From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C7D89C433EF for ; Fri, 20 May 2022 10:44:53 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4L4Ndw2NVKz3cdV for ; Fri, 20 May 2022 20:44:52 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=heyquark.com (client-ip=2001:4b98:dc4:8::224; helo=relay4-d.mail.gandi.net; envelope-from=ash@heyquark.com; receiver=) X-Greylist: delayed 25376 seconds by postgrey-1.36 at boromir; Fri, 20 May 2022 20:44:26 AEST Received: from relay4-d.mail.gandi.net (relay4-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::224]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4L4NdQ0bmZz3bjq for ; Fri, 20 May 2022 20:44:24 +1000 (AEST) Received: (Authenticated sender: ash@heyquark.com) by mail.gandi.net (Postfix) with ESMTPSA id 04FB3E000B; Fri, 20 May 2022 10:44:08 +0000 (UTC) Message-ID: <935b426a-6c64-beb0-907f-8c3f0a089ab7@heyquark.com> Date: Fri, 20 May 2022 20:44:04 +1000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH 11/12] powerpc: wiiu: don't enforce flat memory Content-Language: en-US To: =?UTF-8?Q?Pali_Roh=c3=a1r?= References: <20220302044406.63401-1-ash@heyquark.com> <20220302044406.63401-12-ash@heyquark.com> <20220513224353.n56qg5fhstbaqhfz@pali> <20220520080454.c3cqodsdbfbkmg56@pali> From: Ash Logan In-Reply-To: <20220520080454.c3cqodsdbfbkmg56@pali> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org, robh+dt@kernel.org, paulus@samba.org, linuxppc-dev@lists.ozlabs.org, j.ne@posteo.net Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 20/5/22 18:04, Pali Rohár wrote: > On Friday 20 May 2022 13:41:04 Ash Logan wrote: >> On 14/5/22 08:43, Pali Rohár wrote: >>> On Wednesday 02 March 2022 15:44:05 Ash Logan wrote: >>>> pgtable_32.c:mapin_ram loops over each valid memory range, which means >>>> non-contiguous memory just works. >>> >>> Hello! Does it mean that non-contiguous memory works for any 32-bit >>> powerpc platform, and not only for wiiu? If yes, should not be >>> non-contiguous memory support enabled for all 32-bit ppc boards then? >> >> Hi! Sorry for my delayed response. As best I can tell, it does indeed >> Just Work, but I have only been able to test on wiiu which is missing a >> lot of features other boards have (like PCI) - so it's possible there's >> still an assumption elsewhere in the kernel that I haven't hit. >> >> As best I can tell, the Wii and Wii U are the only 32-bit powerpc boards >> out there where it's even possible to have non-contiguous memory. > > What is the reason that those two boards are the **only**? Is there some > specific requirement from bootloader or hardware to "enable" > non-contiguous memory support? Not that I know of, I was just saying that I was only aware of those two boards where the memory map isn't contiguous, and that is the only place where it has been tested. Evidently you know of another board! > I'm interested in enabling non-contiguous memory support for P2020-based > board as it has gaps in its 32-bit memory layout and which could be used > for RAM mapping when 4GB DDR3 module is plugged in (default is 2GB). If it's like the Wii or Wii U (some memory at 0, a gap for MMIO or whatever, then more memory at a higher address) then you should try a patch along these lines, because barring the unknowns I mentioned before it should work. At least as far as I'm aware ;) >>>> Signed-off-by: Ash Logan >>>> --- >>>> arch/powerpc/mm/init_32.c | 4 ++-- >>>> 1 file changed, 2 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c >>>> index 3d690be48e84..59a84629d9a0 100644 >>>> --- a/arch/powerpc/mm/init_32.c >>>> +++ b/arch/powerpc/mm/init_32.c >>>> @@ -125,10 +125,10 @@ void __init MMU_init(void) >>>> * lowmem_end_addr is initialized below. >>>> */ >>>> if (memblock.memory.cnt > 1) { >>>> -#ifndef CONFIG_WII >>>> +#if !defined(CONFIG_WII) && !defined(CONFIG_WIIU) >>>> memblock_enforce_memory_limit(memblock.memory.regions[0].size); >>>> pr_warn("Only using first contiguous memory region\n"); >>>> -#else >>>> +#elif defined(CONFIG_WII) >>>> wii_memory_fixups(); >>>> #endif >>>> } >>>> -- >>>> 2.35.1 >>>>