VORTEX_ADB_SR
hwwrite(vortex->mmio, VORTEX_ADB_SR, 0);
hwwrite(vortex->mmio, VORTEX_ADB_SR,
hwread(vortex->mmio, VORTEX_ADB_SR) | (0x1 << channel));
hwwrite(vortex->mmio, VORTEX_ADB_SR,
hwread(vortex->mmio, VORTEX_ADB_SR) & ~(0x1 << channel));