flash: h50: first pass at implementation

2 files changed, 126 insertions, 1 deletions

diff --git a/embassy-stm32/src/flash/h50.rs b/embassy-stm32/src/flash/h50.rs
new file mode 100644
index 000000000..db05bef5d
--- /dev/null
+++ b/embassy-stm32/src/flash/h50.rs
@@ -0,0 +1,124 @@
+/// STM32H50 series flash impl. See RM0492
+use core::{
+    ptr::write_volatile,
+    sync::atomic::{fence, Ordering},
+};
+
+use cortex_m::interrupt;
+use pac::flash::regs::Nssr;
+use pac::flash::vals::Bksel;
+
+use super::{Error, FlashBank, FlashRegion, FlashSector, FLASH_REGIONS, WRITE_SIZE};
+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.nscr().modify(|w| w.set_lock(true));
+}
+
+pub(crate) unsafe fn unlock() {
+    while busy() {}
+
+    if pac::FLASH.nscr().read().lock() {
+        pac::FLASH.nskeyr().write_value(0x4567_0123);
+        pac::FLASH.nskeyr().write_value(0xCDEF_89AB);
+    }
+}
+
+pub(crate) unsafe fn enable_blocking_write() {
+    assert_eq!(0, WRITE_SIZE % 4);
+    pac::FLASH.nscr().write(|w| w.set_pg(true));
+}
+
+pub(crate) unsafe fn disable_blocking_write() {
+    pac::FLASH.nscr().write(|w| w.set_pg(false));
+}
+
+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);
+    }
+
+    wait_ready_blocking()
+}
+
+pub(crate) unsafe fn blocking_erase_sector(sector: &FlashSector) -> Result<(), Error> {
+    assert!(sector.bank != FlashBank::Otp);
+    assert!(sector.index_in_bank < 8);
+
+    while busy() {}
+
+    interrupt::free(|_| {
+        pac::FLASH.nscr().modify(|w| {
+            w.set_bksel(match sector.bank {
+                FlashBank::Bank1 => Bksel::B_0X0,
+                FlashBank::Bank2 => Bksel::B_0X1,
+                _ => unreachable!(),
+            });
+            w.set_snb(sector.index_in_bank);
+            w.set_ser(true);
+            w.set_strt(true);
+        })
+    });
+
+    let ret = wait_ready_blocking();
+    pac::FLASH.nscr().modify(|w| w.set_ser(false));
+    ret
+}
+
+pub(crate) unsafe fn wait_ready_blocking() -> Result<(), Error> {
+    loop {
+        let sr = pac::FLASH.nssr().read();
+
+        if !sr_busy(sr) {
+            if sr.wrperr() {
+                return Err(Error::Protected);
+            }
+            if sr.pgserr() {
+                return Err(Error::Seq);
+            }
+            if sr.strberr() {
+                // writing several times to the same byte in the write buffer
+                return Err(Error::Prog);
+            }
+            if sr.incerr() {
+                // attempting write operation before completion of previous
+                // write operation
+                return Err(Error::Seq);
+            }
+
+            return Ok(());
+        }
+    }
+}
+
+pub(crate) unsafe fn clear_all_err() {
+    pac::FLASH.nsccr().modify(|w| {
+        w.set_clr_wrperr(true);
+        w.set_clr_pgserr(true);
+        w.set_clr_strberr(true);
+        w.set_clr_incerr(true);
+    })
+}
+
+fn sr_busy(sr: Nssr) -> bool {
+    // Note: RM0492 sometimes incorrectly refers to WBNE as NSWBNE
+    sr.bsy() || sr.dbne() || sr.wbne()
+}
+
+fn busy() -> bool {
+    let sr = pac::FLASH.nssr().read();
+    sr_busy(sr)
+}
diff --git a/embassy-stm32/src/flash/mod.rs b/embassy-stm32/src/flash/mod.rs
index 4f43a7a48..1d8031e82 100644
--- a/embassy-stm32/src/flash/mod.rs
+++ b/embassy-stm32/src/flash/mod.rs
@@ -102,10 +102,11 @@ pub enum FlashBank {
 #[cfg_attr(flash_h7, path = "h7.rs")]
 #[cfg_attr(flash_h7ab, path = "h7.rs")]
 #[cfg_attr(flash_u5, path = "u5.rs")]
+#[cfg_attr(flash_h50, path = "h50.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_u5
+        flash_g4, flash_h7, flash_h7ab, flash_u5, flash_h50
     )),
     path = "other.rs"
 )]