From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc.zyngier@arm.com (Marc Zyngier) Date: Wed, 10 Feb 2016 10:16:31 +0000 Subject: [PATCH V3 03/10] irqchip,GICv3,ACPI: Add redistributor support via GICC structures. In-Reply-To: <1453209083-3358-4-git-send-email-tn@semihalf.com> References: <1453209083-3358-1-git-send-email-tn@semihalf.com> <1453209083-3358-4-git-send-email-tn@semihalf.com> Message-ID: <56BB0DFF.1040802@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 19/01/16 13:11, Tomasz Nowicki wrote: > Following ACPI spec: > On systems supporting GICv3 and above, GICR Base Address in MADT GICC > structure holds the 64-bit physical address of the associated Redistributor. > If all of the GIC Redistributors are in the always-on power domain, > GICR structures should be used to describe the Redistributors instead, > and this field must be set to 0. > > It means that we have two ways to initialize registirbutors map. > 1. via GICD structure which can accommodate many redistributors as a region > 2. via GICC which is able to describe single redistributor > > This patch is going to add support for second option. > Considering redistributors, GICD and GICC subtables have be mutually > exclusive. While discovering and mapping redistributor, we need to know > its size in advance. For the GICC case, redistributor can be in > a power-domain that is off, thus we cannot relay on GICR TYPER register. > Therefore, we get GIC version from distributor register and map 2xSZ_64K > for GICv3 and 4xSZ_64K for GICv4. > > Signed-off-by: Hanjun Guo > Signed-off-by: Tomasz Nowicki This is incredibly convoluted, but I'm not sure there is a better way given the current ACPI API. Still, it hurts. Acked-by: Marc Zyngier M. -- Jazz is not dead. It just smells funny...