diff --git a/esp-storage/src/buffer.rs b/esp-storage/src/buffer.rs new file mode 100644 index 00000000000..c30e75a3b77 --- /dev/null +++ b/esp-storage/src/buffer.rs @@ -0,0 +1,61 @@ +use core::{mem::MaybeUninit, slice}; + +#[cfg(feature = "nor-flash")] +pub fn uninit_slice(bytes: &[u8]) -> &[MaybeUninit] { + unsafe { core::mem::transmute(bytes) } +} + +#[cfg(feature = "bytewise-read")] +pub fn uninit_slice_mut(bytes: &mut [u8]) -> &mut [MaybeUninit] { + unsafe { core::mem::transmute(bytes) } +} + +pub type FlashWordBuffer = FlashBuffer<4, 1>; +pub type FlashSectorBuffer = FlashBuffer<4096, 1024>; + +#[repr(C)] +pub union FlashBuffer { + bytes: [MaybeUninit; M], + words: [MaybeUninit; N], +} + +impl FlashBuffer { + pub const fn uninit() -> Self { + debug_assert!(N * 4 == M); + Self { + words: [MaybeUninit::uninit(); N], + } + } + + pub fn as_bytes(&self) -> &[MaybeUninit] { + unsafe { self.bytes.as_ref() } + } + + pub fn as_bytes_mut(&mut self) -> &mut [MaybeUninit] { + unsafe { self.bytes.as_mut() } + } + + pub fn as_words(&self) -> &[MaybeUninit] { + unsafe { self.words.as_ref() } + } + + pub fn as_words_mut(&mut self) -> &mut [MaybeUninit] { + unsafe { self.words.as_mut() } + } + + pub unsafe fn assume_init_bytes(&self) -> &[u8] { + slice::from_raw_parts(self.bytes.as_ptr() as *const u8, self.bytes.len()) + } + + pub unsafe fn assume_init_bytes_mut(&mut self) -> &mut [u8] { + slice::from_raw_parts_mut(self.bytes.as_mut_ptr() as *mut u8, self.bytes.len()) + } + + pub unsafe fn assume_init_words(&self) -> &[u32] { + slice::from_raw_parts(self.words.as_ptr() as *const u32, self.words.len()) + } + + pub unsafe fn assume_init_words_mut(&mut self) -> &mut [u32] { + slice::from_raw_parts_mut(self.words.as_mut_ptr() as *mut u32, self.words.len()) + } +} diff --git a/esp-storage/src/common.rs b/esp-storage/src/common.rs index d6b0f08a9c3..7efea78e28e 100644 --- a/esp-storage/src/common.rs +++ b/esp-storage/src/common.rs @@ -1,27 +1,6 @@ -use core::ops::{Deref, DerefMut}; +use core::mem::MaybeUninit; -use crate::chip_specific; - -#[repr(C, align(4))] -pub struct FlashSectorBuffer { - // NOTE: Ensure that no unaligned fields are added above `data` to maintain its required - // alignment - data: [u8; FlashStorage::SECTOR_SIZE as usize], -} - -impl Deref for FlashSectorBuffer { - type Target = [u8; FlashStorage::SECTOR_SIZE as usize]; - - fn deref(&self) -> &Self::Target { - &self.data - } -} - -impl DerefMut for FlashSectorBuffer { - fn deref_mut(&mut self) -> &mut Self::Target { - &mut self.data - } -} +use crate::{buffer::*, chip_specific}; #[derive(Debug)] #[non_exhaustive] @@ -71,8 +50,9 @@ impl FlashStorage { #[cfg(any(feature = "esp32", feature = "esp32s2"))] const ADDR: u32 = 0x1000; - let mut buffer = [0u8; 8]; - storage.internal_read(ADDR, &mut buffer).ok(); + let mut buffer = FlashWordBuffer::uninit(); + storage.internal_read(ADDR, buffer.as_bytes_mut()).unwrap(); + let buffer = unsafe { buffer.assume_init_bytes() }; let mb = match buffer[3] & 0xf0 { 0x00 => 1, 0x10 => 2, @@ -115,11 +95,11 @@ impl FlashStorage { pub(crate) fn internal_read( &mut self, offset: u32, - bytes: &mut [u8], + bytes: &mut [MaybeUninit], ) -> Result<(), FlashStorageError> { check_rc(chip_specific::esp_rom_spiflash_read( offset, - bytes.as_ptr() as *mut u32, + bytes.as_mut_ptr() as *mut u32, bytes.len() as u32, )) } diff --git a/esp-storage/src/lib.rs b/esp-storage/src/lib.rs index 7247ab8c231..16a8cf3f9b7 100644 --- a/esp-storage/src/lib.rs +++ b/esp-storage/src/lib.rs @@ -30,7 +30,7 @@ mod chip_specific; mod common; #[cfg(any(feature = "storage", feature = "nor-flash"))] -use common::FlashSectorBuffer; +mod buffer; #[cfg(any(feature = "storage", feature = "nor-flash"))] pub use common::{FlashStorage, FlashStorageError}; diff --git a/esp-storage/src/nor_flash.rs b/esp-storage/src/nor_flash.rs index 16190bc8eea..8d37b1cc25f 100644 --- a/esp-storage/src/nor_flash.rs +++ b/esp-storage/src/nor_flash.rs @@ -1,5 +1,3 @@ -use core::mem::MaybeUninit; - use embedded_storage::nor_flash::{ ErrorType, NorFlash, @@ -8,31 +6,13 @@ use embedded_storage::nor_flash::{ ReadNorFlash, }; -use crate::{FlashSectorBuffer, FlashStorage, FlashStorageError}; - -#[cfg(feature = "bytewise-read")] -#[repr(C, align(4))] -struct FlashWordBuffer { - // NOTE: Ensure that no unaligned fields are added above `data` to maintain its required - // alignment - data: [u8; FlashStorage::WORD_SIZE as usize], -} - #[cfg(feature = "bytewise-read")] -impl core::ops::Deref for FlashWordBuffer { - type Target = [u8; FlashStorage::WORD_SIZE as usize]; - - fn deref(&self) -> &Self::Target { - &self.data - } -} - -#[cfg(feature = "bytewise-read")] -impl core::ops::DerefMut for FlashWordBuffer { - fn deref_mut(&mut self) -> &mut Self::Target { - &mut self.data - } -} +use crate::buffer::{uninit_slice_mut, FlashWordBuffer}; +use crate::{ + buffer::{uninit_slice, FlashSectorBuffer}, + FlashStorage, + FlashStorageError, +}; impl FlashStorage { #[inline(always)] @@ -71,13 +51,13 @@ impl ReadNorFlash for FlashStorage { let (offset, bytes) = { let byte_offset = (offset % Self::WORD_SIZE) as usize; if byte_offset > 0 { - let mut word_buffer = MaybeUninit::::uninit(); - let word_buffer = unsafe { word_buffer.assume_init_mut() }; + let mut word_buffer = FlashWordBuffer::uninit(); let offset = offset - byte_offset as u32; - let length = bytes.len().min(word_buffer.len() - byte_offset); + let length = bytes.len().min(Self::WORD_SIZE as usize - byte_offset); - self.internal_read(offset, &mut word_buffer[..])?; + self.internal_read(offset, word_buffer.as_bytes_mut())?; + let word_buffer = unsafe { word_buffer.assume_init_bytes_mut() }; bytes[..length].copy_from_slice(&word_buffer[byte_offset..][..length]); (offset + Self::WORD_SIZE, &mut bytes[length..]) @@ -94,7 +74,7 @@ impl ReadNorFlash for FlashStorage { { // Chunk already is word aligned so we can read directly to it #[cfg(not(feature = "bytewise-read"))] - self.internal_read(offset, chunk)?; + self.internal_read(offset, uninit_slice(chunk))?; #[cfg(feature = "bytewise-read")] { @@ -102,22 +82,21 @@ impl ReadNorFlash for FlashStorage { let byte_length = length % Self::WORD_SIZE as usize; let length = length - byte_length; - self.internal_read(offset, &mut chunk[..length])?; + self.internal_read(offset, &mut uninit_slice_mut(chunk)[..length])?; // Read not aligned rest of data if byte_length > 0 { - let mut word_buffer = MaybeUninit::::uninit(); - let word_buffer = unsafe { word_buffer.assume_init_mut() }; + let mut word_buffer = FlashWordBuffer::uninit(); - self.internal_read(offset + length as u32, &mut word_buffer[..])?; + self.internal_read(offset + length as u32, word_buffer.as_bytes_mut())?; + let word_buffer = unsafe { word_buffer.assume_init_bytes_mut() }; chunk[length..].copy_from_slice(&word_buffer[..byte_length]); } } } } else { // Bytes buffer isn't word-aligned so we might read only via aligned buffer - let mut buffer = MaybeUninit::::uninit(); - let buffer = unsafe { buffer.assume_init_mut() }; + let mut buffer = FlashSectorBuffer::uninit(); for (offset, chunk) in (offset..) .step_by(Self::SECTOR_SIZE as _) @@ -125,7 +104,7 @@ impl ReadNorFlash for FlashStorage { { // Read to temporary buffer first (chunk length is aligned) #[cfg(not(feature = "bytewise-read"))] - self.internal_read(offset, &mut buffer[..chunk.len()])?; + self.internal_read(offset, &mut buffer.as_bytes_mut()[..chunk.len()])?; // Read to temporary buffer first (chunk length is not aligned) #[cfg(feature = "bytewise-read")] @@ -138,9 +117,11 @@ impl ReadNorFlash for FlashStorage { length }; - self.internal_read(offset, &mut buffer[..length])?; + self.internal_read(offset, &mut buffer.as_bytes_mut()[..length])?; } + let buffer = unsafe { buffer.assume_init_bytes() }; + // Copy to bytes buffer chunk.copy_from_slice(&buffer[..chunk.len()]); } @@ -173,17 +154,16 @@ impl NorFlash for FlashStorage { } } else { // Bytes buffer isn't word-aligned so we might write only via aligned buffer - let mut buffer = MaybeUninit::::uninit(); - let buffer = unsafe { buffer.assume_init_mut() }; + let mut buffer = FlashSectorBuffer::uninit(); for (offset, chunk) in (offset..) .step_by(Self::SECTOR_SIZE as _) .zip(bytes.chunks(Self::SECTOR_SIZE as _)) { // Copy to temporary buffer first - buffer[..chunk.len()].copy_from_slice(chunk); + buffer.as_bytes_mut()[..chunk.len()].copy_from_slice(uninit_slice(chunk)); // Write from temporary buffer - self.internal_write(offset, &buffer[..chunk.len()])?; + self.internal_write(offset, chunk)?; } } diff --git a/esp-storage/src/storage.rs b/esp-storage/src/storage.rs index b1b5c614a0f..f8a03c15db8 100644 --- a/esp-storage/src/storage.rs +++ b/esp-storage/src/storage.rs @@ -1,8 +1,8 @@ -use core::mem::MaybeUninit; +use core::mem::{self, MaybeUninit}; use embedded_storage::{ReadStorage, Storage}; -use crate::{FlashSectorBuffer, FlashStorage, FlashStorageError}; +use crate::{buffer::FlashSectorBuffer, FlashStorage, FlashStorageError}; impl ReadStorage for FlashStorage { type Error = FlashStorageError; @@ -14,8 +14,7 @@ impl ReadStorage for FlashStorage { let mut aligned_offset = offset - data_offset; // Bypass clearing sector buffer for performance reasons - let mut sector_data = MaybeUninit::::uninit(); - let sector_data = unsafe { sector_data.assume_init_mut() }; + let mut sector_data = FlashSectorBuffer::uninit(); while !bytes.is_empty() { let len = bytes.len().min((Self::SECTOR_SIZE - data_offset) as _); @@ -24,8 +23,13 @@ impl ReadStorage for FlashStorage { & !(Self::WORD_SIZE - 1) as usize; // Read only needed data words - self.internal_read(aligned_offset, &mut sector_data[..aligned_end])?; + self.internal_read( + aligned_offset, + &mut sector_data.as_bytes_mut()[..aligned_end], + )?; + let sector_data = §or_data.as_bytes()[..aligned_end]; + let sector_data = unsafe { mem::transmute::<&[MaybeUninit], &[u8]>(sector_data) }; bytes[..len].copy_from_slice(§or_data[data_offset as usize..][..len]); aligned_offset += Self::SECTOR_SIZE; @@ -52,17 +56,17 @@ impl Storage for FlashStorage { let mut aligned_offset = offset - data_offset; // Bypass clearing sector buffer for performance reasons - let mut sector_data = MaybeUninit::::uninit(); - let sector_data = unsafe { sector_data.assume_init_mut() }; + let mut sector_data = FlashSectorBuffer::uninit(); while !bytes.is_empty() { - self.internal_read(aligned_offset, &mut sector_data[..])?; + self.internal_read(aligned_offset, sector_data.as_bytes_mut())?; + let sector_data = unsafe { sector_data.assume_init_bytes_mut() }; let len = bytes.len().min((Self::SECTOR_SIZE - data_offset) as _); sector_data[data_offset as usize..][..len].copy_from_slice(&bytes[..len]); self.internal_erase(aligned_offset / Self::SECTOR_SIZE)?; - self.internal_write(aligned_offset, §or_data[..])?; + self.internal_write(aligned_offset, sector_data)?; aligned_offset += Self::SECTOR_SIZE; data_offset = 0;