Re: [PATCH] bus: mhi: Fix channel close issue on driver remove

[Bhaumik Bhatt <bbhatt@codeaurora.org>]

On 2020-10-09 02:07, Loic Poulain wrote:
> Some MHI device drivers need to stop the channels in their driver
> remove callback (e.g. module unloading), but the unprepare function
> is aborted because MHI core moved the channels to suspended state
> prior calling driver remove callback. This prevents the driver to
> send a proper MHI RESET CHAN command to the device. Device is then
> unaware of the stopped state of these channels.
> 
> This causes issue when driver tries to start the channels again (e.g.
> module is reloaded), since device considers channels as already
> started (inconsistent state).
> 
> Fix this by allowing channel reset when channel is suspended.
> 
> Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
> ---
>  drivers/bus/mhi/core/main.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
> index d20967a..a588eac 100644
> --- a/drivers/bus/mhi/core/main.c
> +++ b/drivers/bus/mhi/core/main.c
> @@ -1232,7 +1232,8 @@ static void __mhi_unprepare_channel(struct
> mhi_controller *mhi_cntrl,
>  	/* no more processing events for this channel */
>  	mutex_lock(&mhi_chan->mutex);
>  	write_lock_irq(&mhi_chan->lock);
> -	if (mhi_chan->ch_state != MHI_CH_STATE_ENABLED) {
> +	if (mhi_chan->ch_state != MHI_CH_STATE_ENABLED &&
> +	    mhi_chan->ch_state != MHI_CH_STATE_SUSPENDED) {
>  		write_unlock_irq(&mhi_chan->lock);
>  		mutex_unlock(&mhi_chan->mutex);
>  		return;

Thanks,
Bhaumik
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