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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BE5B1C433EF for ; Fri, 29 Oct 2021 19:47:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9398760FC4 for ; Fri, 29 Oct 2021 19:47:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230249AbhJ2TuW (ORCPT ); Fri, 29 Oct 2021 15:50:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:34640 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229474AbhJ2TuW (ORCPT ); Fri, 29 Oct 2021 15:50:22 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id CA81860FDA; Fri, 29 Oct 2021 19:47:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1635536873; bh=/mvukm4JsopKRdXPAgr2TaSCZ5vLyw6p/53NJfMW4NI=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=sukiLpFzA5IR2OSli7ML/X5egU1HlfqVsE63oAiD9BlNBXnR3sxNmw5tF9jZWXQQ0 LY37i63+yP5vAbwqp+/Q4IxH4D5eeaLv7an2fcIKfl/cY4L4nAbCLxIsJ84PwDbQQP Cnw/N11xbWmxjm3fUpLPWNWrDIBq338uhcUxfGvE+TNSPOaHT7dQsFs55YxBLdSzE4 UdxvGu3hEjC1CNBZIZyjfi0zJUZ3O60vxxWEiWiNlHls35Iuk6SbwHJebnhJU9LwmS yemGW8wsV1OlytjkkZZiUFOh2Ieyg+sjmtFI88DQwVZg59YRy4VNSzXuEdHpEXa6Ux 6IEa5wDJpjXdw== Date: Fri, 29 Oct 2021 14:47:51 -0500 From: Bjorn Helgaas To: Sergio Paracuellos Cc: Thomas Bogendoerfer , Yanteng Si , Florian Fainelli , bcm-kernel-feedback-list@broadcom.com, Yanteng Si , Stephen Rothwell , Lorenzo Pieralisi , Rob Herring , kw@linux.com, Bjorn Helgaas , Matthias Brugger , Philipp Zabel , linux-pci , linux-arm-kernel@lists.infradead.org, "moderated list:ARM/Mediatek SoC support" , "open list:MIPS" , chenhuacai@kernel.org, sterlingteng@gmail.com, Linux Next Mailing List Subject: Re: [PATCH v2 2/3] MIPS: cm/cpc: export some missing symbols to be able to use them from driver code Message-ID: <20211029194751.GA349935@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-next@vger.kernel.org On Fri, Oct 29, 2021 at 09:37:53PM +0200, Sergio Paracuellos wrote: > On Fri, Oct 29, 2021 at 8:49 PM Bjorn Helgaas wrote: > > On Fri, Oct 29, 2021 at 07:28:47AM +0200, Sergio Paracuellos wrote: > > > On Thu, Oct 28, 2021 at 10:47 PM Bjorn Helgaas wrote: > > > > On Thu, Oct 28, 2021 at 11:59:17AM +0200, Sergio Paracuellos wrote: > > > > > On Thu, Oct 28, 2021 at 11:34 AM Sergio Paracuellos > > > > > wrote: > > > > > > On Thu, Oct 28, 2021 at 11:24 AM Thomas Bogendoerfer > > > > > > wrote: > > > > > > > On Thu, Oct 28, 2021 at 06:11:18AM +0200, Sergio Paracuellos wrote: > > > > > > > > On Thu, Oct 28, 2021 at 6:05 AM Yanteng Si wrote: > > > > > > > > > > > > > > > > > > Since commit 2bdd5238e756 ("PCI: mt7621: Add MediaTek MT7621 PCIe host controller driver") > > > > > > > > > the MT7621 PCIe host controller driver is built as a module but modpost complains once these > > > > > > > > > drivers become modules. > > > > > > > > > > > > > > > > > > ERROR: modpost: "mips_cm_unlock_other" [drivers/pci/controller/pcie-mt7621.ko] undefined! > > > > > > > > > ERROR: modpost: "mips_cpc_base" [drivers/pci/controller/pcie-mt7621.ko] undefined! > > > > > > > > > ERROR: modpost: "mips_cm_lock_other" [drivers/pci/controller/pcie-mt7621.ko] undefined! > > > > > > > > > ERROR: modpost: "mips_cm_is64" [drivers/pci/controller/pcie-mt7621.ko] undefined! > > > > > > > > > ERROR: modpost: "mips_gcr_base" [drivers/pci/controller/pcie-mt7621.ko] undefined! > > > > > > > > > > > > > > > > > > Let's just export them. > > > > > > > > > > > > > > > > > > Signed-off-by: Yanteng Si > > > > > > > > > --- > > > > > > > > > arch/mips/kernel/mips-cm.c | 5 +++++ > > > > > > > > > arch/mips/kernel/mips-cpc.c | 1 + > > > > > > > > > 2 files changed, 6 insertions(+) > > > > > > > > > > > > > > > > > > > > > > > > > Reviewed-by: Sergio Paracuellos > > > > > > > > > > > > > > could we instead make the pcie-mt761 driver non modular ? Exporting > > > > > > > all MIPS specific stuff for just making an essential driver modular > > > > > > > doesn't IMHO make much sense. > > > > > > > > > > > > The driver is modular because I have been advised other times that new > > > > > > drivers should be able to be compiled as modules and we should avoid > > > > > > using 'bool' in Kconfig for new drivers. That's the only reason. I am > > > > > > also always including as 'y' the driver since for me not having pci in > > > > > > my boards has no sense... I am ok in changing Kconfig to be 'bool' > > > > > > instead of 'tristate', but I don't know what should be the correct > > > > > > thing to do in this case. Thoughts? > > > > > > > > > > I guess we also want the driver to at least be compile tested in > > > > > 'allmodconfig' and other similars...15692a80d949 > > > > > > > > Sounds like the systems that actually use this driver require it to be > > > > built-in, and the only benefit of exporting these symbols is that we > > > > would get better compile test coverage. > > > > > > > > If that's the case, I agree that it's better to just make it > > > > non-modular. > > > > > > I agree and that was my reasoning for sending a patch to also convert > > > to bool the phy driver that this PCIe controller uses. When the pull > > > request was sent from Vinod to Greg, Greg refused to take it because > > > of that commit and the commit was reverted and a new pull request was > > > sent including this revert. This is commit 15692a80d949 ("phy: Revert > > > "phy: ralink: Kconfig: convert mt7621-pci-phy into 'bool'""). Because > > > of this I also changed the PCIe controller Kconfig from bool to > > > tristate when I sent v3 of the series which at the end were the ones > > > that was finally taken. There are also other ralink related symbols > > > that have been exported to allow to compile other drivers as a > > > modules, like the watchdog. See the commit fef532ea0cd8 ("MIPS: > > > ralink: export rt_sysc_membase for rt2880_wdt.c"). So, as I said, I > > > agree and I am using the driver as if it were a bool and also ralink > > > systems normally require all drivers built-in, but I think we have to > > > take into account also the "historical facts" here. In any case, > > > Bjorn, let me know if you want me to send whatever patch might be > > > needed. > > > > I didn't see the conversation with Greg, so I don't know the whole > > story. > > Here it is: https://www.spinics.net/lists/kernel/msg3986821.html > > > For pcie-mt7621.c, it looks like the only problem is > > setup_cm_memory_region(), which does a little coherency-related stuff. > > If we could move that to arch/mips, we could still make this tristate. > > Yes, the only mips specific function used in the driver is > 'setup_cm_memory_region()'. > > > One way might be to implement a pcibios_root_bridge_prepare() for mips > > and put the setup_cm_memory_region() stuff in there. It's not *ideal* > > because that's a strong/weak function arrangement that doesn't allow > > for multiple host bridges, but that's probably not an issue here. > > > > If we can't do that, I think making it bool is probably the right > > answer, but it would be worth a brief comment in the commit log to > > explain the issue. > > Do you mean to implement 'pcibios_root_bridge_prepare()' for MIPS > ralink? I guess this means to parse device tree and so on only to get > memory range addresses to be added to the MIPS I/O coherence regions > to make things work and then re-parse it again in the driver to do the > proper PCI setup... We end up in an arch generic driver but at the end > this controller is only present in ralink MIPS, so I am not sure that > implementing 'pcibios_root_bridge_prepare()' is worthy here... I can > explore and try to implement it if you think that it really makes > sense... but, IMHO if this is the case, just making it bool looks like > the correct thing to do. It should be trivial to put the contents of setup_cm_memory_region() into a ralink function called pcibios_root_bridge_prepare(). pcibios_root_bridge_prepare() is called with the same "struct pci_host_bridge *" argument as setup_cm_memory_region(), and it's called slightly later, so the window resources are already set up, so no DT parsing is required. It looks like a simple move and rename to me. Bjorn