From: "Jonathan Neuschäfer" <j.neuschaefer@gmx.net>
To: Christophe LEROY <christophe.leroy@c-s.fr>
Cc: "Jonathan Neuschäfer" <j.neuschaefer@gmx.net>,
linuxppc-dev@lists.ozlabs.org, "Joel Stanley" <joel@jms.id.au>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 0/6] DISCONTIGMEM support for PPC32
Date: Wed, 21 Feb 2018 15:42:40 +0100 [thread overview]
Message-ID: <20180221144240.pfu2run3pixt3pzo@latitude> (raw)
In-Reply-To: <193a407d-e6b8-9e29-af47-3d401b6414a0@c-s.fr>
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Hi,
On Wed, Feb 21, 2018 at 08:06:10AM +0100, Christophe LEROY wrote:
>
>
> Le 20/02/2018 à 17:14, Jonathan Neuschäfer a écrit :
> > This patchset adds support for DISCONTIGMEM on 32-bit PowerPC. This is
> > required to properly support the Nintendo Wii's memory layout, in which
> > there are two blocks of RAM and MMIO in the middle.
> >
> > Previously, this memory layout was handled by code that joins the two
> > RAM blocks into one, reserves the MMIO hole, and permits allocations of
> > reserved memory in ioremap. This hack didn't work with resource-based
> > allocation (as used for example in the GPIO driver for Wii[1]), however.
> >
> > After this patchset, users of the Wii can either select CONFIG_FLATMEM
> > to get the old behaviour, or CONFIG_DISCONTIGMEM to get the new
> > behaviour.
>
> My question might me stupid, as I don't know PCC64 in deep, but when looking
> at page_is_ram() in arch/powerpc/mm/mem.c, I have the feeling the PPC64
> implements ram by blocks. Isn't it what you are trying to achieve ? Wouldn't
> it be feasible to map to what's done in PPC64 for PPC32 ?
Using page_is_ram in __ioremap_caller and the same memblock-based
approach that's used on PPC64 on PPC32 *should* work, but I think due to
the following line in initmem_init, it won't:
memblock_set_node(0, (phys_addr_t)ULLONG_MAX, &memblock.memory, 0);
Thanks,
Jonathan Neuschäfer
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next prev parent reply other threads:[~2018-02-21 14:42 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-20 16:14 [PATCH 0/6] DISCONTIGMEM support for PPC32 Jonathan Neuschäfer
2018-02-20 16:14 ` [PATCH 1/6] powerpc/mm/32: Use pfn_valid to check if pointer is in RAM Jonathan Neuschäfer
2018-02-20 17:45 ` christophe leroy
2018-02-21 13:51 ` Jonathan Neuschäfer
2018-02-21 14:44 ` Jonathan Neuschäfer
2018-02-20 16:14 ` [PATCH 2/6] powerpc: numa: Fix overshift on PPC32 Jonathan Neuschäfer
2018-02-20 16:14 ` [PATCH 3/6] powerpc: numa: Use the right #ifdef guards around functions Jonathan Neuschäfer
2018-02-20 16:14 ` [PATCH 4/6] powerpc: numa: Restrict fake NUMA enulation to CONFIG_NUMA systems Jonathan Neuschäfer
2018-02-20 16:14 ` [PATCH 5/6] powerpc: Implement DISCONTIGMEM and allow selection on PPC32 Jonathan Neuschäfer
2018-02-20 23:46 ` kbuild test robot
2018-02-21 16:08 ` Jonathan Neuschäfer
2018-02-21 17:53 ` christophe leroy
2018-02-20 16:14 ` [PATCH 6/6] powerpc: wii: Don't rely on reserved memory hack if DISCONTIGMEM is set Jonathan Neuschäfer
2018-02-21 7:06 ` [PATCH 0/6] DISCONTIGMEM support for PPC32 Christophe LEROY
2018-02-21 14:42 ` Jonathan Neuschäfer [this message]
2018-02-21 15:02 ` Christophe LEROY
2018-02-21 16:52 ` Jonathan Neuschäfer
2018-02-21 23:31 ` Jonathan Neuschäfer
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