Re: [PATCH v2 3/4] arm64: dts: Add mediatek MT8173 SoC and evaluation board dts and Makefile
From: Eddie Huang <eddie.huang@mediatek.com>
Date: 2014-12-23 08:02:03
Also in:
linux-arm-kernel
Hi, On Mon, 2014-12-22 at 09:07 +0000, Marc Zyngier wrote:
On 20/12/14 20:07, Arnd Bergmann wrote:quoted
On Wednesday 17 December 2014 15:01:29 Marc Zyngier wrote:quoted
Indeed, as described in the documentation: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0471b/CHDIFAEE.html Also it is worth noticing that given how GICV is placed, it will never work with 64K pages and virtualization. Pretty sad.Does this mean no VGIC support on this platform so you have to emulate it in order to run virtual machines with 64K pages, or does it mean that it's impossible to use that way because you can't emulate it?As Peter said, this is not a configuration we're willing to support: - we don't have a API to tell userspace emulation about interrupts generated by the generic timers - we could move the whole GIC emulation into the kernel (at the moment, only the distributor is there), but that would be a complete nightmare It really looks like a case of "let's drop a bunch of 64bit cores into an existing SoC". Shame people can't read integration guidelines... M.
MT8173 use GIC-400. We check GIC-400 TRM that VGIC address is not 64KB alignment. but GIC-500 (GICv3) VGIC base address is. We also check 3.19-rc1 arm64 device tree, amd-seattle-soc.dtsi VGIC is 64KB alignment, but arm juno.dts is not, they are both GIC-400. So we are a little confused, and still try to figure out what is the correct address. Neverthless, MT8173 SoC already use 0x10224000 and 0x10225000 as VGIC base address.