From patchwork Wed Sep 20 18:59:54 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wolfram Sang X-Patchwork-Id: 9962067 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 217E06056E for ; Wed, 20 Sep 2017 19:01:34 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 11A4929202 for ; Wed, 20 Sep 2017 19:01:34 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 05BDF291E6; Wed, 20 Sep 2017 19:01:34 +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=-6.9 required=2.0 tests=BAYES_00,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 A725A29211 for ; Wed, 20 Sep 2017 19:01:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751853AbdITTBF (ORCPT ); Wed, 20 Sep 2017 15:01:05 -0400 Received: from sauhun.de ([88.99.104.3]:38844 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751506AbdITTAF (ORCPT ); Wed, 20 Sep 2017 15:00:05 -0400 Received: from localhost (p54B332E6.dip0.t-ipconnect.de [84.179.50.230]) by pokefinder.org (Postfix) with ESMTPSA id 876B22C43A5; Wed, 20 Sep 2017 21:00:03 +0200 (CEST) From: Wolfram Sang To: linux-i2c@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-iio@vger.kernel.org, linux-input@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, Wolfram Sang Subject: [RFC PATCH v5 4/6] i2c: sh_mobile: use helper to decide if DMA is useful Date: Wed, 20 Sep 2017 20:59:54 +0200 Message-Id: <20170920185956.13874-5-wsa+renesas@sang-engineering.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170920185956.13874-1-wsa+renesas@sang-engineering.com> References: <20170920185956.13874-1-wsa+renesas@sang-engineering.com> Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This ensures that we fall back to PIO if the message length is too small for DMA being useful. Otherwise, we use DMA. A bounce buffer might be applied by the helper if the original message buffer is not DMA safe. Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-sh_mobile.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c index 6f2aaeb7c4fa15..b76399d8a3abd3 100644 --- a/drivers/i2c/busses/i2c-sh_mobile.c +++ b/drivers/i2c/busses/i2c-sh_mobile.c @@ -145,6 +145,7 @@ struct sh_mobile_i2c_data { struct dma_chan *dma_rx; struct scatterlist sg; enum dma_data_direction dma_direction; + u8 *dma_buf; }; struct sh_mobile_dt_config { @@ -548,6 +549,8 @@ static void sh_mobile_i2c_dma_callback(void *data) pd->pos = pd->msg->len; pd->stop_after_dma = true; + i2c_release_dma_safe_msg_buf(pd->msg, pd->dma_buf); + iic_set_clr(pd, ICIC, 0, ICIC_TDMAE | ICIC_RDMAE); } @@ -608,7 +611,7 @@ static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd) if (IS_ERR(chan)) return; - dma_addr = dma_map_single(chan->device->dev, pd->msg->buf, pd->msg->len, dir); + dma_addr = dma_map_single(chan->device->dev, pd->dma_buf, pd->msg->len, dir); if (dma_mapping_error(chan->device->dev, dma_addr)) { dev_dbg(pd->dev, "dma map failed, using PIO\n"); return; @@ -665,7 +668,8 @@ static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg, pd->pos = -1; pd->sr = 0; - if (pd->msg->len > 8) + pd->dma_buf = i2c_get_dma_safe_msg_buf(pd->msg, 8); + if (pd->dma_buf) sh_mobile_i2c_xfer_dma(pd); /* Enable all interrupts to begin with */