From 42b21fd7ae93fe0a1542ab265d01b1a808390f26 Mon Sep 17 00:00:00 2001
From: dev-guruprasath <96348958+dev-guruprasath@users.noreply.github.com>
Date: Mon, 31 Jul 2023 13:56:16 +0530
Subject: [PATCH] added flash support

---
 embassy-stm32/src/flash/g0.rs  | 115 +++++++++++++++++++++++++++++++++
 embassy-stm32/src/flash/mod.rs |   3 +-
 2 files changed, 117 insertions(+), 1 deletion(-)
 create mode 100644 embassy-stm32/src/flash/g0.rs

diff --git a/embassy-stm32/src/flash/g0.rs b/embassy-stm32/src/flash/g0.rs
new file mode 100644
index 000000000..60ff1abf1
--- /dev/null
+++ b/embassy-stm32/src/flash/g0.rs
@@ -0,0 +1,115 @@
+use core::convert::TryInto;
+use core::ptr::write_volatile;
+use core::sync::atomic::{fence, Ordering};
+
+use cortex_m::interrupt;
+
+use super::{FlashRegion, FlashSector, FLASH_REGIONS, WRITE_SIZE};
+use crate::flash::Error;
+use crate::pac;
+
+pub const fn is_default_layout() -> bool {
+    true
+}
+
+pub const fn get_flash_regions() -> &'static [&'static FlashRegion] {
+    &FLASH_REGIONS
+}
+
+pub(crate) unsafe fn lock() {
+    pac::FLASH.cr().modify(|w| w.set_lock(true));
+}
+pub(crate) unsafe fn unlock() {
+    // Wait, while the memory interface is busy.
+    while pac::FLASH.sr().read().bsy() {}
+
+    // Unlock flash
+    pac::FLASH.keyr().write(|w| w.set_keyr(0x4567_0123));
+    pac::FLASH.keyr().write(|w| w.set_keyr(0xCDEF_89AB));
+}
+
+pub(crate) unsafe fn enable_blocking_write() {
+    assert_eq!(0, WRITE_SIZE % 4);
+    pac::FLASH.cr().write(|w| w.set_pg(true));
+}
+
+pub(crate) unsafe fn disable_blocking_write() {
+    pac::FLASH.cr().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> {
+    let idx = (sector.start - super::FLASH_BASE as u32) / super::BANK1_REGION.erase_size as u32;
+    while pac::FLASH.sr().read().bsy() {}
+    clear_all_err();
+
+    interrupt::free(|_| {
+        pac::FLASH.cr().modify(|w| {
+            w.set_per(true);
+            w.set_pnb(idx as u8);
+            w.set_strt(true);
+        });
+    });
+
+    let ret: Result<(), Error> = wait_ready_blocking();
+    pac::FLASH.cr().modify(|w| w.set_per(false));
+    ret
+}
+
+pub(crate) unsafe fn wait_ready_blocking() -> Result<(), Error> {
+    while pac::FLASH.sr().read().bsy() {}
+
+    let sr = pac::FLASH.sr().read();
+
+    if sr.progerr() {
+        return Err(Error::Prog);
+    }
+
+    if sr.wrperr() {
+        return Err(Error::Protected);
+    }
+
+    if sr.pgaerr() {
+        return Err(Error::Unaligned);
+    }
+
+    Ok(())
+}
+
+pub(crate) unsafe fn clear_all_err() {
+    pac::FLASH.sr().modify(|w| {
+        if w.progerr() {
+            w.set_progerr(true);
+        }
+        if w.pgserr() {
+            w.set_pgserr(true);
+        }
+        if w.rderr() {
+            w.set_rderr(true);
+        }
+        if w.optverr() {
+            w.set_optverr(true);
+        }
+        if w.sizerr() {
+            w.set_sizerr(true);
+        }
+        if w.pgaerr() {
+            w.set_pgaerr(true);
+        }
+        if w.wrperr() {
+            w.set_wrperr(true);
+        }
+    });
+}
diff --git a/embassy-stm32/src/flash/mod.rs b/embassy-stm32/src/flash/mod.rs
index f44ef2c16..4308037f2 100644
--- a/embassy-stm32/src/flash/mod.rs
+++ b/embassy-stm32/src/flash/mod.rs
@@ -63,10 +63,11 @@ impl FlashRegion {
 #[cfg_attr(flash_f3, path = "f3.rs")]
 #[cfg_attr(flash_f4, path = "f4.rs")]
 #[cfg_attr(flash_f7, path = "f7.rs")]
+#[cfg_attr(flash_g0, path = "g0.rs")]
 #[cfg_attr(flash_h7, path = "h7.rs")]
 #[cfg_attr(
     not(any(
-        flash_l0, flash_l1, flash_l4, flash_wl, flash_wb, flash_f0, flash_f3, flash_f4, flash_f7, flash_h7
+        flash_l0, flash_l1, flash_l4, flash_wl, flash_wb, flash_f0, flash_f3, flash_f4, flash_f7, flash_g0, flash_h7
     )),
     path = "other.rs"
 )]