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From: Valentin Schneider <valentin.schneider@arm.com>
To: Ruifeng Zhang <ruifeng.zhang0110@gmail.com>,
	linux@armlinux.org.uk, sudeep.holla@arm.com,
	gregkh@linuxfoundation.org, rafael@kernel.org,
	a.p.zijlstra@chello.nl, dietmar.eggemann@arm.com,
	mingo@kernel.org, ruifeng.zhang1@unisoc.com,
	nianfu.bai@unisoc.com
Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/1] arm: topology: parse the topology from the dt
Date: Mon, 12 Apr 2021 12:31:59 +0100	[thread overview]
Message-ID: <87y2dnn3gw.mognet@arm.com> (raw)
In-Reply-To: <20210412070819.23493-1-ruifeng.zhang0110@gmail.com>


Hi,

On 12/04/21 15:08, Ruifeng Zhang wrote:
> From: Ruifeng Zhang <ruifeng.zhang1@unisoc.com>
>
> The arm topology still parse from the MPIDR, but it is incomplete.  When
> the armv8.3 cpu runs in aarch32 mode, it will parse out the wrong topology.
>
> armv7 (A7) mpidr is:
> [11:8]      [7:2]       [1:0]
> cluster     reserved    cpu
>
> armv8.3 (A55) mpidr is:
> [23:16]     [15:8]      [7:0]
> cluster     cpu         thread
>
> For compatibility to keep the function of get capacity from default
> cputype, renamed arm parse_dt_topology to get_cputype_capacity and delete
> related logic of parse from dt.
> Arm using the same parse_dt_topology function as arm64.
>
> The arm device boot step is to look for the default cputype and get cpu
> capacity firstly. Then parse the topology and capacity from dt to replace
> default values.
>

I'm afraid I don't get it.

CONFIG_COMPAT lets you run 32-bit stuff at EL0, but the kernel is still
arm64. So if you take your armv8.3 system, the topology parsed by the
kernel will be the same regardless of CONFIG_COMPAT.

Could you elaborate on what problem you are trying to fix here?

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  reply	other threads:[~2021-04-12 11:33 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-12  7:08 [PATCH 1/1] arm: topology: parse the topology from the dt Ruifeng Zhang
2021-04-12 11:31 ` Valentin Schneider [this message]
2021-04-12 12:20   ` Ruifeng Zhang
2021-04-12 12:40     ` Dietmar Eggemann
2021-04-13  6:18       ` Ruifeng Zhang
2021-04-12 15:32     ` Valentin Schneider
2021-04-13  6:13       ` Ruifeng Zhang
2021-04-13 11:40         ` Valentin Schneider
2021-04-13 13:26           ` Ruifeng Zhang
2021-04-14  9:42             ` Dietmar Eggemann
2021-04-14 11:26               ` Ruifeng Zhang
2021-04-14 13:53                 ` Dietmar Eggemann

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