disks: Add MMC detection

Signed-off-by: Ikey Doherty <[email protected]>

crates/disks/src/disk.rs

@@ -9,13 +9,15 @@ use std::{
     path::{Path, PathBuf},
 };
 
-use crate::{nvme, partition::Partition, scsi, sysfs, DEVFS_DIR};
+use crate::{mmc, nvme, partition::Partition, scsi, sysfs, DEVFS_DIR};
 
 /// Represents the type of disk device.
 #[derive(Debug)]
 pub enum Disk {
     /// SCSI disk device (e.g. sda, sdb)
     Scsi(scsi::Disk),
+    /// MMC disk device (e.g. mmcblk0)
+    Mmc(mmc::Disk),
     /// NVMe disk device (e.g. nvme0n1)
     Nvme(nvme::Disk),
 }
@@ -26,8 +28,9 @@ impl Deref for Disk {
     // Let scsi and nvme disks deref to BasicDisk
     fn deref(&self) -> &Self::Target {
         match self {
-            Disk::Scsi(disk) => disk,
+            Disk::Mmc(disk) => disk,
             Disk::Nvme(disk) => disk,
+            Disk::Scsi(disk) => disk,
         }
     }
 }

crates/disks/src/lib.rs

@@ -6,6 +6,7 @@ mod disk;
 use std::{fs, io, path::PathBuf};
 
 pub use disk::*;
+pub mod mmc;
 pub mod nvme;
 pub mod partition;
 pub mod scsi;
@@ -58,6 +59,8 @@ impl BlockDevice {
                 Disk::Scsi(disk)
             } else if let Some(disk) = nvme::Disk::from_sysfs_path(&sysfs_dir, &entry) {
                 Disk::Nvme(disk)
+            } else if let Some(disk) = mmc::Disk::from_sysfs_path(&sysfs_dir, &entry) {
+                Disk::Mmc(disk)
             } else {
                 continue;
             };

crates/disks/src/mmc.rs

@@ -0,0 +1,48 @@
+// SPDX-FileCopyrightText: Copyright © 2025 Serpent OS Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+//! MMC device enumeration and handling
+//!
+//! This module provides functionality to enumerate and handle MMC (MultiMediaCard)
+//! storage devices by parsing sysfs paths and device names.
+
+use crate::{BasicDisk, DiskInit};
+use regex::Regex;
+use std::{ops::Deref, path::Path, sync::OnceLock};
+
+/// Regex pattern to match valid MMC device names (e.g. mmcblk0)
+static MMC_PATTERN: OnceLock<Regex> = OnceLock::new();
+
+/// Represents an MMC disk device
+#[derive(Debug)]
+pub struct Disk(pub BasicDisk);
+
+impl Deref for Disk {
+    type Target = BasicDisk;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl DiskInit for Disk {
+    /// Creates a new MMC disk from a sysfs path and device name
+    ///
+    /// # Arguments
+    /// * `sysroot` - The sysfs root path
+    /// * `name` - The device name to check
+    ///
+    /// # Returns
+    /// * `Some(Disk)` if the device name matches MMC pattern
+    /// * `None` if name doesn't match or basic disk creation fails
+    fn from_sysfs_path(sysroot: &Path, name: &str) -> Option<Self> {
+        let regex =
+            MMC_PATTERN.get_or_init(|| Regex::new(r"^mmcblk\d+$").expect("Failed to initialise known-working regex"));
+        if regex.is_match(name) {
+            Some(Self(BasicDisk::from_sysfs_path(sysroot, name)?))
+        } else {
+            None
+        }
+    }
+}