Two related changes to make device identities legible in the boot log and in
the code that matches on them.
Logging: the pci-bus driver decodes each function's class/subclass/prog-IF
triple to human names (via the existing pci-class module), and the acpi
service appends each _HID's human name (via acpi-ids) to its report line. So
"class 0x01 (Mass Storage Controller) subclass 0x06 (Serial ATA Controller)
progif 0x01 (AHCI 1.0)" reads straight off the log when writing a driver.
Naming: a new coding standard ("Named values, not magic numbers") says a value
with meaning gets a name, prefer an enum for value sets. Applied:
- pci-class is refactored from u8-switch tables into a BaseClass enum plus
per-class SubClass/ProgIf enums with name() methods (the usb-ids shape). The
public className/subclassName/progIfName(u8...) API is unchanged, so the
hardware-byte decoders (pci-bus, the kernel dump) are untouched; output is
byte-identical.
- the device-manager builds the xHCI class triple from named parts instead of
a bare 0x0C0330.
- the acpi service's _CRS walk names its resource-descriptor tags as
SmallResourceType/LargeResourceType enums, and the _HID integer decode uses
the AML module's existing *_opcode constants (now re-exported from aml.zig)
rather than bare 0x0A/0xFF/... literals.
`pci_device` alone says nothing — an ISA bridge, an AHCI controller, and an xHCI USB
controller are all just `pci_device` by DeviceClass. The identity lives in the 24-bit
class code (base class / subclass / prog-IF) that discovery already recorded in
ids.pci_class but the dump threw away.
New system/devices/pci-class.zig (module `pci-class`): pure reference data from the PCI
spec (per the OSDev PCI table) decoding the triple into names — className, subclassName,
progIfName, plus ClassCode.unpack. No hardware access, so it's shared by kernel
discovery and any future user-space PCI tool. device_tree.dump now prints, under each
PCI function, its class/subclass/prog-IF as both hex and name:
pci0:00:1f.0 [pci_device]
class 0x06 (Bridge) subclass 0x01 (ISA Bridge) progif 0x00
pci0:00:1f.2 [pci_device]
class 0x01 (Mass Storage Controller) subclass 0x06 (Serial ATA Controller) progif 0x01 (AHCI 1.0)
Host test covers the decoder (bridge/AHCI/xHCI, the "Other" 0x80 convention, unknowns).
Suite 41/41 plus host tests.
Daniel Samson