- if (ep93xx_dma_advance_active(edmac)) {
- edmac->edma->hw_submit(edmac);
- return INTERRUPT_NEXT_BUFFER;
+ if (!last_done &&
+ (buf_fsm == M2M_STATUS_BUF_NO ||
+ buf_fsm == M2M_STATUS_BUF_ON)) {
+ /*
+ * Two buffers are ready for update when Buffer FSM is in
+ * DMA_NO_BUF state. Only one buffer can be prepared without
+ * disabling the channel or polling the DONE bit.
+ * To simplify things, always prepare only one buffer.
+ */
+ if (ep93xx_dma_advance_active(edmac)) {
+ m2m_fill_desc(edmac);
+ if (done && !edmac->chan.private) {
+ /* Software trigger for memcpy channel */
+ control = readl(edmac->regs + M2M_CONTROL);
+ control |= M2M_CONTROL_START;
+ writel(control, edmac->regs + M2M_CONTROL);
+ }
+ return INTERRUPT_NEXT_BUFFER;
+ } else {
+ last_done = true;
+ }
+ }
+
+ /*
+ * Disable the channel only when Buffer FSM is in DMA_NO_BUF state
+ * and Control FSM is in DMA_STALL state.
+ */
+ if (last_done &&
+ buf_fsm == M2M_STATUS_BUF_NO &&
+ ctl_fsm == M2M_STATUS_CTL_STALL) {
+ /* Disable interrupts and the channel */
+ control = readl(edmac->regs + M2M_CONTROL);
+ control &= ~(M2M_CONTROL_DONEINT | M2M_CONTROL_NFBINT
+ | M2M_CONTROL_ENABLE);
+ writel(control, edmac->regs + M2M_CONTROL);
+ return INTERRUPT_DONE;