linux-kernel - Re: [PATCH v8 08/13] misc: rp1: RaspberryPi RP1 misc driver

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Z_5-Jjbu6XoHGmxN@apocalypse>
Date: Tue, 15 Apr 2025 17:41:26 +0200
From: Andrea della Porta <andrea.porta@...e.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Herve Codina <herve.codina@...tlin.com>,
	Andrea della Porta <andrea.porta@...e.com>,
	Michael Turquette <mturquette@...libre.com>,
	Stephen Boyd <sboyd@...nel.org>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Florian Fainelli <florian.fainelli@...adcom.com>,
	Broadcom internal kernel review list <bcm-kernel-feedback-list@...adcom.com>,
	Lorenzo Pieralisi <lpieralisi@...nel.org>,
	Krzysztof Wilczynski <kw@...ux.com>,
	Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>, Bartosz Golaszewski <brgl@...ev.pl>,
	Derek Kiernan <derek.kiernan@....com>,
	Dragan Cvetic <dragan.cvetic@....com>,
	Arnd Bergmann <arnd@...db.de>,
	Saravana Kannan <saravanak@...gle.com>, linux-clk@...r.kernel.org,
	devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
	linux-gpio@...r.kernel.org, Masahiro Yamada <masahiroy@...nel.org>,
	Stefan Wahren <wahrenst@....net>,
	Luca Ceresoli <luca.ceresoli@...tlin.com>,
	Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
	Andrew Lunn <andrew@...n.ch>, Phil Elwell <phil@...pberrypi.com>,
	Dave Stevenson <dave.stevenson@...pberrypi.com>,
	kernel-list@...pberrypi.com
Subject: Re: [PATCH v8 08/13] misc: rp1: RaspberryPi RP1 misc driver

Hi Greg,

On 17:14 Tue 15 Apr     , Greg Kroah-Hartman wrote:
> On Tue, Apr 15, 2025 at 04:55:05PM +0200, Herve Codina wrote:
> > Hi Greg,
> > 
> > On Tue, 15 Apr 2025 16:06:43 +0200
> > Greg Kroah-Hartman <gregkh@...uxfoundation.org> wrote:
> > 
> > > On Wed, Mar 19, 2025 at 10:52:29PM +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.  
> > > 
> > > So shouldn't this be using the auxbus code?  That's designed to "split
> > > up" PCI devices such that you can share them this way.
> > > 
> > > Or did that get rejected somewhere previously?
> > > 
> > 
> > It doesn't use auxbus probably for the exact same reason that the
> > one given for the LAN966x PCI device driver [0] and [1].
> > 
> > Avoid all boiler plate needed with auxbus whereas drivers already exist
> > as platform drivers. Internal devices are handled by those platform drivers.
> > Those devi just need to be described as platform devices and device-tree is
> > fully relevant for that description.
> > 
> > [0] https://lore.kernel.org/all/CAL_Jsq+1r3SSaXupdNAcXO-4rcV-_3_hwh0XJaBsB9fuX5nBCQ@mail.gmail.com/
> > [1] https://lore.kernel.org/all/Y9kuxrL3XaCG+blk@kroah.com/
> 
> I really hate creating platform devices below a PCI device, so I'll keep
> complaining about this every time people try to do it.

I agree with you, but as Herve has already pointed out this would mean incurring
in significant work to adapt drivers for all the peripherals (there are quite a
few), while with this approach they would be left untouched.

Many thanks,
Andrea

> 
> thanks,
> 
> greg k-h