From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DFEECC3F2CD for ; Sat, 29 Feb 2020 23:13:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BE19524672 for ; Sat, 29 Feb 2020 23:13:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727506AbgB2XNS (ORCPT ); Sat, 29 Feb 2020 18:13:18 -0500 Received: from baldur.buserror.net ([165.227.176.147]:54310 "EHLO baldur.buserror.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727170AbgB2XNS (ORCPT ); Sat, 29 Feb 2020 18:13:18 -0500 Received: from [2601:449:8480:af0:12bf:48ff:fe84:c9a0] by baldur.buserror.net with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1j8BI4-0002LE-3Z; Sat, 29 Feb 2020 17:13:01 -0600 Message-ID: From: Scott Wood To: =?UTF-8?Q?=E7=8E=8B=E6=96=87=E8=99=8E?= Cc: wangwenhu , Kumar Gala , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, trivial@kernel.org, Rai Harninder Date: Sat, 29 Feb 2020 17:12:58 -0600 In-Reply-To: References: Organization: Red Hat Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.1 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 2601:449:8480:af0:12bf:48ff:fe84:c9a0 X-SA-Exim-Rcpt-To: wenhu.wang@vivo.com, wenhu.pku@gmail.com, galak@kernel.crashing.org, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, trivial@kernel.org, harninder.rai@nxp.com X-SA-Exim-Mail-From: oss@buserror.net Subject: Re: Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM configurable X-SA-Exim-Version: 4.2.1 (built Tue, 02 Aug 2016 21:08:31 +0000) X-SA-Exim-Scanned: Yes (on baldur.buserror.net) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2020-01-21 at 14:38 +0800, 王文虎 wrote: > 发件人：Scott Wood > 发送日期：2020-01-21 13:49:59 > 收件人："王文虎" > 抄送人：wangwenhu ,Kumar Gala ,B > enjamin Herrenschmidt ,Paul Mackerras < > paulus@samba.org>,Michael Ellerman , > linuxppc-dev@lists.ozlabs.org,linux-kernel@vger.kernel.org, > trivial@kernel.org,Rai Harninder > 主题：Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM configurable>On > Tue, 2020-01-21 at 13:20 +0800, 王文虎 wrote: > > > From: Scott Wood > > > Date: 2020-01-21 11:25:25 > > > To: wangwenhu ,Kumar Gala < > > > galak@kernel.crashing.org>, > > > Benjamin Herrenschmidt ,Paul Mackerras < > > > paulus@samba.org>,Michael Ellerman , > > > linuxppc-dev@lists.ozlabs.org,linux-kernel@vger.kernel.org > > > Cc: trivial@kernel.org,wenhu.wang@vivo.com,Rai Harninder < > > > harninder.rai@nxp.com> > > > Subject: Re: [PATCH] powerpc/Kconfig: Make FSL_85XX_CACHE_SRAM > > > configurable>On Mon, 2020-01-20 at 06:43 -0800, wangwenhu wrote: > > > > > From: wangwenhu > > > > > > > > > > When generating .config file with menuconfig on Freescale BOOKE > > > > > SOC, FSL_85XX_CACHE_SRAM is not configurable for the lack of > > > > > description in the Kconfig field, which makes it impossible > > > > > to support L2Cache-Sram driver. Add a description to make it > > > > > configurable. > > > > > > > > > > Signed-off-by: wangwenhu > > > > > > > > The intent was that drivers using the SRAM API would select the > > > > symbol. What > > > > is the use case for selecting it manually? > > > > > > > > > > With a repository of multiple products(meaning different defconfigs) and > > > multiple > > > developers, the Kconfigs of the Kernel Source Tree change frequently. So > > > the > > > "make menuconfig" > > > process is needed for defconfigs' re-generating or updating for the > > > complexity of dependencies > > > between different features defined in the Kconfigs. > > > > That doesn't answer my question of how the SRAM code would be useful other > > than to some other driver that uses the API (which would use > > "select"). There > > is no userspace API. You could use the kernel command line to configure > > the > > SRAM but you need to get the address of it for it to be useful. > > > > Like you've asked below, via /dev/mem or direct calling within the Kernel. > And they are not submitted yes, under development. If they are calling within the kernel, then whatever driver that is should select FSL_85XX_CACHE_SRAM. Directly accessing /dev/mem without any way for the kernel to advertise where it is or which parts of SRAM are available for use sounds like a bad idea. -Scott