Disk

Author: Hunter Ross @hunteross

SD Card Driver

Source: /crates/kernel/src/device/sdcard.rs

This driver was initially developed with hardware in mind and thus was ported from another bare metal Raspberry Pi project

The SD Card initializes correctly on hardware w/out issue and only minor changes are needed to initialize on QEMU. For R/W on QEMU some other minor changes are needed. These can be seen on the branch ext2-sd-test.

API

read(&mut self, buf: &mut [u8]) -> Result<u32, SdCardError>

Reads bytes from its current offset into buf. Mostly used interally and read_sector is preferred. Returns bytes read or SdCardError.

write(&mut self, buf: &[u8]) -> Result<u32, SdCardError>

Writes bytes from buf to its current offset. Mostly used internally and write_sector is preferred. Returns bytes written or SdCardError.

seek(&mut self, offset: u64) -> u64

Changes the current block offset. Returns the offset value.

get_capacity(&self) -> u64

Returns the capacity of the SD Card.

get_block_size(&self) -> u32

Returns the block size of the SD Card. Should be 512?

get_id(&self) -> &[u32; 4]

Returns the id of the card.

The following functions are used to implement the `BlockDevice` trait for the SD Card Driver and are preferred over `read()` and `write()`.

read_sector(&mut self, index: u64, buffer: &mut [u8; filesystem::SECTOR_SIZE],) -> Result<(), filesystem::BlockDeviceError>

Reads a sector’s worth of bytes from offset: index into buf.

write_sector(&mut self, index: u64, buffer: &[u8; filesystem::SECTOR_SIZE],) -> Result<(), filesystem::BlockDeviceError>

Writes a sector’s worth of bytes from buf to offset: index.

read_sectors(&mut self, index: u64, buffer: &mut [u8],) -> Result<(), filesystem::BlockDeviceError>

Reads multiple sectors worth of bytes from offset: index into buf.

Note: buf must be a multiple of the block size

write_sectors(&mut self, index: u64, buffer: &[u8],) -> Result<(), filesystem::BlockDeviceError>

Writes multiple sectors worth of bytes from buf to offset: index.