add timer_src_clk_sys feature to support running RP2350x timer at s…

embassy-rp/Cargo.toml

@@ -42,7 +42,8 @@ critical-section-impl = ["critical-section/restore-state-u8"]
 unstable-pac = []
 
 ## Enable the timer for use with `embassy-time` with a 1MHz tick rate.
-time-driver = ["dep:embassy-time-driver", "embassy-time-driver?/tick-hz-1_000_000", "dep:embassy-time-queue-utils"]
+#time-driver = ["dep:embassy-time-driver", "embassy-time-driver?/tick-hz-1_000_000", "dep:embassy-time-queue-utils"]
+time-driver = ["dep:embassy-time-driver", "dep:embassy-time-queue-utils"]
 
 ## Enable ROM function cache. This will store the address of a ROM function when first used, improving performance of subsequent calls.
 rom-func-cache = []
@@ -122,7 +123,15 @@ _rp235x = ["rp-pac/rp235x"]
 rp235xa = ["_rp235x"]
 ## Configure the hal for use with the rp235xB
 rp235xb = ["_rp235x"]
-
+## Add a feature which configures `embassy-time-driver` with 150MHz `tick`s.  This is an indication
+## by the upstream crate that the RP2350's `TIMER`s are configured with the system clock as their
+## source (typically 150MHz), instead of the usual 1MHz.
+## Compilation flag checks in `lib.rs` ensure this feature is only used together with `_rp235x`
+timer-src-clk-sys = [
+    "dep:embassy-time-driver",
+    "embassy-time-driver?/tick-hz-150_000_000",
+    "dep:embassy-time-queue-utils",
+]
 # hack around cortex-m peripherals being wrong when running tests.
 _test = []
 

embassy-rp/src/lib.rs

@@ -6,6 +6,19 @@
 //! ## Feature flags
 #![doc = document_features::document_features!(feature_label = r#"<span class="stab portability"><code>{feature}</code></span>"#)]
 
+//! ## Compatible feature flags
+// `timer-src-clk-sys` only makes sense on RP235x silicon.
+#[cfg(all(feature = "timer-src-clk-sys", not(feature = "_rp235x"),))]
+compile_error!(
+    "`embassy-rp` feature `timer-src-clk-sys` requires an `rp235x` feature (either `rp235xa` or \
+    `rp235xb`) to be enabled."
+);
+
+// // Prevent users from selecting both timer drivers (although this condition causes a redefinition
+// // error in our deps before this code can halt the compilation with an explanation...)
+// #[cfg(all(feature = "timer-src-clk-sys", feature = "time-driver"))]
+// compile_error!("Enable only one of `time-driver` or `timer-src-clk-sys`.");
+
 // This mod MUST go first, so that the others see its macros.
 pub(crate) mod fmt;
 

embassy-rp/src/time_driver.rs

@@ -10,6 +10,8 @@ use embassy_time_queue_utils::Queue;
 use pac::TIMER;
 #[cfg(feature = "_rp235x")]
 use pac::TIMER0 as TIMER;
+#[cfg(all(feature = "_rp235x", feature = "timer-src-clk-sys"))]
+use rp_pac::timer::vals::ClkSys;
 
 use crate::interrupt::InterruptExt;
 use crate::{interrupt, pac};
@@ -129,6 +131,16 @@ pub unsafe fn init() {
     {
         interrupt::TIMER0_IRQ_0.enable();
     }
+    #[cfg(all(feature = "_rp235x", feature = "timer-src-clk-sys"))]
+    {
+        // The PAC currently only defines `TIMER0` as `TIMER` even though the RP2350 also has
+        // `TIMER1`.
+        let timer_0 = TIMER;
+        // Switch `SOURCE` to `CLK_SYS` (instead of 1 µs tick)
+        timer_0.source().write(|w| w.set_clk_sys(ClkSys::CLK_SYS));
+        // Lock configuration--`TIMER0` now read-only (until reset)
+        timer_0.locked().write(|w| w.set_locked(true));
+    }
 }
 
 #[cfg(all(feature = "rt", feature = "rp2040"))]

embassy-rp/src/usb.rs

@@ -655,35 +655,33 @@ impl<'d, T: Instance> driver::ControlPipe for ControlPipe<'d, T> {
     }
 
     async fn setup(&mut self) -> [u8; 8] {
-        loop {
-            trace!("SETUP read waiting");
-            let regs = T::regs();
-            regs.inte().write_set(|w| w.set_setup_req(true));
+        trace!("SETUP read waiting");
+        let regs = T::regs();
+        regs.inte().write_set(|w| w.set_setup_req(true));
 
-            poll_fn(|cx| {
-                EP_OUT_WAKERS[0].register(cx.waker());
-                let regs = T::regs();
-                if regs.sie_status().read().setup_rec() {
-                    Poll::Ready(())
-                } else {
-                    Poll::Pending
-                }
-            })
-            .await;
+        poll_fn(|cx| {
+            EP_OUT_WAKERS[0].register(cx.waker());
+            let regs = T::regs();
+            if regs.sie_status().read().setup_rec() {
+                Poll::Ready(())
+            } else {
+                Poll::Pending
+            }
+        })
+        .await;
 
-            let mut buf = [0; 8];
-            EndpointBuffer::<T>::new(0, 8).read(&mut buf);
+        let mut buf = [0; 8];
+        EndpointBuffer::<T>::new(0, 8).read(&mut buf);
 
-            let regs = T::regs();
-            regs.sie_status().write(|w| w.set_setup_rec(true));
+        let regs = T::regs();
+        regs.sie_status().write(|w| w.set_setup_rec(true));
 
-            // set PID to 0, so (after toggling) first DATA is PID 1
-            T::dpram().ep_in_buffer_control(0).write(|w| w.set_pid(0, false));
-            T::dpram().ep_out_buffer_control(0).write(|w| w.set_pid(0, false));
+        // set PID to 0, so (after toggling) first DATA is PID 1
+        T::dpram().ep_in_buffer_control(0).write(|w| w.set_pid(0, false));
+        T::dpram().ep_out_buffer_control(0).write(|w| w.set_pid(0, false));
 
-            trace!("SETUP read ok");
-            return buf;
-        }
+        trace!("SETUP read ok");
+        return buf;
     }
 
     async fn data_out(&mut self, buf: &mut [u8], first: bool, last: bool) -> Result<usize, EndpointError> {