dcd_lpc17_40: mask USB IRQ around non-reentrant SIE and realization sequences

The SIE command protocol (CmdCode + CCEMPTY/CDFULL handshake), the
slave-mode Ctrl/RxData/TxData window, the EpIntEn read-modify-writes, and
set_ep_size's ReEp/EP_RLZED handshake are all shared between thread-mode
API calls and dcd_int_handler, and none are reentrant: an ISR preempting a
thread-mode sequence consumes its handshake flags or, in set_ep_size's
case, a bus reset's DevIntClr = 0xFFFFFFFF eats the EP_RLZED flag the
spin waits on, hanging it forever. Guard them by masking only the USB IRQ
(nestable, ISR-safe; CMSIS NVIC_DisableIRQ already ends with DSB+ISB).
control_xact keeps the mask across its in_isr=true event push, since
osal_none skips queue locking for in_isr.

Hardening, not a fix for an observed failure: the ea4088 usbtest 30/30 +
HIL 14/14 results were reproduced with and without it. The windows are a
few instructions wide and most exposed on RTOS builds where class drivers
queue transfers from tasks concurrent with the USB IRQ.

0 files changed, 0 insertions, 0 deletions