From patchwork Tue Dec 24 12:06:27 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Popov X-Patchwork-Id: 304956 X-Patchwork-Delegate: agust@denx.de Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from ozlabs.org (localhost [IPv6:::1]) by ozlabs.org (Postfix) with ESMTP id 752642C0756 for ; Tue, 24 Dec 2013 23:04:44 +1100 (EST) Received: from mail-lb0-x22f.google.com (mail-lb0-x22f.google.com [IPv6:2a00:1450:4010:c04::22f]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 613542C00B9 for ; Tue, 24 Dec 2013 23:02:54 +1100 (EST) Received: by mail-lb0-f175.google.com with SMTP id w6so2794266lbh.20 for ; Tue, 24 Dec 2013 04:02:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:subject:date:message-id:in-reply-to:references; bh=xlD384L68aPDR88Zo+cdsNSaoc05pBAyBLiOuRDblYw=; b=eHnrfhBHWuYOkKe7vbVcfWG0JUNcHbUeCCO22rgcdg/Pj7l8L55PR7lq78HxGgYc1c C0c26n8vppTbrpBg/O2DRsPc/lSZhN6b+tnWzxdfHePxQ6lf5XxnYRkWkHAlVhqNvWRT pF3k3mCKankqc50mfBg1zRBXx+2Ay+mbhTFKPPVNnhjxyyucpNU7749FS36MPwknGt6I w3xLrtebn+xS7rbPjlXwidXoCTtwXtQfjtgd56DIXYXYtmLm/lCt6c1p8nyq1agYRQn/ gOPhf/3uwJUkWsV/ybOoIn0vKRt3XhNtAar5lSo7Y51oeVY8hRfwp40YyJN5DE2pjG++ Z2Aw== X-Received: by 10.112.157.234 with SMTP id wp10mr773851lbb.50.1387886569565; Tue, 24 Dec 2013 04:02:49 -0800 (PST) Received: from a13xCCC.localdomain (mail.tecon.ru. [89.175.104.62]) by mx.google.com with ESMTPSA id sd11sm17736051lab.2.2013.12.24.04.02.48 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Tue, 24 Dec 2013 04:02:49 -0800 (PST) From: Alexander Popov To: Gerhard Sittig , Dan Williams , Vinod Koul , Lars-Peter Clausen , Arnd Bergmann , Anatolij Gustschin , Alexander Popov , linuxppc-dev@lists.ozlabs.org, dmaengine@vger.kernel.org, devicetree@vger.kernel.org Subject: [PATCH RFC v6 3/5] dma: of: Add common xlate function for matching by channel id Date: Tue, 24 Dec 2013 16:06:27 +0400 Message-Id: <1387886789-20249-4-git-send-email-a13xp0p0v88@gmail.com> X-Mailer: git-send-email 1.7.11.3 In-Reply-To: <1387886789-20249-1-git-send-email-a13xp0p0v88@gmail.com> References: <1387886789-20249-1-git-send-email-a13xp0p0v88@gmail.com> X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.16 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" This patch adds a new common OF dma xlate callback function which will match a channel by it's id. The binding expects one integer argument which it will use to lookup the channel by the id. Unlike of_dma_simple_xlate this function is able to handle a system with multiple DMA controllers. When registering the of dma provider with of_dma_controller_register a pointer to the dma_device struct which is associated with the dt node needs to passed as the data parameter. New function will use this pointer to match only channels which belong to the specified DMA controller. Signed-off-by: Alexander Popov --- drivers/dma/of-dma.c | 35 +++++++++++++++++++++++++++++++++++ include/linux/of_dma.h | 4 ++++ 2 files changed, 39 insertions(+) diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c index 0b88dd3..03a375e 100644 --- a/drivers/dma/of-dma.c +++ b/drivers/dma/of-dma.c @@ -215,3 +215,38 @@ struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec, &dma_spec->args[0]); } EXPORT_SYMBOL_GPL(of_dma_simple_xlate); + +/** + * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id + * @dma_spec: pointer to DMA specifier as found in the device tree + * @of_dma: pointer to DMA controller data + * + * This function can be used as the of xlate callback for DMA driver which wants + * to match the channel based on the channel id. When using this xlate function + * the #dma-cells propety of the DMA controller dt node needs to be set to 1. + * The data parameter of of_dma_controller_register must be a pointer to the + * dma_device struct the function should match upon. + * + * Returns pointer to appropriate dma channel on success or NULL on error. + */ +struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec, + struct of_dma *ofdma) +{ + struct dma_device *dev = ofdma->of_dma_data; + struct dma_chan *chan, *candidate = NULL; + + if (!dev || dma_spec->args_count != 1) + return NULL; + + list_for_each_entry(chan, &dev->channels, device_node) + if (chan->chan_id == dma_spec->args[0]) { + candidate = chan; + break; + } + + if (!candidate) + return NULL; + + return dma_get_slave_channel(candidate); +} +EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id); diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h index ae36298..56bc026 100644 --- a/include/linux/of_dma.h +++ b/include/linux/of_dma.h @@ -41,6 +41,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct device_node *np, const char *name); extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec, struct of_dma *ofdma); +extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec, + struct of_dma *ofdma); #else static inline int of_dma_controller_register(struct device_node *np, struct dma_chan *(*of_dma_xlate) @@ -66,6 +68,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_s return NULL; } +#define of_dma_xlate_by_chan_id NULL + #endif #endif /* __LINUX_OF_DMA_H */