embassy_embedded_hal/flash/partition/
asynch.rs

1use embassy_sync::blocking_mutex::raw::RawMutex;
2use embassy_sync::mutex::Mutex;
3use embedded_storage::nor_flash::ErrorType;
4use embedded_storage_async::nor_flash::{NorFlash, ReadNorFlash};
5
6use super::Error;
7
8/// A logical partition of an underlying shared flash
9///
10/// A partition holds an offset and a size of the flash,
11/// and is restricted to operate with that range.
12/// There is no guarantee that muliple partitions on the same flash
13/// operate on mutually exclusive ranges - such a separation is up to
14/// the user to guarantee.
15pub struct Partition<'a, M: RawMutex, T: NorFlash> {
16    flash: &'a Mutex<M, T>,
17    offset: u32,
18    size: u32,
19}
20
21impl<'a, M: RawMutex, T: NorFlash> Clone for Partition<'a, M, T> {
22    fn clone(&self) -> Self {
23        Self {
24            flash: self.flash,
25            offset: self.offset,
26            size: self.size,
27        }
28    }
29}
30
31impl<'a, M: RawMutex, T: NorFlash> Partition<'a, M, T> {
32    /// Create a new partition
33    pub const fn new(flash: &'a Mutex<M, T>, offset: u32, size: u32) -> Self {
34        if offset % T::READ_SIZE as u32 != 0 || offset % T::WRITE_SIZE as u32 != 0 || offset % T::ERASE_SIZE as u32 != 0
35        {
36            panic!("Partition offset must be a multiple of read, write and erase size");
37        }
38        if size % T::READ_SIZE as u32 != 0 || size % T::WRITE_SIZE as u32 != 0 || size % T::ERASE_SIZE as u32 != 0 {
39            panic!("Partition size must be a multiple of read, write and erase size");
40        }
41        Self { flash, offset, size }
42    }
43
44    /// Get the partition offset within the flash
45    pub const fn offset(&self) -> u32 {
46        self.offset
47    }
48
49    /// Get the partition size
50    pub const fn size(&self) -> u32 {
51        self.size
52    }
53}
54
55impl<M: RawMutex, T: NorFlash> ErrorType for Partition<'_, M, T> {
56    type Error = Error<T::Error>;
57}
58
59impl<M: RawMutex, T: NorFlash> ReadNorFlash for Partition<'_, M, T> {
60    const READ_SIZE: usize = T::READ_SIZE;
61
62    async fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Self::Error> {
63        if offset + bytes.len() as u32 > self.size {
64            return Err(Error::OutOfBounds);
65        }
66
67        let mut flash = self.flash.lock().await;
68        flash.read(self.offset + offset, bytes).await.map_err(Error::Flash)
69    }
70
71    fn capacity(&self) -> usize {
72        self.size as usize
73    }
74}
75
76impl<M: RawMutex, T: NorFlash> NorFlash for Partition<'_, M, T> {
77    const WRITE_SIZE: usize = T::WRITE_SIZE;
78    const ERASE_SIZE: usize = T::ERASE_SIZE;
79
80    async fn write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Self::Error> {
81        if offset + bytes.len() as u32 > self.size {
82            return Err(Error::OutOfBounds);
83        }
84
85        let mut flash = self.flash.lock().await;
86        flash.write(self.offset + offset, bytes).await.map_err(Error::Flash)
87    }
88
89    async fn erase(&mut self, from: u32, to: u32) -> Result<(), Self::Error> {
90        if to > self.size {
91            return Err(Error::OutOfBounds);
92        }
93
94        let mut flash = self.flash.lock().await;
95        flash
96            .erase(self.offset + from, self.offset + to)
97            .await
98            .map_err(Error::Flash)
99    }
100}
101
102#[cfg(test)]
103mod tests {
104    use embassy_sync::blocking_mutex::raw::NoopRawMutex;
105
106    use super::*;
107    use crate::flash::mem_flash::MemFlash;
108
109    #[futures_test::test]
110    async fn can_read() {
111        let mut flash = MemFlash::<1024, 128, 4>::default();
112        flash.mem[132..132 + 8].fill(0xAA);
113
114        let flash = Mutex::<NoopRawMutex, _>::new(flash);
115        let mut partition = Partition::new(&flash, 128, 256);
116
117        let mut read_buf = [0; 8];
118        partition.read(4, &mut read_buf).await.unwrap();
119
120        assert!(read_buf.iter().position(|&x| x != 0xAA).is_none());
121    }
122
123    #[futures_test::test]
124    async fn can_write() {
125        let flash = MemFlash::<1024, 128, 4>::default();
126
127        let flash = Mutex::<NoopRawMutex, _>::new(flash);
128        let mut partition = Partition::new(&flash, 128, 256);
129
130        let write_buf = [0xAA; 8];
131        partition.write(4, &write_buf).await.unwrap();
132
133        let flash = flash.try_lock().unwrap();
134        assert!(flash.mem[132..132 + 8].iter().position(|&x| x != 0xAA).is_none());
135    }
136
137    #[futures_test::test]
138    async fn can_erase() {
139        let flash = MemFlash::<1024, 128, 4>::new(0x00);
140
141        let flash = Mutex::<NoopRawMutex, _>::new(flash);
142        let mut partition = Partition::new(&flash, 128, 256);
143
144        partition.erase(0, 128).await.unwrap();
145
146        let flash = flash.try_lock().unwrap();
147        assert!(flash.mem[128..256].iter().position(|&x| x != 0xFF).is_none());
148    }
149}
embassy_embedded_hal/flash/partition/asynch.rs

embassy_embedded_hal/flash/partition/
asynch.rs
