From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f66.google.com (mail-ej1-f66.google.com [209.85.218.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 42B4C1F3D4B for ; Tue, 21 Jan 2025 14:37:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.66 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737470273; cv=none; b=XAv3/yMhzMBKFvxXpd6YeUB3aF3VKUiHpcitNr4XeowJuur2pWzt0855JOP7K7/C+RtRyV1NPTfchVMhCbGZ+XesByoGBrCJFvn5i5UjIavwa8DsnuveUAChC2ZKJbnKkiMtIX3zGYFyV6ZsAmmwCPf9xdLEBsinqD4JLHwZEyo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737470273; c=relaxed/simple; bh=dSRv4Z+gtUFCtc/LYOBMFVK+8Os64RgJXKR8uIWokc8=; h=From:Date:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=R1cnc6snRV3aE2UoMPmCGxNqRlYRNLIvAoB1nLTOYteTCv15dIfG1v/s+yrZL6T3OBgc92Eqo4h5Txh7JghBqPf2ecS341cXbTSJ6hAT7bIR7kRf1Y58l0gBjMB+w4UG4MRTvStNhC8QmXiCCY5s5cWUW6INuqpMtg2Y/dJfAso= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b=V7Jh7V3C; arc=none smtp.client-ip=209.85.218.66 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b="V7Jh7V3C" Received: by mail-ej1-f66.google.com with SMTP id a640c23a62f3a-aaef00ab172so868577166b.3 for ; Tue, 21 Jan 2025 06:37:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1737470269; x=1738075069; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:from:to:cc:subject:date:message-id:reply-to; bh=OP+yLZsGZnxZl3XcQ+L57qZeoo+bUmeJesOySRXDb2M=; b=V7Jh7V3CnncDJtbb8BG8tMUpk7GbX2Mhe20YwMr1qfCPFx6/n22zmyEIHvET25lmk7 BOZ6oSV1el/JTWGFIx1SScJNEgAB4vo/kZaYVlKJDY/VCYj+vwdwJjKDU53kwpjoIemN TZoy6ZwsWi7B7N6jzZV4JZhhuzD3Ko3DlyrWsrqd9nw7iLYDxtr+1/qk8V8ookkYqQLf E9TnLsbRqfwWMElnqhy+pEje8fN7HuzSY1PhvKkK3GVK3E8EMY3dxhP3ugGYRgVmrzpJ Twf7FUqZTf1j4vAdHg6h1BTKAcomstHvuf1vPvCsEbyCtViG7sbvdSn+e8JXVxi7Pe3Q ldGw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1737470269; x=1738075069; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=OP+yLZsGZnxZl3XcQ+L57qZeoo+bUmeJesOySRXDb2M=; b=nP7cwbFJ2ZCdbz60Uf1WcwYfuoSd82lODTe6iw28raOMoeeV360GnEfT0XRIBFtVdP EgRYXdO+7RceXP7o0sgBf49uFdLmadsf2JrOqz4OFisbTpGu5sWAXLQ5HI3ezyDrlotM DCrXpXSnlzbNFKsNwiTFqK89kYfHYqBZ+M1wT1hWpAlCFiJDa288peG6/2TbBJ2vZvug ftUWqSeNBumIwXvNZ6UYcWnwM9B9xkS9S9DDPii9kWuis/kB8hqpbLzVjVrinQQS7T0C FokpWg43G0Bq/DUs/8xRCwgLlTfyTSc2XvnYMWgIv7NV7Wi1GGFQbBYnTzFnHQt5tW7p gZ7g== X-Forwarded-Encrypted: i=1; AJvYcCVuqLaEFZGXVVSc1Lpdtk2m0egT6+EaFNU/SCsYIzfM9xu0zEOlb3RIbFXoSvrM3ApKE5CTf8NeW0B2@vger.kernel.org X-Gm-Message-State: AOJu0YzBdwZT44pCNpztX3J4IMRhp6hzGKqPPokyjw3JfdfzJLIRnjCV kaJLVzCdHiZcsgJcrV2i4pzOIyhjMTB1SwfejC4bYFMjiTJ9/WIx4ZAyYGU8zD8= X-Gm-Gg: ASbGncv1o0+FKvKH/V+QlaUghxiNoFKSznP+Rxe+Pk8+xEC0fiRJrbSG/5Tqmh+ic9V EiaiVrF3GgeC9pUx2Mfr1b9jqbj3k0vRdOq5EaaHlILsbBy7atI4KsuITemVsQLJNkJCCKCuoxZ v+F8ol9lwa7/B1SChLqlAmGiVdmDNlVxgKnfSew4H1XP1CZqDa1gqhafcyb0WLjZtslFQvPTkID ghZn1Hdv3i8PZVo9Mu746H+vIpABCVU+e7cFgBrhZPZOC2/4Q1JezoHHbAnKwtdz5QGFOYUGgDK 8LwzC+jTd7GIQyfnMvgQSVzleNx4yC9ZG45O2W8p X-Google-Smtp-Source: AGHT+IHrdKVrwSeMZy2lajXUFaaswl4BBAIMKjnMweMj9CE4d/aKkVXO5Bbtz0sEBeHig2196Qh7kg== X-Received: by 2002:a05:6402:5106:b0:5d0:ced8:d22d with SMTP id 4fb4d7f45d1cf-5db7db07334mr41029714a12.22.1737470269436; Tue, 21 Jan 2025 06:37:49 -0800 (PST) Received: from localhost (host-87-14-236-197.retail.telecomitalia.it. [87.14.236.197]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-ab64998511esm53461766b.68.2025.01.21.06.37.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Jan 2025 06:37:49 -0800 (PST) From: Andrea della Porta X-Google-Original-From: Andrea della Porta Date: Tue, 21 Jan 2025 15:38:42 +0100 To: Greg Kroah-Hartman Cc: Andrea della Porta , Michael Turquette , Stephen Boyd , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Florian Fainelli , Broadcom internal kernel review list , Lorenzo Pieralisi , Krzysztof Wilczynski , Manivannan Sadhasivam , Bjorn Helgaas , Linus Walleij , Catalin Marinas , Will Deacon , Bartosz Golaszewski , Derek Kiernan , Dragan Cvetic , Arnd Bergmann , Saravana Kannan , linux-clk@vger.kernel.org, devicetree@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-gpio@vger.kernel.org, Masahiro Yamada , Stefan Wahren , Herve Codina , Luca Ceresoli , Thomas Petazzoni , Andrew Lunn Subject: Re: [PATCH v6 08/10] misc: rp1: RaspberryPi RP1 misc driver Message-ID: References: <550590a5a0b80dd8a0c655921ec0aa41a67c8148.1736776658.git.andrea.porta@suse.com> <2025011722-motocross-finally-e664@gregkh> <2025012143-rippling-rehydrate-581b@gregkh> <2025012157-bonsai-caddie-19b2@gregkh> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2025012157-bonsai-caddie-19b2@gregkh> Hi Greg, On 15:18 Tue 21 Jan , Greg Kroah-Hartman wrote: > On Tue, Jan 21, 2025 at 02:59:21PM +0100, Andrea della Porta wrote: > > Hi Greg, > > > > On 09:48 Tue 21 Jan , Greg Kroah-Hartman wrote: > > > On Tue, Jan 21, 2025 at 09:43:37AM +0100, Andrea della Porta wrote: > > > > Hi Greg, > > > > > > > > On 12:47 Fri 17 Jan , Greg Kroah-Hartman wrote: > > > > > On Mon, Jan 13, 2025 at 03:58:07PM +0100, Andrea della Porta wrote: > > > > > > The RaspberryPi RP1 is a PCI multi function device containing > > > > > > peripherals ranging from Ethernet to USB controller, I2C, SPI > > > > > > and others. > > > > > > > > > > > > Implement a bare minimum driver to operate the RP1, leveraging > > > > > > actual OF based driver implementations for the on-board peripherals > > > > > > by loading a devicetree overlay during driver probe. > > > > > > > > > > > > The peripherals are accessed by mapping MMIO registers starting > > > > > > from PCI BAR1 region. > > > > > > > > > > > > With the overlay approach we can achieve more generic and agnostic > > > > > > approach to managing this chipset, being that it is a PCI endpoint > > > > > > and could possibly be reused in other hw implementations. The > > > > > > presented approach is also used by Bootlin's Microchip LAN966x > > > > > > patchset (see link) as well, for a similar chipset. > > > > > > > > > > > > For reasons why this driver is contained in drivers/misc, please > > > > > > check the links. > > > > > > > > > > Links aren't always around all the time, please document it here why > > > > > this is needed, and then links can "add to" that summary. > > > > > > > > Ack. > > > > > > > > > > > > > > > This driver is heavily based on downstream code from RaspberryPi > > > > > > Foundation, and the original author is Phil Elwell. > > > > > > > > > > > > Link: https://datasheets.raspberrypi.com/rp1/rp1-peripherals.pdf > > > > > > > > ... > > > > > > > > > > diff --git a/drivers/misc/rp1/rp1_pci.c b/drivers/misc/rp1/rp1_pci.c > > > > > > new file mode 100644 > > > > > > index 000000000000..3e8ba3fa7fd5 > > > > > > --- /dev/null > > > > > > +++ b/drivers/misc/rp1/rp1_pci.c > > > > > > @@ -0,0 +1,305 @@ > > > > > > +// SPDX-License-Identifier: GPL-2.0 > > > > > > +/* > > > > > > + * Copyright (c) 2018-24 Raspberry Pi Ltd. > > > > > > + * All rights reserved. > > > > > > + */ > > > > > > + > > > > > > +#include > > > > > > +#include > > > > > > +#include > > > > > > +#include > > > > > > +#include > > > > > > +#include > > > > > > +#include > > > > > > +#include > > > > > > +#include > > > > > > +#include > > > > > > + > > > > > > +#include "rp1_pci.h" > > > > > > > > > > Why does a self-contained .c file need a .h file? Please put it all in > > > > > here. > > > > > > > > I agree with you. Indeed, the very first version of this patch had the header > > > > file placed inside the .c, but I received concerns about it and some advice to > > > > do it differently, as you can see here: > > > > https://lore.kernel.org/all/ZtWDpaqUG9d9yPPf@apocalypse/ > > > > so I've changed it accordingly in V2. So right now I'm not sure what the > > > > acceptable behaviour should be ... > > > > > > It's a pretty simple rule: > > > Only use a .h file if multiple .c files need to see the symbol. > > > > > > So no .h file is needed here. > > > > Perfect, I'll revert back that two lines to V1 then. Please be aware > > though that this will trigger the following checkpatch warning: > > > > WARNING: externs should be avoided in .c files > > Well where are those externs defined at? Shouldn't there be a .h file > for them somewhere in the tree if they really are global? Those symbols are deined in drivers/misc/rp1/rp1-pci.dtbo.S (added by this patchset) and created by cmd_wrap_S_dtb in scripts/Makefile.lib. They are just placeholders that contains rp1-pci.dtbo as a binary blob, in order for the driver (rp1_pci.c) to be able to use the binary buffer representing the overlay and address it from the driver probe function. So there's no other reference from outside rp1_pci.c to those two symbols. In comparison, this is the very same approach used by a recently accepted patch involving drivers/misc/lan966x_pci.c, which also has the two externs in it and triggers the same checkpatch warning. Many thanks, Andrea > > thanks, > > greg k-h