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From: Paul Cercueil <paul@crapouillou.net>
To: "Maciej W. Rozycki" <macro@orcam.me.uk>,
	Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Subject: Re: [PATCH 1/2] MIPS: Allow MIPS32R2 kernel to run on P5600 and M5150
Date: Tue, 30 May 2023 11:18:56 +0300	[thread overview]
Message-ID: <45a42e25658393e3767071960214b0ff47f0737b.camel@crapouillou.net> (raw)
In-Reply-To: <alpine.DEB.2.21.2305300321520.25569@angie.orcam.me.uk>

Hi Maciej,

Le mardi 30 mai 2023 à 09:03 +0100, Maciej W. Rozycki a écrit :
> On Mon, 29 May 2023, Jiaxun Yang wrote:
> 
> > M5150 and P5600 are two MIPS32R5 kernels, however as MIPS32R5 is
> > backward compatible with MIPS32R2 there is no reason to forbid
> > M5150 and P5600 on MIPS32R2 kernel.
> 
>  What problem are you trying to solve?  The CONFIG_SYS_HAS_CPU_*
> settings 
> denote overall platform's support for the given CPU and have nothing
> to do 
> with what architecture level a given kernel has been configured for. 
> You 
> do need to get the settings right for your platform, just as you do
> in 
> 2/2, but this 1/2 part looks wrong to me.
> 
>  NB CPU_4KEC is double-listed as R1 and R2 because early revisions of
> the 
> 4KEc core were actually R1 before switching to R2, so this CPU can
> report 
> either revision.
> 
>  I don't know why CPU_XBURST is also listed as both R1 and R2, the
> history 
> looks convoluted with no explanation.  Paul, is the CPU also dual-
> revision 
> or is it just a bug and it is supposed to be listed under one ISA
> revision
> only, presumably R2?

The XBurst CPU is R1 in older Ingenic SoCs (JZ4760B and older), and R2
in newer SoCs (JZ4770 and newer).

Cheers,
-Paul

  reply	other threads:[~2023-05-30  8:19 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-29 13:52 [PATCH 1/2] MIPS: Allow MIPS32R2 kernel to run on P5600 and M5150 Jiaxun Yang
2023-05-29 13:52 ` [PATCH 2/2] MIPS: generic: Allow R5 CPUs to be selected Jiaxun Yang
2023-05-30 13:37   ` Serge Semin
2023-06-09  8:21   ` Thomas Bogendoerfer
2023-05-30  8:03 ` [PATCH 1/2] MIPS: Allow MIPS32R2 kernel to run on P5600 and M5150 Maciej W. Rozycki
2023-05-30  8:18   ` Paul Cercueil [this message]
2023-05-30  9:13     ` Maciej W. Rozycki
2023-05-30 10:11   ` Jiaxun Yang
2023-05-30 11:07     ` Maciej W. Rozycki
2023-05-30 11:54       ` Jiaxun Yang
2023-05-30 12:16         ` Maciej W. Rozycki
2023-05-30 12:41           ` Serge Semin
2023-05-30 12:51             ` Serge Semin
2023-05-30 12:57               ` Jiaxun Yang
2023-05-30 13:10           ` Jiaxun Yang
2023-05-30 13:14             ` Maciej W. Rozycki
2023-05-30 13:33             ` Serge Semin

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