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Date:   Mon, 4 Jan 2021 22:33:59 +0530
From:   Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
To:     Carl Huang <cjhuang@codeaurora.org>
Cc:     hemantk@codeaurora.org, linux-arm-msm@vger.kernel.org,
        linux-kernel@vger.kernel.org, ath11k@lists.infradead.org
Subject: Re: [PATCH v3] mhi: use irq_flags if controller driver configures it
Message-ID: <20210104170359.GE2256@work>
References: <20210104101128.8217-1-cjhuang@codeaurora.org>
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On Mon, Jan 04, 2021 at 06:11:28PM +0800, Carl Huang wrote:
> If controller driver has specified the irq_flags, mhi uses this specified
> irq_flags. Otherwise, mhi uses default irq_flags.
> 
> The purpose of this change is to support one MSI vector for QCA6390.
> MHI will use one same MSI vector too in this scenario.
> 
> In case of one MSI vector, IRQ_NO_BALANCING is needed when irq handler
> is requested. The reason is if irq migration happens, the msi_data may
> change too. However, the msi_data is already programmed to QCA6390
> hardware during initialization phase. This msi_data inconsistence will
> result in crash in kernel.
> 
> Another issue is in case of one MSI vector, IRQF_NO_SUSPEND will trigger
> WARNINGS because QCA6390 wants to disable the IRQ during the suspend.
> 
> To avoid above two issues, QCA6390 driver specifies the irq_flags in case
> of one MSI vector when mhi_register_controller is called.
> 
> Signed-off-by: Carl Huang <cjhuang@codeaurora.org>
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Applied to mhi-next!

Thanks,
Mani

> ---
> v3:
> - replace "client driver" with "controller driver"
> - add Reviewed-by: Manivannan Sadhasivam 
> 
> v2:
> - document irq_flags added to mhi_controller
> 
>  drivers/bus/mhi/core/init.c | 9 +++++++--
>  include/linux/mhi.h         | 2 ++
>  2 files changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
> index 381fdea..37903a8 100644
> --- a/drivers/bus/mhi/core/init.c
> +++ b/drivers/bus/mhi/core/init.c
> @@ -148,12 +148,17 @@ int mhi_init_irq_setup(struct mhi_controller *mhi_cntrl)
>  {
>  	struct mhi_event *mhi_event = mhi_cntrl->mhi_event;
>  	struct device *dev = &mhi_cntrl->mhi_dev->dev;
> +	unsigned long irq_flags = IRQF_SHARED | IRQF_NO_SUSPEND;
>  	int i, ret;
>  
> +	/* if controller driver has set irq_flags, use it */
> +	if (mhi_cntrl->irq_flags)
> +		irq_flags = mhi_cntrl->irq_flags;
> +
>  	/* Setup BHI_INTVEC IRQ */
>  	ret = request_threaded_irq(mhi_cntrl->irq[0], mhi_intvec_handler,
>  				   mhi_intvec_threaded_handler,
> -				   IRQF_SHARED | IRQF_NO_SUSPEND,
> +				   irq_flags,
>  				   "bhi", mhi_cntrl);
>  	if (ret)
>  		return ret;
> @@ -171,7 +176,7 @@ int mhi_init_irq_setup(struct mhi_controller *mhi_cntrl)
>  
>  		ret = request_irq(mhi_cntrl->irq[mhi_event->irq],
>  				  mhi_irq_handler,
> -				  IRQF_SHARED | IRQF_NO_SUSPEND,
> +				  irq_flags,
>  				  "mhi", mhi_event);
>  		if (ret) {
>  			dev_err(dev, "Error requesting irq:%d for ev:%d\n",
> diff --git a/include/linux/mhi.h b/include/linux/mhi.h
> index cb7cd54..77f1e3f 100644
> --- a/include/linux/mhi.h
> +++ b/include/linux/mhi.h
> @@ -351,6 +351,7 @@ struct mhi_controller_config {
>   * @fbc_download: MHI host needs to do complete image transfer (optional)
>   * @pre_init: MHI host needs to do pre-initialization before power up
>   * @wake_set: Device wakeup set flag
> + * @irq_flags: irq flags passed to request_irq (optional)
>   *
>   * Fields marked as (required) need to be populated by the controller driver
>   * before calling mhi_register_controller(). For the fields marked as (optional)
> @@ -440,6 +441,7 @@ struct mhi_controller {
>  	bool fbc_download;
>  	bool pre_init;
>  	bool wake_set;
> +	unsigned long irq_flags;
>  };
>  
>  /**
> -- 
> 2.7.4
>