Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752700AbbBQUjZ (ORCPT ); Tue, 17 Feb 2015 15:39:25 -0500 Received: from smtp02.smtpout.orange.fr ([80.12.242.124]:42571 "EHLO smtp.smtpout.orange.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752092AbbBQUjX (ORCPT ); Tue, 17 Feb 2015 15:39:23 -0500 X-ME-Helo: beldin.home X-ME-Date: Tue, 17 Feb 2015 21:39:20 +0100 X-ME-IP: 90.16.210.142 From: Robert Jarzmik To: Daniel Mack , Haojian Zhuang , Robert Jarzmik , Vinod Koul , Arnd Bergmann , Daniel Mack , Vasily Khoruzhick Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org Subject: [PATCH v2 1/2] dma: mmp_dma: add support for legacy transition Date: Tue, 17 Feb 2015 21:39:06 +0100 Message-Id: <1424205547-15429-1-git-send-email-robert.jarzmik@free.fr> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1423954053-21760-1-git-send-email-robert.jarzmik@free.fr> References: <1423954053-21760-1-git-send-email-robert.jarzmik@free.fr> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3547 Lines: 108 In order to achieve smooth transition of pxa drivers from old legacy dma handling to new dmaengine, introduce a function to "hide" dma physical channels from dmaengine. This is temporary situation where pxa dma will be handled in 2 places : - arch/arm/plat-pxa/dma.c - drivers/dma/mmp_pdma.c The resources, ie. dma channels, will be controlled by mmp_dma. The legacy code will request or release a channel with mmp_pdma_toggle_reserved_channel(). This is not very pretty, but it ensures both legacy and dmaengine consumers can live in the same kernel until the conversion is done. Signed-off-by: Robert Jarzmik --- Since v1: fix irq handler to not touch legacy reserved dma interrupts --- drivers/dma/mmp_pdma.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/drivers/dma/mmp_pdma.c b/drivers/dma/mmp_pdma.c index 8926f27..1b82bd6 100644 --- a/drivers/dma/mmp_pdma.c +++ b/drivers/dma/mmp_pdma.c @@ -198,6 +198,15 @@ static int clear_chan_irq(struct mmp_pdma_phy *phy) return 0; } +/* + * In the transition phase where legacy pxa handling is done at the same time as + * mmp_dma, the DMA physical channel split between the 2 DMA providers is done + * through legacy_reserved. Legacy code reserves DMA channels by settings + * corresponding bits in legacy_reserved. + */ +static u32 legacy_reserved; +static u32 legacy_unavailable; + static irqreturn_t mmp_pdma_chan_handler(int irq, void *dev_id) { struct mmp_pdma_phy *phy = dev_id; @@ -221,6 +230,8 @@ static irqreturn_t mmp_pdma_int_handler(int irq, void *dev_id) i = __ffs(dint); dint &= (dint - 1); phy = &pdev->phy[i]; + if ((i < 32) && (legacy_reserved & (1 << i))) + continue; ret = mmp_pdma_chan_handler(irq, phy); if (ret == IRQ_HANDLED) irq_num++; @@ -253,10 +264,14 @@ static struct mmp_pdma_phy *lookup_phy(struct mmp_pdma_chan *pchan) for (i = 0; i < pdev->dma_channels; i++) { if (prio != (i & 0xf) >> 2) continue; + if ((i < 32) && (legacy_reserved & (1 << i))) + continue; phy = &pdev->phy[i]; if (!phy->vchan) { phy->vchan = pchan; found = phy; + if (i < 32) + legacy_unavailable |= (1 << i); goto out_unlock; } } @@ -272,6 +287,7 @@ static void mmp_pdma_free_phy(struct mmp_pdma_chan *pchan) struct mmp_pdma_device *pdev = to_mmp_pdma_dev(pchan->chan.device); unsigned long flags; u32 reg; + int i; if (!pchan->phy) return; @@ -281,6 +297,9 @@ static void mmp_pdma_free_phy(struct mmp_pdma_chan *pchan) writel(0, pchan->phy->base + reg); spin_lock_irqsave(&pdev->phy_lock, flags); + for (i = 0; i < 32; i++) + if (pchan->phy == &pdev->phy[i]) + legacy_unavailable &= ~(1 << i); pchan->phy->vchan = NULL; pchan->phy = NULL; spin_unlock_irqrestore(&pdev->phy_lock, flags); @@ -1121,6 +1140,15 @@ bool mmp_pdma_filter_fn(struct dma_chan *chan, void *param) } EXPORT_SYMBOL_GPL(mmp_pdma_filter_fn); +int mmp_pdma_toggle_reserved_channel(int legacy_channel) +{ + if (legacy_unavailable & (1 << legacy_channel)) + return -EBUSY; + legacy_reserved ^= 1 << legacy_channel; + return 0; +} +EXPORT_SYMBOL_GPL(mmp_pdma_toggle_reserved_channel); + module_platform_driver(mmp_pdma_driver); MODULE_DESCRIPTION("MARVELL MMP Peripheral DMA Driver"); -- 2.1.0 -- 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/