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SubjectRe: [PATCH] mhi: use irq_flags if client driver configures it
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On 12/7/20 7:55 PM, Carl Huang wrote:
> If client 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>
> ---
> drivers/bus/mhi/core/init.c | 9 +++++++--
> include/linux/mhi.h | 1 +
> 2 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
> index 0ffdebd..5f74e1e 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 client driver has set irq_flags, use it */
> + if (mhi_cntrl->irq_flags)
> + irq_flags = mhi_cntrl->irq_flags;
Jeff if i remember correctly your use case also have one dedicated irq
line for all the MSIs, just want to confirm if you are fine with this
change ? i was wondering if any input check is required for irq_flags
passed by controller, or responsibility is on controller for any
undesired behavior. Like passing IRQF_SHARED and IRQF_ONESHOT when one
irq line is shared among multiple MSIs.
> +
> /* 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 d4841e5..f039e58 100644
> --- a/include/linux/mhi.h
> +++ b/include/linux/mhi.h
> @@ -442,6 +442,7 @@ struct mhi_controller {
> bool fbc_download;
> bool pre_init;
> bool wake_set;
> + unsigned long irq_flags;
> };
>
> /**
>

Thanks,
Hemant

--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

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