Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753716Ab0HPLIO (ORCPT ); Mon, 16 Aug 2010 07:08:14 -0400 Received: from metis.ext.pengutronix.de ([92.198.50.35]:58968 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753599Ab0HPLH6 (ORCPT ); Mon, 16 Aug 2010 07:07:58 -0400 From: Sascha Hauer To: linux-kernel@vger.kernel.org Cc: Linus Walleij , Dan Williams , linux-arm-kernel@lists.infradead.org, Sascha Hauer , Haavard Skinnemoen Subject: [PATCH 1/3] dmaengine: add possibility for cyclic transfers Date: Mon, 16 Aug 2010 13:07:48 +0200 Message-Id: <1281956870-12463-2-git-send-email-s.hauer@pengutronix.de> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1281956870-12463-1-git-send-email-s.hauer@pengutronix.de> References: <1281956870-12463-1-git-send-email-s.hauer@pengutronix.de> X-SA-Exim-Connect-IP: 2001:6f8:1178:2:215:17ff:fe12:23b0 X-SA-Exim-Mail-From: sha@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2349 Lines: 63 Cyclic transfers are useful for audio where a single buffer divided in periods has to be transfered endlessly until stopped. After being prepared the transfer is started using the dma_async_descriptor->tx_submit function. dma_async_descriptor->callback is called after each period. The transfer is stopped using the DMA_TERMINATE_ALL callback. While being used for cyclic transfers the channel cannot be used for other transfer types. Signed-off-by: Sascha Hauer Cc: Haavard Skinnemoen --- drivers/dma/dmaengine.c | 2 ++ include/linux/dmaengine.h | 6 +++++- 2 files changed, 7 insertions(+), 1 deletions(-) diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 9d31d5e..e5e79ce 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -692,6 +692,8 @@ int dma_async_device_register(struct dma_device *device) !device->device_prep_dma_interrupt); BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) && !device->device_prep_slave_sg); + BUG_ON(dma_has_cap(DMA_CYCLIC, device->cap_mask) && + !device->device_prep_dma_cyclic); BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) && !device->device_control); diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index c61d4ca..0df7864 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -67,10 +67,11 @@ enum dma_transaction_type { DMA_PRIVATE, DMA_ASYNC_TX, DMA_SLAVE, + DMA_CYCLIC, }; /* last transaction type for creation of the capabilities mask */ -#define DMA_TX_TYPE_END (DMA_SLAVE + 1) +#define DMA_TX_TYPE_END (DMA_CYCLIC + 1) /** @@ -478,6 +479,9 @@ struct dma_device { struct dma_chan *chan, struct scatterlist *sgl, unsigned int sg_len, enum dma_data_direction direction, unsigned long flags); + struct dma_async_tx_descriptor *(*device_prep_dma_cyclic)( + struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len, + size_t period_len, enum dma_data_direction direction); int (*device_control)(struct dma_chan *chan, enum dma_ctrl_cmd cmd, unsigned long arg); -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/