linux-kernel - Re: [PATCH 2/7] genirq/msi: Limit level-triggered MSI to platform devices

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Message-ID: <7528a81e-f391-3bae-7ad0-6132f44d5a70@arm.com>
Date:   Tue, 1 May 2018 11:15:03 +0100
From:   Marc Zyngier <marc.zyngier@....com>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     Jason Cooper <jason@...edaemon.net>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/7] genirq/msi: Limit level-triggered MSI to platform
 devices

On 26/04/18 20:50, Thomas Gleixner wrote:
> On Mon, 23 Apr 2018, Marc Zyngier wrote:
> 
>> Nobody would be insane enough to try and use level triggered
>> MSIs on PCI, but let's make sure it doesn't happen. Also,
>> let's mandate that the irqchip backing the platform MSI domain
>> is providing an irq_set_type method (or the whole thing would
>> be a bit useless).
>>
>> Signed-off-by: Marc Zyngier <marc.zyngier@....com>
>> ---
>>  drivers/base/platform-msi.c | 3 +++
>>  drivers/pci/msi.c           | 3 +++
>>  2 files changed, 6 insertions(+)
>>
>> diff --git a/drivers/base/platform-msi.c b/drivers/base/platform-msi.c
>> index 8e22073aeeed..3b9694a6beaa 100644
>> --- a/drivers/base/platform-msi.c
>> +++ b/drivers/base/platform-msi.c
>> @@ -101,6 +101,9 @@ static void platform_msi_update_chip_ops(struct msi_domain_info *info)
>>  		chip->irq_set_affinity = msi_domain_set_affinity;
>>  	if (!chip->irq_write_msi_msg)
>>  		chip->irq_write_msi_msg = platform_msi_write_msg;
>> +	if (WARN_ON((info->flags & MSI_FLAG_LEVEL_CAPABLE) &&
>> +		    !chip->irq_set_type))
> 
> Shouldn't we just require something like IRQCHIP_SUPPORTS_MSI_LEVEL or such
> in chip->flags being set instead?
That definitely makes sense. Thanks for the suggestion.

	M.
-- 
Jazz is not dead. It just smells funny...