From 039acda3a8b9549a6056aafdc4344ea4c76b9f60 Mon Sep 17 00:00:00 2001
From: chemicstry <chemicstry@gmail.com>
Date: Thu, 14 Jul 2022 19:41:39 +0300
Subject: [PATCH] Fix writing to last sector of F4 flash

---
 embassy-stm32/src/flash/f4.rs     |  6 ++++--
 examples/stm32f4/src/bin/flash.rs | 32 ++++++++++++++++++++-----------
 2 files changed, 25 insertions(+), 13 deletions(-)

diff --git a/embassy-stm32/src/flash/f4.rs b/embassy-stm32/src/flash/f4.rs
index f6dc7e95..ad71f145 100644
--- a/embassy-stm32/src/flash/f4.rs
+++ b/embassy-stm32/src/flash/f4.rs
@@ -99,9 +99,9 @@ unsafe fn get_sector(addr: u32) -> u8 {
 
 pub(crate) unsafe fn blocking_erase(from: u32, to: u32) -> Result<(), Error> {
     let start_sector = get_sector(from);
-    let end_sector = get_sector(to);
+    let end_sector = get_sector(to - 1); // end range is exclusive
 
-    for sector in start_sector..end_sector {
+    for sector in start_sector..=end_sector {
         let ret = erase_sector(sector as u8);
         if ret.is_err() {
             return ret;
@@ -115,6 +115,8 @@ unsafe fn erase_sector(sector: u8) -> Result<(), Error> {
     let bank = sector / SECOND_BANK_SECTOR_START as u8;
     let snb = (bank << 4) + (sector % SECOND_BANK_SECTOR_START as u8);
 
+    trace!("Erasing sector: {}", sector);
+
     pac::FLASH.cr().modify(|w| {
         w.set_ser(true);
         w.set_snb(snb)
diff --git a/examples/stm32f4/src/bin/flash.rs b/examples/stm32f4/src/bin/flash.rs
index b531d6f1..ad45df82 100644
--- a/examples/stm32f4/src/bin/flash.rs
+++ b/examples/stm32f4/src/bin/flash.rs
@@ -7,36 +7,46 @@ use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
 use embassy_stm32::flash::Flash;
 use embassy_stm32::Peripherals;
-use embedded_storage::nor_flash::{NorFlash, ReadNorFlash};
 use {defmt_rtt as _, panic_probe as _};
 
 #[embassy::main]
 async fn main(_spawner: Spawner, p: Peripherals) {
     info!("Hello Flash!");
 
-    const ADDR: u32 = 0x10_0000;
-
-    // wait a bit before accessing the flash
-    Timer::after(Duration::from_millis(300)).await;
-
     let mut f = Flash::unlock(p.FLASH);
 
+    // Sector 5
+    test_flash(&mut f, 128 * 1024, 128 * 1024);
+
+    // Sector 11, last in bank 1
+    test_flash(&mut f, (1024 - 128) * 1024, 128 * 1024);
+
+    // Sectors 12..=16, start of bank 2 (16K, 16K, 16K, 16K, 64K)
+    test_flash(&mut f, 1024 * 1024, 128 * 1024);
+
+    // Sectors 23, last in bank 2
+    test_flash(&mut f, (2048 - 128) * 1024, 128 * 1024);
+}
+
+fn test_flash(f: &mut Flash, offset: u32, size: u32) {
+    info!("Testing offset: {=u32:#X}, size: {=u32:#X}", offset, size);
+
     info!("Reading...");
     let mut buf = [0u8; 32];
-    unwrap!(f.read(ADDR, &mut buf));
+    unwrap!(f.read(offset, &mut buf));
     info!("Read: {=[u8]:x}", buf);
 
     info!("Erasing...");
-    unwrap!(f.erase(ADDR, ADDR + 128 * 1024));
+    unwrap!(f.erase(offset, offset + size));
 
     info!("Reading...");
     let mut buf = [0u8; 32];
-    unwrap!(f.read(ADDR, &mut buf));
+    unwrap!(f.read(offset, &mut buf));
     info!("Read after erase: {=[u8]:x}", buf);
 
     info!("Writing...");
     unwrap!(f.write(
-        ADDR,
+        offset,
         &[
             1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
             30, 31, 32
@@ -45,7 +55,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
 
     info!("Reading...");
     let mut buf = [0u8; 32];
-    unwrap!(f.read(ADDR, &mut buf));
+    unwrap!(f.read(offset, &mut buf));
     info!("Read: {=[u8]:x}", buf);
     assert_eq!(
         &buf[..],