Re: [Xen-devel] [PATCH v1 0/1] xen/arm: GICv2 GICH_MISR Read-Only

[Julien Grall <julien.grall@xxxxxxxxxx>]

On 10/04/15 07:21, Edgar E. Iglesias wrote:
> From: "Edgar E. Iglesias" <edgar.iglesias@xxxxxxxxxx>
> 
> Hi,

Hi Edgar,

> Does any one know why we are writing to GICH_MISR? It is a Read-Only
> register in GICv2. This showed up as illegal accesses in my QEMU logs.

I think this is a misunderstanding of the spec at the time the GIC
driver has been written. On real hardware the write access is ignored.

AFAICT, we don't even care to get a maintenance interrupt when one LR is
asserting an EOI (assuming we think this bit was enabling the assertion).

> I suspect gic-hip04 needs a similar patch. Are there any specs for
> that GIC somewhere?

This hardware is very similar to the GIC. A chinese spec has been sent
on the ML a couple of months ago [1].

Although, the HIP 04 driver is not functional anymore as the maintainers
 of this driver (from Huawei and in CC) didn't answer to previous change
to the common GIC code [2].

Regards,

[1] https://github.com/hisilicon/boards/tree/master/D01/docs

[2]
http://lists.xenproject.org/archives/html/xen-devel/2015-03/msg03835.html

-- 
Julien Grall

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