Add support for STM32G0

embassy-stm32/src/rcc/g0/mod.rs

@@ -0,0 +1,190 @@
+pub use super::types::*;
+use crate::pac;
+use crate::peripherals::{self, RCC};
+use crate::rcc::{get_freqs, set_freqs, Clocks};
+use crate::time::Hertz;
+use crate::time::U32Ext;
+use core::marker::PhantomData;
+use embassy::util::Unborrow;
+use embassy_hal_common::unborrow;
+
+/// HSI speed
+pub const HSI_FREQ: u32 = 16_000_000;
+
+/// LSI speed
+pub const LSI_FREQ: u32 = 32_000;
+
+/// System clock mux source
+#[derive(Clone, Copy)]
+pub enum ClockSrc {
+    HSE(Hertz),
+    HSI16,
+    LSI,
+}
+
+impl Into<u8> for APBPrescaler {
+    fn into(self) -> u8 {
+        match self {
+            APBPrescaler::NotDivided => 1,
+            APBPrescaler::Div2 => 0x04,
+            APBPrescaler::Div4 => 0x05,
+            APBPrescaler::Div8 => 0x06,
+            APBPrescaler::Div16 => 0x07,
+        }
+    }
+}
+
+impl Into<u8> for AHBPrescaler {
+    fn into(self) -> u8 {
+        match self {
+            AHBPrescaler::NotDivided => 1,
+            AHBPrescaler::Div2 => 0x08,
+            AHBPrescaler::Div4 => 0x09,
+            AHBPrescaler::Div8 => 0x0a,
+            AHBPrescaler::Div16 => 0x0b,
+            AHBPrescaler::Div64 => 0x0c,
+            AHBPrescaler::Div128 => 0x0d,
+            AHBPrescaler::Div256 => 0x0e,
+            AHBPrescaler::Div512 => 0x0f,
+        }
+    }
+}
+
+/// Clocks configutation
+pub struct Config {
+    mux: ClockSrc,
+    ahb_pre: AHBPrescaler,
+    apb_pre: APBPrescaler,
+}
+
+impl Default for Config {
+    #[inline]
+    fn default() -> Config {
+        Config {
+            mux: ClockSrc::HSI16,
+            ahb_pre: AHBPrescaler::NotDivided,
+            apb_pre: APBPrescaler::NotDivided,
+        }
+    }
+}
+
+impl Config {
+    #[inline]
+    pub fn clock_src(mut self, mux: ClockSrc) -> Self {
+        self.mux = mux;
+        self
+    }
+
+    #[inline]
+    pub fn ahb_pre(mut self, pre: AHBPrescaler) -> Self {
+        self.ahb_pre = pre;
+        self
+    }
+
+    #[inline]
+    pub fn apb_pre(mut self, pre: APBPrescaler) -> Self {
+        self.apb_pre = pre;
+        self
+    }
+}
+
+/// RCC peripheral
+pub struct Rcc<'d> {
+    _rb: peripherals::RCC,
+    phantom: PhantomData<&'d mut peripherals::RCC>,
+}
+
+impl<'d> Rcc<'d> {
+    pub fn new(rcc: impl Unborrow<Target = peripherals::RCC> + 'd) -> Self {
+        unborrow!(rcc);
+        Self {
+            _rb: rcc,
+            phantom: PhantomData,
+        }
+    }
+
+    // Safety: RCC init must have been called
+    pub fn clocks(&self) -> &'static Clocks {
+        unsafe { get_freqs() }
+    }
+}
+
+/// Extension trait that freezes the `RCC` peripheral with provided clocks configuration
+pub trait RccExt {
+    fn freeze(self, config: Config) -> Clocks;
+}
+
+impl RccExt for RCC {
+    #[inline]
+    fn freeze(self, cfgr: Config) -> Clocks {
+        let rcc = pac::RCC;
+        let (sys_clk, sw) = match cfgr.mux {
+            ClockSrc::HSI16 => {
+                // Enable HSI16
+                unsafe {
+                    rcc.cr().write(|w| w.set_hsion(true));
+                    while !rcc.cr().read().hsirdy() {}
+                }
+
+                (HSI_FREQ, 0x00)
+            }
+            ClockSrc::HSE(freq) => {
+                // Enable HSE
+                unsafe {
+                    rcc.cr().write(|w| w.set_hseon(true));
+                    while !rcc.cr().read().hserdy() {}
+                }
+
+                (freq.0, 0x01)
+            }
+            ClockSrc::LSI => {
+                // Enable LSI
+                unsafe {
+                    rcc.csr().write(|w| w.set_lsion(true));
+                    while !rcc.csr().read().lsirdy() {}
+                }
+                (LSI_FREQ, 0x03)
+            }
+        };
+
+        unsafe {
+            rcc.cfgr().modify(|w| {
+                w.set_sw(sw.into());
+                w.set_hpre(cfgr.ahb_pre.into());
+                w.set_ppre(cfgr.apb_pre.into());
+            });
+        }
+
+        let ahb_freq: u32 = match cfgr.ahb_pre {
+            AHBPrescaler::NotDivided => sys_clk,
+            pre => {
+                let pre: u8 = pre.into();
+                let pre = 1 << (pre as u32 - 7);
+                sys_clk / pre
+            }
+        };
+
+        let (apb_freq, apb_tim_freq) = match cfgr.apb_pre {
+            APBPrescaler::NotDivided => (ahb_freq, ahb_freq),
+            pre => {
+                let pre: u8 = pre.into();
+                let pre: u8 = 1 << (pre - 3);
+                let freq = ahb_freq / pre as u32;
+                (freq, freq * 2)
+            }
+        };
+
+        Clocks {
+            sys: sys_clk.hz(),
+            ahb: ahb_freq.hz(),
+            apb: apb_freq.hz(),
+            apb_tim: apb_tim_freq.hz(),
+        }
+    }
+}
+
+pub unsafe fn init(config: Config) {
+    let r = <peripherals::RCC as embassy::util::Steal>::steal();
+    let clocks = r.freeze(config);
+    set_freqs(clocks);
+}

embassy-stm32/src/rcc/mod.rs

@@ -8,15 +8,26 @@ mod types;
 #[derive(Clone, Copy)]
 pub struct Clocks {
     pub sys: Hertz,
+
+    #[cfg(rcc_g0)]
+    pub apb: Hertz,
+    #[cfg(rcc_g0)]
+    pub apb_tim: Hertz,
+
+    #[cfg(not(rcc_g0))]
     pub apb1: Hertz,
+    #[cfg(not(rcc_g0))]
+    pub apb1_tim: Hertz,
+
+    #[cfg(not(rcc_g0))]
     pub apb2: Hertz,
+    #[cfg(not(rcc_g0))]
+    pub apb2_tim: Hertz,
+
     #[cfg(rcc_wl5)]
     pub apb3: Hertz,
 
-    pub apb1_tim: Hertz,
-    pub apb2_tim: Hertz,
-
-    #[cfg(any(rcc_l0, rcc_f0, rcc_f0x0))]
+    #[cfg(any(rcc_l0, rcc_f0, rcc_f0x0, rcc_g0))]
     pub ahb: Hertz,
 
     #[cfg(any(rcc_l4, rcc_f4, rcc_h7, rcc_wb, rcc_wl5))]
@@ -77,6 +88,9 @@ cfg_if::cfg_if! {
     } else if #[cfg(any(rcc_f0, rcc_f0x0))] {
         mod f0;
         pub use f0::*;
+    } else if #[cfg(any(rcc_g0))] {
+        mod g0;
+        pub use g0::*;
     }
 }