy_rp::peripherals::PIO0;
     use embassy_rp::pio::{Common, Config, Direction, FifoJoin, PioPin, ShiftDirection, StateMachine};
-    use embassy_rp::relocate::RelocatedProgram;
     use embedded_io::asynch::Read;
     use embedded_io::Io;
     use fixed::traits::ToFixed;
@@ -345,9 +328,8 @@ mod uart_rx {
             mut sm_rx: StateMachine<'a, PIO0, 1>,
             rx_pin: impl PioPin,
             baud: u64,
-            origin: Option<u8>,
-        ) -> (Self, u8) {
-            let mut prg = pio_proc::pio_asm!(
+        ) -> Self {
+            let prg = pio_proc::pio_asm!(
                 r#"
                 ; Slightly more fleshed-out 8n1 UART receiver which handles framing errors and
                 ; break conditions more gracefully.
@@ -369,10 +351,8 @@ mod uart_rx {
                     push                ; important in case the TX clock is slightly too fast.
             "#
             );
-            prg.program.origin = origin;
-            let relocated = RelocatedProgram::new(&prg.program);
             let mut cfg = Config::default();
-            cfg.use_program(&common.load_program(&relocated), &[]);
+            cfg.use_program(&common.load_program(&prg.program), &[]);
 
             let rx_pin = common.make_pio_pin(rx_pin);
             sm_rx.set_pins(Level::High, &[&rx_pin]);
@@ -387,8 +367,7 @@ mod uart_rx {
             sm_rx.set_config(&cfg);
             sm_rx.set_enable(true);
 
-            let offset = relocated.code().count() as u8 + origin.unwrap_or_default();
-            (Self { sm_rx }, offset)
+            Self { sm_rx }
         }
 
         pub async fn read_u8(&mut self) -> u8 {