From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759333AbaGCRgR (ORCPT ); Thu, 3 Jul 2014 13:36:17 -0400 Received: from bear.ext.ti.com ([192.94.94.41]:38165 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751285AbaGCRgP (ORCPT ); Thu, 3 Jul 2014 13:36:15 -0400 Message-ID: <53B59471.30703@ti.com> Date: Thu, 3 Jul 2014 12:35:45 -0500 From: Suman Anna User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Ohad Ben-Cohen CC: Mark Rutland , Kumar Gala , Tony Lindgren , Josh Cartwright , Bjorn Andersson , "linux-kernel@vger.kernel.org" , "linux-omap@vger.kernel.org" , "devicetree@vger.kernel.org" , linux-arm Subject: Re: [PATCHv5 04/15] hwspinlock/core: add common OF helpers References: <1398904476-26200-1-git-send-email-s-anna@ti.com> <1398904476-26200-5-git-send-email-s-anna@ti.com> <53B47626.4040506@ti.com> In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Ohad, On 07/03/2014 02:15 AM, Ohad Ben-Cohen wrote: > Hi Suman, > > On Thu, Jul 3, 2014 at 12:14 AM, Suman Anna wrote: >>> Do we have a use case today that require the xlate() method? >>> >>> If not, let's remove it as we could always add it back if some new >>> hardware shows up that needs it. >> >> The xlate() method is to support the phandle + args specifier way of >> requesting hwlocks, platform implementations are free to implement their >> own xlate functions, but the above supports the simplest case of >> controller + relative lock index within controller. > > Do we have a use case for a different implementation other than the > simplest case? If not, it seems to me this will just become redundant > boilerplate code (every platform will use the simple xlate method). Not at the moment, with the existing platform implementations. So, if I understand you correctly, you are asking to leave out the xlate ops and make the of_hwspin_lock_simple_xlate() internal until a need for an xlate method arises. This also means, we only support a value of 1 for #hwlock-cells. > >> This function again is to support the phandle + args specifier way of >> requesting hwlocks, the hwspin_lock_request_specific() is invoked >> internally within this function, so we are still reusing the actual >> request code other than handling the DT parsing portion. If we go back >> to using global locks in client hwlocks property, we don't need a >> of_hwspin_lock_get_id(), the same can be achieved using the existing DT >> function, of_property_read_u32_index(). > > I think you may have misunderstood me, sorry. I'm ok with the phandle > + args specifier. I just think we can use it, together with the > base_id property, to infer the global lock id from the DT data. Aah ok, its minor code rearrangement for what you are asking - I just need to leave out invoking the request_specific invocation in the OF request specific existing function, just return the global id and let the client users call the normal request_specific API themselves. But, that would mean DT-based client users would have to invoke two function calls to request a hwspinlock. We already have an API to get the lock id given a hwspinlock - hwspin_lock_get_id(), so I added the OF API for requesting a lock directly rather than giving an OF API for getting the lock id. This is in keeping in convention with what other drivers do normally - a regular get and an OF get. I can modify it if you still prefer the OF API for getting a global lock id, but I feel its a burden for client users. Also, do you prefer an open property-name in client users (like I am doing at the moment) or imposing a standard property name "hwlocks"? regards Suman > This is not only a must to support heterogenous multi-processing systems, > it will also substantially simplify the code. > > Thanks, > Ohad. >