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Re: [Qemu-devel] Subject: [PATCH] target-ppc: Add global timer group A t
From: |
alarson |
Subject: |
Re: [Qemu-devel] Subject: [PATCH] target-ppc: Add global timer group A to open-pic. |
Date: |
Sun, 23 Apr 2017 19:37:55 -0500 |
David Gibson <address@hidden> wrote on 04/23/2017 06:17:22
PM:
> From: David Gibson <address@hidden>
> To: Aaron Larson <address@hidden>
> Cc: address@hidden, address@hidden, address@hidden
> Date: 04/23/2017 06:54 PM
> Subject: Re: Subject: [PATCH] target-ppc: Add global timer group A to
open-pic.
>
> On Fri, Apr 21, 2017 at 02:58:23PM -0700, Aaron Larson wrote:
> > Add global timer group A to open-pic. This patch is still somewhat
> > dubious because I'm not sure how to determine what QEMU wants for the
> > timer frequency. Suggestions solicited.
>
> This commit message really needs some more context. What's a "global
> time group A" a and why do we want it?
The open-pic spec includes two sets/groups of timers, groups A and B,
4 timers in each group. Previously in QEMU the timer group A
registers were implemented but they did not "count" or generate any
interrupts. The patch makes the timers to do both (count and generate
interrupts).
About a year ago I mentioned that we had implemented this and offered
to submit a patch, which seemed to be acceptable. Sadly, when I
reviewed the implementation it had several egregious errors that I
didn't know how to fix until recently.
Quite frankly I didn't expect the patch to be accepted in its current
form for the reason mentioned in the above commit log and was hoping
for some guidance. If this is no longer a desirable patch, I can
certainly continue to maintain it locally for our use.\
Aaron.