diff mbox series

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

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 | expand

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>
diff mbox series

Patch

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,