From patchwork Wed Dec 10 13:21:49 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wolfram Sang X-Patchwork-Id: 5469181 X-Patchwork-Delegate: geert@linux-m68k.org Return-Path: X-Original-To: patchwork-linux-sh@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id A8694BEEA8 for ; Wed, 10 Dec 2014 13:22:38 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 94FBA2011D for ; Wed, 10 Dec 2014 13:22:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4D965200FF for ; Wed, 10 Dec 2014 13:22:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756332AbaLJNWU (ORCPT ); Wed, 10 Dec 2014 08:22:20 -0500 Received: from sauhun.de ([89.238.76.85]:59619 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756270AbaLJNV6 (ORCPT ); Wed, 10 Dec 2014 08:21:58 -0500 Received: from p4fe243fb.dip0.t-ipconnect.de ([79.226.67.251]:36759 helo=localhost) by pokefinder.org with esmtpsa (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.80) (envelope-from ) id 1XyhDI-0000CC-Iv; Wed, 10 Dec 2014 14:21:56 +0100 From: Wolfram Sang To: linux-i2c@vger.kernel.org Cc: linux-sh@vger.kernel.org, Wolfram Sang , Magnus Damm , Simon Horman , Laurent Pinchart , Geert Uytterhoeven Subject: [RFC 2/2] i2c: sh_mobile: rework deferred probing Date: Wed, 10 Dec 2014 14:21:49 +0100 Message-Id: <1418217709-26392-3-git-send-email-wsa@the-dreams.de> X-Mailer: git-send-email 2.1.3 In-Reply-To: <1418217709-26392-1-git-send-email-wsa@the-dreams.de> References: <1418217709-26392-1-git-send-email-wsa@the-dreams.de> Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Wolfram Sang DMA is opt-in for this driver. So, we can't use deferred probing in probe, because our driver would get endlessly deferred if DMA support is compiled in but only the DMA driver is missing. Because we can't know when the DMA driver might show up, we always try again when a DMA transfer would be possible. The downside is that there is more overhead for setting up every DMA transfer. Reported-by: Geert Uytterhoeven Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-sh_mobile.c | 98 +++++++++++++++++++------------------- 1 file changed, 48 insertions(+), 50 deletions(-) diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c index 636f2297143a..ea7b99212fa6 100644 --- a/drivers/i2c/busses/i2c-sh_mobile.c +++ b/drivers/i2c/busses/i2c-sh_mobile.c @@ -144,6 +144,7 @@ struct sh_mobile_i2c_data { int sr; bool send_stop; + struct resource *res; struct dma_chan *dma_tx; struct dma_chan *dma_rx; struct scatterlist sg; @@ -543,6 +544,41 @@ static void sh_mobile_i2c_dma_callback(void *data) iic_set_clr(pd, ICIC, 0, ICIC_TDMAE | ICIC_RDMAE); } +static struct dma_chan *sh_mobile_i2c_request_dma_chan(struct device *dev, + enum dma_transfer_direction dir, dma_addr_t port_addr) +{ + struct dma_chan *chan; + struct dma_slave_config cfg; + char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx"; + int ret; + + chan = dma_request_slave_channel_reason(dev, chan_name); + if (IS_ERR(chan)) { + dev_dbg(dev, "request_channel failed for %s (%d)\n", chan_name, ret); + return chan; + } + + memset(&cfg, 0, sizeof(cfg)); + cfg.direction = dir; + if (dir == DMA_MEM_TO_DEV) { + cfg.dst_addr = port_addr; + cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; + } else { + cfg.src_addr = port_addr; + cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; + } + + ret = dmaengine_slave_config(chan, &cfg); + if (ret) { + dev_dbg(dev, "slave_config failed for %s (%d)\n", chan_name, ret); + dma_release_channel(chan); + return ERR_PTR(ret); + } + + dev_dbg(dev, "got DMA channel for %s\n", chan_name); + return chan; +} + static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd) { bool read = pd->msg->flags & I2C_M_RD; @@ -552,6 +588,15 @@ static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd) dma_addr_t dma_addr; dma_cookie_t cookie; + if (PTR_ERR(chan) == -EPROBE_DEFER) { + if (read) + chan = pd->dma_rx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_DEV_TO_MEM, + pd->res->start + ICDR); + else + chan = pd->dma_tx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_MEM_TO_DEV, + pd->res->start + ICDR); + } + if (IS_ERR(chan)) return; @@ -749,41 +794,6 @@ static const struct of_device_id sh_mobile_i2c_dt_ids[] = { }; MODULE_DEVICE_TABLE(of, sh_mobile_i2c_dt_ids); -static struct dma_chan *sh_mobile_i2c_request_dma_chan(struct device *dev, - enum dma_transfer_direction dir, dma_addr_t port_addr) -{ - struct dma_chan *chan; - struct dma_slave_config cfg; - char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx"; - int ret; - - chan = dma_request_slave_channel_reason(dev, chan_name); - if (IS_ERR(chan)) { - dev_dbg(dev, "request_channel failed for %s (%d)\n", chan_name, ret); - return chan; - } - - memset(&cfg, 0, sizeof(cfg)); - cfg.direction = dir; - if (dir == DMA_MEM_TO_DEV) { - cfg.dst_addr = port_addr; - cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; - } else { - cfg.src_addr = port_addr; - cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; - } - - ret = dmaengine_slave_config(chan, &cfg); - if (ret) { - dev_dbg(dev, "slave_config failed for %s (%d)\n", chan_name, ret); - dma_release_channel(chan); - return ERR_PTR(ret); - } - - dev_dbg(dev, "got DMA channel for %s\n", chan_name); - return chan; -} - static void sh_mobile_i2c_release_dma(struct sh_mobile_i2c_data *pd) { if (!IS_ERR(pd->dma_tx)) { @@ -846,6 +856,7 @@ static int sh_mobile_i2c_probe(struct platform_device *dev) res = platform_get_resource(dev, IORESOURCE_MEM, 0); + pd->res = res; pd->reg = devm_ioremap_resource(&dev->dev, res); if (IS_ERR(pd->reg)) return PTR_ERR(pd->reg); @@ -886,19 +897,7 @@ static int sh_mobile_i2c_probe(struct platform_device *dev) /* Init DMA */ sg_init_table(&pd->sg, 1); pd->dma_direction = DMA_NONE; - pd->dma_rx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_DEV_TO_MEM, - res->start + ICDR); - ret = PTR_ERR(pd->dma_rx); - if (ret == -EPROBE_DEFER) - return ret; - - pd->dma_tx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_MEM_TO_DEV, - res->start + ICDR); - ret = PTR_ERR(pd->dma_tx); - if (ret == -EPROBE_DEFER) { - sh_mobile_i2c_release_dma(pd); - return ret; - } + pd->dma_rx = pd->dma_tx = ERR_PTR(-EPROBE_DEFER); /* Enable Runtime PM for this device. * @@ -936,8 +935,7 @@ static int sh_mobile_i2c_probe(struct platform_device *dev) return ret; } - dev_info(&dev->dev, "I2C adapter %d, bus speed %lu Hz, DMA=%c\n", - adap->nr, pd->bus_speed, (pd->dma_rx || pd->dma_tx) ? 'y' : 'n'); + dev_info(&dev->dev, "I2C adapter %d, bus speed %lu Hz\n", adap->nr, pd->bus_speed); return 0; }