Re: [PATCH v4 1/1] bus: mhi: host: Move IRQ allocation to controller registration phase

[Qiang Yu]

On 6/23/2022 7:54 PM, Manivannan Sadhasivam wrote:
> On Thu, Jun 23, 2022 at 10:43:03AM +0800, Qiang Yu wrote:
> > During runtime, the MHI endpoint may be powered up/down several times.
> > So instead of allocating and destroying the IRQs all the time, let's just
> > enable/disable IRQs during power up/down.
> >
> > The IRQs will be allocated during mhi_register_controller() and freed
> > during mhi_unregister_controller(). This works well for things like PCI
> > hotplug also as once the PCI device gets removed, the controller will
> > get unregistered. And once it comes back, it will get registered back
> > and even if the IRQ configuration changes (MSI), that will get accounted.
> >
> > Signed-off-by: Qiang Yu <quic_qianyu@xxxxxxxxxxx>
> I thought I already gave my r-o-b. But anyway,
>
> Reviewed-by: Manivannan Sadhasivam <mani@xxxxxxxxxx>
>
> I'll wait for a review from Jeff before applying.
>
> Thanks,
> Mani

I apologize for that. Thanks for your time and patience.

> > ---
> > v3->v4: move mhi_init_irq_setup() above mhi_alloc_device()
> > v2->v3: change commit text and comments.
> > v1->v2: Rewrite commit text. Remove a random change. Use
> >          inline enables.
> >
> >   drivers/bus/mhi/host/init.c | 17 ++++++++++++++++-
> >   drivers/bus/mhi/host/pm.c   | 19 +++++++++++++------
> >   2 files changed, 29 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/bus/mhi/host/init.c b/drivers/bus/mhi/host/init.c
> > index cbb86b2..a1d37da 100644
> > --- a/drivers/bus/mhi/host/init.c
> > +++ b/drivers/bus/mhi/host/init.c
> > @@ -179,6 +179,12 @@ int mhi_init_irq_setup(struct mhi_controller *mhi_cntrl)
> >   				   "bhi", mhi_cntrl);
> >   	if (ret)
> >   		return ret;
> > +	/*
> > +	 * IRQs should be enabled during mhi_async_power_up(), so disable them explicitly here.
> > +	 * Due to the use of IRQF_SHARED flag as default while requesting IRQs, we assume that
> > +	 * IRQ_NOAUTOEN is not applicable.
> > +	 */
> > +	disable_irq(mhi_cntrl->irq[0]);
> >   
> >   	for (i = 0; i < mhi_cntrl->total_ev_rings; i++, mhi_event++) {
> >   		if (mhi_event->offload_ev)
> > @@ -200,6 +206,8 @@ int mhi_init_irq_setup(struct mhi_controller *mhi_cntrl)
> >   				mhi_cntrl->irq[mhi_event->irq], i);
> >   			goto error_request;
> >   		}
> > +
> > +		disable_irq(mhi_cntrl->irq[mhi_event->irq]);
> >   	}
> >   
> >   	return 0;
> > @@ -979,12 +987,16 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
> >   		goto err_destroy_wq;
> >   	}
> >   
> > +	ret = mhi_init_irq_setup(mhi_cntrl);
> > +	if (ret)
> > +		goto err_ida_free;
> > +
> >   	/* Register controller with MHI bus */
> >   	mhi_dev = mhi_alloc_device(mhi_cntrl);
> >   	if (IS_ERR(mhi_dev)) {
> >   		dev_err(mhi_cntrl->cntrl_dev, "Failed to allocate MHI device\n");
> >   		ret = PTR_ERR(mhi_dev);
> > -		goto err_ida_free;
> > +		goto error_setup_irq;
> >   	}
> >   
> >   	mhi_dev->dev_type = MHI_DEVICE_CONTROLLER;
> > @@ -1007,6 +1019,8 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
> >   
> >   err_release_dev:
> >   	put_device(&mhi_dev->dev);
> > +error_setup_irq:
> > +	mhi_deinit_free_irq(mhi_cntrl);
> >   err_ida_free:
> >   	ida_free(&mhi_controller_ida, mhi_cntrl->index);
> >   err_destroy_wq:
> > @@ -1027,6 +1041,7 @@ void mhi_unregister_controller(struct mhi_controller *mhi_cntrl)
> >   	struct mhi_chan *mhi_chan = mhi_cntrl->mhi_chan;
> >   	unsigned int i;
> >   
> > +	mhi_deinit_free_irq(mhi_cntrl);
> >   	mhi_destroy_debugfs(mhi_cntrl);
> >   
> >   	destroy_workqueue(mhi_cntrl->hiprio_wq);
> > diff --git a/drivers/bus/mhi/host/pm.c b/drivers/bus/mhi/host/pm.c
> > index dc2e8ff..4a42186 100644
> > --- a/drivers/bus/mhi/host/pm.c
> > +++ b/drivers/bus/mhi/host/pm.c
> > @@ -500,7 +500,7 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl)
> >   	for (i = 0; i < mhi_cntrl->total_ev_rings; i++, mhi_event++) {
> >   		if (mhi_event->offload_ev)
> >   			continue;
> > -		free_irq(mhi_cntrl->irq[mhi_event->irq], mhi_event);
> > +		disable_irq(mhi_cntrl->irq[mhi_event->irq]);
> >   		tasklet_kill(&mhi_event->task);
> >   	}
> >   
> > @@ -1060,12 +1060,13 @@ static void mhi_deassert_dev_wake(struct mhi_controller *mhi_cntrl,
> >   
> >   int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
> >   {
> > +	struct mhi_event *mhi_event = mhi_cntrl->mhi_event;
> >   	enum mhi_state state;
> >   	enum mhi_ee_type current_ee;
> >   	enum dev_st_transition next_state;
> >   	struct device *dev = &mhi_cntrl->mhi_dev->dev;
> >   	u32 interval_us = 25000; /* poll register field every 25 milliseconds */
> > -	int ret;
> > +	int ret, i;
> >   
> >   	dev_info(dev, "Requested to power ON\n");
> >   
> > @@ -1117,9 +1118,15 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
> >   		mhi_write_reg(mhi_cntrl, mhi_cntrl->bhi, BHI_INTVEC, 0);
> >   	}
> >   
> > -	ret = mhi_init_irq_setup(mhi_cntrl);
> > -	if (ret)
> > -		goto error_exit;
> > +	/* IRQs have been requested during probe, so we just need to enable them. */
> > +	enable_irq(mhi_cntrl->irq[0]);
> > +
> > +	for (i = 0; i < mhi_cntrl->total_ev_rings; i++, mhi_event++) {
> > +		if (mhi_event->offload_ev)
> > +			continue;
> > +
> > +		enable_irq(mhi_cntrl->irq[mhi_event->irq]);
> > +	}
> >   
> >   	/* Transition to next state */
> >   	next_state = MHI_IN_PBL(current_ee) ?
> > @@ -1182,7 +1189,7 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
> >   	/* Wait for shutdown to complete */
> >   	flush_work(&mhi_cntrl->st_worker);
> >   
> > -	free_irq(mhi_cntrl->irq[0], mhi_cntrl);
> > +	disable_irq(mhi_cntrl->irq[0]);
> >   }
> >   EXPORT_SYMBOL_GPL(mhi_power_down);
> >   
> > --
> > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.