Re: [PATCH] soundwire: qcom: wait for fifo space to be available before read/write

+static int swrm_wait_for_rd_fifo_avail(struct qcom_swrm_ctrl *swrm) +{

• u32 fifo_outstanding_cmd, value;
• u8 fifo_retry_count = SWR_OVERFLOW_RETRY_COUNT;
• /* Check for fifo underflow during read */
• swrm->reg_read(swrm, SWRM_CMD_FIFO_STATUS, &value);
• fifo_outstanding_cmd = FIELD_GET(SWRM_RD_CMD_FIFO_CNT_MASK, value);

• /* Check number of outstanding commands in fifo before read */
  

• if (fifo_outstanding_cmd)

• return 0;
  

• do {

• usleep_range(500, 510);
  

• swrm->reg_read(swrm, SWRM_CMD_FIFO_STATUS, &value);
  

• fifo_outstanding_cmd = FIELD_GET(SWRM_RD_CMD_FIFO_CNT_MASK, value);
  

• if (fifo_outstanding_cmd > 0)
  

• 	break;
  

• } while (fifo_retry_count--);
• if (fifo_outstanding_cmd == 0) {

• dev_err_ratelimited(swrm->dev, "%s err read underflow\n", __func__);
  

• return -ENOMEM;
  

• }
• return 0;

+}

+static int swrm_wait_for_wr_fifo_avail(struct qcom_swrm_ctrl *swrm) +{

• u32 fifo_outstanding_cmd, value;
• u8 fifo_retry_count = SWR_OVERFLOW_RETRY_COUNT;
• /* Check for fifo overflow during write */
• swrm->reg_read(swrm, SWRM_CMD_FIFO_STATUS, &value);
• fifo_outstanding_cmd = FIELD_GET(SWRM_WR_CMD_FIFO_CNT_MASK, value);
• /* Check number of outstanding commands in fifo before write */
• if (fifo_outstanding_cmd != swrm->wr_fifo_depth)

• return 0;
  

• do {

• usleep_range(500, 510);
  

• swrm->reg_read(swrm, SWRM_CMD_FIFO_STATUS, &value);
  

• fifo_outstanding_cmd = FIELD_GET(SWRM_WR_CMD_FIFO_CNT_MASK, value);
  

• if (fifo_outstanding_cmd < swrm->wr_fifo_depth)
  

• 	break;
  

• } while (fifo_retry_count--);
• if (fifo_outstanding_cmd == swrm->wr_fifo_depth) {

• dev_err_ratelimited(swrm->dev, "%s err write overflow\n", __func__);
  

• return -ENOMEM;
  

• }
• return 0;

+}

nit-pick: you could merge the prologue and loop body with a while(fifo_retry_count--) and put the usleep_range() at the end of the loop.