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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 32689C48BD1 for ; Thu, 10 Jun 2021 10:00:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1903461359 for ; Thu, 10 Jun 2021 10:00:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229941AbhFJKCg (ORCPT ); Thu, 10 Jun 2021 06:02:36 -0400 Received: from mx08-00178001.pphosted.com ([91.207.212.93]:39804 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S229770AbhFJKCf (ORCPT ); Thu, 10 Jun 2021 06:02:35 -0400 Received: from pps.filterd (m0046661.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 15A9vwfY026066; Thu, 10 Jun 2021 12:00:28 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foss.st.com; h=from : to : cc : subject : date : message-id : mime-version : content-type; s=selector1; bh=CkJNWXGmOEbJPEOGF2dk0bMdnvuwJI+M4NFLzCdau3Q=; b=dqaOpPxe3iRRC6frrImuYQ61nDtbPhjxQO8NfLGxX2s4iZMrgqTQCIjTRWBp8n95dSs6 yn1VD/tFo1dUR2yC4MqznTnAfdoNd9RyAP3LY6aWmi+Lnxnk8vbommBn2Ix5zJm07h4m +I+Er9E8JeQZHYgn5USUubzZGxroItSJzahq4NqBb6JQfKIFLEBJYbFCySdb5xh7LhWu bmrOBDwCYSib78Ryl19PbYTkcmHTKSfNU4TfvtdENkQ8fVIIyIQq1s6L1/QsOCYE/im8 rqJ9GHRNGO+Uo/ZDYXfuo2TaNQHTMrxEJ6xxfcs7xYneevLYe5nqB6/4IZwNbX64C10Q 6g== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 39350hbs5x-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 10 Jun 2021 12:00:28 +0200 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 3B20A10002A; Thu, 10 Jun 2021 12:00:27 +0200 (CEST) Received: from Webmail-eu.st.com (sfhdag2node3.st.com [10.75.127.6]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 1D50421CA7B; Thu, 10 Jun 2021 12:00:27 +0200 (CEST) Received: from localhost (10.75.127.46) by SFHDAG2NODE3.st.com (10.75.127.6) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 10 Jun 2021 12:00:26 +0200 From: Erwan Le Ray To: Greg Kroah-Hartman , Jiri Slaby , Maxime Coquelin , Alexandre Torgue CC: , , , , Erwan Le Ray , Fabrice Gasnier , Valentin Caron , Amelie Delaunay , Etienne Carriere Subject: [PATCH 1/1] serial: stm32: defer probe for dma devices Date: Thu, 10 Jun 2021 12:00:20 +0200 Message-ID: <20210610100020.2318-1-erwan.leray@foss.st.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.75.127.46] X-ClientProxiedBy: SFHDAG1NODE3.st.com (10.75.127.3) To SFHDAG2NODE3.st.com (10.75.127.6) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-06-10_05:2021-06-10,2021-06-10 signatures=0 Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org Defer device probe operation when a DMA channel request probe deferral. With this change both DMA channels are acquired before DMA channels are configured. Once no probe deferral is expected, DMAs are configured and any failure in their configuration will make the driver to fallback to interrupt mode as prior this change. Signed-off-by: Erwan Le Ray Signed-off-by: Etienne Carriere diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index bf188bdf9717..cd6adb979df9 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -1182,6 +1182,14 @@ static const struct of_device_id stm32_match[] = { MODULE_DEVICE_TABLE(of, stm32_match); #endif +static void stm32_usart_of_dma_rx_remove(struct stm32_port *stm32port, + struct platform_device *pdev) +{ + if (stm32port->rx_buf) + dma_free_coherent(&pdev->dev, RX_BUF_L, stm32port->rx_buf, + stm32port->rx_dma_buf); +} + static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port, struct platform_device *pdev) { @@ -1199,19 +1207,11 @@ static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port, if (uart_console(port)) return -ENODEV; - /* Request DMA RX channel */ - stm32port->rx_ch = dma_request_slave_channel(dev, "rx"); - if (!stm32port->rx_ch) { - dev_info(dev, "rx dma alloc failed\n"); - return -ENODEV; - } stm32port->rx_buf = dma_alloc_coherent(&pdev->dev, RX_BUF_L, &stm32port->rx_dma_buf, GFP_KERNEL); - if (!stm32port->rx_buf) { - ret = -ENOMEM; - goto alloc_err; - } + if (!stm32port->rx_buf) + return -ENOMEM; /* Configure DMA channel */ memset(&config, 0, sizeof(config)); @@ -1221,8 +1221,8 @@ static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port, ret = dmaengine_slave_config(stm32port->rx_ch, &config); if (ret < 0) { dev_err(dev, "rx dma channel config failed\n"); - ret = -ENODEV; - goto config_err; + stm32_usart_of_dma_rx_remove(stm32port, pdev); + return ret; } /* Prepare a DMA cyclic transaction */ @@ -1232,8 +1232,8 @@ static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port, DMA_PREP_INTERRUPT); if (!desc) { dev_err(dev, "rx dma prep cyclic failed\n"); - ret = -ENODEV; - goto config_err; + stm32_usart_of_dma_rx_remove(stm32port, pdev); + return -ENODEV; } /* No callback as dma buffer is drained on usart interrupt */ @@ -1244,24 +1244,22 @@ static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port, ret = dma_submit_error(dmaengine_submit(desc)); if (ret) { dmaengine_terminate_sync(stm32port->rx_ch); - goto config_err; + stm32_usart_of_dma_rx_remove(stm32port, pdev); + return ret; } /* Issue pending DMA requests */ dma_async_issue_pending(stm32port->rx_ch); return 0; +} -config_err: - dma_free_coherent(&pdev->dev, - RX_BUF_L, stm32port->rx_buf, - stm32port->rx_dma_buf); - -alloc_err: - dma_release_channel(stm32port->rx_ch); - stm32port->rx_ch = NULL; - - return ret; +static void stm32_usart_of_dma_tx_remove(struct stm32_port *stm32port, + struct platform_device *pdev) +{ + if (stm32port->tx_buf) + dma_free_coherent(&pdev->dev, TX_BUF_L, stm32port->tx_buf, + stm32port->tx_dma_buf); } static int stm32_usart_of_dma_tx_probe(struct stm32_port *stm32port, @@ -1275,19 +1273,11 @@ static int stm32_usart_of_dma_tx_probe(struct stm32_port *stm32port, stm32port->tx_dma_busy = false; - /* Request DMA TX channel */ - stm32port->tx_ch = dma_request_slave_channel(dev, "tx"); - if (!stm32port->tx_ch) { - dev_info(dev, "tx dma alloc failed\n"); - return -ENODEV; - } stm32port->tx_buf = dma_alloc_coherent(&pdev->dev, TX_BUF_L, &stm32port->tx_dma_buf, GFP_KERNEL); - if (!stm32port->tx_buf) { - ret = -ENOMEM; - goto alloc_err; - } + if (!stm32port->tx_buf) + return -ENOMEM; /* Configure DMA channel */ memset(&config, 0, sizeof(config)); @@ -1297,22 +1287,11 @@ static int stm32_usart_of_dma_tx_probe(struct stm32_port *stm32port, ret = dmaengine_slave_config(stm32port->tx_ch, &config); if (ret < 0) { dev_err(dev, "tx dma channel config failed\n"); - ret = -ENODEV; - goto config_err; + stm32_usart_of_dma_tx_remove(stm32port, pdev); + return ret; } return 0; - -config_err: - dma_free_coherent(&pdev->dev, - TX_BUF_L, stm32port->tx_buf, - stm32port->tx_dma_buf); - -alloc_err: - dma_release_channel(stm32port->tx_ch); - stm32port->tx_ch = NULL; - - return ret; } static int stm32_usart_serial_probe(struct platform_device *pdev) @@ -1336,16 +1315,43 @@ static int stm32_usart_serial_probe(struct platform_device *pdev) device_set_wakeup_capable(&pdev->dev, true); ret = dev_pm_set_wake_irq(&pdev->dev, stm32port->port.irq); if (ret) - goto err_nowup; + goto err_deinit_port; } - ret = stm32_usart_of_dma_rx_probe(stm32port, pdev); - if (ret) - dev_info(&pdev->dev, "interrupt mode used for rx (no dma)\n"); + stm32port->rx_ch = dma_request_chan(&pdev->dev, "rx"); + if (PTR_ERR(stm32port->rx_ch) == -EPROBE_DEFER) { + ret = -EPROBE_DEFER; + goto err_wakeirq; + } + /* Fall back in interrupt mode for any non-deferral error */ + if (IS_ERR(stm32port->rx_ch)) + stm32port->rx_ch = NULL; + + stm32port->tx_ch = dma_request_chan(&pdev->dev, "tx"); + if (PTR_ERR(stm32port->tx_ch) == -EPROBE_DEFER) { + ret = -EPROBE_DEFER; + goto err_dma_rx; + } + /* Fall back in interrupt mode for any non-deferral error */ + if (IS_ERR(stm32port->tx_ch)) + stm32port->tx_ch = NULL; - ret = stm32_usart_of_dma_tx_probe(stm32port, pdev); - if (ret) - dev_info(&pdev->dev, "interrupt mode used for tx (no dma)\n"); + if (stm32port->rx_ch && stm32_usart_of_dma_rx_probe(stm32port, pdev)) { + /* Fall back in interrupt mode */ + dma_release_channel(stm32port->rx_ch); + stm32port->rx_ch = NULL; + } + + if (stm32port->tx_ch && stm32_usart_of_dma_tx_probe(stm32port, pdev)) { + /* Fall back in interrupt mode */ + dma_release_channel(stm32port->tx_ch); + stm32port->tx_ch = NULL; + } + + if (!stm32port->rx_ch) + dev_info(&pdev->dev, "interrupt mode for rx (no dma)\n"); + if (!stm32port->tx_ch) + dev_info(&pdev->dev, "interrupt mode for tx (no dma)\n"); platform_set_drvdata(pdev, &stm32port->port); @@ -1366,30 +1372,23 @@ static int stm32_usart_serial_probe(struct platform_device *pdev) pm_runtime_set_suspended(&pdev->dev); pm_runtime_put_noidle(&pdev->dev); - if (stm32port->rx_ch) { - dmaengine_terminate_async(stm32port->rx_ch); - dma_release_channel(stm32port->rx_ch); - } - - if (stm32port->rx_dma_buf) - dma_free_coherent(&pdev->dev, - RX_BUF_L, stm32port->rx_buf, - stm32port->rx_dma_buf); - if (stm32port->tx_ch) { - dmaengine_terminate_async(stm32port->tx_ch); + stm32_usart_of_dma_tx_remove(stm32port, pdev); dma_release_channel(stm32port->tx_ch); } - if (stm32port->tx_dma_buf) - dma_free_coherent(&pdev->dev, - TX_BUF_L, stm32port->tx_buf, - stm32port->tx_dma_buf); + if (stm32port->rx_ch) + stm32_usart_of_dma_rx_remove(stm32port, pdev); +err_dma_rx: + if (stm32port->rx_ch) + dma_release_channel(stm32port->rx_ch); + +err_wakeirq: if (stm32port->wakeup_src) dev_pm_clear_wake_irq(&pdev->dev); -err_nowup: +err_deinit_port: if (stm32port->wakeup_src) device_set_wakeup_capable(&pdev->dev, false); @@ -1416,28 +1415,20 @@ static int stm32_usart_serial_remove(struct platform_device *pdev) stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAR); + if (stm32_port->tx_ch) { + dmaengine_terminate_async(stm32_port->tx_ch); + stm32_usart_of_dma_tx_remove(stm32_port, pdev); + dma_release_channel(stm32_port->tx_ch); + } + if (stm32_port->rx_ch) { dmaengine_terminate_async(stm32_port->rx_ch); + stm32_usart_of_dma_rx_remove(stm32_port, pdev); dma_release_channel(stm32_port->rx_ch); } - if (stm32_port->rx_dma_buf) - dma_free_coherent(&pdev->dev, - RX_BUF_L, stm32_port->rx_buf, - stm32_port->rx_dma_buf); - stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT); - if (stm32_port->tx_ch) { - dmaengine_terminate_async(stm32_port->tx_ch); - dma_release_channel(stm32_port->tx_ch); - } - - if (stm32_port->tx_dma_buf) - dma_free_coherent(&pdev->dev, - TX_BUF_L, stm32_port->tx_buf, - stm32_port->tx_dma_buf); - if (stm32_port->wakeup_src) { dev_pm_clear_wake_irq(&pdev->dev); device_init_wakeup(&pdev->dev, false); -- 2.17.1