From patchwork Wed Jan 29 15:36:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Amelie Delaunay X-Patchwork-Id: 11356395 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2C23E188B for ; Wed, 29 Jan 2020 15:37:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 019C320732 for ; Wed, 29 Jan 2020 15:37:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=st.com header.i=@st.com header.b="VKAuCipx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727103AbgA2PhT (ORCPT ); Wed, 29 Jan 2020 10:37:19 -0500 Received: from mx08-00178001.pphosted.com ([91.207.212.93]:20768 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726742AbgA2Pgy (ORCPT ); Wed, 29 Jan 2020 10:36:54 -0500 Received: from pps.filterd (m0046660.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 00TFNdPW030994; Wed, 29 Jan 2020 16:36:39 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=st.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=STMicroelectronics; bh=fNTUXAf+YlisbazBqB3yomSG66KZ61nDeHHXPvZUmB0=; b=VKAuCipx3bFKSSGXXWVDJuLxcNNSl9Rfa+ZSyFdvEi9ZoEJLKa8rngoQLq6VCq431w4E TZ9uOx5nx5W6+sISmZZO9zR57ATVy0M6hnJZHnv0gUMsKhyLLuJmKmeiEIVzc9gl50Ie sXX6TYJYeTkwlDfiWcW6Sqj6Q4O2xTJKkqg0qOh/SQcxyiQ1zHPLPL7I6BUbdNkN4KJs OoIGQk7aCVRpH985TybpinzkFXcuCAOwwSgiSI45iUWRa20unJoVu0Wc6lOggXjpRAo2 sfxnxjcUcAgFMS6tEEsKH+PD4AcY1yjrTk7DjxVZW7iErP64/9bYPRBPjLOB2Q5DCJ/P nQ== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 2xrbpb45ee-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 29 Jan 2020 16:36:39 +0100 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id E2FE7100039; Wed, 29 Jan 2020 16:36:38 +0100 (CET) Received: from Webmail-eu.st.com (sfhdag3node2.st.com [10.75.127.8]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id D1E002BC7C2; Wed, 29 Jan 2020 16:36:38 +0100 (CET) Received: from localhost (10.75.127.46) by SFHDAG3NODE2.st.com (10.75.127.8) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Wed, 29 Jan 2020 16:36:38 +0100 From: Amelie Delaunay To: Vinod Koul , Dan Williams , Maxime Coquelin , Alexandre Torgue CC: , , , , Amelie Delaunay , Pierre-Yves MORDRET Subject: [PATCH 7/8] dmaengine: stm32-dma: fix sleeping function called from invalid context Date: Wed, 29 Jan 2020 16:36:27 +0100 Message-ID: <20200129153628.29329-8-amelie.delaunay@st.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200129153628.29329-1-amelie.delaunay@st.com> References: <20200129153628.29329-1-amelie.delaunay@st.com> MIME-Version: 1.0 X-Originating-IP: [10.75.127.46] X-ClientProxiedBy: SFHDAG8NODE2.st.com (10.75.127.23) To SFHDAG3NODE2.st.com (10.75.127.8) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.572 definitions=2020-01-29_03:2020-01-28,2020-01-29 signatures=0 Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org This patch fixes BUG: sleeping function called from invalid context in stm32_dma_disable_chan function. The goal of this function is to force channel disable if it has not been disabled by hardware. This consists in clearing STM32_DMA_SCR_EN bit and read it as 0 to ensure the channel is well disabled and the last transfer is over. In previous implementation, the waiting loop was based on a do...while (1) with a call to cond_resched to give the scheduler a chance to run a higher priority process. But in some conditions, stm32_dma_disable_chan can be called while preemption is disabled, on a stm32_dma_stop call for example. So cond_resched must not be used. To avoid this, use readl_relaxed_poll_timeout_atomic to poll STM32_DMA_SCR_EN bit cleared. Signed-off-by: Amelie Delaunay --- drivers/dma/stm32-dma.c | 27 +++++++++------------------ 1 file changed, 9 insertions(+), 18 deletions(-) diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c index 01a2374ae03a..b585e11c2168 100644 --- a/drivers/dma/stm32-dma.c +++ b/drivers/dma/stm32-dma.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include @@ -421,29 +422,19 @@ static void stm32_dma_irq_clear(struct stm32_dma_chan *chan, u32 flags) static int stm32_dma_disable_chan(struct stm32_dma_chan *chan) { struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan); - unsigned long timeout = jiffies + msecs_to_jiffies(5000); - u32 dma_scr, id; + u32 dma_scr, id, reg; id = chan->id; - dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id)); + reg = STM32_DMA_SCR(id); + dma_scr = stm32_dma_read(dmadev, reg); if (dma_scr & STM32_DMA_SCR_EN) { dma_scr &= ~STM32_DMA_SCR_EN; - stm32_dma_write(dmadev, STM32_DMA_SCR(id), dma_scr); - - do { - dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id)); - dma_scr &= STM32_DMA_SCR_EN; - if (!dma_scr) - break; - - if (time_after_eq(jiffies, timeout)) { - dev_err(chan2dev(chan), "%s: timeout!\n", - __func__); - return -EBUSY; - } - cond_resched(); - } while (1); + stm32_dma_write(dmadev, reg, dma_scr); + + return readl_relaxed_poll_timeout_atomic(dmadev->base + reg, + dma_scr, !(dma_scr & STM32_DMA_SCR_EN), + 10, 1000000); } return 0;