From mboxrd@z Thu Jan 1 00:00:00 1970 From: santosh.shilimkar@ti.com (Santosh Shilimkar) Date: Wed, 20 Apr 2011 09:50:10 +0530 Subject: [PATCH 6/6] ARM: gic: use handle_fasteoi_irq for SPIs In-Reply-To: <1303226160.749.1.camel@e102144-lin.cambridge.arm.com> References: <1302633340-4795-1-git-send-email-will.deacon@arm.com> <1302633340-4795-7-git-send-email-will.deacon@arm.com> <4DAD6FE4.2050504@ti.com> <1303226160.749.1.camel@e102144-lin.cambridge.arm.com> Message-ID: <4DAE5EFA.7030901@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 4/19/2011 8:46 PM, Will Deacon wrote: > Hi Santosh, > > On Tue, 2011-04-19 at 12:20 +0100, Santosh Shilimkar wrote: >> On 4/13/2011 12:05 AM, Will Deacon wrote: >>> Currently, the gic uses handle_level_irq for handling SPIs (Shared >>> Peripheral Interrupts), requiring active interrupts to be masked at >>> the distributor level during IRQ handling. >>> >>> On a virtualised system, only the CPU interfaces are virtualised in >>> hardware. Accesses to the distributor must be trapped by the >>> hypervisor, adding latency to the critical interrupt path in Linux. >>> >>> This patch modifies the GIC code to use handle_fasteoi_irq for handling >>> interrupts, which only requires us to signal EOI to the CPU interface >>> when handling is complete. Cascaded IRQ handling is also updated to use >>> the chained IRQ enter/exit functions to honour the flow control of the >>> parent chip. >>> >>> Note that commit 846afbd1 ("GIC: Dont disable INT in ack callback") >>> broke cascading interrupts by forgetting to add IRQ masking. This is >>> no longer an issue because the unmask call is now unnecessary. >>> >>> Tested on Versatile Express and Realview EB (1176 w/ cascaded GICs). >>> >>> Cc: Abhijeet Dharmapurikar >>> Cc: Russell King - ARM Linux >>> Acked-by: Catalin Marinas >>> Signed-off-by: Will Deacon >>> --- >> Tested with OMAP4. >> Acked-by: Santosh Shilimkar >> Tested-by: Santosh Shilimkar > > Cheers for this. I'll add this and the tags for the OMAP-specific patch > (for some reason you dropped the list when you replied with your Ack). > Sure. By mistake I did reply instead of reply all :( Regards Santosh