From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sudeep Holla Subject: Re: [PATCH] of: base: upgrade initcall level of of_init from core to pure Date: Wed, 13 May 2015 11:03:50 +0100 Message-ID: <55532186.5060803@arm.com> References: <1431452282-10207-1-git-send-email-sudeep.holla@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Rob Herring Cc: Sudeep Holla , "linux-kernel@vger.kernel.org" , "devicetree@vger.kernel.org" , "grant.likely@linaro.org" , Rob Herring , Benjamin Herrenschmidt , Greg Kroah-Hartman List-Id: devicetree@vger.kernel.org On 12/05/15 23:55, Rob Herring wrote: > On Tue, May 12, 2015 at 12:38 PM, Sudeep Holla wrote: >> Commit 5590f3196b29 ("drivers/core/of: Add symlink to device-tree from >> devices with an OF node") adds the symlink `of_node` for each device >> pointing to it's device tree node while creating/initialising it. >> >> However the devicetree sysfs is created and setup in of_init which is >> executed at core_initcall level. For all the devices created at the core >> initcall before of_init, the following error is thrown: >> "Error -2(-ENOENT) creating of_node link" > > What devices have you seen the problem with? I'd rather see if those > devices could now be moved later. > Yes that's exactly what I attempted first after seeing the issue, but failed miserably due to the dependency mentioned below. It's on vexpress platforms with the following initcall sequence: 1. core - vexpress system control registers block(sysreg) 2. postcore - vexpress configuration controllers(config-bridge) 3. arch - customize_machine->of_platform_populate of_platform_populate creates amba_devices which need clocks and depend on the vexpress-config and clocks which in turn depends on vexpress-sysreg I would like to know if with commit 5590f3196b29 are we mandating all the device creation to be done only after core_initcall or is it OK get the errors mentioned above and ignore them as harmless as the comment in the code states: "An error here doesn't warrant bringing down the device" >> Since the core_initcall is the earliest point where devices get >> registered, push initcall level of of_init from core to pure so that >> the devicetree sysfs is ready before any devices are registered. > > Read the definition of pure: > > * A "pure" initcall has no dependencies on anything else, and purely > * initializes variables that couldn't be statically initialized. > Yes I read and was bit hesitant initially to do this change, but found no better way. I posted mainly to discuss other possibilities to solve the issue. Regards, Sudeep