Date:   Thu, 23 Jun 2022 20:49:00 +0800
From:   Qiang Yu <quic_qianyu@...cinc.com>
To:     Manivannan Sadhasivam <mani@...nel.org>
CC:     <quic_hemantk@...cinc.com>, <loic.poulain@...aro.org>,
        <quic_jhugo@...cinc.com>, <mhi@...ts.linux.dev>,
        <linux-arm-msm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <quic_cang@...cinc.com>
Subject: Re: [PATCH v4 1/1] bus: mhi: host: Move IRQ allocation to controller
 registration phase


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@...cinc.com>
> I thought I already gave my r-o-b. But anyway,
>
> Reviewed-by: Manivannan Sadhasivam <mani@...nel.org>
>
> 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.
>>

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