support u5 flash

2 files changed, 107 insertions, 1 deletions

diff --git a/embassy-stm32/src/flash/mod.rs b/embassy-stm32/src/flash/mod.rs
index 47232f4a4..4f43a7a48 100644
--- a/embassy-stm32/src/flash/mod.rs
+++ b/embassy-stm32/src/flash/mod.rs
@@ -101,10 +101,11 @@ pub enum FlashBank {
 #[cfg_attr(any(flash_g0, flash_g4), path = "g.rs")]
 #[cfg_attr(flash_h7, path = "h7.rs")]
 #[cfg_attr(flash_h7ab, path = "h7.rs")]
+#[cfg_attr(flash_u5, path = "u5.rs")]
 #[cfg_attr(
     not(any(
         flash_l0, flash_l1, flash_l4, flash_wl, flash_wb, flash_f0, flash_f1, flash_f3, flash_f4, flash_f7, flash_g0,
-        flash_g4, flash_h7, flash_h7ab
+        flash_g4, flash_h7, flash_h7ab, flash_u5
     )),
     path = "other.rs"
 )]
diff --git a/embassy-stm32/src/flash/u5.rs b/embassy-stm32/src/flash/u5.rs
new file mode 100644
index 000000000..3787082f9
--- /dev/null
+++ b/embassy-stm32/src/flash/u5.rs
@@ -0,0 +1,105 @@
+use core::convert::TryInto;
+use core::ptr::write_volatile;
+use core::sync::atomic::{fence, Ordering};
+
+use super::{FlashRegion, FlashSector, FLASH_REGIONS, WRITE_SIZE};
+use crate::flash::Error;
+use crate::pac;
+
+pub(crate) const fn is_default_layout() -> bool {
+    true
+}
+
+pub(crate) const fn get_flash_regions() -> &'static [&'static FlashRegion] {
+    &FLASH_REGIONS
+}
+
+pub(crate) unsafe fn lock() {
+    pac::FLASH.seccr().modify(|w| w.set_lock(true));
+}
+
+pub(crate) unsafe fn unlock() {
+    if pac::FLASH.seccr().read().lock() {
+        pac::FLASH.seckeyr().write_value(0x4567_0123);
+        pac::FLASH.seckeyr().write_value(0xCDEF_89AB);
+    }
+}
+
+pub(crate) unsafe fn enable_blocking_write() {
+    assert_eq!(0, WRITE_SIZE % 4);
+
+    pac::FLASH.seccr().write(|w| {
+        w.set_pg(pac::flash::vals::SeccrPg::B_0X1);
+    });
+}
+
+pub(crate) unsafe fn disable_blocking_write() {
+    pac::FLASH.seccr().write(|w| w.set_pg(pac::flash::vals::SeccrPg::B_0X0));
+}
+
+pub(crate) unsafe fn blocking_write(start_address: u32, buf: &[u8; WRITE_SIZE]) -> Result<(), Error> {
+    let mut address = start_address;
+    for val in buf.chunks(4) {
+        write_volatile(address as *mut u32, u32::from_le_bytes(val.try_into().unwrap()));
+        address += val.len() as u32;
+
+        // prevents parallelism errors
+        fence(Ordering::SeqCst);
+    }
+
+    blocking_wait_ready()
+}
+
+pub(crate) unsafe fn blocking_erase_sector(sector: &FlashSector) -> Result<(), Error> {
+    pac::FLASH.seccr().modify(|w| {
+        w.set_per(pac::flash::vals::SeccrPer::B_0X1);
+        w.set_pnb(sector.index_in_bank)
+    });
+
+    pac::FLASH.seccr().modify(|w| {
+        w.set_strt(true);
+    });
+
+    let ret: Result<(), Error> = blocking_wait_ready();
+    pac::FLASH
+        .seccr()
+        .modify(|w| w.set_per(pac::flash::vals::SeccrPer::B_0X0));
+    clear_all_err();
+    ret
+}
+
+pub(crate) unsafe fn clear_all_err() {
+    // read and write back the same value.
+    // This clears all "write 1 to clear" bits.
+    pac::FLASH.secsr().modify(|_| {});
+}
+
+unsafe fn blocking_wait_ready() -> Result<(), Error> {
+    loop {
+        let sr = pac::FLASH.secsr().read();
+
+        if !sr.bsy() {
+            if sr.pgserr() {
+                return Err(Error::Seq);
+            }
+
+            if sr.sizerr() {
+                return Err(Error::Size);
+            }
+
+            if sr.pgaerr() {
+                return Err(Error::Unaligned);
+            }
+
+            if sr.wrperr() {
+                return Err(Error::Protected);
+            }
+
+            if sr.progerr() {
+                return Err(Error::Prog);
+            }
+
+            return Ok(());
+        }
+    }
+}