From patchwork Thu Aug 28 06:56:17 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Simon Horman X-Patchwork-Id: 4801181 Return-Path: X-Original-To: patchwork-ltsi-dev@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 345ED9F375 for ; Thu, 28 Aug 2014 08:55:54 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5B49E20109 for ; Thu, 28 Aug 2014 08:55:53 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 583C7200F4 for ; Thu, 28 Aug 2014 08:55:52 +0000 (UTC) Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 647A51791; Thu, 28 Aug 2014 07:38:27 +0000 (UTC) X-Original-To: ltsi-dev@lists.linuxfoundation.org Delivered-To: ltsi-dev@mail.linuxfoundation.org Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 4CBED1723 for ; Thu, 28 Aug 2014 07:37:03 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from kirsty.vergenet.net (kirsty.vergenet.net [202.4.237.240]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id 8F3591F88A for ; Thu, 28 Aug 2014 07:37:02 +0000 (UTC) Received: from ayumi.isobedori.kobe.vergenet.net (p4222-ipbfp1605kobeminato.hyogo.ocn.ne.jp [114.154.95.222]) by kirsty.vergenet.net (Postfix) with ESMTP id B162A267240; Thu, 28 Aug 2014 17:08:02 +1000 (EST) Received: by ayumi.isobedori.kobe.vergenet.net (Postfix, from userid 7100) id 2EC8DEDE8E0; Thu, 28 Aug 2014 16:08:00 +0900 (JST) From: Simon Horman To: ltsi-dev@lists.linuxfoundation.org Date: Thu, 28 Aug 2014 15:56:17 +0900 Message-Id: <1409209620-24487-252-git-send-email-horms+renesas@verge.net.au> X-Mailer: git-send-email 2.0.1 In-Reply-To: <1409209620-24487-1-git-send-email-horms+renesas@verge.net.au> References: <1409209620-24487-1-git-send-email-horms+renesas@verge.net.au> X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, 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 Cc: Magnus Damm Subject: [LTSI-dev] [PATCH LTSI-3.14 251/894] spi: Provide core support for full duplex devices X-BeenThere: ltsi-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: "A list to discuss patches, development, and other things related to the LTSI project" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: ltsi-dev-bounces@lists.linuxfoundation.org Errors-To: ltsi-dev-bounces@lists.linuxfoundation.org X-Virus-Scanned: ClamAV using ClamSMTP From: Mark Brown It is fairly common for SPI devices to require that one or both transfer directions is always active. Currently drivers open code this in various ways with varying degrees of efficiency. Start factoring this out by providing flags SPI_MASTER_MUST_TX and SPI_MASTER_MUST_RX. These will cause the core to provide buffers for the requested direction if none are specified in the underlying transfer. Currently this is fairly inefficient since we actually allocate a data buffer which may get large, support for mapping transfers using a scatterlist will allow us to avoid this for DMA based transfers. Signed-off-by: Mark Brown (cherry picked from commit 3a2eba9bd0a6447dfbc01635e4cd0689f5f2bdad) Signed-off-by: Simon Horman --- drivers/spi/spi.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ include/linux/spi/spi.h | 6 ++++++ 2 files changed, 53 insertions(+) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 048eb72..dbab668 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -587,6 +587,49 @@ static int spi_map_msg(struct spi_master *master, struct spi_message *msg) struct device *dev = master->dev.parent; struct device *tx_dev, *rx_dev; struct spi_transfer *xfer; + void *tmp; + size_t max_tx, max_rx; + + if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) { + max_tx = 0; + max_rx = 0; + + list_for_each_entry(xfer, &msg->transfers, transfer_list) { + if ((master->flags & SPI_MASTER_MUST_TX) && + !xfer->tx_buf) + max_tx = max(xfer->len, max_tx); + if ((master->flags & SPI_MASTER_MUST_RX) && + !xfer->rx_buf) + max_rx = max(xfer->len, max_rx); + } + + if (max_tx) { + tmp = krealloc(master->dummy_tx, max_tx, + GFP_KERNEL | GFP_DMA); + if (!tmp) + return -ENOMEM; + master->dummy_tx = tmp; + memset(tmp, 0, max_tx); + } + + if (max_rx) { + tmp = krealloc(master->dummy_rx, max_rx, + GFP_KERNEL | GFP_DMA); + if (!tmp) + return -ENOMEM; + master->dummy_rx = tmp; + } + + if (max_tx || max_rx) { + list_for_each_entry(xfer, &msg->transfers, + transfer_list) { + if (!xfer->tx_buf) + xfer->tx_buf = master->dummy_tx; + if (!xfer->rx_buf) + xfer->rx_buf = master->dummy_rx; + } + } + } if (msg->is_dma_mapped || !master->can_dma) return 0; @@ -759,6 +802,10 @@ static void spi_pump_messages(struct kthread_work *work) } master->busy = false; spin_unlock_irqrestore(&master->queue_lock, flags); + kfree(master->dummy_rx); + master->dummy_rx = NULL; + kfree(master->dummy_tx); + master->dummy_tx = NULL; if (master->unprepare_transfer_hardware && master->unprepare_transfer_hardware(master)) dev_err(&master->dev, diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index dd8b91d..c4c6809 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -350,6 +350,8 @@ struct spi_master { #define SPI_MASTER_HALF_DUPLEX BIT(0) /* can't do full duplex */ #define SPI_MASTER_NO_RX BIT(1) /* can't do buffer read */ #define SPI_MASTER_NO_TX BIT(2) /* can't do buffer write */ +#define SPI_MASTER_MUST_RX BIT(3) /* requires rx */ +#define SPI_MASTER_MUST_TX BIT(4) /* requires tx */ /* lock and mutex for SPI bus locking */ spinlock_t bus_lock_spinlock; @@ -446,6 +448,10 @@ struct spi_master { /* DMA channels for use with core dmaengine helpers */ struct dma_chan *dma_tx; struct dma_chan *dma_rx; + + /* dummy data for full duplex devices */ + void *dummy_rx; + void *dummy_tx; }; static inline void *spi_master_get_devdata(struct spi_master *master)