From patchwork Tue Dec 16 12:31:26 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wolfram Sang X-Patchwork-Id: 5500451 Return-Path: X-Original-To: patchwork-dmaengine@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id EF77A9F444 for ; Tue, 16 Dec 2014 12:31:50 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 0E7CA20A25 for ; Tue, 16 Dec 2014 12:31:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0E0C020A24 for ; Tue, 16 Dec 2014 12:31:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751113AbaLPMbp (ORCPT ); Tue, 16 Dec 2014 07:31:45 -0500 Received: from sauhun.de ([89.238.76.85]:58727 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750910AbaLPMbn (ORCPT ); Tue, 16 Dec 2014 07:31:43 -0500 Received: from p4fe251e2.dip0.t-ipconnect.de ([79.226.81.226]:56012 helo=localhost) by pokefinder.org with esmtpsa (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.80) (envelope-from ) id 1Y0rHx-0002sY-4D; Tue, 16 Dec 2014 13:31:41 +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 , dmaengine@vger.kernel.org, Vinod Koul Subject: [PATCH 2/2] i2c: sh_mobile: rework deferred probing Date: Tue, 16 Dec 2014 13:31:26 +0100 Message-Id: <1418733086-26324-3-git-send-email-wsa@the-dreams.de> X-Mailer: git-send-email 2.1.3 In-Reply-To: <1418733086-26324-1-git-send-email-wsa@the-dreams.de> References: <1418733086-26324-1-git-send-email-wsa@the-dreams.de> Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@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=unavailable 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 for requesting DMA channels in probe, because our driver would get endlessly deferred if DMA support is compiled in AND 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 PIO transfers under the above scenario. But well, having DMA enabled and the proper DMA driver missing looks like a broken or test config anyhow. 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 2eccbb55dab2..1b7903f5f4b3 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; }