linux-kernel - Re: [PATCH v2 01/12] irqchip/gic: Rework gic_configure

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Date:   Mon, 19 Aug 2019 15:53:11 +0100
From:   Marc Zyngier <maz@...nel.org>
To:     Zenghui Yu <yuzenghui@...wei.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Julien Thierry <julien.thierry.kdev@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Lokesh Vutla <lokeshvutla@...com>,
        John Garry <john.garry@...wei.com>,
        linux-kernel@...r.kernel.org,
        Shameerali Kolothum Thodi 
        <shameerali.kolothum.thodi@...wei.com>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 01/12] irqchip/gic: Rework gic_configure_irq to take
 the full ICFGR base

On 19/08/2019 15:26, Zenghui Yu wrote:
> Hi Marc,
> 
> On 2019/8/6 18:01, Marc Zyngier wrote:
>> gic_configure_irq is currently passed the (re)distributor address,
>> to which it applies an a fixed offset to get to the configuration
>> registers. This offset is constant across all GICs, or rather it was
>> until to v3.1...
>>
>> An easy way out is for the individual drivers to pass the base
>> address of the configuration register for the considered interrupt.
>> At the same time, move part of the error handling back to the
>> individual drivers, as things are about to change on that front.
>>
>> Signed-off-by: Marc Zyngier <maz@...nel.org>
>> ---
>>   drivers/irqchip/irq-gic-common.c | 14 +++++---------
>>   drivers/irqchip/irq-gic-v3.c     | 11 ++++++++++-
>>   drivers/irqchip/irq-gic.c        | 10 +++++++++-
>>   drivers/irqchip/irq-hip04.c      |  7 ++++++-
>>   4 files changed, 30 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/irqchip/irq-gic-common.c b/drivers/irqchip/irq-gic-common.c
>> index b0a8215a13fc..6900b6f0921c 100644
>> --- a/drivers/irqchip/irq-gic-common.c
>> +++ b/drivers/irqchip/irq-gic-common.c
>> @@ -63,7 +63,7 @@ int gic_configure_irq(unsigned int irq, unsigned int type,
>>   	 * for "irq", depending on "type".
>>   	 */
>>   	raw_spin_lock_irqsave(&irq_controller_lock, flags);
>> -	val = oldval = readl_relaxed(base + GIC_DIST_CONFIG + confoff);
>> +	val = oldval = readl_relaxed(base + confoff);
>>   	if (type & IRQ_TYPE_LEVEL_MASK)
>>   		val &= ~confmask;
>>   	else if (type & IRQ_TYPE_EDGE_BOTH)
>> @@ -83,14 +83,10 @@ int gic_configure_irq(unsigned int irq, unsigned int type,
>>   	 * does not allow us to set the configuration or we are in a
>>   	 * non-secure mode, and hence it may not be catastrophic.
>>   	 */
>> -	writel_relaxed(val, base + GIC_DIST_CONFIG + confoff);
>> -	if (readl_relaxed(base + GIC_DIST_CONFIG + confoff) != val) {
>> -		if (WARN_ON(irq >= 32))
>> -			ret = -EINVAL;
> 
> Since this WARN_ON is dropped, the comment above should also be updated.
> But what is the reason for deleting it?  (It may give us some points
> when we fail to set type for SPIs.)

The core code already warns in the case where irq_set_type() fails, and
the duplication of warnings is pretty superfluous.

Thanks,

	M.
-- 
Jazz is not dead, it just smells funny...