From mboxrd@z Thu Jan 1 00:00:00 1970 From: mika.westerberg@iki.fi (Mika Westerberg) Date: Mon, 21 Nov 2011 10:01:58 +0200 Subject: [PATCH v2 1/5] dmaengine: add ep93xx DMA support In-Reply-To: <4ECA0147.4020806@metasoft.pl> References: <3ea8d56034f25cbe3fd8a4c31d7d0d1540b6ac7e.1306662317.git.mika.westerberg@iki.fi> <4EC27EED.4030108@metasoft.pl> <20111116065512.GB2703@mwesterb-mobl.ger.corp.intel.com> <4EC374F0.8000400@metasoft.pl> <20111119123837.GA2711@mwesterb-mobl.ger.corp.intel.com> <4ECA0147.4020806@metasoft.pl> Message-ID: <20111121080158.GA2713@mwesterb-mobl.ger.corp.intel.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Nov 21, 2011 at 08:44:07AM +0100, Rafal Prylowski wrote: > > I'm calling dma_terminate_all from interrupt. It seems that tasklet_kill is not > allowed to be called from this context. Ah, right. One more try - this time we set a flag which prevents the tasktlet from referencing an empty list. diff --git a/drivers/dma/ep93xx_dma.c b/drivers/dma/ep93xx_dma.c index 6181811..f7244b3 100644 --- a/drivers/dma/ep93xx_dma.c +++ b/drivers/dma/ep93xx_dma.c @@ -155,6 +155,8 @@ struct ep93xx_dma_chan { unsigned long flags; /* Channel is configured for cyclic transfers */ #define EP93XX_DMA_IS_CYCLIC 0 +/* Channel is enabled */ +#define EP93xx_DMA_IS_RUNNING 1 int buffer; dma_cookie_t last_completed; @@ -673,6 +675,9 @@ static void ep93xx_dma_tasklet(unsigned long data) void *callback_param; LIST_HEAD(list); + if (!test_bit(EP93XX_DMA_IS_RUNNING, &edmac->flags)) + return; + spin_lock_irq(&edmac->lock); desc = ep93xx_dma_get_active(edmac); if (desc->complete) { @@ -758,6 +763,8 @@ static dma_cookie_t ep93xx_dma_tx_submit(struct dma_async_tx_descriptor *tx) edmac->chan.cookie = cookie; desc->txd.cookie = cookie; + set_bit(EP93XX_DMA_IS_RUNNING, &edmac->flags); + /* * If nothing is currently prosessed, we push this descriptor * directly to the hardware. Otherwise we put the descriptor @@ -1106,6 +1113,7 @@ static int ep93xx_dma_terminate_all(struct ep93xx_dma_chan *edmac) spin_lock_irqsave(&edmac->lock, flags); /* First we disable and flush the DMA channel */ edmac->edma->hw_shutdown(edmac); + clear_bit(EP93XX_DMA_IS_RUNNING, &edmac->flags); clear_bit(EP93XX_DMA_IS_CYCLIC, &edmac->flags); list_splice_init(&edmac->active, &list); list_splice_init(&edmac->queue, &list);