Re: [PATCH] ARM64: ZynqMP: DT: Fix GIC's 'reg' property

From: SÃren Brinkmann
Date: Tue Dec 15 2015 - 04:13:35 EST


On Mon, 2015-12-14 at 05:01PM +0000, Marc Zyngier wrote:
> Mark,
>
> On 14/12/15 16:46, Mark Rutland wrote:
> > On Mon, Dec 14, 2015 at 08:31:40AM -0800, Soren Brinkmann wrote:
> >> Signed-off-by: Soren Brinkmann <soren.brinkmann@xxxxxxxxxx>
> >> ---
> >> arch/arm64/boot/dts/xilinx/zynqmp.dtsi | 6 +++---
> >> 1 file changed, 3 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/arch/arm64/boot/dts/xilinx/zynqmp.dtsi b/arch/arm64/boot/dts/xilinx/zynqmp.dtsi
> >> index 857eda5c7217..b5d1facadf16 100644
> >> --- a/arch/arm64/boot/dts/xilinx/zynqmp.dtsi
> >> +++ b/arch/arm64/boot/dts/xilinx/zynqmp.dtsi
> >> @@ -80,10 +80,10 @@
> >> gic: interrupt-controller@f9010000 {
> >> compatible = "arm,gic-400", "arm,cortex-a15-gic";
> >> #interrupt-cells = <3>;
> >> - reg = <0x0 0xf9010000 0x10000>,
> >> - <0x0 0xf902f000 0x2000>,
> >> + reg = <0x0 0xf9010000 0x1000>,
> >> + <0x0 0xf9020000 0x20000>,
> >> <0x0 0xf9040000 0x20000>,
> >> - <0x0 0xf906f000 0x2000>;
> >> + <0x0 0xf9060000 0x20000>;
> >
> > I'm confused. These sizes don't look right for GIC-400. Is this a custom
> > GIC?
>
> Probably an implementation that obey the SBSA requirement of aliasing
> the first 4kB of the CPU interface on a 64kB page, and the second one on
> the following 64kB page. See the APM system for an example of such a
> thing. I'm more concerned about the GICH region (3rd one), which has no
> reason to be bigger than 4kB.

Xilinx didn't publish the memory map yet (at least I didn't see it in the
public docs), so, let me give some excerpts:

GICD:
GICD_CTLR 0xF9010000 32 rw 0x00000000 Distributor Control Register
...
GICD_CIDR3 0xF9010FFC 32 ro 0x000000B1 Component ID3 Register

GICC:
GICC_CTLR 0xF9020000 32 rw 0x00000000 CPU Interface Control Register
...
GICC_DIR 0xF9030000 32 wo x Deactivate Interrupt Register

GICH:
GICH_HCR 0xF9040000 32 rw 0x00000000 Hypervisor Control Register
...
GICH_LR3_Alias7 0xF9050F0C 32 rw 0x00000000 List Register 3

GICV:
GICV_CTLR 0xF9060000 32 rw 0x00000000 Virtual Machine Control Register
...
GICV_DIR 0xF9070000 32 wo x VM Deactivate Interrupt Register


Regarding the GICH area, it looks like it starts at 0xF9040000 and the
alias blocks to access the other processor interfaces start at
0xF9050000.

>
> > Did this ever work wit hteh old offsets and sizes?
>
> It probably dies when trying to use EOImode==1.

Without knowing what parts we really exercise, yes, the system comes up
fine so far, but I recently found Linux boot hanging on QEMU and it
seemed to be related to time not progressing (fast enough).
I found a different DT using the values proposed here and that fixed the
hang for me.

Thanks,
SÃren
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