usb_dmac_chan_read
u32 chcr = usb_dmac_chan_read(chan, USB_DMACHCR);
u32 chcr = usb_dmac_chan_read(chan, USB_DMACHCR);
residue -= usb_dmac_chan_read(chan, USB_DMADAR) - mem_addr;
residue -= usb_dmac_chan_read(chan, USB_DMASAR) - mem_addr;
chcr = usb_dmac_chan_read(chan, USB_DMACHCR);