1use embedded_storage::nor_flash::{ErrorType, NorFlash, NorFlashError, ReadNorFlash};
2use embedded_storage_async::nor_flash::{NorFlash as AsyncNorFlash, ReadNorFlash as AsyncReadNorFlash};
3
4/// Convenience helper for concatenating two consecutive flashes into one.
5/// This is especially useful if used with "flash regions", where one may
6/// want to concatenate multiple regions into one larger region.
7pub struct ConcatFlash<First, Second>(First, Second);
8
9impl<First, Second> ConcatFlash<First, Second> {
10 /// Create a new flash that concatenates two consecutive flashes.
11 pub fn new(first: First, second: Second) -> Self {
12 Self(first, second)
13 }
14}
15
16const fn get_read_size(first_read_size: usize, second_read_size: usize) -> usize {
17 if first_read_size != second_read_size {
18 panic!("The read size for the concatenated flashes must be the same");
19 }
20 first_read_size
21}
22
23const fn get_write_size(first_write_size: usize, second_write_size: usize) -> usize {
24 if first_write_size != second_write_size {
25 panic!("The write size for the concatenated flashes must be the same");
26 }
27 first_write_size
28}
29
30const fn get_max_erase_size(first_erase_size: usize, second_erase_size: usize) -> usize {
31 let max_erase_size: usize = if first_erase_size > second_erase_size {
32 first_erase_size
33 } else {
34 second_erase_size
35 };
36 if max_erase_size % first_erase_size != 0 || max_erase_size % second_erase_size != 0 {
37 panic!("The erase sizes for the concatenated flashes must have have a gcd equal to the max erase size");
38 }
39 max_erase_size
40}
41
42impl<First, Second, E> ErrorType for ConcatFlash<First, Second>
43where
44 First: ErrorType<Error = E>,
45 Second: ErrorType<Error = E>,
46 E: NorFlashError,
47{
48 type Error = E;
49}
50
51impl<First, Second, E> ReadNorFlash for ConcatFlash<First, Second>
52where
53 First: ReadNorFlash<Error = E>,
54 Second: ReadNorFlash<Error = E>,
55 E: NorFlashError,
56{
57 const READ_SIZE: usize = get_read_size(First::READ_SIZE, Second::READ_SIZE);
58
59 fn read(&mut self, mut offset: u32, mut bytes: &mut [u8]) -> Result<(), E> {
60 if offset < self.0.capacity() as u32 {
61 let len: usize = core::cmp::min(self.0.capacity() - offset as usize, v2:bytes.len());
62 self.0.read(offset, &mut bytes[..len])?;
63 offset += len as u32;
64 bytes = &mut bytes[len..];
65 }
66
67 if !bytes.is_empty() {
68 self.1.read(offset:offset - self.0.capacity() as u32, bytes)?;
69 }
70
71 Ok(())
72 }
73
74 fn capacity(&self) -> usize {
75 self.0.capacity() + self.1.capacity()
76 }
77}
78
79impl<First, Second, E> NorFlash for ConcatFlash<First, Second>
80where
81 First: NorFlash<Error = E>,
82 Second: NorFlash<Error = E>,
83 E: NorFlashError,
84{
85 const WRITE_SIZE: usize = get_write_size(First::WRITE_SIZE, Second::WRITE_SIZE);
86 const ERASE_SIZE: usize = get_max_erase_size(First::ERASE_SIZE, Second::ERASE_SIZE);
87
88 fn write(&mut self, mut offset: u32, mut bytes: &[u8]) -> Result<(), E> {
89 if offset < self.0.capacity() as u32 {
90 let len = core::cmp::min(self.0.capacity() - offset as usize, bytes.len());
91 self.0.write(offset, &bytes[..len])?;
92 offset += len as u32;
93 bytes = &bytes[len..];
94 }
95
96 if !bytes.is_empty() {
97 self.1.write(offset - self.0.capacity() as u32, bytes)?;
98 }
99
100 Ok(())
101 }
102
103 fn erase(&mut self, mut from: u32, to: u32) -> Result<(), E> {
104 if from < self.0.capacity() as u32 {
105 let to = core::cmp::min(self.0.capacity() as u32, to);
106 self.0.erase(from, to)?;
107 from = self.0.capacity() as u32;
108 }
109
110 if from < to {
111 self.1
112 .erase(from - self.0.capacity() as u32, to - self.0.capacity() as u32)?;
113 }
114
115 Ok(())
116 }
117}
118
119impl<First, Second, E> AsyncReadNorFlash for ConcatFlash<First, Second>
120where
121 First: AsyncReadNorFlash<Error = E>,
122 Second: AsyncReadNorFlash<Error = E>,
123 E: NorFlashError,
124{
125 const READ_SIZE: usize = get_read_size(First::READ_SIZE, Second::READ_SIZE);
126
127 async fn read(&mut self, mut offset: u32, mut bytes: &mut [u8]) -> Result<(), E> {
128 if offset < self.0.capacity() as u32 {
129 let len: usize = core::cmp::min(self.0.capacity() - offset as usize, v2:bytes.len());
130 self.0.read(offset, &mut bytes[..len]).await?;
131 offset += len as u32;
132 bytes = &mut bytes[len..];
133 }
134
135 if !bytes.is_empty() {
136 self.1.read(offset:offset - self.0.capacity() as u32, bytes).await?;
137 }
138
139 Ok(())
140 }
141
142 fn capacity(&self) -> usize {
143 self.0.capacity() + self.1.capacity()
144 }
145}
146
147impl<First, Second, E> AsyncNorFlash for ConcatFlash<First, Second>
148where
149 First: AsyncNorFlash<Error = E>,
150 Second: AsyncNorFlash<Error = E>,
151 E: NorFlashError,
152{
153 const WRITE_SIZE: usize = get_write_size(First::WRITE_SIZE, Second::WRITE_SIZE);
154 const ERASE_SIZE: usize = get_max_erase_size(First::ERASE_SIZE, Second::ERASE_SIZE);
155
156 async fn write(&mut self, mut offset: u32, mut bytes: &[u8]) -> Result<(), E> {
157 if offset < self.0.capacity() as u32 {
158 let len = core::cmp::min(self.0.capacity() - offset as usize, bytes.len());
159 self.0.write(offset, &bytes[..len]).await?;
160 offset += len as u32;
161 bytes = &bytes[len..];
162 }
163
164 if !bytes.is_empty() {
165 self.1.write(offset - self.0.capacity() as u32, bytes).await?;
166 }
167
168 Ok(())
169 }
170
171 async fn erase(&mut self, mut from: u32, to: u32) -> Result<(), E> {
172 if from < self.0.capacity() as u32 {
173 let to = core::cmp::min(self.0.capacity() as u32, to);
174 self.0.erase(from, to).await?;
175 from = self.0.capacity() as u32;
176 }
177
178 if from < to {
179 self.1
180 .erase(from - self.0.capacity() as u32, to - self.0.capacity() as u32)
181 .await?;
182 }
183
184 Ok(())
185 }
186}
187
188#[cfg(test)]
189mod tests {
190 use embedded_storage::nor_flash::{NorFlash, ReadNorFlash};
191
192 use super::ConcatFlash;
193 use crate::flash::mem_flash::MemFlash;
194
195 #[test]
196 fn can_write_and_read_across_flashes() {
197 let first = MemFlash::<64, 16, 4>::default();
198 let second = MemFlash::<64, 64, 4>::default();
199 let mut f = ConcatFlash::new(first, second);
200
201 f.write(60, &[0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88]).unwrap();
202
203 assert_eq!(&[0x11, 0x22, 0x33, 0x44], &f.0.mem[60..]);
204 assert_eq!(&[0x55, 0x66, 0x77, 0x88], &f.1.mem[0..4]);
205
206 let mut read_buf = [0; 8];
207 f.read(60, &mut read_buf).unwrap();
208
209 assert_eq!(&[0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88], &read_buf);
210 }
211
212 #[test]
213 fn can_erase_across_flashes() {
214 let first = MemFlash::<128, 16, 4>::new(0x00);
215 let second = MemFlash::<128, 64, 4>::new(0x00);
216 let mut f = ConcatFlash::new(first, second);
217
218 f.erase(64, 192).unwrap();
219
220 assert_eq!(&[0x00; 64], &f.0.mem[0..64]);
221 assert_eq!(&[0xff; 64], &f.0.mem[64..128]);
222 assert_eq!(&[0xff; 64], &f.1.mem[0..64]);
223 assert_eq!(&[0x00; 64], &f.1.mem[64..128]);
224 }
225}
226