usb_selftest_mlun Directory Reference

Directory dependency graph for usb_selftest_mlun:

Directories
	inc
	src

Detailed Description

Brings up a multi-LUN USB Mass-Storage device and verifies it against itself on-chip – no PC in the loop. The two USB ports are cabled to each other and one image runs both USB stacks. USBFS (J11) exposes two read-only raw block logical units in a single device, each synthesizing a deterministic per-(LUN, LBA) byte pattern in media_read; USBHS (J7) is the polled first-party host stack (ra8_usb_hmsc), which reads GET_MAX_LUN and then sweeps each LUN with READ_CAPACITY plus a full raw multi-block READ(10), recomputing the same formula to check every sector.

No filesystem is involved, so this is a pure read-path test of whether the host addresses each logical unit independently. Because the two LUNs synthesize distinct data with no shared backing, an addressing bug cannot hide behind identical bytes.

Why two LUNs

The vendored USBX Cortex-M33 port defaults UX_MAX_SLAVE_LUN to 1, and that value sizes the storage class's LUN arrays – a device declaring more LUNs than the cap overruns the parameter struct. cmake/usbx.cmake raises the cap tree-wide so the Mass-Storage class can expose more than one unit. Two is the smallest genuinely-multi-LUN device and is enough to exercise per-LUN addressing on both sides; single-LUN apps are unaffected, using LUN 0 of a slightly larger array.

The s_dbg_* globals publish phase, LUNs verified, the reported GET_MAX_LUN, the first mismatch as lun<<24 | sector, and device-worker progress, for a J-Link readout.

Pinout

FS device: P4_07 VBUS sense, P5_00 VBUSEN GPIO LOW, P8_14/P8_15 data (PSEL usb_fs). HS host: SW4-8 Host via the U15 expander, PD07 HIGH (U18 powers J7), P4_08 VBUS sense (PSEL usb_hs). Console: PD_02/PD_03 SCI8. The device advertises VID 0x1209 with a per-app PID; bench use only.