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From: "Yun Wu (Abel)" <wuyun.wu@huawei.com>
To: Marc Zyngier <marc.zyngier@arm.com>
Cc: "tglx@linutronix.de" <tglx@linutronix.de>,
	"jason@lakedaemon.net" <jason@lakedaemon.net>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 3/5] irqchip: gicv3-its: use 64KB page as default granule
Date: Sat, 31 Jan 2015 09:33:57 +0800	[thread overview]
Message-ID: <54CC3105.1050200@huawei.com> (raw)
In-Reply-To: <54CBD8FD.1030908@arm.com>

On 2015/1/31 3:18, Marc Zyngier wrote:

> On 30/01/15 07:46, Yun Wu wrote:
>> The field of page size in register GITS_BASERn might be read-only
>> if an implementation only supports a single, fixed page size. But
>> currently the ITS driver will throw out an error when PAGE_SIZE
>> is less than the minimum size supported by an ITS. So addressing
>> this problem by using 64KB pages as default granule for all the
>> ITS base tables.
> 
> Do you actually know of an implementation with such a behaviour?

Yes, Hisilicon implemented a fixed page size of 16KB.

> 
>> Signed-off-by: Yun Wu <wuyun.wu@huawei.com>
>> ---
>>  drivers/irqchip/irq-gic-v3-its.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
>> index 2a08d85..430bc92 100644
>> --- a/drivers/irqchip/irq-gic-v3-its.c
>> +++ b/drivers/irqchip/irq-gic-v3-its.c
>> @@ -801,7 +801,7 @@ static int its_alloc_tables(struct its_node *its)
>>  	int err;
>>  	int i;
>>  	int size;
>> -	int psz = PAGE_SIZE;
>> +	int psz = SZ_64K;
>>  	u64 shr = GITS_BASER_InnerShareable;
>>
>>  	for (i = 0; i < GITS_BASER_NR_REGS; i++) {
> 
> Assuming such an implementation exists, you'll have to rebase this on
> top of the patch I mentioned in my reply to patch #1.
> 

OK, I will.

Thanks,
	Abel


WARNING: multiple messages have this Message-ID (diff)
From: wuyun.wu@huawei.com (Yun Wu (Abel))
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 3/5] irqchip: gicv3-its: use 64KB page as default granule
Date: Sat, 31 Jan 2015 09:33:57 +0800	[thread overview]
Message-ID: <54CC3105.1050200@huawei.com> (raw)
In-Reply-To: <54CBD8FD.1030908@arm.com>

On 2015/1/31 3:18, Marc Zyngier wrote:

> On 30/01/15 07:46, Yun Wu wrote:
>> The field of page size in register GITS_BASERn might be read-only
>> if an implementation only supports a single, fixed page size. But
>> currently the ITS driver will throw out an error when PAGE_SIZE
>> is less than the minimum size supported by an ITS. So addressing
>> this problem by using 64KB pages as default granule for all the
>> ITS base tables.
> 
> Do you actually know of an implementation with such a behaviour?

Yes, Hisilicon implemented a fixed page size of 16KB.

> 
>> Signed-off-by: Yun Wu <wuyun.wu@huawei.com>
>> ---
>>  drivers/irqchip/irq-gic-v3-its.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
>> index 2a08d85..430bc92 100644
>> --- a/drivers/irqchip/irq-gic-v3-its.c
>> +++ b/drivers/irqchip/irq-gic-v3-its.c
>> @@ -801,7 +801,7 @@ static int its_alloc_tables(struct its_node *its)
>>  	int err;
>>  	int i;
>>  	int size;
>> -	int psz = PAGE_SIZE;
>> +	int psz = SZ_64K;
>>  	u64 shr = GITS_BASER_InnerShareable;
>>
>>  	for (i = 0; i < GITS_BASER_NR_REGS; i++) {
> 
> Assuming such an implementation exists, you'll have to rebase this on
> top of the patch I mentioned in my reply to patch #1.
> 

OK, I will.

Thanks,
	Abel

  reply	other threads:[~2015-01-31  1:34 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-30  7:46 [PATCH 0/5] enhance configuring an ITS Yun Wu
2015-01-30  7:46 ` Yun Wu
2015-01-30  7:46 ` [PATCH 1/5] irqchip: gicv3-its: allocate proper size for DT Yun Wu
2015-01-30  7:46   ` Yun Wu
2015-01-30 19:10   ` Marc Zyngier
2015-01-30 19:10     ` Marc Zyngier
2015-01-31  1:57     ` Yun Wu (Abel)
2015-01-31  1:57       ` Yun Wu (Abel)
2015-01-30  7:46 ` [PATCH 2/5] irqchip: gicv3-its: zero itt before handling to hardware Yun Wu
2015-01-30  7:46   ` Yun Wu
2015-01-30 19:24   ` Marc Zyngier
2015-01-30 19:24     ` Marc Zyngier
2015-01-30  7:46 ` [PATCH 3/5] irqchip: gicv3-its: use 64KB page as default granule Yun Wu
2015-01-30  7:46   ` Yun Wu
2015-01-30 19:18   ` Marc Zyngier
2015-01-30 19:18     ` Marc Zyngier
2015-01-31  1:33     ` Yun Wu (Abel) [this message]
2015-01-31  1:33       ` Yun Wu (Abel)
2015-01-30  7:46 ` [PATCH 4/5] irqchip: gicv3-its: define macros for GITS_CTLR fields Yun Wu
2015-01-30  7:46   ` Yun Wu
2015-01-30  7:46 ` [PATCH 5/5] irqchip: gicv3-its: add support for power down Yun Wu
2015-01-30  7:46   ` Yun Wu
2015-01-30 19:23   ` Marc Zyngier
2015-01-30 19:23     ` Marc Zyngier
2015-01-31  1:43     ` Yun Wu (Abel)
2015-01-31  1:43       ` Yun Wu (Abel)

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