From patchwork Mon Oct 11 14:36:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Cercueil X-Patchwork-Id: 12550183 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB473C433EF for ; Mon, 11 Oct 2021 14:39:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 98A32603E9 for ; Mon, 11 Oct 2021 14:39:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244390AbhJKOlD (ORCPT ); Mon, 11 Oct 2021 10:41:03 -0400 Received: from aposti.net ([89.234.176.197]:46660 "EHLO aposti.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243614AbhJKOjx (ORCPT ); Mon, 11 Oct 2021 10:39:53 -0400 From: Paul Cercueil To: Vinod Koul , Rob Herring Cc: list@opendingux.net, dmaengine@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, Paul Cercueil Subject: [PATCH 3/5] dmaengine: jz4780: Work around hardware bug on JZ4760 SoCs Date: Mon, 11 Oct 2021 16:36:50 +0200 Message-Id: <20211011143652.51976-4-paul@crapouillou.net> In-Reply-To: <20211011143652.51976-1-paul@crapouillou.net> References: <20211011143652.51976-1-paul@crapouillou.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org The JZ4760 SoC has a hardware problem with chan0 not enabling properly if it's enabled before chan1, after a reset (works fine afterwards). This is worked around in the probe function by just enabling then disabling chan1. Signed-off-by: Paul Cercueil --- drivers/dma/dma-jz4780.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/dma/dma-jz4780.c b/drivers/dma/dma-jz4780.c index ebee94dbd630..d71bc7235959 100644 --- a/drivers/dma/dma-jz4780.c +++ b/drivers/dma/dma-jz4780.c @@ -937,6 +937,14 @@ static int jz4780_dma_probe(struct platform_device *pdev) jzchan->vchan.desc_free = jz4780_dma_desc_free; } + /* + * On JZ4760, chan0 won't enable properly the first time. + * Enabling then disabling chan1 will magically make chan0 work + * correctly. + */ + jz4780_dma_chan_enable(jzdma, 1); + jz4780_dma_chan_disable(jzdma, 1); + ret = platform_get_irq(pdev, 0); if (ret < 0) goto err_disable_clk;