From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Subject: [02/14] dmaengine: dma-jz4780: Separate chan/ctrl registers From: Rob Herring Message-Id: <20180716212852.GA6323@rob-hp-laptop> Date: Mon, 16 Jul 2018 15:28:52 -0600 To: Paul Burton Cc: Vinod , Mark Rutland , Paul Cercueil , Ralf Baechle , James Hogan , Zubair Lutfullah Kakakhel , Mathieu Malaterre , Daniel Silsby , dmaengine@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@linux-mips.org List-ID: T24gV2VkLCBKdWwgMTEsIDIwMTggYXQgMDQ6Mjc6MTVQTSAtMDcwMCwgUGF1bCBCdXJ0b24gd3Jv dGU6Cj4gSGkgVmlub2QsCj4gCj4gT24gV2VkLCBKdWwgMTEsIDIwMTggYXQgMDU6NDY6NTVQTSAr MDUzMCwgVmlub2Qgd3JvdGU6Cj4gPiA+ID4gPiAgLQlqemRtYS0+YmFzZSA9IGRldm1faW9yZW1h cF9yZXNvdXJjZShkZXYsIHJlcyk7Cj4gPiA+ID4gPiAgLQlpZiAoSVNfRVJSKGp6ZG1hLT5iYXNl KSkKPiA+ID4gPiA+ICAtCQlyZXR1cm4gUFRSX0VSUihqemRtYS0+YmFzZSk7Cj4gPiA+ID4gPiAg KwlqemRtYS0+Y2huX2Jhc2UgPSBkZXZtX2lvcmVtYXBfcmVzb3VyY2UoZGV2LCByZXMpOwo+ID4g PiA+ID4gICsJaWYgKElTX0VSUihqemRtYS0+Y2huX2Jhc2UpKQo+ID4gPiA+ID4gICsJCXJldHVy biBQVFJfRVJSKGp6ZG1hLT5jaG5fYmFzZSk7Cj4gPiA+ID4gPiAgKwo+ID4gPiA+ID4gICsJcmVz ID0gcGxhdGZvcm1fZ2V0X3Jlc291cmNlKHBkZXYsIElPUkVTT1VSQ0VfTUVNLCAxKTsKPiA+ID4g PiA+ICArCWlmICghcmVzKSB7Cj4gPiA+ID4gPiAgKwkJZGV2X2VycihkZXYsICJmYWlsZWQgdG8g Z2V0IEkvTyBtZW1vcnlcbiIpOwo+ID4gPiA+ID4gICsJCXJldHVybiAtRUlOVkFMOwo+ID4gPiA+ ID4gICsJfQo+ID4gPiA+IAo+ID4gPiA+IG9rYXkgYW5kIHRoaXMgYnJlYWtzIGlmIHlvdSBoYXBw ZW4gdG8gZ2V0IHByb2JlZCBvbiBvbGRlciBEVC4gSSB0aGluayBEVAo+ID4gPiA+IGlzIHRyZWF0 ZWQgYXMgQUJJIHNvIHlvdSBuZWVkIHRvIGNvbnRpbnVlIHN1cHBvcnQgb2xkZXIgbWV0aG9kIHdo aWxlCj4gPiA+ID4gZmluZGluZyBpZiBEVCBoYXMgc3BsaXQgcmVzb3VyY2VzCj4gPiA+IAo+ID4g PiBTZWUgbXkgcmVzcG9uc2UgdG8gUHJhc2FubmFLdW1hci4gQWxsIHRoZSBJbmdlbmljLWJhc2Vk IGJvYXJkcyBkbyBjb21waWxlCj4gPiA+IHRoZSBkZXZpY2V0cmVlIHdpdGhpbiB0aGUga2VybmVs LCBzbyBJIHRoaW5rIGl0J3Mgc3RpbGwgZmluZSB0byBhZGQgYnJlYWtpbmcKPiA+ID4gY2hhbmdl cy4gSSdsbCB3YWl0IG9uIEBSb2IgdG8gZ2l2ZSBoaXMgcG9pbnQgb2YgdmlldyBvbiB0aGlzLCB0 aG91Z2guCj4gPiA+IAo+ID4gPiAoSXQncyBub3Qgc29tZXRoaW5nIGhhcmQgdG8gY2hhbmdlLCBi dXQgSSdkIGxpa2UgdG8ga25vdyB3aGF0J3MgdGhlIHBvbGljeQo+ID4gPiBpbiB0aGF0IGNhc2Uu IEkgaGF2ZSBvdGhlciBEVC1icmVha2luZyBwYXRjaGVzIHRvIHN1Ym1pdCkKPiA+IAo+ID4gVGhl IHBvbGljeSBpcyB0aGF0IERUIGlzIGFuIEFCSSBhbmQgc2hvdWxkIG5vdCBicmVhayA6KQo+IAo+ IEkgdGhpbmsgaW4gZ2VuZXJhbCB0aGF0J3MgYSBnb29kIHBvbGljeSB0byBoYXZlIGZvciBjb21w YXRpYmlsaXR5LCBidXQKPiBpZiBpdCdzIGtub3duIGZvciBjZXJ0YWluIHRoYXQgdGhlIERUIGZv ciBhbGwgdXNlcnMgb2YgYSBkcml2ZXIgaXMKPiBhbHdheXMgYnVpbHQgaW50byB0aGUga2VybmVs IHRoZW4gSSBkb24ndCBzZWUgd2h5IHdlIHNob3VsZG4ndCBmZWVsIGZyZWUKPiB0byBjaGFuZ2Ug YSBiaW5kaW5nLiBJIGFncmVlIHdpdGggUGF1bCB0aGF0IGl0J2QgYmUgaW50ZXJlc3RpbmcgdG8g aGVhcgo+IHRoZSBEVCBiaW5kaW5nIG1haW50YWluZXJzIHRha2Ugb24gdGhpcy4KCklmIHRoZSBw bGF0Zm9ybSBtYWludGFpbmVycyAoYW5kIHRoZWlyIHVzZXJzKSBkb24ndCBjYXJlLCB0aGVuIEkg ZG9uJ3QgCmhhdmUgYW4gaXNzdWUgd2l0aCB0aGUgY2hhbmdlLiBJdCBzaG91bGQgc3RpbGwgYmUg YW4gZXhjZXB0aW9uIGFuZCBub3QgCmp1c3QgYW55IGNoYW5nZSBnb2VzLiBUaGUgY29tbWl0IG1l c3NhZ2Ugc2hvdWxkIHN0aWxsIGhpZ2hsaWdodCB0aGF0IApjb21wYXRpYmlsaXR5IGlzIGJlaW5n IGJyb2tlbiBhbmQgd2h5LgoKUm9iCi0tLQpUbyB1bnN1YnNjcmliZSBmcm9tIHRoaXMgbGlzdDog c2VuZCB0aGUgbGluZSAidW5zdWJzY3JpYmUgZG1hZW5naW5lIiBpbgp0aGUgYm9keSBvZiBhIG1l c3NhZ2UgdG8gbWFqb3Jkb21vQHZnZXIua2VybmVsLm9yZwpNb3JlIG1ham9yZG9tbyBpbmZvIGF0 ICBodHRwOi8vdmdlci5rZXJuZWwub3JnL21ham9yZG9tby1pbmZvLmh0bWwK From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Mon, 16 Jul 2018 23:29:10 +0200 (CEST) Received: from mail-oi0-f68.google.com ([209.85.218.68]:35579 "EHLO mail-oi0-f68.google.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S23993024AbeGPV3Am-z96 (ORCPT ); Mon, 16 Jul 2018 23:29:00 +0200 Received: by mail-oi0-f68.google.com with SMTP id i12-v6so77644869oik.2; Mon, 16 Jul 2018 14:29:00 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=Z4LTUphqrMF2ZUQkliDnej/gPLyoQjbEBwgTd9g6gvo=; b=QnzT055baTYCMSJHzaQbTSZKPcTm82CMBWck3iwS1epignnkQECmdP7wnjGmykhzM2 uGLgYmwtM7X6Yyioh0ZYQFXNwz25Gd8s9vGGhY4QsZLjmMr3lpjK+JaHXj44/MAaLXnq e0GE5sOcOCp82Qf+3ZF7b4p0+L0ZzEhOxbLa93UqHLq/szgiFvHV2uaU3/Fb9eV7boKX o0H+X0hwEKAZL2sUzxU3zGwSJHiJG1WoV8GOr1hqNWULq2cmjUSqr1Ed0TBw/j3SjKkY hn7+nAxKnDxkz9+n2wB9EMLzH2b2pNtkn9IUUEBVFJy6wKf4gFElgre6LbJwPF9KZLjM 2z4Q== X-Gm-Message-State: AOUpUlErzflH8SI9I2Idmc9olxPisHZSw64rmE3CUF45I5+Rq962pVAQ B4sPfrLUg7mf2tB+euyodA== X-Google-Smtp-Source: AAOMgpeZD5rBFhgJQpDu4ehuJR2dtHJPUmFlHhzDv1eC+rbBSiwkybQp+GHo4PbeB0kWRShOBnWs8w== X-Received: by 2002:aca:a64d:: with SMTP id p74-v6mr1034454oie.149.1531776534378; Mon, 16 Jul 2018 14:28:54 -0700 (PDT) Received: from localhost (24-223-123-72.static.usa-companies.net. [24.223.123.72]) by smtp.gmail.com with ESMTPSA id r133-v6sm30021629oia.33.2018.07.16.14.28.53 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 16 Jul 2018 14:28:53 -0700 (PDT) Date: Mon, 16 Jul 2018 15:28:52 -0600 From: Rob Herring To: Paul Burton Cc: Vinod , Mark Rutland , Paul Cercueil , Ralf Baechle , James Hogan , Zubair Lutfullah Kakakhel , Mathieu Malaterre , Daniel Silsby , dmaengine@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@linux-mips.org Subject: Re: [PATCH 02/14] dmaengine: dma-jz4780: Separate chan/ctrl registers Message-ID: <20180716212852.GA6323@rob-hp-laptop> References: <20180703123214.23090-1-paul@crapouillou.net> <20180703123214.23090-3-paul@crapouillou.net> <20180709170359.GI22377@vkoul-mobl> <1531237019.17118.1@crapouillou.net> <20180711121655.GS3219@vkoul-mobl> <20180711232715.djxrbgmcski5xtjp@pburton-laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180711232715.djxrbgmcski5xtjp@pburton-laptop> User-Agent: Mutt/1.9.4 (2018-02-28) Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 64864 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: robh@kernel.org Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips On Wed, Jul 11, 2018 at 04:27:15PM -0700, Paul Burton wrote: > Hi Vinod, > > On Wed, Jul 11, 2018 at 05:46:55PM +0530, Vinod wrote: > > > > > - jzdma->base = devm_ioremap_resource(dev, res); > > > > > - if (IS_ERR(jzdma->base)) > > > > > - return PTR_ERR(jzdma->base); > > > > > + jzdma->chn_base = devm_ioremap_resource(dev, res); > > > > > + if (IS_ERR(jzdma->chn_base)) > > > > > + return PTR_ERR(jzdma->chn_base); > > > > > + > > > > > + res = platform_get_resource(pdev, IORESOURCE_MEM, 1); > > > > > + if (!res) { > > > > > + dev_err(dev, "failed to get I/O memory\n"); > > > > > + return -EINVAL; > > > > > + } > > > > > > > > okay and this breaks if you happen to get probed on older DT. I think DT > > > > is treated as ABI so you need to continue support older method while > > > > finding if DT has split resources > > > > > > See my response to PrasannaKumar. All the Ingenic-based boards do compile > > > the devicetree within the kernel, so I think it's still fine to add breaking > > > changes. I'll wait on @Rob to give his point of view on this, though. > > > > > > (It's not something hard to change, but I'd like to know what's the policy > > > in that case. I have other DT-breaking patches to submit) > > > > The policy is that DT is an ABI and should not break :) > > I think in general that's a good policy to have for compatibility, but > if it's known for certain that the DT for all users of a driver is > always built into the kernel then I don't see why we shouldn't feel free > to change a binding. I agree with Paul that it'd be interesting to hear > the DT binding maintainers take on this. If the platform maintainers (and their users) don't care, then I don't have an issue with the change. It should still be an exception and not just any change goes. The commit message should still highlight that compatibility is being broken and why. Rob