linux-kernel - Re: [PATCH 2/2] irqchip/gic: Ensure gic_cpu_if

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Message-ID: <55BB2990.20203@nvidia.com>
Date:	Fri, 31 Jul 2015 08:53:52 +0100
From:	Jon Hunter <jonathanh@...dia.com>
To:	Marc Zyngier <marc.zyngier@....com>,
	Russell King <linux@....linux.org.uk>,
	"nicolas.pitre@...aro.org" <nicolas.pitre@...aro.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	"Jason Cooper" <jason@...edaemon.net>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 2/2] irqchip/gic: Ensure gic_cpu_if_up/down() programs
 correct GIC instance


On 30/07/15 19:11, Marc Zyngier wrote:
> On 30/07/15 18:56, Jon Hunter wrote:
>>
>> On 30/07/15 17:51, Marc Zyngier wrote:
>>> On 30/07/15 17:26, Jon Hunter wrote:
>>>> Commit 3228950621d9 ("irqchip: gic: Preserve gic V2 bypass bits in cpu
>>>> ctrl register") added a new function, gic_cpu_if_up(), to program the
>>>> GIC CPU_CTRL register. This function assumes that there is only one GIC
>>>> instance present and hence always uses the chip data for the primary GIC
>>>> controller. Although it is not common for there to be a secondary, some
>>>> devices do support a secondary. Therefore, fix this by passing
>>>> gic_cpu_if_up() a pointer to the appropriate chip data structure.
>>>>
>>>> Similarly, the function gic_cpu_if_down() only assumes that there is a
>>>> single GIC instance present. Update this function so that an instance
>>>> number is passed for the appropriate GIC. The vexpress TC2 (which has
>>>> a single GIC) is currently the only user of this function and so update
>>>> it accordingly.
>>>>
>>>> Signed-off-by: Jon Hunter <jonathanh@...dia.com>
>>>> ---
>>>> I was hoping to make the gic_cpu_if_up/down function more symmetric as we
>>>> discussed but it is not possible to pass the gic_nr to gic_cpu_if_up()
>>>> from all the places called without making more changes. However, given
>>>> that gic_cpu_if_up() is a local function and gic_cpu_if_down() is public,
>>>> may be it does not matter too much.
>>>>
>>>>  arch/arm/mach-vexpress/tc2_pm.c |  2 +-
>>>>  drivers/irqchip/irq-gic.c       | 14 +++++++-------
>>>>  include/linux/irqchip/arm-gic.h |  2 +-
>>>>  3 files changed, 9 insertions(+), 9 deletions(-)
>>>>
>>>> diff --git a/arch/arm/mach-vexpress/tc2_pm.c b/arch/arm/mach-vexpress/tc2_pm.c
>>>> index b3328cd46c33..1aa4ccece69f 100644
>>>> --- a/arch/arm/mach-vexpress/tc2_pm.c
>>>> +++ b/arch/arm/mach-vexpress/tc2_pm.c
>>>> @@ -80,7 +80,7 @@ static void tc2_pm_cpu_powerdown_prepare(unsigned int cpu, unsigned int cluster)
>>>>  	 * to the CPU by disabling the GIC CPU IF to prevent wfi
>>>>  	 * from completing execution behind power controller back
>>>>  	 */
>>>> -	gic_cpu_if_down();
>>>> +	gic_cpu_if_down(0);
>>>>  }
>>>>  
>>>>  static void tc2_pm_cluster_powerdown_prepare(unsigned int cluster)
>>>> diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
>>>> index 7566fe259d27..cf9aca22120f 100644
>>>> --- a/drivers/irqchip/irq-gic.c
>>>> +++ b/drivers/irqchip/irq-gic.c
>>>> @@ -356,10 +356,10 @@ static u8 gic_get_cpumask(struct gic_chip_data *gic)
>>>>  	return mask;
>>>>  }
>>>>  
>>>> -static void gic_cpu_if_up(void)
>>>> +static void gic_cpu_if_up(struct gic_chip_data *gic)
>>>>  {
>>>> -	void __iomem *cpu_base = gic_data_cpu_base(&gic_data[0]);
>>>> -	void __iomem *dist_base = gic_data_dist_base(&gic_data[0]);
>>>> +	void __iomem *cpu_base = gic_data_cpu_base(gic);
>>>> +	void __iomem *dist_base = gic_data_dist_base(gic);
>>>
>>> Which tree is that against? I don't have a dist_base in mainline...
>>
>> It is based upon linux-next. I can rebase on the current mainline if you
>> want them for v4.2.
> 
> It'd be good to fix it in mainline ASAP, as the Realview platforms are a
> tiny bit dead at the moment, so a 4.2-rc would be good. The conflict
> with Russell's FIQ work won't be hard to solve anyway.

Ok, will rebase on 4.2-rc4. I will also fix-up my incompetence, I just
pointed out in the above.

Jon
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