On Thu, Apr 01, 2021 at 02:16:14PM -0700, Bhaumik Bhatt wrote:
> MHI host can fail early if device is in a bad state by attempting
> to assert device wake and holding the runtime PM vote before
> sending a channel update command instead of performing a wake
> toggle and waiting for a timeout if the send were to fail. This
> can help improve the design and enable shorter wait periods for
> device to respond as votes are already held.
>
> Signed-off-by: Bhaumik Bhatt <bbhatt@xxxxxxxxxxxxxx>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
Thanks,
Mani
> ---
> drivers/bus/mhi/core/main.c | 19 ++++++++++++++-----
> 1 file changed, 14 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
> index 94fdbf7..989a2a8 100644
> --- a/drivers/bus/mhi/core/main.c
> +++ b/drivers/bus/mhi/core/main.c
> @@ -1278,16 +1278,18 @@ static int mhi_update_channel_state(struct mhi_controller *mhi_cntrl,
> return -EINVAL;
> }
>
> - mhi_cntrl->wake_toggle(mhi_cntrl);
> + /* bring host and device out of suspended states */
> + ret = mhi_device_get_sync(mhi_cntrl->mhi_dev);
> + if (ret)
> + return ret;
> mhi_cntrl->runtime_get(mhi_cntrl);
> - mhi_cntrl->runtime_put(mhi_cntrl);
>
> reinit_completion(&mhi_chan->completion);
> ret = mhi_send_cmd(mhi_cntrl, mhi_chan, cmd);
> if (ret) {
> dev_err(dev, "%d: Failed to send %s channel command\n",
> mhi_chan->chan, TO_CH_STATE_TYPE_STR(to_state));
> - return ret;
> + goto exit_channel_update;
> }
>
> ret = wait_for_completion_timeout(&mhi_chan->completion,
> @@ -1296,9 +1298,12 @@ static int mhi_update_channel_state(struct mhi_controller *mhi_cntrl,
> dev_err(dev,
> "%d: Failed to receive %s channel command completion\n",
> mhi_chan->chan, TO_CH_STATE_TYPE_STR(to_state));
> - return -EIO;
> + ret = -EIO;
> + goto exit_channel_update;
> }
>
> + ret = 0;
> +
> if (to_state != MHI_CH_STATE_TYPE_RESET) {
> write_lock_irq(&mhi_chan->lock);
> mhi_chan->ch_state = (to_state == MHI_CH_STATE_TYPE_START) ?
> @@ -1309,7 +1314,11 @@ static int mhi_update_channel_state(struct mhi_controller *mhi_cntrl,
> dev_dbg(dev, "%d: Channel state change to %s successful\n",
> mhi_chan->chan, TO_CH_STATE_TYPE_STR(to_state));
>
> - return 0;
> +exit_channel_update:
> + mhi_cntrl->runtime_put(mhi_cntrl);
> + mhi_device_put(mhi_cntrl->mhi_dev);
> +
> + return ret;
> }
>
> static void __mhi_unprepare_channel(struct mhi_controller *mhi_cntrl,
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>
