From patchwork Fri Sep 14 17:06:14 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lucas Stach X-Patchwork-Id: 10601111 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 521FD14DB for ; Fri, 14 Sep 2018 17:06:19 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 38A5B2BA85 for ; Fri, 14 Sep 2018 17:06:19 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2CFD72BB37; Fri, 14 Sep 2018 17:06:19 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 81FC52BB27 for ; Fri, 14 Sep 2018 17:06:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726891AbeINWVj (ORCPT ); Fri, 14 Sep 2018 18:21:39 -0400 Received: from metis.ext.pengutronix.de ([85.220.165.71]:40343 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726969AbeINWVi (ORCPT ); Fri, 14 Sep 2018 18:21:38 -0400 Received: from dude.hi.pengutronix.de ([2001:67c:670:100:1d::7] helo=dude.pengutronix.de.) by metis.ext.pengutronix.de with esmtp (Exim 4.89) (envelope-from ) id 1g0rXr-0000yl-Js; Fri, 14 Sep 2018 19:06:15 +0200 From: Lucas Stach To: Vinod Koul Cc: dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, Robin Gong , linux-imx@nxp.com, kernel@pengutronix.de, patchwork-lst@pengutronix.de Subject: [PATCH v2 3/4] dmaengine: imx-sdma: implement channel termination via worker Date: Fri, 14 Sep 2018 19:06:14 +0200 Message-Id: <20180914170615.12659-3-l.stach@pengutronix.de> X-Mailer: git-send-email 2.19.0 In-Reply-To: <20180914170615.12659-1-l.stach@pengutronix.de> References: <20180914170615.12659-1-l.stach@pengutronix.de> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::7 X-SA-Exim-Mail-From: l.stach@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: dmaengine@vger.kernel.org Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The dmaengine documentation states that device_terminate_all may be asynchronous and need not wait for the active transfers have stopped. This allows us to move most of the functionality currently implemented in the sdma channel termination function to run in a worker, outside of any atomic context. Moving this out of atomic context has two benefits: we can now sleep while waiting for the channel to terminate, instead of busy waiting and the freeing of the dma descriptors happens with IRQs enabled, getting rid of a warning in the dma mapping code. As the termination is now asnc, we need to implement the device_synchronize dma engine function, which simply waits for the worker to finish its execution. Signed-off-by: Lucas Stach --- v2: Keep vchan_get_all_descriptors in the terminate_all call, so the worker doesn't corrupt the next transfer if that's already in the setup process. --- drivers/dma/imx-sdma.c | 42 ++++++++++++++++++++++++++++++++---------- 1 file changed, 32 insertions(+), 10 deletions(-) diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c index 8d2fec8b16cc..da41e8fbf151 100644 --- a/drivers/dma/imx-sdma.c +++ b/drivers/dma/imx-sdma.c @@ -32,6 +32,7 @@ #include #include #include +#include #include #include @@ -375,6 +376,8 @@ struct sdma_channel { u32 shp_addr, per_addr; enum dma_status status; struct imx_dma_data data; + struct work_struct terminate_worker; + struct list_head deferred_desc_list; }; #define IMX_DMA_SG_LOOP BIT(0) @@ -1025,31 +1028,47 @@ static int sdma_disable_channel(struct dma_chan *chan) return 0; } +static void sdma_channel_terminate(struct work_struct *work) +{ + struct sdma_channel *sdmac = container_of(work, struct sdma_channel, + terminate_worker); + + /* + * According to NXP R&D team a delay of one BD SDMA cost time + * (maximum is 1ms) should be added after disable of the channel + * bit, to ensure SDMA core has really been stopped after SDMA + * clients call .device_terminate_all. + */ + usleep_range(1000, 2000); + + vchan_dma_desc_free_list(&sdmac->vc, &sdmac->deferred_desc_list); + INIT_LIST_HEAD(&sdmac->deferred_desc_list); +} static int sdma_disable_channel_with_delay(struct dma_chan *chan) { struct sdma_channel *sdmac = to_sdma_chan(chan); unsigned long flags; - LIST_HEAD(head); sdma_disable_channel(chan); + spin_lock_irqsave(&sdmac->vc.lock, flags); - vchan_get_all_descriptors(&sdmac->vc, &head); + vchan_get_all_descriptors(&sdmac->vc, &sdmac->deferred_desc_list); sdmac->desc = NULL; spin_unlock_irqrestore(&sdmac->vc.lock, flags); - vchan_dma_desc_free_list(&sdmac->vc, &head); - /* - * According to NXP R&D team a delay of one BD SDMA cost time - * (maximum is 1ms) should be added after disable of the channel - * bit, to ensure SDMA core has really been stopped after SDMA - * clients call .device_terminate_all. - */ - mdelay(1); + schedule_work(&sdmac->terminate_worker); return 0; } +static void sdma_channel_synchronize(struct dma_chan *chan) +{ + struct sdma_channel *sdmac = to_sdma_chan(chan); + + flush_work(&sdmac->terminate_worker); +} + static void sdma_set_watermarklevel_for_p2p(struct sdma_channel *sdmac) { struct sdma_engine *sdma = sdmac->sdma; @@ -1993,6 +2012,8 @@ static int sdma_probe(struct platform_device *pdev) sdmac->channel = i; sdmac->vc.desc_free = sdma_desc_free; + INIT_WORK(&sdmac->terminate_worker, sdma_channel_terminate); + INIT_LIST_HEAD(&sdmac->deferred_desc_list); /* * Add the channel to the DMAC list. Do not add channel 0 though * because we need it internally in the SDMA driver. This also means @@ -2045,6 +2066,7 @@ static int sdma_probe(struct platform_device *pdev) sdma->dma_device.device_prep_dma_cyclic = sdma_prep_dma_cyclic; sdma->dma_device.device_config = sdma_config; sdma->dma_device.device_terminate_all = sdma_disable_channel_with_delay; + sdma->dma_device.device_synchronize = sdma_channel_synchronize; sdma->dma_device.src_addr_widths = SDMA_DMA_BUSWIDTHS; sdma->dma_device.dst_addr_widths = SDMA_DMA_BUSWIDTHS; sdma->dma_device.directions = SDMA_DMA_DIRECTIONS;