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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 B896BC433DF for ; Tue, 9 Jun 2020 00:10:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 76E5A2078D for ; Tue, 9 Jun 2020 00:10:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591661458; bh=ZraaEuuPkmmE6JaAbmpXV8KJ8l2d6seauiZRtyAVBWU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=KgeTYaG6bjAkz/1nBhCNK0ExujDjnTHUitxh2A0sEx9on3sHqHFZI2VR4l7amKCyv G/dUsQascJtfO3K03IL47u0qszwTFE0Fvp/S/RSwS2ZiMRXi3xoQjud6P/YFofQeyO 0gs/UuW1e4d68dat2FBOckuVwrJX7+baM8cI8XP0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732867AbgFIAK5 (ORCPT ); Mon, 8 Jun 2020 20:10:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:43248 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730899AbgFHXUC (ORCPT ); Mon, 8 Jun 2020 19:20:02 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D924420814; Mon, 8 Jun 2020 23:19:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591658401; bh=ZraaEuuPkmmE6JaAbmpXV8KJ8l2d6seauiZRtyAVBWU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=A7c0pyF8MtJbDvfE7eW63PyzC2mV03AEfBw54cON5w85WSvkfHsVj4/hYlJZq9xTj 9UWENDtNxsfukm5TeQmPN+svOlLpRCTJdvvsVJ5mpyoCvsIQAZErw35c5Bc2vr2cOk Fh/8jhzrvZXI6gwQWhiRxO/D6ernjlT3GUD6s0Ss= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Serge Semin , Andy Shevchenko , Georgy Vlasov , Ramil Zaripov , Alexey Malahov , Thomas Bogendoerfer , Arnd Bergmann , Feng Tang , Rob Herring , linux-mips@vger.kernel.org, devicetree@vger.kernel.org, Mark Brown , Sasha Levin , linux-spi@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 056/175] spi: dw: Fix Rx-only DMA transfers Date: Mon, 8 Jun 2020 19:16:49 -0400 Message-Id: <20200608231848.3366970-56-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200608231848.3366970-1-sashal@kernel.org> References: <20200608231848.3366970-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Serge Semin [ Upstream commit 46164fde6b7890e7a3982d54549947c8394c0192 ] Tx-only DMA transfers are working perfectly fine since in this case the code just ignores the Rx FIFO overflow interrupts. But it turns out the SPI Rx-only transfers are broken since nothing pushing any data to the shift registers, so the Rx FIFO is left empty and the SPI core subsystems just returns a timeout error. Since DW DMAC driver doesn't support something like cyclic write operations of a single byte to a device register, the only way to support the Rx-only SPI transfers is to fake it by using a dummy Tx-buffer. This is what we intend to fix in this commit by setting the SPI_CONTROLLER_MUST_TX flag for DMA-capable platform. Signed-off-by: Serge Semin Reviewed-by: Andy Shevchenko Cc: Georgy Vlasov Cc: Ramil Zaripov Cc: Alexey Malahov Cc: Thomas Bogendoerfer Cc: Arnd Bergmann Cc: Feng Tang Cc: Rob Herring Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200529131205.31838-9-Sergey.Semin@baikalelectronics.ru Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- drivers/spi/spi-dw.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c index 11cac7e10663..8a4438f4c954 100644 --- a/drivers/spi/spi-dw.c +++ b/drivers/spi/spi-dw.c @@ -518,6 +518,7 @@ int dw_spi_add_host(struct device *dev, struct dw_spi *dws) dws->dma_inited = 0; } else { master->can_dma = dws->dma_ops->can_dma; + master->flags |= SPI_CONTROLLER_MUST_TX; } } -- 2.25.1