#define OS_ERRNO_HWI_ALREADY_CREATED   LOS_ERRNO_OS_ERROR(LOS_MOD_HWI, 0x04)

Hardware interrupt error code: The interrupt has already been created.

Value: 0x02000904

Solution: Check whether the interrupt specified by the passed-in interrupt number has already been created.

在文件los_hwi.h222行定义。