From 095f5ef279b58da0e3b63559b4f1a039538673c9 Mon Sep 17 00:00:00 2001
From: Mathias <mk@blackbird.online>
Date: Tue, 18 Apr 2023 15:49:33 +0200
Subject: [PATCH] Add MAX_ERASE_SIZE const in build script, and use it in
 flash-wide implementation of embedded-storage traits

---
 embassy-stm32/build.rs            | 8 ++++++++
 embassy-stm32/src/flash/common.rs | 6 +++---
 embassy-stm32/src/flash/mod.rs    | 1 +
 3 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/embassy-stm32/build.rs b/embassy-stm32/build.rs
index c7d12e13..7959cca0 100644
--- a/embassy-stm32/build.rs
+++ b/embassy-stm32/build.rs
@@ -255,6 +255,14 @@ fn main() {
         ];
     });
 
+    let max_erase_size = flash_memory_regions
+        .iter()
+        .map(|region| region.settings.as_ref().unwrap().erase_size)
+        .max()
+        .unwrap();
+
+    g.extend(quote! { pub const MAX_ERASE_SIZE: u32 = #max_erase_size });
+
     g.extend(quote! { pub mod flash_regions { #flash_regions } });
 
     // ========
diff --git a/embassy-stm32/src/flash/common.rs b/embassy-stm32/src/flash/common.rs
index 95fe2612..6d7f5597 100644
--- a/embassy-stm32/src/flash/common.rs
+++ b/embassy-stm32/src/flash/common.rs
@@ -2,7 +2,7 @@ use atomic_polyfill::{fence, Ordering};
 use embassy_hal_common::drop::OnDrop;
 use embassy_hal_common::{into_ref, PeripheralRef};
 
-use super::{family, Error, FlashLayout, FlashRegion, FlashSector, FLASH_BASE, FLASH_SIZE, WRITE_SIZE};
+use super::{family, Error, FlashLayout, FlashRegion, FlashSector, FLASH_BASE, FLASH_SIZE, MAX_ERASE_SIZE, WRITE_SIZE};
 use crate::flash::FlashBank;
 use crate::Peripheral;
 
@@ -179,8 +179,8 @@ impl embedded_storage::nor_flash::ReadNorFlash for Flash<'_> {
 }
 
 impl embedded_storage::nor_flash::NorFlash for Flash<'_> {
-    const WRITE_SIZE: usize = 8;
-    const ERASE_SIZE: usize = 2048;
+    const WRITE_SIZE: usize = WRITE_SIZE;
+    const ERASE_SIZE: usize = MAX_ERASE_SIZE;
 
     fn write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Self::Error> {
         self.blocking_write(offset, bytes)
diff --git a/embassy-stm32/src/flash/mod.rs b/embassy-stm32/src/flash/mod.rs
index 231ff1f9..7d5596b1 100644
--- a/embassy-stm32/src/flash/mod.rs
+++ b/embassy-stm32/src/flash/mod.rs
@@ -7,6 +7,7 @@ mod common;
 pub use common::*;
 
 pub use crate::_generated::flash_regions::*;
+pub use crate::_generated::MAX_ERASE_SIZE;
 pub use crate::pac::{FLASH_BASE, FLASH_SIZE, WRITE_SIZE};
 
 #[derive(Debug)]