Red Bear OS
27021d15d3
Implements the first real xHCI transfer recovery behavior after the
36-code status mapping, mirroring the smallest practical subset of
Linux 7.1 drivers/usb/host/xhci-ring.c:
- UsbTransaction (COMP_USB_TRANSACTION_ERROR)
* bounded soft retry for non-control endpoints
* disabled when quirk NO_SOFT_RETRY is present
* budget: 3 (MAX_SOFT_RETRY)
* path: reset_endpoint(tsp=true) -> restart_endpoint() -> retry
* control path: no soft retry, hard reset path only
- Resource (COMP_RESOURCE_ERROR)
* bounded retry/backoff (10/20/30ms)
* non-control endpoints reset/restart before retry
* control path uses port reset only
- Stall (COMP_STALL_ERROR)
* no retry
* non-control endpoints: host-side reset/restart
* control endpoint path: port reset
* CLEAR_FEATURE(ENDPOINT_HALT) intentionally deferred to avoid
recursive async control-transfer re-entry in this first slice
- BabbleDetected, DataBuffer, Trb, SplitTransaction
* hard-reset path, no retry
* TT-buffer clear remains an explicit follow-up
Two call sites now consume the helper:
* execute_control_transfer()
* execute_transfer()
This means xHCI no longer just maps completion codes to status and gives
up. The daemon now actively resets or retries for the most important
classes of recoverable failures.
Cross-reference:
Linux 7.1 drivers/usb/host/xhci-ring.c
- process_bulk_intr_td() soft retry path
- finish_td() hard-reset dispatch
- xhci_halted_host_endpoint() halted-vs-dequeue decision
Drivers
- Libraries
- Services
- Hardware Interfaces
- Devices
- System Interfaces
- System Calls
- Schemes
- Contribution Details
Libraries
- amlserde - Library to provide serialization/deserialization of the AML symbol table from ACPI
- common - Library with shared driver code
- executor - Library to run Rust futures and integrate the executor in an interrupt+queue model without a separated reactor thread
- graphics/console-draw - Library with shared terminal drawing code
- graphics/driver-graphics - Library with shared graphics code
- graphics/graphics-ipc - Library with graphics IPC shared code
- net/driver-network - Library with shared networking code
- storage/partitionlib - Library with MBR and GPT code
- storage/driver-block - Library with shared storage code
- virtio-core - VirtIO driver library
Services
- graphics/fbbootlogd - Daemon for boot log drawing
- graphics/fbcond - Terminal daemon
- hwd - Daemon that handle the ACPI and DeviceTree booting
- inputd - Multiplexes input from multiple input drivers and provides that to Orbital
- pcid-spawner - Daemon for PCI-based device driver spawn
- storage/lived - Daemon for live disk
- redoxerd - Daemon that send/receive terminal text between the host system and QEMU
Hardware Interfaces
- acpid - ACPI interface driver
- pcid - PCI and PCI Express driver
Devices
CPU
- rtcd - x86 Real Time Clock driver
Controllers
- usb/xhcid - xHCI USB controller driver
Storage
- storage/ahcid - AHCI (SATA) driver
- storage/bcm2835-sdhcid - BCM2835 storage driver
- storage/ided - PATA (IDE) driver
- storage/nvmed - NVMe driver
- storage/virtio-blkd - VirtIO block device driver
- storage/usbscsid - USB SCSI driver
Graphics
- graphics/ihdgd - Intel graphics driver
- graphics/vesad - VESA video driver
- graphics/virtio-gpud - VirtIO-GPU device driver
Input
- input/ps2d - PS/2 interface driver
- input/usbhidd - USB HID driver
- usb/usbhubd - USB Hub driver
- usb/usbctl - TODO
Sound
- audio/ac97d - AC'97 codec driver
- audio/ihdad - Intel HD Audio chipset driver
- audio/sb16d - Sound Blaster sound card driver
Networking
- net/e1000d - Intel Gigabit ethernet driver
- net/ixgbed - Intel 10 Gigabit ethernet driver
- net/rtl8139d, net/rtl8168d - Realtek ethernet drivers
- net/virtio-netd - VirtIO network device driver
Virtualization
- vboxd - VirtualBox driver
Some drivers are work-in-progress and incomplete, read this tracking issue to verify.
System Interfaces
This section explain the system interfaces used by drivers.
System Calls
iopl: system call that sets the I/O privilege level. x86 has four privilege rings (0/1/2/3), of which the kernel runs in ring 0 and userspace in ring 3. IOPL can only be changed by the kernel, for obvious security reasons, and therefore the Redox kernel needs root to set it. It is unique for each process. Processes with IOPL=3 can access I/O ports, and the kernel can access them as well.
Schemes
/scheme/memory/physical: Allows mapping physical memory frames to driver-accessible virtual memory pages, with various available memory types:/scheme/memory/physical: Default memory type (currently writeback)/scheme/memory/physical@wbWriteback cached memory/scheme/memory/physical@uc: Uncacheable memory/scheme/memory/physical@wc: Write-combining memory
/scheme/irq: Allows getting events from interrupts. It is used primarily by listening for its file descriptors using the/scheme/eventscheme.
Contribution Details
Driver Design
A device driver on Redox is an user-space daemon that use system calls and schemes to work, while operating systems with monolithic kernels drivers use internal kernel APIs instead of common program APIs.
If you want to port a driver from a monolithic operating system to Redox you will need to rewrite the driver with reverse enginnering of the code logic, because the logic is adapted to internal kernel APIs (it's a hard task if the device is complex, datasheets are much more easy).
Write a Driver
Datasheets are preferable (much more easy depending on device complexity), when they are freely available. Be aware that datasheets are often provided under a Non-Disclosure Agreement from hardware vendors, which can affect the ability to create an MIT-licensed driver.
If datasheets aren't available you need to do reverse-engineering of BSD or Linux drivers (if you want use a Linux driver as reference for your Redox driver please ask in the Chat before the implementation to know/satisfy the license requirements and not waste your time, also if you use a BSD driver not licensed as BSD as reference).
Libraries
You should use the redox-scheme and redox_event libraries to create your drivers, you can also read the example driver or read the code of other drivers with the same type of your device.
Before testing your changes be aware of this.
References
If you want to reverse enginner the existing drivers, you can access the BSD code using these links:
How To Contribute
To learn how to contribute to this system component you need to read the following document:
Development
To learn how to do development with this system component inside the Redox build system you need to read the Build System and Coding and Building pages.
How To Build
To build this system component you need to download the Redox build system, you can learn how to do it on the Building Redox page.
This is necessary because they only work with cross-compilation to a Redox virtual machine or real hardware, but you can do some testing from Linux.