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: [v2] dmaengine: axi-dmac: Request IRQ with IRQF_SHARED From: Vinod Koul Message-Id: <20180428051043.GG6014@localhost> Date: Sat, 28 Apr 2018 10:40:43 +0530 To: Lars-Peter Clausen Cc: Moritz Fischer , Linux Kernel Mailing List , dmaengine@vger.kernel.org, dan.j.williams@intel.com List-ID: T24gRnJpLCBBcHIgMjcsIDIwMTggYXQgMDU6MTg6MjlQTSArMDIwMCwgTGFycy1QZXRlciBDbGF1 c2VuIHdyb3RlOgo+IE9uIDA0LzI3LzIwMTggMDU6MTUgUE0sIE1vcml0eiBGaXNjaGVyIHdyb3Rl Ogo+ID4gSGkgVmlub2QsCj4gPiAKPiA+IE9uIEZyaSwgQXByIDI3LCAyMDE4IGF0IDEyOjA4IEFN LCBWaW5vZCBLb3VsIDx2aW5vZC5rb3VsQGludGVsLmNvbT4gd3JvdGU6Cj4gPj4gT24gRnJpLCBB cHIgMjcsIDIwMTggYXQgMDg6NTM6MzlBTSArMDIwMCwgTGFycy1QZXRlciBDbGF1c2VuIHdyb3Rl Ogo+ID4+PiBPbiAwNC8yNy8yMDE4IDA3OjExIEFNLCBWaW5vZCBLb3VsIHdyb3RlOgo+ID4+Pj4g T24gVGh1LCBBcHIgMjYsIDIwMTggYXQgMTA6NDA6MDBBTSAtMDcwMCwgTW9yaXR6IEZpc2NoZXIg d3JvdGU6Cj4gPj4+Pj4gUmVxdWVzdCBJUlEgd2l0aCBJUlFGX1NIQVJFRCBmbGFnLiBUaGlzIHdv cmtzIHNpbmNlIHRoZSBpbnRlcnJ1cHQKPiA+Pj4+PiBoYW5kbGVyIGFscmVhZHkgY2hlY2tzIGlm IHRoZXJlIGlzIGFuIGFjdHVhbCBJUlEgcGVuZGluZyBhbmQgcmV0dXJucwo+ID4+Pj4+IElSUV9O T05FIG90aGVyd2lzZS4KPiA+Pj4+Cj4gPj4+PiBobW1tIHdoYXQgYXJlIHdlIHRyeWluZyB0byBm aXggaGVyZT8gSXMgeW91ciBkZXZpY2Ugb24gYSBzaGFyZWQgbGluZSBvciBub3Q/Cj4gPj4+Cj4g Pj4+IElSUUZfU0hBUkVEIGRvZXMgbm90IG1lYW4gdGhhdCB0aGUgSVJRIGlzIG9uIGEgc2hhcmVk IGxpbmUuIEl0IG1lYW5zIHRoYXQKPiA+Pj4gdGhlIGRyaXZlciBjYW4gaGFuZGxlIGl0IGlmIHRo ZSBJUlEgaXMgb24gYSBzaGFyZWQgbGluZS4gU2luY2UgdGhlIGRyaXZlcgo+ID4+PiBjYW4gaGFu ZGxlIGl0IHNldHRpbmcgdGhlIGZsYWcgaXMgYSBnb29kIGlkZWEgc2luY2UgdGhpcyBlbmFibGVz IHVzZWNhc2VzCj4gPj4+IHdoZXJlIHRoZSBsaW5lIGlzIHNoYXJlZC4KPiA+Pgo+ID4+IFllcyB0 aGF0IGlzIGNvcnJlY3QgaW5kZWVkLCBidXQgd2hhdCBpcyB0aGUgbW90aXZhdGlvbiBmb3IgdGhl IGNoYW5nZS4KPiA+Pgo+ID4+IElmIHlvdSBuZXZlciBleHBlY3QgdGhpcyB0byBiZSBpbiBzaGFy ZWQgZW52aXJvbm1lbnQgd2h5IHRvIGRvIHRoaXM/Cj4gPj4gU29ycnkgYnV0ICJpdCB3b3JrcyIg aXMgbm90IGEgZ29vZCBlbm91Z2ggcmVhc29uIGZvciB0aGlzIGNoYW5nZSwgdG8gZW5hYmxlCj4g Pj4gdXNlY2FzZXMgd2hlcmUgdGhlIGxpbmUgaXMgc2hhcmVkIGlzIGEgZ29vZCByZWFzb24gOikK PiA+IAo+ID4gUmVtZW1iZXIsIHRoaXMgaXMgYW4gRlBHQSBzb2Z0IGNvcmUuIEkgaGFwcGVuIHRv IGhhdmUgYSBkZXNpZ24gWzFdIHdoZXJlIGl0Cj4gPiBpcyBob29rZWQgdXAgd2l0aCBtdWx0aXBs ZSBvZiB0aGVtIG9uIG9uZSBJUlEgbGluZSwgc28gdG8gbWFrZSB0aGlzIHdvcmssCj4gPiBJIG5l ZWQgdGhpcyBjaGFuZ2UuCj4gCj4gSSB0aGluayB3aGF0IFZpbm9kIGlzIGFza2luZyBmb3IgaXMg YSBjaGFuZ2UgdG8gdGhlIGNvbW1pdCBtZXNzYWdlIHNheWluZwo+IHRoYXQgInRoaXMgY2hhbmdl IGVuYWJsZXMgdGhlIGRyaXZlciB0byBiZSB1c2VkIHdpdGggZGV2aWNlcyB3aGVyZSB0aGUKPiBp bnRlcnJ1cHQgbGluZSBpcyBzaGFyZWQiLgoKQ29ycmVjdCwgY2hhbmdlbG9nIG5lZWQgdG8gcmVm bGVjdCB3aHkgYSBjaGFuZ2Ugd2FzIG1hZGUsIGRvd24gdGhlIGxpbmUKcGVvcGxlIG5lZWQgdG8g a25vdyB0aGUgcmVhc29ucywgc29tZXRpbWVzIGl0IG1pZ2h0IGJlIGV2ZW4geW91Li4K From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752663AbeD1FGD (ORCPT ); Sat, 28 Apr 2018 01:06:03 -0400 Received: from mga03.intel.com ([134.134.136.65]:62283 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751342AbeD1FGB (ORCPT ); Sat, 28 Apr 2018 01:06:01 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,337,1520924400"; d="scan'208";a="35277339" Date: Sat, 28 Apr 2018 10:40:43 +0530 From: Vinod Koul To: Lars-Peter Clausen Cc: Moritz Fischer , Linux Kernel Mailing List , dmaengine@vger.kernel.org, dan.j.williams@intel.com Subject: Re: [PATCH v2] dmaengine: axi-dmac: Request IRQ with IRQF_SHARED Message-ID: <20180428051043.GG6014@localhost> References: <20180426174000.12008-1-mdf@kernel.org> <20180427051115.GX6014@localhost> <748ffc14-de12-c11e-eb12-65c599fe5f4e@metafoo.de> <20180427070830.GC6014@localhost> <716956a2-a4f4-9cbd-8761-8db477f1dfc0@metafoo.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <716956a2-a4f4-9cbd-8761-8db477f1dfc0@metafoo.de> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 27, 2018 at 05:18:29PM +0200, Lars-Peter Clausen wrote: > On 04/27/2018 05:15 PM, Moritz Fischer wrote: > > Hi Vinod, > > > > On Fri, Apr 27, 2018 at 12:08 AM, Vinod Koul wrote: > >> On Fri, Apr 27, 2018 at 08:53:39AM +0200, Lars-Peter Clausen wrote: > >>> On 04/27/2018 07:11 AM, Vinod Koul wrote: > >>>> On Thu, Apr 26, 2018 at 10:40:00AM -0700, Moritz Fischer wrote: > >>>>> Request IRQ with IRQF_SHARED flag. This works since the interrupt > >>>>> handler already checks if there is an actual IRQ pending and returns > >>>>> IRQ_NONE otherwise. > >>>> > >>>> hmmm what are we trying to fix here? Is your device on a shared line or not? > >>> > >>> IRQF_SHARED does not mean that the IRQ is on a shared line. It means that > >>> the driver can handle it if the IRQ is on a shared line. Since the driver > >>> can handle it setting the flag is a good idea since this enables usecases > >>> where the line is shared. > >> > >> Yes that is correct indeed, but what is the motivation for the change. > >> > >> If you never expect this to be in shared environment why to do this? > >> Sorry but "it works" is not a good enough reason for this change, to enable > >> usecases where the line is shared is a good reason :) > > > > Remember, this is an FPGA soft core. I happen to have a design [1] where it > > is hooked up with multiple of them on one IRQ line, so to make this work, > > I need this change. > > I think what Vinod is asking for is a change to the commit message saying > that "this change enables the driver to be used with devices where the > interrupt line is shared". Correct, changelog need to reflect why a change was made, down the line people need to know the reasons, sometimes it might be even you.. -- ~Vinod