[v8,5/9] bus: mhi: core: Hold device wake for channel update commands
diff mbox series

Message ID 1617311778-1254-6-git-send-email-bbhatt@codeaurora.org
State Accepted
Commit 73b7aebcc8cbc2cddfb34be9840542807ad61044
Headers show
Series
  • [v8,1/9] bus: mhi: core: Allow sending the STOP channel command
Related show

Commit Message

Bhaumik Bhatt April 1, 2021, 9:16 p.m. UTC
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@codeaurora.org>
---
 drivers/bus/mhi/core/main.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

Comments

Manivannan Sadhasivam April 7, 2021, 6:31 a.m. UTC | #1
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@codeaurora.org>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

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
>
Jeffrey Hugo May 4, 2021, 5:46 p.m. UTC | #2
On 4/1/2021 3:16 PM, 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@codeaurora.org>
> ---

Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>

Patch
diff mbox series

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,