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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 5F497C4151A for ; Sun, 17 Feb 2019 10:59:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 371F62173C for ; Sun, 17 Feb 2019 10:59:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728451AbfBQK67 (ORCPT ); Sun, 17 Feb 2019 05:58:59 -0500 Received: from www1102.sakura.ne.jp ([219.94.129.142]:21978 "EHLO www1102.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726003AbfBQK67 (ORCPT ); Sun, 17 Feb 2019 05:58:59 -0500 Received: from fsav103.sakura.ne.jp (fsav103.sakura.ne.jp [27.133.134.230]) by www1102.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id x1HAwakg030582; Sun, 17 Feb 2019 19:58:37 +0900 (JST) (envelope-from katsuhiro@katsuster.net) Received: from www1102.sakura.ne.jp (219.94.129.142) by fsav103.sakura.ne.jp (F-Secure/fsigk_smtp/530/fsav103.sakura.ne.jp); Sun, 17 Feb 2019 19:58:36 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/530/fsav103.sakura.ne.jp) Received: from [192.168.1.2] (119.104.232.153.ap.dti.ne.jp [153.232.104.119]) (authenticated bits=0) by www1102.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id x1HAwaEH030577 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NO); Sun, 17 Feb 2019 19:58:36 +0900 (JST) (envelope-from katsuhiro@katsuster.net) Subject: Re: [PATCH] arm64: dts: rockchip: add HDMI sound node for rk3328-rock64 To: =?UTF-8?Q?Heiko_St=c3=bcbner?= Cc: linux-rockchip@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20190202043444.9308-1-katsuhiro@katsuster.net> <1970132.3b67tCGWFf@phil> <2275914.n7pQDzs7mT@diego> From: Katsuhiro Suzuki Message-ID: <16f4fcf0-e9c2-e925-e463-282cfff088c7@katsuster.net> Date: Sun, 17 Feb 2019 19:58:36 +0900 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.0 MIME-Version: 1.0 In-Reply-To: <2275914.n7pQDzs7mT@diego> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Heiko, On 2019/02/12 20:12, Heiko Stübner wrote: > Hi, > > Am Montag, 4. Februar 2019, 13:59:37 CET schrieb Katsuhiro Suzuki: >> On 2019/02/03 18:06, Heiko Stuebner wrote: >>> Am Samstag, 2. Februar 2019, 05:34:44 CET schrieb Katsuhiro Suzuki: >>>> This patch adds HDMI sound (I2S0) node and remove dma properties >>>> from UART2 node for rock64. >>>> >>>> The DMAC of rk3328 can use 8 channels at same time. Currently, total >>>> >>>> 7 channels are used as follows: >>>> - I2S1 2ch >>>> - UART2 2ch >>>> - SPDIF 1ch >>>> - SPI0 2ch >>>> >>>> HDMI audio using I2S0 that requires 2ch but DMAC has only 1 channel. >>>> >>>> UART2 can work without DMA resources, so this patch removes dma >>>> allocation for UART2 and reuses it to I2S0. >>> >>> I don't follow that description. How can i2s0 re-use the uart2 dma >>> channels? Looking at the dma table in the TRM, uart2 has channels 6+7 >>> while i2s0 uses channels 11+12. They should just run concurrently? >> >> Sorry for confusing... 6 or 7 is as ID number of slave DMA channel. >> TRM calls it 'Req number'. Req number 6+7 and 11+12 can work >> concurrently but TRM says DMAC can transfer 8 DMA channels at same >> time. So all 16 Req numbers cannot activate at same time. It should >> be keep less or equal than 8 numbers. > > But that "shortcoming" of having more requests than channels is not > something specific to the pl330, instead most dma controllers have that > "problem", which seems to get solved by the virt-dma mechanism of > dmaengine - which pl330 doesn't use so far. (but see pl080 for example) > I understand. I drop these patches. > The devicetree only describes the hardware and is never meant as a > configuration space for kernel-code shortcomings. > Yes, right. I don't want to use device-tree as configuration space, so which is better? - Fix the pl330 driver first and after that add HDMI-sound node to device-tree. - Just add HDMI-sound node to device-tree. If someone (include me) want to support virt-dma on pl330 driver, they will fix it. (PL330 will face error but all sounds works fine and UART still works fine with DMA error) > > Heiko > > > Best Regards, Katsuhiro Suzuki