From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hiroshi Doyu Subject: Re: [PATCHv3 1/4] ARM: tegra: Add Tegra AHB driver Date: Mon, 7 May 2012 09:06:19 +0300 Message-ID: <20120507090619.90932b9f67a4b672abeb887f@nvidia.com> References: <1336061147-10245-1-git-send-email-hdoyu@nvidia.com> <4FA2C34F.5060406@wwwdotorg.org> <20120504.091736.839941449020176796.hdoyu@nvidia.com> <4FA40878.7070709@wwwdotorg.org> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4FA40878.7070709-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Stephen Warren Cc: "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "balbi-l0cyMroinI0@public.gmane.org" , "arnd-r2nGTMty4D4@public.gmane.org" , "ccross-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org" , "olof-nZhT3qVonbNeoWH0uzbU5w@public.gmane.org" , "linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org" , "grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org" , "rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org" , "gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org" , "ohad-Ix1uc/W3ht7QT0dZR+AlfA@public.gmane.org" , "linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" , "linville-2XuSBdqkA4R54TAoqtyWWQ@public.gmane.org" , "myungjoo.ham-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org" List-Id: devicetree@vger.kernel.org On Fri, 4 May 2012 18:48:56 +0200 Stephen Warren wrote: > On 05/04/2012 12:17 AM, Hiroshi Doyu wrote: > > Stephen Warren wrote at Thu, 3 May 2012 19:41:35 +0200: > >> On 05/03/2012 10:05 AM, Hiroshi DOYU wrote: > >>> Tegra AHB Bus conforms to the AMBA Specification (Rev 2.0) Advanced > >>> High-performance Bus (AHB) architecture. > ... > >>> +static int __init tegra_ahb_module_init(void) > >>> +{ > >>> + return platform_driver_register(&tegra_ahb_driver); > >>> +} > >>> +postcore_initcall(tegra_ahb_module_init); > >> > >> Can this be a module_init() instead of postcore_initcall()? > > > > Since this driver configures prefetch size from AHB client devices, > > it's better to make this driver available before other AHB client > > drivers get ready. So "postcore_initcall()" seems to make sense if > > there's no other better initcall. > > I believe this only affects when the driver is registered and has no > influence over when the device itself is probed. > > When booting with board files rather than DT, it was possible to > register drivers and platform devices early using various initcalls to > control the order. However, with DT, I believe all the devices are > instantiated from DT at the same time (well, one by one in whatever > order as the DT is parsed), so the time when the driver is registered > isn't relevant. > > So, if the other AHB devices really need this AHB driver to initialize > first, you'd better move all the AHB devices inside the AHB node in DT, > so that the AHB driver can influence when the children get probed. > Still, I'd suggest leaving that to a later patch, since everything > clearly works fine right now without this driver even existing. Ok, I'll use module_platform_driver(tegra_ahb_driver). These order would be revisited.