On 2/9/23 07:13, Srinivas Kandagatla wrote:
> Wait for Fifo to be empty before going to suspend or before bank
> switch happens. Just to make sure that all the reads/writes are done.
For the suspend case that seems like a valid approach, but for bank
switch don't we already have a bus->msg_lock mutex that will prevent the
bank switch command from being sent before the other commands are handled?
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> ---
> drivers/soundwire/qcom.c | 29 +++++++++++++++++++++++++++++
> 1 file changed, 29 insertions(+)
>
> diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c
> index b2363839624c..465b2a2ef0d5 100644
> --- a/drivers/soundwire/qcom.c
> +++ b/drivers/soundwire/qcom.c
> @@ -325,6 +325,32 @@ static int swrm_wait_for_wr_fifo_avail(struct qcom_swrm_ctrl *swrm)
> return 0;
> }
>
> +static bool swrm_wait_for_wr_fifo_done(struct qcom_swrm_ctrl *swrm)
> +{
> + u32 fifo_outstanding_cmds, value;
> + int fifo_retry_count = SWR_OVERFLOW_RETRY_COUNT;
> +
> + /* Check for fifo overflow during write */
> + swrm->reg_read(swrm, SWRM_CMD_FIFO_STATUS, &value);
> + fifo_outstanding_cmds = FIELD_GET(SWRM_WR_CMD_FIFO_CNT_MASK, value);
> +
> + if (fifo_outstanding_cmds) {
> + while (fifo_retry_count) {
> + usleep_range(500, 510);
> + swrm->reg_read(swrm, SWRM_CMD_FIFO_STATUS, &value);
> + fifo_outstanding_cmds = FIELD_GET(SWRM_WR_CMD_FIFO_CNT_MASK, value);
> + fifo_retry_count--;
> + if (fifo_outstanding_cmds == 0)
> + return true;
> + }
> + } else {
> + return true;
> + }
> +
> +
> + return false;
> +}
> +
> static int qcom_swrm_cmd_fifo_wr_cmd(struct qcom_swrm_ctrl *swrm, u8 cmd_data,
> u8 dev_addr, u16 reg_addr)
> {
> @@ -356,6 +382,7 @@ static int qcom_swrm_cmd_fifo_wr_cmd(struct qcom_swrm_ctrl *swrm, u8 cmd_data,
> usleep_range(150, 155);
>
> if (cmd_id == SWR_BROADCAST_CMD_ID) {
> + swrm_wait_for_wr_fifo_done(swrm);
> /*
> * sleep for 10ms for MSM soundwire variant to allow broadcast
> * command to complete.
> @@ -1122,6 +1149,7 @@ static void qcom_swrm_shutdown(struct snd_pcm_substream *substream,
> {
> struct qcom_swrm_ctrl *ctrl = dev_get_drvdata(dai->dev);
>
> + swrm_wait_for_wr_fifo_done(ctrl);
> sdw_release_stream(ctrl->sruntime[dai->id]);
> ctrl->sruntime[dai->id] = NULL;
> pm_runtime_mark_last_busy(ctrl->dev);
> @@ -1558,6 +1586,7 @@ static int __maybe_unused swrm_runtime_suspend(struct device *dev)
> struct qcom_swrm_ctrl *ctrl = dev_get_drvdata(dev);
> int ret;
>
> + swrm_wait_for_wr_fifo_done(ctrl);
> if (!ctrl->clock_stop_not_supported) {
> /* Mask bus clash interrupt */
> ctrl->intr_mask &= ~SWRM_INTERRUPT_STATUS_MASTER_CLASH_DET;
