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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 601B0C43463 for ; Fri, 18 Sep 2020 12:25:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2123922208 for ; Fri, 18 Sep 2020 12:25:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726126AbgIRMY5 (ORCPT ); Fri, 18 Sep 2020 08:24:57 -0400 Received: from mga05.intel.com ([192.55.52.43]:55411 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725955AbgIRMY5 (ORCPT ); Fri, 18 Sep 2020 08:24:57 -0400 IronPort-SDR: +Em5LBh7D+Ae3TkVqFnjFKRCspsw6mzjK2Bv0+VCTlB+n2UzgvwbuzRqOyRGA2dkP/oJnPvR3O J4Z+egc3mYzQ== X-IronPort-AV: E=McAfee;i="6000,8403,9747"; a="244758112" X-IronPort-AV: E=Sophos;i="5.77,274,1596524400"; d="scan'208";a="244758112" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Sep 2020 05:24:56 -0700 IronPort-SDR: Su8fdFmcA3/oHfW7dwfrBVBZ5nPDpHh2UfBATeDBd5RZdgyftr9w2pkedjNDSbwRoeTSm7Zxfy /wLgwMkP6GbA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,274,1596524400"; d="scan'208";a="336787905" Received: from smile.fi.intel.com (HELO smile) ([10.237.68.40]) by orsmga008.jf.intel.com with ESMTP; 18 Sep 2020 05:24:53 -0700 Received: from andy by smile with local (Exim 4.94) (envelope-from ) id 1kJFNN-00HZtB-Sl; Fri, 18 Sep 2020 15:20:29 +0300 Date: Fri, 18 Sep 2020 15:20:29 +0300 From: Andy Shevchenko To: "Reddy, MallikarjunaX" Cc: dmaengine@vger.kernel.org, vkoul@kernel.org, devicetree@vger.kernel.org, robh+dt@kernel.org, linux-kernel@vger.kernel.org, chuanhua.lei@linux.intel.com, cheol.yong.kim@intel.com, qi-ming.wu@intel.com, malliamireddy009@gmail.com, peter.ujfalusi@ti.com Subject: Re: [PATCH v6 2/2] Add Intel LGM soc DMA support. Message-ID: <20200918122029.GX3956970@smile.fi.intel.com> References: <748370a51af0ab768e542f1537d1aa3aeefebe8a.1599605765.git.mallikarjunax.reddy@linux.intel.com> <20200909111424.GQ1891694@smile.fi.intel.com> <36a42016-3260-3933-bbf9-9203c4124115@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <36a42016-3260-3933-bbf9-9203c4124115@linux.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Fri, Sep 18, 2020 at 11:42:54AM +0800, Reddy, MallikarjunaX wrote: > On 9/9/2020 7:14 PM, Andy Shevchenko wrote: > > On Wed, Sep 09, 2020 at 07:07:34AM +0800, Amireddy Mallikarjuna reddy wrote: ... > > > + help > > > + Enable support for intel Lightning Mountain SOC DMA controllers. > > > + These controllers provide DMA capabilities for a variety of on-chip > > > + devices such as SSC, HSNAND and GSWIP. > > And how module will be called? >  are you expecting to include 'default y' ? I'm expecting to see something like "if you choose M the module will be called bla-foo-bar." Look at the existing examples in the kernel. ... > > > +ldma_update_bits(struct ldma_dev *d, u32 mask, u32 val, u32 ofs) > > > +{ > > > + u32 old_val, new_val; > > > + > > > + old_val = readl(d->base + ofs); > > > + new_val = (old_val & ~mask) | (val & mask); > > With bitfield.h you will have this as u32_replace_bits(). > -  new_val = (old_val & ~mask) | (val & mask); > + new_val = old_val; > + u32_replace_bits(new_val, val, mask); > > I think in this function we cant use this because of compilation issues > thrown by bitfield.h . Expecting 2nd and 3rd arguments as constant numbers > not as type variables. > > ex: > u32_replace_bits(val, 0, IPA_REG_ENDP_ROUTER_HASH_MSK_ALL); How comes these are constants? In the above you have a function which does r-m-w approach to the register. It should be something like old = read(); new = u32_replace_bits(old, ...); write(new); > ./include/linux/bitfield.h:131:3: error: call to '__field_overflow' declared > with attribute error: value doesn't fit into mask >    __field_overflow();     \ >    ^~~~~~~~~~~~~~~~~~ > > ./include/linux/bitfield.h:119:3: error: call to '__bad_mask' declared with > attribute error: bad bitfield mask >    __bad_mask(); >    ^~~~~~~~~~~~ So, even with constants u32_replace_bits() must work. Maybe you didn't get how? > > > + if (new_val != old_val) > > > + writel(new_val, d->base + ofs); > > > +} ... > > > + /* High 4 bits */ > > Why only 4? > this is higher 4 bits of 36 bit addressing.. Make it clear in the comment. ... > > > +device_initcall(intel_ldma_init); > > Each _initcall() in general should be explained. > ok. is it fine? > > /* Perform this driver as device_initcall to make sure initialization > happens >  * before its dma clients of some are platform specific. make sure to > provice >  * registered dma channels and dma capabilities to client before their >  * initialization. >  */ /* * Just follow proper multi-line comment style. * And use dma -> DMA. */ -- With Best Regards, Andy Shevchenko