Enable clock by default for stm32l0

Modify init function to return a Clock instance defined by a per-chip
SystemClock type and use this in macro setup

A proof of concept implementation for STM32 L0 chips.

This allows using embassy::main macros for STM32 devices that have the
clock setup logic.
This commit is contained in:
Ulf Lilleengen 2021-05-25 17:09:01 +02:00
parent a126e17fb2
commit c501b162fc
7 changed files with 614 additions and 25 deletions

View file

@ -7,20 +7,17 @@ pub fn generate(embassy_prefix: &ModulePrefix, config: syn::Expr) -> TokenStream
let embassy_stm32_path = embassy_prefix.append("embassy_stm32").path();
quote!(
use #embassy_stm32_path::{clock::Clock};
use #embassy_stm32_path::{interrupt, peripherals, clock::Clock, time::Hertz};
let p = #embassy_stm32_path::init(#config);
let (p, mut c) = #embassy_stm32_path::init(#config);
/*
let mut rtc = #embass::RTC::new(unsafe { <peripherals::TIM2 as #embassy_path::util::Steal>::steal() }, interrupt::take!(TIM2));
let rtc = unsafe { make_static(&mut rtc) };
rtc.start();
let mut alarm = rtc.alarm0();
let clock = unsafe { make_static(&mut c) };
clock.start();
unsafe { #embassy_path::time::set_clock(rtc) };
let mut alarm = clock.alarm1();
unsafe { #embassy_path::time::set_clock(clock) };
let alarm = unsafe { make_static(&mut alarm) };
executor.set_alarm(alarm);
*/
)
}

View file

@ -350,6 +350,13 @@ pub fn main(args: TokenStream, item: TokenStream) -> TokenStream {
#[cortex_m_rt::entry]
fn main() -> ! {
rtt_init_print!();
unsafe {
log::set_logger_racy(&LOGGER).unwrap();
}
log::set_max_level(log::LevelFilter::Trace);
log::info!("Hello World!");
unsafe fn make_static<T>(t: &mut T) -> &'static mut T {
::core::mem::transmute(t)
}

View file

@ -59,6 +59,8 @@ const ALARM_COUNT: usize = 3;
pub struct Clock<T: Instance> {
_inner: T,
irq: T::Interrupt,
/// Clock frequency
frequency: Hertz,
/// Number of 2^23 periods elapsed since boot.
period: AtomicU32,
/// Timestamp at which to fire alarm. u64::MAX if no alarm is scheduled.
@ -66,22 +68,23 @@ pub struct Clock<T: Instance> {
}
impl<T: Instance> Clock<T> {
pub fn new(peripheral: T, irq: T::Interrupt) -> Self {
pub fn new(peripheral: T, irq: T::Interrupt, frequency: Hertz) -> Self {
Self {
_inner: peripheral,
irq,
frequency,
period: AtomicU32::new(0),
alarms: Mutex::new([AlarmState::new(), AlarmState::new(), AlarmState::new()]),
}
}
pub fn start(&'static self, timer_freq: Hertz) {
pub fn start(&'static self) {
let inner = T::inner();
// NOTE(unsafe) Critical section to use the unsafe methods
critical_section::with(|_| {
unsafe {
inner.prepare(timer_freq);
inner.prepare(self.frequency);
}
self.irq.set_handler_context(self as *const _ as *mut _);

View file

@ -36,6 +36,7 @@ pub mod time;
pub use embassy_macros::interrupt;
pub use pac::{interrupt, peripherals, Peripherals};
pub use rcc::SystemClock;
// workaround for svd2rust-generated code using `use crate::generic::*;`
pub(crate) use pac::regs::generic;
@ -45,6 +46,12 @@ pub struct Config {
rcc: rcc::Config,
}
impl Config {
pub fn new(rcc: rcc::Config) -> Self {
Self { rcc }
}
}
impl Default for Config {
fn default() -> Self {
Self {
@ -54,14 +61,12 @@ impl Default for Config {
}
/// Initialize embassy.
pub fn init(config: Config) -> Peripherals {
pub fn init(config: Config) -> (Peripherals, SystemClock) {
let p = Peripherals::take();
unsafe {
dma::init();
pac::init_exti();
rcc::init(config.rcc);
(p, rcc::init(config.rcc))
}
p
}

View file

@ -528,6 +528,6 @@ impl<'d> Rcc<'d> {
}
}
pub unsafe fn init(config: Config) {
// TODO
}
pub type SystemClock = ();
pub unsafe fn init(_config: Config) -> SystemClock {}

View file

@ -1,11 +1,574 @@
use crate::clock::Clock;
use crate::interrupt;
use crate::pac;
use embassy::util::Steal;
use pac::rcc::{self, vals};
use crate::pac::peripherals::{self, TIM2};
use crate::time::Hertz;
use crate::time::U32Ext;
use pac::rcc::vals;
use vals::{Hpre, Lptimen, Msirange, Plldiv, Pllmul, Pllon, Pllsrc, Ppre, Sw};
#[derive(Default)]
pub struct Config {}
/// Most of clock setup is copied from stm32l0xx-hal, and adopted to the generated PAC,
/// and with the addition of the init function to configure a system clock.
pub unsafe fn init(config: Config) {
/// System clock mux source
#[derive(Clone, Copy)]
pub enum ClockSrc {
MSI(MSIRange),
PLL(PLLSource, PLLMul, PLLDiv),
HSE(Hertz),
HSI16,
}
/// MSI Clock Range
///
/// These ranges control the frequency of the MSI. Internally, these ranges map
/// to the `MSIRANGE` bits in the `RCC_ICSCR` register.
#[derive(Clone, Copy)]
pub enum MSIRange {
/// Around 65.536 kHz
Range0,
/// Around 131.072 kHz
Range1,
/// Around 262.144 kHz
Range2,
/// Around 524.288 kHz
Range3,
/// Around 1.048 MHz
Range4,
/// Around 2.097 MHz (reset value)
Range5,
/// Around 4.194 MHz
Range6,
}
impl Default for MSIRange {
fn default() -> MSIRange {
MSIRange::Range5
}
}
/// PLL divider
#[derive(Clone, Copy)]
pub enum PLLDiv {
Div2,
Div3,
Div4,
}
/// PLL multiplier
#[derive(Clone, Copy)]
pub enum PLLMul {
Mul3,
Mul4,
Mul6,
Mul8,
Mul12,
Mul16,
Mul24,
Mul32,
Mul48,
}
/// AHB prescaler
#[derive(Clone, Copy)]
pub enum AHBPrescaler {
NotDivided,
Div2,
Div4,
Div8,
Div16,
Div64,
Div128,
Div256,
Div512,
}
/// APB prescaler
#[derive(Clone, Copy)]
pub enum APBPrescaler {
NotDivided,
Div2,
Div4,
Div8,
Div16,
}
/// PLL clock input source
#[derive(Clone, Copy)]
pub enum PLLSource {
HSI16,
HSE(Hertz),
}
/// HSI speed
pub const HSI_FREQ: u32 = 16_000_000;
/// Clocks configutation
pub struct Config {
mux: ClockSrc,
ahb_pre: AHBPrescaler,
apb1_pre: APBPrescaler,
apb2_pre: APBPrescaler,
}
impl Default for Config {
#[inline]
fn default() -> Config {
Config {
mux: ClockSrc::MSI(MSIRange::default()),
ahb_pre: AHBPrescaler::NotDivided,
apb1_pre: APBPrescaler::NotDivided,
apb2_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 apb1_pre(mut self, pre: APBPrescaler) -> Self {
self.apb1_pre = pre;
self
}
#[inline]
pub fn apb2_pre(mut self, pre: APBPrescaler) -> Self {
self.apb2_pre = pre;
self
}
#[inline]
pub fn hsi16() -> Config {
Config {
mux: ClockSrc::HSI16,
ahb_pre: AHBPrescaler::NotDivided,
apb1_pre: APBPrescaler::NotDivided,
apb2_pre: APBPrescaler::NotDivided,
}
}
#[inline]
pub fn msi(range: MSIRange) -> Config {
Config {
mux: ClockSrc::MSI(range),
ahb_pre: AHBPrescaler::NotDivided,
apb1_pre: APBPrescaler::NotDivided,
apb2_pre: APBPrescaler::NotDivided,
}
}
#[inline]
pub fn pll(pll_src: PLLSource, pll_mul: PLLMul, pll_div: PLLDiv) -> Config {
Config {
mux: ClockSrc::PLL(pll_src, pll_mul, pll_div),
ahb_pre: AHBPrescaler::NotDivided,
apb1_pre: APBPrescaler::NotDivided,
apb2_pre: APBPrescaler::NotDivided,
}
}
#[inline]
pub fn hse<T>(freq: T) -> Config
where
T: Into<Hertz>,
{
Config {
mux: ClockSrc::HSE(freq.into()),
ahb_pre: AHBPrescaler::NotDivided,
apb1_pre: APBPrescaler::NotDivided,
apb2_pre: APBPrescaler::NotDivided,
}
}
}
/// RCC peripheral
pub struct Rcc {
clocks: Clocks,
rb: pac::rcc::Rcc,
}
/*
impl Rcc {
pub fn enable_lse(&mut self, _: &PWR) -> LSE {
self.rb.csr.modify(|_, w| {
// Enable LSE clock
w.lseon().set_bit()
});
while self.rb.csr.read().lserdy().bit_is_clear() {}
LSE(())
}
}
impl Rcc {
pub fn enable_hsi48(&mut self, syscfg: &mut SYSCFG, crs: CRS) -> HSI48 {
// Reset CRS peripheral
self.rb.apb1rstr.modify(|_, w| w.crsrst().set_bit());
self.rb.apb1rstr.modify(|_, w| w.crsrst().clear_bit());
// Enable CRS peripheral
self.rb.apb1enr.modify(|_, w| w.crsen().set_bit());
// Initialize CRS
crs.cfgr.write(|w|
// Select LSE as synchronization source
unsafe { w.syncsrc().bits(0b01) });
crs.cr
.modify(|_, w| w.autotrimen().set_bit().cen().set_bit());
// Enable VREFINT reference for HSI48 oscillator
syscfg
.syscfg
.cfgr3
.modify(|_, w| w.enref_hsi48().set_bit().en_vrefint().set_bit());
// Select HSI48 as USB clock
self.rb.ccipr.modify(|_, w| w.hsi48msel().set_bit());
// Enable dedicated USB clock
self.rb.crrcr.modify(|_, w| w.hsi48on().set_bit());
while self.rb.crrcr.read().hsi48rdy().bit_is_clear() {}
HSI48(())
}
}
impl Rcc {
/// Configure MCO (Microcontroller Clock Output).
pub fn configure_mco<P>(
&mut self,
source: MCOSEL_A,
prescaler: MCOPRE_A,
output_pin: P,
) -> MCOEnabled
where
P: mco::Pin,
{
output_pin.into_mco();
self.rb.cfgr.modify(|_, w| {
w.mcosel().variant(source);
w.mcopre().variant(prescaler)
});
MCOEnabled(())
}
}
*/
/// Extension trait that freezes the `RCC` peripheral with provided clocks configuration
pub trait RccExt {
unsafe fn freeze(self, config: Config) -> Rcc;
}
impl RccExt for pac::rcc::Rcc {
// `cfgr` is almost always a constant, so make sure it can be constant-propagated properly by
// marking this function and all `Config` constructors and setters as `#[inline]`.
// This saves ~900 Bytes for the `pwr.rs` example.
#[inline]
unsafe fn freeze(self, cfgr: Config) -> Rcc {
let (sys_clk, sw) = match cfgr.mux {
ClockSrc::MSI(range) => {
// Set MSI range
self.icscr().write(|w| w.set_msirange(range.into()));
// Enable MSI
self.cr().write(|w| w.set_msion(Pllon::ENABLED));
while !self.cr().read().msirdy() {}
let freq = 32_768 * (1 << (range as u8 + 1));
(freq, Sw::MSI)
}
ClockSrc::HSI16 => {
// Enable HSI16
self.cr().write(|w| w.set_hsi16on(Pllon::ENABLED));
while !self.cr().read().hsi16rdyf() {}
(HSI_FREQ, Sw::HSI16)
}
ClockSrc::HSE(freq) => {
// Enable HSE
self.cr().write(|w| w.set_hseon(Pllon::ENABLED));
while !self.cr().read().hserdy() {}
(freq.0, Sw::HSE)
}
ClockSrc::PLL(src, mul, div) => {
let freq = match src {
PLLSource::HSE(freq) => {
// Enable HSE
self.cr().write(|w| w.set_hseon(Pllon::ENABLED));
while !self.cr().read().hserdy() {}
freq.0
}
PLLSource::HSI16 => {
// Enable HSI
self.cr().write(|w| w.set_hsi16on(Pllon::ENABLED));
while !self.cr().read().hsi16rdyf() {}
HSI_FREQ
}
};
// Disable PLL
self.cr().modify(|w| w.set_pllon(Pllon::DISABLED));
while self.cr().read().pllrdy() {}
let freq = match mul {
PLLMul::Mul3 => freq * 3,
PLLMul::Mul4 => freq * 4,
PLLMul::Mul6 => freq * 6,
PLLMul::Mul8 => freq * 8,
PLLMul::Mul12 => freq * 12,
PLLMul::Mul16 => freq * 16,
PLLMul::Mul24 => freq * 24,
PLLMul::Mul32 => freq * 32,
PLLMul::Mul48 => freq * 48,
};
let freq = match div {
PLLDiv::Div2 => freq / 2,
PLLDiv::Div3 => freq / 3,
PLLDiv::Div4 => freq / 4,
};
assert!(freq <= 32_u32.mhz().0);
self.cfgr().write(move |w| {
w.set_pllmul(mul.into());
w.set_plldiv(div.into());
w.set_pllsrc(src.into());
});
// Enable PLL
self.cr().modify(|w| w.set_pllon(Pllon::ENABLED));
while !self.cr().read().pllrdy() {}
(freq, Sw::PLL)
}
};
self.cfgr().modify(|w| {
w.set_sw(sw.into());
w.set_hpre(cfgr.ahb_pre.into());
w.set_ppre(0, cfgr.apb1_pre.into());
w.set_ppre(1, cfgr.apb2_pre.into());
});
let ahb_freq: u32 = match cfgr.ahb_pre {
AHBPrescaler::NotDivided => sys_clk,
pre => {
let pre: Hpre = pre.into();
let pre = 1 << (pre.0 as u32 - 7);
sys_clk / pre
}
};
let (apb1_freq, apb1_tim_freq, apb1_pre) = match cfgr.apb1_pre {
APBPrescaler::NotDivided => (ahb_freq, ahb_freq, 1),
pre => {
let pre: Ppre = pre.into();
let pre: u8 = 1 << (pre.0 - 3);
let freq = ahb_freq / pre as u32;
(freq, freq * 2, pre as u8)
}
};
let (apb2_freq, apb2_tim_freq, apb2_pre) = match cfgr.apb2_pre {
APBPrescaler::NotDivided => (ahb_freq, ahb_freq, 1),
pre => {
let pre: Ppre = pre.into();
let pre: u8 = 1 << (pre.0 - 3);
let freq = ahb_freq / (1 << (pre as u8 - 3));
(freq, freq * 2, pre as u8)
}
};
let clocks = Clocks {
source: cfgr.mux,
sys_clk: sys_clk.hz(),
ahb_clk: ahb_freq.hz(),
apb1_clk: apb1_freq.hz(),
apb2_clk: apb2_freq.hz(),
apb1_tim_clk: apb1_tim_freq.hz(),
apb2_tim_clk: apb2_tim_freq.hz(),
apb1_pre,
apb2_pre,
};
Rcc { rb: self, clocks }
}
}
/// Frozen clock frequencies
///
/// The existence of this value indicates that the clock configuration can no longer be changed
#[derive(Clone, Copy)]
pub struct Clocks {
source: ClockSrc,
sys_clk: Hertz,
ahb_clk: Hertz,
apb1_clk: Hertz,
apb1_tim_clk: Hertz,
apb2_clk: Hertz,
apb2_tim_clk: Hertz,
apb1_pre: u8,
apb2_pre: u8,
}
impl Clocks {
/// Returns the clock source
pub fn source(&self) -> &ClockSrc {
&self.source
}
/// Returns the system (core) frequency
pub fn sys_clk(&self) -> Hertz {
self.sys_clk
}
/// Returns the frequency of the AHB
pub fn ahb_clk(&self) -> Hertz {
self.ahb_clk
}
/// Returns the frequency of the APB1
pub fn apb1_clk(&self) -> Hertz {
self.apb1_clk
}
/// Returns the frequency of the APB1 timers
pub fn apb1_tim_clk(&self) -> Hertz {
self.apb1_tim_clk
}
/// Returns the prescaler of the APB1
pub fn apb1_pre(&self) -> u8 {
self.apb1_pre
}
/// Returns the frequency of the APB2
pub fn apb2_clk(&self) -> Hertz {
self.apb2_clk
}
/// Returns the frequency of the APB2 timers
pub fn apb2_tim_clk(&self) -> Hertz {
self.apb2_tim_clk
}
/// Returns the prescaler of the APB2
pub fn apb2_pre(&self) -> u8 {
self.apb2_pre
}
}
/// Token that exists only, if the HSI48 clock has been enabled
///
/// You can get an instance of this struct by calling [`Rcc::enable_hsi48`].
#[derive(Clone, Copy)]
pub struct HSI48(());
/// Token that exists only if MCO (Microcontroller Clock Out) has been enabled.
///
/// You can get an instance of this struct by calling [`Rcc::configure_mco`].
#[derive(Clone, Copy)]
pub struct MCOEnabled(());
/// Token that exists only, if the LSE clock has been enabled
///
/// You can get an instance of this struct by calling [`Rcc::enable_lse`].
#[derive(Clone, Copy)]
pub struct LSE(());
impl Into<Pllmul> for PLLMul {
fn into(self) -> Pllmul {
match self {
PLLMul::Mul3 => Pllmul::MUL3,
PLLMul::Mul4 => Pllmul::MUL4,
PLLMul::Mul6 => Pllmul::MUL6,
PLLMul::Mul8 => Pllmul::MUL8,
PLLMul::Mul12 => Pllmul::MUL12,
PLLMul::Mul16 => Pllmul::MUL16,
PLLMul::Mul24 => Pllmul::MUL24,
PLLMul::Mul32 => Pllmul::MUL32,
PLLMul::Mul48 => Pllmul::MUL48,
}
}
}
impl Into<Plldiv> for PLLDiv {
fn into(self) -> Plldiv {
match self {
PLLDiv::Div2 => Plldiv::DIV2,
PLLDiv::Div3 => Plldiv::DIV3,
PLLDiv::Div4 => Plldiv::DIV4,
}
}
}
impl Into<Pllsrc> for PLLSource {
fn into(self) -> Pllsrc {
match self {
PLLSource::HSI16 => Pllsrc::HSI16,
PLLSource::HSE(_) => Pllsrc::HSE,
}
}
}
impl Into<Ppre> for APBPrescaler {
fn into(self) -> Ppre {
match self {
APBPrescaler::NotDivided => Ppre::DIV1,
APBPrescaler::Div2 => Ppre::DIV2,
APBPrescaler::Div4 => Ppre::DIV4,
APBPrescaler::Div8 => Ppre::DIV8,
APBPrescaler::Div16 => Ppre::DIV16,
}
}
}
impl Into<Hpre> for AHBPrescaler {
fn into(self) -> Hpre {
match self {
AHBPrescaler::NotDivided => Hpre::DIV1,
AHBPrescaler::Div2 => Hpre::DIV2,
AHBPrescaler::Div4 => Hpre::DIV4,
AHBPrescaler::Div8 => Hpre::DIV8,
AHBPrescaler::Div16 => Hpre::DIV16,
AHBPrescaler::Div64 => Hpre::DIV64,
AHBPrescaler::Div128 => Hpre::DIV128,
AHBPrescaler::Div256 => Hpre::DIV256,
AHBPrescaler::Div512 => Hpre::DIV512,
}
}
}
impl Into<Msirange> for MSIRange {
fn into(self) -> Msirange {
match self {
MSIRange::Range0 => Msirange::RANGE0,
MSIRange::Range1 => Msirange::RANGE1,
MSIRange::Range2 => Msirange::RANGE2,
MSIRange::Range3 => Msirange::RANGE3,
MSIRange::Range4 => Msirange::RANGE4,
MSIRange::Range5 => Msirange::RANGE5,
MSIRange::Range6 => Msirange::RANGE6,
}
}
}
// We use TIM2 as SystemClock
pub type SystemClock = Clock<TIM2>;
pub unsafe fn init(config: Config) -> SystemClock {
let rcc = pac::RCC;
let enabled = vals::Iophen::ENABLED;
@ -17,4 +580,16 @@ pub unsafe fn init(config: Config) {
w.set_iopeen(enabled);
w.set_iophen(enabled);
});
let r = rcc.freeze(config);
rcc.apb1enr().modify(|w| w.set_tim2en(Lptimen::ENABLED));
rcc.apb1rstr().modify(|w| w.set_tim2rst(true));
rcc.apb1rstr().modify(|w| w.set_tim2rst(false));
Clock::new(
<peripherals::TIM2 as embassy::util::Steal>::steal(),
interrupt::take!(TIM2),
r.clocks.apb1_clk(),
)
}

View file

@ -6,8 +6,10 @@ cfg_if::cfg_if! {
mod l0;
pub use l0::*;
} else {
pub type SystemClock = ();
#[derive(Default)]
pub struct Config {}
pub fn init(_config: Config) {}
pub unsafe fn init(_config: Config) -> SystemClock {
}
}
}