From e08e6cc3b278a148fc90bf5d13506dfed5b06244 Mon Sep 17 00:00:00 2001
From: Frederik Menke <frederik.menke@rwth-aachen.de>
Date: Sat, 6 Jul 2024 13:03:44 +0200
Subject: [PATCH] Only read out partition volume names

---
 src/main.rs | 30 +++++++++++++++++++++++-------
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 7c0704a..27b1c7f 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -13,6 +13,7 @@ use embassy_executor::Spawner;
 use embassy_rp::spi::Spi;
 use embassy_rp::{gpio, spi};
 use embedded_hal_bus::spi::ExclusiveDevice;
+use embedded_sdmmc::fat::Bpb;
 use embedded_sdmmc::sdcard::{DummyCsPin, SdCard};
 use embedded_sdmmc::{Block, BlockCount, BlockDevice, BlockIdx, FatVolume, VolumeIdx, VolumeType};
 use gpio::{Level, Output};
@@ -60,8 +61,8 @@ async fn main(_spawner: Spawner) {
     let mut volume_mgr = embedded_sdmmc::VolumeManager::new(sdcard, DummyTimesource());
     {
         let device = volume_mgr.device();
-        let info = read_volume_info(device, VolumeIdx(0)).unwrap();
-        info!("Volume 0: name: {:?}", defmt::Debug2Format(&info));
+        let info = read_volume_label(device, VolumeIdx(0)).unwrap();
+        info!("Volume 0: name: {:?}", core::str::from_utf8(&info).unwrap());
     }
 
     // Try and access Volume 0 (i.e. the first partition).
@@ -90,6 +91,7 @@ async fn main(_spawner: Spawner) {
         }
     }
     {
+        // Append some text to the end of the file
         let mut my_file = root_dir
             .open_file_in_dir("MY_FILE.TXT", embedded_sdmmc::Mode::ReadWriteAppend)
             .unwrap();
@@ -100,10 +102,14 @@ async fn main(_spawner: Spawner) {
     info!("Program end")
 }
 
-pub fn read_volume_info<D>(
+/// Read out the volume label a partition
+///
+/// I mostly pulled out some interiors of `embedded_sdmmc` and plugged
+/// them back together.
+pub fn read_volume_label<D>(
     block_device: &mut D,
     volume_idx: VolumeIdx,
-) -> Result<FatVolume, embedded_sdmmc::Error<D::Error>>
+) -> Result<[u8; 11], embedded_sdmmc::Error<D::Error>>
 where
     D: BlockDevice,
 {
@@ -173,9 +179,19 @@ where
         | PARTITION_ID_FAT32_LBA
         | PARTITION_ID_FAT16_LBA
         | PARTITION_ID_FAT16 => {
-            let volume = embedded_sdmmc::fat::parse_volume(block_device, lba_start, num_blocks)?;
-            let VolumeType::Fat(fat) = volume;
-            Ok(fat)
+            let label = {
+                let mut blocks = [Block::new()];
+                block_device
+                    .read(&mut blocks, lba_start, "read_bpb")
+                    .map_err(Error::DeviceError)?;
+                let block = &blocks[0];
+                let bpb = embedded_sdmmc::fat::Bpb::create_from_bytes(block)
+                    .map_err(Error::FormatError)?;
+                let mut label = [0u8; 11];
+                label.copy_from_slice(&bpb.volume_label()[0..11]);
+                label
+            };
+            Ok(label)
         }
         _ => Err(Error::FormatError("Partition type not supported")),
     }