This patch adds driver for Ultrasoc SMB(System Memory Buffer)
device. SMB provides a way to buffer messages from ETM, and
store these CPU instructions in system memory.
SMB is developed by Ultrasoc technology, which is acquired by
Siemens, and we still use "Ultrasoc" to name driver.
Signed-off-by: Qi Liu <liuqi115@xxxxxxxxxx>
Tested-by: JunHao He <hejunhao2@xxxxxxxxxxxxx>