From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Boyd Subject: Re: use IORESOURCE_REG resource type for non-translatable addresses in DT Date: Tue, 29 Jul 2014 18:07:36 -0700 Message-ID: <53D84558.7060406@codeaurora.org> References: <53D788A7.4020303@mm-sol.com> <3794875.CZFbAag5Sv@wuerfel> <53D7AA72.6010309@mm-sol.com> <20140729234522.E9FF1C40738@trevor.secretlab.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from smtp.codeaurora.org ([198.145.11.231]:59616 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752449AbaG3BHi (ORCPT ); Tue, 29 Jul 2014 21:07:38 -0400 In-Reply-To: <20140729234522.E9FF1C40738@trevor.secretlab.ca> Sender: linux-arm-msm-owner@vger.kernel.org List-Id: linux-arm-msm@vger.kernel.org To: Grant Likely Cc: Stanimir Varbanov , Arnd Bergmann , Rob Herring , Rob Herring , Lee Jones , "linux-arm-msm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "devicetree@vger.kernel.org" , linux-arm-kernel@lists.infradead.org, Mark Brown On 07/29/14 16:45, Grant Likely wrote: > On Tue, 29 Jul 2014 17:06:42 +0300, Stanimir Varbanov wrote: >> >> This was just an example. Of course it has many issues and probaly it is >> wrong:) The main goal was to understand does IORESOURCE_REG resource >> type and parsing the *reg* properties for non-translatable addresses are >> feasible. And also does it acceptable by community and OF platform >> maintainers. > The use case is actually very different from of_address_to_resource or > of_get_address() because those APIs explicitly return physical memory > addresses from the CPU perspective. It makes more sense to create a new > API that doesn't attempt to translate the reg address. Alternately, a > new API that only translates upto a given parent node. The most important thing is that platform_get_resource{_by_name}(&pdev, IORESOURCE_REG, n) returns the reg property and optional size encoded into a struct resource. I think Rob is suggesting we circumvent the entire of_address_to_resource() path and do some if (IS_ENABLED(CONFIG_OF) && type == IORESOURCE_REG) check in platform_get_resource() to package up the reg property into a struct resource. That should work. It sounds like you think partially translating addresses is risky though. Fair enough. Perhaps we should call WARN() if someone tries to call platform_get_resource() with IORESOURCE_REG and the parent node has a ranges property that isn't a one-to-one conversion. That way if we want to do something like this we can. pmic@0 { #address-cells = <1>; #size-cells = <0>; reg = <0>; regulators { ranges; #address-cells = <1>; #size-cells = <0>; regulator@40 { reg = <0x40>; }; regulator@50 { reg = <0x50>; } }; }; -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation